.~
"­­*
/
A
+­
7
,
­y,
I
f
%

.c,
t
BEFORE
THX'~
'ADMINISTRATOR
OF
THE~
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
­

1
INTERNATIONAL
CENTER
FOR
1
HON.
TECHNOLOGY
ASSESSMENT,
310
D
Street,
N.
E.
Washington,
DC
20002,
et
al.,

Petitioners,

vs
.
3
CAROL
BRO
WlER?
in
her
official
capacity
as,
Administrator
of
the
United
States
Environmental
Protection
Agency
401
M
Street,
S.
W.
Room
W1200
Washington,
DC
20460,
d
..

Defendant.
OCT
2
0
I999
Docket'No.
A"­
O#

PETITION
FOR
RULEMAKING
AND
COLLATERAL
RELIEF
FROM
NEW
MOTOR
VEHICLES
UNDER
Q
202
OF
THE
CLEAN
AIR
ACT
SEEKING
THE
REGULATION
OF
GREENHOUSE
GAS
EMISSIONS
Pursuant
to
the
Right
to
Petition
Government
Clause
contained
in
the
First
Amendment
of
the
United
States
Constitution,
'
the
Administrative
Procedure
Act,*

­Tb3
i
'Congress
shall
make
no
law
.
.
.
abridging
.
.
.
the
right
of
the
people
.
.
.
to
petition
Government
for
a
redress
of
grievances."
U.
S.
Const.,
amend.
I.
The
right
to
petition
for
redress
of
grievances
is
among
the
most
precious
of
the
liberties
safeguarded
by
the
Bill
of
€?
i,
ohts.
United
Mine
Workers
of
America.
Dist.
12
v
.
Illinois
State
Bar
Association,
389
U.
S.
217,
222,
88
S.
Ct.
353,356,
19
L.
Ed.
2d426
(1967).
It
shares
the
"preferred
.
place"
accorded
in
our
system
of
government
to
the
First
Amendment
freedoms,
and
has
a
sanctity
and
a
sanction
not
permitting
dubious
intnisions.
Thomas
v.
Collins,
323
U.
S.
516,530,65
S.
Ct.
315,
322,
S9
L.
Ed.
430
(1945).

..
.
.
.
/.
P
,

the
Clean
Air
and
the
Environmental
Protection
Agency("
EPA")
implementing
,
regulations,
petitioners
file
this
Petition
for
Rulemaking
and
Collateral.
Relief
with
­

a
the
Administrator
and
respectfully
requests
her
to
undertake
the
following
mandatory
duties:

Regulate
the
emissions
of
carbon
dioxide
(CO,)
from
new
motor
vehicles
and
new
motor
vehicle
engines
under
!j
202(
a)(
1)
of
the
Clean
Air
Act;

Regulate
the
emissions
of
methane
(CH,)
from
new
motor
vehicles
and
new
motor
vehicle
engines
under
§
202(
a)(
1)
of
the
Clean
Air
Act;

Regulate
the
emissions4f
nitrous
oxide
(N,
O)
from
new
motor
vehicles
and
new
motor
vehicle
engines
under
5
202(
a)(
1)
of
the
Clean
Air
Act;

Regulate
the
emissions
of
hydrofluorocarbons
(HFCs)
from
new
motor
vehicles
and
new
motor
vehicle
engines
under
5
202(
a)(
1)
of
the
Clean
Air
Act;
­

PETITIONERS
Petitioner
International
Center
for
Technology
Assessment
(CTA)
is
located
at
310
D
Street,
N.
E.,
Washington,
DC
20002.
Formed
in
1994,
CTA
seeks
to
assist
the
public
and
policy
makers
in
better
understanding
how
technology
affects
society.­
CTA
is
a
non­
profit
organization
devoted
to
analyzing
the
economic,
environmental,
ethical,
political
and
social
impacts
that
can
result
from
the
application
of
technology
or
technological
systems.

Petitioner
Alliance
f
o
r
Sustainable
Communities
is
located
at
2041
Shore
"Any
attempt
to
restrict
those
First
Amendment
liberties
i
u
s
t
be
justified
by
clear
public
interest,
threatened
not
doubtful
or
remotely,
but
by
clear
and
present
danger."&
The
Supreme
Court
has
recognized
that
the
right
to
petition
is
logically
implicit
in,
and
fundamental
to,
the
very
idea
of
a
republican
form
of
government.
United
States
v.
Cmikshank,
92
U.
S.
(2
Otto)
542,
552,
23
L.
Ed.
585
(1375).

2
5
U.
S.
C.
9
553(
e)
(1994).

42
U.
S.
C.
7401,
etseq.
(1994).
3
Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
to
EPA
­
October
10,
1999
2
/

".
.­
/

Drive,
Edgewater,
MD
2
1037.
The
Alliance
was
formed
five
years
ago
in
order
to
bring
together
representatives
of
government
at
all
levels,
citizens
and
innovslors
O
b
to
develop
projects
which
express
the
primary
relationship'between
people
and
the
earth.
­

t
Petitioner
Applied
Power
TechnoZogies,
Inc.
(APT)
is
located
at
357
Imperial
Blvd.,
Cape
Canaveral,
FL
32920­
42
19.
APT
is
a
research
&
development
concern
bringing
new
energy
conversion
systems
to
the
air­
conditioning
industry
on
behalf
of
the
natural
gas
industry.
APT
will
advent
the
deregulation
and
decentralization
of
power
production
by
producing
nearly
pollution­
free
air­
conditioning,
refrigeration
and
related
appliances
which
will
convert
clean
natural
gas
into
electric
offsetting
heat
energy
on­
site
of
actual
end
usage.

Petitioner
Bio
Fuels
America
s
located
at
28
Lorin
Dee
Drive,
Westerlo,
Ny
12
193.
Bio
Fuels
America
is
a
not
for
profit,
self
funded,
advocacy
group
that
promotes
renewable
energies
such
as
wind,
sun
and
biomass.
.j
Petitioner
The
CaliJomia
Solar
Energy
Industries
Association
(CAL
SEIA)
is
located
at
23120
Alicia
Parkway,
Ste.
107,
Mission
Viejo,
CA
92692.
CAL
SEIA
is
a
solar
industry
trade
association
with
70
member
companies
who
do
busimess
in
California.
CAL
SEIA's
members
include
manufacturers
of
both
solar
thermal
and
photovoltaic
technologies,
as.
'kell
as
distributors,
contractors,
architects,
engineers
and
utilities.
*

Petitioner
Clements
Environmental
Co7poration
is
located
at
3607
Seneca
Avenue,
Los
Angeles,
CA
90039.
Clements
Environmental
Corp.
is
a
small
environmental
engineering
firm
specializing
in
the
conversion
of
Municpal
Solid
Waste
and
other
waste
organics
to
biofuels
and
biochemicals.

.Petitioner
Environmental
Advocates
is
located
a
t
353
Hamilton
Street,
Albany,
NY
122
10.
Environmental
Advocates
serves
the
people
of
New
York
as
an
effective
and
aggressive
watchdog
and
advocate
on
virtually
every
important
state
environmental
issue.
Through
advocacy,
coalition
building,
citizen
education
and
policy
development,
we
work
to
safeguard
public
health
and
preserve
our
unique
natural
heritage.
With
thousands
of
individual
supporters
and
over
130
organizational
members,
Environmental
Advocates
is
truly
the
voice
of
New
York's
environmental
community;

Petitioner
Environmental
and
Energy
Study
Institute
(&
BSl)
is
located
at
i22
C
St.
XW,
Suice
'700,
lb'ashington,
D.
C.
20001.
EESI
is
a
Eon­
profit
organization
founded
in
1982
by
a
bipartisan
group
of
Members
of
Congress.
EESI
promotes
public
policy
that
sustains
people,
the
environment
and
our
natural
resources.

Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
to
EPA
­
October
20,
1999
3
....
.........
..
....
......
.....
..
....
...
.­
..
....
EESI's
wide­
ranging
audience
includes
Congress
and
other
national
policymakers,
as
well
as
state
and
local
officials,
industry
leaders,
the
public
interest
a
'
community,­
the
media,
and
the
general
public.
EESI
draws
together
timely
information,
innovative
public
policy
proposals,
policymakers,
and
stakeholders
to
seek
solutions
to
environmental
and
energy
problems.

Petitioner
Friends
ofthe
Earth
is
located
at
1025
Vermont
Ave.,
NW,
Suite
300,
Washington,
DC
20005
Friends
of
the
Earth
is
a
national
environmental
organization
dedicated
to
preserving
the
health
and
diversity
of
the
planet
for
future
generations.
A
s
the
largest
international
environmental
network
in
the
world
with
affiliates
in
63
countries,
Friends
of
the
Earth
empowers
citizens
to
have
an
influential
voice
in
decisions
affecting
their
environment.

Petitioner
FUZZ
Circle
Energy
Ep­
oject,
Inc.
is
located
a
t
6
Brooklawn
Road,
Wilbraham,
MA
01095­
2002.
Full
Circle
Energy
Project,
Inc.
is
a
non­
profit
organization
founded
to
enable
environmentally
sensible
and
sustainable
energy
resources
to
supply
at
least
50%
of
the
total
energy
used
in
the
United
States.
Its
primary
focus
is
on
reducing
the
amount
of
fossil
fuels
used
by
the
transportation
sector.
­

Petitioner
The
Green
Party
oJRhode
Island
is
located
in
Providence,
RI.
The
Green
Party
of
RI
is
a
part
of
the
international
Green
Party
movement.
In
Rhode
Island
it
has
run
candidates
'for
a
variety
of
offices,
always
focusing
on
environmental
issues
as
well
as
justice,
non
violence,
and
democracy
issues.

Petitioner
Greenpeace
USA
is
located
at
1436
U
Street,
NW,
Washington,
DC
20009.
Greenpeace
is
one
of
the
world's
major
environmental
organizations
with
offices
in
33
countries,
including
the
United
States
of
America,
and
over
3
million
donating
supporters
worldwide.
Greenpeace
is
a
non­
profit
organization
devoted
to
the
protection
of
the
environment
with
an
emphasis
on
global
environmental
problems
such
as
climate
change
and
protection
of
the
stratospheric
ozone
layer,
prevention
of
nuclear,
chemical
and
biological
pollution,
and
defense
of
biodiversity.

Petitioner
Network
for
Environmental
and
Economic
Responsibility
of
the
United
Church
of
Christ,
Washington
Office,
1820
Sanford
Road,
Wheaton,
MD
20902­
4008.
The
Network
for
Environmental
and
Economic
Responsibility
(NEER)
is
a
grmsroots,
volunteer
movement
committed
to
mobilizing
UCC
persons,
networks
and
resources
for
a
holistic
rninistrJr
of
learning,
reflection,
and
action
cognizant
of
the
earth
and
its
creatures.
Network
members
believe
that
all
living
things
on
our
planet
are
interdependent
in
a
vast
web
of
life.

Int'l.
Ctr.
for
Tech.
Xssm't.
Legal
Petition
to
EPA
­October
20,
1999
4
..
.
.
..
..
.
..
.
..
..
,/

Petitioner
New
Jersey
Environmental
Watchis
located
c/
o
St.
John's
Church,

e
*
61
Broad
Street,
Elizabeth,
N
J
07201.
New
Jersey
Environmental
Watch
is
a
church
based
organization
in
New
Jersey
that
seeks
better
air
in
their
area
and
elsewhere.
Recently,
it
recorded
40
percent
of
our
Sunday
School
children
had
been
hospitalized
for
asthma.
I
t
is
also
in
cancer
alley
and
have
greatly
elevated
cancer
rates.
The
14­
lane
New
Jersey
Turnpike
passes
through
Elizabeth,
NJ
the
bottom
40
percent
of
the
Newark
Airport
is
located
there
as
well,
and
Elizabeth
is
immediately
downwind
of
the
huge
Bayway
Tosco
refine7
in
Linden.
­

Petitioner
New
Mexico
Solar
Energy
Association
(NMSEA)
is
located
at
P.
O.
Box
8507
Santa
Fe,
NM
87505.
NMSEA
is
an
all
volunteer
organization
working
to
further
solar
and
related
arts,
sciences,
and
technologies
with
concern
for
the
ecologic,
social
and
economic
fabr&
of
the
region.
It
serves
to
inform
public,
institutional
and
government
bodies
and
seeks
to
raise
the
level
of
public
awareness
of
these
purposes.

Petitioner
Oregon
Environmental
Council(
OEC)
is
located
at
520
SW
6&
Avenue,
Suite
940,
Portland,
OR
97204­
1535.
OEC,
founded
in
1968,
is
Oregon's
oldest
statewide
environmental
group.
OEC
works
to
restore
and
protect
Oregon's
water
and
air
by
creating
and
promoting
environmental
policies.

Petitioner
Public
Citizen
.is
located
at
2
15
Pennsylvania
Ave.,
SE,
Washington,
DC
20003.
Public
Citizen,
founded
by
Ralph
Nader
in
1971,
is
a
non­
profit
research,
lobbying,
and
litigation
organization
based
in'washington,
DC.
Public
Citizen
advocates
for
consumer
protection
and
for
government
and
corporate
accountability,
and
is
supported
by
over
150,000
members
throughout
the
United
States.
.*

.­

Petitioner
Solar
Energy
Industries
Association
(SEIA)
is
located
at
1
1
1
1
North
19th
Street,
Suite
260,
Arlington,
VA
22209.
The
Solar
Energy
industries
Association
(SEIA),
founded
in
­1974,
is
the
U.
S.
industry
organization
composed
of
over
150
solar­
electric
and
solar
thermal
manufacturers,
component
suppliers,
national
distibutors
and
project
developers,
and
an
additional
400
companies
in
the
SEIA­­
affiliated
state
and
regional
chapters
covering
35
states.

Petitioner
The
SUNDAY
Campaign
is
located
at
3
15
Circle
Avenue,
Suite
#2,
Takoma
Park,
MD
20912­
4836.
The
SUN
DAY
Campaign
is
a
non­
profit
network
of
850+
businesses
and
organizations
founded
in
1991
to
promote
increased
use
of
renewable
energy
and
energy
efficient
technologies.
Areas
of
work
include
research
on
sustainable
energy
technologies,
electric
utility
restructuring,
climate
change,
and
the
federal
energy
budget.
Projects
include
publication
of
a
weekly
Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
to
EPA
­
October
20,
1999
5
...

.
.
.
.
.
.
.
.
­
..
..
..
..
,
P
/

newsletter,
an
annual
series
of
directories
of
sustainable
energy
organizations,
and
other
studies.
*`
­
"

STATEMENT
OF
LAW
Clean
Air
Act,
Section
302(
g),
42
U.
S.
C.
3
7602(
g):

The
term
"air
pollutant"
means
any
air
pollution
agent
or
combination
of
such
agents,
including
any
physical,
chemical,
biological,
radioactive
(including
source
material,
`special
nuclear
material,
and
byproduct
material)
substance
or
matter
which
is
emitted
into
or
otherwise
e
n
t
e
s
ambient
air.
Such
term
includes
any
precursors
to
the
formation
of
any
air
pollutant,
to
the
extent
the
Administrator
has
identified
such
precursor
or
precursors
for
the
particular
purpose
for
which
the
term
"air
pollutant"
is
used.

Clean
Air
Act,
Section
202(
a)(
l),
42
U.
S.
C.
$j
7521(
a)(
1):
­

\

The
Administrator
shall
by
regulation
prescribe
(and
from
time
to
time
revise)
in
accordance
with
the
provisions
of
this
section,
standards
applicable
to
the
emission
of
any
air
pollutant
from
any
class
or
classes
of
new
motor
vehicle
or
new
motor
vehicle
engine,
which
in
his
judgment
cause,
or
contribute
to,
air
pollution
which
may
be
reasonably
anticipated
to
endanger
public
health
or
welfare.
Such
standards
shall
be
applicable
to
such
vehicles
and
engines
for
the
useful
life
...
whether
such
vehicle
or
engines
are
designed
as
complete
systems
or
incorporate
to
devices
to
prevent
the
control
of
such
pollution.

U.
S.
Constitution,
amendment
I
Administrative
Procedure
Act,
5
U.
S.
C.
§
551,
et
seq.

Int'l.
Ctr.
for
Tech.
Xssm't.
Legal
Petition
to
EPA
­
Octobcr
20,
1999
6
..
............
..
....
..
...
.......
......
......
...
...
....
­
.............
­
..
:
.".
,
,
,".
,/`
I
/

All
other
applicable
statutes
and
regulations.

4
4
­
BRIEF
STATEMENT
OF
FACT
The
Earth's
temperature
is
increasing.
Scientists
from
the
National
Oceanic
and
Atmospheric
Administration
("
NOM'),
the
U.
S.
Regional
Climate
Centers,
and
the
World
Meteorological
Organization
all
agree
that
1998
was
the
walmest
yeal­

on
rec01­
d.~
The
temperature
increase's
recorded
in
1998
represent
a
steady
trend
over
the
past
twenty
years
of
record
breaking
global
surface
temperature^.^
The
United
Nations
intergovernmental
Panel
on
Climate
Change
("
IPCC"),
an
authoritative
body
of
more
than
&o
thousand
of
the
world's
leading
climate
change
scientists,
stated
that
the
emission
of
anthropogenic
greenhouse
gases,

including
carbon
dioxide
(TO,"),
methane
("
CH,"),
nitrous
oxide
("
N,
O"),
and
hydrofluorocarbons
("
HFCs")
[hereinafter
referred
to
collectively
as
"greenhouse
­

gases"],
are
significantly
accelerating
this
current
warming
trend.
6
Human
activities
are
increasing
the
concentration
of
heat
trapping
greenhouse
gases
in
the
atmosphere
and
the
effect
is
called
global
warming.
Due
to
these
high
fossil
fuel
emission
levels,
the
IPCC
warned
that:

carbon
dioxide
remains
the
most
important
contributor
to
anthropogenic
forcing
of
climate
change:
projections
of
future
global
mean
temperature
change
and
sea
level
rise
confirrn'the
potential
for
human
activities
t
o
alter
Earth's
climate
to
extent
unprecedented
in
human
hist01­
y.~
'
­

4
National
Oceanic
and
At~
nospheric
Adrninistration
(January
12,
1999),
h~
tp:
l/~~~~
w.
ncdc.
noaa.
povlol/
climate/
rese~
rch/
199S/
ann/
ann9S.
html.

5
­
Id.

6
United
Katiox
Enviroi1mcntal
Prograinme
(UXEP)/
lYorld
bleteoroiogical
Organization
(WhiO),

Clirnate
Change
193j:
The
Science
of
Clilnate
Chance.
Technical
Sunirrlary
of
Workin:
Group
I
of
the
Inter,
oovernmentnl
Panel
on
Climate
Chanze
[hereinafter
Climate
Change
1995,
Pet.
Ex.
11.

7
­
Id.
at
3.

Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
t
o
EPX
­
October
20,1999
7
.
­..

..........
..
.........
..
..
...........
....
/
I
/".
1
.".

Approximately
90%
of
U.
S.
greenhouse
gas
emissions
from
anthropogenic
,
sources
occurs
because
of
the
combustion
of
fossil
U.
S.
mobile
sourc&
are
responsible­
for
a
significant
amount
of
greenhouse
gas
emissions.
In
fact,
in
the
4
United
States,
the
fossil
fuel
CO,
emissions
from
cars
and
light
trucks
are
higher
than
the
total
nationwide
CO,
emissions
from
all
but
three
other
countries
(China,

Russia,
and
Japan).
'

This
anthropogenic
forcing
of
clinlate
change
will
affect
not
only
the
environment,
but
will
also
significantly
impact
human
health.
At
a
conference
on
Human
Health
and
Global
Climate
Change,
cosponsored
by
the
National
Science
and
Technolorn
Council
and
the
I'dstitute
of
Medicine,
Vice
President
Al
Gore
outlined
the
potential
health
risks
caused
by
global
walming
and
stated
that
measures
must
be
taken
to
safeguard
the
American
people."
Additionally,
the
conference
participants
stated
that
the
lack
of
complete
data
on
this
issue
should
not
be
used
as
an
excuse
for
inaction."
Instead,
the
participants
urged
governments
to
apply
the
precautionary
principle
to
its
decision
making
concerning
globa1,
warming.
l2
Embodied
in
this
request
is
an
understanding
that
­

the
tremendous
potential
risks
to
public
health
posed
by
global
warming
dictate
that
governments
must
act
with
precaution
and
take
all
prudent
steps
necessary
8
U.
S.
Department
of
Energy,
TECHNOLOGY
OPPORTUNITIES
TO
REDUCE
U.
S.
GREENHOUSE
GAS
ElMISSIONS,
xiii
(Oct.
1997).

9
John
DeCicco
and
Marlin
Thomas,
GREEN
GUIDE
TO
CARS
AND
TRUCKS,
2
(1999).

l
o
The
Conference
on
Human
Health
and
Global
Climate
Change,
September
11,
1995,
at
4
[hereinafter
Conference
on
Human
Health
and
Global
Cli~
nate
Change,
Pet.
Ex.
21.

1
1
­
Id.
at
1.

Int'l.
C
t
r
.
for
Tech.
Assm't.
Legal
Petition
to
EPA
­
October
20,1999
....

....
...

..
,
.
,_
.
,
I
..
.
,
.
:­.
­
.
.
:
%
..
....
..........
..
.......
..,.
­
.­
....
...
..
....
.........
...
......
..
i
­
­
`,"­

to
reduce
the
emission
of
anthropogenic
greenhouse
gases.

Within
the
context
of
United
States
governmental
decision
making:
the
precautionq
principle
is
embraced
by
the
Clean
AirAct
("
CAA"),
a
statute
allowing
for
the
implementation
of
a
regulatory
framework
mandating
the
reduction
of
greenhouse
gases.
Under
the
CAA,
the
Administrator
is
pennitted
to
nlalre
a
precautional?
decision
to
regulate
pollutants
in
order
to
protect
public
health
and
~e1fare.
l~
In
addition
to
the
precautionary
nature
of
the
CAA,
the
Administrator
has
a
mandatory
duty
to
regulate
greenhouse
gas
emissions
from
new
motor
vehicles
under
202(
a)(
l)
of
the
CAA.
Petitioners
urge
the
Administrator
to
reduce
the
effects
idf
global
warnling
by
regulating
the
emission
I
of
greenhouse
gases
from
new
motor
vehicles.
4
­

ARGUMENT
I.
GREENHOUSE
GAS
EVISSIONS
FROM
NEW
MOTOR
VEHICLES
MUST
BE
REGULATED
UNDER
Q
202(
a.[
l)
OF
THE
CLEAN
ATR
ACT.

Under
5
202(
a)(
l)
of
the
Clean
Air
Act,
42
U.
S.
C.
5
7521(
a)(
1),
the
Administrator
is
directed
to
prescribe
standards
for
the
emission
of
greenhouse
gases
from
new
motor
vehiclesI4
if
she
has
determined
that:
(1)
the
emission
of
a
.
greenhouse
gas
is
an
"air
pollutant"
and
is
emitted
from
new
motor
vehicles;
and
[Z)
the
emission
causes
or
contributes
to
air
pollution
which
may
reasonably
be
anticipated
to
endanger
public
health
or
welfare.
For
the
.reasons
contained
herein,
the
Administrator
has
made
such
determinations
.for
greenhouse
gases,

I
?
­
See
H.
R.
Rep.
No.
291,
95:
'
Conp..
i'!
Sess.
49
(1
4
i
i
).

I'
Section
202
applies
to
new
motor
vehicles
and
new
motor
vehicle
engines.
Hereinafter,
petitioners'
reference
t
o
"neiv
motor
vehicles"
also
applies
to
"new
motor
vehicle
engines."

Int`
l.
Ctr.
for
Tech.
Assm`
t.
Legal
Petition
to
EPA
­
Octobcr
20,1999
9
...

..

..
.........
..
...
.......
...
­.
.
....
.......
".
.
..
..
,/
/

­\
I
".
,

including
CO,,
CH,,
N,
O,
and
HFCs.
and
petitioners
request
the
Administrator
to
undertake
her
mandatory
duty
to
regulate
these
as
directed
by
$ZOZ(
a)(
l)
of
the
CAA.
a
*
­

A.
Greenhouse
Gases
Meet
The
Definition
Of
'Rir
Pollutant"
Under
The
Clean
Air
Act
And
Are
Emitted
From
New
Motor
Vehicles.

Pursuant
to
5
302(
g),
42
U.
S.
C.
5
7602(
g),
of
the
CAA,
an
"air
pollutant"
is
defined
as:

any
air
pollutant
agent
or
combination
of
such
agents
including
any
physical,$
hemical,
biological,
radioactive
(including
source
material,
special
nuclear
material,
and
byproduct
material)
substance
or
matter
which
is
emitted
into
or
othenvise
enters
ambient
air.
Such
term
includes
any
precursors
to
the
formation
of
any
air
pollutant,
to
the
extent
the
Administrator
had
identified
­

such
precursors
or
precursors
for
the
particular
purpose
for
which
the
term
"airpollutant"
is
used.
..
Courts
have
interpreted
this
definition
in
an
extremely
broad
manner.
15
The
greenhouse
gas
emissions
that.
the
petitioners
request
the
Administrator
to
regulate
under
5
202(
a)(
l)
meet
the
CAA's
broad
statutory
definition
of
"air
pollutant"
and
are
emitted
from
new
motor
vehicles.

(1)
Emission
of
Carbon
Dioxide
Carbon
dioxide
(CO,)
meets
the
5
3
0
2
0
definition.
Over
the
last
several
decades,
levels
of
CO,
emissions
have
sharply
risen
causing
the
natural
equilibrium
of
emissions
and
absorption
to
fall
out
of
balance.
Although
CO,
is
I5
Alabama
Power
Co..
Y.
Costle.
636
F.
2d
323,353
(D.
C.
Cir.
1979).

Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
t
o
EPA
­
October
20,1999
10
.­
.
.
­
..

..
.
.
­.
..
­
.
~..
~.
.
.
.
.
..
.
..
..
..
eo,
levels
and
disrupted
this
natural
equilibrium.
I6
In
fact,
the
U.
S.
Climate
4
4
Action
Report's
"Greenhouse
Inventory,"
submitted
under
the
United
Nations
Framework
Convention
on
Climate
Change,
states
that
CO,
is
considered
the
most.
significant
greenhouse
gas
in
the
U.
S.
because
it
encompasses
eighty­
five
percent
of
the
total
U.
S.
greenhouse
gas
emissions.
l7
Due
to
the
global
warnling
dangers
connected
with
the
high
emissions
of
CO,,
this
greenhouse
gas
satisfies
the
definition
of
"air
pollutant"
under
the
C
M
.
­

Additionally,
mobile
sources
emit
significant
amounts
of
CO,.
The
transportation
sector
contributes
over
30%
of
U.
S.
greenhouse
gas
CO,
emissions
from
fossil
fuel
combustion.
''
Alrhbst
two­
thirds
of
the
emissions
come
from
automobiles
and
the
remaining
emissions
come
from
trucks
and
aircraft.
19
The
greenhouse
gas
emissions
from
transportation
sources
are
predicted
to
grow
faster
than
any
other
emission
source.
2o
­

Finally,
the
agency
has
already
made
a
legal
determination
that
CO,
meets
the
definition
contained
in
3
302(
9).
In
an
April
10,
1998,
memorandum
t
o
the
Administrator,
EPA
General
Counsel
Jonathan
2.
Cannon
found
that
the
broad
definition
of
5
302(
g)
"states
that
.'air
pollutant'
includes
any
physical,
chemical
biological,
or
radioactive
substance
or
matter
that
is
emitted
into
or
othenvise
enters
ambient
air.
SO,,
NO,,
CO,
and
mercury
from
electric
power
generation
are
each
a
.
"physical
[and]
chemical
.
.
.
substance
which
is
emitted
into
.
.
.
the
ambient
air,"
and
hence,
each
is
an
air
pollutant
within
the
meaning
ofthe
Clean
..

l6
'
Greenhouse
Gas
Inventory.
U.
S.
Climate
Action
Report
7
(I
997)
[hereinafter
U.
S.
Climate
Action
Report,
Ex.
31.

17
­
Id.

IS
Department
of
Enerpy:
Reducing
Greenhouse
Transportation
Sector
Emissions,
l
~~t
p
://w
t
v
~~.e
s
d
.o
~~~l
.~o
v
/b
~~p
i
b
i
o
~~i
~~~r
~~l
u
c
i
n
~.h
~~~~i
.

19
U.
S.
Climare
Action
Report,
Ex.
3
at.
S.

­
Id.
20
Int'l.
Ctr.
for
Tech.
Assnl't.
Legal
Petition
to
EPX
­
Octoher
20,1999
11
MI­
Act."
21
The
memorandum
further
notes
that
Congress
explicitly
recognized
CO,
emissions
as
an
"air
pollutant"
under
3
103Ig)
of
the
Clean
Air
Recently,
EPA
again
made
this
legal
determination
during
hearings
before
Congress.
23
4
a
­

(2)
Emission
of
Methane
Methane
(CH,)
should
also
be
considered
an
"air
pollutant"
under
3
302(
g)

of
the
CAA
because
of
its
contribution
to
global
warning.
The
U.
S.
Climate
Action
Report
indicates
that
CH,
"is
estimated
to
be
twenty­
one
times
more
effective
at
trapping
heat
in
the
drnosphere
than
CO,
over
a
100­
year
time
horizon."
24
During
the
past
two
centuries,
CH,
concentrations
have
more
than
doubled
due
to
human
a~
tivities.~~
Because
CH,
is
a
potent
greenhouse
gas,
it
satisfies
the
definition
of
"air
pollutant"
under
the
CAA.
Furthermore,
motor
vehicles
fueled
by
gasoline
emit
CH,.
The
EPAs
most
recent
inventory
of
greenhouse
gas
emissions
indica&
that
in
1997
gasoline
powered
cars,
trucks,

and
heavy­
duty
vehicles
emitted
1.2
MMTCE
of
CH,
26
­

21
Johnathan
Z.
Cannon,
Memorandum
toCarol
M.
Browner,
Adminsitrator,
"EPA's
Authority
to
Regulate
Pollutants
Emitted
by
Electric
Power
Generation
Sources."
(April
10,
1998).

22
­
Id.

23
.
Testimony
of
Gary
S.
Guzy,
General
Counsel,
U.
S.
E.
P.
A.,
before
a
Joint
Heaing
of
the
Subcornmitttee
on
National
Economic
Growth,
Natural
Resurces
and
Regulatory
Affairs
of
the
Committee
on
Government
Refornl
and
the
Subcommittee
on
Energy
and
Environment
of
the
Committee
on
Science,
United
States
House
of
Representatives.
(October
6,
1999).

26
EPA,
Inventorv
of
US.
Greenhouse
Gas
Emissions
and
Sinks:
1990­
1997.36
(Mar.
1999).

Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
to
EPA
­
October10,1999
..

......
..
­
...
....
12
,/
i
I
/
e.

(3)
Emission
of
Nitrous
Oxide
Nitrous
oxide
(N20)
is
a
greenhouse
gas
that
is
produced
naturally
by
biological
s
k
r
c
e
s
in
soil
and
water.
,However,
over
the
past
two
centuries,
N,
O
levels
have
increased
by
eight
percent
due
to
human
activities.
27
The
U.
S.

Climate
Action
Report
explains
that
``[
wlhile
N20
emissions
[sic]
are
much
lower
than
CO,
emissions,
N,
O
is
approximately
3
10
times
more
powerful
than
CO,
at
trapping
heat
in
the
atmosphere
over
a
100­
year
hori~
on."~~
As
a
result,
N,
O
meets
the
CAA
definition
of
"air
pollutant."
b
`

This
greenhouse
gas
is
also
emitted
from
motor
vehicles
during
fossil
fL1el
cornbu~
tion.~~
Due
to
the
installati+
of
catalytic
converters,
a
device
designed
to
reduce
air
pollution,
the
volume
of
N20
emitted
from
motor
vehicles
has
1­
isen.
3~

(4)
Emission
of
Hydrofluorocarbons
Hydrofluorocarbons
(HFCs)
is
a
powerful
greenhouse
gas
that
meetsthe
,

definition
of
"air
pollutant"
under
th'e
CAA.
HFCs
were
introduced
as
alternatives
to
chlorofluorocarbons,
which
aie
ozone
depleting
s
~b
s
t
a
n
c
e
.~'
Although
these
gases
do
not
directly
destroy
ozone,
they
do
contribute
to
global
~m
r
m
i
n
g
.~~
HFCs
impact
the
ambient
air
by
contributing
to
global
warning
as
much
as
10,000
times
that
of
C0,.
33
The
emissions
of
HFCs
from
motor
vehicles
have
increased
.*

27
U.
S.
Climate
Action
Report,
Ex.
3
at
13.

..
11
­
Id.

Int'l.
Ctr.
for
Tech.
Assm't.
Legnl
Petition
to
EPA
­
Oclober
20,
1999
13
since
1993
due
to
the
use
of
HFC­
134a
in
mobile
air
~0nditioner.
s.~~
­

As
discussed
above,
the
four
greenhouse
gases
subject
to
this
petition
have
been
detei­
mined
to
accelerate
global
warming.
Additionally,
the
agency
has
already
made
the
determination
that
CO,
is
an
"air
po1lutant"
as
defined
under
the
C
M
.
Accordingly,
similar
determinations
that
the
emissions
of
CH,,
N,
O,
and
HFCs
from
motor
vehicles
also
meet
the
definition
of
"air
pollutant"
under
5
302(
g)

of
the
CAA
follow.

B.
The
Emission
Of
G
r
e
e
n
h
o
d
Gases
Contributes
To
Pollution
Which
IS
Reasonably
Anticipated
To
Endanger
Public
Health
And
Welfare.

Pursuant
to
the
requirements
of
§202(
a)(
11,
greenhouse
gas
emissions
from
new
motor
vehicles
must
also
be
regulated
under
the
CAA
because
of
their
endangemlent
to
public
health
or
welfare.
When
determining
what
constitutes
an
endangerment
to
public
health
and
welfare,
the
CAA
does
not
require
proof
of
actual
harm.
Instead,
the
Administrator
is
permitted
to
make
a
precautionary
decision
to
regulate
a
pollutant
if
it
"may
reasonably
be
anticipated".
to
endanger
public
health
or
welfare.
35
This
requirement
is
confirmed
by
the
CAA's
legislative
history.
The
House
Report
accompanying
the
1977
Anvmdrnents
states
that
one
of
the
CAA's
purposes
is
"Itlo
emphasize
the
preventive
or
precautionary
nature
of
the
act,
i.
e.,
to
assure
that
regulatory
action
can
effectively
prevent
harm
before
it
occurs;
to
emphasize
the
predominant
value
of
protection
of
public
health."
36
As
,.

3­
1
U.
S.
Climate
Action
Report,
Ex.
3
at
16.

..
Engine
Mfr.
Ass'n
v.
EPA,
85
F.
3d
1075,
1099
(D.
C.
Cir.
1996):
See
also,
Lead
Industries
Assoc.,
647
15
F.
2d
at
I156
(explaining
that
the
1977
CAA
amendments
made
the
threshold
decision
to
regulate
air
pollutants
p
w
w
i
u
1
I
.q
i
r
l
~~`t
~u
r
e
.~.

H.
R.
Rep.
No.
294.
95th
Cong.,
1st
Sess.
49
(1977)(
stn!
inp
that
Congress
used
the
phrase
"may
reasonably
be
anticipated
to
endanger
public
health
or
welfare"
to
emphasize
the
precautionan.
nature
of
the
CAA.
This
phrase
is
present
i
n
sections
lOS,
11
1,
112,
202,
21
1,
and
231
.>

Int`
l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
to
EPX
­
Octoher
20,1999
14
..
.
..

­
..
..
.
­.
.
­­
_­.
.
..

..
..
.
.
­
._
."
i".
..
..
­
..
.
._...
..
.
.
..
enumerated
below,
the
EPA
and
other
federal
agencies
have
already
made
numerous
findings
that
greenhouse
gas
emissions
from
new
motor
vehicles
are
air
pollutafits
reasonably
anticipated
to
endanger
public
health
and
welfare.

Therefore,
the
Administrator
has
the
statutory
obligation
to
regulate
the
emissions
of
air
pollutants
from
new
motor
vehicles
under
5
202(
a)[
l)
in
order
to
prevent
future
harm.
a
'

(1).
The
Emission
of
Greenhouse
Gases
Will
Endanger
Public
Health.

The
IPCC
reports
that
greenhouse
gas
emissions
are
significantly
accelerating
current
warming
trends
and
estimates
that
by
the
year
2100,
the
Earth's
temperature
will
have
changed
by
two
degrees
Cel~
ius.~
'
As
a
result
of
increased
temperatures,
the
EPA
reports
that
certain
infectious
diseases
may
become
more
prevalent
in
geographic
areas
that
were
once
free
from
the
threat
of
such
diseases.
38
In
particular,
glohal
walming
may
increase
vector­
born
diseases
such
as
malaria,
dengue
fever,
encephalitis,
and
hantavirus
alongwith
increasing
water­
born
diseases
such
as
choiera,
toxic
algae,
and
cryptosporidiosis.
Changing
climate
conditions
will
also
increase
the
likelihood
of
direct
effects
on
human
health,
including
heat
stress,
skin
cancer,
cataracts,
and
immune
suppression.
­

(a).
GlobalWarming
Increases
the
Threat
of
Infectious
Diseases.

1.
Increases
in
Vector­
borne
Diseases.

Infectious
diseases
kill
over
seventeen
million
people
each
year.
39
Vector­

borne
diseases,
usually
caused
by
a
microbial,
insect
or
small
mammal
vector,

37
Jonathan
A.
Patz,
Public
Health
Effects
of
Climate
Change
Svnthesis
of
the
IPCC
Findings,
2
(i
996)
[i~
cIci~~
ai'tcI
FCC,
EL
41.

Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
to
EPA
­October
20,1999
15
..
cause
a
large
portion
of
those
fatalities4'
The
spread
of
vector­
borne
diseases
is
a
serious
concern
because
disease
vectors
are
sensitive
to
climate
variation&
41
e
*

Malaza
is
the
most
prevalent
vector­
born
disease.
Although
this
disease
generally
occurs
in
the
tropics
and
subtropics,
the
U.
S.
i
s
not
immune
from
this
disease
as
indicated
by
the
latest
Center
for
Disease
Control
(``
CDC")
report.
42
The
CDC
reports
a
15%
increase
in
cases
of
malaria
in
the
U.
S
from
1994
th1­
u
1995.43
Unseasonably
waml
weather
increases
the
transmission
of
malaria.

Consequently,
the
IPCC
reports
that
more
than
one
million
additional
fatalities
from
malaria
is
estimated
to
occur
by
the
middle
of
the
next
century
due
to
global
\varming.
44
3
Dengue
and
Dengue
hemomhagic
fever
is
a
painful
flu­
like
illness
transmitted
by
a
mosquito
bite
that
is
increasing
not
only
in
the
tropics,
but
also
in
the
Americas.
45
Warmer
temperatures
contribute
to
the
spreading
of
this
disease
to
higher
latitudes
and
altitudes.
46
In
fact,
dengue
was
"observed
in
Mexico
at
an
unprecedented
altit;
Ghe
of
1,700
meters
during
an
unseasonably
warm
summer
in
1988."
47
The
'IPCC
report
states
that,
when
temperatures
­

..

­
Id.
at
Table
18­
3
(data
on
the
diseases
that
are
likely
to
be
affected
by
climate
change).

41
­
Id.
at
7.

43
Malaria
Surveillance
­
United
States,
1995,

44
IPCC,
Ex.
4
at
8.

­
12.
45
Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
to
EPA
­
October
20,
1999
16
...
..
...
.....
....
..
........
......
...
..........
.......
........
..
..
.~
....
..
.....
"
..
~
..
­
..
.
"
I
/

i
'
:­
I
h
increase,
more
infectious
mosquitos
hatch
resulting
in
more
people
being
bitten.
4s
Arboviral
encephalitis
is
another
vector­
borne
disease
that
is
highly
correlated
towarm
temperatures.
.Outbreaks
of
this
disease
have
occurred
in
the
U.
S.
after
several
clays
when
the
temperature
exceeded
eighq­
five
degrees
F
a
h
r
e
n
l
~e
i
t
.~~
Heavy
rainfall
during
winter
months
and
drought
during
summer
months
is
another
predictor
for
this
disease.
The
effect
of
global
climate
change
predicted
fox­
the
U.
S.
is
warnl,
wet
winters
and
hot,
dry
summers.
These
conditions
foster
an
environment
for
the
spread
of
arboviral
en~
eph,
alitis.~~
a
*

Hantavirus
is
a
deadly
infectious
disease
caused
by
infected
deer
mice
or
cotton
rats.
51
The
CDC
reported
an
aftltbreak
of
this
illness
in
the
southwest
U.
S
in
1993.52
This
epidemic
occurred
when
six
years
of
drought
preceded
heavy
spring
rains.
53
This
ecological
change
resulted
in
an
increase
of
the
rodent
population
ten
times
its
normal
size
and,
consequently,
caused
the
outbreak
of
hanta~
i­
irus.~~
Reports
of
this
disease
have
occurred
in
the
western
U.
S.
and
in.
a
few
eastern
­

,.
.*

49
Jonathan
A.
Patz
and
Paul
R.
Epstein,
et
al.,
Global
Climate
Chance
and
Emercine
Infectious
Diseases.
JAMA
219­
220
(1996)
[hereinafter
JAMA].

­
Id.
at
220.

51
Center
for
Disease
Control,
Hantavirus,
Public
Information
area,
http://
www.
cdc.
gov/
ncidod/
diseaseslhant~
ps/
nofr~
mes/
consumer.
htm.

52
JAMA,
at
2
17.

'j
.
Center
for
Disease
Control,
HPS
Case
Information,
h
t
t
p
://w
w
n
..c
d
c
..o
v
l
n
c
i
d
o
d
l
d
i
s
e
n
s
e
s
/h
a
n
.h
t
m
.

Int'l.
Ctr.
for
Tech.
Assnl't.
Legal
Petitiun
to
EPA
­
October
20,1939
17
/
/

/
,
,,"
'
­.

2.
Increases
in
Water­
borne
Diseases.
­
During
the
past
century,
sea
surface
temperatures
have
increased
0.7
degrees
C
e
i
s
s
i
~s
.~~
Increased
temperature
and
nutrient
water
promotes
the
growth
of
toxic
algae.
5'
Toxic
algae
is
dangerous
because
it
causes
shell­
fish
poisoning
which
may
h
a
m
humans,
sea
mammals,
and
sea
birds.
58
4
'

Increased
algae
growth
can
also
stimulate
the
incidence
of
cholera.

Zooplankton
feeds
on
algae
and
can
serve
as
a
reservoir
for
Vibrio
ch01el­
a.~~

Increased
algae
blooms
may
increase
the
proliferation
of
a
cholera
epidemic.
In
Latin
America,
large
coastal
algae
blooms
are
suspected
to
have
perpetuated
a
cholera
epidemic.
60
The
IPCC
repod
that
cholera
may
increase
in
the
U.
S.
as
sea
temperatures
increase.
61
The
most
widespread
waterborne
disease
in
the
US.
is
cryptosporidiosis.
62
This
disease
occurs
when
floods,
heavy
rains,
and
snow
melts
cause
run­
off
on
agricultural
dairy
farrns
contaminating
the
water.
63
For
example,
in
1993,

Milwaukee
reported
403,000
cas&
'of
this
disease
after
experiencing
unusually
heavy
spring
rains
and
melting
Rising
sea
levels
will
also
affect
the
spread
­

..

56
IPCC,
Ex.
4
at
8.

57
JAMA
at
220
(nutrient
waters
develop
from
fertilizer
runoff
and
sewage
releases).

5s
­
Id.
and
IPCC,
Ex.
4
at
12
(explaining
that
a
species
of
toxic
algae
that
was
previously
confitled
to
the
Gulf
of
Mexico
traveled
north
after
"a
parcel
of
warm
gulf
stream
water"
rose
up
the
east
coast
and
the
result
was
human
shellfish
poisonings
and
substantial
fishkills).

59
IPCC,
Ex.
4
at
8.

­
Id.
60
61
­
Id
at
12.

63
IPCC,
Ex.
4
at
12.

Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
t
o
EPX
­
October
20,1999
18
...
"

..
.........
..
...
­.
..
......
..
I
.

..
,
.?
,
F.
i
of
this
disease
because
saline
water
extends
the
viability
of
this
disease.
65
Thus,
significant
research
has
shown
that
climate
change
affects
the
spyead
of
numeroas
and
life­
threatening
vector­
borne
and
water­
borne
diseases.
TO
8
protect
public
health
by
reducing
the
threat
and
spread
of
these
diseases,
EPA
must
immediately
regulate
the
emissions
of
greenhouse
gases
from
new
motor
vehicles
under
5
202(
a)(
l).

(b).
Global
Warming
Will
Have
Direct
Effects
on
Human
Health.

1.
Increases
in
Heat
Stress.

The
EPA
reports
that
"the
mo2t
direct
effect
of
climate
change
would
be
the
impacts
of
hotter
Hotter
temperatures
affect
the
young,
the
elderly,
and
people
with
heart
problems
and
causes
increased
cases
of
heat
exhaustion,
respiratory
problems,
and
even
death.
67
The
IPCC
reports
that
the
U.
S.
is
expected
to
``
warm
disproportionately
more
than
tropical
and,
subtropical
The
effects
from
this
temperature
increase
can
be
determined
by
reviewing­
data
from
past
heat
waves.
The
IPCC
explains
that
data
taken
from
Philadelphia
during
1973
to
1988
shows
that
there
is
a
relationship
between
temperature,
humidity,
and
rn~
rtality.~
'
Based
on
data
taken
from
several
North
Arnerican
cities,
the
IPCC
predicts
that
"the
annual
number
of
heat­
related
deaths
would
approximately
double
by
2020
and
would
increase
6s
­
Id.

66
EPA,
global
warming,
http://
www.
epa.
go~/
globalwarmin~
i~
npacts~
ealth/
index.
ht~~.

15'
Id.
(explaining
that
higher
temperatures
increase
ozone
at
ground
level
which
can
cause
respiratory
problems)
and
see
Conference
on
Human
Health
and
Global
Climate
Change,
Ex.
2
at
9
(reporting
that
726
people
dicd
i
n
1995
durins
n
heawave
i
n
Chicaso).

IPCC,
Ex.
4
at
1
1.
­

65
Int'l.
Ctr.
for
Tech.
Assnl't.
Legal
Petition
to
EPA
­
October
20,1999
19
.
"
.
..
­
.~
.
.~

..........
..
..
,/
,
*/
'

I
­
_­

several­
fold
by
2050."
70
­

­
2.
Increases
in
Skin
Cancer,
Cataracts,
and
Immune
Suppression.

Greenhouse
gases
prevent
heat
from
entering
the
stratosphere.
As
a
result,

ice
clystal
fornlations
increase
in
the
upper
stratosphere
destroying
the
ozone
laye~­.~
l
Ozone
destruction
increases
the
amount
of
ultraviolet­
B
radiation
entering
the
earth's
surface,
which
impacts
public
health
by
directly
contributing
to
skin
cancer,
cataracts,
and
immune
suppression.

A
CDC
report
indicates
that
most
of
the
top
ten
cancers
declined
between
1990
and
1995
except
for
inciden'ce
of
skin
cancer.
72
Skin
cancer
is
the
most
common
cancer
in
the
U
S
and
the
incidence
of
melanoma
has
doubled
since
1973.
'3
The
U.
S.
National
Cancer
Institute
explains
that
"[
nlearly
all
skin
cancers
occur
in
fair­
skinned
individuals
who
have
been
exposed
to
the
sun,
x­
rays,
or
ultraviolet
light
for
prolonged
periods."
'*
The
participants
at
the
Conference
on
Human
Health
and
Global
Climat­
Change
predict
that
skin
cancer
will
increase
tsvo
percent
for
every
one
percent
decrease
in
stratospheric
o~
one.
'~
­

Ultraviolet
B­
radiation
is
also
associated
with
the
development
of
cataracts.

'O
­
Id.

71
­
Id.
at
10.

Center
for
Disease
Control,
1998
News
Release,
12
l
~t
t
~:/l
w
~v
~~~.c
d
c
.~o
~l
/n
c
h
s
~~~~~~l
r
~l
~~s
~s
~9
S
n
e
~v
s
l
9
S
n
e
w
s
l
c
a
n
c
e
r
.l
~t
m
72
American
Cancer
Society,
Skin
Cancer
­
Melanoma,
http:
l/
w~~
w3.
cancer.
or9/
cancerinfo/
mni1~
cont,
asp?
st=
wi&
ct=
jO.

73
Conference
on
Human
Health
and
Global
Climate
Change,
Ex.
2
at
12,

Int'l.
Ctr.
for
Tech.
Assm't.
Legnl
Petition
to
EPA
­
October
20,1999
20
,/
,

.­
i
_I
Half
of
the
blindness
in
the
world
is
attributed
to
~ataracts.
'~
IPCC
predicts
that
a
ten
percent
loss
of
stratospheric
ozone
will
result
in
approximately
1.7
million
additional
cases
of
cataracts
1
`

Inlmune
suppression
is
also
a
direct
effect
from
global
warming.
The
Ipcc
report
states
that
"UV
light
has
been
shown
to
cause
immune
suppression
in
both
animal
and
human
studies."`
S
Immunosuppression
decreases
the
strength
of
the
human
immune
system.

Therefore,
the
human
health
effects
of
climate
change
\vi11
also
be
exacerbated
by
increasing
humans'
susceptibility
to
heat
stress,
skin
cancer,
and
cataracts.
These
direct
threats
to
p'tiblic
health
immediately
mandate
the
EPA
to
regulate
the
emissions
of
greenhouse
gases
from
new
motor
vehicles
under
5
202(
a)
(1).

­

@I.
The
Emission
of
Greenhouse
Gases
Will
Endanger
PubZic
Welfare.

In.
addition
to
endangering
public
health,
the
emission
of
greenhouses
gases
1.

will
also
harm
the
public
welfare:
Under
the
CAA,
public
"welfare"
is
defined
as:

All
language
referring
to
effects
on
welfare
includes,
but
is
not
limited
to,
effects
on
soils,
water,
crops,
vegetation,
manmade
materials,
animals,
wildlife,
weather,
visibility,
and
climate,
damage
to
and
deterioration
of
property,
and
hazards
to
transportation,
as
well
as
effects
on
economic
values
and
on
personal
comfort
and
well­
being,
whether
caused
by
transformation,
conversion,
or
combination
with
other
air
pollutant^.^
'

76
IPCC,
Ex.
4
at
IO.

­
Id.

­
Id.
77
7s
79
42
U.
S.
C.
3
7602(
h)(
emphasis
added);
See,
Engine
iWr.
Ass'n.
85
F.
3d
at
1099
(Reaffirming
the
broad
authority
of
the
Administrator
to
make
this
determination).

Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
to
EP.
A
­
Oclober
20,
1999
There
have
been
numerous
EPA
findings
that
greenhouse
gas
emissions
will
endanger
"public
welfare"
as
defined
by
this
section
of
the
CAA.
In
fact,
the
EPA
e
has
research­
ed
the
potential
environmental
impacts
from
climate
change
and
*

reports
that
global
warming
will
significantly
harm
the
environment.

(a),
Global
Warming
Will
Harm
Environmental
Welfare.

The
emission
of
greenhouse
gases
and
the
consequential
effects
of
global
warming
will
severely
h
a
m
the
quality
of
the
United
States
environment.
Global
warming
will
harm,
inter
alia,
water
resources,
rangelands,
forests,
non­
tidal
wetlands,
fisheries
and
birds.
.d
1.
Harm
to
Water
Resources.

Evaporation
and
precipitation
is
expected
to
increase
due
to
global
warning.

The
EPA
predicts
that
``[
l]
ower
river
flows
and
lower
lake
levels
could
imfair
navigation,
hydroelectric
power
generation,
and
water
quality,
and
reduce
the
supplies
of
water
available
for
agriculture,
residential,
and
industrial
uses.
''80
Furthermore,
increased
rainfall
will
likely
result
in
flooding.
81
2.
Harm
to
Rangelands
and
Forests.

Global
warming
willlikely
harm
grazing
activities
on
both
federal
and
private
lands.
The
EPA
predicts
the
decrease
in
the
availability
of
water
in
these
areas
will
ham
the
economic
viability
of
grazing
on
rangelands.
62
As
temperatures
increase,
many
North
American
forests
will
shift
to
the
s2
Id.
at
http://
w~
v~~.
epa.~
o~/
globalwarn~
ing/
impactslranpelands/
index.
html.
­

Int'i.
Ctr.
for
Tech.
Assm't.
Legni
Petition
to
EPh
­
0ctol)
er
20,1999
22
..
.­

,..
.
..
.
..
.
..
.
..
.
."
..
.
.
.
.
.­
.~.
..
­.
.
..
.­

..
.
..
i
north.
s3
Tfie
distance
that
trees
will
have
to
migrate
will
depend
on
how
fast
temperatures
increase.
s4
As
temperatures
increase,
the
soil
will
become
>riel­,

which
tvill
escalate
the
likelihood
of
forest
fires?
Also,
changes
in
pest
4
­

populations
will
negatively
affect
the
survival
of
forests.
SG
Furthernore,
the
EPA
reports
that
wildlife
that
depend
on
the
habitat
of
nature
reserves
may
be
vulnerable
because
these
areas
may
no
longer
be
located
ina
climate
suitable
for
the
S
L
I
~~V
~I
of
many
speciess7
3.
Hwm
to
Non­
tidal
Wetlands.

Wetlands
serve
several
purpbkes
in
protecting
the
environment.
\Vetlands
provjide
a
habitat
for
birds
and
fish
and
also
prevent
run­
off
pollution
from
falms
and
other
sources
from
entering
rivers,
lakes,
and
streams.
8s
The
EPA
explains
that
the
impact
on
wetlands
from
changing
climate
is
uncertain
because
it
­
depends
on
the
amount
of
rainfall
received
by
vetl
land^.^^
If
wetland
areas
receive
a
decrease
in
rainfall,
then
the
arc&
will
become
drier
and
significantly
impair
the
wetland's
f
~~n
c
t
i
o
n
.~~
Dry
land
will
force
fanners
to
increase
their
use
of
irrigation
which
may
further
drain
wetland^.^
'
If
the
wetland
areas
receive
an
increase
in
83
Id.
at
http://
www.
epa.
gov/
elobalwarmin~
impacts/
forests/
index.
html.
­

S­
1
Id.
(EPA
recognizes
the
uncertainties
that
exist
pertaining
to
changing
climate
and
migrating
forests)
.
­

86
­
Id.

­
Id.
87
83
­
Id.
at
hltp:
Nwww.
epa.
gov/
plobal\~
arminp/
impa~
ts/~
vet~
an~
s/
index.
ht~.

­
It!.
89
Int'l.
Ctr.
for
Tech.
Assm'f.
Lcgnl
Petition
to
EPA
­
Octoher
20,1999
23
..
..
.
..
.
..
/
I?
.­
­.

rainfall,
then
flooding
will
occur.
92
Flooding
will
force
people
to
move
out
of
hazardous
areas,
which
will
benefit
wetlands
by
allowing
them
to
form.
HoIVever,

if
people
build
dams
in
order
to
prevent
flooding,
which
is
likely,
then
the
new
structures,
along
with
the
decrease
in
flooding,
will
prevent
wetlands
from
forming.
93
I
8
4.
Harm
to
Fisheries.

The
EPA
reports
that
climate
change
may
impact
inland
fisheries,
coastal
fisheries,
and
ocean
fi~
heries.
'~
Increased
water
temperatures
may
be
too
warm
for
some
species
of
fish.
gJ
Global
mhxiing
might
also
harm
many
species
of
fish
by
changing
the
chemical
composition
of
the
water
by
decreasing
the
amount
of
oxygen
and
increasing
the
pollution
and
salinity
level?
Species
that
are
dependent
on
wetlands
for
habitat
and
food
would
also
be
hamed
if
wetlands
de~
rease.
'~
­

5.
H
a
m
to
Bird
Popdations.

Global
warming
may
impact
birds
by
altering
their
life
cycles.
The
National
Audubon
Society's
bird
data
reveals
that,
during
warming
years,
birds
do
not
fly
as
far
south
and
during
the
summer
months,
birds
fly
farther
north.
98
The
EPA
indicates
that
this
change
in
migration
may
be
harmful
to
birds
because
the
92
­
Id.

­
Id.
93
94
EPA.,
Global
Warming.
hltp://
www.
epa.
pov/~
loba~~~
armin~
impacts/
fisheries/
inde.
u.
ht~~~.

95
­
Id.

­
id.
96
91
­
Id.

Int`
l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
t
o
EPA
­
October
20,
1999
24
vegetation
and
insects
they
rely
upon
may
take
decades
to
synchronize
with
the
birds'
change
in
m
i
g
r
a
t
i
~n
.~~
­

S
I
­
Additionally,
habitat
loss
due
to
global
Ivarming
%vi11
impact
many
bird
species.
Rising
sea
levels
will
decrease
estuarine
beaches,
which
are
habitats
for
the
least
tern,
an
endangered
species."
'
The
loss
of
wetlands
and
decreasing
shellfish
levels
\vi11
also
impact
many
species.
lo'

As
discussed
above,
EPA
recognizes
that
the
environmental
welfare
of
the
United
States
is
impacted
by
the
emission
of
greenhouse
gases
and
the
effects
of
global
n­
arnling.
The
impacts
include,
inter
alia,
direct
ham1
to
our
water
resources,
rangelancls,
forests,
non­
tidal
a
wetlands,
fisheries,
and
birds.
Although
there
may
be
some
uncertainties
concerning
the
extent
of
these
impacts
from
global
warming,
EPA
must
exercise
precaution
and
mitigate
these
impacts
by
regulating
the
emissions
of
greenhouse
gases
from
new
motor
vehicles
un&
r
5
202(
a)(
1)
of
the
CAA.
,.

.i
(b).
Global
Warming
Will
Harm
Human
Welfare.

The
emission
of
greenhouse
gases
and
resulting
global
warming
will
also
severely
ham
the
human
welfare
of
the
United
States'
population.
Global
warming
will
harm,
inter­
alia,
food
production,
nutritional
health,
weather
pattems,
sea­
levels,
water
quality
and
quantity,
and
respiratory
health.

Int'l.
Ctr.
for
Tech.
Assm't.
Legal
l'etition
Io
EPA
­
Octoher
20,1999
25
i
,i
1.
Harm
to
Food
Production
and
NutritionaZ'HeaZth.
­
Global
warming
is
expected
to
change
crop
productivity.
'02
Agricultural
productivity
may
increase
in
some
regions
initially
but
longer­
term
adaptation
is
e
I
­

not
as
likely
due
to
changes
in
plant
physiology
and
the
questionable
availability
of
an
adequate
water
supply.
Global
warming
may
adversely
affect
ag~
icultural
production
by
reducing
soil
moisture
through
evapotranspiration
and
through
extreme
weather
such
as
droughts,
flooding,
and
tropical
storms.
lo4
The
IPCC
report
explains
that
one
of
the
long
tern1
effects
of
global
warming
will
be
altered
plant
diseases
and
pest
infestations.
lo5
As
a
result
of
these
climate
change
affects
on
agriculture,
an
estimated
40­
306
xnillion
additional
people
worldwide
may
be
a
t
risk
from
hunger.
lo6
2.
Weather­
Related
Ham
and
Rising
Sea
Levels.
­

Extreme
weather
is
predicted
as
a
result
of
changing
climate
condition^.
'^^

More
floods
may
occur
due
to
the'increased
rain
fall
and
more
tropical
cyclones
are
expected
because
of
wanner
sea
surface
temperatures.
'0s
Extreme
weather
will.
not
only
create
physical
harm
and
structural
damage,
but
will
also
create
­

102
See
generally,
International
Rice
Research
Institute
and
American
Association
for
the
Advancement
of
Science,
"Climate
and
Food
Security"
1989.

IO?
Jonathan
A.
Patz,
MD,
MPH,
"Public
Health
Effects
of
Climate
Change:
Synthesis
of
the
Ipcc
Findings"
Statcment
Prepared
for
a
Roundtable
Discussion
of
Senalor
Lieberman,
8
(June
1
1996).

I
O
J
.
'
IPCC,
Ex.
4
at
8.

I
"6
I1)
7
IPCC,
Ex.
4
at
9.

­
Id.

Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
t
o
EPA
­
Octolm
20,1999
26
.
breeding
sites
for
insects
and
rodents
cawing
disease.
'09
The
IPCC
anticipates
that
global
warming
will
also
encourage
human
dislocation
from
geographically
­

4
*
­
vulnerable
areas."
'
Droughts
in
West
Afiica
have
already
forced
mass
migrations."
'

Sea
level
rises
are
occuning
rapidly
in
the
U.
S.
The
EPA
estimates
that
"along
the
Gulf
and
Atlantic
coasts,
a
one
foot
(30
cm)
rise
in
sea
level
is
likely
by
2050
and
could
occur
as
soon
as
2025.
In
the
next
century,
a
two
foot
rise
is
most
likely,
but
a
four
foot
rise
is
possible.""*
Developed
areas
will
probably
attempt
to
protect
their
property
with
bulkheads,
dikes,
and
other
structures,

however,
not
all
property
will
be
pdtected
and
consequently,
many
people
living
in
coastal
areas
will
be
forced
to
relocate."
3
I
3,
H
a
m
to
Water
Quality
and
Quantity.
­

Rising
sea
levels
will
increase
the
salinity
of
surface
and
ground
water.
'14
The
EPA
reports
that­
New
York,
ghiladelphia,
and
much
of
California's
Central
Valley
will
be
susceptible
to
salty
water
during
droughts
if
sea
levels
nse,
'15
Climate
effects
will
also
increase.
flooding
and
water
shortages.
'I6
ro9
­
Id.

­
Id.

­
Id.
110
116
IPCC,
Ex.
4
at
9.

Int'l.
Ctr.
For
Tech.
Assm't.
Legal
Petition
to
EPA
­
October
20,1999
27
."

.
.
.
.
.
.
.
.
­.
.

­
..
4.
Harm
From
Air
Pollution
and
Allergens.

The
industrial
processes
that
produce
greenhouse
gases
also
produce
air
po1lutants.
'l7
In
the
U.
S.,
air
pollution
causes
70,000
deaths
and
one
million
hospitalizations
annually.
'"
The
participants
at
the
Conference
on
Human
Health
and
Global
Climate
Change
predict
that
as
pollution
from
greenhouse
gases
increases,
"the
health
effects
of
air
pollution
on
a
global
scale
could
be
Hotter
temperatures
and
humidity
may
also
lead
to
increased
levels
of
plant
pollen,
which
in
t
u
~m
would
increase
the
cases
of
asthma
and
hay
fever."
'
4
e
­

I
n
sum,
significant
scientific
rGsearch
and
numerous
EPA
findings
conclude
.
that
greenhouse
gases
will'
adversely
affect
human
health
and
welfare
in
the
United
States
by
causing
global
warming.
Based
on
these
determinations,
EPA
must
regulate
the
emissions
of
greenhouse
gases
from
new
motor
vehicles
under
5
202(
a)(
1)
of
the
CAA
in
order
to
mitigate
the
harmful
impacts
of
global
warming
on
both
the
environmental
and
hilman
welfare.
­

II.
IT
IS
TECHNICALLY
FEASIBLE
T
O
REDUCE
GREENHOUSE
GAS
EMISSIONS
FROM
NEW
MOTOR
VEHICLES.

Agency
action
under
5
202
will
allow
the
EPA
to
implement
a
variety
of
regulatory
standards
to
control
greenhouse
gas
emissions.
As
contained
in
5
202,

standards
set
under
5
202
authority
"shall
be
applicable
to
such
vehicles
and
engines
for
the
useful
life
.
.
.
whether
such
vehicle
or,
engines
are
designed
as
complete
systems
or
incorporate
devices
to
prevent
the
control
of
such
pollution."

'
I
7
Conference
on
Human
Health
and
Global
Climate
Change,
Ex.
2
at
13.

I
I
9
­
Id.
at
14.

Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
t
o
EPA
­
October
20,
1999
25
..
.
..

..

..
.
.
­.
..
..
..

.
.
"..
.
.­
/
,

Accordingly,
this
language
allows
the
EPA
latitude
to
utilize
a
number
of
options
­
to
address
new
motor
vehicle
greenhouse
gas
emissions
s
o
long
as
the
options
require
the
incorporation
of
complete
systems
or
devices
that
reduce
such
8
`
­

emissions.
Major
automakers
have
already
introduced
car
and
truck
designs
that
significantly
reduce
vehicle­
related
COz
fonxation,
and
many
of
these
are
already
available
to
consumers
and
institutional
purchasers
at
competitive
prices.
These
vehicles
generally
rely
on
one
of
two
strategies
for
reducing
CO,
emissions:

increasing
fuel
economy
and/
or
eliminating
tailpipe
emissions
altogether.

Standards
assuring
their
rapid
market
adoption
of
these
vehicles
are
necessary
increases
in
new
vehicle
greenhoud
gas
emissions.

A.
Standards
for
Sncreased
Corporate
Average
Fuel
Economy.
lZ1
According
to
the
U.
S.
Department
of
Energy,
"[
Tlhe
fuel
economy
of
avehicle
­

is
directly
related
to
its
emissions
of
carbon
dioxide,
the
most
important
greenhouse
gas."
Furthermore,
$PA
added
that:

[Elven
though
today's
new
vehicles
cause
much
less
air
pollution
than
in
the
past,
their
greenhouse
gas
emissions
are
as
high
as
they
were
15
years
ago.
A
vehicle's
greenhouse
gas
emissions
are
directly
related
to
its
fuel
economy.
Every
gallon
of
gasoline
that
you
use
in
a
vehicle
adds
about
20
pounds
of
carbon
dioxide
to
fie
atmosphere."
'22
The
Corporate
Average
Fuel
Economy
(CAFE)
standard
for
1999
is
27.5
mpg,

though
the
actual
average
fuel
economy
is
somewhat
lower
than
this
because
automakers
are
permitted
to
employ
credits
generated
through
an
averaging,

banking,
and
trading
program.
Also,
light
trucks,
which
make
up
a
growing
It!
US.
DOE,
"Model
Year
1999
Fuel
Economy
Guide,"
DOEEE­
0175,
(JVashington,
DC:
October
1998)
at
2.

Int'l.
Ctr.
for
Tech.
..
issm't.
Legal
Pcti:
ion
tu
EPA
­
Octoher
20,
1999
29
i
segment
of
passenger
vehicle
sales,
are
subject
to
less
stringent
fuel
economy
standards.
Complete
vehicle
systems
and
incorporated
devices
that
yould
~

significantly
reduce
new
vehicle
CO,
emissions
are
currently
in
development
or
on
the
road.
For
example,
the
Union
of
Concerned
Scientists
has
developed
a
blueprint
for
a
sport
utility
vehicle
utilizing
devices
that
would
emit
32
percent
less
CO,
than
comparable
models
now
for
~a
1
e
.f
~~

In
addition,
automakers
have
shown
that
the
technology
is
available
to
support
a
more
stringent
CAF'E
standard.
For
the
1999
model
year,
a
number
of
traditional,
gasoline­
powered
cars
achieve
fuel
economy
ratings
of
at
least
40
rnpg
on
the
highway.
These
include
the
Chevrolet
Metro
(1.0
liter/
3
cylinder
engine,

41
mpg
city/
47
mpg
highway);
Honda
Civic
HX
(1.6/
4,
35/
43),
Mitsubishi
Mirage
(1.5/
4,33/
40),
SatumSL(
1.9/
4,29/
40),
Suzukiswift(
l.
3/
4,39/
40),
andToyota
Tercel
(1.5/
4,
32/
40).
124
3
Even
better
fuel
economy
ratings
are
achievable.
In
199
1,
­the
Congressional
Office
of
Technoloakssessment
established
a
list
of
strategies
for
improving
vehicle
fuel
economy.
Many
remain
viable.
These
automotive
technology
and
design
improvements
include:
weight
reduction,
aerodynamic
drag
reduction,
improved
tires
and
lubricants,
advanced
engine
friction
reduction,
two­

stroke
engines,
and
continuously
variable
transmissions
that
ensure
optimal
'

vehicle
efficiency
at
all
speeds.
'25
12.3
David
Welch,
"Fuel­
Efficient
Sport­
Utility
Is
Envisioned,"
Detroit
Neb\.
s,
July
16,
1999,
at
~1
5
.

Int'l.
Ctr.
for
Tech.
Assrn't.
Legal
Petition
to
EPA
­
October
20,1399
30
B.
Increased
Adoption
of
Hybrid
and
Non­
Fossil
Fuel
The
setting
of
standards
under
3
202
will
create
4
8
­
,/

Vehicles.

the
rapid
market
­

introduction
of
hybrid­
electric
and
zero
emission
vehicles.
By
encouraging
the
development
of
this
technology,
the
agency
can
effectively
reduce
greenhouse
gas
emissions
from
new
vehicles.

Ilybricl
technologies
utilize
entirely
new
systems
combining
a
gasoline­

powered
engine
and
a
batteqr­
powered
electric
motor.
The
energy
used
to
charge
the
battely
is
typically
generated
by
the
gasoline
engine.
Toyota
has
sold
neal­
ly
30,000
of
its
hybrid­
electric
Prius
i
n
Japan
since
December
1997,
and
plans
to
release
the
model
in
the
United
Stdtes
in
2000.
In
a
recent
4,200­
mile
cross­

continent
trip,
the
Prius
demonstrated
a
fuel
economy
of
over
60
miles
per
gallon.
126
Other
automakers
are
also
working
on
hybrid
models.
Honda
plans
to
begin
selling
the
Insight
hybrid­
electric
vehicle
in
the
United
States
in
December
of
this
year.
The
company
claims
that
the
car
will
get
84
miles
per
gallon
of
gasoline.
General
Motors,
Ford,
&l
DainllerChrysler
are
also
developing
hybrid­

electric
vehicles,
which
they
may
release
for
public
sale
as
early
as
200
1.
127
The
setting
of
new
5
202­
based
CAFE,
standards
by
the
EPA
would
greatly
enhance
market
penetration
of
these
vehicles.

In
addition,
other
new
complete
vehicle
systems
exist
for
reducing
n
e
t
,

vehicle­
greenhouse
gas
emissions.
According
to
the
Califomia
Air
Resources
Board,
there
are
at
least
16
zero­
emission
production
vehicles
now
available
to
consumers
in
at
least
some
states.
These
are
electric
vehicles
(EVs)
and
include
models
of
the
Dodge
Caravan,
Ford
Ranger
pickup,
General
Motors
S­
10
pickup,

and
Plymouth
Voyager.
Recent
technological
advancements
have
dramatically
I26
"Environmental
Adventurers
First
to
Cross
the
U.
S.
i
n
a
Hybrid­
Electric
Car."
PR
Newswire,
J
~l
y
9:
1999.

127
"Honda
Unveils
Fuel
Efficient
Car,"
Associated
Press,
July
6,
1999.

Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
t
o
EPA
­
October
10,
1999
31
,/

_­
A
increased
the
range
of
EVs.
The
General
Motors
EV­
1
with
a
nickel
metal
hydride
battery
can
travel
up
to
152
miles
on
a
single
charge,
while
the
Toyota
RAV
4
and
Nissan
Alta
EVs
also
boast
ranges
exceeding
100
miles
per
charge.
lZ8
EVs
have
no
tailpipe
emissions
and
carry
the
potential
to
reduce
all
automobile­
related
CO,

emissions
to
near
zero.
The
agency
itself
has
found
that,
``[
Ilf
power
plants
produce
electricity
using
clean
energy
sources
such
as
solar
or
hydro
power,

emissions
are
negligible."
129
Additionally,
fuel
cell
vehicles
may
soon
offer
another
zero­
emissions
option.

A
fuel
cell
combines
hydrogen
and
o`
xygen
in
a
chemical
reaction
that
produces
electricity.
The
exhaust
of
a
fuel
cell
running
on
pure
hydrogen
consists
of
water
and
hot
air.
Ford
has
developed
a
research
vehicle
kno.~
vn
as
the
P2000
.HFC,

which
runs
on
a
fuel
cell
and
emits
no
CO,
precursors.
The
company
plans
to
begin
testing
about
45
fuel
cell
cars
and
buses
in
California
over
the
next
several
years.
130
Other
companies
developing
automotive
fuel
cell
technologies
inch&

Ballard
Power
Systems,
DaimlerCh'iysler,
and
Toyota.
$r
Unfortunately,
the
Agency's
proposed
Tier
11.
standard
has
inadequately
addressed
the
effects
of
greenhouse
gas
emissions,
including
CO,
emissions,
from
new
vehicles.
13'
Given
the
agency's
intention
of
using
the
Tier
I1
process
to
develop
a
regulatory
framework
that
addresses
future
automobile
pollution,
petitioners
believe
that
the
authority
provided
under
5
202
requires
the
agency
to
incorporate
12s
California
Air
Resources
Board,
"Buyer's
Guide
to
Cleaner
Cars,"
updated
March
8,
1999,
<http://\
v\~
W.
arb.
ca._
gov/
mspro~/
ccb~
ccb~.
htm>.

`29
U.
S.
Environmental
Protection
Agency,
"Electric
Vehicles,"
Fact
Sheet
OAlS­
10,
EPA
400­
f­
92­
0
12,
August
1994.

1.31
See
gemrdiy,
The
International
Center
for
Technology
Assessment's
Comments
on
the
U.
S.
Environlnental
Protection
Agency's
Tier
2
Proposal
(Public
Docket
No.
A­
97­
10),
August
2,
1999.

Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
to
EPA
­
October
20,
1999
32
/
,

I.
A.
/

standards
into
its
Tier
2
proposal
that
would
combat
global
warming
by
limiting
the
amount
of
C02
pollution
created
by
light
duty
vehicles.
For
example,

establishing
a
declining
NO,
fleet
average
in
the
proposed
Tier
I1
regulation
would,

in
part,
achieve
such
a
goal
by
requiring
manufacturers
to
increase
the
number
of
vehicles
certified
to
the
zero
emission
vehicles
standards
of
proposed
Bin
1.
b
`

Given
the
scope
of
authority
granted
to
the
Administrator
under
5202
and
the
existence
of
the
requisite
technologies,
the
Administrator
can
set
a
number
of
new
standards
for
devices
incorporated
into
new
vehicles
that
\vi11
reduce
the
emissions
of
greenhouse
gas
air
pollutant^.
'^
'
3
Having
already
made
formal
findings
that
the
emission
of
air
pollutants
C02,

CH,,
N20,
and
HFCs
from
mobilepources
poses
actual
or
potential
harmful
effects
of
the
public
health
and
welfare,
'33
the
Administrator
must
exercise
her
authority
to
regulate
the
emissions
of
CO,;
CH,,
N,
O,
and
HFCs,
from
new
motor
vehicles
under
3
202(
a)(
l).
Section
202(
a)
states
that
the
Administrator
"shall
by
regulation
prescribe
.
.
.
standards
applicable
to
any
air
pollutant
from
any
.
.
.

class
or
classes
of
new
motor
vehicles"
(emphasis
added).
Prior
court
decisions
have
found
that
the
use
of
"shall"
in
3
202
creates
a
mandatory.
duty
to
promulgate
standard^.
'^^
Accordingly,
the
Administrator
must
act
to
implement
,*

132
For
example,
such
standards
could
even
include
such
things
as
tire
efficiency
standards.

133
See
supra.
Argument
I
(a)
Pr.
(b).

""
NRDC
v.
Reillv.
983
F.
2d
259,
266­
67
(D.
C.
Cir.
1993j*(
findins
that
use
of
"shall"
i
n
g
202(
a)(
6)
mandated
promulgation
of
standards
requiring
new
light
duty
vehicles
be
equipped
with
oilboard
refueling
vapor
recovery
system):
See
also,
Hetvitt
v.
Helms,
459
U
S
.
460,
471,
74
L.
Ed.
2d
675,
103
S.
Ct.
564
(19S3)(
``
shall'`
is
"language
of
an
unmistakably
mandatory
character"):
Her
Maiectv
the
Queen
v.
EPA.
912
F.
2d
1525,
1533
(D.
C.

Jnt'l.
Ctr.
for
Tech.
Assnl't.
Legs1
Petition
Lo
EPA
­
Octoher
10,
1939
33
/
/
"
/

the
standards
requested
by
this
petition.
­
Further,
even
should
the
agency
believe
that
there
are
scientific
uncertainties
regarding
the
actual
impacts
from
global
warming,
the
precautionary
purpose
of
the
CAA
supports
actions
regulating
of
these
gases.
In
Lead
Industries
Assoc..
Inc.
v.
EPA,
the
court
explained
that:
e
a
­

requiring
EPA
to
wait
until
it
can
conclusively
demonstrate
that
a
*

particular
effect
is
adverse
to
health
before
i
t
acts
is
inconsistent
with
both
the
Act's
precautionaly
and
preventive
orientation
and
the
nature
of
the
Administrator's
statutory
responsibilities
.
.
.
Congress
directed
the
Administrator
to
err
on
the
side
of
caution
in
making
the
necessaly
decisions.
135
2
The
Administrator's
authority
to
use
precaution
when
regulating
air
pollutants
is
also
elaborated
upon
in
Ethyl
Corp.
v.
EPA.
'36
In
this
case,
the
court
stated
that
"[
tlhe
Administrator
may
apply
[her]
expertise
to
draw
conclusions
from
suspected,

but
not
completely
substantiated
relationships
between
facts,
from
trends
among
facts,
from
theoretical
projects
from
imperfect
data,
from
probative
preliminary
data
not
yet
certifiable
as
fact,
ahd
the
like."
'37
Thus,
the
Administrator's
clear
mandate
to
regulate
greenhouse
gases
under
5
202
cannot
be
excused
by
a
post
hoc
rationalization
of
scientific
uncertainty.
­

e
;

Based
upon,
inter
alia,
the
evidence
presented
herein,
the
petitioners
request
the
Administrator
to
immediately
begin
regulating
the
emissions
of
the
greenhouse
gases
­
CO,,
CH,,
N,
O,
and
HFCs
­
from
new
motor
vehicles
as
required
by
5
202(
a)(
l).
Should
the
Admifiistrator
not
undertake
this
mandatory
duty,
her
inaction
can
be
subject
to
judicial
review.

Cir.
1990)
("
shall"
signals
mandatory
action).

1.
v
541
F.
2d
1
(D.
C.
Cir.)
(en
banc),
cert.
cletried,
426
U.
S.
941
(1976).

I17
Id.
at
2s.
­

Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
t
o
EPA
­
October
20,1999
34
..
.
/
i
­

CONCLUSION
/

3
`

WHEREFO&,
petitioners
request
that
the
Administrator:
'38
(1).
Regulate
the
emissions
of
carbon
dioxide
(COJ
from
new
motor
vehicles
and
new
motor
vehicle
engines
under
5
202(
a)(
l)
of
the
Clean
Air
Act:

(2).
Regulate
the
emissions
of
methane
(CH,)
from
new
motor
vehicles
and
new
motor
vehicle
engines
under
5
202(
a)(
l)
of
the
Clean
Air
Act;

(3).
Regulate
the
emissions
of
nitrous
oxide
(N,
O)
from
new
motor
vehicles
and
new
motor
vehicle
eygines
under
5
202(
a)(
l)
of
the
Clean
Air
Act;

(4).
Regulate,
the
emissions
of
hydrofluorocarbons
(HFCs)
from
new
motor
vehicles
and
new
motor
vehicle
engines
under
5
20Z(
a)(
1)
ofthe
Clean
Air
Act;

­
AS
required
by
law,
the
EPA
is
required
to
give
this
petition
prompt
consideration.
Additionally,
undei­
..
the
Administrative
Procedure
Act
"agency
action"
is
defined
to
include
"the
whole
or
part
of
an
agency
rule,
order,
license,

sanction,
relief,
or
the
equivalent
denial
thereof,
or
failure
to
act."
Therefore,

petitioners
are
requesting
a
substantive
response
to
this
petition
within
one
hundred
eighty
(180)
calender
days.
I3'
In
the
absence
of
an
affirmative
response,

petitioners
will
be
compelled
to
consider
litigation
in
order
to
achieve
the
agency
actions
requested.
I4'
..

~~~~~~~

13s
Rulernaking
undertaken
pttrsuant
to
this
petition
must
cornply
with
the
requirements
contained
in
307(
d),
42
U.
S.
C.
7607(
d).

I39
Petitioners
note
that
a
response
period
of
1
SO
days
is
reasonable
under
the
APA.
See,
42
U.
S.
C.
9
76O:!(
n)
xquil­
ing
notice
c)
T
!
F9
c!?;;:
yyi?:
p
x::::::::::
of
2::
::::
i?:?,
F>:
:!
n:.
e:,
s::?`
s!~..
5!~
d:!:.;;.
SI.:
n!
jq
2
I
C.
F.
Z.
$lO.
3O(
e)(
2)
(1998)
(FDA's
implementation
of
the
Administrative
Procedure
Act's
petitioning
provisions).

Petitioners
also
assert
that
through
the
filing
of
this
petition
they
have
complied
with
citizen
suit
notice
requirements
established
i
n
$
304:
42
U.
S.
C.
5
76011..

Int'l.
Ctr.
for
Tech.
Assm`
t.
Legal
Pclition
to
EPA
­
October
20,
1999
35
..

.
..
..
..
.­
.
I
/

I.
,/
J
­
,

I
*
Respectfully,
submitted,

Legal
Directbr
International
Center
for
Technology
Assessment
310
D
Street,
N.
E.
Washington
DC
20002
3
Of
Counsel:
Andrew
C.
Kimbrell
&
Tracie
Letterman
International
Center
for
Technology
Assessment
3
10
D
Street,
N.
E.
Washington,
DC
20002
­

,ATTORNEYS
FOR
PETITIONERS
,.

CC:
Via
First
Class
Mail
..

Vice
President
Albert
Gore
Office
of
the
Vice
President
1600
Pennsylvania
Ave.,
NW
Washington,
DC
20505
Mr.
Robert
Perciasepe
Assistant
Administrator
Office­
of
Air
and
Radiation
Mail
Code
6101A
U.
S.
EPA
Headquarters
401
M
Street,
SW
Washington.
D'C
20460
Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
to
EPX
­
October
10,
1999
36
\
.­.
I
Ms.
Margo
Oge
Office
of
Mobile
Sources
e
*
Mail
Code
6401A
U.
S.
EPA
Headquarters
401
M
Street,
SW
Washington,
DC
20460
Int'l.
Ctr.
for
Tech.
Assm't.
Legal
Petition
to
EPA
­
October
20,1999
...
..
.
­
..
..
..

..
...
.
..
..
.
­,
,I
"

3
37
­.
.~

..
..
.
.
..
..
..
.
..
..
.....
....

..

...
...

.
,.
,
...
1
.

­.
I
.
CLIMATE
CHANGE
1995
­
The
Science
of
Climate
Change,"
".

Foreword
The
Intergovernmental
Panel
on
Climate
Change
(IPCCI
was
jointly
established.
by
the
World
bleteorological
Organization
and
the
United
Nations
,
Environment
Programme
in
1988,
in
order
to:
(i)
assess
available
scientific
information
on
climate
change,
(ii)
assess
the
environmental
and
socio­
economic
impacts
of
climate
change.
and
(iii)
formulate
response
strategies.
The
IPCC
First
Assessment
Report
was
completed
in
August
1990
and
served
as
the
basis
for
negotiating
the
UN
Framework
Convention
on
Climate
Change.
The
IPCC
also
completed
its
1992
Supplement
and
"Climate
Change
1994:
Radiative
Forcing
of
Climate
Change
and
.An
Evaluation
of
thc
IPCC
IS32
Emission
Scenarios"
to
a
d
s
t
the
convention
process
further.
In
1992,
the
Panel
reorganised
its
Working
Groups
11
and
I
l
l
and
committed
itself
to
complcte
a
Second
.Assessment
in
1995,
not
only
updating
the
information
on
the
same
range
of
topics
as
in
the
First
Assessment.
but
also
including
the
new
subject
area
of
technical
issues
related
to
the
economic
aspects
of
climate
change.
We
applaud
the
IPCC
for
producing
its
Second
Assessment
Report
(SARI
as
scheduled.
iVe
are
convinced
that
the
SAR,
like
the
earlier
IPCC
Reports.
wili
become
a
standard
work
of
reference.
widely
used
by
policymakers,
scientists
and
other
csperts.
This
documcnt.
which
tontains
the
Summary
for
Policymakers
and
Technical
Summary
of
the
full
il'orking
Group
I
report,
represents
part
of
the
Working
Group
I
contribution
to
the
SAR.
It
discusses
the
physical
climate
system,
the
factors
that
drive
climate
change,
analyses
of
past
climate,
detection
and
attribution
of
a
human
influence
on
recent
climate
and
projections
of
,future
climate
change.

I
As
usual
in
the
IPCC,,
success
in
producing
this
document
and
the
full
report
on
which
it
is
based
has
depended
upon
the
enthusiasm
and
co­
operation
of
numerous
busy
scientists
and
other
experts
world­
uide.
!\
'e
are
exceedingly
pleased
to
note
here
the
very
special
efforts
made
by
the
IPCC
in
ensuring
the
participation
of
scientists
and
other
reviewing.
and
revising
of
its
reports.
The
scientists
and
experts
from
the
developed,
deveioping
and
transitional
economy
countries
have
given
of
their
time
very
generously,
and
governments
have
supporred
them,
in
the
enormous
intellectual
and
­

P
V
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.­
.
physical
effort
required,
often
going
substanriall!.
beyond
reasonable
demands
of
duty.
\Vichour
such
conscientious
and
professional
involvement.
tht.
IPCC
would
be
greatly
impoverished.
M'e
express
to
all
t
h
e
s
e
s
c
i
e
n
t
i
s
t
s
a
n
d
e
s
p
e
r
t
s
,
a
n
d
the
governments
who
supported
them,
our
sincere
appreciation
for
their
commitment.
!Ye
take
this
opportunity
to
express
our
gratitude
to
the
following
individuals
for
nurturing
another
IPCC
report
through
to
a
successful
completioil:
Prof.
Bolin.
the
Chairman
of
the
IPCC,
for
his
able
leadership
and
skilful
guidance
of
the
IPCC:
the
Co­
chairmen
of
IVorking
Group
I
.
Sir
John
Houghron
(United
Kingdom))
and
Dr.
L.
G.
hleira
Filho
(Brazil):
the
Vice­
Chairmen
of
the
IVorking
Group,
Prof.
Ding
k'ihui
(China),
Llr.
A.
B.
Diop
(Senegal)
and
Prof.
D.
Ehhalt
(Germany);
Dr.
B.
A.
Callander,
the
Head
of
.
the
Technical
Support
Unit
of
the
LVorking
Group
and
his
staff,
XIS.
K.
Maskell,
Mrs.
J.
A.
Lakeman
and
Mrs.
F.
hlills,
with
additional
assistance
from
Dr.
N.
Harris
(European
Ozone
Research
Co­
ordinating
Unit,
Cambridge),
Dr.
A.
Kattenberg
(Royal
Netherlands
bleteorological
Institute);
and
Dr.
N.
Sundararaman.
the
Secretarrof
the
IPCC
and
his
staff
including
Mr.
S.
Tewungwa.
Slrs.
R.
Bourgeois,
Ms.
C.
Ettori
and
Ms.
C.
Tanikie.

G.
O.
P.
Obasi
Secretary­
General
World
Meteorological
Organization
Ms.
E.
Dowdesnell
Executive
Director
United
Nations
Environment
Programme
Preface
This
iocument
comprises
both
the
Summary
for
Policymakers
and­
the
Technical
Summary
of
the
LVorking
Group
I
(WGI)
report.
It
represents.
in
conjunction
with
the
11
chapters
of
the
underlying
CVGI
report
from
which
this
material
was
drawn.
the
most
comprehensive
assessment
of
the
science
of
climate
change
since
PVGI
of
the
IPCC
produced
its
first
report
Climate
Change:
The
IPCC
Scientific
Assessment
in
1990.
I
t
enlarges
and
Updates
information
contained
in
that
assessment
and
also
in
the
interim
reports
produced
by
CVGI
in
1992
and
199­
1.
The
first
IPCC
Assessment
Report
of
1990
concluded
that
continued
accumulation
of
anthropogenic
greenhouse
gases
in
the
atmosphere
would
lead
to
climate
change
whose
rate
a
n
Q
magnitude
were
likely
to
have
important
impacts
on
n
a
t
u
r
a
l
a
n
d
h
u
m
a
n
s
y
s
t
e
m
s
.
T
h
e
IPCC
Supplementary
Report
of
1992,
timed
to
coincide
with
the
final
negotiations
of
the'
United
Nations
Framework
Convention
on
Climate
Change
in
Rio
de
Janeiro
(June
1992).
added
new
quantitative
information
on
the
climatic
effects
of
aerosols
but
confirmed
the
essential
conclusions
of
the
1990
assessment
concerning
our
understanding
of
clinwtc
and
the
factors
affecting
it.
The
1994
CVGI
report
Kadiative
Forcing
of
Climate
`Change
ettamin'cd
in
depth
the
mechanisms
that
govern
the
relative
importance
of
human
and
natural
factors
in
giving
rise
to
radiative
forcing,
the
"driver"
of
climate
change.
The
1994
report
incorporated
further
advances
in
the
quantification
of
the
climatic
effects,
of
aerosols,
but
it
also
found
no
reasons
to
alter
in
any
fundamental
way
those
conclusions
of
the
1990
report
which
it
addressed.
.
­
!\`
e
believe
the
essential
message
of
this
report
.
continues
to
be
that
the
basic
understanding
of
climate
change
and
the
human
role
therein.
as
expressed
in
the
1990
report,
still
holds:
carbon
dioside
remains
the
most
important
contributor
to
anthropogenic
forcing
of
climate
change;
projections
of
future
global
mean
temperature
change
and
sea
level
rise
confirm
the
potential
for
human
activities
t
o
a
l
t
e
r
t
h
e
E
a
r
t
h
'
s
c
l
i
m
a
t
e
to
an
estent
unprecedented
in
human
history;
and
the
long
time­

greenhouse
gases
in
the
atmosphere
and
the
response
of
t
h
e
c
i
i
m
a
t
e
s
y
s
t
e
m
to
thcsc
accumulations,
means
that
many
important
aspects
of
climate
change
are
effectively
irreversible.
Further.
that
observations
suggest
"a
discernible
I
C"..
l
_.__
,<
~n
~;e
r
­n
i
n
g
h
[i
1
thv
accurnulz;
ion
OP
0
­

"

I
.

.
~.
..
..
..
..

.
.
CLIk!
ATE
Ci+
ANGk
;Yba
­
:ne
>C
~~C
I
L
.O
us
*D
<B
~~P
:­
v
8
:y
,.t
l
­

,'
­_

human
influence
on
global
climate".
one
of
the
key
findings
of
this
report
adds
an
important
netv
dimension
to
the
discussion
of
the
climate
change
issue.
An
important
political
development
since
1990
has
been
the
entry
into
force
of
the
VX
Framework
Convention
on
Clinlate
Change
(FCCC).
IPCC.
is
recognised
as
a
prime
source
of
scientific
and
technical
information
to
the
FCCC,
and
the
underlying
aim
of
this
report
is
to
proljde
objective
information
on
which
to
base
global
climate
change
policies
that
will
meet
the
ultimate
aim
of
the
FCCC
­
espressed
in
Article
2
of
the
Convention
­
of
stabilisatiop
of
greenhouse
gases
at
some
level
that
has
yet
to
be
quantified
but
which
is
defined
as
one
that
will
"prevent
dangerous
anthropogenic
interference
with
the
climate
system".
Because
the
definition
of
"dangerous"
will
depend
on
value
juclgements
as
well
as
upon
observable
physical
changes
in
the
climate
system,
such
policies
will
not
rest
on
purely
scientific
grounds,
and
the
companion
IPCC
.reports
by
CVGII
on
Impacts,
Adaptations
and
Mitigation
of
Climate
Change.
and
by
\t`
GIII
on
Economic
and
Social
Dimensions
of
­
i
Climate
Change
provicle
some
of
the
background
information
on
which
the
wider
debate
will
be
based.
Together
the
three
WG
reporis
establish
a
basis
for
an
IPCC
synthesis
of
information
relevant
to
interpreting
Article
2
of
the
FCCC.
An
important
contribution
of
LVCI
to
this
synthesis
has
been
an
analysis
of
the
emission
pathtvays
for.
carbon
dioside
that
would
lead
to
a
range
of
hypothetical
stabilisation
levels.
The
Summary
for
Policymakers
and
Technical
Summary
were
compiled
between
January
and
November
1995
by
78
lead
authors
from
20
countries
with
assistance
from
a
few
additional
esperts
with
experience
of
the
science­
policy
­

interfacp.
Formal
review
of
the
summaries
by
`

governments,
non­
governmental
organisations
(KGOs)
and
individual
experts
took
place
during
hlay
to
July.
Over
400
contributing
authors
from
26
countries
submitted
draft
test
and
information
to
the
lead
authors
and
over
500
reviewers
from
40.
countries
submitted
valuable
suggestions
for
improvement
during
the
review
process.
The
hr:
ndrrc!
s
of
comments
wceiverl
were
carefully
analysed
and
assimilated
in
a
revised
docunlent
tha;
;.;
as
distributed
to
countries
and
%Os
sis
weeks
in
adsance
of
the
fifth
session
of
lVGI
in
blaclrid.
27­
29
.November
1993.
I
t
was
at
this
.session.
ivhere
participants
inclucled
177
delegates
..

­.

..
.
.

..
.

.I
3
..
,/
,
r­

from
96
countries,
representatives
from
14
NGOs
and
28
lead
authors,
that
the­
Summary
for
Policymakers
was
approved
in
detail
and
the
underlying
11
chapters
of
the
full
WGI
report
accepted.
The
Technical
Summary
to
the
WGI
report,
and
the
report
itself,
were
accepted
at
IPCC­
XI
in
Rome,
11­
15
December
1995.
We
wish
first
of
all
to
express
our
sincere
appreciation
to
the
lead
authors
whose
expertise,
diligence
and
patience
have
underpinned
the
successful
completion
of
this
effort,
and
to
the
many
,

contributors
and
revietvers
for
their
valuable
and
p
a
i
n
s
t
a
k
i
n
g
w
o
r
k
.
l
y
e
a
r
e
g
r
a
t
e
f
u
l
t
o
t
h
e
governments
of
Sneden,
UK
and
USA
which
hosted
drafting
sessions
in
their
countries,
and
to
the
government
of
Spain
\vh!
ch
hosted
the
final
session
of
Working
Group
I
in
Sladrihtjat
which
the
documents
were
accepted
and
approved.
The
IPCC
Trust
Fund,
contributed
to
by
many
countries,
supported
the
participation
of
many
developing
country
scientists
in
the
completion
of
this
report.
The
WGI
Technical
Support
Unit
was
funded
by
the
UK
government
with
assistance
from
the
Netherlands,
and
we
echo
the
appreciation
espresscd
in
the
Foreword
to
the
members
'of
the
Technical
Supporr
Unit.

.
'
Bert
Bolin
­.

IPCC
chairman
John
Houghton
Co­
chair
(UK)
IPCC
lVG1
.

L.
Gylvan
Meira
Filho
Co­
chair
(Brazil)
IPCC
\VGI
4
..
.
­
­­
..
..
.
..
.
.
­.
."
.
.
­.

.
..
.
.
..
.

..
.
.
..
.
,.
..
Contekrts
.
,.
..­.
/

Summary
for
Policymakers
Technical
Summary
of
t
h
e
Full
Working
Group
I
Report
I
A
Introduction
B
Greenhouse
Gases,
Aerosols
and
their
Radiative
Forcing
B.
l
Carbon
dioside
(CO,)
B.
2
Methane
(CH,)
B.
3
Nitrous
oxide
(N20)
B.
4
Halocarbons
and
other
halogenated
compounds
B.
5
Ozone
(0,)
B.
5.1
Tropospheric
Ozone
B.
5.2
Stratospheric
Ozone
B.
6
Tropospheric
and
stratospheric
aerosols
B.
7
Summary
of
radiative
forcing
B.
S
Global
\\`
arming
Potential
(G\
VP)
B.
9
Emissions
and
concentrations
of
greenhouse
gases
and
aerosols
in
the
future
B.
9.1
The
IS92
emission
scenarios
B.
9.2
Stabilisation
of
greenhouse
gas
and
aerosol
concentrations
9
C
Observed
Trends
and
Patterns
in
Climate
and
Sea
Level
C.
l
Has
the
climate
warmed?
C.
2
Is
the
20th
century
warming
unusual?
C.
3
Has
the
climate
become
wetter?
C.
4
Has
sea
level
risen?
C.
5
Has
the
climate
become
more
variable
and/
or
extreme?
D
Modelling
Climate
and
Climate
Change
D.
l
The
basis
for
confidence
in
climarb
models
D.
2
Climate
model
feedbacks
and
uncertainties
E
Detection
of
Climate
Change
and
:Attribution
of
Causes
E.
l
Better
simulations
for
defining
;.
human­
induced
climate
change
"signal"
E.
2
Better
simulations
for
estimating
natural
internal
climate
variability
E.
3
Studies
of
global
mean
change
'
.
E.
4
Studies
of
patterns
of
change
E.
5
Qualitative
consistency
E.
6
Overall
assessment
of
the
detection
and
attribution
issues
F
The
Prospects
for
Future
Climate
Change
E
l
Forcing
scenarios
,
'

E2
Projections
of
climate
change
F.
2.1
Global
mean
temperature
response
to
IS92
emission
scenarios
F.
2.2
Global
mean
sea
level
response
to
IS92
emission
.scenarios
F.
2.3
Temperature,
and
sea
level
projections
compared
with
IPCC
(1990)

F.
3.1
Continental
scale
patterns
F.
3.2
Regional
scale
patterns
F.
3.3
Changes
in
variability
and
cstrcmcs
E3
Spatial
patterns
of
projected
climate
change
E4
Effects
of
stabilising
greenhouse
gas
concentrations
E5
The
possibility
of
surprises
G
Advancing
our
Understanding
Glossary
References
7
15
16
18
15
21
"
3
3
"
73
23
23
23
24
24
25
25
25
29
31
31
32
33
35
35
37
37
39
41
41
41
41
42
43
43
44
44
44
4
1
45
4G
47
47
49
43
50
51
5
2
53
JJ
"

..
I
.
.
..
..
.
..
.
..
.,
­.
.
.
..
.
­­
..
3
G
..
..
.
.
..
.
­.
..
..
.:
..
Summary
for
POiiCymakets
­

SUMMARY.
FOR
POLICYMAKERS
This
summary,
approved
in
detail
at
the
fifth,
session
ofIPCC
Working
Group
I,
(Madrid,
27­
29
November
1995),
represents
the
formally
agreed
statement
of
the
IPCC
concerning
current
understanding
of
the
science
of
climate
change.
..

Summary
for
Policymakers
Considerable
progress
has
been
macle
in
the
understanding
of
climate
change'
science
since
1990
and
new
data
and
analyses
have
become
available.

Greenhouse
gas
concentrations
have
continued
to
increase
'

Increases
in
greenhouse
gas
concentrations
since
pre­
industrial
times
(i.
e.,
since
about
1750)
have
led
to
a
positive
radiatiae
forcing2
of
climate,
tending
to
warm
the
surface
and
to
produce
other
changes
of
climate.

0
The
atmospheric
concentrations
of
greenhouse
gases,
inter
diu
carbon
dioside
KO2).
methane
(CHJ
and
nitrous
oxide
(PI201
have
grown
significantiy:
by
about
30%,
145%
and
15%
respectively
(values
for
1992).
These
trends
can
be
attributed
largely
to
human
activities,
mostly
fossil
fuel
use,
'land­
use
change
and
agriculture.
3
0
The
growth
rates
of
CO?,
CH4
and
N
2
0
concentrations
were
low
during
the
early
1990s.
\Vhile
this
apparently
natural
variation
is
not
yet
fully
esplained,
recent
data
indicate
that
the
growth
rates
are
currently
comparable
to
those
averaged
over
the
1980s.

0
The
direct
radiative
forcing
of
the
long­
lived
greenhouse
gases
(2.45
Wm­
2)
is
due
primarily
to
increases
in
rhe
concentrations
of
CO2
(1.56
Wm­
2),
CH4
(0.47
Wm­
2)
and
N20
(0.14
IVm­
2)
(values
f
o
r
1
9
9
2
).
­

0
Many
greenhouse
gases,
remain
in
the
atmosphere
for
a
long
time
(for
CO,
and
N20.
many
'
,
decades
to
centuries),
hence
they
affect
radiative
forcing
on
long
time­
scales.,

0
The
direct
radiative
forcing
due
to
the
CFCs
and
H.
CFCs
combined
is
0.25
Wm­
2.
Holyever,
their
net
radiative
forcing
is
reduced
by
about
0.1
tVm'z
because
they
have
caused
stratospheric
ozone
depletion
which
gives
rise
to
a
negative
radiative
forcing.

0
Growth
in
the
concentration
of
CFCs,
but
not
HCFCs,
has
slowed
to
about
zero.
The
concentrations
of
both
CFCs
and
HCFCs,
and
their
consequent
ozone
depletion.
are
expected
to
decrease
substantially
by
2050
through
implementation
of
the
Montreal
.Protocol
and
its
Adjustments
and
.Amendments.

0
At
present
some
long­
lived
greenhouse
gases
(particularly
HFCs
(a
CFC
substitute),
PFCs'and
SF61
contribute
little
to­
radiative
forcing
but
their
projected
growth
could
contribute
several
per
cent
to
radiative
forcing
during
the
21st
century.

0
If
carbon
dioxide
emissions
were
maintained
at
near
current
(1994)
levels,
they
would
lead
to
a
nearly
constant
rate
of
increase
in
atmospheric
concentrations
for
at
least
two
centuries.
reaching
about
500
ppmv
(approaching
twice
the
pre­
industrial
concentration
of
280
ppmv)
by
the
end
of
the
21st
century.

Climate
change
in
lPCc
LVorking
GroG?
f
usage
refers
t
o
any
change
in
climate
over
time
whether
due
to
natural
variability
or
as
a
result
of
human
activity.
This
divers
frnm
the
usage
in
the
Framework
Convention
on
Climate
Change
where
climate
change
refers
t
o
a
change
of
climate
which
is
attributed
directly
or
indirectly
t
o
human
activity
that
alters
the
compositjon
o
f
the
global
atmosphere
and
which
is
in
addition
t
o
natural
climate
variability
observed
over
comparable
time
periods.
O
A
range
of
carbon
cycle
models
indicates
that
stabilisation
of
atmospheric
COz
concentrations
at
450,
650
or
1000
ppmv
could
be
achieved
only
if
global
anthropogenic
CO2
emissions
drop
to
1990
levels
by,
respectively.
approximately
40,
140
or
240
years
from
now,
and
drop
substantially­
below
1990
levels
subsequently.
a
0
Any
eventual
stabilised
concentration
is
governed
more
by
the
accumulated
anthropogenic
CO,
emissions
from
now
until
the
time
of
stabilisation,
than
by
the
ivax
those
emissions
change
over
the
period.
This
means
that,
for
a
given
stabilised
concentration
value,
higher
ernissions.
in
early
decades
require
lower
emissions
later
on.
Among
the
ranie
of
stabilisation
cases
studied,
for
stabilisation
at
450.
650
or
1000
ppmv
accumulated
anthropogenic
emissions
over
the
period
1991
to
2100
are
630
GtCl,
1030
GtC,
and
1410
GtC
respectively
(~t
approsimately
15%
in
each
case).
For
comparison
the
corresponding
accumulated
emissions
for
IPCC
IS92
emission
scenarios
range
from
770
to
2190
GtC.

0
Stabilisation
of
CH,
and
N20
concentrations
at
today's
levels
would
involve
reductions
in
3
0
There
is
evidence
that
tropospheric
ozone
concentrations
in
the
Northern
Hemisphere
have
'
increased
since
pre­
industrial
times
because
of
human
activity
and
that
this
has
resulted
in
a
positive
radiative
forcing.
This
forcing
is
not
yet'well
characterised.
but
it
is
estimated
to
be
about
0.4
Wm­
2
(15%
of
that
from
the
long­
lived
greenhouse
gases).
However
the
observations
of
the
most
recent
decade
shoiy
that
the
upward
trend
has
slowed
significantly
or
stopped.
anthropogenic
emissions
of
S%
and
more
than
50%
respectively.

Anthropogenic
aerosols
tend
to
produce
negative
radiative
forcings
0
Tropospheric
aerosols
(microscopic
airborne
particles)
resulting
from
combustion
of
fossil
fuels,
b,
iomass
burning
andother
sourcds
have
led
to
a
negative
direct
forcing
of
about
0.5
W
m
­2
,
as
a`
global
average,
and
possi$~
y
also
to
a
negative,
indirect
forcing
of
a
similar
magnitude.
While
the
negative
forcing
is
focused
in
particular
regions
and
subcontinental
areas,
it
can
have
continental
to
hemispheric
scale
effects
on
climate
patterns.

0
Locally,
the
aerosol
forcing
can
be
large
enough
to
more
than
offset
the
positive
forcing
due
to
greenhouse
gases.

0
In
contrast
to
the
!origylived
greenhouse
gases.
anthropogenic
aerosols
are
very
short­
lived
in
the
atmosphere,
hence
their
radiative
Forcing
adjusts
rapidly
to
increases
or
decreases
in
emissions.

Climate
has
changed
over
the
past
century
At
any
one
location
year­
to­
year
variations
in
weather
can
be
large,
but
analyses
of
meteorological
and
other
data
over
large
areas
and
over
periods
of
decades
or
more
have
provided
evidence
for
some
important
systematic
changes.

0
Global
mean
surface
air
temperature
has
increased
by
between
about
0.3
and
0.6"
C
since
the
'
late
19th
century;
the
additional
data
available
since
1990
and
the
re­
analyses
since
then
have
.­

R
o
t
significantly
changcd
this
range
of
cs:
in:
atcd
increase.

0
Recent
years
have
been
among
the
warmest
since
18.60,
i.
e.,
in
the
period
of
instrumental
record,
despite
the
cooling
effect
of
the
1991
>lt.
Pinatubo
volcanic
eruption.

1
GtC
=
1
billion
(109)
tonnes
of
carbon.

.~.
..

..
..
..
.
.­

~
..
­.
........
,­
.....
1.
..
..
....
...
..
...
...
.
.:
..
.....
..
..
.­
..
..
.~
..
9
..
.
.­

0
­
0
0
0
0
"

Night­
time
temperatures
over
land
have
generally
increased
more
than
daytime
temperatures.

Regional
changes
are
also
evident.
For
example,
the
recent
warming
has
been
'greatest
Over
the
mid­
latitude
continents
in
winter
and
spring,
with
a
few
areas
of
cooling,
such
as
the
North
Atlantic.
Ocean.
Precipitation
has
increased
over
land
in
high
latitudes
of
the
Northern
Hemisphere,
especially
during
the
cold
season.

Global
sea
level
has
risen
by
between
10
and
25
cm
over
the
past
100
years
and
much
of
the
rise
may
be
related
to
the
increase
in
global
mean
temperature.

There
are
inadequate
data
to
determine
whether
consistent
global
changes
in
climate
variability
or
weather
extremes
have
occurred
over
the
20th
century.
On
regional
scales
there
is
clear
evidence
of
changes
in
some
extremes
and
climate
variability
indicators
(e.
g.,
fe\
ver
frosts
in
several
widespread
areas;
an
increase
in
the
proportion
of
rainfall
from
extreme
events
over
the
contiguous
states
of
the
USA).
Some
of
these
changes
have
been
toward
greater
variability;
some4ave
been
toward
lower
variability.

The
1990
to
mid­
1995
persistent
warm­
phase
of
the
El
Niiio­
Southern
Oscillation
(which
causes
droughts
and
floods
in
many
areas)
was
unusual
in
the
context
of
the
last
120
years.

The
balance
of
evidence
suggests
a
discernible
human
influence
on
global
climate
Any
human­
induced
effect
on
climate
will
be
superimposed
on
the
background
"noze"
of
natural
climate
variability,
which
results
both
from
internal
fluctuations
and
from
external
causes
such
as
solar
variability
or
vo1ca~
n;
c
eruptions.
Detection
and
attribution
studies
attempt
to
distinguish
between
anthropogenic
and
natural
influences.
"Detection
of
change"
is
the
process
of
.demonstrating
that
an
observed
change
in
climate
is
highly
unusual
in
a
statistical
sense,
but
does
not
provide
a
reason
for
the
change.
"Attribution"
is
the
process
of
establishing
cause
and
effect
relations,
including
the
testing
of
competing
hypotheses.

Since
the
1990
IPCC
Report,
considerable
progress
has
been
made
in
attempts
to
distinguish
between
natural
and
anthropogenic
influences
on
climate.
This
progress
has
been
achieved
by
including
effects
of
sulphate
aerosois
in
addition
to
greenhouse
gases,
thus
leading
to
more
realistic
estimates
of
human­
induced
radiative
forcing.
These
have
then
been
used
in
climate
models
to
provide
more
complete
simulations
of
the
human­
induced
climate­
change
"signal".
In
addition,
new
simulations
with
coupled
atmosphere­
ocean
models
have.
provided
important
information
about
decade
to
century
time­
scale
natural
internal
climate
variability.
A
further
major
area
of
progress
is
the
shift
of
focus
from
studies
of
global­
mean
changes
to
comparisons
of
modelled
and
observed
spatial
and
temporal
patterns
of
climate
change.

The
most
important
results
related
to
the
issues
of
detection
and
attribution
are:

0
The
limited
available
evidence
from
proxy
climate
indicators
suggests
that
the
20th
century
global
mean
temperature
is
at
least
as
warm
as
any
other
century
since
at
least,
1400
AD.
Data
prior
to
1400
are
too
sparse
to
allow
the
reliable
estimation
of
global
mean
temperature.

e
Assessments
of
the
statistical
significance
of
the
observed
global
mean
surface
air
temperature,
trend
over
the
last
century
have
used
a
variety
of
new
estimafes
of
natural
internal
and.
externally
forced
variability.
These
are
derived
from
instrumental
data.
palaeodata,
simple
and
complex
climate
models,
and
statistical
models
fitted
to
observations.
Most
of
these
studies
have
detected
a
significant
change
and
show
that
the
observed
ivarming
trend
is
unlikely
to
be
entirely
natural
in
origin.

10
0
,'

'
I
0
`.
­

hlore
convincing
recent,
evidence
for
the
attribution
of
a
human
effect
on
climate
is
emerging
from
pattern­
based
studies,
in
which
the
modelled
climate
response
to
combined
forcing
by
greenhouse
gases
and
anthropogenic
sulphate
aerosols
is
compared
with
observed
geographical,
seasonal
and
vertical
patterns
of
atmospheric
temperature
change.
These
studies
show
that
such
pattern
correspondences
increase
with
time,
as
one
would
espect
as
an
anthropogenic
signal
increases
in
strength.
Furthermore,
the'probability
is
very
low
that
these
correspondences
could
occur
by
chance
as
a
result
of
natural
internal
variability
only.
The
vertical
patterns
of
change
are
also
inconsistent
with
those
expected
for
solar
and
volcanic
forcing.

Our
ability
to
quantify
the
human
influence
on
global
climate
is
currently
limited
because
the
expected
signal
is
still
emerging
from
the
noise
of
natural
variability,
and
because
there
are
uncertainties
in
key
factors.
These
include
the
magnitude
and
patterns
of
long­
term
natural
variability
and
the
time­
evolving
pattern
of
forcing
by,
and
response
to,
changes
in
concentrations
of
greenhouse
gases
and
aerosols,
and
land
surface
changes.
Xevertheless.
the
balance
of
evidence
suggests
that
there
iv
discernible
human
influence
on
global
climate.

Climate
is
expected
to
continue
t
o
change
in
the
future
The
IPCC
has
developed
a
range
of
scenarios,
IS92a­
f,
of
future
greenhouse
gas
and
aerosol
precursor
emissions
based
on
assumptions
concerning
population
and
economic
growth,
land­
use,
technological
changes,
energy
availability
and
fuel
mis
during
the
period
1990
to
2100.
Through
understanding
of
the
global
carbon
cycle
and
of
atmospheric
chemistry,
these
emissions
­
can
be
used
to
project
atmospheric
concentrations
of
greenhouse
gases
and
aerosols
and
the
perturbation
of
natural
radiative
forcing.
Climate
models
can
then
be
used
to
develop
projections
of
future
climate.

0
The
increasing
realism
of
simulations
of
current
and
past
climate
by
coupled
itmosphere­

change.
Important
uncertainties
remain.
but
these
have
been
taken
into
account
in
the
full
­.

6
;.
'ocean
climate
models
has
increased
our
confidence
in
their
use
for
projection
of
future
climate
"
range
of
projections
of
global
mea0
temperature
and
sea
level
change.

0
For
the
mid­
range
IPCC
emission
scenario,
IS92a,
assuming
the
"best
estimate"
value
of
climate
sensitivity'
and
including
the
effects
of
future
increases
in
aerosol,
modefs
project
an
increase
in
global
mean
surface
air
temperature
relative'to­
1990
of
about
2°
C
by
2100.
This
estimate
is
approximately
one
third
lower
than
the
"best
estimate"
in
1990.
This
is
due
primarily
to
lower
emission
scenarios
(particularly
for
C02
and
the
CFCs),
the
inclusion
of
the
cooling
effect
of
sulphate
aerosols,
and
improvements
in
the
treatment
of
the
carbon
cycle.
Combining
the
lowest
IPCC
emission
scenario
(IS92c)
with
a
"low"
value
of
climate
sensitivity
and
including
the
effects
of
future
changes
in
aerosol
concentrations
leads
to
a
.
projected
increase
of
about
1°
C
by
2100.
The
corresponding
projection.
for
the
highest
IPCC
scenario
(IS92e)
combined
with
a
"high"
value
of
climate
sensitivity
gives
a
warming
of
about
3.5"
C.
In
all
cases
the
average
rate
of
warming
would
probably
be
greater
than
any
seen
in
the
last
10,000
years,
but
the
actual
annual
to
decadal
changes
would
include
considerable
natural
variability.
Regional
temperature
changes
could
differ
substantially
from
the
global
mean
value.
Because
of
the
thermal
inertia
of
the
oceans,
only
50­
90%
o
f
the
eventual
equilibrium
tcil:
pcrntu­
c
ckzngc
~voulcl
have
been
realiscct
b
l
2100
and
tcmpcrat:::­
c
~:.
o::!
d
conticuc
to
increase
beyond
2100,
even
if
concentrations
of
greenhouse
gases
were
stabilised
by
that
time.

In
IPCC
reports,
climate
sensitivity
usually
refers
to
the
long
term
(equilibrium)
change
in
global
mean
surface
temperature
following
a
doubling
of
atmospheric
equivalent
CO,
concentration.
More
generally,
it
refers
t
o
t
h
e
equilibrium
change
in
surface
air
temperature
following
a
unit
change
in
radiative
forcing
r
W
m
­2
).
.~

..
..
11
,
­.
..
....
...
..
..".
~­
.
..
..
..
..
..
..
...
..,.
.
.
...
....
.~.
.
­
..
..,
.~
......
­.
~.
i
­
.
".
­
,_
.....
...
...
...
..,
~
..
..
..
...
...
.....
..
12.
..
..
...
...
..
..
..
.....
....
..
....
...
%'
.
:
.:
.
,
....
.....
..
­
......
.....
......
e
Sustained
rapid
climate­
change
could
shift
the
competitive
balance
among
species
and
even
lead
to
forest
dieback,
altering
the
terrestrial
uptake
and
release
of
carbon.
The
magnitude
is
uncertain,
but
couid
be
between
zero
and
200
.GtC
over
the
next
one
to
two
centuries,
depending
on
the
rate
of
climate
change.

There
are
still
many
uncertainties
Many
factors
currently
limit
our
ability
to
project
and
detect
future
climate
change.
In
particular,
to
reduce
uncertainties'further
work
is
needed
on
the
following
priority
topics:
I
0
estimation
of
future
emissions
and
biogeochemical
cyciing
(including
sources
and
sinks)
of
greenhouse
gases,
aerosols
and
aerosol
precursors
and
projections
of
future
concentrations
a
n
d
r
a
d
i
a
t
i
v
e
I
0
representation
of
climate
processes
in
aodels,
especially
feedbacks
associated
with
clouds,
.oceans,
sea
ice
and
vegetation,
in
order
to
improve
projections
of
rates
and
regional
patterns
of
climate
change:

0
systematic
collection
of
long­
term
instrumental
and
proxy
observations
of
climate
system
variables
(e.
g.,
solar
output,
atmospheric
energy
balance
components,
hydrological
cycles,
ocean
characteristics
and
ecosystem
changes)
for
the
purposes
of
model
testing,
assessment
­
of
temporal
and
regional
variability
and
for
detection
and
attribution
studies.

Future
unexpected,
large
and
rapid
climate
system
changes
(as
have
occurred
in
the
past)
are,
by
their
nature,
difficult
to
predict.
This
implies
that
future
climate
changes
may
also
involve
.
"surprises".
In
particular
these
arise
from
the
non­
linear
n'ature
of
the
climate
system.
iVhen
rapidly
forced,
non­
linear
systems
are
especially
subject
to
unexpected
behaviour.
Progress
can
be
made
by
investigating
non­
linear
processes
and
sub­
components
of
the
climatic
system.
`Examples
of
such
non­
linear
behaviour
include
rapid
circulation
changes
in
the
North
Atlantic
'

and
feedbacks
associated
with
terrestrial
ecosystem
changes..
3
..
.\
..
.
..
.
...
.­
­
..
..
..
..
.
­
..
.
..
.
­.
..
.
:.
..
.
.
.
..
.
..
,
..
..

.
.­
..
.
.
..

­
A.
Introduction
The
IPCC
Scientific
Assessment
Working'
Group
@$
GI)
was
established
in
1988
to
assess
available
information
on
the
science
of
climate
change,
in
particular
that
arising
from
human
activities.
In
performing
its
assessments
the
Working
Group
is
concerned
Ivith:

*
developments
in
the
scientific
understanding
of
past
and
present
climate.
of
climate
variability.
of
climate
predictability
and
of
climate
change
including
feedbacks
from
climate
impacts;

0
progress
in
the
modelling
and
projection
of
global
and
regional
climate
and
sea
level
change;
3
observations
of
climate,
including
past
climates.
and
assessment
of
t
r
e
n
d
s
a
n
d
anomalies;

gaps
and
uncertainties
in
current
knowledge.

The
first
Scientific
Assessment
in
1990
concluded
that
the
increase
in
atmospheric
concentrations
of
greenhouse
gases
since
the
pre­
industrial
period'
h
a
d
a
l
t
e
r
e
d
t
h
e
e
n
e
r
g
y
b
a
l
a
n
c
e
of
the
Earth/
atmosphere
and
that
gbbal
warming
would
result.
Model
simulations
of
global
warming
due
to
t
h
e
,
observed
increase
of
greenhouse
gas
concentrations
over
the
past
century
tended
towards
a
central
estimate
of
about
1°
C
while
analysis
of
the
instrumental
temperature
record,
on
the
other
hand.
revealed
warming
of
around
0.5'C
over
the
same
period.
The
1990
report
concluded:
"The
size
of
this
warming
is
broadly
consistent
with
predictions
of
climate
models,
but
it
is
also
of
the
same
magnitude
as
natural
climate
variability.
Thus
the
observed
increase
could
be
largely
due
to
this
natural
variability:
alternatively
this
variability
and
other
human­
factors
could
have
offset
a
still
larger
human­
induced
greenhouse
warming."
A
primary
concern
identified
by
IPCC
(1990)
was
the
espected
continued
increase
in
greenhouse
gas
concentrations
as
a
result
of
human
activity,
leading
to
significant
climate
change
in
the
coming
century.
The
projected
changes
in
temperature,
precipitation
and
sui:
ritoisrure
viere
~w
t
u
n
i
f
o
n
o;
'cr
the
g!
o5..
Anthropogenic
zerosols
were
recognised
as
a
possible
source
of
regional
cooling
but
no
quantitative
estimates
of
their
effects
were
available.
The
IPCC
Supplementary
Report
in
1992
confirmed.
or
found
no
reason
to
alter,
the
major
conclusions
of
.K
C
(1990).
It
presented
a
new
16
..
..
.
..

..
..
...
.?
..
range
of
global
mean
temperature
projections
based
on
a
new
set
of
IPCC
emission
scenarios
(IS92
a
to
0
and
beported
progress
in
quantifying
the
effects
of
anthropogenic
aerosols.
Ozone
depletion
due
to
chlorofluorocarbons
(CFCs)
was
recognisecl
as
a
cause
of
negative
radiative
forcing.
reducing
the
global
importance
of
CFCs
as
greenhouse
gases.
The
1994
IVGI
report
on
Radiative
Forcing
of
Climate
Change
provided
a
detailed
assessnmt
of
t
h
e
g
l
o
b
a
l
c
a
r
b
o
n
c
y
c
l
e
a
n
d
of
aspects
of
atmospheric
chemistry
governing
the
abundance
of
non­
COz
greenhouse
gases.
Some
pathways
that
would
stabilise
atmospheric
greenhouse
gas
concentrations
were
esamined.
and
new
or
revised
calculations
of
Global
IVarming
Potential
for
3s
species
were
presented.
The
growing
literature
on
processes
governing
the
abundance
and
racliatiye
properties
of
aerosols
was
examined
in
considerable
detail.
including
new
information
on
the
climatic
impact
of
the
1991
eruption
of
hlt.
Pinatubo.
The
Second
IPCC
Assessment
of
the
Science
of
Climate
Change
presents
a
comprehensive
assessment
of
climate
change
science
as
of
1995.
including
updates
of
relevant
material
in
all
rime
'
preceding
reports.
Key
issues
examined
in
the
Second
Assessment
concern
the
relative
magnitude
of
human
and
natural
factors
in
driving
changes
in.
climate,
including
the
role
of
aerosols;
tvhetlwr
a
human
influence
on
present­
day
clinlatc?
can
be
detected:
and
the
estimation
of
future
climatt.
and
sea
level
change
at
both
global
and
continental
scales.
The
United
Nations
Framework
Convcntion
on
Climate.
Change
(FCCC)
.uses.
the
term
"climate
change"
to
refer
esclusively
to
change
brought
about
by
human
activities.
.4
more
generic
usagt'
is
common
in
the
scientific
community
where
it
is
necessary
to
be
able
to
refer
to
change
arising
from
any
source.
In
particular
scientists
refc.
r
to
past
climate
change
and
address
the
complcs
issue
of
separating
natural
and
human
causes
in
currently
observed
changes.
However.
the
climate
projections
covered
in
this
document
relate.
only
to
future
climate
changes
resulting
from
human
influences.
since
it
is
not
yet
possible
to
predict
the
fluctuations
ciuc
to
volcanu~~
s
anci
oriwr
natur,!
l
i11?~~
1tai:~,~~
5.
Consequently
the
use
of
the
term
"climate
change"
here.
when
referring
to
future
change.
is
essentially
the
same
as
the
usage
adopted
in
the
FCCC.

1
The
pre­
industrial
period.
is
defined
as
the
several
centuries
preceding
1750.

..
.
r
..
.......
B.
Greenhouse
Gases,

Forcing
­Aerosols
and
their
Radiative
Human
activities
are
changing
the
atmospheric
concentrations
and
distributions
of
greenhouse
gases
and
aerosols.
These
changes
can
produce
a
radiative
forcing
by
changing
either
the
refleaion
or
absorption
of
solar
radiation,
or
the
emission
and
absorption
of
terrestrial
radiation
(see
Bos
1).
Information
on
radiative
forcing
was
extensively
reviewed
i
n
iPCC
(1994).
Summaries
of
the
information
in
that
report
and
new
results
are
presented
here.
The
most
significant
advance
since
IPCC
(1994)
is
improved
understanding
of
the
role
of
aerosols
and
their
representation4
climate
models.

B
.l
Carbon
dioxide
(COz)
CO,
concentrations
have
increased
from
about
250
ppmv
in
pre­
industrial
times
to
35s
ppmv
in
1994
(Table
1,
and
Figure
la).
There
is
no
doubt
that
this
increase
is
largely
due
to
human
activities.
in
particular
fossil
fuel
combustion,
but
also
land­
use
conversion
and
to
a
lesser
extent
cement
production
(Table
2).
The
increase
has
led
to
a
radiative
forcing
of
about
+1.6
iYm­
2
(Figure
2).
Prior
to
this
recent
increase,
CO2
concentrations
over
the
past
1000
years.
a
period
tvhen
global
climate
was
relatively
stable,
fluctuated
by
about
$10
ppmv
around
2S0
pprnv.
The
annual
growth
rate
of
atmospheric
CO,
concentration
was
low
during
the
early
1990s
(0.6
ppmviyr
in
299182).
Hon'ever,
recent
data
indicatc
that
the
growth
rate
is
currently
comparable
to
that
averaged
over
the
19SOs.
around
1.5
ppmviyr
(Figure
lb).
Isotopic
data
suggest
that
the
low
growth
rate
resulted
from
fluctuations
in
the
exchanges
of
CO?
between
the
atmosphere
and
both
the
ocean
and
the
terrestrial
biosphere,
possibly
resulting
from
climatic
and
biospheric
variations
following
the
eruption,
of
blt.
Pinatubo
in
June
i991.
While
understanding
these
short­
term
fluctuations
380
­

(a)
330
Figure
I:
(a)
CO,
concentrations
6
over
the
past
1000
yearsfiom
e
057
E
Siple
I
360
A
047
­
7
360
­
ice
core
records
(D47.
057.
.*

i
(since
1958)
f
r
o
m
M
a
u
n
a
Loa.
­
­
Siple
and
South
Pole)
and
'

­
South
Pole
.I
340
­.
­
­
Mauna
Loa
c
Hawaii,
measurement
s
i
t
e
.
A
l
l
a
­One
hundred
year
....
340
­
Fossil
CO,
emissions
t
320
­
ice
core
measurements
were
taken
in
Antarctica.
The
smooth
Y
curve
is
based
on
a
hundred
year
running
mean.
The
rapid
since
the
onset
of
industrialisation
is
evident
and
­
.'
C
­

320
­
running
mean
3s
=
330
./.­
e
.­
­
­
W
2
"
1900
­
1950
Year
increase
in
CO,
concentration
0
,.

$
300
­

c
.­

....
260
800
1000
1200
1400
1600
1800
.
2000
Year
has
followed
closely
the
increase
in
CO,
emissions
from
fossil
fuels
(see
inset
of
period
from
1850
onwards).
(b)
Growth
.
rate
of
CO,
concentration
since
1958
in'ppmdyr
at
Mauna
Loa.
The
smooth
curue
shows
the
same
data
butfiltered
to
.

suppress
variations
on
time­
scales
less
than
approximately
10
years.
~

..................................
1958
60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
90
92
94
g
Year
...
..
I
...
..........
..
.
.­
,
..
Figure
2:
Estimates
of
the
globally
and
annually
averaged
anthropogenic
.radiative
forcinflin
tI.
5n­
Z)
due
to
changes
in
concentrations
of
.

greenhouse
gases
and
aerosols
from
pre­
industrial
times
to
che
present
(1992)
and
to
natura1,
changes
in
solar
output
from
1650
to
the
present.
The
height
ofthe
rectangular
bar
indicates
a
mid­
range
estimate
ojthe
forcing
whilst
the
error
bars
show
an
estimctte
of
the
uncertainty
range.
based
largely
on
the
spread
of
published
cakes;
the
"conjidence
level"
indicates
the
author's
confidence
thar
the
actual
forcing
lies
within
this
error
bar:
The
contriblctions
of
individual
gases
to
the
direct
greenhortse
forcing
is
indicated
on
thejirst
bar:
The
indirect
greenhouse
forcings
associated
with
the
depletion
of
stratospheric
ozone
and
the
increased
concentration
of
I
J
I
Stra:
ospheric
~~
Tropospheric
aerosols
­
direct
effect
&
Fossil
fuel
:
ozone
"P
I
ozone
1
,
Tropospheric
aerosols
­
indirect
effect
9
Confidence
level
High
Low
Low
Low
Very
Very
Very
Very
low
low
low
low
tropospheric
ozone
are
shown
in
the
second
and
third
bar
respectively.
The
direct
contributions
of
indiuidual
tropospheric
aerosol
component
are
grouped
into
the
next
set
of
three
bars.
The
indirect
aerosol
eflect,

'
arising
from
the
induced
change
in
cloud
properties,
is
shown
next:
quantitative
understanding
of
this
process
is
very
limited
at
present
and
hence
no
bar
representing
n
mid­
range
estimate
is
show.
TheJnal,
bar
shows
the
estimate
of
the
changes
in
radiative
.
.
forcing
due
to
variations
in
solar
output.
The
forcing'
associated
with
stratospheric
aerosols
resulting
jrom
volcanic
eruptions
is
not
shown,
as
i
t
i
s
very
variable
.
over
this
time
period.
Xote
that
there
are
substantial
dgerences
in
the
geographical
distribution
of
the
forcing
due
to
the
u1ell­
mixed
greenhouse
gases
(mainly
CO,
1\
50,
CH,
ancl
the
halocarbons)
and
that
clue
to
ozone
ancl
aerosols.
which
codd
lead
to
signijicant
cliflerences
in
their
respectiae
global
and
regional
climate
responses.
For
this
reason.
the
negatice
radiatire
forcing
due
to
aerosols
should
not
necessarily
be
regarded
as
nn
oflset
against
the
greenhortse
gas
forcing.
*
is
important,
fluctuations
of
a
few
years'
duration
a
r
e
n
o
t
r
e
l
e
v
a
n
t
to
projections
of
future
concentrations
or
emissions
aimed
at
estimating
longer
time­
scale
changes
to
the
climate
system.
The
estimate
of
the
1980s'
carbon
budget
(Table
2)
remains
essentially
unchanged
from
IPCC
(1
99­
11.
\L'hile
recent
data
on
anthropogenic
emissions
are
available,
there
are
insufficient
analyses
of
the
other.
fluses
to
allotv
an
update
of
this
decndal
budget
to
include
the
early
years
of
the
1990s.
The
net
release
of
carbon
from
tropical
land­
use
change
(mainly
forest
clearing
minus
regrolvth)
is
roughly
balanced
by
carbon
accumulation
in
other
land
ecosystems
due
to
forest
regrowth
outside
the
tropics,
and
by
trailsfer
to
other
reservoirs
stim
lated
by
CO:,
and
nitrogen
fertilisation
and
by
J
ecadal
time­
scale
clinlatic
effccts.
Model
results
suggest
that
during
the
19SOs,
CO,
fertilisation
resulted
in
a
transfer
of
carbon
from
thc
atmosphere
to
the
biosphere
of
0.5
to
2.0
GtC/
yr
and
nitrogen
fcrtilisation
resulted
in
a
I
transfer
of
carbon
from
the
atmosphere
to
thc
biosphere
of
between
0.2
and
1.0
GtC/
yr.
CO:,
is
removed
from
the
atmosphcre
by
a
number
of
processes
that
operate
on
different
time­
scales,
and
is
subsequently
transferrcd
to
various
reservoirs.
some
of
which
eyftually
return
CO,
to
the
atmosphcre.
Somc
simile
analysis
of
COz
changes
have
used
the
concept
of
a
single
characteristic
time­
scale
for
this
gas.
Such
an
I­.
a
Lses
a
r
e
of
limited
value
because
a
single
tinlc­
scaie
cannot
capture
the
behaviour
of
CO,
under
differellt
emission
scenarios.
This
is
in
contrast
to
methane,
for
example.
ivhose
atmospheric
lifetime
is
dominantly
controlled
by
a
single
process:
osiclntion
by
OH
in
the
atmosphere.
For
CO:,
the
fastest
process
is
uptake
into
vegetation
and
the
surface
layer
of
the
oceans
which
occurs
over
a
fetv
years.
Various
other
sinks
operate
on
the
century
time­
scale
(e.
g.,
transfer
to
soils
and
to
the
deep
ocean)
and
so
have
a
less
immediate.
but
no
less
important.
effect
on
the
atmospheric
concentration.
IVithin
30
years
about
4060%
of
the
COP
currently
released
to
the
atmosphere
is
removed.
However.
i
f
emissions
were
reduced.
the
CO,
in
the
vegetation
and
ocean
surface
water
tvould
soon
equilibrate
with
that
in
the
atmosphere,
and
the
rate
of
removal
~vould
then
be
determined
by
the
slower
response
of
woody
vegctation.
soils.
and
transfer
into
the
deeper
layers
of
the
ocean:
Consequently,
most
uf
the.
escess
atmospheric
CO,
would
be
removed
over
about
a
century
although
a
portion
would
remain
airborne
for
thousands
of
years
because
transfer
to
the
ultimate
sink
­
ocean
sediments
­
is
very
slow.
There
is
large
uncertainty
associated
with
,the
f
u
t
u
r
e
r
o
l
e
of
the
terrestrial
Table
2:
Annrtul
auernge
anthropogenic
carbon
budget
for
19SO
to
19S9.
CO,
sources.
sinks
and
storage
in
tf1.
e
atmosphere
are
expressed
in
CtC/
yr.

C
0
2
sources
(1)
Emissions
from
fossil
fuel
combustion
and
5.5
2
0.5*
cement
production
(2)
ru'et,
emissions
from
changes
in
tropical
land­
use
1.6
*
1.0@
(3)
Total
anthropogenic
emissions
=
(1)+(
2)
7.1
2
1.1
20
biosphcrc
in
the
global
carbon
budgct
for
sevcral
reasons.
First.
future
rates
of
deforestation
and
regrowth
in
the
tropics
and
mid­
latitudes
arc
difficutt
to
predict.
Second.
mechanisms
such
as
CO,
f
e
r
t
i
l
i
s
a
t
i
o
n
r
e
m
a
i
n
p
o
o
r
l
y
quantified
at
the
ecosystem
.level.
Over
d
e
c
a
d
e
s
t
o
c
e
n
t
u
r
i
e
s
.
a
n
t
h
r
o
p
o
g
e
n
i
c
c
h
a
n
g
e
s
i
n
atmospheric
CO,
c
o
n
t
e
n
t
a
n
d
climate
may
also
alter
the
global
distribution
of
ecosystem
types.
.

Carbon
couid
be
released
rapidly
f
r
o
m
a
r
e
a
s
w
h
e
r
e
f
o
r
e
s
t
s
d
i
e
,
although
regrowth
could
eventually
sequester
much
of
this
carbon.
.

EsLiil1rLtxs
OF
ibis
Ios:,
rangtb
from
near
zero
to,
at
lobv
probabilities,
as
much
as
200
GtC
owr
the
nest
one­
to­
bvo
centuries,
depending
on'
thz
rate
of
climate
change.
The
marine
biota
both
respond
to
and
can
influence
climate
change.
.
Marine
biota
play
a
critical
role
in
depressing
the
atmospheric
CO,
concentration
significantly
below
its
equilibrium
state
in
the
absence
of
biota.
Changes
in
nutrient
supply
to
the
surface
ocean
resulting
from
changes
in
ocean
circulation,
coastal
runoff
and
atmospheric
deposition.
and
changes
in
the
amount
of
sea
ice
and
cloudiness,
have
the
potential
to
affect
marine
.
1900
1
,
,
,
,
,
,
,
I
b
i
o
g
e
o
c
h
e
m
i
c
a
l
would
be
­
e
x
p
e
c
t
e
d
t
o
h
a
v
e
a
n
i
m
p
a
c
t
(a
t
p
r
e
s
e
n
t
unquantifiable)
on
the
cycling
of
CO,
a
n
d
t
h
e
production
of
other
climatically
important
trace
Year
phytoplankton
growth
in
certain
ocean
areas.
However.
it
is
not
likely
that
iron
fertilisation
of
CO,
uptake
by
phytoplankton
can
be
used
to
draw
down
atmospheric
CO,:
even
massive
continual
seecling
of
B.
2
Methane
(CHb)
10­
15%
of
the
world
oceans
(the
Southern
Ocean)
Methane
is
another
naturally
occurring
greenhouse
,
until
2100,
i
f
it
worked
with
100%
efficiency
and
no
gas
whose
concentration
in.
the
atmosphere
is
opposing
side­
effects
(e.
g.,
increased
N
2
0
growing
as
a
result
of
human
activities
such
;IS
production).
would
reduce
the
atmospheric
CO,
agriculture
and
waste
disposal.
and
fossil
fuel
­
build­
up
projected
by
the
IPCC
(1990)
"Business­
as­
production
and
use
(Table
3).
usual"
emission
scenario
by
less
than
10%.
1
5
5
0
""'
"'
I
~~~~
a4
86
aa
90
92
94
gases.
It
has
been
suggested
that
a
lack
of
iron
linlits
F
W
e
3
:
Glo'bal
methane
concentrations
(ppbL9for
IQS3
(0
1994.
Concentrations
observed
at
hlonld
Boy,
Canacla
are
also
shown.

Table
3:
Estimuted
sources
and
sinks
of
methane&
1960
to
1990.
AllJigures
are
in
TgtCCH&
yr.
The
current
global
atmospheric
burden
of
CH,
is
about
5000
TgCCHd.

(a)
Observed
atmospheric
increase,
estirnatedsinks
and
sources
derived
to
b
a
l
a
n
c
e
t
h
e
b
u
d
g
e
t
..

.,
Individual
estimates
To
tal
..

Atmospheric
increase*
37
(35­
40)
Sinks
of
atmospheric
CH4:
tropospheric
OH
.
,.
,.
490
(405­
575)
..

stratosphere
40
(32­
48)

­
'
soils
..

.
.
:
30
(15­
45)
­..
.....
..

Total
atmospheric
sinks.
.......
:...
;
..;.__
..
:
:...
c
.
..;
.....
_.
....
...
l..
.
:.:
.:
..
.
~...
......
..
I:
~
.
..
....
.$.
..~
>.
i"..
..........
..
....
..........
:.
...:...
560
(460­
660),
.,

::
.,;...$.
L.
597
(495­
700)
'
.i
.
Implied
sources.(
sinks
..
+
atmospheric
increase)
I
:::
.:.:
I
..
......
.......
:.
=
...
.
­
,
.
.
­
..­.
r..
..
­.
.............
_.
­:.
.
......
..
.
.,
:
.,.
..
Global
average
methane
concentrations
increased
by
6%
over
the
decade
starting
in
1984
(Figure
3).
­
?ts
concentration
in
1991
was
about
1720
ppbv,
145%
greater
than
the
pre­
industrial
concentration
of
700
ppbv
(Table
1.
Figure
3).
Over
the
last
20
years,
there
has
been
a
decline
in
the
methane
growth
rate:
in
the
late
1990s
the
concentration
\vas
increasing
by
about
20
ppbv/
yr,
during
the
19SOs
the
growth
rate
dropped
to
9­
13
ppbvlyr.
Around
the
middle
of
1992,
methane
concentrations
briefly
stopped
growing.
but
since
1993
the
global
growth
rate
has
returned
to
about
8
ppbv/
yr.
Individual
methane
sources.
are
not
well
quantified.
Carbon
isotope
measurements
indicate
that
about
20%
of
the
totat.
annual
methane
emissions
are
related
to
the
prodkdtion
and
use
of
fossil
fuel.
In
total,
anthropogenic
activities
are
responsible
for
about
GO­
SO%
of
current
methane
emissions
(Table
3).
Methane
emissions
from
natural
wetlands
appear
to
contribute
about
20%
to
the
global
methane
emissions
to
the
atmosphere.
Such
emissions
tvill
probably
increase
with
global
warming
as
a
result
of
greater
microbial
activity.
In
1992
the
direct
radiative
forcing
due
to
the
increase
­
in
methane
concentration
since
pre­
industrial
times
was
about
+0.47
W
m
­2
(Figure
2):
Changes
in
the
concentratih
of
methane
have
clcarly
identified
chemical
feedbacks.
The
main
removal
process
for
methane
is
reaction
with
the
hydrosyl
radicai
(OH).
Addition
of
methane
to
the
a
t
m
o
s
p
h
e
r
e
r
e
d
u
c
e
s
t
h
e
.
concentration
of
tropospheric
01­
1
which'can
in­
turn
feed
back
and
reduce
the
rate
of
methane
removal.
The
adjustment
time
for
a
pulse
of
methane
adclcd
to
the
atmosphere
has
been
revised
to
12
(k3)
years
(compared.
with
14.5
(r2.5)
years.
in
IPCC
(1931)).
Two
factors
are
responsible
for
'the
change:
(a)
a
new
estimate
for
the
chemical
removal
rate
(11%
faster);
and
(b)
inclusion
of
the
uptake
of
methane
by
soils.
The
revised
global
sink
strength
is
560
(+
loo)
Tg(
CHJ/
year.
higher
than
the
1994
estimate.
but
still
consistent
with
the
previous
range
of
global
source
strength.

8.3
Nitrous
oxide
(NzO)
There
are
many
small
sources
of
nitrous
oxide,
boLh
~latural
a
d
antllropogullic,
\vhich
art'
ciii'iicuit
to
quantify.
The
main
anthropogenic
sources
are
from
agriculture
and
a
number
of
industrial
p
r
o
c
e
s
s
e
s
(e
.g
.,
a
d
i
p
i
c
a
c
i
d
a
n
d
n
i
t
r
i
c
a
c
i
d
production).
X
best
estimate
of
the
current
(19SOs)
anthropogenic
emission
of
nitrous
oside
is
3
to
S
22
TgWyr.
Natural
sources
are
poorly
quantifiecl.
but
are
probably
twice
as
large
as
anthropogenic
sources.
Nitrous
oxide
is­
removed
mainly
by
photolysis
(breakdown
by
.s
u
n
l
i
g
h
t
)
i
n
t
h
e
stratosphere
and
consequently
has
a
.
long
lifetime
(about
120
years).
Although
sources
cannot
be
well
quantified.
atmospheric
measurements
and
evidence
from
ice
cores
show
.that
the
atmospheric
abundance
of
nitrous
oxide
has
increased
since
the
pre­
industrial
era,
most
likely
oiving
to
human
activities.
In
1994
atmospheric
levels
of
nitrous.
oside
were
about
312
ppbv:
pre­
industrial
levels
were
about
275
ppbv
(Table
1).
The
1993
grolvth
rate
(approsimately
0.5
ppbv/
yr)
was
lotver
than
that
observed
in
the
late
19SOs
and
early
1990s
(approsimately
0.8
ppbv/
yr).
but
these
short­
term
changes
in
groivth
rate
are
within
the
range
of
variability
seen
on
decadal
time­
scales.
The
radiative
forcing
due
to
the
change
in
nitrous
oxide
since
pre­
industrial
times
is
about
+0.14
Wm­
2
(Figure
2).

8.4
Halocarbons
and
other
­

halogenated
compounds
'

Nalocarbons
arc
carbon
compounds
containing
fluorine,
chlorine,
bromine
or
iodine.
Many
of
these
are
effective
greenhouse
gases.
For
most
o
f
these
compounds.
human
activities
are
the
sole
sourcc.
Halocarbons
that
contain
chlorine
(CFCs
and
HCFCs)
and
bromine
(halons)
cause
ozone
depletion.
and
their
emissions
arc
controlled
under
the
Montreal
Protocol
and
its
Adjustments
an,
d
Amendments.
As
a
result.
growth
rates
in
,the
concentrations
of
many
of
these
compounds
have
already
fallen
(Figure
1)
and
the
radiative
impact
of
these
coinpounds
will
slon.
ly
decline
over
the
nest
century.
Thc
contribution
to
direct
radiative
forcing
due
to
concentration
increases
of
these
CFCs
and
HCFCs
since
preindustrial
times
is
about
+0.25
W
n
­2
.

Halocarbons
can
also
esert
an
indirect
negative
radiative
forcing
through
their
depletion
of
stratospheric
ozone
(see
Section
B.
5.2).
Perfluorocarbons
(PFCs.
e.
g.,
CF,.
C2F,
J
and
sulphur
hexafluoride
[SF,)
are
removed
very
slocvly
from
the
atmosphere
with
estimated
lifetimes
greater
than
1000
years.
As
a
result.
effectively
all
emissions
accumulate
i
n
the
amwspheru
and
ivili
concilluc
to
influence
climate
for
thousands
of
years.
Although
the
radiative
forcing
due
to
concentration
increases
of
these
compounds
since
pre­
industrial
times
is
small
(about
t0.01
IVm­
2).
i
t
may
become
significant
in
the
future
if
Concentrations
continue
t
o
increase.

,.
.
I
..

..

.~
i
I
.,
Hydrofluorocarbons
(HFCsl
are
being
use$
to
replace
ozone­
depleting
substances
in
some
appiications;
their­
concentrations
and
radiative
impacts
are
currently
small.
If
emissions
increase
as
envisaged
in
Scenario
IS92a.
they
would
contribute
about
3%
of
the
total
radiative
forcing
from
all
greenhouse
gases
by
the
year
2100.

8.5
Ozone
(03)
Ozone
is
an
important
greenhouse
gas
present
in
both
the
stratosphere
and
troposphere.
Changes
in
ozone
cause
radiative
forcing
by
influencing
both
solar
and
terrestrial
radiation.
The
net
radiative
forcing
is
strongly
dependent
on
the
vertical
distribution
of
ozone
change
and
is
particularly
sensitive
to
changes
around
the
tropopause
level,
where
trends
are
difficult
t
o
estimate
due
to
a
lack
of
reliable
observations
and
the
very
large
natural
variability.
The
patterns
of
both
tropospheric
and
stratospheric
ozone
changes
are
spatially
variable.
Estimation
of
the
radiative
forcing
due
10
changes
in
ozone
is
thus
more
complex
than
for
the
wetl­
mixed
greenhouse
gases.

8.5.1
Tropospheric
Ozone
?n
the
troposphere.
ozone
is
produced
during
the
oxidation
of
methane
and
from
various
short­
lived
precursor
gases
(mainly
carbon
monoxide
(CO):
'
nitrogen
oxides
(NOs)
and
non­
methane
hydrocarbons
(NMHC)).
Ozone
is
also
transportrd
into
thc
tropospherc
from
the
stratosphere.
Changes
in.
troposphcric
ozone
concentration
are
spatially
variable.
both
regionally
and
vertically,
making
assessment
of
global
longlttnn
trends
dificult.
In
the
Northern
.Iiernisphere.
thero
is
some
evidencc
that
tropospheric
ozone
concentrations
hale
increased
since
1900.
with
strong
evidence
that
this
has
occurred
in
many
locations
since
the
1960s.
However.
the
observations
of
the
most
recent
decade
show
that
the
upward
trend
has
slo&
d
significantly
or
stopped.
hlddel
simulations
and
the
limited
observations
'together
suggest
that
ozone
concentrations
throughout
the
troposphere
may
have
doubled
in
the
Northern
Hemisphere
since
pre­
industrial
times,
an
increase
of
about
25
ppbv.
In
the
Southern
Hemisphere,
there
are
insufiicient
dak?
to
determine
iftropospheric
ozoue
has
changed.
esccpt
i
t
the
South
Pole
whew
a
derreasc
has
been
observed
since
the
mid­
1980s.
Changes
in
tropospheric
ozone
have
potentially
important
consequences
for
radiative
forcing.
The
calculated­
global
average
radiative
forcing
due
to
the
increased
concentration
since
pre­
industrial
times
is
+0.4
(10.2)
Wm­
2.
,.
Year
4
Figure
4:
Global
CFC­
11
concentrations
(pptc)
for
1975
to
1994.
As
one
of
the
ozone­
depleting
gases.
the
emissions
of
C
F
q
l
l
are
controlled
under
the
hfontrenl
Protocol
and
its
Adjustments
and
Amendments.
Obsercations
at
some
individual
measurement
sites
are
also
shown.

B.
5.2
Stratospheric
Ozone
Decrcases
in
stratospheric
ozone
have­
occurred
s
i
n
c
e
t
h
e
1970s.
.principally
in'
tht?
lower
stratosphere.
The
most
obviws
feature
is
the
annual
appearance
of
the
Antarctic
"ozone
I~
olc"
in
September
and
October.
The
­October
averaic
total
ozone
values
over
Antarctica
are
50­
TO%
loncr
than
those
observed
in
the
1960s.
Statistically
significant
losses
in
total
ozone
have
also
been
observed
in
the
mid­
latitudes
of
both
hemispheres.
Little
or
no
downward
trend
in
ozonc
has
been
observed
in
the
tropics
(20"
N­
ZWS).
The
weight
of
recent
scientific
evidence
strengthens
the
previous
conclusion
that
ozone
loss
is
due
largely
to
anthropogenic
chlorine
and
bromine
compounds.
Since
the
stratospheric
abundances
of
chlorine
and
.
bromine
are
expected
to
continue
to
grow
for
a
few
more
years
before
they
de'cline
(see
Section
B.
4),
stratospheric
ozone
losses,
are
expected
to
peak
near
the
end
of
the
century.
with
a
gradual
recovery
throughout
the
first
half
of
the
21st
century.
'
The
joss
of
ozone
in
the
1ower.
strarosphere
over
the
past
15
to
20
years
has
led
to
a
globally
averaged
radiative
forcing
of
about
­0.1
LVn1.2.
This
negative
radiative
forcing
represents
an
indirect
effect
of
.anthropogenic
chlorine
and
bronline
cornpoul+
s.

..­
8.6
Tropospheric
and
stratospheric
B.
7
Summary
of
radiative
forcing
­
aerosols
Globally
averaged
radiative
forcing
is
a
useful
Aerosol
is
a
term
used
for
particles
and
very
small
droplets
of
natural
and
human
origin
that
occur
in
the
atmosphere;
they
include
dust
and
other
particles
which
can
be
made
up
of
many
different
chemicals.
.4erosols
are
produced
by
a
variety
of
processes,
both
natural
(including
dust
storms
and
volcanic
activity)
and
anthropogenic
(including
fossil
fuel
and
biomass
burning).
Aerosols
contribute
to
visible
haze
and
can
cause
a
diminution
of
the
intensity
of
sunlight
at
the
ground.
Aerosols
in
the
atmosphere
influence
the
radiation
balance
of
the
Earth
in
two
ways:
(i)
by
scattering
and
absorbing
radiation
­the
cf?&
cf
effect,
and
(ii)
by
modifying
the
optical
properties,
amount
and
lifetime
of
clouds
­
the
indirect
effect.
Although
some
aerosols.
such
as
soot,
tend
to
warm
the
surface.
the
net
climatic
effect
of
anthropogenic
aerosols
is
believed
to
be
a
negative
radiative
forcing.
tending
to
cool
the
surface
(see
Section
6.7
and
Figure
2).
Most
aerosols
with
anthropogenic
sources
are
found
in
the
lower
troposphere
(below
2
km).
A
e
r
o
s
o
l
s
u
n
d
c
r
g
o
c
h
c
t
n
i
c
a
l
a
n
d
p
h
y
s
i
c
a
l
transformations
in
the
atmosphare,
especially
withiri.
clouds.
and
are
removed
iiirgely
by
precipitation.
Conscqucntly
aerosols
in
tha
­lower
troposphere
typically
have
residence
times
of
a
fcw
days.
Because
of
their
short
lifetime,
aerosols
i
n
the
lower
tropnspherc
are
'distributed'
inhomogeneously
with
masinla
'close
to
the
natural
(especially
desert)
and
anthropogenic
(especially
iildustrial
and
biomass
combustion)
source
regions.
Aerosol
particles
resulting
from
volcanic
activity
can
rcach
the
stratosphere
where
they
are
transported
around
tho
.

globe
over
tnaily
months
or
years.
The
radiative
forcing
due
to
aerosols
depends
on
the
size,
shape
and
chemical
composition
of
the­
particles
and
the
spatial
distribution
of
the
aerosol.
\Vhile
these
factors
are
comparatively
well­
known
for
stratospheric
aerosols.
there
remain
many
uncertainties
concerning
tropospheric
aerosols.
Since
IPCC
(1994);
there
have:
been
several
a
d
v
a
n
c
e
s
i
n
u
n
d
e
r
s
t
a
n
d
i
n
g
t
h
e
i
m
p
a
c
t
o
f
.tropospbcric
iterosols
on
rlimate.
Thcse
includc:
(i)
new
calculations
of
the
spatial
distribution
of
sulphate
aerosol
largely
resulting
from
fossil
fucl
combustion
and
[ii)
the
first
calculation
of
the
spatial
distribution
of
soot
aerosol.
The
impact
of
these
developments
on
the
calculation
of
aerosol
radiative
forcing
is
(!
iscussed
in
Section
B.
T.

..
..
.
..
.
..
­
.
..
.
concept
for
giving
a
first­
order
estimate
of
the
potential
climatic
importance
of
various
forcing
mechanisms.
However.
as
was
ernphasisecl
in
IPCC
(1994).
there
are
limits
to
its
utility.
In
particular.
the
spatial
patterns
of
forcing
differ
betneen
the
globally
well­
mised
greenhouse
gases.
rhe
regionally
var).
ing
tropospheric
ozone,
and
the
e
v
r
n
more
regionally
concentrated
tropospheric
aerosols.
and
so
a
comparison
of
the
global
mean
radiative
forcings
does
not
give
a
complete
picture
of
their
possible
climatic
impact.
Estimates
of
the
radiative
forcings
due
to
changes
in.
greenhouse
gas
concentrations
since
pre­
industrial
times
remain
unchanged
from
IPCC
(1994)
(see
Figure
2).
These
are
~2
.4
5
\V1i1­?
(range:
+2.1
ro
+2.8
Wm­
2)
for
the
direct
effect
of
the
main
w
l
l
­
mixed
greenhouse
gases
(CO.,,
CH,,
N,
O
ancl
the
halocarbqns),
i
O
.1
LV1n­
Z
(range:
0.2
to
0.
G
\I'm­
z)
for
tropospheric
ozone
and
­0.1
\Vm­
2
(range:
­0.05
to
­0.2
Wm­
2)
for
stratospheric
ozone.
­
The
total
direct
forcing,
due
to
anthvopogenic
aerosol
(sulphates,
fossil
fuel
..
soot
and
organic
aerosols
from
biomass
burning)
is
estimated
to
be
­0.5
Wm­
2
(range:
­0.25
to
­1.0
Wm­
2).
This
estimate
is
smaller
than
that
given
in
IPCC
(1994)
owing
to
a
reassessment
of
the
model
results
used
to
derive
the
geographic
distribution
of
aerosol
particles
ancl
the
inclusion
of
anthropogenic
soot
aerosol
for
tho
firsr
time.
The
direct
forcing
clue
to
sulphate
aerosols
resulting
from
fossil
fuel
emissions
and
smelting
is
estimated
to
be
­0.4
\Vm­?
(range:
­0.2
to
­0.8
\V
n
~­z
).
The
first
estimates
of
the
impact
of
soot
in
aerosols
from
fossil
fuel
sources
have
been
made:
significanr
uncertainty
re~
nains
but
an
estimate
of
+0.1
\Vm­?
(range;
0.03
to
0.3
Wm­
2)
is
made.
The
direct
radiative
forcing
since
1850
of
particles
associated
with
biomass
burning
is,
estimatcd
to
be
­0.2
\\
'm­
s
(range:
.­
0.07
to
­0.
G
LVm­
2).
unchanged
from
lPCC
(1994).
It
has
recently
been
suggested
that
a
significant
fraction
of
the
tropospheric
dust
aerosol
is
influenced
by
human
activities
but
the
racliati1.
e
forcing
of
this
component
has
not
yet
bee11
quantified.
.
I
ne
ran;
ic.
nf
w
r
i
r
l
l
z
t
x
for
rhc
rarliarl\.
c
fnrqc;
due
to
changes
in
cloud
properties
caused
by
aerosols
arising
from
human
activity
(the
indirect
effect)
is
unchanged
from
IPCC
(1994)
at
between
0
and
­1.5
IVm­
2.
Several
netv
studies
confirm
thnt
the
indirect
effect
of
aerosol
may
have
caused
a
substantial
negative
radiativc
forcing
since
pre­
­.
a
industrial
times,
but
it
remains
c'ery
difficult
to
direct
'warming"
and
indirect
"cooling"
effects,
quantify,
more
so
than
the
direct
effect.
While
no
have
now
been
estimated.
In'IPCC
(1994).
only
the
best
estimate
of
th;
indirect
forcing
can
currently
be
direct
GWPs
were
presented
for
these
gases.
The
made,
the
central
value
of
­0.8
Wm­
2
has
been
used
indirect
effect
reduces
their
GWPs,
but
each
ozone­
in
some
of
the
scenario
calculations
described
in
depleting
gas
must
be
considered
individually.
The
Sections
B.
9.2
and
F.
2.
net
CWPs
of
the
chlorofluorocarbons
(CFCs)
tend
to
There
are
no
significant
alterations
since
IPCC
be
positive.
while
those
of
the
halons
tend
to
be
(1994)
in
the
assessment
of
radiative
forcing
caused
negative.
The
calculation
of
indirect
effects
for
a
by
changes
in
solar
radiative
output
or
stratospheric
number
of
other
gases
(e.
g.,
NO,.
CO)
is
not
aerosol
loading
resulting
from
volcanic
eruptions.
currently
possible
because
of
inadequate
The
estimate
of
radiative
forcing
due
to
changes
in
characterisation
of
many
of
the
atmospheric
solar
radiative
output
since
1850
is
+0.3
W
m
­2
processes
involved.
(range:
+0.1
to
+0.5).
Radiative
forcing
due
to
Updates
or
new
GWPs
are
given
for
a
number
of
volcanic
aerosols
resulting
from
an
individual
key
species
(Table
41,
based
on
improved
or
new
eruption
can
be
large
(the
maximum
global
mean
estimates
of
atmospheric
lifetimes,
molecular
effect
from
the
eruption
of
&It.
Pinatubo
was
­3
to
­44
radiative
forcing
factors,
and
improved
'IVm­
2).
but
lasts
for
only
a
few
years.
However,
the
transient
variations
in
both
these
forcings
may
be
important
in
explaining
some
of
the
observed
climate
variations
on
decadal
time­
scales.

B.
8
Global
Warming
Potential
(GWP)
The
Global
Warming
Potential
is
an
attempt
to
provide
a
simple
measulre
of
the
relative
radiative
effects
of
the
emissions
of
various
greenhouse
gases.
The
index
is
defined
as
the
cumulative
radiative
forcing
between
the
present
and
some
chosen
tinie
horizon
caused
by
a
unit
mass
of
gas
emitted
now.
esprcssed
relative
to
thal:
for
some
reference
gas
(hcre
CO,
is
used).
The
future
global
warming
commitment
of
a
greenhouse
gas
over
a
chosen
tihe
horizon
can
be
estimated
by
multiplying
the
appropriate
GWP
by
the
amount
of
gas
emitted.
For.
example.
GWPs
could
be
used
to
compare
the
effects,
of
reductions
in
C02
emissions
relative
to
reductions
in
methane
emissions,
for
a
specified
time
horizon.
Derivation
of
GWPs
requires
knoyledge
of
the
fate
of
the
emitted
gas
and
the
radiative
forcing
due
to
the
amount
remaining
in
the
atmosphere.
Although
the
G'IVPs
are
quoted
as
single
values,
the
typical
uncertainty
is
+35%,
not
including
the
uncertainty
in
the
carbon
dioxide
reference.
Because
CWPs
are
based
on
the
radiative
forcing
concept,
they
are
difficult
t
o
a
p
p
l
y
t
o
r
a
d
i
a
t
i
v
e
l
y
i
m
p
o
r
t
a
n
t
constituents
that
are
unevenly
distributed
in
the
atmosphere.
No
attempt
is
made
to
define
a
GWP
for
aerosols.
Additionally
the
(choice
of
time
horizon
!vi11
depend
on
policy
considerations.
G'IVPs
need
to
take
account
of
any
indirect
effects
of
the
emitted
greenhouse
gas
if
they
are
to
reflect
correctly
future
warming
potential.
The
net
G\\
'Ps
for
the
ozone­
depleting
gases.
which
include
the
representation
of
the
carbon
cycle.
Revised
lifetimes
for
gases
destroyed
by
chemical
reactions
in
the
lower
atmosphere
(particularly
methane,
HCFCs
and
HFCs
)
have
resulted
in
GWPs
that
are
slightly
lower
(typically
by
10­
15%)
than
those
cited
in
IPCC
(1994).
The
IPCC
definition
of
GN'P
is
based
on
calculating
the
relative
radiative
impact
of
a
release
­
of
a
trace
gas
over
a
time
horizon
in
a
constant
background
atmosphere.
In
a
future
atmosphere
with
larger
CO,
concentrations,
such
as
occur
in
all
of
the
IPCC
emission
scenarios
(see
Figure
5b).
we
would
calculate
slightly
larger
CWP
values
than
those
given
in
Table
4.
'

9.9
Emissions
and
concentrations
of
greenhouse
gases
and
aerosols
in
the
future
5.9.
I
The
1592
emission
scenarios
The
projection
of
future
anthropogenic
climate
c
h
a
n
g
e
d
e
p
e
n
d
s
,
a
m
o
n
g
o
t
h
e
r
t
h
i
n
g
s
,'
o
n
­
assumptions
made
,about
future
emissions
of
greenhouse
gases
and
aerosol
precursors
and
the
proportion
of
e
m
i
s
s
i
o
n
s
r
e
m
a
i
n
i
n
g
i
n
t
h
e
atmosphere.
Here
we
consider
the
IS92
emission
scenarios
(IS92a
to
0
which
were
first
discussed
in
IPCC
(1992).
The
IS92
emission
scenarios
estend
to
the
year
2100
and
include
emissions
of
CO,.
CH,,
NzO,
the
halocarbons
(CFCs
and
their
substitute
HCFCs
and
HFCs).
precursors
of
tropospllerii
ozone
and
sulphate
aerosols
and
aerosols
from
biomass
burning.
A
wide
range
of
assumptions
regarding
future
economic,
demographic
and
policy
factors
are
encompassed
(IPCC.
1992).
In
this
report.
the
emissions
of
chlorine­
and
bromine­
containing
25
..

..
i
Table
4:
Global
Marming
Potential
referenced
to
the
updated
decay
response
for
the
Bern
carbon
cycle
model
ancljicture
CO,
atmospheric
concentrations
held
constant
at
current
levels.

S
p
e
c
i
e
s
C
h
e
m
i
c
a
l
GIobal
ll'arming
Potential
Formula
(Time
Horizon)
(years)
20
years
100
years
500
years
1
1
variables
co2
co2
1
hlethane*

Nitrous
oxide
CH4
N20
120
280
1223
56
21
6.5
3
1
0
1
7
0
­.

halocarbons
listed
in
IS92
a
r
e
a
s
s
u
m
e
d
t
o
b
e
phased
out
under
the
Montreal
Protocol
and
its
Adjustments
and
Amendments
and
so
a
single
*
revised
future
emission
scenario
for
these
gases
is
incorporated
in
all
of
the
IS92
scenarios.
,

Emissjons
of
individual
HFCs
are
based
on
the
original
IS92
scenarios,
although
they
do
not
reflect
current
markets.
C02
emissions
for
the
six
scenarios
are
shown
in
Figure
5a.
The
calculation
of
future
concentrations
of
greenhouse
gases,
given
certain
emissions,
entails
modelling
the
processes
that
transform
and
remove
the
different
gases
from
the
atmosphere.
For
example.
future
concentrations
of
COZ
are
calculated
using
models
of
the
carbon
cycle
which
model
the
exchanges
of
COz
b
e
t
w
e
e
n
.
t
h
e
a
t
m
o
s
p
h
e
r
e
a
n
d
t
h
e
o
c
e
a
n
s
a
n
d
t
e
r
r
e
s
t
r
i
a
l
biosphere
(see
Section
B.
1);
atmospheric
chemistry
models
are
used
to
simulate
the
removal
of
chemically
active
gases
such
as
methane.
All
the
IS92
emission
scenarios,
even
IS92c.
imply
increases
in
greenhouse
gas
concentrations
from
1990
to
2100
(e.
g.,
C02
increases
range
from
35
to
170%
(Figure
5b);
CH,
from
22
to
175%;
and
NzO
from
26
to
40%).

dependent
on
'the
concentration
of
the
gas
and
the.
strength
with
which
it
absorbs
and
re­
emits
long­
wave
radiation.
For
sulphate
aerosol,
the
direct
and
indirect
radiative
forcings
were
calculated
on
the
basis
of
sulphur
emissions
contained
in
the
IS92
scenarios.
The
radiative
forcing
due
to
aerosol
from
biomass
burning
was
assumed
to
remain
constant
a
t
­0.2
iVm­
2
after
1990.
The
contribution
from
aerosols
is
probably
the
most
uncertain
part
of
future
radiative
forcing.
Figure
6a
shows
a
single
"best
estimate"
of
historical
radiative
forcing
from
1765
to
1990
(including
the
effects
of
aerosols),
followed
by
radiative
forcing
for
Scenarios
,IS92
a
to
f.
Figures
6b
and
c
shoiv
the
contribution
to
future
radiative
forcing
from
various
components
of
the
'IS92a
Scenario;
the
largest
contribution
comes
from
COz,
with
a
radiative
forcing
of
almost
3­
6
Wm­
2
by
2100.
The
negative
forcing
due
to
tropospheric
aerosols,
in
a
globally
averaged
sense,
offsets
some
of
the
greenhouse
gas
positive
forcing.
Hotvever,
becaust.
tropospheric
aerosols
are
highly
variable
regionally,
their
globally
averaged
radiative
forcing
will
not
adequately
describe
their
possible
climatic
impact.
Future
projections
of
temperature
and
sea
level
b
a
s
e
d
o
n
t
h
e
I
S
9
2
e
m
i
s
s
i
o
n
s
s
c
e
n
a
r
i
o
s
a
r
e
discussed
in
Section
F.
.For
greenhouse
gases,
radiative
forcing
is
,

..

I
.

.­
IS92f
IS92a
IS92b
IS92d
IS92C
.
..
.
­
:2000
,2020
2040
2060
2080
2100
..
­
..
b
'
..
Year
­..."
'
,
.,
,

IS92e
IS92f
IS92a
IS92b
IS92d
IS92c
.*.3
0
0
[
'
'
'
'
'
'
I
'
'
'
1
.
.
.
,2000
:
2020
2040
2C60
2080
2100
..
..
.
'
.
..
..
.
.
.
,.

,
..
.
Year
[Figure
5:
(a)
Total
anthropogenic
CO,
emissions
under
the
IS92
emission
scenarios
and
(6)
the
resulting
atmospheric
,C02
concentrations
'calculated
using
the
'Bern'carbon
'cycle
model
and
the
carbon
budget
for
the
1980s
shown
in
Table
2.
.
...
.

..
..­.
.
.
..
..
.
..
...
.
..
.­

:;%­.:"
­
:'.
..
­
.
.
.
.

27
­.
..
8
Figure
6:
(a)
Total'globally
and
annually
averaged
historical
radiative
forcing
from
1765
to
1990
due
to
changes
in
greenhouse
gas
concentrations
and
tropospheric
aerosol
emissions
and
projected
radiative
forcing
ualues
to
2100
derived
from
the
IS92
emissions
scenarios.
(b)
Radiative
forcing
components
resulting
from
the
IS92a
emission
scenario
for
1990
to
2100.
The
'Total
non­
C02
trace
gases'
curue
includes
the
radiatiue
forcing
from
methane
(including
methane
related
increases
in
stratospheric
water
uapour).
nitrous
oxide.
tropospheric
ozone
and
the
halocarbons
(including
the
negative
forcing
effect
of
stratospheric
ozone
depletion).
Halocarbon
emissions
have
been
modged
to
take
account
of
the
Montreal
Protocol
nd
its
Adjustments
and
Amendments.
The
t
d
e
aerosol
components
are:
direct
sulphate,
indirect
sulphate
and
direct
biomass
burning.
(c)
Non­
C02
trace
gas
radiative
forcing
components.
'WBr
direct'
is
the
direct
radiative
forcing
resulting
from
the
chlorine
and
bromine
containing
halocarbons:
emissions
are
assumed
to
be
controlled
under
the
Montreal
Protocol
and
its
Adjustments
and
Amendments.
The
indirect
forcing
from
these
comp.
otrnds
(through
stratospheric
ozone
depletion)
is
shown
separately
(Stra;.
03.
All
other
emissions
follow
the
IS9Za
Scenario.
The
tropospheric
ozone
forcing
(Trop.
63
takes
account
of
concentration
changes
due
only
to
the
indirect
effect
of
methane.

2s
.
.

..
.
.­
..
Year
"
""
""
I­""

__"
""
"
"""
"
"
"
"
"
­
Sulphate
aerosol
­
indirect
­2
2000
2020
2,040
20602080.
2100
Year
l
.2
,b
l
l
l
l
l
l
l
I
I
Year
..
..

..
8.9.2
Stabilisation
of
greenhouse
gas
and
1000
4
aerosol
concentrations
950
(a)
'
e.
­
'­
SlijOO
i
/
/.

*
An
important
question
to
consider
is:
how
might
900
greenhouse
gas
concentrations
be
stabilised
in
the
850
;
future?
g
800
I
f
global
C02
emissions
were
maintained
at
near
'
g
750
;
current
(1994)
levels,
they
would
lead
to
a
nearly
3
700
;
c
o
n
s
t
a
n
t
r
a
t
e
of
i
n
c
r
e
a
s
e
i
n
a
t
m
o
s
p
h
e
r
i
c
5
650
:
S
650
.

concentrations
for
at
least
two
centuries.
reaching
2
6oo
:
about
500
ppmv
(approaching
twice
the
pre­
'
5j0
1
industrial
concentration
of
280
ppmv)
by
the
end
of
8
500
t
h
e
S
450.

In
IPCC
(19941,
carbon
cycle
models
were
used
to
calculate
the
emissions
of
C02
which
would
lead
to
stabilisation
of
different
concentration
Year
levels
from
350
to
750
ppmv.
The
assumed
concentration
profiles
leading
to
stabilisation
are
shown
in
Figure
i
a
(excluding
350
ppmv).
Many
different
stabilisation
levels,
.time­
scales
for
achieving
these
levels.
and
routes
to
stabilisation
could
have
b'een
chosen.
The
choices
made
are
not
intended
to
have
policy
implications:
the
exercise
is
illustrative
of
the
relationship
between
CO?
emissions
and
concentrations.
Those
in
Figure
7a
'
assume
a
smooth
transition
from
the
current
average
ratc
of
CO,
c
o
n
c
e
n
t
r
a
t
i
o
n
i
n
c
r
e
a
s
e
.
t9,
'
.
,
C02
emissions
stabilisation.
To
a
first
approsimntion.
the
stabiliscd
concentration
level
d
e
p
e
n
d
s
m
o
r
e
u
p
o
n
t
h
e
accumulated
amount
of
carbon
emitted
up
to
the
tirnc
of
s
t
a
b
i
l
i
s
a
t
i
o
n
,
t
h
a
n
u
p
o
n
t
h
e
e
x
a
c
t
c
o
n
c
e
n
t
r
a
t
i
o
n
p
a
t
h
followed
en
route
t
o
s
t
a
b
i
l
i
s
a
t
i
o
n
.
Year
­
/
/

/
/

­
/

v
/

.­

­

h:
ew
results
have
bcen
produced
to
take
account
of
the
revised.
carbon
budget
for
the
1980s.
(Table
21,
b,
ut
the
main
conclusion,
that
stabilisation
of
concentration
requires
emissions
eventually
to
drop
well
below
current
levels,
remains
unchanged
from
IPCC
(1994)
(Figure
ibl.
Because
the
new
budgct
implies
a
reduced
terrestrial
sink.
the
allowable
emissions
to
achieve
stabilisation
are
up
to
10%
lower
than
those
in
IPCC
(2994).
In
addition,
these
calculations
have
been
estended
to
include
alternative
pathways
towards
stabilisation
(Figure
7a)
and
a
higher
stabilisation
level
(1000
ppmv).
The
alternative
pathways
assume
higher
emissions
in
the
early
years,
but
require
steeper
reductions
in
en1ission.
i
i
i
1
latcr
years
(Figure
7bl.
The
1000
ppxn;
stabilisation
case
allows
higher
maximum
emissions,
but
still
requires
a
decline
to.
current
levels
by
about
2­
10
years
from
now
and
further
reductions
thereafter
(Figure
7b).
Figure'
7:
(a)
CO,
concentration
profiles
leading
to
stlnbilisation
at
450.
550.
650
and
750
ppmc
following
the
pathways
defined
in
IPCC
(1994)
(solid
curtes)
and
for
.
pathways
that
allow
emissions
to
follow
IS92a
until
at
least
2000
(dashed
curves).
A
single
profile
that
stabilises
at
a
CO,
concentration
of
1000
ppmv
and
follow
IS92a
emissions
until
at'least
2000
has
also
been
defined.
(b)
C02
emissions
leading
to
stabilisation
at
concentrations
of
450.
550,
650,
750
and
1000
ppmv
following
the
profiles
shown
in
(a).
Current
anthropogenic
CO,
emissions
and
those
for
IS92a
are
shown
for
comparison.
The
calculations
use
the
­Bern'
carbon
cycle
model
and
the
carbon
budget
for
the
7980s
shown
in
Table
2.

..
.

29
halocarbons
listed
in
IS92
are
assumed
t
o
b
e
phased
out
under
the
Montreal
Protocol
and
its
4
Adjustments
and
"hendrnents
and
so
a
single
revised
future
emission
scenario
for
these
gases
is
incorporated
in
all
ot'the
IS92
scenarios.
Emissiors
of
individual
HFCs
are
based
on
the
original
1592
scenarios,
although
they
do
not
reflect
current
merkets.
CO,
emissions
for
the
six
scenarios
a
r
e
shoivn
in
Figure
5a.
The
calculation
of
future
calncentrations
of
greenhousd
ga.
ses.
given
certain
emissions,
entails
m
o
d
e
h
g
the
processes
that
transrorm
and
remove
the
d.
ifferent
gases
from
the
atmosphere.
For
example,
future
concentrations
of
COP
a
r
e
calculared
using
models
of
the
carbon
cycle
which
model
the
exchanges
of
CO?
b
e
t
v
i
e
e
n
t
h
e
a
t
m
o
s
p
h
e
r
e
a
n
d
t
h
e
o
c
e
a
n
s
a
n
d
t
e
r
r
e
s
,t
r
i
a
l
biosphere
(see
Section
B.
1);
atmospheric
chemistry
m
o
d
e
l
s
a
r
e
u
s
e
d
to
simulate
the
remova.
1
of
chemically
active
gases
such
as
methane.
All
the
IS92
emission
scenarios.
even
IS92c.
imply
increases
in
greenhouse
gas
concentrations
from
1990
to
3100
(e
g
.
C02
increases
range
from
35
to
170%
(Figure
5b);
CII,
from
22
to
175%;
and
N20
from
26
to
­10%).

dependent
on
the
Concentration
of
the
gas
and
tiii
strength
ivith
which
it
absorbs
and
re­
emits
long­
wave
radiation..
For
sulphate
aerosol.
the
direct
and
indirect
radiative
forcings
were
c;
alculated
on
th.
e
basis
of
sulphur
emissions
contained
in
ithe
IS92
scenarios.
The
radiative
forcing
due
to
aerosol
from
biomass
burning
was
assumed
to
remain
constant
a
t
­0.2
Zvmn­*
after
1990.
The
cantribulion
from
aerosois
is
probably
the
most
uncertain
part
of
future
radiatiwe
forcing.
Figure
Ga
shows
a
single
"best
estimate"
of
historical
radiative
forcing
from
1765
to
1990
(including
,the
effects
of
aerosols).
folllavcved
by
radiative
forcing
for
Scenarios
IS912
a
to
1.
Figures
6b
anld
c
show
the
Contribution
to
future
radiative
forcing
from
variow
components
of.
the
IS92a
Scenario;
the
largest
contribution
comes
from
C02,
with
a
radiative
forcing
of
almost
+15
Wm­
2
!by
2100.
The
negative
forcing
due
to
tropospheric
aerosols,
ir.
R
z1?
5?.!!
y
everF.
yd
serse.
n
f
f
w
t
y
snmp
of
t
h
~
greenhouse
gas
positive
forcing.
However,
because
tropospheric
aerosols
are
highly
veriable
regionally,
their
glo5ally
averaged
radiative
forcing
will
not
adequetely
describe
their
possible
climatic
impact.
Future
projections
of
temperature
and
sea
level
based
on
the
IS92
emissions
scenarios
are
discussed
in
Section
F.
For
greenhouse
gases.
radiative
forcing
is
'
4
0
,,,,,,,,,,

lS92t
IS92a
IS92b
IS92d
IS92C
.­.
.
2000
,
2020
2040
2060
2080
2100
t
':
..
d.
Year
..
­.
..
.
.­
.
..
.­
.
IS92e
IS92f
..
2000
2020
2040
2060
2080
2100
..
..
.
.
..
Year
Figure
5:
(a]
Taltal
anthropogenic
CO,
emissions
under
the
­15912
emission
scenarios
and
(a)
the
resulting
atmospheric
GO2
concentrlutio­
ns
calculated
using
the
'Bern'
carbon
'
cycle
model
hnd
the
carbon
budget
for
the
1980s
shown
in
Table
2.
..
.
.
.
,.
_­
­
­
3
."
x,,.::
.
.
..
.^
.
..
.
..
B.
6
Tropospheric
and
stratospheric
aerosols
­
Aerosol
is
a
term
used
for
particles
and
very
Small
droplets
of
natural
and
human
origin
that
occur
in
the
atmosphere;
they
include
dust
and
other
particlcs
which
can
be
made
up
of
many
different
chemicals.
Aerosols
are
produced
by
a
variety
of
processes.
both
natural
(including
dust
storms
and
volcanic
activity)
and
anthropogenic
(including
fossil
fuel
and
biomass
burning).
Aerosols
contribute
to
visible
haze
and
can
cause
a
diminution
of
the
intensity
of
sunlight
at
the
ground.
.4erosols
in
the
atmosphere
influence
the
radiation
balance
of
the
Earth
in
two
ways:
(i)
by
scattering
and
absorbing
radiation
­
the
direct
e
p
c
t
,
and'(
ii1
by
modifying
the
optical
properties,
amount
and
lifetime
of
clouds
­
the
irdirrct
effect.
.Uthough
some
aerosols..
such
as
soot,
tend
to
warm
the
surface.
the
net
clinmtic
effect
of
anthropogetlic
aerosols
is
belicved
to
be
a
negative
radiativc
forcing.
tending
to
cool
the
surface
(see
Sectidn
B.
7
and
Figure
21.
Most
aerosols
tvith
anthropogenic
sources
are
found
in
the
lower
troposphcrc
(below
2
km).
A
e
r
o
s
o
l
s
i
n
d
e
r
g
o
c
h
e
r
n
i
c
a
l
a
n
d
p
h
y
s
i
c
a
l
transformations
in
the
atmosphcre:
cspecially
within
clouds.
and'are
removed
largriy
by
prccipitation.
Consoqucntly
aerosols
in
the
lower
troposphcrc
typically
have
rcsidcncc
times
of
a
few
days.
Bccausc
of
thcir
short
lifetime.
aerosols
in
thc
lowdr
troposphcrc
are
distributrd
inhomogcncously
ivith
maxima
closc
to
the
natural
(especiaiiy
desert)
and
anthropogenic
(cspccinlly
industrial
and
biomass
combustion)
source
regions.
Aerosol
particlcs
resulting
from
volcanic
activity
.can
reach
thc
.
stratosphrrc
where
they
are
transportrd
around
thc
globc
over
many
months
or
years.
The
radiative
forcing
due
to
aerosols
depends
on
the
size.
shapc
and
chcmical
composition
of
thc
particles
and
the
spatial
distribution
of
the
aerosol.
LVhile
thcsc
factors
are
comparatively
well­
knoun
for
'
stratospheric
aerosols,
there
remain
many
uncertainties
concerning
trop&
pIleric
aerosols.
Since
IPCC
(1994).
there
have
been
scveral
a
d
v
a
n
c
c
s
i
n
u
n
d
e
r
s
t
a
n
d
i
n
g
t
h
e
i
m
p
a
c
t
of
'tropospheric
aerosols
on
clim5te.
These
include:
li)
new
calculations
of
the
spatial
distribution
of
sulphnx
neroso!
Inr221y
resulting
from
fossil
fud
combustion
and
(ii)
the
first
calculation
of
the
spatial
distributiop
of
soot
aerosol.
The
impact
of
thcse
developmcnts
on
the
calculation
of
aerosol
radiative
forcing
is
discussed
in
Section
f3.7.

..

'4
..
..
..
.
..
­
..
,
B.
7
Summary
of
radiative
forcing
Globally
averaged
radiative
forcing
is
a
useful
concept
for
giving
a
first­
order
estimate
of
the
potential
climatic
importance
pf
various
forcing
mechanisms.
However.
as
was
emphasised
in
IPCC
(1994),
there
are
limits
to
its
utility.
In
particular.
:he
spatial
patterns
of
forcing
differ
betiyeen
the
globally
tvell­
mixed
greenhouse
gases,
the
regionally
\wying
tropospheric
ozone,
and
the
even
more
regionally
concentrated
tropospheric
aerosols.
and
so
a
comparison
of
the
global
mean
radiative
forcings
docs
not
give
a
complete
picture
of
their
possible
elinlatic
impact.
Estimates
of
the
radiative
forcings
due
to
changes
in
greenhouse
gas
concentrations
since
pre­
industrial
times
remain
unchanged
from
IPCC.
(19341
(see
Figure
2).
These
are
+2.45
W
m
­2
(range:
t2.1
to
+2.8
iVm­
2)
for
the
direct
effect
of
the
main
\veli­
mixed
greenhouse
gases
(C02.
CH+
N20
and
the
halocarbonsj.
+0.4
Ct'm­
2
(range:
0.2
to
0.6
V
h
­2
)
for
tropospheric
ozone
and
­0.1
iVm­
2
(range:
­0.03
to
.

­0.2
Wm­
2)
for
stratospheric
ozone.
The
total
direct
forcing
due
to
anthropogenic
aerosol
(sulphatcs,
fossil
fuel
soot
and
organic
aerosols
From
biomass
burning)
is
estimated
to
be
­0.5
iVm­
2
(range:
­0.25
to
­1.0
iVm­
2).
This
estimate
is
smallcr
than
that
givenjn
IPCC
(1994)­
owing
to
a
reasscssnlent
of
the
model
results
used
to
derive
the
geographic
distribution
of
aerosol
particles
and
the
inclusion
of
anthropogenic
soot
aerosol
for
the
first
time.
Thc
direct
forcing
due
to
sulphate
aerosols
rcsulting
from
fossil
fuel
emissions
and
smelting
is
estimated
10
be
­0.4
CVm­
2
(range:
­0.2
to
­0.8
tvnr').
The
first
estimates
0.
f
the
impact
of
soot
in
aerosols
from
fossil
fuel
sources
have
been
made:
significant
uncertainty
rcmains
but
an
estimate
of
+0.1
C
t
'
m
­~
(range:
0.03
to
0.3
iVm­
2)
is
made.
The
direct
radiative
forc'ing
since
1850
of
particles
associated
with
,biomass
burning
is
estimated
to
be
­0.2
LVm­
2
(range:
­0.07
to
­0.
G
\.
'dm­
21.
unchanged
from
IPCC
(1994).
I
t
has
recently'
been
suggested
that
a
significant
fraction
of
the
tropospheric
dust
aerosol
is
influeked
by
human
activities
but
the
radiative
forcing
of
this
component
has
not
yet
been
quantified.
Tho
rerlyr
nf
v
+t
T
r
t
w
fnr
thn
rac!
i?.!
i.­
r
fc:~!:::
due
to
changes
in
cloud
properties
­caused
b).
aerusois
arising
from
human
acrivitj­
(tho
indirccr
effect)
is
unchanged
from
IPCC
(1994)
at
between
0
and
­1.5
!Ym­?.
Several
new
studies
confirm
that,
the
indirect
effect
of
aerosol
tnai
have
caused
2
substantial
negative
radiative
forcing
since
pre­
­

..

..
.
..
..
..
.

'
,­
..
..
..
.
.
..
..
,"
~
I
direct
'warming"
and
indirect
"cdoling"
effects.
have
now
been
estimated.
In
IPCC
(1994),
only
the
direct
GLYPs
were
presented
for
these
gases.
The
indirect
effect
reduces
their
GLVPs,
but
each
ozone­
dep!
eting
gas
must
be
considered
indiridually.
The
net
G\
VPs
of
the
chlorofluorocarbons
(CFCs)
tend
to
be
positive.
while
those
of
the
halons
tend
to
be
negative.
The
calculation
of
indirect
effects
for
a
number
of
other
gases
(e.
g..
NO,.
CO)
is
not
currpntly
possible
because
of
inadequate
characterisation
of
many
of
the
atmospheric
processes
involved.
Updates
or
new
CWPs
are
given
for
a
number
of
key
species
(Table
4).
based
on
improved
or
new
estimates
of
atmospheric
lifetimes,
molecular
~a
d
i
a
t
i
v
e
'
f
o
r
c
i
n
g
f
a
c
t
o
r
s
,
a
n
d
i
m
p
r
o
v
e
d
representation
of
the
carb'on
cycle.
Revised
lifetimes
for
gases
destroyed
by
chemical
reactions
in
the
lon.
er
atmosphere
(particularly
methane,
HCFCs
and
HFCs
)
have
resulted
in
GWPs
that
are
slightly
lolver
(typically
by
10­
15%/
0)
than
those
cited
in
IPCC
(1994).
The'
IPCC
definition
of
GWP
is
based
on
calculating
the
relative
radiative
impact
of
a
release
of
a
trace
gas
over
a
time
horizon
in
a
constant
background
atmosphere.
In
a
future
atmosphere
with
larger
COz
concentrations.
such
as
occur
in
all
.

of
the
IPCC
emission
scenarios
(see
Figure
5b),
we
\vould
calculate
slightly
larger
GWP
values
than
,

those
given
in
Table
4.
­

o!
J
Emissions
and
concentrations
of
reenhouse
gases
and
aerosols
in
the
future
B.
9.
I
The
IS92
emissr"
on.
scenarios
.
'

The
projection
of,
future
anthropogenic
climate
change
depends.
among
other
things.
on
assumptions
made
about
future
emissions
of
greenhouse
gases
and
aerosol
precursors
and
the
proportion
of
e
m
i
s
s
i
o
n
s
r
e
m
a
i
n
i
n
g
i
n
t
h
e
atmosphere.
Here
we
consider
the
IS92
emission
scenarios'(
IS92a
to
0
which
were
first
discussed
in
­

IPCC
(1992).
The
IS92
emission
scenarios
extend
to
the
year
2100
and
include
emissions
o
f
C02,
CH,,
N,
O,
the
halorarhons
KFCs
and
their
sz~
hstitute
HCFCs
and
HFCsl.
precursors
of
tropo,
spheric
ozone
and
a.
2>
lLL.:
c
aerosols
and
aerosols
fro:,
biomass
burning.
A
wide
range
of
assumptions
regaiding
dutijre
economic,
demographic
and
policy
factors
;!
re
encompassed
(IPCC.
1992).
In
this
report,
the
emissions
of
chlorine­
and
!bromine­
containing
23
..
..
,.
,
..
..
.
..
..
>­
..
..
,"

Global
average
methane
concentrations
increased
by
6%
over
the
decade
starting
in
1984
(Figure
3).
Its
concentration
in
199­
1
was
about
1720
ppbv,

­
14504
greater
than
the
pre­
industrial
concentration
of
700
ppbv
(Table
1,
Figure
3).
Over
the
last
20
years,
there
has
been
a
decline
in
tlie
methane
gronrh
rate:
in
the
late
1970s
the
concentration
was
increasing
by­
about
20
ppbvlyr,
during
the
1980s
the
groivth
rate
dropped
to
9­
13
ppb::/
yr.
Around
the
middle
of
1992,
merhane
concentrations
briefly
stopped
growing.
but
since
1993
the
global
growth
rate
has
returned
to
about
8
ppbvlyr.
I
n
d
i
v
i
d
u
a
l
m
e
t
h
a
n
e
s
o
u
r
c
e
s
a
r
e
n
o
t
w
e
l
l
quantified.
Carbon
isotope
measurements
indicate
t
h
a
t
a
b
o
u
t
20%
of
the
total
annual
methane
emissions
are
related
to
the
production
and
use
of
foskil
fuel.
In
total.
anthropogdic
activities
are
responsible
for
about
6040%
of
current
methane
emissions
(Table
3).
Nethane
emissions
from
natural
wetlands
appear
to
contribute
about
20%
to
the
gtobal
methane
emissions
to
the
atmosphere.
Such
emissions
will
probably
increase
with
global
warming
as
a
result
of
greater
microbial
activity.
In
1932
the
direct
radiative
forcing
due
to
the
increase
in
methane
concentration
since
pre­
industrial
times
was
about
+0.47
Wm­­
(Figure
2).
Changes
in
the
concentratim
of
methane
have
clearly
identified
che~
nical
feedbacks.
The
main
removal
process
for
methane
is
reaction
with
the
hydroxyl
radical
(OIH).
.Addition
of
methane
to
the
atmosphere
reduces
the
.
Concentration
of
tropospheric
Oll
which
can
in
turn
feed
back
and
roduco
the
rate
of
methane
removal.
The
adjustment
time
for
a
pulse
of
methane
added
.,
to
the
atmosphere
has
been
revised
to
12
(+
3)
years
(compared
with
14.5
(c2.5)
years
in
IPCC
(1991)).

.
Two
factors
are
responsible
fof
the
change:
(a)
a
new
estimate
for
the
chemical
removal
rate
(11%
faster);
and
(b)
inclusion
of
the
uptake
of
methane
by
soils.
The
revised
global
sink
strength
is
560
(*
loo)
Tg(
CH$/
year,
higher
than
the
1991
estimate,
but
still
consistent
with
the
previous
range
of
global
.
source
strength.

B.
3
Nitrous
oxide
(N,
O)
There
are
many
small
sources
of
nitrous
oxide,
'
.
both
nntrlra!
and
zc:!;
r2p;;::::;,
;;
i1iiil
arc
jiiiicult
to
quantify.
The
main'
anthropogenic.
so.
ilrces
are
fruit1
agricuirure
and
a
number
of
industrial
processes'
(e.
g..
adipic
acid
and
nitric
acid
productionl.
'4
best
estimate
of
the
current
(1980s)
anthropogenic
emission
of
nitrous
oxide
is
3
to
8
/.

...
..
.
,.
22
i
.I
..
..
..

.
.I
..
­
..

".
.
.
­.
.
_..
.

,
I:
.
1.
.­
,
..
I
..
Tg(
N)/
yr.
Natural
sources
are
poorly
q
1
.1
,~r
r
i
f
i
p
c
l
~
bur
are
probably
twice
as
large
as
allthropoge;
lic
sources.
Nitrous
oxide
is
removed
n;
alnl!,
by
photolysis
(breakdowx
by
sunlight)
in
the
stratqsphere
and
conseyuer.
d~
has
a
ion;
lifetirr:?
(about
120
years).
Although
sources
cannot
be
well
cjr.
antiEet\,
atmospheric
measurements
and
evidencc
from
ice
cores
shoiv
that
the
atmospheric
abunciance
of
nitrous
oside
has
incroased
since
the
pre­
inciustrial
era,
most
likely
otving
to
human
activities.
In
199:
armospheric
levels
of
nitrous
oxide
were
abour
312
ppbv:
pre­
industrial
levcls
\rere
about
275
ppbv
(Table
1).
The
1993
grow.
th
rate
Eapprosimarely
0.5
ppbvlyr)
was
lower
than
that
observed
in
the
late
1980s
and
early
1990s
(approximately
0.5
pphI,/
yr).
but
these
short­
term
changes
i
n
gronth
rate
are
within
the
range
of
variabilig.
seen
on
decadal
time­
scates.
The
radiatir.
e
forcing
due
t
o
thc
chnnge
in
nitrous
oxide
since
pre­
industrial
times
is
about
1­
0.14
1Vm.
Z
(Figure
2).

B.
4
Halocarbons
and
other
­

halogenated
campounds
Halocarbons
are
carbon
compounds
conraining
fluorine.
chlorine.
bromine
or
iodine..
Many
of
these
are
efrective
greenhouse
gases.
For:
most
of
these
cdrnpounds.
human
activities
am
the
sole
source.
Halocarbons
that
contain
chlarinc
(CFCs
ancl
HCFCs)
and
bromine
(hnlonsd
I::
BLIS@
ozone
depletion,
and
thcir
e~
nissions
are
contrullcci
under
the
Montreal
Protocol
and
its
Adjustments
and
Amendrncnts.
As
a
result.
growth!
ratcs
i
n
the
conccncraeirjns
of
many
of
these
compounds
have
already
fallen
(Fig&
4)
and
tPlc
radiative
impact
of
these
compounds
w
i
l
l
slowly
decline
oyer
the
nest
century.
The
contribution
to
dirccl
radinti1.
e
forcing
due
to
Concentration
increases
of
these
CFCs
and
HCFCs
since
pre­
industrial
timcs
is
itbout
+0.25
\l'm­?.
Halocarbons
can
also
exert
an
indirect
negative
radiative
forcing
through
their
depletion
of
stratospheric
ozone
(see
Section
R.
5.2).
Perfluorocarbons
(PFCs.
e.
g..
CF,,
C2F6)
and
sulphur
­hexafluoride
iSF6)
are
removed
very
slo\
vly
from
the
atmosphere
\\
lth
estimated
lifetimes
greater
than
1000
years.
As
a
result,
dh­
hv>
l!:
?1'
P
Y
!::::
::
accumulate
in
the
atmosphere
and
will
continue
to
influrnre
rlirnntc
fo~
r
thsis:
tdz
uljears.
Although
the
radiative
forcing
due
to
concentration
increases
of
these
compounds
since
pre­
industrial
times
is
sn?
all
(about
­1.0.01
IVtn.
').
it
may
b
e
r
m
e
significant
in
the
future
if
concentrations
continste
to
increase.
HydrofZuororarbons
IIHFCS)
;­!
Ye
being
used
?I
)

replace
ozone­
deplehg
substances
in
some
applications;
rheir­
concentI
ations
and
radiative
impacts
are
currently
small
I
f
emiss:
ons
increase
as
envisaged
in
Scenario
IS92a,
the!
5r.
ould
contributc
about
3%
of
the
tora.
1
radiati\,
e
forcing
from
all
greenhouse
ga'es
bq.
the
year
2
11.)
5.

­9.5
Ozone
(0,)
Ozone
is
an
.;::
portan:
grccnho,~
l;
e
gas
pslescnt
i!
l
both
the
stratosphere
and
troposphere.
Changes
in
ozone
ca::
se
rndintit
2
forciw:
b)
influencing
both
solar
anti
terrestrial
radiation.
The
net
radiative
forcing
is
strongi)
dependent
on
the
vertical
distriburicn
of
ozone
chang
­
and
is
panticularli.
sensitive
to
cI:
anges
around
the
tropopause
levell,
where
trends
are
diriit:
tdt
to
estimate
due
to
a
18ack
01'

reliable
observations
2nd
tho
\:
xry
large
,
natural
variability
ThcL
patterns
o
f
both
troposphcric
anti
stratospheric
ozone
changes
are
spatially
variable.
Estimation
of
t!
le
radi#:
ltive
forcing
d
u
~
to
changes
in
ozone
is
thus
more
comples
than
for
the
well­
mixed
greenhouse
gases.

8.5.
I
Tropcspheric
Ozone
In
the
troposphcrc.
ozone
is
produced
during
the
I
oxidation
of
tfxthnnc
and
from
vnri'ous
st­
lort­
livcdw
precursor
gases
(mainly
c;
srbon
monoxide
(CO),
nitrogen
oxides
CNQ,)
and
non­
nlcthane
hydrocarbons
(NMIiC1).
Ozone
is
a.
lso
transported
into
the
troposphcre
from
the
stratosphrrc
IChangcs
in
,troposphc~­
ic
ozonc
conccntratilJru,
are
spatially
variable,
both
regiocnlly
and
rsticall,:
matking
assessment
of
global
ilnr1q­
term
trends
difficult.
I
n
the
Northern
iiemisphere.
there
is
some
evidence
that
tropospheric
ozone
concentrat~
t~
nS
have
increascd
since
1900,
with
str1on;
g
widcnlcc
that
Ih'k
has
13ccurrcd
in
many
locations
sino:
the
19GOs.
However,
the
obsen?
ations
of
h
e
most
recent
dccade
stlow
that
the
upward
trl:>
nd
has
SIO!
AWI
significantly
or
stopped.
Model
simulations
and
the
limited
observations
together
suggest
tha.
t
ozone
conccntrmntions
thrloughout
the
troposphere
may
have
douhicc!
in
the
Piortlhern
Hemisphcrr:,
since
pre­
industrial
times,
an
increase
of
about
25
ppbv.
In
the
Southern
Hemisphere,
therc!
are
insuffcient
ldata
to
determine
if
tropospheric
0ron.
e
has
has
been
objervi:
d
sincc
the
mid­
1
9::
Os.
Likiigcd,
e.
'\~
t.
pi
<.;
LlL
dLluiil
i
c,;
u
.+
iit.
lc
~~c
:~~~l
~~~,.j
t
.

Changes
in
tropospheric
ozone
hake
potentially
important
~cOnsfquence.;
for
radiative
fcrcirrg.
The
calculated
giobal
averq?
radiati­.
tt
Iurcing
dule
to
the
increased
cnncer?.
tratioil
since
pre­
industrial
1:
imes
is
+0.4
(50.2)
SVm­
2.

..

­.
.
Year
',
li
Figure
4:
Global
CFC­
I1
concentrations
(pptcr.
ifar
1978
to
1994.
As
one
ofthe
ozone­
depletinggases.
rhc
emissiohs
of
CFC­
I1
are'
conrrolled
under
the
Aforzrrecl!
Protocol
and
its
Adjustments
and
Amendrnerlts.
Observations
at
some
individual
measurement
sites
are
also
shown!.

.
8.5.2
Stratiospheric
Ozone
Decreases
in
stratosphcric
ozone
haw
occurred
since
the
14170s.
principally
in
the
iowt:
r
stratosphere.
The
most
ob7;
ious
featurc
i
s
t
h
e
annual
appcarnnce
of
thc
Antarctic
"ozonc
hole"
in
Scptonibcr
and
Octobw.
The
October
average
totill
w
o
n
0
values
elver
Antarctica
are
50­
70%
IOWCI.
t
h
a
n
those
observed
in
the
1960s.
Statistically
siznificant
losses
in
tomtni
ozone
have
also
been
observed
in
the
mi$­
latitudes
of
both
hemispheres,
Little
01­
n'ca
dorvnw,
ard
trcnd
in
ozone
has
beet?
observeld
in
the
tropics
(2QPN­
20"
S).
The
iveight
08f
recent
scientific
evidence
strengthens
thr
pre~
ious
conclusion
that
ozonle
loss
is
due
lacgely
to
anthroplogenic
chlorine
and
bromine
compounds.
.

S
i
l
:c
e
the
stratospheric
ahundances
of
chlorine
and
bromine
arb
expected
to
continue
to
grot$­
for
a
reit;
more
years
before
they
decline
(see
Section
B.
41,
s,
rrntosplheric
ozone
losses
are
expected
to
peak
near
t
h
f
end
of
the
century,
with
a
gradual
recover)
r
L!
.
.1
.,..
.x..
~
,."
t,..
,ddi.
vk.
u
>.L
:.
'aL
!iu;
T
u.
'
?i>
L
CGLLL;,.

­The
loss
of
ozone
in
tho
loiver
StratosptlPre
over
'

the
past
1:
s
to
20
years
has
led
to
a
globallJr
a:
cragecl
radiative
forcing
of
about
­0.1
\Vn1.2.
This
nepntive
radiative
famin::
represents
an
indirect
effr.
ct
o
f
anthropogcqic
chlorine
and
brom!
ne
coxpounds:

..
..
..
.,
,\
1
..
..
..
..
..
B.
6
Tropospheric
and
stratospheric
aerosols
­
Aerosol
is
a
term
used
for
particles
and
very
small
droplets.
of
natural
and
human
origin
that
occur
in
the
atmosphere;
they
include
dust
and
other
particles
which
can
be
made
up
of
many
clifferent
chemicals.
Aerosols
are
produced
by
a
variety
of
processes,
both
natural
(including
dust
storms
and
volcanic
actiLVity)
and
anthropogenic
(including
fossil
fuel
and
biomass
burning).
Aerosols
contribute
to
visible
haze
and
can
cause
a
diminution
of
the
intensity
of
sunlight
at
rhe
ground.
Aerosols
in
the
atmosphere
influence
the
radiation
balance
of
the
Earth
in
two
ways:
(i)
by
scattering
and
absorbing
radiation
­
the
dfrect
effect,
and
(ii)
by
modifying
the
optical
propertds.
amount
and
lifetinle
of
clouds
­
the
irrdircct
effect.
Although
some
aerosols.
such
a
s
soot,
tend
to
warm
the
surface,
the
net
climatic
effect
of
anthropogenic
aerosols
is
believed
to
be
a
negative
radiative
forcing,
tending
to
cool
the
surface
(see
Section
13.7
and
Figure
2).
Most
aerosols
with
anthropogenic
sources
are
found
in
thc
lower
troposphere
(bclotv
2
km).
Aerosols
u
n
c
l
c
r
g
o
c
h
e
m
i
c
a
l
a
n
d
p
h
y
s
i
c
a
l
transformations
in
the
atmosphcp.
especially
within
clouds,
and
are
removed
largcly
by
precipitation.
Conscqucntly
acrosols
in
thc
loivcr
troposphere
typically
have
resiclcncc
times
o
r
a
f
c
k
days.
Bccausc.
of
thcir
short
lifctimc.
aerosols
in
the
lower
troposphere
nr!
distributcd
inhomogcncorrsi~
with
masinla
close
to
the
natural
(especially
desert)
.and
anthropogenic
(especially
industrial
and
biomass
combustion)
source
regions.
Aerosol
particles
resulting
from
volcanic
activity
can
reach
the
stratosphcre
where
they
are
transported
around
the
globe
over
many
months
or
years.
.
'

The
radiative
forcing
due
to
aerosols
depcnds
on
the
size.
shape
and
chemical
composition
of
the
particlcs
and
the
spatial
distribution
of
the
aerosol.

.
\iVllilc
'these
factors
are
comparatively
well­
known
for
stratospheric
aerosols,
there
remain
many
uncertainties
concerning
tropospheric
aerosols.
Since
IPCC
(1994).
there
have
been
several
a
d
v
a
n
c
e
s
i
n
u
n
d
e
r
s
t
a
n
d
i
n
g
t
h
e
i
m
p
a
c
t
o
f
tropospheric
aerosols
on
cliinate.
These
include:
(i)

sulphate
aerosol
largely
resulting
from
fossil
f
w
l
combustion
and
(ii)
the
first
calculation
of
the
spatial
distribution
of
soot
aerosol.
The
.impact
of
these
developments
on
the
calculation
of
aerosol
radiative
forcing
is
discussed
in
Section
13.;.
..

II":
'.
'
C:.!:
L!
s:":
5
"T
Li,
C
5prliidl
u
l
~l
r
l
u
u
r
i
u
l
l
~
u
i
24
9.7
Summary
of
radiative
forcing
Globally
averaged
radiative
forcing
is
a
usefill
concept
for
giving
a
first­
order
estimate
of
the
potential
climatic
importance
of
various
forcing
mechanisms.
Hojvever,
as
was
emphasised
in
IPCC
(199111,
there
are
limits
to
its
utility.
In
particular.
the
spatial
patterns
of
forcing
differ
betireen
the
globally
well­
mised
greenhouse
gases,
the
regionally
varying
tropospheric
ozone,
and
the
even
more
regionally
concentrated
tropospheric
aerosols.
and
so
a
comparison
of
the
global
mean
radiative
forcings
does
EO:
give
a
complete
picture
of
their
possible
cliniatic
impact.
Estimates
of
the
radiative
forcings
due
to
changes
in
greenhouse
gas
concentrations
since
pre­
'industrial
tinles
remain
unchanged
from
IPCC
(19.94)
(see
Figure
2).
These
are
+2.45
it.
111­
2
(range:
+2.1
to
+2.8
Wm­
2)
for
the
direct
effectof
thc
main
well­
rnised
grcenhouse
gases
(CO,.
CH,,
K20
and
the
halocarbons),
+0.4
IVm­
2
(range:
0.2
to
0.
G
\V
d
)
for
tropospheric
ozone
and
­0.1
iVm­
2
(range:
­0.05
to
­0.2
VVm­
2)
for
stratospheric
ozone.
The
total
direct
forcing
due
to
anthropogenic
aerosol
(sulphates.
fossil
fuel
soot
and
organic
aerosols
from
biomass
burning)
is
cstimated
to
be
­0.5
iVm­
2
(range:
­0.25
to
­1.0
IYm­
2).
This
estimate
is
smaller
than
that
given
in
IPCC
(1994)
oLving
to
a
reassessment
of
the
model
results
used
to
dcrivc
the
geographic
distribution
of
aerosol
particlcs
and
the
inclusion
of
anthropogenic
soot
aerosol
for
the
first
time.
Thc
dirrtcr
forcing
due
to
sulphate
aerosols
resulting
from
fossil
fuel
emissions
and
smelting
is
.
estimated
to
be
­0.4
\l'm­
z
(range:
­0.2
to
­0.
S
LVm.
').
Thc'first
cstimates
of
the
impact
of
soot
in
aerosols
from
fossil
fuel
sources
have
bccn
made:
significant
uncertainty
remains
but
an
estimate
of
+0.1
\t'm­
z
(range:
0.03
to
0.3
Wm­
2)
is
made.
The
direct
,

.radiative
forcing
since
1850
of
particles
associated
with
biomass
burning
is
estimatdd
to
be
­0.2
\Vm­
n
(range:
­0.07
to
­O
h
IVrn­
2).
unchanged
from
IPCC
(1994).
I
t
has
recently
been
suggested
that
a
significant
fraction
of
the
tropospheric
dust
aerosol
is'
influenced
by
human
activities
but
the
radiative
forcing
of
this
component
has
not
yet
been
quantified:
The
range
of
estimates
for
thc
rartistivr
fnrri­?
due
t
o
changes
in
cloud
properties­
caused
by
aerosols
arising
f:
G:
x
iiutnan
activity
(the
indiruct
­effect)
is
unchanged
from­
IPCC
(1994)
at
between
0
and
­1.5
iVm*~.
Sel­
era1
~e
t
y
wclics
confirm
that
the
indirect
effect
of
aerosol
may
have
caused
a
substantial
negative
radiatiw
forcing
since
pre­
..
I
industrial
times,
but
it
remains
very
dilTicu!
t
to
quantify,
more
so
than
the
direct
effect.
\Vhile
no
best
estimate
of
theindirect
forcing
can
'currently
be
made,
the
central
vaiue
of
­0.8
i\
'rn­
z,
has
been
used
in
some
of
the
scenario
cAculntions
dmcribcd
i
n
Sections
B.
9.2
and
F
2.
There
are
no
significant
alterations
since
iPCC
(1994)
in
the
assessment
of
radiative
forcing
caused
by
changes
in
solar
radiatiw
outuut
or
stratospheric
aerosol
loading
resuicing
from
volcanic
eruptrons.
The
estimate
of
radiative
forcing
due
to
changes
in
solar
radiative
output
since
1550
is
+0.3
il'm.
7
(range:
+0.1
to
+0.5).
I3ndiatiL.
e
forcing
due
to
volcanic
aerosols
resultiEe
from
an
individual
eruption
can
be
large
(the
maximum
global
mean
effect
from
the
eruption
of
h
l
r
.
Pinatubo
\vas
­3
to
­4
Wm­
2).
but
lasts
for
only
a
f
e
w
).
ears.
HIDivever.
the
transient
variations
in
both
these
forcings
may
be
important
in
explaining
sornc
of
tile
obsen.
ed
climate
variations
on
decadal
time­
scales.

B.
8
Global
Warming
Potential
(GWP)
The
Global
Warming
Potential
is
an
al:
tempo
to
provide
B
simple
measure
o
f
t
h
e
relative
radiative
effects
of
the
emissions
of
various
greenh'ouse
ga.
ses.
The
indes
is
defined
as
the
cumulative
radiative
*

forcing
between
the
present
and
some
chosen
tido
horizon
caused
by
;ii
unit
mass
of
gas
emitted
nown
expressed
relative
to
that
Far
some
reference
gas
(here
CO,
is
used).
The
hlture
global
warming;
commitment
of
a
greenhousc
gas
over
a
chosen
timi
horizon
can
be
estimated
by
multiplying
the
appropriate
GWPby
the
arnolu~
nt
ofgas
emitted.
For
exan~
plc.
GI'VPs
could
be
used
t
o
compare!
the
efTects
of
reductions
in
C02
(emissions
lrelative
to
reductions
in
methane
emissions,
for
a
specified
time
horizon.
Derivation
of
GWPs
requires
knowledge
of
the
fate
of
the
emitted
gas
and
the
rndiarive­
forcing
due
to
the
amount
remaining
in
thc
atmosphere.
.4lthough
the
GWPs
are
quoted
,as
'single
values.
the
typical
uncertainty
is
r35%.
not
inciuding
the
uncertajnty
in
the
carbon
dioside.
ieference.
Because
GVVPs
are
based
on
the
radiative
forcing
lconcept.
tlhey
are
difficult
to
apply
to
radiatively
important
constituents
that
are
unevenly
distributed
in
the
atmosphere.
No
attem'ot
is
madle
to
define
R
GWP
for
aerosols.
Additionally
the
clnolce
of
time
ho'rizon
>will
cicpcnd
on
policy
cor,;
idera:.
cns.
GWPs
need
to
take
accour!
t
of
any
indirect
effects
of
the
emitted
greenk.
ou&
6
~s
i
f
they
are
to
re!
lect
correctly
future
warming
potentlial.
The
net
GZ'v'Ps
for
the
ozone­
depleting
gases.
ruhich
inlrlude
the
..

..
.
..
direct
"warming"
and
indirect
"cooling"
effects,
have
now
been
estimated.
In
IPCC
(1991),
only
the
direct
GWPs
were
presented
for
these
gases.
The
indirect
effect
reduces
their
GWPs.
but
each
ozone­
depicting
gas
must
be
considered
individually.
The
net
GWPs
of
the
chlorofluorocarbons
(CFCs)
tend
to
be
positive.
while
those
of
the
halons
tend
to
be
negative.
The
calculation
of
indirect
effects
for
a
number
of
other
gases
(e
g
,
NO,,
CO)
is
not
c
u
r
r
e
n
t
l
y
p
o
s
s
i
b
l
e
b
e
c
a
u
s
e
of
inadequate
characterisation
of
many
of
the
atmospheric,
processes
involved.
Updates
or
new
GWPs
are
given
for
a
number
of
kel,
species
(Table
4).
based
on
improved
or
new
estimates
of
atmospheric
lifetimes,
molecular
r
a
d
i
a
t
i
v
e
f
o
r
c
i
n
g
f
a
c
t
o
r
s
.
a
n
d
i
m
p
r
o
v
e
d
representation
of
the
carbon
cycle.
Revised
lifetimes
for
gases
destroyed
by
chemical
reactions
in
the
Eotver
atmosphere
(particularly
methane,
HCFCs
and
HFCs
)
have
resulted
in
GiVPs
that
are
slightly
1ov.
w­
(typically
by
10­
15%
0)
than
those
cited
in
IPCC
(19941.
The
IPCC
definition
of
GWP
is
based
on
calculating
the
relative
radiative
impact
'of
a
release
of
a.
trace
gas
over
a
time
horizon
in
a
constant
background
atmosphere.
In
a
future
atmosphere
with
larger
CO2
concentrations,
such
as
occur
in
all
of
the
IPCC
emission
scenarios
(see
Figure
5b).
we
wduid
calculate
slightly
larger
GWP
values
than
those
given
in
Table
4.
id
B.
9
Emissions
and
concentrations
of
greenhouse
gases
and
aerosols
in
the
future
B.
9.1
The
IS92
emission
scenarios
The
projection
of
future
anthropogenic
climate
c
h
a
n
g
e
d
e
p
e
n
d
s
,
a
m
o
n
g
o
t
h
e
r
t
h
i
n
g
s
,
o
n
assumptions
made
about
future
emissions
of
greenhouse
gases
and
aerosol
precursors
and
the
proportion
of
emissions
remaining
in
the
atmosphere.
Here
we
consider
the
1592
emission
scenarios
(IS92a
to
D
which
were
first
discussed
in
IPCC
(1992).
The
IS92
emission
scenarios
extend
to
the
year
21100
and
include
emissions
of
COz.
CH4,
NzO,
the
halocarbons
(CFCs
and
their
substitute
HCFCs
and
HFCs),
precursors
of
tropospheric
ozone
and
bul!
pt!:
Itc
aerosols
and
z~
rosols
from
biomass
burning.
A
wide
range
of
assumptions
regarding
f
u
t
w
p
economic,
demographic.
and
policy
factors
are
encompassed
(IPCC.
1992).
In
this
report,
the
emissions
of
chlorine­
sild
bromine­
containing
.
..
.
..
.~

..

~
.
~
'.
"
..

25
Table
4:
Globul
Wurming
Potential
referenced
to
the
updated
decay
response
for
the
Bern
carbor:
cgclc
­
and
future
C02
atmospheric
concentrations
held
constant
at
current
iecels.

Species
Chemical
Lifetime
Global
\!
'arming
Potential
Formula
(T
h
e
Horizon)
(years)
20
years
100
years
500
years
Methane*
CH4
1253
56
21
6.5
Kitrous
oxide
X20
120
280
310
170
26
halocarbons
listed
:II
IS92
u
r
e
assumed
to
be
phased
ou&
under
:he
blontreal
Protocol
and
it5
Adjustments
and
;kmendnnenI:
s
and
so
a
single
revised
future
emissioa
scenario
for
these
gases
is
incorporated
in
all
oi'
:he
1592
xenarios.
Emissions
of
indi<,
idual
HFCs
are
based
on
the
original
IS92
scenari.
iis,
aichourh
they
do
n
o
t
reflecr
current
markets.
CO,
emission:;
for
the
si4
scenarios
are
shown
in
Figure
3?..
The
calculation
3
;
future
concentrations
of
greenhouse
gases.
g:
ven
certain
emissions,
entaiis
modelling
the
processes
tilet
transform
and
remove
the
different.
gases
from
the
atmosphere.
For
esample,
future
concentrations
of
C
0
2
are
calculated
using
rnodt.
1~
of
the
carbon
cycle
which
m
o
d
e
l
t
h
e
e
x
c
h
a
q
e
s
of
COz
bletiveen
t
h
e
a
t
m
o
s
p
h
e
r
e
a
n
d
t
h
e
o
c
e
a
n
s
a
n
d
t
e
r
r
s
s
t
r
l
a
l
biosphere
(see
Section
B.
1);
atmospheric
chemistry
m
o
d
e
l
s
a
r
e
u
s
e
d
to
sirrulatle
the
removal
of
chemically
,active
ga.
sss
such
85
methalne.
All
the
IS92
emission
scenarios,
even
IS92c.
imply
increases'
in
greenhouse
gas
concentrations
from
1990
to
2100
(e.
g.,
CO?
increases
range
from.
35
to
170%
(Figure
5b);
CH2
From
2'2
to
175%;
and
N
2
0
from
26
to
,40%).

dependent
on
the
tconcentration
of
the
gas
and
ti,;
strength
with
which
i
t
absorbs
and
ne­
emits
long­
'wave
radiation.
For
suiphnte
aerosol.
the
direct
a
:d
indirect
radiative
forclngs
~e
:­e
calculated
on
th.
8
basis
of
sulphur
emissions
contained
in
the
IS92
scenarios.
The
radiarlT.
e
Forcing
due
to
aerosol
from
biomass
burning
was
assumed
to
remain
constant
at
­0.2
Wm­
7
after
1990.
The
contribution
from
aerosols
is
probabl!
the
tnosc
uncertain
part
of
future
radiative
forcing.
Figure
61,
a
shows
a
single
"best
estimate"
of
historical
radiative
forcing
from
1765,
to
1990
(including
­the
effects
of
aerosols).
foilobved
by
radiative
forcing
for
Scenarios
IS92
a
to
f.
Figures
6b
and
c
show
the
contribution
to
future
mdiative
.
forcing
from
variolus
cornpolxnts
of
the
iS9'a
Scenario;
the
largest
contribution
comes
From
C02,
with
a
radiative
forung
of
~Imost
c
6
Wm.
2
by
2100.
The
negative
forcing
due
tu
tropospheric
aerosols.
ir.
7.
g?!~
bzl!
'!
l.
averay­
2
501's~
pffsets
scmo
of
t
h
p
greenhouse
gas
positive
forcing.
However.
because
tropospheric
aerosols
are
h~
ghiy
variablle
reglonalL).,
their
globa.
li!.
averapcl
radiative
forcing
will
not
adequately
ldescribe
thclir
possible
climatic
impact.
Future
projections
o
f
tenlperature
and
sea
level
based
on
the
IS92
ernlssims
sclenarios
a
r
e
discussed
in
Sectil?
n
f:.
For
greenhouse
gases,,
radiative
forcing
is
'

I
.'
'
..

.
..
,
.­
.
.
I.

..
i"
_,
­

IS92t
IS92a
IS92b
IS92d
IS92c
3
0
J
"J
"'
J
I
f
2000
,
2020
21340
2060
2080
2100
..

u
a
Year
__.
.­.
IS92eIS92f
.
2000
~

2020
2040
2060
2080
2100
..
..
Year
Figure
5:
[a)
Total
anthrbpogenic
C02
emissions
under
the
.
IS92
emission
scenarios
and
(3)
the
resulting
atmospheric
CQz
concentrations
calculateld
using
the
'Bern'
carbon
cycle
modelhnd
the
carbon
bludget
for
the
1980s
shown
in
Tdlbie2.
',
:
28
..
.
.
_.
B.
9.2
Stabilisation
o
f
greenhouse
gas
and
aerosol
concentrations
An
important
questi;
to
consider
is:
how
might
greenhouse
gas
concentrations
be'
stabilised
in
the
future?
If
global
CO,
emissions
were
maintained
at
near
current
(1991)
levels,
they
would
lead
to
a
nearly
c
o
n
s
t
a
n
t
r
a
t
e
­
of
increase
in
atmospheric
concentrations
for
at
least
two
centuries,
reaching
about
500
ppmv
(approaching
twice
the
pre­
industrial
concentration
of
280
ppmv)
by
the
end
of
the
21st
century.
In
IPCC
(19941,
carbon
cycle
models
were
used
to
calculate
the
emissions
of
COz
which
would
lead
to
stabilisation
at
a
number
of
different
.concentration
levels
from
350
to
750
ppmv.
The
assumed
concentration
profiles
leading
to
stabilisation
are
shown
in
Figure
7a
(excluding
350
ppmv).
Many
different
stabilisation
levels.
time­
scales
for
achieving
these
levels.
and
routes
to
stabilisation
could
have
been
chosen.
The
choices
made
are
not
intended
to
have
policy
implications;
the
exercise
is
illustrative
of
the
relationship
between
COz
emissions
and
concentrations.
Those
in
Figure
i
a
assume'
a
smooth
'transition
from
the
current
average
rate
of
CO,
concentration
increase
to
.
stabilisation.
To
a
first
approximation,
the
stabilised
concentration
level
depends
more
upon
the
accumulated
alnount
of
carbon
emitted
up
to
the
time
of
stabilisation.
than
upon
the
exact
Concentration
path
followed
en
route
to
stabilisation.
New
results
have
been
produced
to
take
account
of
the
revised
carbon
budget
for
the
1980s
(Table
2).
but
the
main
conclusion.
that
stabilisation
of
concentration
requires
emissions
eventually
to
drop
.

well
below
current
levels.
remains
unchanged
from
IPCC
(1994)
(Figure
ibl.
Because
the
new
budget
implies
a
reduced
terrestrial
sink.
the
allowable
emissions
to
achieve
stabilisation
are
up
to
10%
lower
than
those
in
IPCC
(1994).
In
addition,
these
calculations
have
been
extended
to
include
alternative
pathways
towards
stabilisation
(Figure
7a)
and
a
higher
stabilisation
level
(1000
ppmv).
The
alternative
pathways
assume
higher
emissions
in
the
early
years,
but
require
steeper
reductions
in
stabilisation
case
allo~
vs
higher
maximum
emissions,
but
still
requires
a
decline
to
current
levels
.by
about
240
years
from
now
and
further
reductions
thereafter
(Figure
7b).
cL.,&
idL;
a
ILt;
u~
)c
a
t
s
(1.1gule
7bj.
­Tile
ibbd
ppr11c­
­
.,.
.­.
Year
F
i
p
m
7:
(a)
CO,
concentration
profiles
1radii;
g
t
o
stabihsation
at
450,
550.
650
and
750
pprnvJol!
iou~
ing
the
pathuays
defined
in
IPCC(
1994)
(solid
curms)
and
for
p
a
t
h
w
y
s
that
allow
emissions
to
follow
lS32a
plntil
at
least
2000
(dashed
curves).
A
single
projile
that
srabiiises
at
a
Ccl,
concentration
of
IO00
ppmv
and
folious
1592a
emissiwu
until
at
least
2000
has
also
been
deflned.
(b!
cO,
emissims
Leading
to
stabilisation
at
concentrarions
ofi'30.
550,
6.70.
750
and
1000
ppmv
following
rhe
p
r
a
J
k
s
shorrn
I
in
[a).
Current
anthropogenic
CO,
emissions
and
those
f
o
r
IS92a
'Ire
shown
for
comparison.
The
ca!
cn!
c!
ions
ltse
the
'
B
e
n
'
'
carbon
cycle
model
and
the
carboll
budgetybr
the
1980s
shown
in
Table
2.
­.
Table
5:
Total
anthropogenic
CO,
emissions
accumulatedfrom
1997
to
2100
inclusive
(Gt&).
All
values
were
calculated
using
the
­
carbon
budget
for
1980s
shown
in
Table
2
and
the
Bern
carbon
3
_.
cycle
model.

Case
Accumulated
C
0
2
emissions
1991
to
2100
[GtC)

IS92
scenarios
c
770
d
980
..
b
1430
.
­a
1500
..
f
1830
.
­.
.
e
2190
...
..
....
..
..
........
..
..
.~
~
............
...........................
...
...
.......
.
.'
.....
,.
­
­
..
.
­
_.;
..
..
..

".
The
accumulated
anthropogenic
COz
emissions
from
1991
to
2100
inclusive
are
shown
in
Table
5
for
the
profiles
leading
to
stabilisation
at
450,
550,
650,
750
and
1000
ppmv
via
the
profiles
shown
in
Figure
7
a
a
n
d
,
for
comparison,
the
'
IS92
emission
scenarios.
These
values
are
calculated
using
the
."
Bern"
carbon
cycle
model.
Based
on
the
results
in
IPCC
(1994)
it
is
estimated
that
values
calculated
with
different
carbon
cycle
models
could
be
up
to
approximately
15%
higher
.or,
lower
than
those
presented
here.
If
methane
emissions
were
to
remain
constant
at
1984­
1994
levels
(i.
e.,
those
sustaining
an
..

atmospheric
trend
of
+10
ppbv/
yr),
the
methane
concentration
would
rise
to
about
1850
ppbv
over
the
next
40
years.
If
methane
emissions
were
to
remain
constant
at
their
current
(1994)
levels
(Le.,
those
sustaining
an
atmospheric
trend
of
Bppbv/
yr),
the
methane
concentratinn
wnqlr!
rise
fn
rhntit
!c?
n
..
ppbv
over
the
next
40
years.
If
emissions
were
cut
by
about
30
Tg(
CH4)/
yr
(about
8%
of
current
anthropogenic
emissionls),
CH4
concentrations
would
remain
at
today's
levels.
These
estimates
are
lower
than
those
in
IPCC
(1994).
If
emissions
of
N20
were
held
constant
at
toda!
's
level.
the
concentration
would
climb
from
312
ppbv
to
about
400
ppbv
over
several
hundred
years.
In
order
for
the
concentration
to
be
stabilised
near
current
levels.
anthropogenic
sources
would
need
to
be
reduced
by
more
than
50%.
Stabilisation
of
PFCs
and
SF6
concentrations
can
only
be
achieved
effectively
by
stopping
emissions.
Because
of
their
short
lifetime,
future
tropospheric
aerosol
concentrations
would
respond
almost
immediately
to
changes
in
emissions.
For
esample.
control
of
sulphur
emissions
would
immediately
reduce
the
amount
of
sulphate
aerosol
in
the
qt­
7ncnhn­
n
......
........

.­
....
".
.
­
..
I
'
.
,.
..
I
C.
Observed
Trends
and
Patterns
general
and
desertification
could
have
contributed
only
a
small
part
(a
few
hundredths
of
a
degree)
of
I
Section
B
demonstrated
that
human
activities
have
the
overall
global
warming,
although
urbanisation
,
influences
may
have
been
important
in
sonle
regions.
Indirect
indicators,
such
'
as
borehole
temperatures
and
glacier
shrinkage,
provide
independent
support
for
the
observed
warming.
Recent
years
have
been
among
the
warmest
since
1860,
Le..
in
the
period
of
instrumental
record.
The
warming
has
not
been
globally
uniform.
The
r
e
c
e
n
t
w
a
r
m
t
h
h
a
s
b
e
e
n
g
r
e
a
t
e
s
t
o
v
e
r
t
h
e
1
continents
between
40%
'
and
70"
N.
A
fen.
areas.

C.
l
Has
the
climate
warmed?
such
as
the
North
Atlantic
Ocean
north
of
30's.
and
Global
average
surface
air
temperature,
excluding
some
surrounding
land
areas,
have
cooled
in
recent
Antarctica,
is
about
15°
C.
Year­
to­
year
temperature
'
decades
(Figure
9).
changes
can
be
computed
with
much
more
As
predicted
in
!Pee
(1992)
and
discussed
in
confidence
than
the
absolute
global
average
IPCC
(19941,
relatively
cooler
global
surface
aut1
temperature.
tropospheric
temperatures
(by
about
0.5"
C)
and
a
T
h
e
m
e
a
n
global
s
u
r
f
a
c
e
t
e
m
p
e
r
a
t
u
r
e
h
a
s
relatively
warmer
lower
stratosphere
(by
about
increased
by
about
0.3"
to
0.6"
C
since
the
late
19th
1.5OC)
were
observed
in
1992
and
eariy
1003,
century,
and
by
about
0.2"
to
0
.X
Over
the
last
30
following
the
1991
eruption
of
&It.
Pinatubo.
years,
the
period
with
most
credible
data
(see
Figure
it'armer
temperatures
at
the
surface
and
i
n
the
8
which
shows
data
up
to
the
end
of
1994).
The
'
l
o
w
e
r
.
t
r
o
p
o
s
p
h
e
r
e
.
a
n
d
a
cooler
lower
1
in
Climate
and
Sea
Level
changed
the
concentrations
and
distributions
'Of
greenhouse
gases
and
aerosols
over
the
20th
1
century;
this
section
discusses
the
changes
in
temperature,
precipitation
(and
related
hydrological
variables),
climate
variability
and
sea
level
that
have
been
observed
over
the
same
period.
Whether
the
observed
changes
are
in
part
induced
by
human
1
i
activities
is
considered
in
Section
E.

,
j
I
warming
occurrcd
largely
,during
two
periods,
stratosphere,
reappeared
in
1994
following
the
i
.­

I.

changed
since
the
IPCC
(1990)
and
IPCC
(1992J.;
The
general
tendency
toward
reduced
daily
Warming
is
evident
in
both
sea
surface
and
land­
temperature
range­
over
land,
at
least
since
the
based
surface
air
temperatures.
Urbanisation
in
middle
of
the
20th
century,
noted
in
IPCC
(1992),

­
temperatiirc>
s
1%
'1
IS6
I
IO
1994.
re1utir.
r
tu
1961
10
'
.
1990.
The
solid
c~~
rct'
represehts
snluothircg
$IIW
annrcul
I?
alws
slronx
69
t
l
w
bars
to
suppress
srtb­
tir~
ac!
nl
time­
scale
rariutiwn,
The
dashed
sncoutirecl
~1
1
1
1
~
is
thL,
corresponclirry
w
w
l
t
J
i
m
c
1860
1880
1900
1920
.
1940
1960
1980
2000
Year
::
I
..
­2
­1.5
­1
­0.5
0
0.5
1
1.5
2
Figure
9:
Change
(fro112
1955T4
to
1975­
9­
1)
of
arlnrtal
land­
snrface
air
temperature
and
sen
strrfnce
ternper~
trrre.
­

has
been
confirmed
with
more
data
(which
have
now
been
analysed
for
more
than
40%
of
the
global
land
area).
The
range
has
decreased
in
many
areas
because
nights
have
warmed
more
than
days.
Minimum
temperatures
have
typically
increased
twice
as
much
as
maximum
temperatures
over
the
last
40
years.
A
likely
esplanation,
in
addition
to
the
effects
of
enhanced
greenhouse
gases.
is
an
increase
in
cloud
cover
which
has
been
observed
in
many
of
the
areas
with
reduced
diurnal
temperature
range.
An
increase
in
cloud
reduces
diurnal
temperature
range
both
by
obstructing
daytime
sunshine,
and
by
preventing
the
escape
of
terrestrial
radiation
at
night.
.Anthropogenic
aerosols
may
also
have
an
influence
on
daily
temperature
range.
Temperature
trends
in
the
free
atmosphere
are
more
difficult
to
determine
than
at
the
surface
as
there
are
fewer
data
and
the
records
.are
much
shorter.
Radiosonde
data
which
are
available
since
the
1950s
show
warming
trends
of
around
0.1"
C
per
decade.
as
at
the
surface,
but
since
19T9
when
satellite
data
of
global
tropospheric
temperatures
became
available,
there
appears.
to
have
been
a
J
..~.,L
­1:
­!.
4
<u>:
iilg
(abdui
­0.
ciO'i
per
decade),
rvtlereas
.
.
surface
measurements
still
show
a
warming.
Thpsp
apparently
contradictory
trends
can
be
reconciled
if
the
diverse
response
of
the
troposphere
and
surface
to
short­
term
events
such
as
volcanic
eruptions
and'
El
NiAo
are
taken
into
account.
After
adjustment
for
..

32
*­
..
these
transient
effects,
both
tropospheric
and
surface
data
show
slight
warming
(about
0.1"
C
per
decade
for
the
troposphere
and
nearly
0.2'C
per
decade
at
the
surface)
sincc
1973.
Cooling
of
the
lowcr
stratosphere
has
been
observed
since
1979
both
bq'
satcllitcs
and
weather
balloons.
as
noted
in
IPCC
(1992)
and
IPCC
(1994).
Current
global
mean
stratospheric
tcnlpcrnturcs
are
the
coldest
obsen­
ecl
in
thc
relatively
short
period
of
the
record.
Reduced
stratospheric
tcmpcrature
has
been
projected
to
accompany
both
ozonc
losses
in
the
lower
stratosphere
and
atmospheric
increases
of
carbon
dioside.

C.
2
Is
the
20th
century.
warming
unusual?
In
order
to
.establish
whether
the
20th
century
warming
'is
part
of
the
natural
variability
of
the
climate
system
or
a
response
to
anthropogenic
forcing.
information
is
needed
on
climate
variability
on
relevant
time­
scales.
As
an
average
over
the
Northe'rn
Hemisphere
for
summer.
recent
decades.
appear
to
be
the
warmest
since
a
t
least
1400
from
tilt.
illiiiieu
avauade
evidence
(Figure
10).
The
warminn
over
t
h
P
past
century
began
d1.1ri~
g
one
qT
the
colder
periods
of
the
last
600
years.
Prior
to
1400
data
are
insufficient
t
o
provide
hemispheric
temperature
esTirnates.
Ice
core
data
fron:
se,<
e:
al
sites
suggest
that
the
20th
century
is
at
least
as
..
warm
a
s
any
century
in
the
past
600
years,
although
the
recent
warming
is
not
exceptional
everywhere.
Large
and
rapid
climatic
changes
occurred
during
the
last
glacial
period
(around
20,000
'to
100.000
years
ago)
and
during
the
transition
period
towards
the
present
interglacial
(the
last
10,000
years,
known
as
the
Holocene).
Changes
in
annual
mean
temperature
of
about
5°
C
occurred
over
a
few
decades,
at
least
in
Greenland
and
the
Korth
Atlantic,
and
were
probably
linked
to
changes
in
oceanic
circulation.
These
rapid
changes
suggest
that
climate
may
be
quite
sensitive
to
internal
or
external
climate
forcings
and
feedbacks.
The
possible
relevance
of
these
rapid
climate
changes
to
future
climate
is
discussed
in
Section
F.
5.
3
Temperatures
have
been
less
variable
during
the
last
10,000
years.
Based
on
the
incomplete
evidence
available,
it
'is
unlikely
that
global
mean
temperatures
have
varied
by
more
than
1'C
in
a
century
during
this
period.
­

C.
3
Has
the
climate
become
wetter?
As
noted
in
IPCC
(1992).
precipitation
has
increased
over
land
in
high
latitudes
of
the
Northern
Hemisphere.
especially
during
the
cold
season.
A
step­
like
decrease
of
precipitation
occurred
a
h
r
the
19GOs
over
the
subtropics
and
tropics
from
Africa
to
Indonesia.
These
changes
are
consistent
with
changes
in
streamflow.
lake
levels
and
soil
moisture
(whcre
data
analyses
are
available).
Precipitation.
averaged
over
global
land
areas.
increased
from
the
start
o
f
the
century
LIP
to
about
19GO.
Since
about
1980
precipitation
over
land
has
decreased
(Figure
11).
There
is
evidence
to
suggest
increased
precipitation
over
the
central
equatorial
Pacific
Ocean
in
recent
decades,
with
decreases
to
the
north
and
south.
Lack
of
data
prevents
us
from
reaching
firm
conclusions
about
other
precipitation
changes
over
the
ocean.
Estimates
suggest
that
evaporation
may
have
increased
over
the
tropic.
al
oceans
(although
not
everywhere)
but
decreased
over
large
portions
of
Asia
and
North
America.
There
has
also
been
an
observed
increase
in
atmospheric
water
vapour
in
the
tropics,
at
leasr
since
1Yi3.
'Cloudiness
appears'
to
have
increased
sinc'e
the
1950s
over
the
oceans.
In
many
land
areas
where
the
daily
temperature
range
has
decreased
(see
Section
C.
1).
cloudiness
increased
from
the
1950s
to
at
least
the
1970s.
I
..
Northern
Hemisphere
Summer
(JJA)

o_
0.2
Figure
10:
Decadal
summer
(June
to
August)
temperature
index
for
the
Northern
Hemisphere
(to
19i0­
19iqJ
based
on
16
proxy
records
(tree­
rings.
ice
cores,
docwnentnrzJ
records)
from
North
America.
Europe
and
East
Asia.
The
thin
line
is
a
smoothing
of
the
same
data.
.­
lnomnlies
are
relative
to
1961
to
1990.

a
1900
*
1920
1940
1950
.
1980
Year
Figure
1
I:
Changes
in
land­
surface
precipitatiou
arernged
over
regions
between
55's
and
8SN.
Annual
precipitation
depurtures
from
the.
1961­
90
period
are
depicted
by
the
hollow
bars.
The
continuous
curue
is
a
smoothing
of
(he
sclr71c'

data.

..

Snow
cover
extent
over
the
Northern
Hemisphere
land
surface
has
been
consistently
below
the
21­
pear
average
(1974
to
19943
since
19SS.
Snow­
radiation
feedback
has
amplified
springtitlie
warming­
over
mid­
to
high
latitude'
Northern
Hemisphere
land
areas.
A
summary
of
observed
climate
trends
is
sholvn
in
Figure
12.
..

3
3
(a)
Temperature
indicators
(0.6
"C
decrease
1979­
94)
***
stratosphere
*'
0.3
"C
increase
1958­
94
troposphere
*"
little
change
1979­
94
..
0
.
4
.

***
N.
H.
spilng
snow
cover
I
(1
0%
decrease1973­
94)
'\,
.

­­­­­­­­­""""""""­
***
near
surface
air
C"""""""

..........
­;**
land
night­
time
air
­.;
..
'.!.
'.
'
.......
.:.
...
­
.­
......
***
near
surface
ocean
(0.3­
0.6
"C
increase
since
temperatures
rising
faster
.:
**
sea
ice
(1
973­
94)
.
~

..

late
19th
century)
than
daytimetemperatures
.
during
1990s
'
'
N.
H.
below
avg.
(1951­
90)
:
.:.,:
1,
...
~

......
...
................
..
..........
,_.
.:
':
Tf
groundtemperaturesS.
H.
avg.
.....
...
.....
..
(mostlywarming)

..
33
..
...
_..
t
..
,
I
*.
,
"
..
,
.­

....
....
...
...
...
........
......
...
..
­.
....
...
­
­.
..
..
'.
.
:
1
..
..
..
­.
..
C.
4
Has
sea
level
risen?
Over
the
last
100
years
global
sea
level
has
risen
by
about
10
to
25
cm,
based
on
analyses
of
tide
gauge
,
records.
A
major
source
of
uncertainty
in
estimating
the
rate
of
rise
is
the
influence
of
'vertical
land
movements,
which
are
included
in
sea
level
measurements
made
by
tide
gauges.
Since
IPCC
(1990),
improved
methods
for
filtering
out
the
effects
of
long­
term
vertical
land
movements,
as
well
as
greater
reliance
on
the
longest
tide­
gauge
records
for
estimating
trends,
have
provided
greater
confidence
that
the
volume
of
ocean
water
has,
in
fact,
been
increaSing
and
causing
sea
level
to
rise
within
the
indicated
range.
It
is
likely
'that
much
of
the
rise
in
sea
level
has
C.
5
Has
the
climate
become
more
variable
and/
or
extreme?
Many
of
the
impacts
of
climate
change
may
result
from
changes
in
climate
variability
or
estreme
weather
events.
Some
reports
have
already
suggested
an
increase
in
variability
or
extremes
h
a
s
t
a
k
e
n
place
in
recent
decades.
Do
meteorological
records
support
this?
There
are
inadequate
data
to
determine
whether
consistent
global
changes
in
climate
variability
or
extremes
have
occurred
­over
the
20th
century.
On
regional
scales
there
is
clear
evidence
of
changes
in
some
extremes
and
climate
variability
in$
icators
(e.
g.,
fewer
frosts
in
several
widespread
areas:
an'increase
in
the
proportion
of
scale,
the
warming
and
consequent
espansion
of
the
oceans
may
account
for
about
2
to
7
cm
of
the
observed
rise
in
sea
level,
while
the
observed
retreat
of
glaciers
and
ice­
caps
may
account
for
about
2
to
5
cm.
Other
factors
are
more
difficult
to
quantify.
Changes
in
surface
and
ground
water
storage
may
have
caused
a
small
change
in
sea
level
over
the
last
100
years.
The
rate
of
observed
sea
level
rise.
suggests
that
there
has
been
a
net
positiv?
­contribution
from
the
huge
ice
sheets
of
Greenhpd
and
Antarctica,
but
observations
of
the
ice
sheets
do
not
yet
allow
meaningful
quantitative
estimates
of
their
separate
contributions.
The
ice
sheets
remain
a
major
source
of
uncertainty
in
accounting
for
past
changes
in
sea
level,
because
there
are
insufficient
data'about
these
ice
sheets
over
the
last
100
years.
..
States
of
the
USA).
Some
of
these
changes
have
been
toward
greater
variability:
some
have
been
toward
lower
variability.
There
have
been
relatively
frequent
El
Niiio­
Southern
Oscillation
warm
phase
episodes,
with
only
rare
excursions
into
the
other
estreme
of
the
phenomenon
since
1977,
as
noted
in
IPCC
(1990).
This
behaviour,
and
especially
the
persistent
warm
phase
from
1990
to
mid­
1995.
is
unusual
in
the
last
120
years
(i.
e..
since
instrumental
records
began).
The
relatively
low
rainfall.
over
the
subtropical.
land
areas
in
the
last
two
decades
is
related
to
this
behaviour.
­

..
BOX
2:
What
took
are
used
to
project
future
climate
and
how
­
are
they
used?

3
G
D.
Modelling
Climate
and
(a)
Obse.
wed
Climate
Change
surface
air
temperature
(OC)
December­
Februari
*
Climate
models
which
incorporate,
in
various
degrees
of
complexity.
mathematical
descriptions
of
t
h
e
a
t
m
o
s
p
h
e
r
e
,
o
c
e
a
n
,
l
a
n
d
,
b
i
o
s
p
h
e
r
e
a
n
d
cryosphere.
are
important
tools
for
understanding
climate
and
climate
change
of
the
past,
the
present
cl
A
\J
+:.
r
;&
'j
'.
:
LyF
:
,:,
d;

and
the
future.
These
models.
which
use
primarily
physical
lalvs
and
physically
based
empirical
relations,
are
very
much
more
complete
than.
for
example.
models
based
on
statistical
relationships
used
in
less
quantitative
disciplines.
Detailed
(b)
Model
averaae
surface
air
ternDerature
projections
of
future
climate
change
rely
heavily
on
coupled
atmosphere­
ocean
models
(see
Box
2).
How
much
confidence
should
we
have
i
n
predictions
from
such
models?

D.
l
The
basis
for
confidence
in
climate
models
As
discusscd
in
Section
B,
changes
in
the
radiatively
active
trace
gases
in
the
atmosphere
produce
radiative
forcing.
For
cquivalcnt
CO,
concentrations
equal
to
twice
the
pre­
industrial
concentration,
the
positive
radiative
forcing
is
about
+4
\Vm­
'.
To
restore
the
radiative
balance
other
changes
in
climate
must
occur.
The
initial
reaction
is
for
the.
locvcr
atmosphcrc
(the
troposphere)
and
the
Earth's
surface
to
warm:
in
thc
absrncc
of
othcr
changcs.
the
warming
would
be
about
1.2"
C.
I­
fon.
cvrtr.
hcating
not
only
changes
tcmpcraturc's.
but
also
altcrs
other
aspects
of
the
cliunate
systcnl
and
various
feedbacks
arc
invokcd
(see
Section
D.
2).
The
key
role
of
climate
moclcls
is
to
quantify
those
fecdbacks
and
determine
the
ovcrall
climate
response.
Further,
.the
warming
and
othor
clilnatc
effects
will
not
be
uniform
over
thc
Earth's
surfacc;
an
important
role
of
models
is,
to
simulate
possiblc
continental
and
regional
scalc
climate
responscs.
Climate
models
include,
bascd
on
our
current
undcrstanding.
the
most
important
large
scalc
.physical
processes
govcrning
the
climate
system.
Climate
models
have
improved
since
IPCC
(1990).
but
so
too
has
our
unclcrstanding
of
thc
complcsity
of
the
climate
system
and
thc
recognition
of
the
need
to
include
additional
processes.
In
uruec
to
assess
tile
i
;t
I
u
c
ui'
't
1il"
ici
hi­
projections
of
future
climate.
its
simulated
climate
can
be
compared
with
known
features
of
the
observed
current
climate
and.
to
a
less
satisfactory
degree.
with
the
morc
limited
information
from
significantly
different
past
climate
states.
I
t
is
,
..

..

..
..
.
­.
..
..
I
(4
Observed
precipitation
rate
(rndday)
June­
August
(d)
Model
average
precipitationrate
3i
important
to
realise
that
even
though
a
model
may
have
deficiencies,
it
can
still
be
of
value
in
quantifying
the
climate
response
to
anthropogenic
climate
forcing
(see
also
Bos
2).
Several
factors
give
us
some
confidence
in
the
ability
of
climate
models
t
o
simulate
important
aspects
of
anthropogenic
climate
change
in
response
to
anticipated
changes
in
atmospheric
composition:

(i)
The
most
successful
climate
models
are
able
to
simulate
the
important
large­
scale
features
of
the
components
of
the
climate
system
well,
including
seasonal,
geographical
and
vertical
variations
which
are
a
consequence
of
the
variation
of
forcing
and
dynamics
in
space
and
time.
For
example,
Figure
13
'shows
the
geographical
distribution
of
December
to
February
surface
temperature
a@
June
to
August
precipitation
.simulated
by
comprehensive
coupled
atmosphere­
ocean
models
of
the
type
used
for
climate
prediction.
compared
nith
observations.
The
large
scale
features
are
reasonably
well
captured
by
the
models,
although
at
regional
scales
more
discrepancies
can
be
seen.
Other
seasons
are
similarly
well
simulated.
indicating
the
ability
of
models
to
reproduce
the
seasonal
cycle
in
response
to
changes
in
solar
forcing.
The
improvement
since
IPCC
(1990)
is
that
this
level
of
a,
ccuracy
is
achieved
in
models
with­
a
fully­
interactive
ocean
as
compared
to
the
majority
of
models
that
employed
simpler
schemes
used
in
1990.

(ii)
Many
climate
changes
are
consistently
projected
by
different
models
in
response
to
greenhouse
gases
and
aerosols
and
can
be
explained
in
terms
of
physical
processes
which
are
kn0Lr.
n
to
be
operating
in
the
real
world.
for
example.
the
maximum
ivarming
in
high
northern
latitudes
in
winter
(see
Section
F).

(iii)
The
models
reproduce
with
reasonable
fidelity
other
less
obvious
variations
in
climate
due
to
changes
in
forcing:

*
Some
atmospheric
.models
when
forced'
with
observed
sea
surface
temperature
variations
can
reproduce
with
moderate
to
good
skill
several
regional
climate
variations,
especially
in
parts
of
the
tropics
and
sub­
tropics.
For
'esample.
a
s
p
e
c
t
s
o
f
the
l
a
r
g
e
s
c
a
l
e
i
n
t
e
r
a
n
n
u
a
l
.­.?.:;;
Lc:
c
ELL~
G~
L~
U,
A>
UI.
GI
tile
iruplcai
Packtic,
­r
e
l
a
t
i
n
g
t
o
t
h
e
El
Nifio­
Southern
Oscillation
phenomenon
are
captured,
as
are
interannual
Variations
in
rainfall
in
north­
east
Brazil
and
to
some
extent
decadal
variations
in
rainfall
over
the
Sahel.
dl
3s
*
AS
discussed
in
IPCC
(199.11,
stratospheric
aerosols
resulting
from
the
eruption
of
hit.
Pinatubo
in
Jtine
1991
gave
rise
to
a
short­
lived
negative
globel
mean
radiative
forcing
of
rhe
troposphere
which
peaked
at
­3
to
­4
IVm.
2
a
few
months
after
the
eruption
and
had
v
i
r
t
~~;~i
~­
disappeared
by
about
the
end
of
1994.
.A
clin:;:
e
model
was
used
to
predict
global
tempera:
ure
variations
betwen
the
time
of
the
eruption
a2d
the
end
of
1994
and
the
results
agreed
c
l
~j
;.!~
with
observations
(Figure
11).
Such
a,
Ureemenr
increases
confidence
in
the
ability
ofcIin1e:
e
models
to
respond
in
a
realistic
way
to
transienr.
planetary­
scale
radiative
forcings
of
i
a
r
g
magnitude.

0
Previous
IPCC
reports
demonstrated
the
abilj;;:
.
of
models
to
simulate
some
known
features
of
palaeoclimate.
Only
modest
progress
has
been
made
in
this
area,
mainly
because
of
the
pauciv
of
reliable
data
for
comparison.

0
Currently
available
model
simulations
of
global
mean
surface
temperature
trend
m
r
the
past
half
century
show
closer
agreement
wirh
observations
when
the
simulations
include
the
likely
effect
of
aerosol
in
addition
to
greenhouse
gases
(Figure
15).

(iv)
The
model
results
eshibit
"natural"
variability
on
a
wide
range
of
rime­
and
space­
scales
which
is
broadly
comparable
to
that
observed.
This
"natural"
.Variability
arises
from
the
internal
processes
at
work
in
the
climate
system
and
not
from
changes
in
esternal
forcing.
Variab'ility
is
a
very
important
aspect
of
the
behaviour
of
the
climate
system
and
has
important
implications
for
the
detection
of
climate
change
(see
Section
E).
The
year
to
year
variations
of
surface
air
temperature
for
the
current
climate
are
moderately
realistic
in
model
simulations
at
the
larger
space­
scales.
For
example
the
smaller
variability
over
the
oceans
compared
with
continental
interiors
is
captured.
Too
low
interannual
variability
of
the
tropical
east
and
central
Pacific
Ocean
temperatures
associated
with
the
.El
Nifio­
Southern
Oscillation
(ENSO)
phenomenon
is
one
deficiency.
No
current
coupled
atmosphere­
ocean
model
simulates
a
l
l
aspects
of
LI'sbu
events,
bul
some
of
the
0bserve.
d
interannual
variations
in
thP
almwphere
nssbcintccl
rT:
ith
t
h
e
s
events
are
captured.
..

Climate
models
are
c
a
l
i
b
r
a
t
e
d
,
i
n
p
a
r
t
,
by
*
the
systematic
adjustments
(the
so­
called
flux
m
­
adjustments)
that
are
used
in
some
models
at
the
'
atmosphere­
ocean
interface
in
order
to
bring
the
$
'''r
simulated
climate
closer
to.
the
observed
state.
E
1
These
adjustments
are
used
to
compensate
for
models,
are
'used
to
ensure
that
the
simulated
present
day
climate
is
realistic
and
hence
that
c
l
i
m
a
t
e
f
e
e
d
b
a
c
k
p
r
o
c
e
s
s
e
s
o
p
e
r
a
t
e
i
n
t
h
e
Year
generally
be
traced
to
deficiencies
in
the
simulation
of
current
climate
in
the
unadjusted
models.
for
example,
systematic
errors
in
sea
ice.
The
main
unknown
regarding
the
use
of
adjustments
in
models
is
the
extent
to
which
they
allow
important
against
known
climate
variations
including
the.;
5
seasonal
cycle
and
the
perturbations
mentivncd
above.
This
provides
some
conficlence
in
their
use
3
0.5
activities.

improvements.
e.
g..
the
successful
incorporation
of
a
d
d
i
t
i
o
n
a
l
p
h
y
s
i
c
a
l
p
r
o
c
e
s
s
e
s
(s
u
c
h
.
a
s
c
l
o
u
d
..
.
microphysics
and
the
radiative
effects
of
sulphate
Figure
15:
Simulated
global
annual
mean
a­
arming
from
aerosols)
into
global
coupled
models.
and
the
1860
to
1990
allowing
for
increases
in
greenhouse
gases
only
(dashed
curve)
and
greenhouse
gases
and
sulphate
improvement
in
such
models'
simulation
of
the
wrosols
(solid
curve),
compared
with
observed
changes
observed
changes
in
climate
over
recent
decades.
over
the
same
period.
Further
confidence
will
be
gained
as
models
continue
to
improve.

D.
2
Climate
model
feedbacks
and
uncertainties
2.5"
C.
The
range
of
the
estimate
arises
from
the
initial
response.
The
likely
equilibrium
response
have
emerged
to
change
Lhese
estim&
es
of
th5
of
global
surface
temperature
to
a
doubling
of
climate
sensitivity.
The
present
activities
regarding
equivalent
carbon
dioxide
concentration
(the
incorporation
of
these
feedback
processes
in
models
"climate
sensitivity")
was
estimated
in
1990
to
be
in
are
described
below.

..
..
Water
vapour
feedback
An
increase
in
the
temperature
of
the
atmosphere
increases
its
water
holding
capacity
and
is
expected
to
be
accompanied
by
an
increase
in
the
amount
of
water
vapour.
Since
water
vapour
is
a
powerful
greenhouse
gas,
the
increased
water
vapour
would
in
turn
lead
to
a
further
enhancement
of
the
greenhouse
effect
(a
positive
feedback).
About
half
of
this
feedback
depends
on
water
vapour
in
the
upper
troposphere.
whose
origin
and
response
to
surface
temperature
increase
is
not
fully
understood.
Feedback
by
water
vapour
in
the
lower
troposplwe
is
unquestionably
positi1.
e
and
the
preponclcrence
of
evidence
points
to
the
same
conclusion.
for
upper
tropospheric
water
vapour.

'
Feedbacks
resulting
from
changes$
the
decrease
of
temperature
with
height
can
partially
compensate
the
water
vapour
feedback.
I
Cloud/
radiative
feedback
Several
processes
are
involved
in
cloud/
radiative
feedback.
Clouds
can
both
absorb
and
reflect
solar
radiation
(which
cools
the
surface)
and
absorb
and
emit
long­
wave
radiation
(which
warms
the
surface).
depending
0.
n
cloud
height.
thickness
and
cloud
radiative
properties.
The
radiative
properties
of
clouds
clcpcnd
on
the
evolution
of
atmospheric
watcr
in
its
vapour,
liquid
and
kii
phases
and
upon
atmosphc!
ric
aerosols.
The
processes
are
complcs
and.
although
considerable
progress
has
been
made
since
II'CC
(1990)
in
describing
and
modelling
those
cloud
pr~
c:
c!
sses
thnt
arc
most
important
for
dctermilling
radiative
and
t1rnce
temprrntrtrc
changcs.
thcir
uncertainty
represents
a
significant
source
of
potcntial
error
in
climate
simulation.
This
potrntinl
error
can
be
estimated
by
first
noting
that
if
clouds
and
sea
ice
are
kept
k
e
d
accorcling
to
thcir
observed
distributions
and
propertic%
climate
models
would
a
l
l
report
climate
sensitivitic.
s
i
n
the
range
of
2
to
3°
C.
&Ioclellers
have
shown
foi.
various
assumptions
that
physically
plausible
changes
in,
cloud
distribution
could
either
as
much
as
double
the
warming
expected
'for
fixed
clouds
or.
on
the
other
hand.
reduce
it
by
up
to
1°
C.
The
range
in
estimated
climate
sensitivity
of
1.5
to
3.5"
C
is
Iarg~
ly
dictated
by
this
uncertainty.

Ocean
circn.
'­
':
'5,2
Oceans
play
an
important
role
in
climate
because
they
c
a
q
large
amounts
of
heat
from
the
tropics
to
the
poles.
They
also
store
large
amounts
of
heat.
carbon
and
CO,
and
are
a
major
source
of
water
to
osphrre
(through
evaporation).
Coupling
of
I
'
....
.
'.
.
­
..
.
..~..
.
.­
.
,.
.
atmospheric
and
oceanic
GCMs
(see
B~~
2)
improves
the
physical
realism
of
models
used
for
projections
Of
fUtUre
dimate
change,
particularly
the
timing
and
regional
distribution
of
the
changes.
Several
models
show
a
decrease
or
only
margilyal
increase
of
sea
surface
temperatures
in
the
northel­
E
North
Atlantic
in
response
to
increasing
greenhouse
g
a
s
e
s
,
r
e
l
a
t
e
d
to
a
s1on.
ing
down
of
the
thermohaline
circulation
as
the
climate
warms.
This
represents
a
local
negative
temperature
feedback.
although
changes
in
cloud
cover
might
be
an
important
factor.
The
main
influence
of
the
oceans
on
simulations
of
climate
change
occurs
because
of
their
large
heat
capacity,
ivhich
introduces
a
dela?
in
warming
that
is
not
uniform
spatially.

Ice
and
snow
albedo
feedback
An
ice
o
r
snow
covered
surface
strongly
reflecrs
solar
radiation
(i.
e..
it
has
a
high
"albedo").
As
solne
ice
melts
at
the
warmer
surface,
less
solar
radiation
is
reflected
leading
to
further
warming
(a
positive
feedback).
but
this
is
complicated
by
clouds,
leads
(areas
of
open
water
in
sea
ice)
and
snowcover.
The
realism
of
simulated
sea
ice
cover
varies
considerably
between
models.
although
sea
ice
models
that
include
ice
dynamics
are
showing
increased
accuracy.

.
Land­
surface/
atrnosphere
interactions
Anthropogenic
climate
changes,
e.
g.,
increased
temperature.
changes
in
precipitation,
changes
in
net
radiative
heating
and
the
direct
effects
of
CO,.
will
influence
the
state
of
the
lend
surface
(soil
moisture.
albedo.
roughness.
vegetation).
In
turn.
the
altered
land
surface
can
feed
back
and
alter
the
overlying
atmosphere
(precipitation,
water
vapour.
clouds).
Changes
in
the
composition
and
structure
of
ecosystems
can
alter
not
only
physical
climate.
but
also
the
biogeochemical
cycles
'
[see
Section
B).
Although
land­
surface
schemes
.
used
in
current
GChls
may
be
more
sophisticated
than
in
IPCC
(1990).
the
disparity
between
models
in
their
simulation
of
soil
moisture
and
surface
heat
and
moisture
fluses
has
not
been
reduced.
Conhdence
in
calculation
of
regional
projections
of
soil
moisture
changes
in
response
to
greenhouse
gas
and
aerosol
forcing
remains
low.

C
;i
L
k
i
L
d
c
>
11;
~C
~;C
L
~;L
U
I
~
call
powaailg
tuctner
modify
climate
locally
and
regionally
by
altering
thP
exchange
of
water
and
energy
between.
the
lard
surface
and
atmosphere.
For
esample,
forests
spreading
into
tundra
in
a
w
r
m
e
r
worlci
tvould
absorb
a
greater
proportion
of
solar
'energy
and
*

.
...
.
­
..
~.
feedbacks
may
have
important
effects
on
regional
natural
in
origin.
Such
natural
fluctuations
occur
on
climate
change
projection.
a
variety
of
s
p
a
c
e
­
a
n
d
t
i
m
e
­s
c
a
l
e
s
,
a
n
d
c
a
n
b
e
purely
internal
(due
to
complex
interactions
E.
Detection
Of
`Iimate
Change
betiveen
individual
components
of
the
climate
,
and
Attribution
of
Causes
system,
such
as
t
h
e
a
t
m
o
s
p
h
e
r
e
a
n
d
o
c
e
a
n
)
or
respect
to
the
increase
in
global
mean
temperature
natural
variability,
in
the
observations.
This
is
over
the
last
100
years,
IPCC
(1990)
concluded.
that
b
e
c
a
u
s
e
t
h
e
r
e
a
r
e
l
a
r
g
e
u
n
c
e
r
t
a
i
n
t
i
e
s
in
the
the
observed
warming
was
"broadly
consistent
lvirh
.
evaJ,
2tion
and
magnitude
of
both
human
and
natural
predictions
of
climate
models,
but
it
is
also
of
the
forcings,
and
in
the
characteristics
of
natural
same
magnitude
as
natural
climate
variability".
The
internal
variability,
which
translate
to
uncertainties
.
report
went
on
to
esplain
that
"the
observed
in
the
relative
magnitudes
of
signal
and
noise.
increase.
could
be
largely
due
to
this
natural
In
the
modelled
world,
however.
it
is
possible
to
variability;
alternatively
this
variability
and
other
perform
multi­
century
control
experiments
with
no.
human
factors
could
have
offset
a
still
larger
human­
induced
changes
in
greenhouse
gases.
human­
induced
greenhouse
warming".
sulphate
aerosols
or
other
anthropogenic
forcings.
Since
IPCC
(1990).
considerable
progress
has
Since
1990,
a
number
of
such
control
esperiments
been
made­
in
the.
search
for
an
identifiable
human­
have
been
performed
with
coupled
atmosphere­
induced
effect
on
climate.
osean
models,
These
yield
important
information
on
.,
the
patterns,
.
time­
scales,
and
magnitude
of
`the
"internally
generated"
component
of
natural
climate
Espcrimcnts
with
GChIs
are
now
starting
to
'
observed
changes
can
be
plausibly
incorporate
some
of
the
forcing
due
to
huInnn­
.
explained
by
internal
climatic
fluctuations.
but
i
n
d
u
c
e
d
c
h
a
n
g
e
s
i
n
s
u
l
p
h
a
t
e
a
e
r
o
s
o
l
s
a
n
d
only
dne
part
of
the
"total­
llatural
'
stratospheric
ozonc.
Thc
inclusion
o
f
.
these
variability
ofclimate
(since
such
control
runs
do
not
induced
climate
change
from
a
large
(>
18)
number
of
transient
experiments
in
which
coupled
well­
misecl
greenhouse
gases;
see
"equivalent
C02"
only.
These
investigations
compared
observed
in
the
Glossary).
some
of
these
experiments
have
changes
over
the
past
10­
100
years
with
estimates
been
repeated
with
identical
forcing
but
starting
of
internal
or
total
natural
variability
noise
derived
i.
ii,.
i
&.
....
.....­.
L...
igiti:].!
r
l
;v
?.t
P
~+o
t
n
.
Sl.!
rh
frnm
palneodata.
climate
models,
or
statistical
repetitions
help
to
better
define
the
espected
models
fitted
to
observations.
Most.
bur
nor
all
ot
r
.
...
..
,.I
:.,L
+I
,.
cl:
r?
n
,..,,.

natural
fluctuations
of
the
climate
system.

."
1850
1880
1910
1940
1970
2000
Time
(years)

­
0.75
E
5
2
0.50
m
c
0.25
m
p!
.­
x
0.00
m
Ql
p­
0.25
L.

5
I­
­0.50
1850
1880
1910
1940
1970
2000
Time
(years)
Figure
16:
Observed
changesin
global
mean
temperature
over
1861
to
1994
compared
with
those
silldated
using
an
upwelling
diffusion­
energy
balance
climate
model.
The
model
was
runprst
with
forcing
due
to
greenhohe
gases
alone
(a)
and
then
with
greenhouse
gases
and
aerosols
(3).

These
global
mean
results
cannot
establish
a
clear
cause
and
effect
link
between
observed
changes
in
atmospheric
greenhouse
gas
concentrations
,and
changes
in
the
Earth's
surface
temperature.
This
is
the
attribution
issue.
Attribution
is.
difficult
using
global
mean
changes
only
because
of
uncertainties
'.
in
the
histories
and
magnitudes
.of
natural
and
human­
induced
forcings:
there
are
many
possible
combinations
of
these
forcings
that
could
yield
the
same
curve
of
observed
global
mean
temperature
change.
Some
combinations
are
more
plausible
than
others,
but
relatively
few
data
exist
to
constrain
the
range
of
possible
solutions.
Nevertheless,
model­
based
estimates
of
global
temperature
increase
over
the
last
130
years
are
more
easily
reconciled
with
observations
when
the
likely
cooling
effect
of
s,?
lgh,
t"
7prr7CT,
11
is
+",."
:­.­
^,.
^.....
.
..,
I
.
.
.'
­
qualitative
support
for
an
estimated
range
of
clim'ate
sensitivity
consistent
with
that
given
in
IPCC
(1990)
(Figure
16).
I
4
<._.
i_,___
.._..
"..
..,­.,
C
I
r
i
r
V
r
...,
u..
LA
*""""
L
E.
4
Studies
of
patterns
of
change
To
better
address
the
attribution
problem,
a
nu[
l,
ber
of
recent
studies
have
compared
observations
[virh
model­
predicted
patterns
of
temperature­
change
i
n
response
to
anthropogenic
forcing.
The
argu[
l;
enr
underlying
pattern­
based
approaches
is
til>..

different
forcing
mechanisms
("
causes")
may
ha,­,.
d
i
f
f
e
r
e
n
t
p
a
t
t
e
r
n
s
of
response
("
eflectj..,,
particularly
if
one
considers
the
full
three­
or
four­
dimensional
structure
of
the
response,
e.
p..
temperature
change
as
a
function
of
latitude.
longitude.
height
and
time.
Thus
a
good
march
between
modelled
and
observed
multi­
dimensional
patterns
of
climate
change
would
be
dimcult
TO
achieve
for
"causes"
other
than
those
actually
use(!
in
the
model
experiment.
Several
studies
have
compared
observed
patterns
of
temperature
change
with
modei
patterns
of
change',
from
simulations
with
changes
in
both
greenhouse
gases
and
anthropogenic
sulphate
aerosols.
These
comparisons
hare
been
made
at
the
Earth's
surface
and
in
vertical
sections
through
the
atmosphere.
While
there
are
concerns
rearding
the
.
relatively
simple
treatment
of
aerosol
effects
in
model
experiments.
a
n
d
.
the
neglect
of
other
potentially
significant
contributions
'to
the
radiative
forcing,
all
such
pattern
comparison
studies
show
significant
correspondence.
'
between
the
observations
and
model
predictions
(an
example
is
shown
in
Figure
17).
Much
of
the
model­
observed
corrcspondencc
.in
these
experi~
ncnts
occurs
at
the
largest
spatial
scales
­
for
csamplc.
temperature
differences
betwccll.
hemispheres.,
land
and
ocean;
or
the
troposphere
'and
strt~
tosphcre.
Model
.
predictions
are
more
reliable
at
these
spatial
scales
than
at
the
regional
scale.
Increasing
confidence
in
the
identification
of
a
human­
induced
effect
on
climate
comes
primarily
from
such
pattern­
based
work.
For
those
seasons
during
which
aerosol
effects
should
be
most
pronotu~
ced
the
pattern
correspondence
is
generally
higher
than
that
achieved
if
model
predictions
are
based
on
changes
in
greenhouse
gases
alone
(Figure
1
T).
As
in
the
global
mean
studies,
pattern­
oriented
detection
work
relies
on
model
estimates
of
internal
natural
variability
as
the
primary
yardstick
for
temperature
patterns
could
be
due
to
natural
causes.
Concerns
remain
regarding
the
reliability
of
this
yardstick.
..

cictlckLiLLg
b,,
ilciiicr
U
~J
S
~K
V
~U
.
c[
l;
t[
lges
111
42
I
..
60's
aws
"
­
180"
135'W
SO'W
45"
W
0"
45'E
90'E
135'E
180'

W
60's
905
t"
s
'
180"
135'W
90"
W
45'W
0'
45'E
90'E
135'E
180"
Figure
17:
Annual
mean
near­
srlrjace
air
temperature
changes
("
0
from
eqtlilibrirlm
response
experiments
uith
an
atmospheric
GCM
with
a
mixed­
layer
ocean
coupled
to
a
tropospheric
chemistry
model.
forced
mith
present­
day
atmosplreric
concentrations
of
COY
(a)
and
by
the
combined
e/
fects
of
present­
day
CO,
lecels
and
sulphw
emissions
(b).
Obserced
ternperailire
changes
from
1955P4
to
1975­
94.
­
show1
in
Figure
9.
are
qualitatirely
more
similar
to
the
changes
in
the
combined
forcing
experirnefzt
than
ir~
the
CO,
only
experiment.

arcas
o
f
q
u
a
l
i
t
a
t
i
v
e
a
g
r
e
e
m
e
n
t
b
e
t
w
e
e
n
obscrvations
and
those
model
predictions
that
either
i~
icludc
aerosol
effects
or
do
not
depend
critically
on
their
inclusion.
As
in
the
quantitative
studies.
one
m
u
s
t
b
e
c
a
u
t
i
o
u
s
i
n
a
s
s
e
s
s
i
n
g
consistency
because
the
expected
climate
change
signal
due
to
human
activities
is
still
uncertain,
and
has
changed
as
our
ability
to
model
the
climate
system
has
improved.
In
addition
to
the
surface
warming.
the
model
and
obsorved
commonalities
in
which
we
have
most
confidence
include
stratospheric
cooling.
reduction
in
diurnal
temperature
range,
sea
level
rise:
high
latitude
precipitation
increases
.and
water
vapour
and
evaporation
increase
over
tropical
oceans.
In
summary.
the
most
important
results
related
to
the
issues
of
detection
and
attribution
are:

0
The
limited
available
evidence
from
prosy
climate
indicators
suggests
that
the
20th
century
.
global
mean
temperature
is
at
least
as
ivarm
as
any
other
century
since
at
least
1400
AD.
Data
prior
to
1400
arc
too
sparse
to
allow
the
reliable
estimation
of
global
mean
temperature
(sec
Section
.C.
2).

0
Assessments
of
the
statistical
significance.
of
the
observed
global
mean
temperature
trend
over
,.

the
iast
century
have
used
a
variety
of
new
estimates
of
natural
internal
and
esternally
forced
variability.
These
are
derived
from
instrumental
data.
palaeodata,
simple
and
,
complex
climate
modeis,
a11~
siatisilci
ihbuL;
C:
3
fitted
to
observations.
Most
of
these
studies
have
detected
a
significant
change.
and
show
that
the
observed
warming
trend
is
unlikely
to
be
entirely
natural
in
origin.

43
..

­1
:
.
..
.
.
.
.
..
..
..
0
More
convincing
recent
evidence
for
the
(compounded).
For
comparison
the
IS92a
Scenario.
attribution
of
a
human
effect
on
climate.
is
neglecting
the
effect
of
aerosols,
is
equivalent
to
a
emerging
from
pattern­
based
studies,
in
which
compounded
rate
of
increase
varying
from
0.77
to
the
modelled
climate
response
to
combined
0.84%/
yr
during
the
21st
century.
forcing
by
greenhouse
gases
and
anthropogenic
The
projections
of
global
mean
temperattlre
sulphate
aerosols
is
compared
with
observed
sea
level
changes
do
not
come
directly
from
coupleci
geographical,
seasonal
and
vertical
patterns
of
atmosphere­
ocean
models.
Though
these
are
t
h
e
atmospheric
temperature
change.
These
studies
most
sophisticated
tools
available
for
making
s
h
o
w
t
h
a
t
s
u
c
h
p
a
t
t
e
r
n
c
o
r
r
e
s
p
o
n
d
e
n
c
e
s
projections
of
future
climate
change
they
are
increase
with
time,
as
one
would
expect
as
an
computationally
expensive,
making
i
t
unfeasible
to
anthropogenic
signa!
increases
in
strength.
produce
results
based
on
a
large
number
of
Furthermore,
the
probability
is
very
low
that
emission
scenarios.
In
order
to
assess
global
these
correspondences
could
occur
by
chance
as
temperature
and
sea
level
projections
for
the
fuii
a
result
of
natural
internal
variability
only.
The
range
of
Is92
emission
scenarios.
simple
upnelling
vertical
patterns
of
change
are
also
inconsistent
diffusion­
energ).
balance
models
(see
Box
2)
can
be
with
those
expected
for
s
d
r
and
volcanic
employed
to
interpolate
and
extrapolate
the
couplecl
forcing.
model
results.
These
models,
used
for
similar
tasks
in
IPCC
(1990)
and
IPCC
(1992).
are
calibrated
to
give
the
same
globally
averaged
temperature
response
as
the
coupled
atmosphere­
ocean
models.
T
h
e
c
l
i
m
a
t
e
s
i
m
u
l
a
t
i
o
n
s
h
e
r
e
are
called
projections
instead
of
predictions
to
e
q
h
a
s
i
s
e
that
they
do
not
represent
attempts
to
forecast
the
most
likely
(or
"best
estimate")
evolution
of
climate
i
n
the
future.
The
projections
are
aimed
at
estimating
and
undcrstanding
responses
of
the
climate
system
to
possible
forcing
scenarios.
­

I
0
Our
ability
to
quantify
the
human
influence
on
global
climate
is
currently
limited
because
the
expected
signal
is
still
emerging
from
the
noise
of
n
a
t
u
r
a
l
v
a
r
i
a
b
i
l
i
t
y
;
a
n
d
b
e
c
a
u
s
e
t
h
e
r
e
a
r
e
uncertainties
in
key
factors.
These
include
the
magnitude
and
patterns
of
long­
term
natural
variability
and
the
time­
evolving
pattern
of
forcing
by,
a
n
d
r
e
s
p
o
n
s
f
t
o
,
c
h
a
n
g
e
s
.
i
n
concentrations
of
gree!
house
g
a
s
e
s
a
n
d
a
e
r
o
s
o
l
s
,
a
n
d
,
land­
surface
changes.
I
Nevertheless.
the
balance
of
evidence
suggests
that
there
is
a
discernible
human
influence
on
F*
2
Projections
of
climate
change
­,

global
climate.

climate
change
emissions
of
both
grecnho__;
.......

F.
l
­Forcing
scenarios
precursors
(Section
B.
9.11
projected
global
mean
Projections
of
future
anthropogenic
climate
change
tempcrature
challges
relative
to
1990
were
depend;
amongst
other
things,
on
the
scenario
used
calculated
for
the
21st
century.
Temperature
to
force
the
'climate
model.
The
IS92
emission
projections
assuming
the
"best
estimate"
value
of
scenarios
are
used
here
for
projections
of
changes
in
climate
sensitivity,
2.5"
C.
(sce
Section
D.
2)
are
global
mean
temperature
and
sea
level.
The
IS92
shown
for
the
full
set
of
IS92
scenarios
in
Figure
18.
scenarios
include
emissions
of
both
greenhouse.
For
IS92a
the
temperature
increase
by
2100
is
2°
C.
gases
and
aerosol
precursors
(see
Section
B.
9.1)
and
Taking
account
of
the
range
in
thc
estimate
of
for
the
first
time
both
factors
have
been
taken
into
climate
sensitivity
(1.5
to
4.5'C)
and
the
full
set
of
account
in,
the
global
mean
temperature
and
sea
IS92
emission
scenarios,
the
models
project
an
level
projections
(Section
F.
2).
increase
in
global
mean
temperature
of
between
0.9
In
many
coupled
model
experiments
the
forcing
and
3.5"
c
(Figure
19).
In
all
cases
the
al'PralnP
raw
scenario
is
simplified
by
summing
the
radiative
of
warming
would
probably
be
greater
than
an)
forcings
of
all
the
trace
gescs
(co,,
CU;,
0,.
ctc.)
c:;
d
scfn
in
the
!as:
IC.
3CO
cars.
hi;:
iht:
;Cts;
ii
ztiiiiu'.:

treating
the
total
forcing
as
if
it
came
from
a
n
to
decadal
changes
would
include
considerable
"equivalent"
concentration
of
c02.
The
rate
of
natural
variabilitx.
Because
of
the
thermal
inertia
of
increase
of
"equivalent
CO,"
in
these
experiments
is
the
oceans.
global
mean
temperarure
~r
o
u
l
d
o
f
t
e
n
a
s
s
u
m
e
d
t
o
b
e
a
constant
+10/
o/
vr
c
o
n
t
i
n
u
e
t
o
.
i
n
c
r
e
a
s
e
b
e
v
o
n
d
2100
even.
if
..
..
concentrations
of
greenhouse
gases
were
stabilised
a
t
t
h
a
t
t
i
m
e
.
Only
50­
90%
of
the
eventual
temperature
changes
are
Tealised
at
the
time
of
greenhouse
gas'
stabilisation.
All
scenarios
show
substantial
climate
warming,
even
when
the.
negative
aerosol
radiative
forcing
is
accounted
for.
Although
CO2
is
the
most
important
anthropogenic
greenhouse
gas,
the
other
greenhouse
gases
contribute
significantly
(about
30%)
to
the
projected
global
warming.
To
allow
closer
comparison
with
the
projections
presented
in­
IPCC
(1990)
and
IPCC
(1992)
and
to
illustrate
the
sensitivity
of
future
global
temperature
to
changes
in
aerosol'
concentrations,
the
same
series
of
calculations
were
performed
neglecting
future
aerosol
changes,
i.
e.
aerosol
concentrations
were
held
constant
at
1990
levels.
These
lead
to
higher
projections
of
temperature
change.
Taking
account
of
the
range
in
the
estimate
of
climate
sensitivity
and
the
full
set
of
IS92
emission
scenarios,
the
models
project
an
increase
in
global
mean
temperature
of
between
0.8
and
4.5"
C.
For
IS92a,
assuming
the
"best
estimate"
of.
climate
­sensitivity.
the
temperature
increase
by
2100
is
24°
C.
For
comparison.
the
corresponding
temperature
increase
for
IS92a
presented
in
IPCC
(1992)
was
­2.
S"
C.
The
projections
in
IPCC
(1990)
were
based
OR
an
earlier
set,
of
emission
scenarios,
the
"best
estimate"
for
the
increase
in
global
temperature
by
2100
(relative
to
1990)
was
3.3"
C.

E2.2
Global
mean
sea
level
response
to
.
1592
emissionscenarios
.

Using
the
IS92
emission
scenarios.
including
gre.
enhouse
.gas
and
ae'rosol
precursors,
projected
global
mean
sea
level
increases
relative
to
1990
were
calculated
for
the
21st
century.
Sea
level
projections
assuming
the,
"best
estimate"
values
for
climate
sensitivity
and
ice
melt
are
shown
for
the
full
set
of
IS92
scenarios
in
Figure
20.
For
IS92a.
the
sea
level
rise
by
2100
is
49
cm.
For
comparison.
the
"best
estimate"
of
global
sea
level
rise
by
2100
given
in
IPCC
(1990)
was
66
cm.
Also
taking
account
of
the
ranges
in
the
estimate
of
climate
sensitivity
and
ice
melt
parameters,
and
the
full
set
of
1592
ern­
ission
scenarios,
the
models
project'an
increase
in
global
mean
sea
level
01
betxyeen
13
anu
94
cm
(Figure
21).
During
the
first
haif
of
the
nesi
century,
the
choice
of
emission
scenario
.has
relatively
little
effect
on
the
projected
sea
level
rise
due
to
the
large
thermal
inertia
of
the
ocean­
ice­
atmosphel­
e
climate
system.
but
has
increasingly
Year
Figure
18:
Projected
global
mean
surface
temperature
changes
from
1990
to
2100
for
the
full
set
of
IS92
emission
scenarios.
A
climate
sensitivity
of
2.5%
is
assumed.

..

"

20002020
­2040
2060
2080
2100
.
.
Year
Figure
19:
Projected
global
mean
surface
temperature
change
extremes
from
1990'to
2100.
The
highest
temperature
changes
assume
n
climate
sensitiuity
of
4.5%
'and
the
IS92e
emission
scenario;
the
lowest
a
climate
sensitivity
of
1.5%
a,
nd
the
IS92c
emission
scenario
and
the
mid­
range
curves
a
climate
Sensitivity
of
2.5%
and
the
IS92a
Scenario.
The
solid
curves
include
the
effect
of
changing
aerosol:
the
dashed
curves
assume
aerosol
emissions
remain
constant
at
their
1990
lereis.

'
L
45
...
...
......
..
..
Year
4
Figure
20:
Projected
global
mean
sea
level
rise
from
1990
to
..
2100
for
the
fidl
set
of
IS92
emission
scenarios.
A
climate
sensitirity
of2.5'C
and
mid­
value
ice
melt
parameters
are
assumed.

a,
u)
.­
L
40
I
c
Year
In
these
projections,
the
combined
contribLltioll
of
the
Greenland
and
Antarctic
ice
sheers
are
projected
to
be
relatively
minor
over
the
nest
century.
However,
the
possibility
of
large
chal1gej
i
l
l
the
volumes
of
these
ice
sheets
(and.
consequeiltl!.,
in
sea
level)
cannot
be
ruled
out,
although
tlIr
likelihood
is
considered
to
be
low.
Changes
in
future
sea
level
will
not
O
C
C
~I
~

uniformly
around
the
globe.
Recent
couplec\
atmosphere­
ocean
model
esperimeuts
suggest
thal
the
regional
responses
could
differ
substantially.
o\
ving
to
regional
differences
in
heating
ant!

circulation
changes.
In
addition,
geological
~I
I
C
~

geophysical
processes
cause
vertical
lancl
movements
and
thus
affect
relative
sen`
levels
011
local
and
regional
scales.
Tides.
waves
and
storm
surges
couId
be
ilffected
by
regional
climate
changes.
but
future
projections
are.
at
present,
highly
uncertain.

152.3
Temperature
and
sea
level
projections
compared
with
/K
C
(7990)
The
global
average
tempcraturc!
aiid
sea
level
projections
presented
here
for
1990
to
2100.
both
e
s
c
l
u
d
i
n
g
a
n
d
i
n
c
l
u
d
i
n
g
c
h
a
n
g
i
n
g
a
e
r
o
s
o
l
emissions,
are
lower
than
the
corresponding
projections
presented
in
IPCC
11990).
Taking
into
account
the
negative
radiative
forcing
of
aerosols
reduces
projections
of
temperature
and
sca
level
rise.
T
~O
S
C
projections
which
e
s
c
l
d
e
the
ct't'ectof
changing
aerosol
emissions
are
lonw
than
IPCC
(1990)
for
a
number
of
reasons,
mainly:

0
The
revised
(IS921
cmission
scenarios
have
been
u
s
e
d
f
o
r
all
grccnhousc
gases.
This
is
particularly
important
for
CO,
a
n
d
CFCs.

Revised
treatment
of
thc
carbon
cvcle.
The
Figure
21:
Projected
global
mean
sea
leuel
rise
extremes
from
1390
to
2100.
The
highest
sea
level
rise
curue
assumes
carbon
cycle
rnoclcl
used
to
calculate
future
a
climnte
semiticity
of
4.5%.
high
ice
melt
parameters
and
temperature
and
sea
level
rise
in
IPCC
(19901
the
IS92e
emission
scenario:
the
lowest
a
climate
sensitivit.
v
and
II'CC
(1992)
did
not
incorporate
the
effect
of
of
1.5%.
low
ice
melt
parameters
and
the
IS9Zc
emission
carbon
uptake
.
through
C
0
2
fertilisation.
scenario
nnd
the
middle
curues
a
climate
sensitivity
of2.5.
c.
,resulting
in
highkr
futurc
CO,
concentrations
for
mid­
rnlrte
ice
melt
parameters
and
the
IS92a
Scenario.
given
emissions
in
IPCC
(1990).

larger
effects
in
the
latter
part
of
the
nest
century.
In
addition.
because
of
the
thermal
inertia
of
the
..
oceans,
sea
level
would
continue
to
rise
for
many
centuries
bcyo1:
cl
2100
even
if
concrntrations
of
greenhouse
gases
were
stabilised
at
that
time.
The
projected
rise
in
sea
level
is
primarily
due
to
thermal
espansion
as
the
ocean
Ivaters
tvarrn.
but
also
due
to
increased
melting
of
glaciers.
0
The
inclusion
of
aerosol
effects
in
the
pre­
1990
radiative
forcing
history.
The
estimated.
historical
thanncs
of
radintivo
fnrcinr
up
to
1990.
used
in
this
report
for
global
mean
.a
component
due
to
aerosols.
This
particularly
affects
projections
of
sea
level
rise.
tvhich
are
strongly
influenced
by
the
history
of
radiative
forcing
ocer
the
last
century.
ternpcrature
?.:
id
S
E
~
I
c
\~;
~FU;
L~
'L;,,;~>.
iii<!:~<!;<
0
Revised
(and
more
realistic)
parameters
in
the
simple
upwelling
diffusion­
energy
balance
c
l
i
m
a
t
e
m
o
d
e
l
.
­
4
0
The
inclusion
in
the
model
of
spatial
variations
in
the
climate
sensitivity
and
the
effect
of
changing
strength
,of
t
h
e
t
h
e
r
m
o
h
a
l
i
n
e
circulation,
to
accord
with
coupled
atmosphere­
ocean
general
circulation
models.

@
Thc
usc
of
improved
models
for
the
ice
melt
component
of
sea
level
rise.

F.
3
Spatial
patterns
of
projected
climate
change
Although
in
global
mean
terms,
the
effect
of
including
aerosols
is
to
reduce
the
projected
warming
(scc
Section
F.
2).
it
can
be
rnislcading
to
consider
only
the
global
mean
surface
temperature.
which
does
not
give
an
effective
indication
of
climate
.change
at
smaller
spatial
scalcs.
Because
aerosols
arc
short­
lived.
they
are
uncvcnly
distributed
across
the
globe,
being
concentrated
ncar
regions
where
they
are
emitted.
As
a
result.
thc
spatial
pattern
of
aerosol
forcing
is
ve&
different
'to
that
produced
by
thc
long­
lived
w
+m
i
s
e
d
g
r
e
c
n
h
o
u
s
e
g
a
s
e
s
2
n
d
.
w
h
c
n
simulations
that
include
the
effects
of
both
aerosols
and
co2,
neither
of
which
have
yet
been
thoroughly
analysed.
LVe
have
concentrated
on
those
changes
which
show
most
consistency
between
models,
and
for
which
plausible
physical
mechanisms
have
been
identified.
.

Temperature
and
Precipitation
All
model
simulations.
whether
they
are
forced
with
increased
concentrations
of
greenhouse
gases
and
aerosols,
or
with
increased
greenhouse
.
gas
concentrations
alone,
show
the
following
features:

0
generally
greater
surface
warming
of
the
land
than
of
the
oceans
in
winter,
as
in
equilibrium
simulations
(Figures
22
and
231;

*.
a
minimum
warming
around
Antarctica
and
in
&the
northern
North
Atlantic
which
is
associated
with
deep
oceanic
mixing
in
those
areas:

0
maximum
warming
in
high
northern
latitudes
in
late
autumn
and
winter
associated
with
reduced
sea
ice
and
snow
cover:

0
little
warming
over
the
'Arctic
in
summer:

little
seasonal
variation.
of
the
warming
in
low
­
latitudes
or
over
the
southern
circumpolar
ocean:
considering
pattcrns
of
climntc?
change.
thcir
cooling
,
'
..
0
a
reduction
in
diurnal
temperature
range
ober
effcct
is
not
a
sirllplc
offsct
to
the
warming
effcct
of
greenhouse
gases.
as
might
be
implied
from
the
global
mcarresults.
Aerosols
are
likcly
to
have
a
significant
offcct
on
future
regional
climntc
changc.
,

Confidcncc
is
highcr
in
hcmisphcric
to
continental
scalc
projnctiorts
o
f
climate
changc
(Section
F.
3.1)
than
at
regional
scalcs
(Section
F.
3.2).
whcre
confidcncc
remains
low.

E3.1
Continental
scale
patterns
I
n
IPCC
(1990).
estimrttes
of
the
patterns
of
future
climntc
changc
were
prescnted.
the
most
robust
of
which
relatcd
.to
continental
and
larger
spatial
scalcs.
The
results
xere
based
on
CCM
experiments
.which
included
the
effect
of
greenhouse
gases,
but
did
not
take
into
account
the
effects
of
aerosols.
The
following
provides
some
details
of
the
changcs
on
continental
scales
in
experiments
with
'greenhouse
gases
alone
(generally
represented
by
a
,
l'ju,
sr
ir,
c:
erh;:
i
n
U?,)
and
increases
in
Freenhouse
gas
and
aerosol
conc.
entrations
(using
aerosol
concentration
derived
from
the
IS92a
Scenario).
It
is
important
to
realise
that,
in
contrast
to
the
many
model
results
with
COz
alone,
there
are
only
two
recent
coupled
atmosphere­
ocean
model
,
land
in
most
seasons
and
most
regions;

a
n
enhanced
global
mean
hydrological
cycle:

i
incremed
precipitation
in
high
latitudes
in
.
winter.
,

Including
the
effects
of
aerosols
in
simulations
of
future
climate
leads
to
a
somewhat
reduced
surface
warming,
mainly
in
middle
latitudes
of
the
Northern
Hemisphere.
The
maximum
winter
warming
in
high
northern
latitudes
is
less
extensive
(compare
_Figures
22
and
23).
Hon.
ever.
adding
the
cooling
effect
of
aerosols
is
not
a
simple
offset'
t
o
.
t
h
e
w
a
r
m
i
n
g
effect
of
greenhouse
gases,
but.
significantly
affects
some
of
the
continental
scale
patterns
of
climate
change..
This
is
most
noticeable
in
summer
where
the
cooling
due
to
aerosols
tends
to
weaken
monsoon
circulations.
For
esample.
when
the
effects
of
both
greenhouse
gases
and
aerosols
are
included,
Asian
'summer
monsuon
m
i
d
d
l
L!
C:
XX~:
~.+~F
R
S
i
n
earlier
simulations­
with
'only'
the
effect
of
'.

greenhouse
gases
represented,
Asian
summer
monsoon
rainfall
increased.
Conversely.
'the
addition
of
aerosol
effects
leads
to
a
n
i
n
c
r
e
a
s
e
i
n
1
\
x.­

4T
Figure
22;
The
patterrl
of
surface
temperature
change
projected
at
the
time
of
CO,
doubiiny
frorll
a
transient
corrpled
model
e.
rperiment.

180"
90'W
0'
90'E
,
180'

­6
­4
­2
0
2
4
6
3
Figure
23:
The
pntterrl
oJsurjiace
temperature
change
projrcted
by
a
transient
corlpled
rnodrl
at
the
time
of
CO,
donbliny
rr'tm
both
CO,
and
nerosol
­
concentration
increases
are
taken
into
account.

­6
­4
­2
2
'
4
­6
Precipitation
over
southern'
Europe,
whereas
decreases
are
found
in
simulations
with
greenhouse
gases
only.
These
changes
will
be
sensitive
to
the
aerosol
scenario
used,
and
the
details
of
the
parametrization
of
the
radiative
effects
of
aerosol.
Other
forcings.
including
that
due
to
increases
in
tropospheric
ozone,
soot
and
the
indirect
effect
of
sulphate
aerosols
have
been
neglected
and
could
influence
these
results.
In
general,
regional
projections
are
also
sensitive
to
model
resolution
and
are
affected
by
large
natural
variability.
Hence
confidence
in
regional
projections
remains
low.
With
increases
in
C02
only.
two
coupled
atmosphere­
ocean
models
show
a
pattern
of
SST
(sea
surface
temperature)
chanp,
precipitation
change
and
anomalies
in
kind
and
ocean
currents
that
resemble
the
warm
phase
of
ENSO,
a
s
y
e
l
l
as
the
obscrw!
decadal
t
i
n
­s
c
a
l
z
SST
anonmlics
of
the
1980s
and
early
1990s.
This
is
characterised
by
a
reduction
of
the.
east­
west
SST
gradient
in
the
tropica1,
Pacific.
though
the
magnitude
of
this
effect
varies
among
models.
Soil
moisture
Although
there
is
less
confidence
in
simulated
changes
in
soil
moisture
than
in
those
of
temperature,
some
of
the
'results
concerning
soil
moisture
are
dictated
'more
by
changes
in
precipitation
and
evaporation
than
by
the
detailed
response
.of
the
surface
scheme
of
the
climate
model.
All
model
.simulations,
i
h
e
t
h
e
r
they
are
forced
with
increased
concentrations
of
greenhouse
gases
and'
aerosols.
or
with
increased
greenhouse
gas
concentrations
alone.
produce
predominantly
increased
soil
moisture
in
high
northern
latitucles
in
winter.
Over
the
northern
continents
in
summer.
the
changes
in
soil
moisture
are
sensitive
to
the
inclusion
of
aerosol
effects.
.
,

Oceancirculation
'
.

In
resp0:
ise
io
iiicrcnsiIlg
grceniiuuse
gases,
I
I
I
U
>L
models
show
a
decrease
in
the
strength
of
the
northern
North
Atlantic
oceanic
circulation
further
reducing
the
strensh
of
the
warming
around
the
North
Atlantic.
The
increase
in
precipitation
in
high
latitudes
decreases
the
surface
salinity,
inhibiting
0
Land­
use
changes
are
also
believed
to
have
a
the
sinking
of
water
at
high
latitude,
which
drives
significant
impact
on
t
e
m
p
e
r
a
t
u
r
e
a
n
d
t
h
i
s
c
i
r
c
u
l
a
t
i
o
n
.
­
precipitation
changes,
especially
in
the
tropics
and
subtropics.
Climate
model
experiments
have
E3.2
Regional
scale
patterns
­­
shown
the
likelihood
of
substantial
local
climate
Estimation
of
the
potential
impacts
of
climate
change
associated
with
deforestation
in
the
change
on
human
infrastructure
and
natural
Amazon,
or
desertification
in
the
Sahel.
Changes
ecosystems
requires
projections
of
future
climate
in
land­
use
on
small
scales
which
cannot
be
foreseen
are
expected
to
continue
to
influence
regional
climate.
or
continental
means.
Since
IPCC
(1990).
a
greater
appreciation
has
Because
of
these
problems,
no
information
on
been
developed
of
the
uncertainties
in
making
future
regional
climate
change
is
presented
here.
projections
at
the
regional
scale.
There
are
several
However.
this
situation
is
espected
to
in1pror.
e
in
the
difficulties:
future
as
a
result
,of:

0
The
global
climate
models
used
for
future
0
more
coupled
atmosphere­
ocean
model
projections
are
run
at
fairly
coarse
resolution
Aperirnents
with
aerosol
effects
included;
and
do
not
adequately
depict
many
geographic
features
'
(such
as
coastlines.
lakes
and
m
o
u
n
t
a
i
n
s
).
s
u
r
f
a
c
e
v
e
g
e
t
a
t
i
o
n
,
a
n
d
t
h
e
interactions
betxveen
the
atmosphere
with
the
surface
which
become
more
important
on
0
more
refined
scenarios
for
.aerosols
and
other
regional
scales.
Considerable
spread
esists
among
model
projections
on
the
regional
scale
even
when
climate
modcl
espcrimcnts
are
E3.3
Changes
in
variability
and
extremes
driven
by
the
same
future
radiative
forcing
Small
changes
in
the
mean
climate
or
'climate
tariability
can
produce
relatively
large
changes
in
the
frequency
of
cstrcrnc
events
(defined
as
events
where
a
certain
threshold
is
surpasscdl:
it
small
change
in
the
variability
has
a
stronger
effect
than
a
similar
change
in
the
mean.
improvements
in
models,
both
from
increased
resolution
and
improved
representation
of
small­
scale
processes:

There
is
much
more
natural
variation
in
local
c
l
i
m
a
t
e
t
h
a
n
in
cliniatc
averaged
over
continental
or
larger
scales.
This
variation
arises
interactions
benveen
the
atmosphere
and
the.
Temperature
oceans
(such
as
EXSO).
and
fro111
variations
in
A
generill
warming
tcrlds
to
lead
to
a
n
inrrp;
lsc
in^
Soil
moisture.
Sea
ice.
and
other
COmpOnentS
of
high
tempcr;
ltllrc
events
allcl
a
decrease
the
climate
system.
Series
or
ensembles
Of
model
in
lolv
temperatures
(e.
g.,
frost
days).
"­

predictions
started
from
different
initial
.
from
locally
generated
variability
from
storms.
.

.
superimposed
variability
to
be
determined.

8
Because
of
their
uneven
spatial
distribution.

1
human
induced
tropospheric
aerosols
arc
likely
to^
greatly
influence
future
regional
climate
change.
At
present.
howver.
there
are
very
few
projections
of
climate
change
with
coupled
atmosphere­
ocean
models
(the
type
of
modcl
that
gives
more
reliable
information
on
the
effects
of
aeroso1s:
Those
that
have
been
run
.
gas
concentrations.
In
some,
areas
a
numb&
of
simulations
show
there
is
also
an
increase
in
the
probability
of
dry
days
and
the
length
of
dry
spells
(consecutive
days
without
precipitation).
Wllere
mean
precipitation
decreases,
the
likelihood
of
drought
increases.
Xew
results
reinforce
the
view
!­::?.;­!
n$
r~.!
c;:
r!
n
translates
into
prospects
for
more
severe
droughts
and/
or
floods
in­
some
places
and
:c;::~.:>.!
T::.!.)
lq:
f,
irh
inrl~
qrip
the
radiative
aerosol
effects:
Year
Figure
21:
The
gloilal
mean
surface
temperature
response
to
the
CO,
CoIrcentration
pathuays
leading
to
stabilisation
at
450
(dashed
curves)
and
650
(solid
crrrces)
pprnu
(see
Figure
7a)
for
a
climate
sensiticily
of
1.3.
2.5
and
4.5%.
The
changes
shown
are
those
nrising
from
CO,
increases
alone.
The
date
of
concentration
stabilisation
is
indicated
by
the
dot.
Calculations
assume
the
"obserued"%
istory
of
forcing
to
1930,
including
aerosol
efleects
and
then
C02
ronwntrotion
increases
only
beyond
1990.

350
300
250
Y
6
a,
F
200
m
­c
0
p
150
a,
m
­
­

c%
100
50
0
2.01
Year
Figrtre
25:
The
global'mean
sea
level
response
to
the
CO,
concentration
pothruays
leading
to
stabilisntion
at
450
(dashed
C
i
l
t
'
C
L
'
s
/
c
t
r
i
i
LS;
i
iauiiu'
cwcrs)
p
p
/m
isre
i;
gi'r<
i
u
j
j
i
r
ti
c
i
i
m
(m
sensitiritg
of
1.5.
2.5
and
4.5%.
The
changes
s
h
o
m
are
those
arisiny
frour
CO,
irrcrenses
alone.
The
date
of
concentration
stnbi[
isation
is
indicated
by
the
dot.
Cnlculafiorls
assunze
the
%bsersed"
lrisrory
of
forcing
to
1990,
including
aerosol
eflects
and
then
CO2
com­
eutrution
increases
only
beyond
1990.
Mid­
latitude
storms
In
the
felv
analyses
available,
there
is
little
agreement
between
models
on
the
changes
in
storminess
that
might
occur
in
a
warmer
tvorlcl.
Conclusions
regarding
estreme
storm
events
are
'

obviously
even
more
uncertain.

Hurricanes/
Tropical
cyclones
The
formation
of
tropical
cyclones
depends
not
o!
ll!.
on
sea
surface
temperature
(SST).
but
also
011
a
number
of
amospheric
factors.
Although
some
models
non.
represent
tropical
s
t
o
m
s
with
so111e
realism
for
present
day
climate,
thc
state
of
rile
science
does
not
allow
assessment
of
future
changes.

El
Nifio­
Southern
Oscillation
Several
global
coupled
nlodels
indicatc
that
the
ENSO­
likc­
SST
variability
thcy
simulatc
continues
with
increased
CO,.
Associated
with
the
mean
increase
of
tropical
SSTs
as
a
result
of
increased
greenhouse
gzs
conccntrations.
there
could
be
enhanced
.precipitation
variability
gssociatccl
Lcith
ENS0
evcnts
in
the
increased
COz
climate.
especially
over
rhc
tropical
continents.

F.
4
Effects
of
stabilising
greenhouse
gas
concentrations
Possiblc
global
temperature
and
sca
Icvrl
rcsponse
to
the
scenarios
for
s$
lbilising
conccntrations
discusscd
i
n
Section
R.
9.2
wcrc
calcuiatod
with
rhe­
same
upndling
diffusion­
cnergy
balance
model
used
for
the
rcstrlts
in
Sections
F.
Z.
1
and
F.
2.2.
.
,

.For
cach
of
the
pathways
lcacling
to
stabilisntion.
the
climate
system
shows
consiclcrablc
warming
d
u
r
i
n
g
t
h
e
21st
century.
Figure
24
shoivs
ternpcrature
increases
for
thc
cases
which
stabilise
at
concentrations
of
650
and
450
ppmv
for
different
clinlatc
sensirivitics.
Stabilisation
of
the
concentration
does
not
lead
to
an
imrnediate
stabilisation
of
rhe
global
mean
temperature.
The
global
nlean
temperature
is
seen
to
continue
rising
for
hundreds
of\­
ears
after
thc
concentrations
have
stabiiiscd
in
Figure
24
due
to
long
time­
scales
in
the
ocean.
As
sh0u.
n
in
Figure
25.
the
long­
term
sea
level
i'iaa
"C
U
l
l
l
l
l
l
l
l
l
l
.C
,,i
I:,
cLal1
111urs
pL'u"
ull11~~
u.
3
e
c
l
level
continues
to
rise.
at
only
a
slowly
dcclininr
rate,
for
many
centuries
after
greenhouse
gas
ConcentrationS
and
temperatures
ha5.
e
stnbiiised.

.
..
F.
5
The
possibility
of
surprises
Unexpected
external
influences.
such
as
volcanic
,
eruptions,
can
lead
to
unexpected
and
relatively
sudden
shifts
in
the
climatic
.state.
Also,
as
the
response
of
the
climate
system
to
various
forcings
can
be
non­
linear.
its
response
to
gradual
forcing
changes
may
b
e
quite
irregular.
Abrupt
and
significant
changcs
in
the
atmospheric
circulation
involving
the
Nor:
h
Pacific
lvhich
began
about
1976
were
described
i
n
I
K
C
(1990).
.A
re.
lated
esample
is
the
apparent
fluctuation
in
the
recent
behaviour
of
ENSO.
with
warm
conditions
prevailing
since
1989.
a
pattern
which
112s
been
unusual
compared
to
previous
ENSO
bclhnviour.
Another
esample
is
the
possibility
that
the
LVest
Antarctic
ice
shect
might
"surge".
causing
a
rapid
rise
in
sea
level.
The
current
lack
of
knowledge
regarding
the
spwilic
circumstances
under
which
this
might
occur.
cirhcr
in
total
or
in
part.
limits
the
ability
to
quantify
this
risk.
Nonethelcss.
the
likelihood
of
a
major
sea
level
rise
by
the
year
2
100
due
to
thc
collapse
of
the
West
Antarctic
icc
sheet
is
considcrcd
low.
In
tht:
occans
tho
meridional
overturning
might
Lvcakcn
in
a
futurc
climatc.
This
overturning
(tho
thcrmohalinc
circnlntion)
is
driven
in
part
by
dcop
convection
in
the
northern
North
Atlantic
Ocean
and
kccps
the
northern
Sorth
Atlilntic
Occan
several
clcgrcc?
s
~vrnrmcr
than
it
would
othorwisc
be.
Both
tho
study
uf
palacoclimate'
from
scclimcnt
records
and
ice
CDITS
anclmoclclling
studies
with
couplod
climate
rnivcEcls
and
ocean
GCbls
can
be
interpreted
to
suggest
that
the
ocean
circulation
has
been
very
different
in
the
past.
Both
in
these
observations
and
in
the
ocean
models.
transitions
between
different
types
of
circulation
seem
to
occur
on
a
time­
scale
of
a
few
decades,
so
relatively
sudden
changes
in
the
regional
(Sorth
Atlantic,
Lt'estern
Europe)
climate
could
occur,
presumably
mainly
in
response
to
precipitation
and
runoff
changes
gvhich
alter
the
salinity.
and
thus
the
density.
of
the
upper
layers
of
the
Sorth
Atlantic.
LVhether
or
not
such
it
suclden
change
can
actually
be
realisecl
in
response
to
global
warming
and
how
strong
a
perturbation
is
required
to
cause
a
transition
bet!
veen
types
of
circulation
are
still
the
subject
of
much
debate.
In
terrestrial
ecological
systems.
there
are
Jhresholds
in
the
sustained
temperature
and
water
availability
at
which
one
biological
population
is
replaced
by
another.
Sonic
replacement.
e.
g.,
in
tree
species,
is
slow
whilc
some.
e
g
.
in
micro­
organisms
is
rapid.
Minimum
temperatures
exist
for
thc
survival
of
organisms
in
winter.
and
the
populations
of
such
organisms
may
move
polclvards
as
the
climntc
and
especially
night­
time
temperatures
warm.
If
the
transitions
are
not
orderly.
sudclen
shifts
in
ccosystcm
functioning
will
occur.
These
may
have
impacts
of
direct
human
rclevancc
(as
cliscusscd
­in
IPCC
\V
G
I
I
(1995))
but
may
also
havc
surprising
impacts
on
climate
via
effects
on
albcdd,
acrosol
forcing.
the
hydrological
c­
dc.
cvapotnu1spir;
ttion.
C02
rclcasc
and
methane
cycling.
for
csamplo
(see
Sections
11.1
and
D.
2).
G.
Advancing
our
Understanding
An
important
long­
term
goal
is
the
accurate
projection
of
regional
climate
change,
so
that
­
potential
impacts
can
he
adequately
assessed.
Progress
towards
this
objective
depends
on
determining
the
likely
global
magnitude
and
rate
of
human­
induced
climate
change.
including
sea
level
change.
as
well
as
the
regional
expressions
of
these
quantities.
The
detection
and
attribution
of
human­
induced
climate
change
is
also
most
important.
To
achieve
these
objectives
requires
systemtic
and
sustained
global
observations
of
relevant
variables.
as
well
as
requiring
the
effective
co­
operaiion
and
participation
of
.many
nations.
The
most
urgent.
scientific
problems
requiring
attention
concern:

(i)
t
h
e
rate
and
magnitudegf
climate
change
and
sea
level
rise:

0
the
factors
controlling
the
distribution
o
l
clouds
and
their
radiative
characteristics;
'

0
the
hydrological
cycle,
including
precipitation.
evaporation
and
runoff;

0
the
distribution
and
time
evolution
of
ozone
and
aerosols
and
their
radiative
characteristics:
..
0
the
response
'of
terrestrial
and
marinc
systems
to
.
climate
change
and
their
positive
and,
negative
fccdbacks;

t
h
e
r
e
s
p
o
n
s
e
o
f
'
ice
sheets
anci
glaciers
to
climate:

tho
influence
of
human
activities
on
cmissions:

the
coupling
between
the
atmosphere
and
ocean,
and
ocean
circulation;

t
h
e
f
a
c
t
o
r
s
c
o
n
t
r
o
l
l
i
n
g
t
h
e
a
t
m
o
s
p
h
e
r
i
c
concentrations
of
carbon
dioxide
a
n
d
.
o
t
h
e
r
greenhouse
gases:
(i
i
)
detection
and
attribution
of
climate
change:

0
systematic
observations
of
key
variables.
and
development
of
model
diagnostics
relating
to
climate
change:

pataeoclirnatic
time­
series
to
describe
natura­]
variability
of
the
climate
system:
0
relevant
p
r
"r
y
data
to
construct
arid
(i
i
i
)
regional
patterns
of
climate
change:

land­
surface
processes
and
their
link
to
atmospheric
processes;

@
coupling
of
scales
between
global
climate
modeis
and
regional
and
smaller
scale
models;

0
simulations
with
higher
resolution
climate
models.

The
research
activities
for
each
objective
are
strongly
interconnected.
Such
research
is
and
needs
to
be
conducted
by
individual
investigators
in
a
variety
of
institutions.
.as
well
as
by
co­
ordinated
international
efforts
which
pool
natioEal
resources
and
talents
in
order
to
more
efficiently
engage
in
large­
scale
integrated
field
a
n
d
m
o
d
e
l
l
i
n
g
programmes
to
ndvancc
our
understanding.

..
.
..
.
..
.
..
Glossary
Aerosols
­

Climate
change
(FCCC
usage)

Climate
change
(IPCC
usage)

Climate
sensitivity
Diurnal
temperature
rangc
Equilibrium
climate
experiment
Equivalent
C02
Evapotranspiration
Greenhouse
gas
Airborne
particles.
The
term
has
also
come
to
be
associated,
erroneously,
with
the.
propellant
used
in.
"aerosol
sprays'.

.A
change
of
climate
which
is
attributed
directly
or
indirectly
to
human
activity
t
h
a
t
alters
the
composition
of
the
global
atmosphere
ancl
which
is
in
addition
to
natural
climate
variability
observed
over
comparable
time
periods.

Climate
change
as
referred
to
i::
the
observational
record
of
climate
occurs
because
of
internal
changes
within
the
climate
system
or
in
the
interaction
betlveen
its
components,
or
because
of
changes
in
esternal
forcing
either
for
natural
reasons
or
because
of
human
activities.
It
is
generally
not
possible
clearly
to
make
attribution
between
these
causes.
Projections
of
future
climate
change
reported
by
IPCC
g
e
d
a
l
l
y
consider
only
the
influence
on
climate
of
anthropogenic
increases
in
greenhouse
gases
and
other
human­
related
factors.

InlpCC
reports,
climate
sensitivity
usually
refers
to
the
long­
term
(equilibrium)
change
in
global
m
a
n
surface
temperature
following
a
doubling
of
atmospheric
C02
(or
equivalent
C021
concentration.
More
generally,
it
refers
to
the
equilibrium
change
in
surface
air
.
­
temperature
following
a
unit
change
i
n
radiative
forcing
("
C/
tVm­~).

The
difference
between
masimuln
and
minimuni.
tcmpcraturo
oycr
a
period
of
21
hours.

­411
cspcrimcnt
where
a
step
change
is
applied
to
the
forcing
of
a
climate
model
and
the
model
is
then
allowed
to
redch
a
new
equilibrium.
Such
esperimcnts
proviclc
information
on
thc
difference
between
the
initial
and
final
states
of
the
model.
bu­
t
not
on
the
time­
dependent
response.

The
concentration
of
CO,
that
would
cause
'the
same
amount
of
,

radiative
forcing
as
the
given
misture
ofCO,
and
othcr
grct:
nhousc
gases.
..

The
combined
process
of
evaporation
from
the
Earth's
surface
and
transpiration
from
vegetation.

A
gas
that
absorbs
radiation
at
specific
wavelengths
within
the
spectrum
of
radiation
(infrared
radiation)
emitted
by
the
Earth's
surface
and
by
clouds.
The
gas
in
turn
emits
infrared
radiation
from
a
level
where
the
temperature
is
colder
than
the
surface.
Tilt:
net
effect
is
a
local
trapping
of
part
o
i
the
absorbed
rnergy
and
a
.

tendency
to
warm
the
planetary
surface.
LVater
vapour
(H,
O),
carbon
dioxide
(CO,).
nitrous
oside
(S20),
methane
(CIf,)
and
ozone
(0,)
are'the
primary
greenhouse
gases
in
the
Earth's
atmosphere.

5
3
..
.
,..
.
.
..
CLIMATE
CHANC
­.
795
­
The
Science
of
Climate
Change
,I'
~

Ice­
cap
A
dome­
shaped
glacier
usually
covering
a
highland
near
a
!yarer
divide.

­
Ice
sheet
A
g
l
a
c
i
e
r
m
o
r
e
t
h
a
n
50,000
Lrnz
in
a
r
e
a
f
o
n
n
i
n
g
a
continuous
covey
Over
a
land
surface
or
resting
on
a
continental
shelf.
.

Radiative
forcing
A
simple
measure
of
the
importance
of
a
potential
climate
change
mechanism.
Radiative
forcing
is
the
perturbation
to
the
e
n
e
y
s
­
balance
of
the
Earth­
atmosphere
system
(i
n
\\
'm­
')
follo\
ving.
for
esample.
a
change
in
the
concentration
of
carbon
dioside
or
a
change
in
the
output
of
the
Sun:
the
climare
system
responds
to
the
racliative
forcing
so
a
s
to
re­
establish
the
energy
balance.
A
p0sirii.
e
radiative
forcing
tends
to
warm
the
surface
and
a
negative
radiati\­
e
forcing
tends
to
cool
the
surface.
The
radiative
forcing
is
normally
quoted
as
a
global
and
annual
mean
value.
.4
more
precise
definition
of
radiative
forcing.
as
usecl
in
IPCC
reports.
is
the
perturbation
of
,the
energy
balance
of
the
surface­
troposphere
system.
after
allowing
for
the
stratosphere
to
re­
adjust
to
a
stale
of
global
mean
radiative
equilibrium
(see
Chapter
4
of
IPCC
(1994)).
Sometimcs
called
"climate
forcing".

Continental:
10
­
100
million
square
kilometrt!
s
(kmz)
Regional:
100
thousand
­
10
million
k
m
l
,

Local:
less
than
100
thousand
km?
­
Spatial
scales
3
Soil
rnoislure
­
Wltcr
storod
in
or
a
t
the
continclital
surfwe
and
available
for
ctapor:
ition.
I
n
II'CC
.
(1990)
a
single
storc
(or
"buc:
kct")
\vas
comnionly
uscd,
in
climate
~;
odcls.
Toclay's
models
which
incorporafr!
canopy
and
soil
proccsscs
vicw
soil
moisture
a
s
t
h
e
amount
lwld
i
n
cscoss
of
plant
"wilting
point".

Slralosp11cre
Tho
highly
s
t
r
a
t
i
f
i
e
d
a
n
d
s
t
a
b
l
c
region
o
f
tho
a
t
n
w
s
p
h
c
r
e
a
b
o
v
e
t
h
e
troposphcrc
(qr.
1
extcnding
from
&ut
10
km
to
about
50
km.

Thermol~
alinc
circulation
h
r
g
o
scale
density­
driven
circulation
i
n
the
oceans.
driven
b>­
diffcrencc:
s
in
temperature
and
salinity.

Transient
clirnatc
experiment
An
analysis
of
the
time­
depenclent
response
of
a
climate
model
to
a
time­
varying
change
of
forcing.

Troposphere
T
h
e
l
o
w
s
t
p
a
r
t
o
f
t
h
e
a
t
m
o
s
p
h
e
r
e
from
the
surface
to
about
10
km
in
altitudc
in
mid­
latitudes
[ranging
from
9
kn1
i
n
high
latitudes
to
16
km
in
the
tropics
on
average)
where.
cloucls
and
"weather"
phenomena
occur.
The
troposphere
is
cieiineti
as
he
region
b
b
i
w
i
tempcraturw
gencrally
decrease
[virh
i
l
p
i
y
l
r
.
.x
/'

I
.

References
IPCC,
(IntergoTernDen'tal
Panel
on'climate
Change)
1990:
Climate
Change:
The
IPCC
Scientific
Assessment.
J.
T.
Houghton,
G.
J.
Jenkins
and
J.
J..
Ephraums
(eds.),
Cambric&
Urliversity
Press,
Cambridge,
Tu'#,
365
pp.

IPCC,
1992:
Climute
Chctnge
1992:
The
Supplementary
Report
to
the
IPCC
Scientific
Assessment,
J.
T.
Houghton,
B.
A.
Callander
and
S.
K.
Varney
(eds.),
Cambridge
University
Press,
Cambridge,
UK.
198
pp.

IPCC,
1994:
Climate
Change
1994:
Radiative
Forcing
of
Climate
Change
and
an
EvalLlation
of
the
IPCC
7.932
Elnission
Scenarios,
J.
T.
Houghton,
L.
G.
Meira
Filho,
J.

Bruce,
Iioesung
Lee,
B.
A.
Callander,
E.
Haites,
N.
Harris
and
K.
Maskell
(eds.),
Cambridge
University
Press,
C&
bridge,
UK,
339
PP.
3
IPCC
WGII,
1995:
Climate
Change
1995
­
Impacts.
Adaptations
clnd
Mitigations
oj'

Climatt,
Change:
Scientific­
Technical
Analyses:
Contribrltion
of
Working
Group
11
10
the
Second
Assessment
Report
of
the
Intergovernmental
Panel
o~<
Climate
Change,
R.
T.
Watson,
M.
C.
Zinyowcra
and
R.
H.
Moss
(eds.),
Cambridge
University
Press,
New
York,
USA..
'
­

IPCC
WGI,
1995:
Climate
Change
1995,
­
The.
Science
of
Climate
Change:
Conlrihlion
of
Working
Group
I
to
the
SecondAssessment
Report
of
the
Inter~
ooerrznlentctl
Panel
on
Clilnnte
Change.
J.
T.
Houghton,
L.
G.
Meira
Filho,
B.
A.
Callander,
N.
Ilarris,
A.
Kattcnberg
and
K.
Maskell
(eds.),
Cambridge
University
Press,
Cambridge,
UK.

f
Conference
on
Human
Health
and
­
Global
Climate
Change
Summary
of
the
Proceedings
NationalScience
Technology
Council
and
the
'Institute
of
Medicinemational
Academy
of
Sciences
Written
by
Paul
B.
Phelps­
for
the
Institute
of
Medicine
Valerie
Setlow
and
Andrew
Pope,
Editors
NATIONAL
ACADEMY
PRESS
'Washmgton,
D.
C.
1996
..

\
"
/
~

­_
//
I..

NATIONl
ACADEMY
PRESS
2101
Constitutioa.
Avenue,
N.
W.
*
Washington,
DC
20418
NOTICE:
The
conference
that
is
the
subject
of
this
summary
was
approved
by
the
Govemi
Board
of
the
National
Research
Council,
whose
members
are
drawn
fiom
the
councils
of
the
Natior
Academy
of
Sciences,
the
National
Academy
of
Engineering,
and
the
Institute
of
Medicine.
This
report
has
been
reviewed
by
a
group
other
than
the
authors
accordins
to
proredm
approved
by
a
Report
Revie;
r­
Committee
consisting
of
members
of
t
k
Xziions:
Ai;
t&
iiiY
o
i
Science
tile
Wationai
Academy
of
Engineering,
and
the
Institute
of
Medicine.
The
Institute
of
Medicine
was
chartered
in
1970
by
the
National
Academy
of
Sciences
to
enli
distinguished
members
of
the
appropriate
professions
in
the
examination
of
policy
matters
pertaining
t
the
health
of
the
public,
In
this,
the
Institute
acts
under
both
the
Academy's
1863
congressional
chartt
responsibility
to
be
an
adviser
tothefederal
government
and
its
own
initiative,
to
identify
issues
c
medical
care,
research,
and
education.
Dr.
Kenneth
I.
Shine
is
president
of
the
Institute
of
Medicine,
This
summary
was
prepared
by
Paul
Phelps
for
the
Institute
of
Medicine.
It
summarizes
th
presentations
and
discussions
that
occurred
during
a
2­
day
conference
(September
11­
12,
1995)
that
wa
organized
and
conducted
in
a
collaborative
effort
between
the
Institute
of
Medicine,
the
Nationa
Academy
of
Sciences,
and
the
Naunal
Science
and
Technology
Council
(NSTC),
with
support
fron
several
member
agencies
of
the
NSTC.
The
views
summarized
in
this
report
are
those
of
the
Conference
participants
and
donot
represent
the
views
of
the
NSTC
or
the
Institute
of
Medicine
and
Nationa.
Academy
of
Sciences.
This
summary
was
reviewed
for
accuracy
by
the
chairs
of
the
individual
sessioE
of
the,
conference
and
by
the
chairs
of
the
breakout
group
panels.
Funding
for
the
conference
was
provided
by
the
National
Academy
of
Sciences,
the
Office
of
Science
and
Technology
Policy,
the
National
Science
Foundation,
the
National
Aeronaiitics
and
Space
Administration,
the
National
Oceanic
and
Atmospheric
Administration,
the
EnvironmentaI
Protection
Agency,
the
Department
of
Defense,
the
National
Institutes
of
Health's
Fogarty.
Intemtiona1
Center
and
the
National
Institute
of
Environmental
Health
Sciences,
the
Department
of
Agriculture,
the
Centers
for
Disease
Control
and
Prevention;
the
Agency
for
International
Development,
and
the
Department
of
Energy.

Additional
copies
of
this
report
are
available
in
1imited.
quantities
fiom:

Division
of
Health
Sciences
Policy
Institute
of
Medicine
..

21
01
Constitution
Avenue,
N.
W.
XVashington,
DC
2041
8
.
.
.
­.

Copyright
1996
by
the
National
Academy
of
Sciences.
All
rights
reserved.

Printed
in
the
United
States
of
America
3
I
i.

Acknowledgments
3
The
Conference
on
Human
Health
and
GlobalClimateChangethat
is
the
subject
of
this
summary
was
the
product
of
a
collaborative
effort
between
the
Institute
of
Medicine,
the
National
Science
and
TechnologyCouncil(
NSTC),
and
the
NationalResearchCouncil'sBoardon
Atmospheric
Sciences
and
Climate,
Board
on
Sustainable
Development,
and
Polar
Research
Bead.
It
.,
would
not
have
been
possible
without
the
concerted
efforts
and
contributions
of
many
individuals
and
organizations.
The
conference
planners
and,
organizers
are
listed
in
Appendix
By
including
the
NSTC
Working
.Group,
the
sponsoring
agencies,
the
IOM/
NAS
Steering
Committee,
and
the
responsible
staff.
The
.conferencespeakers,
background
paper'
authors,.
andsessionchairsdeservespeciiil
recognition
and
thanks
for
'their
efforts
,and
arelisted
in
Appendix.
C.
The
approximately
300
conference
participants
were
zin
important
part
of
this
activity,
especially
in
stimulating
discussion,
providing
ideas,
'and
developing
the
strategies
that
were
the
products
of
the
individual
working
group
panels.
These
individuals
are
included
in
the
list
of
conference
registrants
in
Appendix
C.
Of
particulafnote,
Eric
Chi&
n,
Bob
Shope,
and
,Mary
Wilson
are
acknowledged
for
their
contribution
in
both
raising
and
discussing
these
issues
with
Vice
President
Albert'
Gore,
Jr.,
in
the
formative
stages
of
the
conference's
development
and
for
their
participation
in
the
conference
itself.
We.
also
would
like
to
acknowledge
Vice
President
Gore
for
his
initiative
in
requesting
.that
this
conference
take
place,
and
for
his
contribution
as
a
participant
and
'qeaker.
..

.I
...
111
.I
Contents
I
3
EXECWIVE
SUMMARY
..................................................................................................................
1
BACKGROUND
AND
OVERVIEW
.......
,...
i
..........
..
..........................................................................
2
Greenhouse
Warming,
5
Ozone
Depletion,
6
­

POTENTIAL
HUMAN
HEALTH
EFFECTS
OF
GLOBAL
CLIMATE
CHANGE
.....
..:
....
:
........
I...
7
Infectious
Disease,
8
­.

Vector­
Borne
Infectious
Diseases,
8
Non­
Vector­
Borne
Infectious
Diseases,
9
Heat
Stress,
9
Skin
Cancer,
Cawacts,
and
Immune
Suppression,
12
Food
Production
and
Nutritiond'
Health,
13
FreshWater
Quality
andQuantity,
13
..

Air
Pollution
and
Allergens,
13
Weather
Diskters
and
Rising
Sea
Level,
14
Social
and
Demographic
Dislocations,
14
Direct
Effects
on
Human
Health,
9
.

Indirect
Effects
on
Human
Health,
13
POLICY
IMPLICATIONS
..................
........................
......................................................................
15
,
Panel
Reports,
15
Global
Surveillance
and
Response,
16
Disease
Prevention,
17
Education
for
the
Medical
and
Public.
Health
Communities;
19
InternationalCooperation,
22
.
­.

.I
­.

v
..
""*
U
,/p
I
~
.
Research
and
DevelopmentNeeds,
L­
Public
Outreach
and
Risk
Communication,
24
s
w
y
OF
PRIORITIES
AND
STRATEGIES
..................................................................

&FERENCES
AND
FURTER
READING
..............................................................
................

APPENDIXES
A
National
Science
and
Technology
Council
(NSTC)
Sponsoring
Members,
Interagency
Working
Group,
Institute
of
Medicine
(IOM)
Steering
Committee,
and
Staff,
3
1
B
Conference
Agenda,
35
C
Speakers,
Authors,
Chairs,
and
ConferenceRegistrants,
41
D
AbstractsofConferencePresentations,
57
4
c
*
..

Conference
on
Human,
Health
and
'
.
Global
Climate
Change
Summary
of
the
Proceedings
J
J
..

.
..
..

­.
,­
/

4
Conference
on
Human
Health
and
Global
Climate
Change:
Summary
of
the
Proceedings
I
i
EXECUTIVE
SUMMARY
Observed
changes
in
the
Earth's
climdte
over
the
past
100
years
appear
to
be
consistent
with
'

theoreticalmodels
ofgreenhousewarming,
accordingtotheparticipants
in
arecentscientific
conference
on
Human
Health
and
Global
Climate
Change,
cosponsored
by
the
National
Science
and
TechnologyCouncil
OIJSTC)
andtheInstituteofMedicine
(IOM).
'
Thesemodelssuggestthat,
without
major
changes
in
environmental
policy,
we
could
expect
to
see
even
greater
changes
in
global
climate
over
the
next
100
years.
These
changes
could
produce
'alterations
both
&physical
systems
(e.
g.,
higher
temperatures,
heavierrainfall,
and
risingsealevel)
and
in
ecosystems(
e.
g.,
forests,
agriculture,
marine
ecologies,
and
the
habitats
of
various
insects
and
animals).
In
addition
to
the
global
changes
associated
with
greenhouse
warming,
a
continuing
depletion
of
stratospheric
ozone
would
increase
the
amount
of
ultraviolet
radiation
that
reaches
the
Earth's
surface,
causing
increased
rates
of
skin
cancer,
cataracts,
and
i
m
u
n
e
suppression.
The
focus
of
concern
to
.the
conference
participants
was
the
substantial
risks
to
human
health,
including
both
direct
risks
(e.
g.,
death
in
heat
waves
or
floods,
skin
ckcer)
and
indirect
risks
(e.
g.,
changes
in
foodproductionorthedistributionandincidenceofvector­
bornediseases)
that
are
believed
to
be
associated
with
changes
in
global
climate.
The
indirect
risks
appear
to
be
the
most
difficult
to
cope
with,
particularly
those
posed
by
emerging
and
reemerging
infectious'diseases
such
as
cholera,
malaria,
dengue
fever,
and
Hantavirus.
These
risks
are
of
particular
concern
in
regions
and
populations
that
are
already
'vulnerable
due
to
crowding,
malnutrition,
poor
sanitation,
and
political
or
economic
instability.
,
.
'

The
general
agreement
that
emerged
during
the
conference
was
that
changes
in
the
global
climate
could
pose
significant
risks
to
human
health.
Much
remains
to
be
done
to
clarify
the
exact
linkages
between
human
activities,
global
climate
change,
and
human
health,
but
the
lack
of
complete
.
.

data
should
not
be
used
as
an
excuse
for
inaction.
Instead,
the
precautionary
principle
should
apply:
If
the
risk
to
public
health
is
great,
even
if
there
is
uncertainty,
both
policy
and
action
should
be
biased
infavor
of
precaution.
,.

In
discussing
the
poIicy
implications
of
global
climate
change
for
h
m
health
in
the
United
Skates
and
thc
international
community,
participants
identified
a
number
of
actions
that
should
be
taken,
including(
a)
thecreation
of
a
globalsurveillanceandresponsenstwork;
(b)
increased
'The
conference
was
held
at
the
National
Academy
of
Sciences
on
September
11­
12,
1995,
and
was
attended
by
more
than
300
people
(see­
Appendix
C).
.1
cu~
vPEREiVCE
ON
Xfhl2
4J
HEALTH
AND
GLOBAL
CLIUq
TE
Ci
coordinab
among
nations
and
scientificdiscipl
3;
(c)
multidisciplinaryresearch
on.
th.
between
~

,bal
climate
change
and
human
health;
(d)
improved
environmental
health
kifi
health
professionals;
and
(e)
an
outreach
program
to
inform
and
educate
the
public
about
the
of
global
climate
change
on
human
health.
In
the
face
of
current
fiscal
constraints,
these
effofi
be,
based
on
identifylng
and
linking
together
existing
activities,
facilities,
organizations,
and
fi
Zgencies.
i
/­
i
BACKGROUND
AND
OVERVIEW
In
October
1994,
following
a
meetingwithconcernedscientists
and
medical
experts
Chivian,
BobShope,
and
Mary
Wilson),
VicePresidentGoreasked
therOffice
of
Science
TechnologyPolicy
(OSTP)
and
theCouncil
on
Environmental
Quality
(CEQ)
to
orgmi;
conference
on
the
potential
human
health
risks
posed
by
global
climate
change,
and
strategic
address
them­
such
as
global
health
surveillance,
public
outreach,
and
education.
Members
of
NSTC,
OSTP
and
CEQ
formed
a
working
group
to
develop
a
preliminary
agenda
for
the
confert
andlaterrequestedthatthe
l
d
M
join
inplanning,
organizing,
andconductingthe
confers
(Appendix
A
presents
a
list
of
the
sponsoring
agencies,
the
IOM
steering
committee,
and
confere
orgikizing
staff.)
The
purpose
of
the
conference
was
twofold:
I
1.
To,
bring
togetheradiverse,
interdisciplinarygroup
of
expertstoaddressthe
poten1
effects
of
global
climate
change
and
ozone
depletion
on
the
current
and
fkture
incidence
of
&sea
heat
stress,
food
and
water
supplies,
and
air
pollution;
and
2.
To
discuss
initial
strategiesforimprovingresearch
and
deveIopment
(R&
D),
glot:
health
surveillance
systems,
htalth
care
and
disease
prevention,
medical
and
public
health
communi
education,
international
cooperation,
and
public
outreach.
­

It
is
important
to
note
that
the
focus
of
the
`conference
was
human
health.
Presenting
evidenc
of
whether
or
not
global
climate
change
is,
has,
or
will
OCCW,
was
not
the
primary
focus.
Participant
­were
asked
rather
to
work
within
an
"if/
then?
type
of
scientific
.exercise:
If
global
.climate
chang
occurs,
what
are
the
potential
adverse
human
health
effects
and
what
strategies
should
be
developec
to
address
them?
The
first
day
of
the
two­
day
conference­
was
filled
with
scientific
presentations
and
a
plenary
discussion
on
the
current
state
of
knowledge
about
global
climate
change
and
its
potential
risks
for
human
health
(see
the
agenda,
Appendix
B),
including
a
presentation
by
Vice
President
Gore
(see
Box
1).
On
thesecond
day,
participants`
discussedhealthpolicyimplicationsandpotential
intervention
strategies
in
a
series
of
panels.
Each
panel's,
findings
were
presented
and
discussed
by
the
conference
participantslin
a
final
plenary
`session.
Approximately
300
scientists,
health
care
providers,
policymakers,
academicians,
federal
and
state
officials,
industry
representatives,
and
others
attended
the
conference
and
participated
in
developing
the
strategies
(see
Aypenoix
C).
BOX
I.
The
Interplay
of
Climate
Change,
Ozone
Depletion,
and
Human
Health'
3
­
Albert
Gore,
Jr:
'Vice
President
of
the
United
States
I've
spoken
before
about
the
radical
changes
that
have
occurred
in
our
environment
just
in
my
lifetime.
As
i
s
often
the
case,
when
a
fundamental
change
takes
place,
one
can't
point
to
a
single
causal
factor
to
explain
it.
In
this
case,
I've
come
to
believe,
that
this
radical
change
in
the
relationship
between
civilization
and
the
Earth
has
come
about
because
of
the
confluence
of
three
factors
at
the
same
time,
the
first
being
the
population
explosion,
which
is
now
adding
the
equivalent
of
one
China's
worth
of
people
every
10
years.
Thesecond
change
is
the
scientific
and
technological
revolution,
which
has
dramatically
magnified
the
average
impact
that
each
of
the
billions
of
people
on
Earth
can
potentially
have
on
the
Earth's
environment.
And
the
third
factor,
the
most
subtle
in
some
ways
but
the
most
important
in
other
ways,
.'.
.
there
has
been
a
change
in
thinking
about
our
duty
to
consider
the
future
consequences
of
our
present
actions
and
a
sometimes
willful
asdrtion
that
we
can't
possibly
have
any
meaningful
impact
on
the
Earth's
environment,
therefore
we
shouldn't
think
about
it
much
less
wow
about
it
or
study
it
in
detail.
Together,
these
three
elements
have
combined
to
produce
what
some
of
youwouldcall
a
discontinuity:
a
fundamental.
change
in
the
relationshipbetweenhuman
civilization
and
the
earth.
There
is
a
scientific
consensus
on
the
most
salient
issues,
a
revisionist
few
not
withstanding:
We*
know
that
human
activities
are
causing
the
atmospheric
concentrations
of­
greenhouse
gases
to
increase
dramatically
in
the
atmosphere.
Carbon
dioxide
has
increased
nearly
30
percent
since
the
industrial
revolution,
methane
has
more
than
doubled,
and
nitrous
oxide
has
gone
up
by
15
percent.
We
also
know
that
the
current
trends
are
leading
to
an^
even
:

more
rapidaccumulation
of
greenhou'se
gases
and
that,
as
this
trend
continues,
the
concentration
of
greenhouse
gases
will
dontinue
to
mount.
Now,
in
addition
to
the
greenhouse
gases,
human
activities
have
increased
the
atmospheric
concentrations
of
sulfate
aerosols­
the
keyingredient
in
acid
rain­
especially
over
industrialized
areas
in
the
Northern
Hemisphere,
'

warmest
years
this
century
have
all
occurred
since
1980.
There
are
plentyof
other
measures­
from
the
tree­
ring
.record
to
the
record
in
land­
based
.
glaciers­
thatall
demonstrate
that
the
current
period
is
by
far
the
hottest
that
we
have
been
able
to
measure.
And
the
evidence
is
getting
ever
stronger
that
this
warming
nowunderway
is
not
due
to
natural
variability,
but
to
human
activities.
..

The
real
question
is:
"What
will
happen
i
n
the
future?"
­Without
climate
change
policies
that
limit
global
emissions
of
greenhouse
gases,
there
is
no
doubt
that
the
Earth's
climate
will
change.
It's
not
a
question
ofwill
it
change,
it
is
a
question
of
when,
by
how
much,
and
where.
The
question
of
when
is
now
being
answered.
It
has
already
begun
to
change
significantly.
And
the
best
evidence
is
consistent
with
a
prediction
that,
in
the
lifetimes
of
people
now
living,
we
will
commit
the
world
to
an
increase
of
up
to
3
O
and
4°
C­
up
to
8OF.
The
scientists
warn
us
that
change
is
coming.
In
just
the
last
century,
the
Earth's
temperature
has
risen
by
about
0.5OC,
or
I°
F.
The
nine
'
..

Continued
'

*Excerpts
from
remarks
at
the
Conference
on
Human
Health
and
Giobal
Climate
Cnange,
September
11,
1995.

­.
'i
c
.Hc
till
globalwarmingaffect
US?
There
a
;lea@+
profoundimplications
at
the
regie
level
f
ood
security,
water
supplies,
natural
eCOSystemS,
loss
of
land
due
to
sea
level
r
andhumanhealth.
A
temperature
increase
of
2"
to
8°
F
is
projected
to
double
heat­
rela
deaths
in
NewYork
City
andtriplethenumberof
deaths
in
Chicago,
LOS
Angeles,
2
Montreal,
Andan
increase
of
8OF
maybeGoKeiated
with
an
increase
in
theheauhumic
So
will
those
withchroniccardiovascularandrespiratory
diseases.
The
past
Summe
stunning
number
of
deaths
in
Chicago­
over
500
in
just
a
few
days­
make
these
hypothes
all
f30
real.
Changing
temperatures
and
rainfall
patterns
are
predicted
to
also
increase
the
spread
infectious
diseases.
Insects
that
carry
disease
organisms
may
now
move
to
areas
that
we.
once
toocold
for
themtosurvive.
These
newbreeding
sites
and
higher
temperatures
mz
also
speed
reproduction.
Diseases
we
hadhopedwere
just
a
memory
in
this
county
ar
suddenly
a
renewedthreat.
Cholera
is
resurgent
in
our
hemisphere.
After
years
ofbein
contained
in
much
of
the
world,
Dengue
Fever
has
returned
to
countries
that
had
not
seen
th
disease
in
50
years.
Malaria,
too,
is
a
global
concern,
and
some
of
the
new
strains
are
mort
troubling
thananythathavebeen
seen.
Malariaalready
infectsseveralhundred
millior
people
each
year­
mainlydn
the
Tropics.
But
this
July,
for
the
first
time
in
40
years,
more
thar
100
people
contracted
maIat4
in
a
Russian
city.
And
besides
the
return
of
old
diseases,
there
are
new
ones
on
the
U.
S.
scene,
such
as
the
hantavirus
in
the
Southwest.
Unfortunately,
ignoring
the
news
does
not
make
it
better.
Closing
your
eyes
to
a
problem
doesn't
make
it
vanish.
You
can't
simply
wish
ozone
holes
away.
SO
it
astounds
me,
in
light
of
all
the
data
that
has
been
collected
over
the
years,
that
some
are
once
again
challenging'the
fact
that
there
is
ozone
depletion.
And
what's
even
more
amazing
is
that
some
people
are
listening.
Ladies
and
gentlemen,
we
have
an
extraordinary
international
consensus:
We
have
thousands
and
thousands
of
atmospheric
measurements
linking
manmade
CFCs
toglobal
ozone
depletion.
We
all
know
that
depletion
of
the
ozone
layer
increases
the
amount
of
UV­
B
radiation
that
reaches
the
Earth.
And
so
nowwehave
to
confront
the
fact
that
the
observed
depletion
of
ozoneof
5­
10
percent
in
summertime,
whenpeople
are
outdoors
a
lot,
will'
increase
nonmelanoma
skin
cancer
in
fair­
skinned
populations
by
about
10­
20
percent.

and
cataracts
are
already
the
third­
largest
cause
of
preventable
blindness
in
the
United
States.
These
numbers
would
be
much
higher
yet
were
it
Rot
for
the
success
of
the
Montreal
Protocol..
We
must
not
forget
though,
that
evenwith
that
world­
wide
action,
it
will
be
until
the
middle
of
the
next
century
before
the
ozone
layer
recovers.
Well,
for
the
past
25
years,
the
United
.States
has
been
committed
to
the
bipartisan
effori
to
protect
the
environment.
.
.
.
President
Clinton
has
.
.
.
fought
to
make
sure
that
the
United
States
is
at
the
forefront
of
a
globalenvironmentalmovement.
We'restriving
to
return
greenhouse
gas
emissions
to
1990
levels
by
the
year
2000.
We're
striving
to
convince
others
to
make
as
much
progress
as
is
possible.
We're
engaged
in
internationathegotiations
to
address
this
globalproblem.
We'rehelpingtodevelop
treaties
notonly
for
the
protection
of
our
awn
nation,
but
for
the
health
and
welfare
of
the
world
community
of
which
we
are
a
part.
'
We
know
that
science
is
essential
to
our
understanding
of
global
problems.
Ladies
and
gentfernen,
the
role
of
the
scientific
community
in
articulating
cleariy
the
best
accepted
understanding
of
what
we
know
and
what,
we
can
say
with
sufficient
confidence
to
enable
the
American
people
to
takeprudent
measures
10
safsguard
our
future
is
abso!
y?
e!
y
critical.
"­.
.I
,
index
of
1
2
O
to
15OF.
The
very
young,
the
elderfy,
anb
the
poor
will
be
the
ones
most
at
­
In
addition,
there
w
i
l
l
be
an
increase
in
the
incidence
of
cataracts
and
other
eye
lesions,
5
..'
Greenhouse
Warming
T.

4
Without
the
naturallyoccuning"
greenhouseeffect,"
Earth
would
be
toocoldtosustain
life
as
we
know
it.
The
greenhouse
effect
results
from
water
vapor,
carbon
dioxide,
and
other
trace
gases
in
the
atmosphere
that
trap
solar
heat
as
it
is
reradiated
from
the
Earth's
surface.
The
net
effect
is
to
keep
the,
ph.
net
about
33°
C
(60°
F)
wannerthan
it
wouldbeotherwise.
Inthepast
century,
however,
human
activities
have
added
substantially
to
this
effect
by
releasing
additional
greenhouse
gases
into
the
akosphere,
primarily
through
combustion
of
fossil
fuels.
Carbon
dioxide
concenkations
have
increased
nearly
30
percent,
nitrous
oxide
about
15
percent,
and
methane
approximately
100
percent.
The
principalsource
of
the
emissions
thatproducetheatmosphericconcentrationshasbeen
the
burning
of
fossil
fuels
(coal,
oil,
and
gas),
although
agriculture
and
deforestation
contribute
a
share.
There
is
a
growing
consensus
in
the
scientific
community
that
the
increase
in
greenhouse
gases
has
contributed
to
a
warming
of
the
earth's
surface
by
between
0.3"
and
0.6"
C
(0.5"
and
1.
l0F),
on
average,
over
the
past
100
years
(see
Figure
1).
In
some
regions,
particularly
in
the
industrialized
areas
of
the
Northern
Hemisphere,
this
warminghas
been
masked
by
increased
concentrations
of
air
.
pollutants
such
as
sulfate
aerosols,
which
reflect
solar
radiation
(and
thus
serve
to
counter­
balance,
in
part,
the
warming
that
might
be
seen
otherwise).
Nevertheless,
the
nine
warmest
years
in
this
century
have
occurred
since
1980,
andthereisconsiderableevidencetosupportthis
­warming
trend
(see
"References
and
Further
Reading,"
p.
28):
decreases
in
Northern
Hhsphere
snow
cover
and
Arctic
sea
ice,
the
retreat
of
glaciers
in
all
of
the
world's
mountain
ranges,
and
a
measurable
rise
in
average
sea.
level­
10
to
25
centimeters
(4
to
10
inches)
over
'the
past
100
years­
mainly
due
to
the&
expansion
of
water.
m
i
l
e
emissions
of
greenhouse
gases
'
4
1
certainly
continue
in
the
future,
the
exact
amounts
will
depend.
on
population
growth,
economic
development,
energy
technologies,
and
policy
variables.
Nevertheless,
according
to
the
participants,
it
seems
reasonable
to
expect
that
global
emissions
of
carbon
dioxide
will
rise
in
the
.short
term
from
the
current
level­
of
approximately,
6
billion
tons
of
carbon
per
year,
to
between
8
billion
and
15
billion
tons
per
yeaf
in
2025,
'and
could
range
from
5
billion
to
36
billion
tons
per
year
by
2100.
This
'would
mean
that
atmospheric
concentrations
of
carbon
dioxide­
which
were
200
parts
per
million
(ppm)
during
the
last
ice
age
and
about
280
ppm
in
preindustrial
times­
could
rise
from
today's
350
ppm
to'anywhere
from
500
to
900
ppm
by
2100.
The
scientific
community
has
growing
confidence
in
the
ability.
of
computerized
general
circulation
models
to
predict
the
climate
impacts
of
such
changes
in
greenhouse
gases.
These
models,
whichprovide
an
increasinglygood
fit
betweentheoryandobservationofpastglobalclimate
changes,
indicatethat,
in
a
worldwithapproximatelytwicethecurrentconcentrationofcarbon
'

dioxide,
the
global
mean
temperature
will
increase
by
1"
to
4°
C
(2"
to
7"
F),
with
significant
regional
variations
(e.
g.,
somewhat
less
warming
in
the
Northern
Hemisphere
due
to
air
pollution).
Average
.evaporation
will
also
increase,
and
hence
average
precipitation,
again
with
regional
variations
(more
rain
in
some
places,
especially
in
winter,
less
rain
in
others,
especially
in
summer).
Sea
level
will
rise
by
another
15
to
90
centimeters
(6
to
35
inches)
over
the
next
100
years.
6
.
­.,
CONFERENCE
ONHU­
MX~
EALTHAND
GLOBAL
CLIMATE
c
m
partA
­$
ants
noted
that
the
impact
of
such
changes
on
natural
and
human
systems
mixed.
Increased
.carbon
dioxide
concentrations
would
have
a
"fertilizer"
effect
for
some
plants,
not
for
others,
leading
to
changes
in
natural
plant
communities
and
ripple
effects
on
animal
spec
Overall,
the
balance
would
probably
be
tilted
in
favor
of
"weedy''
species­
those
with
higher
rate
reFoduction
and
dispersal­
to
the
detriment
of
biological
diversity.
Tropical
forest
communities
be
affected,
.and
there
will
probably
be
some
die­
off
in
boreal
foress
as
well.
Temperature­
re12
changes
in
the
oceans
will
affecttheworld'scoralreefs
and
oceanfisheries.
Global
agricdh
production
may
be
unchanged,
although
increased
production
in
northern
latitudes
might
be
offset
decreases
in
tropical
regions
where
many
populations
are
already
malnourished.
Coastal
populatic
may
be
dislocated
by
changesinsealevel,
andthere
.will
likelybeincreasednumbers
of
06
"ecological
refbgees"
as
well.

ir
Ozone
Depletion
A
thin
layer
of
ozone
h
i
g
h
the
atmosphere
(the
stratosphere)
protects
life
on
earth.
shie
:I
dir
the
Surface
by
absorbing
much
of
the
ultraviolet
radiation
from­
the
&.
However,
surface'
ozone
(
the
1ower.
atmosphere
or
troposhpere)
is
a
major
component
of
urban
smog
and
ca.
also
serve
as
I
Temperature
change
PC)

4
I
'

20,000
10,000
­5000
1,000
200
.
100
18,
OOO
vcan
­
A
1.800
w
a
r
s
­
`
300vean
>

Number
of
years
befori
p
r
m
n
t
(note:
quasi­
iog
scale)

FIGURE
I
.
Variations
in
average
global
temperature'
over
the
past
20,000
years
and
predictions
for
the
next
century.
(McMichael,
1993)
­.
.
SUMIUARY
OF
THE
PROCi'
XVGS
7
greenhouse
gas;
the
protective
ozone
layer
resides
some
10
to
40
kilometers,
or
6
to
25
miles,
above
,.
the
.Earth's
surface.
Solar
energy
recombines
diatomic
oxygen
(03
into
triatomic
ozone
(OJ;.
these
`
molecules
are
broken
down
to
0,
by
naturally
occurring
compounds
containing
nitrogen,
hydrogen,
and
chlorine;
and
ihe
cycle
begins
again.
In
the
past
50
years
human
activities
have
added
millions
of
tons
of
ozone­
depletingchemicalstotheatmosphere,
primarilythrough
the
widespread
use
of
chlorofluorocarbons
(CFCs)
in
refrigerators,
spray
cans,
foam
insulation,
and
cleaning
compounds.
In
theory,
these
ozone­
depleting
chemicals
rise
up
in
the
atmosphere
and
destroy
the
ozone
layer
faster
than
it
is'
naturally
restored.
Indeed,
in
1985,
researchers
reported
dramatic
declines
in
ozone
concentrations
over
Antarctica
during
the
southern
spring.
This
seasonal
"hole"
in
the
ozone
shield
has
grown
larger
and
appeared
earlier
in
subsequent
years.
Many
other
factors
might
contribute
"

to
these
findings,
including
sunspot
cycles
and
the
isolation
and
extreme
cold
of
the
Antarctic
weather
system,
but
CFCs
and
other
ozone­
depleting
compounds
were
clearly
implicated.
'
More
recentmeasurementshaveconfirmedthatozonedepletion
is
in
facta
global
phenomenon;
`
although
it
is
lessacute
in
th
troicsand
more
pronouncedtoward
the
poles,
particularly
in
the
Southern
Hemisphere.
At
present
there
is
a
5
to
7
percent
ozone
depletion
over
the
United
States
during
the
summer,
when
people
are
most
likely
to
be
outdoors;
about
11
percent
over
southern
temperate
areas;
and
more
than
50
percent
over
Antarctica.
Every
1
percent
decrease
in
ozone
can
lead
to
a
2
percent
increase
in
nonmelanoma
skin
cancer.
This
phenomenon
is.
expected
to
continue
for
the
next
decades,
despite
international
efforts
to
ban
CFCs
and
to
phase
out
other
ozone­
destroying
compounds.
Peak
ozone
depletion
will
occur
around
the
turn
of
the
century;
recoveqis
expected
to
occur
over
the
following
50­
year
period.
i.

J
P
POTENTlwL
HUMAN
HEALTH
EFFECTS
OF
GLOBAL
CLIMA'IE
CHANGE
Conference
participants
noted
that
the
anticipated
human
health
risks
caused
by
global
climate
change
will
not
be
localized;
instead,
they
willoccur
on
alargescale,
impinging
on
entire
populations.
In
additiontoincreasingthefamiliar,
direct6ffectsofclimate(
i.
e.,
extreme
weather
events
such
as
heatwavesandfloods),
globalchangewillalsoinvolveavarietyof
indirect
risks
arising
from
the
disturbance
ofnaturalsystems(
e.
g.,
the.
ecologyofinfectiousdiseases,
food
production,
andfresh
`water
supplies).
Forecastingtheserisks
is
acomplex,
uncertaintask,
and
encompasses
a
long
time
horizon.
(
Box
2
summarizes
a
pair
ofpresentations
on
El
Nifio
as
an
analogue
for
long­
term
global
climate
change.)
The
health
effects
ofglobalclimate.
changespanacontinuumfromdirectto
indirect,
as
shown
in
Figure
3.
In
the
long
run,
the
indirect
effects
of
disturbing
natural
systems
may
have
greater
cumulative
impacts
on
human
health,
and
most
of
those
impacts
will
be
adverse.
As
summarized
in
the
most
recent
assessment
of
the
United
Nations
Intergovernmental
Panel
on
Climate'Change
(IPCC,
1995)
and
by
various
speakers
during
the
first
day
of
the
conference,
the
most
likely
and
most
serious
health
risks
and
health
effects
of
globalclimatechangeandozonedepletionwould
be
adverse
changes
in
the
following:
I
.
..

'The
1995
Nobel
Prize
for.
Chemistry.
was
awarded
to
Molina
and
Rowland
for
this
research.

..
heat
stress;
skin
cancer,
cataracts,
and
immune
suppression;
vector­
borne
infectious
diseases;
non­
vector­
borne
infectious
diseases;
food
production
and
nutritional
health;
water
quality
and
quantity;
airpollutionandallergens;
weather
disasters
and
rising
sea
level;
and
social
and
demographic
dislocations.

Infectious
Disease
Climate
influences
the
distribution,
fiequency,
types,
and
severity
of
infectious
&seas
humans.
The
interaction
between
climate
and
infectious
diseases
derives
from
the
impact
of
cli
oninfectiousorganisms
(w
h
as
bacteriaandviruses),
on
the
humanhost,
and
onvectors
reservoir
hosts
and
their
ecosydms.
Climate
change
can
increase
the
probability
of
contact
be&
humans
and
infectious
organisms.

Temperatureandrainfallinfluencetheabundance
anddistribution
of
insectvectors
i
animals"
one
source
of
infectious
diseases
in
humans.
Global
climate
change
is
likely
to
affect
geographic
distribution
of
a
n
i
m
a
l
s
and
insects
and
could
expand
transmission
of
infectious
disea
carriedbymosquitoes(
e.
g.
z
malaria,
dengue,
andyellowfever)
andothervectors,
such
as
tic:
sandflies,
and
fleas.
Altered
distributions
of
vectors
are
likely
to
involve
expansion
of
vector­
bor
diseases
into
new
geographic
areas
`md
populations
and
disappezkance
from
other
areas.
For
a
vectc
borne
disease
to
persist
in
a
n
'
i
r
e
a
,
climatic
conditions
must
support
a
complex
interaction
that
rn;
involve
plants,
animals,
insects
and
human
activities.
Extreme
events,
such
as
flooding
and
hurricanes,
that
lead
to
displacement
of
populations
in1
crowded,
temporary
shelters,
or
movement
into
previously
uncleired
lands,
could
also
contribute
t
an
increase
in
vector­
borne
infections.
Vector­
borne
diseases
are
already
a
major
cause
of
illness
and
death
in
tropical
countries
I
where
2.4
billion
people
are
at
risk
from
malaria
and
1.8
billion
from
dengue
fever
(see
Table
1).
The
numbers
of
people
at
risk
from
theseand
other
diseases
will
.increase
with
warmer
temperatures
and
humidity,
particularly
because
these
changes
are
occurring
&nultaneously
with
changes
in
,human
behaviorthatincrease
the
dangers
of
infectious
disease­
mostnotably
international
travel,
population
growth,
rapid
urbanization,
poor
sanitation,
and
changes
in
land­
use
patterns
:that
increase
habitator
bring
humans
in
contactwith
insect.
or
rodent
vectars.
Climate­
related
migrations
could
also
contiibute
to
the
dissemination
of
previocsly
localized
diseases.
Several
vector­
borne
diseases
have
been
increasing
rapidly
in
recmt
yexs,
including
some
that
were
previously
ccnsidsicii
to
be
under
control,
such
as
dengue
fever
and
malaria.
Strong
support
for
public
health
­programs
both
domestically
and
internationally
would
help
to
reduce
this
risk.
.,/
­
,
.

Suh.
fMRY
OF
THE
PROCJLDINGS
Non­
Vector­
Borne
Infectious
Ddeases
i
9
­
*
Changes
in
watertemperatureandtheresultingproliferationofaquaticmicroorganisms
would
tend
to
increase
the
range
and.
severity
of
cholera
and
other.
food­
and
water­
related
diseases
that
can
cause
epidemics
of
diarrhea
and
dysentery.
Cholera
epidemics
are
typically
associated
with
seacoasts
and
rivers,
for
instance,
where
the
cholera
organism,
Vibrio
cholerae,
&ves
by
sheltering
under
the
mucous
coating
of
tiny
invertebrates
called
copepods.
These
hosts,
in
turn,
respond
both
to
water
temperature
and
to
nutrients
(fertilizer,
wastewater)
in
stream
runoff.
Researchers
are
currently
evaluating
the
connection
between
water
temperature,
coastal
currents,
algal
blooms,
and
subsequent
,;
outbreaks
of
cholera
like
those
in
Peru
in
1991
and
Bangladesh
in
1992.
Higher
temperatures
contribute
to
faster
reproduction
by
disease
organisms.
Rates
of
genetic
mutation
also
increase
in
times
ofstress.
Furthermore,
diseasecausingorganismsareremarkably
resilient
and
can
respond
rapidly
to
changes
in
the
physicochemical
awironmknt.
Climatic
and
other
environmental
changes
are
contributing
to
thgselection
and.
emergence
of
genetic
strains
that
are
resistant
to
drugs
and
other
controls.

Direct
Effects
on
Human
Health
Heat
Stress
­

,
An
increase
in
average
temperature
would
probably
be
accompanied
by
an
increase
in
the
number
and
seventy
of
extreme
heatwavesin
some
Teas.
This
would
cause
an
increase
in
illness
and
death,
particularly
among
the
young,
the
elderly,
the
frail,
and
the
ill,
especially
in
large
urban
areas.
Climate
change
would
exacerbate
an
already
large
urban
heat
island
effect
that
exists
in
many
large
cities.
In
fact,
heat­
related
mortality
may
prove
to
,be
the
largest
direct
health
threat
from
global
climate
change.
The
deathsof
726
people
that
were
attributed
to
a
heatwave
in
Chicago
i
n
the
summer
of
1995
may
be
an
extreme
example,
but
it
serves
as
a
possible
indicator
of
what
might
occur
if
climate
change
scenarios
&e
correct.
Mid­
latitudecitiesthatexperienceirregular,
butintense,
heatwavesappearto'
be
most
susceptib1e"
citie.
s
like,
St.
Louis,
Washington,
D.
C.,
and
New
York.
Tropical
and
subtropicai
cities
seem
to
be
less
susceptible,
in
part
because
populations
have
acclimatized
to
the
regularity
of
hot
weather
(although
a
1995
incident
in
New
Dehli
indicates
the
susceptibility
of
tropical
populations
as
well).
People
in
mid­
latitude
cities
mi@
also
acclimatize,
and
air
conditioning
can
mitigate
perhaps
25
percent
of
heat­
relatedmortality(
while
also
requiringincreasedenergyandrefrigerantuse,
thereby
increasing
greenhoLisegasemissions).
In
addition,
summermortalityincreasesmight
be..
partially
offset
by
declines
in
winter
mortality.
However,
much
of
the
research
points
to
a
substantial
increase
in
weather­
related
mortality
der
climate
chapge
conditions.
Despite
these
uncertainties,
there
is
a
clear
need
to
develop
an
adequate
warning
system.
to
alert
the
public
and
governmint
ztgencies
when
oppressive
air
masses
are
expected"
extended
periods
of
extreme
high
tqerature,
light
winds,
high
humidity,
and
intense
solar
radiation.
TABLE
1
lrlajor
Tropical
Vector­
Borne
Diseases
and
the
Likelihood
of
Change
of
Their
Dkmbution
with
Climate
Change
Likelihood
of
Altered
Currently
Population
8:
Infectedor
New
Present
with
C
h
a
r
­
NO.
of
PeopIe
Disease
Vector
Risk
(million)
'Cases
per
Year
Distribution
Change
Malaria
Pllosquito
2,400b
300­
500
million
TropicdSubtropics
+t)­

Schistosomiasis
Water
Snail
600
200
million
TropicdSubtropics
U
Lymphatic
Filariasis
Mosquito
1,094'
117
million
TropicdSubtropics
+

African
Tsetse
Fly
5
9
250,000­
300,000
Tropical
Africa
f
Trypanosomiasis
casedyr
(Sleeping
Sickness)

Dracunculiasis
Cmsaceau
100'
1oo,
ooo/
yr
South
AsidArabian
(Guinea
Worm)
(~
PePQd)
?
3
PeninsuldCentral­
West
Africa
Leishmaniasis
Phlehtomine
350
Sand
Fly
Onchocerciasis
Black
R
y
123
(River
Blindness)

American
Triatomine
100'
Trypanosomiasis
Bug.
(Chagas'disease)

Dengue
,Mosquito
1,800
12
million
infected,
500,000
new
.cases/$

17.5
million
18
million
10­
3Omilliodyr
­
AsidSouthern
+

Americas
EuTopefAfricd
­

Africa/
Latin
America
++

Central
and
South
+
America
All
Tropical
Countries
tt
Yellow
Fever.
Mosquito
450
4,000
casedy­
r
Tropical,
South
+i­

.
.
hericaand
Africa
NOTE:
+
=
likely,
"I­
=
very
likely,
­++
t
=
highly
likely,
and
?
=
unknown.

'Top
three
entries
are
population­
prorated
projections,
based
on
1989
estimates.
'WHO,
1995.
.e
Michael
and
Bundy,
i995.
'WHO,
1994a
Ranque,
personal
ccmmunication.
'Annual
incidence
of
viscerai
leishmaniasis;
annual
incidence
of
cutaneous
leishmaniasis
is
1
million­
1.5
million
casedyr
(PAHO,
1994).
'WHO,
1995
...
,z
SOURCE:
PCC,
1995.
~,

I
1
"
,
I
SUMhMY
OF
THE
PROCEL
NGS
BOX
2.
El
Niiio:
Analogue
for
Long­
Term
Global
Climate
Change?
'

J.
Michael
Hall
Director,
Office
of
Global
Programs,
National
Oceanic
and
Atmospheric,
Administration
and
Paul
Epstein
Harvard
Medical
School
­

The
El
Nitio
southern
oscillation
(ENSO)
may
represent
an
analogue
not
only
for
larger­
scale
globalclimate
change
and
its
consequences,
but
also
for
the
steps
that
might
be
taken
to
monitor
and
respond
to
globalclimate
changes
that
threaten
human
health.
Prevailing
winds
in
the
tropics
create
a
pool
of
warm
water
in
the
western
Pacific
Ocean,
a
regionthatdrivesmuch
of
the
atmospheric
heating
that
controls
the
world's
weather.
Periodically,
.however,
the
trade
winds
'relax
or
even
reversethemselves,
releasing
this
pool
of
warm
water
and
setting
in
motion
changes
in
water
temperature,
sea
level,
and
coastal
currents
off
South
Americathat­
becausetheyhappenaround
Christmas­
are
known
by
the
name
of
"El
Nitio."
This
oscillation
in
atmosphericand
ocean
conditions,
whichnormally
happens
every
3
to
.7
years,
causes
notonly
the
collapse
of
ocean
fisheries
in
the
eastern
Pacific,
but
also
characteristic
changes
in
the
weather
in
otherregions,
including
drought
in
northeastern
Braziland
increased
precipitation
in
the
southeastern
United
Sjates
(see
Figure
2).
The
international
scientific
community
has
linked
a
huge
network
of
ocean
buoys
and
remote­
sensingsatellitestoobserve
and.
study
the
dynamics
of
the.
ENSO
phenomenon.
Interdisciplinary
research
andanalysishave
led
to
thecreationof
multisector
models
that
can
predict
the
occurrence
and
effects
of
these
changes.
The
ENSO
forecasts
made
by
these
models
are
alreadyreliableenough
to
support
major
policy
decisions.
In
both
Peruand
Brazil,
.for
example,
governments
are
making
decisions
about
which
cropsto
plant,
and
how
many
acres
to'cultivate,
based
on
12­
month
forecasts
of
ENSO­
related
rainfall.
.More
research
and
refinement
will
be
needed
before
these
predictive
models
will
be
useful
in'
regions
outside
the
tropics
and
in
sectors
other
than
agriculture,
including
public
health.
Nevertheless,
this
predictive
approach
.to
.short­
term
ENSO
changes
may
have
major
relevance
to
the
study
of
long­
term'changes
i
n
the.
globa1
climate.
'
.
ENSO­
related
algal
blooms
off
Peru;
for
instance,
are
part
of
what
appears
to
be
a
global
epidemic
of
algal
blooms
caused
in
part
by
warmer
oceans
everywhere.
These
blooms
represent
"environmental
reservoirs"
for
microbes,
such
as
Vibrio
cholerae,
the
cause
of
cholera
in
humans.
Similarly,
insect
and
rodent
populations
also
have
increased
following
the
mild,
wet
winters
associated
with
El
Nitio,
and
this
can
have
serious
impacts
in
areas
wh,
ere
these
animals
act
as
pests
in
agriculture
or
as
vectors
for
diseases
such
as
malana
and
Lyme
disease.
Consequently,
the
ability
to
understand
and
anticipate
the
relations
between
globalclimats
changes,
environments!
responspc,
2nd
threlts
to
human
health
may
have
significant
value
in
developing
early
warning
systems
to
protect
vulnerablepopulations.
Multidisciplinary,
multisectoralresearchto
.
developreliable
indicators
could
have
extremely
broad
benefits
for
public
health.
..

"Excerpts
from
a
special
briefing
at
the
Conference
on
Human
Health
and
Global
Climate
Change,
11,
,1995.
.
.
i
11
­,/
'
i
,­

12
­
60"
N
40"
N
20"
N
EQ
20"
s
40"
s
Northern
Hemisphere
Winter
J
120"
E
160"
W
a
o
0.
w
:­­*=
dry
_.
=
dry
&
warm
m=
wet
mm
=
wet
&
warm
ma
=
warm
ma=
wet
&
cool
­"

FIGURE
2.
Pictoral
representation
of
global
climate
impact
anamolies
due
to
ENSO.
(Provided
by
NOM,
based
on
work
of
C.
Rppelewski
and
collaborators)

Skin
Cancer,
Cataracts,
and
Immune'
Suppression
..

Ozone
'depletion
can
have'
both
direct
p
d
indirect
effects
on
ecological
systems
and
hum2
health.
Increased
exposure
to
.ultraviolet
radiation
(especially
UV­
B)
can
have
harmful
effects
e
photosynthesis
(on
land
and
sea),
with
potejntidy
disruptive
impacts
on
food
production
and
th
stability
of
ecosystems.
The
most
important
direct
human
.health
effect
would
be
an
increase
i
nonmelanoma
skin
cancers,
espe&
ally
in
fair­
skinned
populations.
Such
cancers
are
already
a
majc
problem
in
the
United
States,
'
w
i
t
h
about
1
million
new
cases
per
year.
Furthermore,
cwent
model.
suggest
a
two
percent
increase
in
incidence
for
every
one
percent
decrease
in
stratospheric
ozone.
The
current
scenario
for
phaseout
of
CFCs
predicts
a
25
percent
increase
in
skin
cancer
by
2050
at
50"
N
latitude,
relative
to
the
198Oincidence.
Melanoma
is
a
less
fiequent
but
far
more
deadly
skin
cancer,
whose
relationship
to
W­
B
exposure
remains
uncertain.
Both
types
of
skin
cancer
have
'
a
long
lag
time
betweenexposure
and
disease;
the
effects
of
increased
W­
B
&y
not
be
seen
until
after
2050,
Idcreased
W­
B
can
also
be
expected
to
increase
the
frequency
of
cataracts,
which
can
lead
to
blindness
in
all
populations.
Current
estimates
indicate
a
0.3
to
0.6
percent
increase
in
new
cataractcasesforevery
1
percent
decreaseinstratosphericozone.
Ozone
depIetion
may
also
contribute
to
the
frequency,
severity,
and
duration
of
someinfectious
diseacs
&e
io
dhaviolet's
ability
to
suppress
the
ilmune
system.
There
are
m
y
~c
z
t
t
i
i
t
k
s
about
the
effect
of
W
­B
on
i
m
u
n
e
responses,
althoughitappearsthatneitherpigmentationnor
m
s
c
r
m
s
offer
gffective
protection.
_­
.
­I
/

,
/

sI/&€
A4ARY
OF
THE
PROCLdIiVGS
­,

Indirect
Effects
on
Human
Health
'
Food
Production
ind
Nutritional
Health
13
Global
climate
change
would
have
mixed
effects
on
the
productivity
of
agriculture,
livestock,
and
fisheries.
In
tropical
and
subtropical
areas,
global
climate
change
may
lead
to
droughts,
flooding,
and
the
emergence
of
new
plant
diseases,
decreasing
food
production
in
many
areas
where
food
supplies
are
already
insecure.
Meanwhile,
crop
productivity
may
increase
in
other
regions,
mostly
in
the
higher
temperatelatitudessuch
as
Canada,
Siberia,
andPatagonia.
However,
agricultural
f.
projectionsarestronglydependentonassumptionsabouttechnologicaladvancesandpatterns
of
consumption.
Over
800
million
people
are
chronically
undernourished
today,
particularly
in
the
developing
world,
andmalnutritionisanunderlyingcause
of
childhoodmortality.
Withfurtherpopulation
growth,
malnutrition
may
increase
the
vulneraJhty
of
these
populations
to
endemic
diseases
and
epidemics.
Some
areas
may
need
to
change
crops,
planting
practices,
and
diet,
further
increasing
vulnerability
during
the
period
of
transition.
Such
regions
might
be
helped
by.
advance
warning
of
.conditions
that
might
cause
crop
failures.
Overall,
:
modelsprojecttheworldmay
be
abletoproduceenoughfoodtofeedfuture
populations..
However,
.changes
in
regional
patterns
of
production
could
be
significant,
and
in
&e
long
term,
nutritional
security
can
only
be
ensured
through
education
and
training,
higher
incomes,
­
favorable
market
mechanisms,
political
stability,
and
population
controls.

Fresh
Water
QuaZiv.
and.
Quantiv
Great
spatial'
and
temporal
variability
characterize
water
availablility.
Climate
change
m
y
exacerbate
such
variations.
Today
1
billion
people
lack
access
to
clean
and
abundant
drinking
water,
and
even
more
are
without
adequate
sanitation.
Adjustments
to
.'water
shortages
can
be
managed
where
physical
infrastructixe
(reservoirs,
pipelines,
and
canals)
and
water
management
institutions
exist.
Increasing
populations
dependent
on
limited
sources
served
by
isolated
systems
are
at
more
risk.
Landscapes
may
erode
or'
stabilize
as
precipitation
alters
vegetative
cover,
thus
affecting
runoff
,and
transport
of
sediment
and
pollutants.

Air
Pollution
I
..
..

The
sameindustrialprocessesthatproducegreenhousegases
will
alsoproduceincreased
urban
air
pollutants,
'and
they
too
can
pose
major
health
risks.
Levels
of
fine
particulates
(from
fossil
fuels
and.
wood
smoke)
and
ozone
(from
photochemical
reactions)
are
known
to
be
asocizted
with
highx
!z:
e!
s
of
hss?
itd
admissions
far
respirzttoq
diseases.
Fine
pahculates
also
appear
to'
be
associated
with
admissions
for
heart
'disease
and
with
general
mortality.
In
the
United
States,
where
air
pollution
is
relatively
low
.compared
with
Mexico
City
.and
some
Asian
cities,
it
nevertheless
contributes
to
70,000
excess
deaths
and
1
million
additional
hospitalizations
annually.
In
the
firture,
as
globalincreasesinenergyproductionlead
to
higherlevels
of
particulates,
andincreases
in
..
..
"

temper&
nd
ultraviolet
radiation
accelerate
the
reactions
that
produce
ozone
and
other
SecO
pollutants,
thehealtheffectsof
air
pohtion
on
aglobalscalecould
bestaggering.
E
temperatures
and
humidity
may
also
lead
to
higher
concentrations
of
plant
pollen
and
fungal
s
that
cause
allergic
disorders
such
as
asthma
and
hay
fever.

Weather
Disasters
and
Rising
Sea
Level
­

El
Nifio
is
associated
with
increased
rainfall
and
floods
in
some
regions.
Long­
term
cli~
change
over
the
entire
planet
may
result
in
an
increase
in
extreme
weather
events,
such
as
&OUC_

floods,
and
cyclones.
These
events
could
increase
the
number
of
deaths
and
injuries
and
the
incid;;
of
infectious
diseases
and
psychological
disorders,
as
well
as
causing
indirect
effects
thou&
f
shortages
and
the
proliferation
of
disease
vectors.
A
40­
centimeter
rise
in
sea
level
would
approximately
double
the
number
of
people
who
currently
exposed
to
flooding
each
year
in
areas
like
Bangladesh.
It
could
also
contribute
to
the
1
of
coastal
and
delta
farmland,
3
in
Egypt,
and
to
the
destruction
of
food
supplies.
Rising
sea
le
also
increases
the
vulnerability
of
costal
cities,
low­
lying
areas,
and
small
islands
to
damage
duri
storms.

Social
and
Demographic
Dislocations
,

­
Global
'
climatechangewouldalterpatterns
of
employment,
wealth
distribution,
ax
populationsettlementthroughouttheworld.
Physical.
conflictsmight
also
ariseoverdeplete
environmental
resources
such
ds
farmland,
surface
water,
and
coastal
fisheries.
Biodiversity
woul
also
be
affected
(see
Box
3).
The
greatest
destabilizing
effects
would
likely
be
experienced
in
areas
c
Africa
which
are
dready
highly
vulnerable.
At
the
same
time,.
populations
may
be
moving
out
o
L
'
How
climate
change
may
affect
health
DIRECT
EFFECTS
IErDIRECP
EFFEcrS
1
+
Y
?

FIGURE
3.
Ways
in
which
global
climate
change
may
affect
human
health.
(Adapted
from
IPCC,
1995)
­
i
..
/

.

tropicalandcoastal
areas
and
into
coolerwildernessareaswheretheywillbeexposedto
new
and
2.

Unfdar
health
threats.
From
anGther
point
of
view,
the
difficulty
of
responding
to
global
climate
change
lies
in
the
rapid
pace
of
the
change­
the
projected
rate
of
change
is
greater
than
has
occurred
on
earth
in
the
p
a
t
10,000
years.
Although
it
appears
that
some
of
the
global
climate
.changes
may
be
dealt
with
by
the
industrial
world,
adaptation
will
be
more
difficult
in
the
developing
world.
The
pace
of
global
climate
change
may
be
complicated
by
an
inadequate
pace
of
institutional
change.
8
POLICY
IMPLICATIONS
At
the
end
of
the
first
day
of
the
conference,
presentations
were
made
on
potential
policy
implications
for
health
surveillance,
diseaseprevention,
andhealthprofessionaleducation.
In
addition,
a
special
address
was
made
by
Briar@
twood,
administrator
of
the
Agency
for
International
Development,
on
"Implication's
for
InternationalCooperation"
(
seeBox
4).
Thesepresentations
served
as
background
and
introduction
for
the
breakout
and
working
group
panel
discussions
that
occurred
on
the
second
day;
infomiation
from
those'presentations
has
been
integrated
into
the
panel
reports
that
follow.

­
Panel
Reports
The
second
day
of
the
conference
wak
organized
around
six
concurrent
breakout
and.
working
group
panels
that
considered
the
policy
implications
of
global
climate
change
and
human
health.
The
six
panels
were:
(1)
Global
Surveillance
and
Response,
(2)
Disease
Prevention,
(3)
Education
for
the
Medicaland
Public
HealthCommunities,
(4)
InternationalCooperation,
(5
)
Researchand
Development
Needs,
and
(6)
Public
Outreach­
and
Risk
Communication.
These
panels
were
asked
to
work
fiom
the
assumptionthatglobalclimate
change
would
occur,
and
that
its
impacts
on
human
health
would
be
more
or
less
as
described
in
the
foregoing
,

discussion.
Working
from
.that
assumption,
the
panels
were
charged
with
addressing.
the
question,
.``
What
do
we
do
about
it?
'
That
is,
what,
strategic
actions
could,
and
should,
be
taken
to
anticipate
adverse
health
effects
before
they
occur
and
to
reduce
or
mitigate
those
effects
when
they
do
occur?
In
addition,
the
panels
were
asked
to
identify
both
short­
term
(1.
to
5­
years)
and
long­
term
(5
­
to
25
years)
strategies.
..

The
following
summariesreflecttheindividual
group
chairs'sense
.of
theparticipants'
discussion
in
their
respective
working
groups,
further
illuminated
by
the
material
presented
in
plenary
sessions
on
the
,.

..
..
..
.
Global
Surveillance
and
Response'

The
emergence
of
new
diseases
and
the
reemergence
of
familiar
diseases
represent
a
seric
threit
to
many
regions
and,
indeed,
.in
a
shrinking
world,
to
the
entire
human
species.
In
the
f~
ru
therefore,
it
will
be
criticaltohaveinplaceanintegrated,
worldwidesurveillance
and
respon
mechanism
for
emerging
infectious
diseases.
The
purpose
of
such
a
system
would
be
to
shorten
t:
timebetween
the
detectionofthefirst
caseand
theimplementation
of
effectivemeasures
f
treatment,
prevention,
andcontrol.
To
thedegreepossible,
therefore,
itshouldalso
i
n
c
h
surveillance
for
the
various
changes
in
climate
and
environment
that
may
provide
early
warning
sigr
of
the
possible
outbreak
of
dxease.
The
vitalelements
of
suchasystemare(
a)
arapid
and
comprehensivecommunicatior
network;
(b)
accurate,
reliable,
laboratory­
based
diagnosis
capabilities
in
host
countries
or
region:
centers;
and
(c)
a
mechanism
for
rapid
response.
The
functioning
of
this
system
would
also
be
aide
by
heightenedcooperation
among
nationalandinternationalhealthorganizations.
In
the
end,
th
,creation
of
an
integrated,
worlddde
system
to
monitor
the
occunence
and
emergence
of
diseas
could
become
the
most
important
international
health
policy
initiative
of
the
twenty­
first
century.
The
breakout
panel
reported
that
the
most
important
problem
in
this
area
is
the
creation
an(

maintenance
of
a
critical
mass
of
multidisciplinary
expemse.
Short­
term
strategies
to
address
thi:
problem
include
personnel
exchanges,
cross­
training,
a
d
the
establishment
of
a
Vice
Presidentia
Fellowship
Program.
Long­
Term
strategies
include
the
encouragement
of
multidiscipllllary
training
a
The
panel
also
endorsed
earlier
reports
calling
for
the
creation
of
an
international
consortium
toaddressclimate­
relatedissuej:
Onedifficulty
in
doingthisistheneedforpoliticalwilland
interagency
and
global
coordination.
A
short­
termstrategywouldlietocompiIeaninventory
of
existing
resources
and
facilities
that
might
become
part
of
the
effort,
including
sites
and
projects
studying
the
environment
and
climate
that
could
provide
remote­
sensing
data
and
other
indicators
for
health
surveillance.
There
was
no
consensus
on
which
agency
should
serve
as
the
focal
point
for
this
coordination
within
the
United
States,
although
the
Centers
for
Disease
Control
and
Prevention,
the
NAS,
the
IOM,
and
the
interagency
Committee
on
International
Science
Engineeringand
Technology
@art
of
NSTC)
were
offered
as
candidates.
There
was
agreement,
however,
that
the
United
States
could
not
carry
out
this
mission
alone;
it
will
be
necessary
to
work
with
the
resources,
facilities,
and
Finally;
the
importance
of
global
surveillance
and
response
was
discussed
as
being
critical
to
national
security
because
military
forces
might
need
to
be
deployed
to
virtually
any
area
of
the
world
on
short
notice.
Knowledge
of
emerging
diseases
and
their
potential
impact
on
rnih­
y
operations
is
of
great
importance
in
the
preparation
of
countermeasures
to
avoid
such
threats,
riduce
their
impact,
and
provide
a
rapid
response
to
outbreaks.
levels
of
relevant
fields.

.
I
institutions
of
other
countries
and
international
organizations.
:

3
Dr.
RuthBerkelman,
deputydirector,
NationalCenterforInfectious
Diseases,
Centers
for
Disease
Control
and
Prevention,
cochaired
this
panel
and
summarized
their
discussion
and
findings.

..
..
.
..

,.
..
~
."
­
'/
"

I
.I
.

S
U
M
W
Y
OF
THE
PROCEEDINGS
..
17
Strategies
(see
also
Table
3).
I
­
Short­
term
strategies:
Create
and
maintain
a
critical
mass
of
multidisciplinary
expertise.
Commission
the
NAS
or
the
IOM
to
conduct
a
study
of
the
problem.

Long­
term
strategies:

'
Encourage
multidisciplinary
training
at
all
levels
of
relevant
fields.

Disease
Prevention4
The
reemergence
in
the
Americas
of
infectious
diseases
that
had
been
controlled
in
the
past,
such
as
cholera,
plague,
and
dengue,
as
well
=@
e
emergence
of
new
infectious
agents,
such
as
Hanta
and
Guanarito
viruses,
E.
coli:
O:
157,
and
cgptosporidia,
have
had
a
direct
impact
on
health
policy
and
prevention
efforts.
Over
the
past
several
years,
governmental
and
nongovernmental
organizations
have
been
working
closely
to
modify
health
policy
to
place
more
emphasis
on
disease
prevention.
A
majorconcern
of
theseeffortsarethechangingdynamicsofdiseasetransmission,
which
are
.
influenced
by
migration,
land
use,
and
environmental
degradation.

any
response
will
be
flexible
management
within
the
health
sector
closest
to
the
viherable
population
to
allow
it
to
adapt
to
changing
patterns
of
disease.
In
addition,
the
wide
impact
of
infectious
diseases
such
as
AIDS
requires
a
policy
of
increasd
intersectorial
cooperation­
that
is,
there
must
be
fluid
and
open
communication
and
management
of
health
problems
among
health,
environmental,
and
agriculturalsections,
supportedbycompetentresearchthat
is
­basedoncarefulpolicyanalysis.
Participants
believed
that
policy
reform,
combined
with
broad
public
support
gained
by
effective
use
of
the
mass
media,
will
allow
us
to
confront
the
health
problepx
caused
by
global
climate
change
and
environmental
degradation.
Policies
for
disease
prevention
and
control
usually
involve
three
responses:
(1)
removal
of
the
hazardousexposure,
(2)
earlydetection(
andinvestigationoftheoccufrenceofdiseases),
and
(3)
,

treatmentandcontrolmeasures,
such
as
prophylactic
ther'dpy.
Primarypreventionmightinclude
vaccinating
children
or
draining
stagnant.
pools
where,
mosquitoes
breed.
In
dealing
with
the
health
effects
of
global
climate
bhange,
however,
it
would
require
preventing
and
even
reversing
greenhouse
warming
itself.
This
kind
of
"preprimary"
or
``
primordial"
prevention
would
be
desirable
but
was
beyond
the
scope­
of
this
conference.
Nevertheless,
there
are
still
many
actions
that
might
be
taken
to
mitigate
the
health
effects
ofglobalclimatechange,
especially
in
terms
of
anticipating
what
those
,

effects
will
be
and
which
populations
are
most
at
risk.
,Secondary
prevention
involves
surveillance
and
early
screening­
the
collection,
analysis,
and
dissemination
of
'pertinent
data­
and
tertiary
prevention
involves
responses­
plans
and
facilities
for
rapid
diqposis
and
effective
treatment
to
keep
a
disease
from
progressing.
Secondary
and
tertiary
Many
lines
of
action
are
being
examined
as
ways
to
prevent
diseases.
One'
requirement
for
.

4Dr.
Jonathan
Patz,
research&
ociate,
Johns
Hopkins
ichool
of
Public
Health,
cochairedthis
.
panel
ahd
summarized
their
discussionandfindings..
I
BOX.
3.
Ecology,
Epidemiology
and
Climate
Change'

Thomas
E.
Lovejoy
­
Smifhsonian
Institution
I
Altered
levels
of
greenhouse
gases
like
C02
constitute
an
important
environmental
change
by
themselves
in
addition
to
those
changes
driven
by
thealteredlevels.
Field
studies
of
the
effects
of
elevated
COz
on
natural
Communities
are
limited
at
this
point.
Bert
Drake'stwo­
speciesmarshcommunityatthe
Smithsonian
Environmental
Research
Center­
the
longest
running
field
experiment­
shows
that
plants
with
a
Cq
photosynthetic
pathway
(e.
g.,
a
sedge)
have
a'definite
competitive
edge
over
%­
pathway
species
(e.
g.,
a
grass),
Within
a
group
of
C4
or
C3
plants,
however,
it
is
not
possible
to
predict
in
advance
how
various
species
will
respond
to
higher
levels,
of
(2
0
2
.
An
initial
study
of
part
of
a
tree
subjected
to
2
months
of
elevated
C02
in
a
Panamanian
rainforest
ledtoyellowing
of
its
leaves
andreducedphotosynthesis.
It
appears
thattheexcessiveaccumulationof
carbohydrates
'
inhibits
photosynthesis,
with
consequent
high
irradiation
stress,
photodamage,
and
loss
ofchrdrophyll.
The
rest
of
the
tree
seems
incapable
of
drawing
off
the
excess
photosynthates.
This,
is,
of
course,
different
from
a
treeexperiencing
a
coz
increase
occurringover
yearsand
decades
or
a
tree
thatgrows
up
in
a
high­
C02
environment.
Of
course,
climate
change
willincludenotonly
C02
elevation
but
also
changes
in
temperature
regimes,
.rainfall,
and
other
hydrologicalpatterns.
There
are
almostnofield
experiments
yet
that
combine
more
than
a
single
one
of
these
factors.
Nonetheless,
it
is
clear
from
the
above
findings
that
it
is
a
mistake
to
think
of
elevated
C02
alone
as
a
benign
fertilizing
factor
for
plants.
Rather,
it
is
importanttorecognizethatelevated
C02
and
associated
climate
change
will
instigate
a
cascade
of
effects
that
will
ripple
through
natural
communities
withhard­
to­
en'visionepidemiological
consequences.
'

Paleoecologicalevidencerelating
to.
climatechange
during
glaciallinterglacial
swings
indicate
rates
of
dispersal
for
plant
species,
especially
trees,
that
are
much
slower
(l/
lOth)
than
those
projected
by
climate
models.
It
is
simply
not
­known
whether
species
couldmove
faster.
In
addition,
it
is
wellknown
in
NorthAmericaandEurope,
and
to
a
lesser
extent
in
the
less
studied
tropics,
that
biological
communities
disassembled
during
thoseclimate
changes
anddifferent
species
movedat
differentratesand
in
different
directions.
Ultimately,
species
assembled
in
communities
of
differentcomposition.
The
implications
for
epidemiology
are
difficult
to
envision,
although
worrisome.
.
'

Climate
change,
whether
human
or
naturally
driven,.
will
take
place
in
landscapes
that
have
been
highly
modified
by
human
activity.
This
,will
dramatically
lower
opportunities
for
dispersalandconsequentlygenerateconsiderableextinction
of
species­
that
is,
a
reduction
in
biological
diversity.
,
"
What
are
the
implications
for
human
.health?.
lt
is
hard
to
be
precise
ana
to
provide
a.
lot
of
detaif.
Nonetheless,
an
.abundance
of
changing
relationships
between
species
will
undoubtedly
affect
epidemiology.
Some
changes,
of
course,
may
bebeneficial,
but
the
balance
are
likelyto
be
detrimental
because
weedy
species
such
as
white­
tailed
deer
will
be
favored
overnonweedy
species.,
It
seems
reasonable
to
anticipate
epizootics
and
epidemics
without
any
precedents.
In
addition,
loss
of
biodiversity
wi!!
impoverish
the
potentialofbiotechnology
to
contribute
to
the
wealth
of
nationsand
willsimilarlydiminishthepotential
of
thelife
sciences
to
contribute
to
human
health,
weaith,
and
well­
being.

*Excerpts
from
a
special
briefingat
the
Conference
onHumanHealthandGlobal
Climate
Change,
September
I
I
,
1995.
SUMMARY
OF
THE
PROL
DINGS
19
preventionstrategies
are
needed
in.
most
if
notallnations.
However,
thecreation
of
aglobal
+.

surveillance
and
response
capability
will
require
unprecedented
international
'collaboration,
including
'
a
softening
of
the'
traditional
boundaries
between
sectors,
agencies,
and
nations.
Nongovernmental
organizations
and
the
media
also
have
a
important
role
to
play
in
educating
the
population,
without
frightening
them,
and
possibly
changing
some
of
theirmoredestructivebehaviors(
see
'
"Public
Outreach
and
Risk
Communication,"
p.
24).
The
breakout
group
recommended
that
prevention
activities
focus
on
anticipatory,
rather
than
reactionarymeasures.
It
identifiedsixpriorityareasthatoverlapandincorporatethose
of
other
breakout
groups:

1.
targeted,
integrated
nuveillance
thatfocuses
on
transitionalzonesandvulnerable
2.
changes
in
medical
education
that
incorporate
environmental
health
into
curriculum
and
3.
international
cooperation
through
information
sharing
and
surveillance
networks;
4.
methodologicalresearch
toevaluatepreventionandinterventionprogramsandto
5.
public
education
and
outreach
aimed
at
policymakers
as
well
as
vulnerable
popu­
lations,

6.
public
health
inffastruchlre
toconduct(
a)
researchand
(b).
vaccineand
expome
populations;

board
u
identify
vulnerable
populations,
transition
areas,
and
other
risk
factors;

especially
children
and
the
elderly;
and
reduction
programs.
­.

e
.

Strutegies
(see
also
Table
i
.
3).

Short­
term
strategies:
Compile
'an
inventory
of
existing
resources
and
facilities
to
study
the
environment
and
climate
that
could
provide
remote­
sensing
data'and
other
indicators
for
health,
surveillance.

Long­
termstrategies:
'
.
Refocus
or
develop
the
public
health
infrastructure.
..

Education
for
the'hedical
and
Public
Health
Communities5
Despite
increasing
evidence
that
global
climate
change.
and
ozone
depletion
may
have
serious­
consequences
for
human
health,
there
is
little'
understanding,
both
among
policymakers;
and
the
public,
of
the
extent
of
this
potential
threat.
Physicians
and
public
health
professionals
should
be
central
figures
in
helping
to
promote
an
understanding
of
the
health
effects
associated
.w
i
t
h
climate
change,
but
they
are
by
and
large
uninformed
about
the
topic,
as
their
education
does
not,
.in
general,
cover
the
relationship
o
f
global
environmental
change
to
h
u
m
.
healtin.
I
,
..

'Dr.
Max
Lum,
director,
Office
of
HealthCommunications,
NationalInstitute
of
Occupational
Safety
and
Health,
cochaired
this
panel
and
summarized
their
discussion
and
findings.

..
I
..
.
..
20
­

I
.
,­.
CONFERENCE
ON
HUUdN
fF
I
TH
A
flD
GLOBAL
CLIM
TE
CHANGE
,I
Physicia,
J,
nurses,
and
other
health
professionals
have
a
vital
role.
to
play
in
responding
tb
the
health
effects
of
global
climate
change.
At
present,
however,
physicians
donotreceiveadequate
training
in
occupational
and
environmental
medicine,
much
less
in
the
medical
problems
arising
from
.
global
climate
change,
such
as
tropical
diseases
appearing
in
ternperature
zones.
In
the
United
States,
for
exbple,
although
two­
thirds
of
medical
schools
include
occupational
and
environmental
hed&
in
their
curricula,
the
average
student
receives
only
6
hours
of
exposwe
to
these
subjects
over
4
years
of
study.
The
situation
is
somewhat
better
in
schools
of
public
health.
Yet
for
both
medical
and
public
health
students
in
the
United
States
there
is
essentially
no
time
available
in
the
curriculum
to
address
thepotential
human
healthconsequencesofglobalclimatechange.
Formostprofessionalstheir
principal
source
of
information
on
global
environmental
health
are
articles
in
the
scientific
literature
and
conferences
sponsored
by
nonprofit
organizations.
The
breakout
group
agreed
that
health
professionals
should
play
a
critical
role
in
addressing
the
health
effects
of
global
climate
change.
The
central
questions
panelists
posed
were
(a)
what
do
health
professionals
already
know,
(b)
what
do
they
want
to
know,
and
(c)
what
should
they
know.
As
a
short­
term
strategy,
the
group
re3ommended
that
the
IOM
and
NAS
conduct
a
study
to
identify
core
competencies
and
training
mechanisms
in'the
area
of
human
health
effects
of
global
climate
change,
similar
to
a
recent
IOM
study
of
environmental
medicine
(1995).
Global
climate
and
health
issues
should
be
incorporated
into
medical
board
exams,
reflecting
the­
importance
of
this
subject
for
the
training
of
physicians.
The
IOM
and
NAS
might
also
broker
efforts
to
promote
faculty
development
in
this
area
and
to
create
centers
of
excellencein
medical
schools
that
would
develop
curricula
in
huinan
health
and
global
climate
change.
The
group
also
recommended
conducting
a
study
to
identify
existing
government
and
indytry
progrzms
that
protect
workers
from
the
effects
of
ultraviolet
exposure.
Such
an
activity
could
also
increase
awareness
of
the
h
v
d
s
of
stratospheric
ozone
depletion.
These
effortsshould
be
cbordinated.
withthose
of
professional,
educational,
andpublic
service
organizations.
Health
professionals
should
also
help
in
developing
educational
materials
and
in
presenting
information
to
policymakers
and
the
general
public
to
help
increase
understanding
of
.'
thehealthimplicationsofenvironmentalpolicies.
Theseeffortsshouldincludethespecialneedsof
populations
such
as
migrant
workers
and
minorities
that
might
not
have
adequate
access
to
health
care
information.
In
the
long
term,
it
will
be
important
to
monitor
the
effectiveness
of
these
and
other
programs
and,
more
importantly,
to
disseminate
their
results.

Strategies
(see
also
Table
3).

Short­
term
strategies:
Y
.
Have
the
IOM
or
NAS
conductastudy
to
­identify
corecompetencie$.
andtraining
mechanisms
in
thearea
of
globalenvironmentalhealth,
similartoarecent
IOM
studyof
environmentalmedicine.
f
Identify
and
study
*existing
government
and
industry
programs
designed
to
protect
workers
from
the
effects
of
exposure
to
the
sun.
'
.­
.
'
/
,..,

BOX
4.
Implications
for
international
Cooperation*
Brian
Atwood
U.
S.
Agency
for
lnfernafional
Development
­

By
workingclosely
with
ourdevelopingcountry
partners,
the
U.
S.
Agency
for
International
Development
is
able
to
facilitate
the
subtle
but
critically
important
changes
that
raise
awareness
of
the
threats
of
climate
change
andhelp
to.
shape
preventative
and
responsive
measures',
Our
work
has
informed
other
donors
and
encouraged
them
to
invest
in
solutions
we
need.
Developingcountries
in
particular
are
.
on
the
precipiceofglobal
environmental
change.
Theysoon
will
be
the
leading
source
of
greenhouse
gas
emissions,,
and
the
resultingclimate
change
will
take
a
heavy
toll
on
theircrowded
coastal
areas
and
fragile
ecosystems.
Theextraordinarybiologicalwealth
of
these
countries
is
already
threatened
by
poorly
planned
development
that
undercuts
the
natural
capital
they
and
we
need
for
the
future.
9
Energy
consumption
and
one
of
its
unwelcomeby­
products,
pollution
in
the
formof
carbon
emissions,
are
growing
fastest
in
developingcountries
and
in
countries
whose
economies
are
in
transition.
Developingcountries
are
also
experiencingrapid
rates
of
deforestation
and
ecosystem
degradation,
which
'eliminates
a
primary
sink
for,
greenhouse
gases.
For
example,
over
the
last
decade,
154
million
hectares
of
tropical
forests,
equivalent
to
more
than
three
times
the
land
area
of
France,
have
been
lost
to
other
uses.
The
rate
of
that­
loss
of
biomass,
especially
in
developing
countries,
is
alarming.
The
resultingenvironmental
degradations
and
misuse
ofnatural
.resources
create
opportunities
for
new
diseases,
or
old
ones,
to
takehold.
We
use
the
phrase
"emerging
diseases,"
yet
for
millions
of
people.
the'new
viruses
have
already
emerged,
and
they
have
already
claimed
the
lives
of
loved
ones.
The
word"
emerging"
simply
does
not
convey
the
urgency
we
sense.
Only
yesterday
we
were
convinced
that
science
had
overcome
the
assault
of
these
infectious
diseases.
Advances
in
antibiotic
drugs,
vaccines
against
childhood
diseases,
and
improved
sanitation
technology
all
seemed
to
be
winning
the
day.
The
incidence
of
polio,
whooping
cough,
and
diphtheria
were
declining.
Fast­
acting
antibiotics
reduced
the
threat
of
meningitisandbacterialpneumonia.
'
But
we
nowknow
that
our
euphoria
was
premature.
We
did
not
take
into
account
the
extraordinary
resilience
of
infectious
microbes,
which.
have
a
remarkable
ability
to
evolve,
adapt,
and
develop
resistance
to
drugs.
Thus,.
diseases
that
were
once
thought
to
be
under
control
have
reemerged.
There
are
many
of
these
reemerging
diseases,
andthey
just
do
not'
appear
only
in
the
developingwodd
nowadays.
We
find
them
in
NewMexico,
in
Minnesota,
in
Virginia,
and
in
New
York.
Around
the
world
there
is
a
resurgence
of
cholera,
malaria,
and
yellow
fever,
often
in
drug­
resistant
forms.
And
of
course,
there
is
HIV
and
AIDS.
We
believe
that
global
problems
must
be
resolved
at.
the
local
level.
We
know
that
'these
efforts
must
be
aided
by
new
breakthroughs
in
science
and
technology.
Investment
in
research
is
essential
if
we
are
to
keep
up
with
the
effects
of
ecological
change.
The
battles
we
must
fight
against
new
microbes,
new
forms
of
crop
blight,
the
spread
of
desertification,
new
forms
of
pestilence,
and
the
rapid
population
growth
make
research
more
important
than
ever.
;

VJa
face'a
dynamic,
rapidly
accelsr?!
ing
set
of
n
w
challenges,
yet
we
are
at
risk
of
falling
desperately
behind
the
curve,
as
the
changes
we
advertently
and
inadvertently
introduce
run
far
ahead
of
our
resources
and
our
knowledge
base.
Research
is
not
like
tap
water.
It
cannot
be
turned
off
and
on
again
without
serious
consequences.
To
be
successful
in
these
efforts,

Conjiriued
'Excerpts
from
remarks
at
the
Conference
on
Human
Health
and
Global
Climate
Change,
September
11,
1995.
22
.
­.
y­.

CONFERENCE
ONHUMANF.
LTHAND
GLOBAL
CLIMATE
c
m
c
BOX
4.
C­
otinued
governments
must
continue
their
support
Of
t
h
e
scientific
community.
This
will
require
considerable
efforts
by
federal
agencies,
by
our
university
partners,
and
by
nongovernmental
organizations.
The
private
sector
is
our
natural
partner.
However,
it
does
not
cover
the
entire
I
t
is
dangerous
to
assume
that
the
unfettered
hand
of
Adam
Smith
will
lead
to
the
investments
we
need
to
deal
with
international
health
and
environmental
threats
to
the
United
States.
That.
will
require
a
coherent
and
cost­
effective
foreign
assistance
program
backed
by
sound
policies
and
global
cooperation.
We
are
uniquely
placed
as
a
nation
to
help
the
rest
of
the
world
meet
these
challenges.
Our
quality
of
fife
in
the
next
century
will
be
determined
in
large
measure
by
how
we
meet
the
global
challenges
of
today.
Science
and
technology
give
u
s
t
h
e
tools
we
will
need
to
meet
the
challenges
of
tomorrow.
a
spectrum
of
research.

%

3
Long­
term
strategies:
Monitortheeffectivenessoftheseandotherprogramsand,
moreimportantly,
dissem­

Incorporate
questions
about
climate­
related
health
issues
on
medical
board
examinations.
inate
their
results.

­
International
Cooperation6
Global
climate
change
is
.bqlieved
to
cause
a
wide
variety
of
deleterious
effects
including
desertification,
changes
in
agricultural
patterns,
and
disease.
These
effects
are
both
direct
and
indirect,
and
the
causes
may
be
either
nahiral
or
manrnade.
TO
the
extent
that
global
climate
change
and
its
impacts
are
influenced
by
human
activity,
methods
must
be
found
to
mitigate,
adapt
to,
or
respond
to
them.
The
U.
S.
govemment
3s
obligated
to
exercise
leadership
at
home
and
abroad
to
ensure
that
responses
are
appropriate
and
timely.
.Every
human
being
is
vulnerable
to
the
effects,
of
global
climate
change,
but
the
citizens
of
developing
countries
and
regions
face
the
most
immediate
dangers.
In
those
areas,
both
climatic
change
and
the
need
for
responses
to
it
'may
be
greatest,
but
the
available
resources
for
addressing
.'
them
is
most
limited.
Clearly,
thepreventiveandresponsivemeasuresweusetodealwith
global
climate
change
and
its
effects
must
involve
every
affected
person
.and
operate
society­
wide.
The
breakoutpanelreportedthatmany
of
thenecessarysystems
.
andnetworksfor
.
internationalcooperationarealreadyin
place­
theUnitedNationsEnvironmentalPrQgrarnme,
the
World
Health
Organization,
UNICEF,
and
networks
of
collaborating
centers.
WhaGis
required
is
improved
coordination
among
existing
systems
to
place
the
health
effects
of
global
climate
change
on
their
respective
agendas
and
to
ensure
a
two­
way
flow
of
information
among
them.
The
panel
found
a
particular
need
to
.
improve'.
thelinksbetweenagenciesandorganizationsthatconductclimate
forecasting,
health
planning,
health
surveillance,
and
the
implementation
of
health
pro,
gniis.

I
I
I
6
Dr.
Rudi
Slooff,
Division
of
Environmental
Health,
World
Health
Orgkization,
cochaired
this
­panel
&d
summariz.
ed
their
discussion
and
findings.
,
­.
,/
I
\

'
.
.4
.
S
U
M
M
Y
OF
THE
PROCi?,
JNGS
23
One
short­
term
strategy
would
be
to
incorporate
health
effects
monitoring
and
reporting
into
existingglobalclimatechangeactivities,
such
as
theFrameworkConvention
on
ClimateChange
$o
g
m
and
the
Uiited
Nations­
sponsored,".
Climate
Agenda."
Another
strategy
would
be
to
look
for
the
health
effects
of
global
climate
change
in
the
information
already
gathered
for
the
ongoing
U.
S.
Country
Study
Program.
These
efforts
will
be
ineffective,
however,
unless
they
are
accompanied
by
increased
efforts
to
provide
relevant
infomation
to
national
and
international
policymakers.
In
the
long
term,
the
panel
recommended
that
global
climate
change
and
health
issues
be
incorporated
into
sustainable
development
planning,
not
only
by
individual
nations,
but
also
by
the
World
Bank,
the
United
Nations
Development
Program,
the
Food
and
Agriculture
Organization,
and
similar
organizations.
By
the
same
token,
health
and
climate
planning
should
be
broadened
to
include
"

related
environmental
issues
such
as
biodiversity.
This,
in
turn,
requires
that
stakeholders
have
better
accessto
the
information
gathered,
analyzed,
anddisseminatedbytheglobalsurveillancesystem
discussed
by
other
breakout
panels.
.3
Strategies
(see
also
Table
3).

Short­
term
strategies:
Incorporatehealtheffectsmonitoringandreportingintoexistingglobalclimatechange
Look
for
the
health
effects
of
global
climate
change
in
the
information
already
gatherzd
programs.

for
other
programs.

.
Long­
termstrategies:
Incorporate,
globalclimate
.
changeandhealth
.
issuesintosustainabledevelopment
planning,
not
only
by
individualnations,
butalsobytheWorld
Bank,
theUnitedNations
Development
Program,
the
Food
and
Agriculture
Organization,
and
similar
orgapizations.

.
Broaden
health
and
climate
planning
to
include
environmental
issues
such
as
biodiversity.

Research
and
Development
Nee&
'

Rather
than
enumerate
the
many
specific
research
topics
that
need
to
be
addressed,.
the
breakoutpanelemphasizedtheneed
for,
an
integrated,
interdisciplinary
R&
D
program
that
will
encourage
collaboration
among
experts
and.
organizations
from
a
wide
range
of
fields
and
disciplines.
Achieving
this
will
probably
require
a
concerted
effort
to
overcome
the
boundaries
that
Currently
ieparate
scientificdisciplines,
researchinstitutions,
budgetaryprograms,
h
d
i
n
g
agencies,
and
internationalsponsors.
IntheUnitedStates,
forexample,
fundingwouldprobablycome
from
a
consortium
of
federal
agencies
rather
than
from
a
series
of
small,
fragmented
programs.
The
researchproblemsaddressedbythisprogramshouldincludeclimaticvariationsthat
already
pose
health
risks,
as
well
as
future
effects
of
global
climate
change.

..

'Dr.
David
Rall,
foreign.
secretaq,
Institute
of
Medicine,
cochaired
this
panel
and
summarized
their
discussion
and.
findings.

..
..
..
..
..
I
.

..
I
.
%.
..
.
­.
.
..
.
.
..
..
/

"
.
I
/`
,­,

CONFERENCE
ONKUMAN
HEALT
1~~
GLOBAL
CLIMATE
CHANGE
24
Strategies
(see
also
Table
3).

Short­
term
strategies.
In
the
short
term,
the
panel
proposed
that
the
program
undertake
pdot
projects
involving
c
a
e
studies
that
integrate
three
sets
of
variables:

1.
infectious
diseases
(e.
g.,
cholera,
dengue,
malaria,
and
Lyme
disease);
2.
mechanisms
ufmcqtibilily
(e.
g.,
W­
B
and
immune
suppression,
fine
pdcdates,
and
3.
global
change
driyers
that
might
exacerbate
or
mitigate
these
problems
(e.
g.,
population
cardiovascular
or
pulmonary
disease);
and
growth,
economic
development,
and
urbanization).

­
Possible
models
for
these
case
studies
are
the
Technical
and
Scientific
Assessment
and
the
United
Nations
Intergovernmental
Panel
on
Climate
Change.
The
case
studies
themselves
could
be
performed
by
international
organizations,$
y
private
groups,
or
by
the
IOM
or
NAS.
.

Long­
term
strategies.
The
long­
termgoals
of
thisprogram
wouldbeto
identify
andaddressgaps
in
current
..

knowledge,
and
to
disseminate
and
apply
the
lessons
learned
from
the
case
studies;
­

Public
Outreach
and
Risk
Communication`

Despite
a
wealth
of
scientific
&dies
and
technical
information,
the
general
public
is
not
well
informed
on
the
relationship
between
global
climate
change
and
human
health.
Several
participants
made
the
analogy
to
the
difficulties
of
informing
the
public
about
the
dangers
of
nuclear
war:
Such
information
is
highlytechnical,
far'
removed
from
thecommonexperience,
disconcerting
to
contemplate,
and
often
undermined
by
a
vocal
opposition.
AS
a
result,
the
first
step
in
any
outreach
campaign.
would
be
to.
assess
the
information(
anddisinfonnation)
that
is
alreadyavailable
to
determine
what
further
steps
might
be
appropriate.
The
breakout
panel
endorsed
the
principles
of
risk
communication
that
are
embodied
in
the
10­
step
strategy
outlined
in
Table
2.
The
primary
long­
term
goals
ofihis
strategy
are
(1)
involving
the
public
by
encouraging
awareness'
and
discussion,
and
(2)
building
.bridges
between
the
medical
and
environmentalcommunities.
In
bothcases,
the
panelrecommended
working
through
existing
nemorks
and
infrastructures,
initially
targeting
opinion
leaders
but
making
use
of
the
full
range
of
formal
and
informal
intermediaries
to
reach
broader
audiences­
not
only
churches
ana
newspaper
eilitors,
`for
example,
but
also
Boy/
Girl
Scouts
andtelevisionweathemeri,
as
well
as
medical
associations,
senior
citizens'
aisociations,
and
schools.

.
Dr.
William
Farland,
director,
National
Center
for
Environmental
Assessment,
Environmental
8
Protection
Agency,
cochaired
this
panel
and
summarized
their
discussion
and
findings.

I
..

..
/

I'
,/
'
,­.

S
U
~~R
Y
OF
THE
PROCET
{V
G
~
r?

TABLE
2.
Developing
a
Risk
Communication
Strategy
for
Global
Climate
Change
25
Step
1:

Step
2:

,
Step
3:

Step
4:

Step
5:

Step
6:

Step
7:

Step
8:

Step
9:
.Review
background
information.
(What
messages
are
already
out
there?)

Set
communication
objectives.
(What
do
we
want
to
accomplish?)
Example:
Increase
public
awareness
about
the
public
health
implications
of
global
climate
change.

Analyze
and
segment
target
audiences.
(Whom
do
we
want
to
reach?)
Example:
Construct
communications
based
on
audience
attitudes.

Develop
and
pretest
message
concepts.
(What
do
we
want
to
say?)

Select
communication
channels.
(Where
do
we
want
to
say
it?)

Create
and
pretest
messages
and
produd'.
(How
do
we
want
to
say
it?)

Develop
a
promotion
plan.
(How
do
we
get
it
used?)

Implement
communication
strategies
and
conduct
a
process
evaluation.
(Let's
do
it!)

Conductoutcomeandimpactevaluations.
(How
well
did
we
do?)
.
..

Step
10:
Feedback
to
improve
communication
effectiveness.
(Wheredowe
go
from
here?)
­

Strategies
(see
alsoTable
3).
The
panelideritifiedthefollowingshort­
termactionitems,
which
might
serve
as
the
foundation
for
long­
term
efforts:
...

Identify,
contact,
.
andinfuseexistingnetworkswithhealth.
concernsrelatedtoglobal
climate
change.
Use
these
networks
as
a
feedback
mechanism
to
find
out
what
further
information
the
public
or
needs.
t
Distilltheinformationgenerated
by
thepresentconference
for
dissemination
through
joumal
articles,
editorials,
op­
edpieces,
targetedbrochures,
publicserviceannouncements,
informational
videos,
or
a
home
page
on
the
World
Wide
Web.

.
Establish
a
volunteer
group
or
fonun
to
continue
the
communication
activities
suggested
or
actually
begun
during
the
present
conference.
Develop
a
response
capability
to
counter
disinfomtion.

..

.I
..
..

....
."
..
Participants
voiced
a
clear
message
throughout
the
conference:
Changes
in
global
climate
their
efforts
would
help
mobilize
opinion
and
action
toward
the
implementation
of
strategies
that
would
occur
'as
far
"upstream"
as
possible.
'

Confermce
participants
identified
and
described
a
number
of'actions
that
could
be
taken
to
address
these
potential
threats.
These
strategies
are
summarized
in
Table
3
and
share
certain
common
threads:
e
would
pose­
substantial
risks
to
h
k
a
n
health,
both
in
the
near
andlong­
term.
They
also
hoped
that
'identify
and
work
with
existing
resources,
facilities,
networks,
and
information;
encouragegreatercoordination
and
collaboration
amoqg
relevantorganizations,

create
from
these
institutions
and
funding
sources
an
integratedworldwidenetworkfor
support
multidisciplinaryresearchtodeterminelinkagesamongglobalclimatechange,

provideappropriatetraining
for
researchers
and
healthprofessionals,
includingthe
establishinformation
and
outreachprograms.
­
disciplines,
nations,
and
funding
agencies;

surveillance
and
response
to
indicators
o@
lobal
climate
change
and
emerging
diseases;

food
production,
and
human
health;

creation
of
centers
of
excellence
and
the
enhancement
of
faculty;
and
.­
0
E
a
3
c
a
*

d
a
­
­
c
c
27
i
I­
­
i
References
and
Further
Reading
I
The­
interestedreadercan
find
more
detailedinformationaboutthetopicscovered
by
&is
conference
by
referring
to
the
following
publications:

Centers
for
Disease
Control
and
Prevention.
1994.
Addrasing
Emerging
Infectious
Disease
Threats:
A
Prevention
Strategy
for
the
United
Stata.
Atlanta:
CDC.
Chivian,
Eric,
Michael
McCally,
Howard
Hu,
and
Andrew
Haines
(eds.).
1993.
CriticaZ
Condition:
Human
Health
and
the
Environment.
Cambridge,
MA:
MIT
Press.
CISET(
Committeeon
International.
Science,
Engineering,
andTechnology)
WorkingGroup
on
Emerging
and
Re­
emerging
Infectious
Diseases.
1995.
h.
fectious
Diseme:
A
Global
Health
Threat.
Washington,
DC:
National
Science
and
Technology
Council.
Epstein,
Paul
R
1995.
Course
Reader:
Global
Climate
Change,
Ecology
and
Public
Health.
Prepared
for
the
NSTC­
IOM
Conferencan
HumanHealthandGlobalClimateChange,
11­
12
September
1995.
IOM
(Institute
of
Medicine).
1995.
Environmental
Medicine:
Integrating
a
Missing
Element
into
Medical
Education.
Andrew
M.
Pope
and
David
L.
Rall
(eds.).
Washington,
DC:
National
Academy
Press.
IOM.
1992.
EmergingInfections:
MicrobialThreats
to
HealthintheUnitedStates.­
Joshua
Lederberg,
Robert
E.
Shope,
andStanley
C.
Oaks,
Jr.
(eds.).
Washington,
DC:
National
Academy
Press.
IPCC
(Intergovernmental
Panel
on
Climate
Change).
1995;
Climate
Change
199.5:
Impacts,
Adapta­
tions
andMitigatiun
of
ClimateChange:
Scienhpc­
Technical
Anabsa.
Contribution
of
WorkingGroup
I1
to
theSecondAssessmentReportoftheIntergovernmentalPanelon
ClimateChange.
.
Watson,
R.
T.;
.M.
C.
Zinyowera,
and
RH.
Moss
(eds.).
'
Cambridge:
CambridgeUniversityPress.
.
McMichael,
Anthony
J.
1993.
Planetary
Overload:
Global
Environmental
Change
and
the
Health
of
the
Human
Species.
Cambridge,
UK:
Cambridge
University
Press.
Michael,
E.,
and
D.
A.
P.
Bundy.
1995.
The
global
burden
of
lymphatic
filariasis.
In:
World
Burdei
of
Diseases.
C.
J.
L.
Murray
and
A.
D.
Lopez
(eds.).
World
Health
Organization,
Geneva.
NationalResearchCouncil.
1989.
Improving
Risk.
Communication.
'
Washington,
DC:
National
Academy
Press.
UnitedNationsEnvironmentalProgram.
i994.
Environmenful
Efects
of
OzoneDepletion:
1994
Assessment.
Nairobi,
Kenya:
UNEP.
Wilson,
Mary
Elizabeth,
Richard
Levins,
and
Andrew
.Spielman
(4s.).
1994.
Diseuse
in:
Evolution:
Global
Changes
and
Emergence
of
Infectious
Dbeam.
Albany:
NewYork
Academy
of
Sciences.
WHO
(World
Health
Organizkon).
In
press.
ClimateandHeaith
iri
a
Changing
World.
Geneva:
WHO.
WHO.
Ant'lmny
J.
Mc?
kichsd
st
d.
.(&.).
i
n
press.
Human
Hea!
th
and
Global
Climate
Change.
Geneva:
WHO.
WHO.
1995.
Action
Planfor
Malaria
.Control
1995­
2000.
Unpublished
document.
'
WHO.
1995.
Chaga.
sDisease:
Important
Advances
in
Elimination
of
Pansmission
in
Four
Countn'es
28
.,

in
Latin
America.
WHO
Press
Office
Feature
No.
183,
Geneva:
WHO.

\

..
..
..
..
,.
..

..
,
.
,I
,
:­,

.REFERENCESAND
FURTF'
.
~~
EADING
WHO.
1994.
Progress
Report
Control
document.
.
,/
'
..­.

29
of
Tropical
Diseases
(CTD/
MIP/
94.4).
Unpublished
,WHO.
1990.
Potential
Health
Eflects
of
Climatic
Change.
Geneva:.
WHO.

3
..

..
I
.

..
_.
.

APPENDMA
,/
'
­.

­
National
Science
and
Technology
Council
(NSTC)
Sponsoring
Members,
Interagency
Working
Group,
Institute
of
Medicine
@OM)
Steering
Committee,
and
Staff
NSTC
SPONSORING
MEMBER
AGENCIES
Centers
for
Disease
Control
and
Prevention
National
Science
Foundation
Environmental
Protection
Agency
.4
.
Pan
American
Health
Organization
National
Aeronautics
and
Space
U.
S.
Department
of
Agriculture
Administration
U.
S.
Department
of
Defense
National
Institutes
of
Health
U.
S.
Department
of
Energy.
~,

National
Oceanic
and
Atmospheric
U.
S.
Global
Change
Research
Program
Administration
U.
S.
A
g
e
n
c
y
f
o
r
International
.
.

Development
.
'
­

.
NSTCINTERAGENCY
WORKING
GROUP
Maurice
Averner,
Advanced
Life
Support,
Life
and
Biomedical
Sciences
and
Applications
Division,
National
Aeronautics
and
Space
Administration,
Washington,
DC
Lois
Beaver,
Office
of
Extemal
Affairs,
Food
and
'Drug
Administration,
Rockyille,
MD
Rosina
Bierbaum,
Environment
Division,
Office
of
Science
and
Technology
Policy,
Executive
Office
of
the
President,
Washington,
DC
,

Jim
Buizer,
Office
of
Global
Programs,
National
Oceanic
and
Atmospheric
Administration,
Silver
Spring,
MD
Dennis
Carroll,
Office
of
Health
and
Nutri­
tion,
Agency
for
International
Development,
Washington,
DC
Jack
C..
Chow,
Division
of
International
Relations,
Fogarty
International
..

..
..
'
\'

..
.
.­
.
~
'
..
..
..
..
.
~.
..
Center,
National
Institutes
of
Health,
Bethesda,
MD
Robert'
Corell,
Geosciences
Division,
..
National
Science
Foundation,
Arlington,
VA
..

Jackie
Dupont,
Agricultural
Research
Service,
U.
S.
Department
of
Agriculture,
Beltsville,
MD
Elaine
Esber,
Center
for
Biologics
Evalua­
tion
and
Research,
Food
and
Drug
.
Administration,
Rockville,
MD
Gary
Evans,
Office
of
the
Secretary,
U.
S.
Department
of
Agriculture,
Washington,
DC
Mike
Finley,
Office
of
External
Relations,
'Pan
American
Health
Organization,
Washington,
DC
Karen
Gallegos,
Office
of
Global
Programs,
U.
S.
Department
of
State,
Washing­
ton,
DC
.
..

..

31
..

..
..
.

­.
..
..
..
_.
.
­.:
,:.
Luiz
Galvao,
Division
of
Health
and
Envi­
­
ronment,
Pan
American
Health
Organization,
Washington,
DC
Mary
GantYNational
Institute
of
Environ­
mental
Health
Sciences,
National
Institutes
of
Health,
Bethesda,
MD
Ann
Grambsch,
Climate
Change
Bureau,
Office
of
Policy,
Planning,
and
.

Evaluation,
Environmental
Protection
Agency,
Washington,
DC
Duane
Gubler,
Vector
Borne
Infectious
Diseases
Division,
Centers
for
Disease
Control
and
Prevention,
National
Center
for
Infectious
Diseases,
Fort
Collins,
CO
3
Debbie
Hanfman,
Science
Division,
Office
o
f
Science
and
Technology
Policy,
Executive
Office
of
the
President,
Washington,
DC
cal
Research
and
Materiel
..
Command,
Ft.
Detrick,
MD
Carla
Kappell,
Office
of
Energy,
Environ­
Col.
Jerry
Jam,
United
States
Amy,
Medi­

ment,
and
Technology,
Burequ
of
Global
Programs,
Field
Support,
and
Research,
Agency
for
International
Development,
Washington,
DC
Hiram
Larew,
Office
of
Policy
and
Evalua­
tion,
Agency
for
International
Development,
Washington,
DC
Orville
Lavander,
Nutrient
Requirements
and
Functions
Laboratory,
Agricultural
Research
Service;
U.
S.
Departkent
of
Agriculture,
.
'

Beltsville,
MD
nology
and
Health,
U.
S.
Department
of
State,
Washington,
.DC
Ed
Malloy,,
Office
of
Science,
Technology,
and
Hea1th;
U.
S.
Department
of
State,
Washington,
DC
.
'
.
Alexandra
Leviti,
Office
of
Science,
Tech­

.,
,.
.

..
..
.
..
..
..
..
:.
q
Patrick
McConnon,
Centers
for
Disease
Control
and
Prevention,
Atlanta
Mike
McCracken,
US.
Global
Change
Research
Program,
Washington,
DC
Roscoe
M.
Moore,
Development
Support
and
African
Affairs,
Office
of.
International
Health,
U.
S.
Department
of
Health
and
Human
Services,
Rockville,
MD
Jonathan
Patz,
Johns
Hopkins
School
of
Public
Health,
Environmental
Protection
Agency,
Office
of
Policy,
Planning,
and
Evaluation,
Climate
Change
Division,
­Washington,
DC
Karen
Peterson,
Division
of
,International
Relations,
Fogarty
International
Center,
National
Institutes
of
Health,
Bethesda,
MD
Hemah
Rosenberg,
Office
of
External
Re­

'
lations,
Pan
American
Health­
Organization,
Washington,
DC
David
Sandalow,
Council
on
Environmental
Quality,
Executive
Office
of
the
President,
Washington,
DC
Joel
Scheraga,
Climate
Change
Bureau,
Office
of
Policy,
Planning,
and
Evaluation,
Environmental
Protection
Agency,
Washington,
DC
Artie
Shelton,
Office
of
Allergy,
Immunol­
ogy
and
Oncology,
U.
S.
Department
of
Veterans
.Affairs,
Washington,
DC
Phillip
L.
Sims,
Agriculture
Research
Ser­

­
vice,
U.
S.
Department
of
­
,

.Agriculture,
Beltsville,
MD
Anthony
Socci,
U.
S.
Global
Change
Re­
search
Program,
Washin$
on,
DC
Macol
Stewart,
Office
of
Global
Programs,
National
Oceanic
and
Atmospheric
Administration,
Silver
Spring,
MD
Col.
Ernie
Takafkji,
U.
S
Army
Medical
Research
Institute
for
Infectious
Diseases,
Fort
Detrick,
MD
,.

..

..
.
,.
.
..
.
...
..
.

..
..
.
..
..
~.
/
i­.
.
APPENDLXA
,­
,/
'

33
David
Thomassen,
Office
Health
and
Envi­
ronment
Research,
Office
of
Energy
Energy,
Washington,
DC
Beth
Viola,
Council
on
Environmental
Quality,
Executive
Office
of
the
President,
Washington,
DC
I
Research,
U.
S.
Department
of
Robert
Watson,
Environment
Division,
Office
of
Science
and
Technology
Policy,
Executive
Office
of
the
President,
Washington,
DC
Catherine
Woteki,
Science
Division,
Office
of
Science
and
Technology
Policy,
Executive
Office
of
the
President,
Washington,
DC
INSTITUTE
OF
MEDICINEBIATIONAL
ACADEMY
OF
SCIENCES
STEERING
CO"
3[
TTEE
David
P.
Rall
(Chair),
IOM
foreign
secretary;
ad
director
(Retired),
National
Institute
of
Eric
'Bq­
on,
Earth
System
Science
Center,
Pennsylvania
State
University,
University
Park,
PA;
Environmental
Health
Sciences,
Washington,
DC
Board
on
Atmospheric
Sciences
and
Climate
Boston;
Board
on
Health
Sciences
Policy
.

Medicine,
Mount
Sinai
School
of
Medicine,
New
York
City;
Board
on
Sustainable
Development
Research
Board
.
Deborah
Cotton,
assistant
professor,
Infectious
Disease
Unit,
Massachusetts
General
Hospital,

Philip
J.
Landrigan,
Ethe1.
H.
Wise,
professor
and
chairman,
Department
of
Community
.
­

Diane
M.
McKnight,
US.
Geological
Sury~
y,
Water
Resources
Division,
Boulder,
CO;
Polar
INSTITUTE
OF
MEDICINENATIONAL
ACADEMY
OF
SCIENCES
STEERING
COMr$
ITTEE
..

Bill
Colglazier,
executive
officer,
National
.
Loren
Setlow,
director,
Polar
Research
Academy
of
Sciences,
'National
Re­
Board,
National
Academy
of
search
Council
'
.
­
Sciences
Linda
DePugh,
administrative
assistant,
,
Valerie
Setlow,
director,
Division
ofHealth'
Division
of
Health
Sciences
Policy,
Sciences
Policy,
Institute
of
Institute
of
Medicine
­,
Medicine
Division
of
Health
Sciences
Policy
Medicine
Human
Health
and
Global
Climate
Change,
Kenneth
Shine,
president,
Institute
of
Karen
Hein,
executive
officer,
Institute
of
William
Sprigg,
'director,
Board
on
Atmo­

John
Perry,
staff
director,
Board
on
Sus­
David
Westbrook,
manager,
Federal
Con­
I
..
Medicine
spheric
Sciences
and
Climate,
David
tainable
Development,
National
tracts,
National
Academy
of
Sci­
,nces
Academy
of
Science
..
National
Academy
of
Sciences
Rosina
Bierbaum,
senior­
policy
analyst
Brett
Orlando,
intern
_.

Jason
Randall,
intern
Robert
Watson,
associate
director
for
environment
I
Jack
Gibbons,
assistant
to
the
presidentforscience
and
technology
J
...

.$
.
.­.
a
.

APPENDIX
B
Conference
Agenda
Conference
on
Human
Health
and
Global
Climate
Change
The
National
Science
and
Technology
Council,
the
Institute
of
Medicine,
and
the
National
Academy
of
Sciences
September
11­
12,
1995
National
hademy
of
Sciences
Main
Auditorium
2
1
0
1
Constitution
Avenue,
N.
W.
Washington,
DC
2041
8
AGENDA
MONDAY.
SEPTEMBER
11.1995
7:
30­
9:
00
aim.
.
REGISTRATION
.
'
9:
OO­
9:
lO
a.
m.
WELCOMING
REMARKS
.

Kenneth
I.
Shine,
M.
D.
..

President,
Institute
of
Medicine
John
H.
Gibb0ns;
Ph.
D.
Assistant
to
the
President
for
Science
and
Technology
'
..
..

9:
10­
9:
50
a.
m.
PANEL
I:
OVERVIEW
.
.

Kenneth.
1.
Shine,
M.
D.
(Chair)
President,
Institute
of
Medicine
n
e
Science
and
Impacts
of
Climate
Change
and
Ozone
Depletion
Associate
Director
for
the
Environment,
Office
of
Science
and
Technology
Policy,
Executive
Office
of
the
President
,
'
Robert
Watson,
Ph.
D:
.
.

Climate
Change
and
Human
Health
Risks
­
Anthony
McMichael,
Ph.
D.
Professor
of
Epidemiology,
London
School
of
Hygiene
and
Tropicai
Mehcine
950­
10:
lO
a.
m
QUESTION
AND
ANSWER
SESSION
..
:
J
U
L
WNFERENCE
ON
iiVMN
HEALTH
ANI)
GLdBAL
CLh4.
i
TE
CHANGE
i
"

10:
10­
11:
10a.
m.
PAP.
11:
CLIMATE
CHANGE
AND
INFEC?
.JS
DISEASES
Mar,
A.
Wilson,
M.
D.
(Pond
(3ilair)
Assistant
Professor,
Hiward
University
Vector­
Borne
Diseases
­
Duane
Gubler,
Sc.
D.

'
Centers
for
Disease
Control
and
Prevention
Emerging
and
Reemerging
Di.
wuycs
Steven
Morse,
Ph.
D.
Assistant
Professor
Of
Virology,
Rockefeller
University
11:
10­
12:
OO
p.
m.
QUESTION
AND
ANSWER
SESSION
12:
00­
12:
30
p.
m.
LUNCH
(Provided
in
the
@rent
Hall)

12:
30­
1:
OO
p.
m.
SPECIAL
BRIEFING
El
Niiio:
Analogue
for
Long­
Tt`
m
Climate
Change
J.
Michael
Hall,
Ph.
D.
Director,
Office
0fGloba.
I
Progrinls,
National
Oceanic
and
Atmospheric
Administratzn
Paul
Epstein,
M.
D.,
M.
P.
H.
Harvaxd
Medical
School
,

1:
OO­
1:
30
p.
m.
PANEL
111:
DIRECT
HEALTH
EFFECTS
FROM
CLIMATE
CHANGE
AND
OZONE
DEPLETION
Terri
Damstra,
Ph.
D.
(Pmel
c'ltojr)
.
Deputy
Director,
National
Institute
of
Environmental
Health
Sciences
Climate
Change
and
Heat
Srr~.~.~
Larry
Kalkstein,
Ph.
D.
Professor
of
Geography,
Univ.
er;
ity
of
Delaware
1:
30­
2:
00
p.
m.
QUESTION
AND
ANSWER
SESSION
c
..
.
,I
APPENDXB
2:
OO­
2:
45
p.
m.
PANEL
IV:
INDIRECT
HEALTH
EFFECTS
OF
CLIMATE
CHANGE
.
,.
'
37
'

Andrew
Haines,
M.
D.
(Panel
Chair)

8
­
Professor
of
Primary
Care,
Universityof
London
MedicalSchool
Impacts
on
Nubitional
Health
David
Oot,
Ph.
D.
Director,
Office
of
Nutrition
and
Health,
United
States
Agency
for
International
Development
Impacts
on
Fresh
Water
Quality
and
Quantity
Reds
Wolman,
Ph.
D.,
M.
A.
Professor
of
Geography,
Johns
Hopkins
University
2:
45­
3:
15
p.
m.

3:
15­
3:
30
p.
m.

3:
30­
4:
00
p.
m.
I
4:
00­
4:
30
p.
m.

4:
30­
5:
15
p.
m.

.­
Impacts
on
Air
Quality
Joel
Schwartz,
Ph.
D.
Professor
of
Environmental
pdemiology,
Harvaxd
University
QUESTION
AND
ANSWER
SESSION
COFFEE
BREAK
­
.

SPECIAL
ADDRESS
Implications
for
International
Cooperation
Mr.
J.
Brian
Atwood
Administrator,
United
States
Agency
for
International
Development
INTRODUCTION
OF
KEYNOTE
SPEAKER­
John
H.
Gibbons,
Ph.
D.
Assistant
to
the
President
for
Science
and
Technology
KEYNOTE
ADDRESS
The
Interplay
of
Climate
Change,
Ozone
Depletion,
and
Human
Health
,

Albert
Gore,
Jr.,
Vice
President
of
the
United
States
PANEL
V:
POLICY
IMPLICATIONS
­Anne
Solomon,
M.
P.
A.
(Panel
Chair)
.
.

Deputy
Assistant
Secretary
for
Science,
Technology
and
Health,
Cepartment
of
State
Implicationsfor
Global
Health
Suheillance
and
Response
Stephen
Joseph;
M.
D.,
M.
P.
H.
'
Assistant
Secretary
for
Health
Affairs,
Department
of
Defense
Implications
fo;
Disease
Prevention
Sir
George
A.
O.
Alleyne,
M.
D.
Director,
Pa0
American
Health
Organization
1
­

..

._
.
Inrylications
for
Education
in
the
Medical
and
Public
Health
Communities
Eric
Chivian,
M.
D.
Chair,.
Physicians
for
S.
ocial
Responsibility
a
5:
15­
5:
45
p.
15
QUESTION
AND
ANSWER
SESSION
5:
45­
6:
00
p.
m.
WRAP
U
p
,
INSTRUCTIONS
FOR
THE
NEXT
DAY
600
p.
m.
ADJOURN
..

6
1
.5
p.
m.
RECEPTION­
GREAT
HALL
TUESDAY,
SEPTEMBER
12.1995
7:
OO­
8:
OO
a.
m.
CONTINENTAL
BREAKFAST­
NAS
GREAT
HALL
8:
0019:
00
a.
m.
BREAKOUT
SESSION&
OCHAIRS
CONVENE
TO
DISCUSS
GOALS
AND
STRATEGIES
9:
OO­
9:
15
a.
m.
MORNING
PLENARY
Charge
to
Breakout
Groups
Bernard
Goldstein,
M.
D.
(Chair)

9:
15­
1230
p.
m.
BREAKOUT
GROUP
SESSIONS
*,

GROUP
1:
IMPLICATIONS
FOR
GLOBAL
HEALTH
SURVXILLANCE
AND
RESqONSE
.Ruth
Berkleman,
M.
D.
(Government
Cochair)
Deputy
Director,
National
Center
for
Infectious
Diseases,
Centers
for
Disease
Control
and
Prevention
Demise
Habte,
M.
D.
(Nongovernment
Cochair)
`Director,
Centre
for
Health
and
Population
Research
GROUP
2:
IMPLICATIONS
FOR
DISEASE
PREVENTION
,.
Sheila
Newton,
Ph.
D.
(Government
Cochair)
Coordinator
for
Environment,
Disease
Prevention
and
Health
Promotion,
Department
of
Hedth
agd
Human
Services
.
J.

..

'
Jonathan
Patz,
M.
D.,
M.
P.
H.
(Nungovernment
Cochair)
_­
Johns
Hopkins
University
..
APPENDLXB
GROUP
3:
IMPLICATIONS
FOR
EDUCATION
OF
THE
MEDICAL
AND
PUBLIC
HEALTH
COMMLMlTIES
­
Max
Lum,
Ed.
D.,
M.
P.
A.
(Government
C
h
a
i
r
)
Director,
Office
of
Health
Communications,
National
Institute
of
Occupational
Safety
and
Health
Bernard
Goldstein,
M.
D.
(NongovernmentCochair)
'

Chair,
Department
of
Environmental
and
Community
Medicine,
Robert
Wood
Johnson
School
of
Medicine
GROUP
4:
IhlPLTCATIONS
FOR
INTERNATIONAL
COOPERATION
Rafe
Pomerance
(Government
Cochair)
Deputy
Assistant
Secretary
fo
the
Environment
ind
Development,
State
Department
d
Rudi
Slooff,
Ph.
D.
(Nongovernment
Cochair)
.Division
of
Environmental
Health,
World
Health
Organization
39
GROT"
5
:
IMPLICATIONS
FOR
RESEARCH
AM)
DEVELOPMENT
NEEDS
Robert
Corell,
Ph.
D.
(Govehment
Cochair)
Chair,
Subcommittee
on
Global
Change
Research
and
Development,
United
States
Global
Change
Research
Program
'

David
P.
Rall,­
M.
D.,
Ph.
D.
(Nongovernment
Cochair)
Foreign
Secretary,
Institute
of
Medicine
GROUP
6:
IMPLICATiONS
FOR
PUBLIC
OUTREACH
AND
RISK
­

..

COMMUNICATION
Bill
Farland,
Ph.
D.
'(
GovernmehtCochair)
.
..
Director
of
National
Center
for
Environmental
Assessment,
Environmental
Protection
Agency
Thomas
Malone,
Ph.
D.
(
NingovernmentCochair)
.

Director
of
Sigma
Xi
Center's
Human
Development
Program
12:
30­
1:
OO
p.
m.
LUNCH
(PROVIDED
IN
THE
GREAT
HALL)

1:
OO­
1:
30
p.
m.
SPECLAL
ADDRESS
Biodiversity,
Climate
Change,
and
Human
Health
Thomas
Lovejoy,
'Ph.
D.
Counselorto
the
S
~C
T
C
W
~
for
Biodiversity
and
Environmental
hiairs,
Smithsonian
Institution
..
/
,I!

40
­x,
CONFERENCE
ONHUM
HEALTH%
GLOBAL
CLIAZATE
CHANGE
1:
30­
3:
30
p.
m.
'
CLOSING
PLENARY
_.

Bernard
Goldstein,
M.
D.
(Plenary
Chair)

Robert
Wood
Johnson
School
of
Medicine
Breakout
group
Cochairs
report
on
strategies
for
addressing
potential
health
effects
of
global
climate
change
developed
during
their
discussions.
­
Chair,
Department
of
Environ.&
ental
and
Community
Medicine,

3:
00­
4:
00
p.
m.
OPEN
DISCUSSION
4:
OO
p.
m.
ADJOURN
.,
,.
.­
..
.­
..
..

..
..
­,
....
'
..

­
.­
.
......
....
..
I
....
......
..........
..
­
..
,
..
..
­.
..
..
,/

.
/
*­.
/

APPENDIX
C
I
­

Speakers,
Authors,
Chairs,
and
Conference
Registrants
SPEAKERS
George
A.
O.
Alleyne
Bernard
Goldstein
Director
Pan
American
Health
Organization
4
Director
J.
Brian
Atwood
Administrator
,

United
States
Agency
for
International
Development
Eric
Chivian
Physicians
for
Social
Responsibility
.;

Rita
Colwell
President
American
Association
for
the
Advancement
of
Science
Teni
Damstra
Acting
Deputy
Director
International
Programs
'

National
Institute
of
Emironmental
Health
Sciences.

Paul
Epstein.
Harvard
Medical
School
.

,­
,
John
H.
Gibbons
Assistmt
to
the
President
for
Science'
and
Technology
..

­
Environmental
&d
Occupational
Health
Sciences
Institute
UMDNJ­
Robert
Wood
Johnson
Medical
School
Albert
Gore,
Jr;
­
Vice
President
.

United
States
of
America
Duane
Gubler
.Director
Division
of
Vector
Borne
Infectious
Diseases
Ceniers
for
Disease
Control
and
Prevention,

Demisse
Habte
Director
Centre
for
Health
and
Population
Research
.,
Andrew
Haines
:
Professor
of
Primary
Care
University
of
London
Medical
School
,

J.
Michael
Hall
Director
Office
of
Globs1
.Progms
National
Oceanic
&d
Atmospheric
Administration
41
..

,.
'
.
­
.
..
..
/

`

..

..
,.
.
.
.
.~,
.
Stephen
Joseph
Assistant
Secretary
for
Health
Affairs
U.
S.
Department
of
Defense
Larry
Kalistein
Department
of
Geography
University
of
Delaware
Margaret
Kripke
Department
of
Immunology
Anderson
Cancer
Center
Thomas
E.
Lovejoy
Secretary
for
Biodiversity
and
Environmental
Affairs
Smithsonian
Institution
Max
Lum
Associate
Director
for
Health
Communications
.

National
Institute
for
Occupational
Safety
and
Health
9
Anthony
McMichael
Department
of
Epidemiology
­and
­
Population
Science
London
School
of
Hygiene
and
Tropical
Medicine
Steven
Morse
Associate
Professor
`Rockefeller
University
David
Oot
Director
Office
of
Nutrition
and
Health
United
States
Agency
for
International
Development
I
.
Ari
Patrinos
Associate
Director
Office
of
Health
and
Environmental
Research
U.
S.
Department
of
Energy
David
Rall
Foreign
Secretary
Institute
of
Medicine
Joel
Schwartz
Associate
Professor
Environmental
Epidemiology
Program
Harvard
University
School
of
Public
Health
Kenneth
I.
Shine
President
Institute
of
Medicine
Rudi
Slooff
Division
of
Environmental
Health
­
World
Health
Organization
Anne
Soloman
Deputy
Assistant
Secretary
of
Science
Technology
and
Health
US.
Department
of
State
Robert
Watson
Associate
Director
for
the
Environment
Office
of
Science
and
Technology
Policy
Executive
Office
of
the
President
Mary
E.
Wilson
Assistant
Professor
Himaid
University
P
p
M.
Gordon
"Reds"
Wolman
Professor
of
Geography
Johns
Hopkins
University
"
.
,/
I
"­..
,/
APPENDX
C
­,
43
John
M.
Balbus­
Kornfeld
'
Assistant
Professor
of
Medicine
George'
Washington
University
Ann
Bostrom
School
of
Public
Policy
I
Georgia
Institute
of
Technology
Eric
Chivian
Assistant
Clinical
Professor
Department
of
Psychiatry
Harvard
Medical
School
Paul
R.
Epstein
Professor
The
Cambridge
Hospital
Harvard
University
Medical
School
Duane
Gubler
Director
Division
of
Vector
Bourne
Infectious
Diseases
Center
for
Disease
Control
and
Prevention'
19
r
..
AUTHORS
James
A.
Harrcli
Deputy
Director
Office
of
Disease
Prevention
and
Health
Promotion'
Public
Health
Service
.I
Hiram
Larew
Policy
Specialist
Agency
for
International
Development
Jonathan
A.
Patz
Research
Associate
Johns
Hopkins
School
of
Public
Health
Warren
T.
Piver
Adjunct
Professor
National
Institute
of
Environmental
Health
Sciences
Marla
Salmon
Director
Division
of
Nursing
Department
of
Health
and
Human
Services
Rudi
Slooff
..

Division
of
Environmental
Health
World
Health
Organization
'
­

Tim
Tinker
.
..

Health
Education
Specialist
Agency
for
Toxic
Substances
and
Disease
Registry
I
.

Continued
CHAIRS
Ruth
L.
Berkleman
Deputy
Dkector
National
Center
for
Infectious'Disease
Centers
for
Disease
Control
and
Prevention
I
Robert
W.
Core11
Subcommittee
on
Global
Change
Research
and
Development
U.
S.
Global
Change
Research
Program
Terri
Damstra
Acting
Deputy
Director
International
Programs
3
National
Institute
of
Environmental
Health
Sciences
William
H:
Farland
Director
National
Center
for
Environmental
Assessment
Environmental
Protection
Agency
'

..

Bernard
D.
Goldstein
Director
Environmental
and
Occupational
Health
Sciences
Institute
.

Robert
Wood
Johnson
Medical
School
.­
Demisse
Habte
Director
Center'for
Health
Population
Research
Andrew
Haines
Professor
of
Primary
Health
Care
University
College
of
Middiesex
Max
Lum
Director
,
.

Office
of
Health
Colmuications
National
Institute
of
Oc'cupational
Safety
and
Health
Thomas
F.
Malone.
,

..
Founding
Director
The
Sigma
Xi
Scientific
Research
Society
Sheila
A.
Newton
Coordinator
for
the
Environment
Office
of
Disease
Prevention
and
Health
Promotion,
Public
Health
Service
Jn
.
­
+7
:alth
Lb
"­.
/'

Foreign
­.
.
­0
.q
,
.
'\

Institute
of
Medicine
­

Kenneth
I.
Shine
President
,'

Institute'of
Medicine
Anne
K.
Solomon
j
'
'

Deputy
Assistant
Secretary
for
Science,
Technology
and
Health
U.
S.
.Department
of
State
Rudi
Slooff
.
.
~.

Division
of
Environmental
Health
World
HealthOrganization
.

Mary
E.
Wilson
Assistant
Professor
Harvard
University
.
Y
p
Colin
L.
Bradford,
Jr.
Agency
for
International
Deveiopment
­
Lynn
Bradley
'
­
I
Association
of
State
and
Territorial
Health
Officers
David
Brandling­
Bennet
Pan
American
Health
Organization
Bryna
Brennan
Pan
American
Health
Organization
Mary
J.
Brooks
Greencool
.

Allen
Buckingham
American
Association
of
Retired
Persons
..
Jim
Buizer
National
Oceanic
and
Atmospheric
Administration
Joy
E.
Carlson
Children's
Environmental
Health
Network
Gregory
R.
Carmichael
Center
for
Global
and^
RegionalEnvironmegt
'

Fran
Cm'
Agency
for
International
'
Development
t
I
.
..

1'

MichaelD.
Carr
,
.
,

U.
S.
Department
of
Interior
..

..

I
.

:
.
,­
..

..
..

...
..
.,

,.
..
­
.
_..~
..
....
...
..
­
.­
.
,
,
.
.­:
i
1
'_
­
,
...
........
.....
.......
"
.
.
..
....
..
..
.
.~
..
...
...................
..
...
..
Wiiline
can
Grantmakers
in
Health
Dennis
Can011
Agency
for
International
Development
James
C.
Cecil
The
Pentagon
D.
W.
Chen
'

Health
Resources
and
Services
Administration
Shoulquan
Cheng
University
of
Delaware
Mary
Ann
Childs
Universal
Healthwatch,
Inc.

Eunyong
Chung
U.
S.
Agency
for
International
Development
Christopher
Chyba
Princeton
University
Eric
Chivian
Harvard
University
Medical
School
David
L.
Clark
University
of
Wisconsin,
Madison
"
.

Emery
T.
Cleaves
Geological
Society
of
America
Daniel
G.
Colley
Cezters
foT
Disease
Control
and
Prevention
Rita
R.
Colwell
University
of
Maryland
Nugent
Conn
,Liberty
Tree
Alliance
Elizabeth
Cook
World
Resources
Institute
Leslie
B.
Cordes
Agency
for
International
Development
Anthony
Cortese
Consortium
for
Environmental
Education
in
Medicine
Robert
W.
Core11
U.
S.
Global
ChangeResearch
Program
Lisa
Cruz­
Avalos
.
.

Nurse
Consultant
Owen
Cylke
Tata
Energy
and
Resources
Institute
John
Daly
Agency
for
International
Development
Tem
Damstra
National
Institute
of
Environmental
He4lth
Sciences
i
David
Danzig
Sierra
Club
..

.........
Lora
E.
Fleming
University
of
Miami
Dana
A.
Focks
US.
Department
of
Agriculture
Loren
B.
Ford
Environmental
Protection
Agency
Michael
Fosberg
U.
S.
Department
of
Agriculture,
Forest
Service
Marvin
Frazier
U.
S.
Department
of
Energy
Kenneth
Frederick
Resources
for
the
Future
Clifford'
J.
Gabriel
American
Institute
of
Biological
Sciences
Ashok
Gadgil
Lawrence
Berkeley
National
Laboratory
Steven
K.
Galson,
Environmental
Protection
..

..

.
Agency
.

Mary
M.
Gant
National
Institute
of
Environmental
Health
'
Sciences
t
i
David
Gardiner
Environmental
Protection
Agency
Bronsoh
Gardner
Global
Climate
Coalition
.,
"

..

­
I
.

..
f
I
:
.­

~

._
..
.
,.
:
,
..
,.
­.
.

1
.
..
Martha
Geores
University
of
Maryland
Brigitta
Genven
.Netherlands
National
Institute
of
Public
Health
.
.

Herman.
Gibb
Environmental
Protection
Agency
John
H.
Gibbons
The
White
House
Len$%
E.
Gilbert
Columbia
University.

William
H.
Glaze
University
of
North
Carolina
Patricia
Glick
Sierra
Club
L*
nR.
Goldman
.
.

Environmental
Protection
Agency
Bemkd
D.
Goldstein
University
of
Medicine
and
Dentistry
of
New
Jersey
and
Robert
Wood.
Johnson
Medical
School
Robert
Gordon
Institute
of
International
Education
'.

Anne
Grambsch
Environmental
Protection
Agency
Erick'Gray
Universal
Healthwatcg;
Inc.
..

,.

..

.
..

..
..
..
.
­.
..
Robert
H.
Gray
University
of
Michigan
Gina
C.
Green
The
Nature
Conservancy
Harry
L.
Greene
I1
Massachusetts
Medical
Society
Nancy
Greenspan
Environmental
Network
Priscilla
C.
Grew
University
of
Nebraska,
Lincoln
Francesca
T.
Grifo
'Center
for
Biodiversity
and
.Consewation
­Museum
of
Natural
History
John
T.
Grupenhoff
National
Association
of
Physicians
for
the
Environment
Duane
J.
Gubler
Centers
for
Disease
.Control
and
Prevention
Audrey
Haaf
Coaland
Synfuels
'
:
Technology
Craig
Haas
Environmental
Protection
Agency
Demisse
Habte
Center
for
Health
and
Population
Research
j%.
5'
..

..
..
..

,
,.
..­
50
CONFERENCE
ON
HU'NHEA
HAND
GLOBAL
CLIMATE
CmNGE
Richard
J.
Jackson
Centers
for
Disease
Control
and
Prewntion
.
.,

Paul
F.
Jamason
University
of
Delaware
Christer
T.
Jansen
University
of
Turku,
Finland
Nyka
Jasper
US.
Agency
for
International
Development
Jim
Jensen
U.
S.
Agency
for
International
I
Development
.e
..

James
Jessleman
..

Academy
for
Educational
Development
Stephen
C.
Joseph
U.
S.
Department
of
Defense
John
R.
Justus
Library
of
Congress
Peter
R.
Jutro
Environmental
Protection
Agency
­­

Laurence
S.
Kalkstein
University
of
Delaware
'~
:.
Carla
Kappell
Development
John
'Kallos
.
­
1
Agency
for
International
..

.­
Columbia
Business
School
I
Timothy
P.
Kanaley
Institute
of
Medicine
.,
.
..
.

.
..
..
..

..
Tim
R.
Kramer
U.
S.
Department
of
Agriculture
.

Kalee
Kreider
Ozone
Action
Sally
Kane
Council
of
Economic
Advisers
Thomas
R.
Karl
National
Climatic
Data
Center
Eileen
Kennedy
Center
for'Nutrition
Policy
and
Promotion
Charles
Kennel
National
Aeronautic
and
S
p
v
Administration
John
L.
Kermond
National
Oceanic
and
Atmospheric
Association
Katherine
Kirkland
Association
of
Occupational
and
Environmental
Clinics
fiornas
M.
Kirlin
American
Petroleum
Institute
Heidi
M.
Klein
National
Association
of
City
and
County
Health
Officials
Edward
Knipling
US.
Department
of
Agriculture
..

Andrei
P.
Kozlov
National
Institutes
of
Health
Katharine
Kripke
Stanford
University
Margaret
Kripke
M.
D.
Anderson
Cancer
Center
Jon
Kusler
Association
of
Wetland
Manager'

Sandra
L:
LaFevre
Reinsurance
Association
of
America
'

Carol
Lancaster
Agency
for
International
Development
Stephen
Landry
­
.
,\

Agency
for
International
Development
Hiram
Larew
Agency
for
International
Development
Daniel
Lashof
Natural
Research
Defense
Cougcil
Sharon
LeDuc'
.
:
Environmental
Protection
Agency
;
Alexander
Leaf
Harvard
University
Medical
School
Joel
M
.
Leyy
National
Oceanic
and
Atmospheric
Administration
..
L
.
.
..
Harry
Moses
U.
S.
Department
of
Energy
*
Richard
Moss
Intergovernmental
Panel
on
Climate
Change
Jeryl
L.
Mumpower
Rockefeller
College
Robert
K.
Musil
.
Physicians
for
Social
Responsibility
Charles
E.
Myers
National
Science
Foundation
Carolyn
Needleman
Bryn
Mawr
College
Elvia
E.
Neibla
U.
S.
Department
of
Agriculture,
Forest
Service
Henry
Newhouse
Atmospheric
Administration
.
National
Oceanic
and
Sheila
A.
Newton
'.

U.
S.
Departinent
of
Health
and
Human
Services
CIaudia
Nierenberg
National
Oceanic
and
Atmospheric
Administration
Frances
P.
Noonan
George
Washington
r
University
School
of
Medicine
i
Michael
Northrop
Rockefeller
Brothers
Fund
Susan
Norwood
US.
Department
of
Energy
Edward
W.
Novak
Army
Environmental
Policy
Institute
Christine
O'Brien
Environmental
Protection
Agency
James
J.
O'Brien
Florida
State
University
Robeft
O'Keefe
Health
Effects
Institute
Tara
O'Toole
U.
S.
Department
of.
Energy
Ellen
Odgen
Agency
for
International
Development
David
Oot
Agency
for
International
Development
..
..

Michael
Oppenheimer
Environmental
Defense
Fund
Brett
Orlando
Office
of
Science
and
Technology
Policy
Joseph
V.
Osterman
Defense
Research
and
Acquisition
Horst
Otterstetter
Pm
Amcricm
Health
Organization
Countess
Alicia
Paoloui
National
Association
of
Physicians
for
the
Environment
John
Passacantmoo
Ozone
Action
Ari
Patrinos
U.
S.
Department
of
Energy
Jonathan
A.
Patz
Johns
Hopkins
School
of
Public
Health
David
Pelletier
Cornell
University
Michele
Pena
.
'
.
.
Climate
Institute
.
­

John
S.
Perry
National
Academy
of
Sciences
.
..

Jonathan
Pershing.
U.
S.
Dep­
ent
of
State
Anne
C.
Petersen
,

National
Science
Foundation
Karen.
Peterson
National
Institutes
of
Health
Annie
Petsonk
.
,

Environmkntal
De&
se,
Fund
Paul
B.
Phelps
Science
Writer
Winfred
M.
Phllips
University
of
Florida
..
.
54
CONFERENCE
UNH"
4NHE.
[HAND
GLO3AL
CLIWTE
CHANGE
Gabriel
Schmunis
­
Dave
Sharma
Anthony
Socci
Pa&
American
Health
U.
S.
Department
of
u­
s.
Global
Change
Research
OrganizatiodWorId
Health
Transportation
Program
Organization
Joe
Schwartz
Physicians
for
Social
Responsibility
Joel
Schwartz
Harvard
University
School
of
Public
Health
John
Kimball
Scott
National
Association
of
Physicians
for
the
Environment
Louise
Scott
Consultant
Glenn
E.
Schweitzer
.

National
­Research
Council
Jeff
Seabright.
Agency
for
International
Development
Stephen
Seidel
.

Council
on
Environmental
Quality
Loren
W.
Setlow
National
Research
Council
Valerie
P.
Setlow
Institute
of
Medicine
Moira
Shannon
I
U.
S.
Department
of
Health
a
d
Human
Services
,.

..
.

..
Eileen
L.
Shea
Rosemary
Sokas
Institute
of
Global
.George
Washington
Environmental
Society
University
Clive
Shiff
Jo$
s
Hopkins
University
Martha
Shimkin
Pan
American
Health
­
Organization,

Kenneth
I.
Shine
Institute
of
Medicine
John
.ShIaes
Global
Climate
Coalition
Robert
Shope
University
of
Texas
Michael
Simpson
Library
of
Congress
.

Holly
Sims
State
University
of
New
York
James
B.
Sitrick
.

Agency
for
International
Development
Rudi
Slooff
World
Health
Organization
Meta
Snyder
Registered
Nurse
­.

­.

"
.­
.
..
..

.
.
..
.­
William
Sprigg
National
Academy
of
Sciences
Ray
Squitieri
U.
S
.
Treasury
William
Sprigg
National
Academyof
Sciences
Jennifer
Steinbeig
..

Journal
of
NIH
Research
Macol
Stewart
'

National
Oceanic
and
Atmospheric
Ahinistration
Paul.
S
tolpman
Environmental
Protection
Agency
_.

Richard
E.
Stuckey
Center
for
Application
of
Sciences
and
Tec&
ol~
m
Nicholas
Sundt
Global
Change
Mark
Sutton
U.
S.
Global
Climate
Change
Research
Program
,.
"­.
c.

56
CONFERENCE
ONl%
JiM"&?­
.THAND
GLOBAL
CLIMATE
CMNGE
Natalie
Williams
Byron
L.
Wood
Timothy
Yarling
University
of
Delaware
National
Aeronautics
and
Japan
International
Mark
L.
Wilson
Ames
Research
Center
Yale
University
School
of
Teny
F.
Yosie
Medicine
Robert
C.
Worrest
EnvironmentalDevelopment
Mary
E.
Wilson
Information
Network
Space
Administration
a
*
Cooperation
i
1
Consortium
for
Earth
Science
Group
Harvard
University
cy
C.
Wilson
Climate
Institute
Tom
Wilson
Electric
Power
Research
Institute
Robert
Wolcott
Environmental
Protection
Agency
M.
'Gordon
Wolman
Johns
Hopkins
University
Stephen
W.
Wyatt
Centers
for
Disease
Control
and
Prevention
Tagny
R.
Wyles
Georgia­
Pacific
Corporation
Ann
G.
Wylie
University
of
Maryland
Roger
E.­
Wyse
University
of
Wisconsin­
Madison
Elizabeth
Younger
Younger
and
Rata
Eve
Carroll
Zentrick
Uniformed
Services
University
Brigitta
Zuiderna­
van
Gerwen
Netherlands
National
Institute
Environmental
ProEction
'
of
Public
Health
and
­
i
ERIC
CHNIAN,
M.
D.

Despite
increasing
evidence
that
climate
change
and
ozone
depletion
may
have
disastrous
consequences
for
human
health,
'
there
is
little
understanding,
either
among
policy­
makers
o
r
the
public,
of
the
extent
ofthe
possible
threat
to
human
life.
Physicians
and
public
health
professionals
should
be
central
figures
in
helping
to
promote
this
understanding,
but
they
are
by
.and
large
uniformed,
as
their
education
does
not
in
general
coverthe
relationship
of
global
environmental
change
to
human
health.
This
presentation
shall
look
at
the
role
of
the
medical
and
public
health
communities
in
global
environmental
issues,
such
as
climate
change
and
Ozone
depletion,
and
shall
address
the
grswing
need
for
their
education
and
involvement.

'
._
4
RITA
R.
COLWELL,
Ph.
D
The
origin
and
cyclical
nature
of
cholera
has
intrigued
scientists
and
public
health
officials.
Robert
Koch
postulated
environmental
origins'of
cholera,
but
proof
was
not­
established
until
the
tools
of
molecular
biology
and
immunology
were
available.
Work
on
environmental
aspects
of
cholera
during
the
past
20
years
has
revealed
an
association
of
Vibrio
cholerae
with
zooplankton
and
marine
and
estuarine
systems.
Furthermore,
the
capability
of
K
cholerae
to
­
.enter
a
dormant,
that
is,
viablerbut
noncultuiable
state,
has
offeredan
explanation
for
the
inability
to
isolate
it
between
epidemics.
With
.fluorescent
monoclonal
antibody
and
gene
probes,
coupled
with
PCR
implification,
it
has
been
possible
to
detect
and
monitor
K
cholerae
in
the
environment.
Furthermore,
it
has
been
shown
that
plankton
blooms
are
correlated
with
increased
incidence
of
I?
cholerae,
Studies
carried
out
in
Bangladesh
provided
the
link
between
cholera
outbreaks
and
plankton
populations.
Studies
in
progress,
employing
satellite
imagery,
will
permit
retrospective
and
prospective
analyses
of
marine
plankton
and
the
cholera
outbreak
in
Latin
America
during
1991­
1992.
The
El
Niiio
event.
appears
to
be
closely
associated
with
this
cholera
outbreak.
Perturbations
of
the
marine
ecosystem
may
be
the
key
to
the
eratic,
cyclical
nature
of
cholera
epidemics.

STEPHEN
C.
JOSEPH,
M.
D.,
M.
P.
H.
..
f"
Y
Global
surveillance
is
critical
to
national
security
and
plays
a
vital
role
in
the
mission
of
the
Department
.of
Defense
~DoD).
Military
forces
can
be
deployed
to
virtually
any
area
of
the
world
on
short
notice;
knowledge
of
emerging
diseases
and
their
potcntial
impact
on
military
operations
greatly
assist
us,
in
preparing
countsmeasures
to
avoid
such
threats,
reduce
their
­impact,.
and
provide
a
rapid
response
to.
outbreaks.
Ai
present,
three
things
need
to
be
I
:.

60
­.
CONFERENCE
ON&?.
JMNHEAI"
'Ab
GLOBAL
CLIUATE
CHANGE
ANTHONY
J.
MciMCHAEL,
L
k
A
.,
Ph.
D
Three
thmgs
about
this
topic
need
emphasis:
scale,
context,
and
&certainty.
First,
the
anticipated
health
risks
are­
not
of
a
localizedkind;
they
are
of
large
scale,
impinging
at
the
same"
(more
heatwaves,
air
pollution,
etc).
Rather,
they
would
arise
substantially
via
indirect
pathways
(by
disturbance
of
natural
systems,
e.
g.,
the
ecology
of
infective
agents,
food
production,
and
freshwater
supplies).
Third,
forecasting
them
entails
complexity,
.uncertainty,
a
populatioii
level,
and
tianscending
national
boundaries.
Second,
the
risks
are
not
just.
"more
of
1
1
and
a
long
time
horizon.
It
is
tempting
to
focus
on
the
more
familiar
risks;
increased
deaths
from
1
heatwaves
(especially
in
the
very
young,
frail,
and
elderly),
trauma
from
floods
and
storms,
and­­
from
stratospheric
ozone
depletion­
morecases
of
skincancer.
However,
in
the
long
term,
sustained
changes
in
climate
and
in
climate­
dependent
natural
systems
(particularly
if
also
subjected
to
other
environmental
or
ecological
stresses)
would
result
in:
(a)
altered
patterns
of
infectious
diseases,
especially
vector­
borne
diseases
(malaria,
dengue,
etc);
(b)
some
regional
declines
in
food
production;
and
(c)
population
displacement
(rising
seas,
declining
agriculture,
food
shortages,
and
weather
disaster9
and
its
many
public
health
consequences.
Combinations
of
mobile
infections,
malnutrition,
andsocial
stress­
especially
in
displaced
arid
migrating
groups"
cou1d
amplify
the
health
impacts
of
climate
ch'ange.
'
..

STEPHEN
S.
'MORSE,
Ph.
D
,I
­

.
"Emerging
infectious
diseases"
are
those
that
are
newly
appeared
in
the
population
or­
are
rapidly
increasing
their
incidence
or
geographic
range
(e.
g.,
HIVIAIDS,
cholera
in
South
­.
America
and
Africa,
Ebola
in
Africb,
and
Hantavirus
pulmonary
syndrome
and
Lyme
disease
in
the
United
States).
Most
emerging
infections
are
caused
by
pathogens
that
are
present
in
the
environment
but
are
newly
introduced
into
humans,
often
from
another
species
as
a
result
of
'
changing
ecological
or
environmental
conditions
that
increase
the
chance
of
human
contact,
or
'
are
infections
that
were
once
geographically
isolated
but
now
have
an
opportunity
to
reach
larger
human
populations.
Climate
may­
often
be
.a
factor.
For
example,
with
Hantavirus
pulmonary
syndrome
in
the
southwestern
United
States
in
1993,.
the
virus
probably
was
long
present
in
local
rodent
populations,
but
unusual
local
weather
conditions
..
led
to
an
exceptionally
large
rodent
'
population,
with
greater
opportunities
for
people
to
come
in
contact
with
infected
rodents
(and,
.
hence,
with
the
virus);
'the
weather
anomaly
itself
may
have
been
due
to
large­
scale
climatic
effects.
Human­
population.
movements,
whichcan
introduce
remote
infections
to
a
large.
population,
also
are
often
a
factor
in
the
emergence
of
disease.
The
mass,
movement
of
workers
from
rural
areas
to
cities,
largely
driven.
by
economic
conditions,
cm.
allow
a
previogsly
isolated
infection
to
reach
larger
numbers
of
people
(this
probably
happened
k
t
h
H
W
.
Climate
changes,
by
potentially
decrkasing
productivity
of
local
rural.
agriculture,
could
accelerate
this
migration.
As
a
final
exardple,
epidemiologists
have
long
documented
a
close
relationship
..

behveen
climatic
conditions
and
epidemics
of
childhood
bacterial
meningitis
(which
can
also
sprsad
loba
all^^
by
trave!)
in
parts
of
Africa
whzre
the
dmase
naFaily
occurs.
­*
,/
n.
'
I
,"­­

62
CONFERENCE
O
N
H
W
HEALTHAND
GLOBAL
CLIMATE
C
~N
G
E
changescould
have
adverse
effects
on
ecological
systems,
human
health,
andsocioeconomic
sectors.

.
AccGulation
of
CFCs
in
the
upper
atmosphere
has
already
led
to
world­
wide
depletion
of
the
ozone
layer
­and
an
ozone
hole
in
springtime
over
Antarctica.
Ozone
filters
out
harmful
ultraviolet
radiation
andkeeps
it
from'.
reaching
the
Earth's
surface.
Recentinternational
agreements
to
phase
out
CFCs
are
beginning
to
show
results;
we
now
expect
peak
depletion
to
occur
about
the
tum
of
the
century,
and
the
ozone
layer
should
recover
over
the
next
several
decades.
Ozone
depletion
and
climate
change
are
complex
problems
that
will
affect
the
economy
and
the
quality
of
life
for
this
and
future
generations.
The
lag
time
between
emission
of
the
gases
and
their
impact
is
on
the
order
of
decades
to
centuries;
SO,
too,
is
the
time
needed
to
reverse
any
effects.
Thus,
decisions
in
the
near
term
will
have
long­
term
consequences.

3
M.
GORDON
"REDS'
WOLMAN,
Ph.
D
The
geologic'
recordprovides
clear
evidence
ofclimaticallyinducedchangesinthe
quantity
and
quality
of
fresh
water
on
the
globe.
Major
fluctuations
in
climate,
in
the
last
10,000
yearsand
before,
have
resulted
in
the
creationanddemiseoflakesand
river,
systems.
Temperature
perturbations
of
only
a
few
degrees
have
also
been
accompanied
bysignificant
increases
in
the
frequency
of
floods,
and
similar
flood
events
are
associatedwith
El
Niiio
oscillations
in
some
regions.
Increasing
seasonal
runoff
at
some
locations
in
'the
United
States
may
be
associated
with
a
warning'trend
during
this
century,
but
the
record
is
not
consistent.
Climate
change
influences
.
water.
quality
directly
an'd
indirectly;
directly
.through
changes
in
water
temperature
and
associated
chemical
and
biochemical
phenomena
(e.
g.,
dissolved
oxygen,
algae),
and
indirectly
through
alterations
of
vegetationand
the'
erosionalprocessonland.
..
Sediment
yield
and
accompanying
organic'
and
inorganic
constituents
may
alter
the
quality
of
ambient
flow
aid
the
characteristics
of
the
habitat.
Human
impacts
acting
on
both
landscape
and
climate
are
often
inseparable
from
the
variable'behavior
of
natural
processes.

i
D
A
W
OOT,
Ph.
D.
..
..

I
Morethan
800
millionpeople,
.or
15
percent
oftheworld'stotalpopulation,
are
food
insecure.
.They
lack
the
economic
and
physical
access
to
adequate
food
to
meet
'their
dietary
needs
and
to
lead
healthy
and
productive
lives.
inadequate
food
consumption
is
a
vary
6.
cause
of
malnutrition
along
with
infection
and
poor
health.
For
1993,
the
UN
reports
that
over
34
hercent
of
all
preschool
children
i
n
developing
countries
are
malnourished.
From
recent
research
we
know
that
protein
energymalnutrition
(PEM),
even
in
its
mild­
to­
moderate
forms,
contributes
to
56
percent
of'child
deaths
in
53
developing
countrizs.
Tht
tsmbk
budes
ofPEh1
onchild
survival
is
evengreaterwhenthetollofhiddenhunger
due
tomicronutrient
i.
i
I
*

I
`/
,
P.

."

64
water
resourczs
management,
and
agriculture
(``
FamineEarly
Warning
Systems").
wi
additional
investigation,
the
potential
exists
to
extend
these
application
efforts
to
human
heal
("
Health
Early
Warning
Systems").
While
climate
circumscribes
the
distribution
of
m
a
disease
vectors,
extreme
events
may
determine
the
timing
of
outbreaks.

learned
from
El
Niiio's
effects
on
extreme
events:
changes
in
droughts,
floods,
and
minimur
and
maximum
temperatures.
Study
of
the
linkage
between
ENS0
and
health
is
beginning
t
reveal
important
threshold
effects
and
provide
tools
for
predicting
the
impacts
of
global
climat
change
that
can
be
tested
and
perfected
on
verifiable
timescales.
The
significance
of
ENSO
ma:
be
greater
still,
as
some
scientists
believe
that
global
climate
change
may
be
experienced
in
largr
part
through
changes
in
climatic
extremes
and
climate
variability.,
For
some
diseases,
changes
ir
climatic
extremes
may
be
even
more
important
than
changes
in
average
temperature
and
average
precipitation.
CONFERENCE
ON
H
U
M
ACTH
AND
GLOBAL
C
L
I
m
TE
CMN(

In
considering
El
Nifio
as
an
analogue
for
long­
tern
climate
change,
lessons
can
5
­,
,/
.P.
i
­"
.­

1
The
1997
U
S
Jimate
Action
Reporl,
Chapter
3,

,
submitted
.by
the
United
States
of
America
*
Under
the
United
NationsFramework
....

Convention
on
Climate
Change.

3
This
document
has
beenreformatted
to
facilitate
electronic
distribution.

Released
July,
1997
.........
~..

Plaintiff
Exhibit
No.
.3­
+
.
..
.
.
.

1997
U.
S
Climate
Action
Report.
Chapter
3
I
.
....
Table
of
Contents
Greenhouse
Gas
Inventory
(Title
Page)
...........................................................................
1
Greenhouse
Gas
Inventory
(Introduction)
.......................................................................
3
Recent
Trends
in
.U.
S.
Greenhouse
Gas
Emissions
........................................................
4
Carbon
Dioxide
Emissions
................................................................................................
7
The
Energy
Sector
...................................................................................................................................
7
Fossil
Fuel
Consumption
......................................................................................................................
7
Fuel
Production
and
Processing
....................
iii
.............................................................
:
.....................
9
Biomass
and
Biomass­
Based
Fuel
Consumption
...........
:
.....................................................................
9
Industrial
Processes
..........................................................................................................
­
.....................
9
Cement
Production
(10.5
MMTCE)
.......................................................................................................
9
Lime
Production
(3.7
MMTCE)
.............................................................................................................
9
Soda
Ash
Production
and
Consumption
................................................
:
...............................................
(1.6
MMTCE)
......................................................................................................................................
;;
9
Limestone
Consumption
(1.2
MMTCE)
.......................................................
.......................................
10
Carbon
Dioxide
Manufacture
(0.4
MMTCE)
........................................................................................
10
Changes
in
Forest
Management
and
Land
Use
....................................................................................
10
Methane
Emissions
.........
I
................................................................................................
10
Landfills
.........................................................
.........................................................................................
11
Agriculture
...............................................................................................................................................
11
Enteric
Fermentation
in
Domestic
Livestock
(34.9
MMTCE)
...............................................................
11
Manure
Management
(17.1
MMTCE)
...............
i
.................................................................................
12
Rice
Cultivation
(2.8
MMTCE)
...........................................................................................................
12
Field
Burning
of
Agricultural
Wastes
(0.04
MMTCE)
...........................................................................
12
Oil
and
Natural
Gas
Production
and
Processing
..................................................................................
12
Coal
Mining
..............................................................................................................................................
12
Other
Sources
.........................................................................................................................................
13
Nitrous
Oxide
Emissions
..................................................................................................
13
Agricultural
Soil
Management
and
Fertilizer
Use
................................................................................
13
Fossil
Fuel
Combustion
........................................................................................................................
13
Adipic
Acid
Production
.........................................................................................................
­
.................
13
Nitric
Acid
Production
...........................................................................................................................
14
Other
Sources
of
N20
............................................................................................................................
14
Emissions
from
HFCs,
PFCs
and
SF6
............................................................................
14
Emissions
of
Criteria
Pollutants
.....................................................................................
16
References
........................................................................................................................
17
2
..
U.
S.
Climate
Action
Report
..

.........
,i
,­.,
,
,'?

The
1997
U.
S.
ClimateActionReport,
Chapter
3,
submitted
by
the
United
States
of
America
Under
the
`United
Nations
Framework
Convention
on
Climate
Change.
I
Greenhouse
Gas
Inventory
4
Central
to
any
study
of
climate
change
is
the
development
of
an
emission
inven­
tory
that
identifies
and
quantifies
a
country's
primary
sources
and
sinks
of
green­
house
gases
(GHGs).
This
inventory
provides
both
(I)
a
basis
for
the
ongoing
development
of
a
comprehensive
and
detailed
methodology
for
estimating
sources
and
sinks
of
greenhouse
gases,
and
(2)
a
common,
consistent
mechanism
that
enables
all
signatory
countries
to
the
United
Nations'
Framework
Convention
on
Climate
Change
(FCCC)
to
e'stimate
emissions
and
to
compare
the
relative
contribution
of
different
emission
sources
and
greenhouse
gases
to
climate
change.
Moreover,
systematically
and
consistently
estimating
national
and
international
emissions
is
a
prerequisite
for
evaluating
the
cost­
effectiveness
and
feasibility
of
mitigation
strate­
gies
and
emission
reduction
technologies.

This
chapter
summarizes
the
latest
information
on
U.
S.
greenhouse
gas
emission
trends,
from
1990
to
1995
,
as
presented
in
the
draft
EPA
report,
Inventory
of
U.
S.
Greenhouse
Gas
Emissions
and
Sinks:
1990­
1995.
To­
ensure
that
the
U.
S.
emissions
inventory
is
comparable
to
those
of
other
FCCC
signatory
countries,
the
estimates
presented
here
were
calculated
using
baseline
methodologies
similar
to
those
recom­
mended
in
Volumes
1­
3
of
the
IPCC
Guidelines
for
National
Greenhouse
Gas
Inven­
tories
(IPCC/
OECD/
IEA/
UNEP
1995).
For
U.
S.
emission
sources
related
to
energy
consumption,
forest
sinks,
and
some
CH2ources,
the
IPCC
default
methodologies
were
expanded,
resulting
in
a
more
comprehensive
procedure
for
estimating
U.
S.
emissions.
Details
on
how
these
estimates
were
developed
are
available
in
the
1995
Inventory
of
U.
S.
Greenhouse
Gas
Emissions
and
Sinks:
1990­
1994
(U.
S.
EPA
1995)
and
i
n
the
L!
pcomir?
g
editicn.

This
document
has
been
reformated
to
facilitate
electronic
distribution.

Greenhouse
Gas
Inventory
­­
3
...
Recent
Trends
in
US.
Greenhouse
Gas
Emissions
the
atmosphere,
the'
cent
atmospheric
buildup
is
largely
the
result
of
human
activities.
Since
1800,
atmospheric
concentrations
of
these
greenhouse
gases
have
increased
by
30,
145,
and
15
percent,

6
Greenhouse
gasesjnclude
water
vapor,
carbon
respectively
(Ipcc
1996).
This
buildup
has
altered
dioxide
(CO,),
methane
(Cy),
nitrous
oxide
(yo),
the
Of
the
earth's
atmosphere,
and
may
and
ozone
(OJ.
Chlorofluorocarbons
(CFCs),
a
affect
future
global
climate.

family
of
human­
made
compounds,
and
other
com­
Beginning
in
the
195O's,
the
use
of
CFCs
in­
pounds
such
as
hydrofluorocarbons
(HFCs)
and
creased
by
nearly
10
percent
L1
)`
ear,
u
n
t
i
l
the
mid­
perfluorinated
carbons
(PFCs)
are
also
greenhouse
1980's
when
international
concern
about
Ozone
gases.
depletion
led
to
the
signing
of
the
Montreal
Protocol.

Other
nongreenhouse,
radiatively
important
Since
then,
the
consumption
of
CFCs
has
rapidly
gases
­
such
as
carbon
monoxide
(CO),
oxides
of
declined
as
they
are
phased
Ollt.
In
contrast,
LlSe
O
f
nitrogen
(NOx),
and
nonmethane
volatile
organic
CFC
substitutes
is
expected
to
grow
significantly.
compounds
(NMVOCs)
­
contribute
indirectly
to
Figure
3­
1
and
Table
3­
1
summarize
the
current
the
greenhouse
effect.
These
are
commonly
referred
U.
S.
greenhouse
gas
emissions
inl'entory
for
1990­
to
as
"tropospheric
ozone
precursors"
because
they
4
95.
They
present
the
estimated
sources
and
sinks
in
influence
the
rate
at
which
ozone
and
other
gases
are
millions
of
metric
tons
Of
carbon
equivalent
.

created
and
destroyed
in
the
atmosphere.
For
conve­
(MMTCE),
which
accounts
for
the
gases'
global
nience,
all
gases
discussed
in
this
chapter
are
generi­
warming
potentials.
cally
referred
to
as
"greenhouse
gases"
(unless
The
growth
in
U.
S.
greenhouse
gas
emissions
has
otherwise
noted).
been
erratic
from
1990
to
1995.
Emissions
from
Although
CO,,
CH,,
and
N$)
occur
naturally
in
anthropogenic
Sources
in
dropped
in
1991,
increaEd
steadily
through
1994,
and
then
slowed
down
in
1995.
Over
the
five­
year
period,
greenhouse
gas
emissions
rose
by
5.9
percent,
representing
Figure
3­
I
Recent
Trends
in
U.
S.
Greenhouse
Gas
Emissions
an
average
annual
increase
of
just
Over
one
(1990­
1995)
1800
__.....__...._......._....._._............,­.....­.......
percent.
This
trend
is
largely
attributable
to
changes
in
total
energy
consumption
resulting
1990s
and
the
subsequent
recovery.
U.
S.
1600
­.
f
r
o
m
t
h
e
economic
slowdown
in
t
h
e
e
a
r
l
y
.I
a,
1400
C
­
.­
energy
consumption
increased
at
an
average
­
m
annual
rate
of
1.5
percent
over
the
same
period
1200
­.
'
(DOEEIA
1996a).
The
increase
in
emissions
C
from
1993
through
1995
\vas
also
influenced
*­
creased
demand
for
fossil
fwls
(DOEEIA
s!
­.
­*
changes
in
CO,
emissions
from
fossil
fuel
­
*.
the
five­
year
period.
In
most
cases,
emissions
8
.­

Lu
0
Ei
looo
­1
by
generally
low
energy
prices,
which
in­

0
u)
800
C
0
Among
the
inventory's
greenhouse
gases,
.­
L
600
s
consumption
had
the
greatest
impact
during
a
f
r
o
m
m
e
t
h
a
n
e
,
N,
O,
HFCs,
PFCs,
and
sulfur
200
..
hexaflouride
(SF,)
have
rcrnained
relatively
.O
400
C
­

constant
or
have
increased
slightly.
For
ex­
ample,
methane
emissions
increased
by
just
over
4
percent.
The
rise
in
HFC,
PFC,
and
SF,
El
HFCS,
PFCS,
&
SFS
since
1990,
overa{/
em/
ssions
of
Nitrous
Oxide
CO;,
have
incrsssed,
while
emissions
emissions,
although
a
small
portion
of
the
of
othergreenhouseandphotcchemically
total,
is
significant
because
of
their
extremely
[17
Methane
importanfgassShave
remainedrlek!
ile&
high
global
warming
potentials
and,
i
n
the
cases
of
PFCs
and
S
t
,
their
long
atmospheric
0
1990
1997
1992
1993
1994
1995
Carbon
Dioxide
constant
ofd&
h&

4
­­
US.
Climate
Action
Report
I
,
­.
.\
i
Recent
Trends
in
U.
S.
Greenhouse
Gas
Emissions
(1990­
1995)
("T
s
of
Carbon
Equivalent)

Gasand
Source
­
A
.
Emissions
­
Direct
and
Indirect
Effects
1990
1991
1992
1993
_.
_.
.
".
......
.
.
....
.
....
.

Carbon
Dioxide
(0
2
)
1,228
1,213
1,235
1,268
1,291
1,305
Fossil
Fuel
Combustion
1,336
1,320
1,340
1,370
1,391
1,403
Industrial
Processes
and
Other
17
16
17
18
19
19
ZM
(3S'
(336
(357
(388
(470
1,422
Forests
(sink)
'
(125)
(123)
(122)
(120)
(119)
(117)

Methane
(CH?)
170
172
173
171
176
177
Landfills
56
58
58
60
62
64
Agriculture
50
57
52
52
54
55
Coal
Mining
24
23
22
20
21
20
Oil
and
Natural
Gas
Systems
33
33
34
33
33
33
Other
6
7
,&
6
6
6
Nitrous
Oxide
(Nz0)
36
,
37
37
38
39
40
Agriculture
17
17
17
18
18
18
Fossil
Fuel
Consumption
11
11
12
12
12
12
Industrial
Processes
8
8
8
8
9
9
HFCs
PFCs
SF6
12
12
13
14
17
21
5
5
5
5
7
8
7
7
8
8
8
8
U.
S:
Emissions
1,583
1,570
1,592
1,624
1,657
1,676
Net
U.
S,
Emissions
!:
1,458
1,447
i
,470
1,504
1,538
1,559
*These
estimates
for
the
conterminous
US
for
1990­
91
and
1993­
95
are
interpolated
from
forest
inventories
in
1987
and
1992,
and
projections
through
2040.
The
methodology
reflects
long­
term
averages
rather
than
specific
events
in
any
given
year.
Note:
The
totals
presented
in
the
summary
tables
in
this
chapter
may
not
equal
the
sum
of
the
individual
source
categories
due
to
rounding.
Nitrous
oxide
emissions
rose
by
just
under
10
percent
during
the
period,
primarily
for
two
reasons.
First,
fertilizer
use,
which
account
for
approximately
46
percent
of
total
U.
S.
N,
O
emissions,
increased
sigificantly
during
1993­
95
as
farmers
planted
more
acreage
and
worked
to
replace
nutrients
lost
i
n
the
1993
floods.
And
second,
emis­
sions
from
other
categories
grew
slightly
as
the
U.
S.
economy
grew.
HFCs,
PFCs,
and
SF,
emis­
sions
are
increasing,
along
with
their
expanded
use
as
substitutes
for
CFCs
and
other
ozone­
depleting
compounds
being
phased
out
under
the
terms
of
the
Montreal
Protocol
and
Clean
Air
.
Act
Amendments
(IPCC/
OECD/
IEA/
UNEP
1995).
Two
major
contributors
to
the
rise
in
HFC
emissions
since
1990
are
the
use
of
HFC­
134a
for
mobile
air
conditioners
and
the
emission
of
HFC­
23
during
the
production
of
the
refrigerant
HCFC­
22.
The
following
sections
present
the
anthropogenic
sources
of
greenhouse
gas
emissions,
briefly
discuss
emis­
lifetimes.
Greenhouse
gas
emissions
were
partly
sion
pathways,
summarize
the
emission
estimates,
offset
by
carbon
sequestration
in
forests.
and
explain
the
relative
importance
of
emissions
the
primary
greenhouse
gases
to
total
U.
S.
emissions
in
1995,
with
CO,
emissions
accounted
for
the
largest
share.
The
largest
change
i
n
methane
emission
estimates
compared
to
earlier
inventories
is
in
the
natural
gas
sector,
where
emissions
have
been
Total
1995
US.
G
r
e
e
n
h
o
u
s
e
G
a
s
Emissions
adjusted
upward
by
more
than
75
percent
due
to
HFCs
improved
estimation
methods;
however,
these
revised
NitrousOxide
(1.2%)

emissions
have
not
changed
significantly
during
1990­
95.
LarSei
landfills,
apanded
animal
popuh­
tions,
and
more
widespread
use
of
liquid
manure
management
systems
increased
methane
emissions
from
waste
management
and
agricultural
activities.
In
contrast,
improved
methane
recovery
and
lower
coal
production
from
gassy
mines
have
reduced
methane
emissions
from
coal
mining.
(84.8%)
Figure
3­
2
illustrates
the
relative
contribution
of
from
each
Source
category.

Figure
3­
2
Methane
(2.4%)

(10.6w
\
PFCs
(O.
S%/
J
Carbon
Dioxide
Greenhouse
Gas
Inventory
­­
5
~
~~~~
Box
3­
I
The
Global
Warming
.
..
..
Potential
Concept..
.
..

I
­
,..
.
..
..

Gases
can
contribute
to
the
greenhouse
effect
both
directly
and
indirectly.
Direc
when
the
gas
itself
is
a
greenhouse
gas;
indirect
radiative
forcing
occurs
when
ch
transformations
of
the
original
gas
produce
a
greenhouse
gas,
or
when
a
gas
infl
atmospheric
lifetimes
of
other
gases.

The
concept
of
Global
Warming
Potential
(GWP)
has
been
developed
to
allow
scientists
and
policy
makers
to
compare
the
ability
of
each
greenhouse
gas
to
trap
heat
in
the
atmosphere
relative
to
another
gas.
C02
was
chosen
as
the
reference
gas
to
be
consistent
with
IPCC
guidelines
(IPCCIOECDIIENUNEP
1995).
a
All
gases
in
this
inventory
are
presented
in
units
ofmillion
metric
tonnes
of
carbon
equivalent,
or
MMTCE.
Carbon
comprises
12/
44
of
carbon
dioxide
by
weight.
The
following
equation
may
be
used
to
convert
MMTsof
emissions
of
greenhouse
gas
(GHG)
x
to
MMTCE:

"TCE=("
T
of
GHGx)(
GWP
of
GHGx)(
l2/
44)

The
GWP
of
a
greenhouse
gas
is
the
ratio
of.
global
warming,
or
radiative
forcing
(both
direct­
and
indirect),
from
one
kilogram
of
a
greenhouse
gas
to
one
kilogram
of
C02
over
a
period
of
time.
While
any
time
period
may
be
selected,
this
report
uses
the
1
OO­
year
GWPs
recommended
by
the
IPCC
and
employed
for
U.
S.
policy
making
and
reporting
purposes
(IPCC
1996).

The
GWPs
of
some
selected
GHGs
are
shown
here.
GWPs
are
not
provided
for
the
photochemically
important
gases
CO,
Nox,
NMVOCs,
and
SO2
because
there
is
no
agreed­
upon
method
to
estimate
their
contributions
to
climate
change,
and
they
affect
radiative
forcing
only
indirectly
(IPCC
1996).
Global
Warming
Potential
The
higher
global
waiming
potential
lower
emitting
,greenhouse
gases
significantly
increases
their
contribulio
the
greenhouse
effect.
For
example,
o
100­
year
time
horizon,
nitrous
oxid?
i
times
more
effective
than
carbon
dioxi
trapping
heat
in.
the
atmosphere.
.
.,

GWP
..
.
..
.
..
.
.
.,
.
_.
.
..

Gas
..

(1
00
Years)
Carbon
Dioxide
1
­

Methane
,
21
Nitrous
Oxide
31
0
HFC­
23
1
1,700
HFC­
125
2,800
HFC­
134a
1,300
HFC­
I
43a
3,800
HFC­
152a
140
HFC­
227ea
2,900
HFC­
43­
1
Omme
\
1,300
CF4
6,500
CZFS
9,200
c4F10
7,000
c6F14
7,400
PFCs/
PFPEs
7,400
SF6
23,900
6
­­
U.
S.
Climate
Action
Report
Carbon
Dioxide
Emissions
figure
3­
3
­
Sources
of
U.
S.
Energy
Consumed
in
1995
The
global
carbon
cycle
is
made
up
'of
large
carbon
flows
andre%
eIyoirs.
Hundreds
of
billions
of
tons
of
carbon
in
the
form
of
CQare
absorbed
by
the
oceans
or
trees
(sinks)
or
are
emitted
to
the
atmo­
sphere
annually
through
natural
processes
(sources).
When
in
equilibrium,
carbon
fluxes
among
the
various
reservoirs
are
roughly
balanced.

has
been
increasingly
compromised.
Atmospheric
concentrations
of
CO,
have
risen
about
30
percent,
Since
the
Industrial
Revolution,
this
equilibrium
(25%)
(38%)
Natural
Gas
Petroroieum
Source:
.!
L
S.
DOEAEIA
19955
principally
because
of
fossil
fuel
combustion,
which
accounts
for
99
percent
of
total
U.
S.
COgmissions
(Seki
1995).
Changes
in
land
use
and
forestry
activi­
ties
can
emit
CO,(
e.
g.,
through
conversion
of
fwst
land
to
agriculturh
or
urban
use)
and
can
act
as
a
sink
for
­
or
absorb
­
CO,
(e.,..,
through
improved
forest
management
activities).

CO,,
while
the
remainder
of
this
section
discusses
CO,
­
emission
trends
in
greater
detail.
Table
3­
2
summarizes
US.
sources
and
sinks
of
The
Energy
Sector
percent
of
annual
U.
S.
greenhouse
gas
emissions.
Of
that
share,
approximately
85
percent
is
produced
through
fossil
fuel
combustion,
and
the
remaining
15
percent
comes
from
renewable
or
other
energy
sources,
such
as
hydropower,
biomass,
and
nuclear
energy
(Figure
3­
3).
Energy
related
activities
other
than
fuel
combustion
also
emit
greenhouse
gases
Energy­
related
activities
accoyt
for
roughly
87
Fossil
Fuel
Consumption
ResidenIial
Commercial
Industrial
Transportation
U.
S.
Territories
Fuel
Production
and
Processing
6.2
1.7
Cement
Production
38.5
10.5
Lime
Production
13.6
3.7
Limestone
Consumption
4.4
,
'
1.2
Soda
Ash
Production
and
Consumption
5.9
1.6
Carbon
Dioxide
Manufacture
1.5
0.4
....
....
..
...
.....
I
,..
.
.
,.
.
....
..
...
...
..
..
..

.
...

Note:
The
totals
provided
here
do
not
reflect
emissions
from
bunker
fuels
used
in
international
transport
activities.
At
its
Ninth
Session,
the
Intergovernmental
Negotia:
ing
Comm;:!
ee
instruc:
ed
countries
to
report
these
emissions
separately,
and
not
include
them
in
national
totals.
U.
S.
emissions
from
bunker
fuels
were
zpproximately
22
MMTCE
in
1995.
(primarily
methane),
such
as
those
associated
with
producing,
transmit­
ting,
storing,
and
distributing
fossil
fuels.

Fossil
Fuel
Consumption
The
amount
of
carbon
in
fossil
fuels
vanes
significantly
by
fuel
type.
For
example,
coal
contains
the
highest
amount
of
carbon
per
unit
of
energy,
natural
gas
has
about
45
percent
less
than
coal,
and
petroleum
has
about
20
percent
less.
Carbon
dioxide
is
the
most
significant
GHG
emitted
in
the
U.
S.
Currently,
carbon
dioxide
makes
up
85
percent
of
the
total
US.
GHG
emissions
and
the
combustion
of
fossil
fuels
accounts
for
99
percent
of
that
portion.
In
1995,
U.
S.
fossil
fuel
combustion
eniited
1,403
million
metric
tons
of
carbon
equivalent
(MMTCE).
Tetal
consumption
of
fossil
fuels
during
1990­
95
increased
at
an
average
annual
rate
of
1.2
percent,
primarily
because
of
eco­
nomic
groivth
and
generally
low
energy
prices.

Greenhouse
Gas
Inventory
­­
7
...
x
,
/

*.
.I
.,
/

Overall,
emissions
from
foss
Jel
consumption
energy
consumed
i
n
sector
comes
from
petro­
have
increased
from
1990
to
1995.
While
emissions
leum­
based
products.
Nearly
two
thirds
of
the
of
CO,
in
1991
were
approximate1y
1.2
percent
lou.
er
emissions
result
fI'Om
gasoline
Consumption
in
than
the
1990
baseline
level,
in
1992
they
increased
automobiles
and
other
vehicles.
The
remaining
by
about
1.6
percent
abo.
ve
the
1991
levels,
thus
emissions
stem
from
meeting
other
transportation
returning
emissions
to
slightly
more
than
the
1990
demands,
including
the
combustion
of
diesel
fuel
for
baseline,
By
1993,
CO,
emissions
from
fossil
fuel
the
trucking
industry
and
jet
fuel
for
aircraft.
combustion
were
approximately
2.5
percent
greater
Residential
and
Commercial
Sectors.
The
than
i
n
1990;
in
1994,
they
were
about
4.1
percent
residential
and
commercial
Sectors
account
for
about
higher
than
1990;
and
in
1995,
they
were
about
5
19
and
16
percent,
respectively,
of
CQemissions
percent
higher.
This
trend
is
largely
attributable
to
frorll
fossil
fuel
consumption,
Both
s&
tors
rely
changes
in
total
energy
consumption
resulting
from
heavily
on
electricity
for
meeting
energy
needs,
with
the
economic
slowdown
in.
the
United
States
i
n
thc
about
two­
thirds
to
three­
quarters
of
their
emissions
early
1990s
and
the
subsequent
recovery.
attributable
to
electricity
consumption.
End
use
Despite
the
continued
increase
in
natural
gas
and
applications
include
lighting,
heating,
cooling,
and
coal
consumption
in
1995,
the
total
amount
of
operating
appliances.
The
remaining
emissions
are
petroleum
used
for
energy
production
declined
by
.$
largely
due
to
the
consumption
of
nafural
gas
and
oil,
about
0.2
percent,
as
somewhat
higher
prices
for
primarily
for
meeting
heating
and
cooking
needs.
cruds
oil
in
1995
led
electric
utilities
and
industry
to
Electric
Utilities.
The
United
States
relies
on
decrease
their
consumption
of
petroleum
by
32
and
electricity
to
meet
a
significant
portion
of
its
energy
1.9
percent,
respectively,
and
to
rely
more
heavily
on
requirements
­­
e.
g.,
lighting,
electric
motors,
and
natural
gas,
coal,
nuclear
electric
power,
and,
renew­
heating
and
air
conditioning.
As
the
largest
consum­
able
energy.
In
contrast,
consumption
of
petroleum
ers
of
U.
S.
energy
(averaging
28
percent),
electric­
increased
1.3
percent
in
the
residential
and
commer­
utilities
are
collectively
the
largest
producers
(ap­
cia1
sectors,
and
about
1.6
percent
in
the
trsnsporta­
proximately
3
j
percent)
of
U.
S.
CO,
emissions
tion
sector.

emissions
included
steam
production
for
industrial
processes,
gasoline
consump­
tion
for
transportation,
heating
in
residen­
tial
and
commercial
buildings,
and
generation
of
electricity.
Petroleum
products
across
all
sectors
of
the
economy
accounted
for
about
42
percent
of
total
U.
S.
energy­
related
C0,
emis­
sions;
coal,
36
percent;
and
natural
gas,
22
percent.
Industrial
Sector.
Industry
accounts
for
the
largest
percentage
of
U.
S.
emis­
sions
from
fossil
fuel
consumption
(Figure
3­
4).
About
two­
thirds
of
these
emissions
result
from
producing
steam
and
process
heat,
while
the
remaining
third
rzsults
from
providing
electricity
for
such
uses
as
motors,
electric
furnaces,
ovens,
and
lighting.
Transportation
Sector.
In
the
same
league
as
the
industrial
sector,
the
trans­
portation
sector
accounts
for
about
31
percent
of
U
S
.
CO,
emissions
from
fossil
fuel
consumption.
Virtually
all
of
the
The
energy
related
sources
of
CQ
.
(Figure
3­
5).

Ffgue
3­
4
and3­
5
1995
Sectoral
Emissions
of
C02
from
Fossil
Fuel
Combustion
Cwnmercial
15.7%
lnduitri+
7f
Mte:
In
this
piechart,
.5%)
electric
utit~
v
emisicns
8R
distfitutedto
each
enduseseabracccrdhg
to
each
setofs
share
d
dectricity
wnsunption.

Transp
crtation
i
Rsickntial
(7%)
Ccmrnerciaf
I
E
I
Coal
]

.A
(5%)

I
0
100
200
300
400
500
MilJon
Mdrc
Tons
Czxbon
Equivalent
8
­­
U.
S.
Climate
Action
Report
~~
~~~
'7
The
type
of
energy
eleci
utilities
consume
directly
affects
the
volume
of
CO,
emitted.
For
example,
some
of
this
electricity
is
generated
with
low­
emitting
technologies,
such
as
nuclear
energy,

4
hydropower,
or
geethermal
energy.
However,
electric
utilities
rely
on
coal
for
over
half
of
their
total
energy
requirements
and
account
for
about
87
percent
of
all
coal
consumed
i
n
the
United
States.
Consequently,
changes
i
n
electricity
demand
can
significantly
affect
coal
consumption
and
associated
CQ
emissions.

Fuel
Production
and
Processing
at
natural
gas
systems
and
oil
wells.
The
methane
trapped
in
natural
gas
systems
or
oil
wells
is
flared
to
relieve
the
rising
pressure
or
to
dispose
of
snlall
quantities
of
gas
that
are
not
commercially
mark
­
able.
As
a
result,
the
carbon
contained
in
the
met
1
ane
becomes
oxidized
and
forms
CO,.
In
1995,
flaring
activities
emitted
approximately
2
MMTCE,
or
about
0.1
percent
of
total
U
S
.
Cqemissions.
Emissions
trends
from
fuel
production­
and
processing
are
dictated
by
fossil
fuel
consumption.

Biomass
and
Biomass­
Based
Fuel
Consumption
Biomass
fuel
is
used
primarily
by
the
industrial
sector
in
the
form
of
fuel
wood
and
wood
waste,
while
the
transportation
sector
dominates
the'use
of
biomass­
based
fuel,
such
as
ethanol
from
corn
or
woody
crops.
Ethanol
and
ethanol
blends,
such
as
gasohol,
are
typically
used
to
fuel
public
transport
vehicles.
Carbon
dioxide
is
produced
via
flaring
activities
Although
these
fuels
do
emit
C9,
their
emis­
sions
do
not
increase
total
atmospheric
CQbecause
the
biomass
resources
are
consumed
on
a
sustainable
basis.
For
example,
fuel
wood
burned
one
year
but
regrown
the
next
only
recycles
carbon,
rather
than
creating
a
net
increase
in
total
atmospheric
carbon.
CO,
emissions
from
biomass
consumption
were
approximately
51
MMTCE,
with
the
industrial
sector
accounting
for
72
percent
of
the
emissions,
and
the
residential
sector,
25
percent.
CQ
emissions
from
ethanol
use
in
the
United
States
have
been
rising
in
recent
years
due
to
a
number
of
factors,
including
extension
of
federal
tax
exemptions
for
ethanol
production,
the
Clean
Air
Act
Amendments
mandat­
ing
the
reduction
of
mobile
source
emissions,
and
the
Energy
Policy
Act
of
1992,
which
established
incentives
for
increasins
the
use
of
alternative­
fueled
vehicles.
In
1995,
total
U.
S.
CQ
emissions
from
ethanol
were
2
MMTCE.
/
,
".

Inc
trial
Processes
Emissions
are
often
produced
as
a
by­
product
of
various
nonenergy­
related
activities.
For
example,
in
the
industrial
sector
raw
materials
are
often
chemi­
cally
transformed
from
one
state
to
another.
This
transformation
often
releases
such
greenhouse
gases
as
CO,.
The
production
processes
that
emit
CO,
include
cement
production,
lime
production,
lime­
stone
consumption
(e.
g.,
in
iron
and
steel
making),
soda
ash
production
and
use,
and
CQmanufacture.
Total
carbon
dioxide
emissions
from­
these
SOllrCeS
were
approximately
17.4
MhlTCE
in
1995,
account­
ing
for
about
1
percent
of
total
U.
S.
Cemissions.
In
1995,
emissions
from
these
sources
were
approxi­
mately
10.5,
3.7,
1.2,
1.6,
and
0.4
MMTCE,
respec­
tively,
for
a
total
of
17.4
MMTCE,
or
about
one
percent
of
total
U.
S.
Cofmissions.
Since
1990,
emissions
from
cement,
lime,
and
CQ
manufacturing
have
increased
slightly;
emissions
from
limestone
use
have
fluctuated;
while
emissions
from
soda
ash
production
remained
constant
from
1990­
1994
and
increased
in
1995.
*

Cement
Production
(
.
MMTC
)

production
of
clinker,
an
intermediate
product
from
which
finished
Portland
and
masonry
cement
are
made.
Specifically,
carbon
dioxide
is
created
when
calcium
carbonate
(CaCOJ
is
heated
in
a
cement
kiln
to
form
lime
and
CO,
This
lime
combines
with
other
materials
to
produce
clinker,
while
the
CQis
re­
leased
into
the
atmosphere.

Lime
Production
(
.
MMTC
)

and
paper
manufacturing,
and
water
and
sewage
treatment.
It
is
manufactured
by
heating
limestone
(mostly
calcium
carbonate
­
CaCO,)
in
a
kiln,
creating
calcium
oxide
(quicklime)
and
CQ
which
is
normally
emitted
to
the
atmosphere.

Soda
Ash
Production
and
Consumption
­

Carbon
dioxide
is
produced
primarily
during
the
Lime
is
used
in
steel
making,
construction,
pulp
(
.
MMTC
)
Commercial
soda
ash
(sodium
carbonate)
is
used
i
n
many
consumer
producis,
s
x
h
as
glass,
soap
and
detergents,
paper,
textiles,
and
food.
During
the
manufacturing
of
these
products,
natural
sources
of
sodium
carbonate
are
heated
and
transformed
into
a
crude
soda
ash,
in
which
CQis
generated
as
a
by­
product.
In
addition,
CO,
is­
released
when
the
soda
ash
is
consumed.

~~~
~

Greenhouse
Gas
Inventory
­­
9
"y
.,

limestone
Consumption
(
,
h
'C
)

variety
of
industries,
including
the
construction,
agriculture,
chemical,
and
metallurgical
industries.
Fdr
example,
limestone
can
be
used
as
a
purifier
in
refining
metals.
In
the
case
of
iron
ore,
limestone
heated
i
n
a
blast
furnace
reacts
with
impurities
i
n
the
iron
ore
and
fuels,
generating
COqs
a
by­
product.
Limestone
is
also
used
in
flue
gas
desulfurization
systems
to
remove
sulfur
dioxide
from
the
exhaust
gases.

Carbon
Dioxide
Manufacture
(
.
MMTC
)

economy,
including
food
processing,
beverage
manufacturing,
chemical
processing,
crude
oil
products,
and
a
host
of
industrial
and
miscellaneous4
applications.
For
the
most
part,
the
CQused
in
these
applications
will
eventually
be
released
into
the
atmosphere.
Limestone
is
a
basic
raw
material
used
by
a
wide
Carbon
dioxide
is
used
in
many
segments
of
the
Changes
in
Forest
Management
and
Land
Use
How
the
Earth's
land
resources
are
managed
can
alter
the
natural
balance
of
trace
gas
emissions.
,

Everyday
land­
use
decisions
include
clearing
an
area
of
forest
to
create
cropland
or
pasture,
restocking
a
logged
forest,
draining
a
wetland,
or
allowing
.a
pasture
to
revert
to
a
grassland
or
forest.

(737
million
acres)
of
U.
S.
land
in
the
contiguous
48
states
(USDANSFS
1990),
are
also
an
important
terrestrial
sink
for
Cq.
Because
approximately
half
the
dry
weight
of
wood
is
carbon,
as
trees
add
mass
to
trunks,
limbs,
and
roots,
carbon
is
stored
in
relatively
long­
lived
biomass
instead
of
being
released
to
the
atmosphere.
Soils
and
vegetative
cover
also
provide
potential
sinks
for
carbon
emis­
sions.
Forests,
which
cover
about
295
million
hectares
In
the
United
States,
improved
forest­
manage­
ment
practices
and
the
regeneration
of
previously
cleared
forest
areas
have
resulted
in
a
net
uptake
(sequestration)
of
carbon
in
U.
S.
forest
lands.
This
uptake
is
an
ongoing
result
of
land­
use
changes
in
previous
decades.
For
example,
because
of
improved
agricultural
productivity
and
the
widespread
use
of
tractors,
the
rate
of
clearing
forest
land
for
crop
cultivation
and
pasture
slowed
greatly
in
the
late
19th
century,
and
by
1920
this
practice
had
all
but
ceased.
As
farming
expanded
in
the
Midwest
and
West,
large
areas
of
previously
cultivated
land
in
the
East
were
n
brought
out
of
crop
.
duction,
primarily
between
1920
and
1950,
and
were
allowed
to
revert
to
forest
land
or
were
actively
reforested.
Since
the
early
1950s,
the
managed
growth
of
private
forest
land
in
the
East
has
nearly
doubled
the
biomass
density
there.
The
1970s
and
1980s
saw
a
resurgence
of
federally
sponsored
tree­
plantins
programs
(e.
g.,
the
Forestry
Incentive
Program)
and
soil
conservation
programs
(e.,..,
the
Conservation
Reserve
Program),
which
have
focused
on
reforesting
previously
harvested
lands,
improving
timber­
management,
combating
soil
erosion,
and
converting
marginal
cropland
to
forests.

1995
is
estimated
to
have
been
an
uptake
of
i17
MMTCE
(which
includes
the
carbon
stored
in
the
U.
S.
wood
product
pool
and
in
landfiils).
This
carbon
uptake
represents
an
offset
of
about
S
percent
of
the
199
5
CO,
emissions
from
fossil
fuel
combustion
during
this
period.
The
amount
of
carbon
sequestered
through
changes
in
U.
S.
forestry
and
land
use
prac­
tices
continues
to
decline,
as
the
expansion
of
eastern
forest
c
o
v
e
r
s
l
o
w
s
d
o
w
n
.
­
As
a
result
of
these
activities,
the
net
CO,
flux
in
Methane
Emissions
Atmospheric
methane
(CH,)
is
an
integral
component
of
the
greenhouse
effect,
second
only
to
CO,
as
an
anthropogenic
source.
Methane's
overall
contribution
to
global
warming
is
large
because
it
is
estimated
to
be
twenty­
one
times
more
effective
at
trapping
heat
in
the
atmosphere
than
CQover
a
100­
year
time
horizon
(IPCC
1996).
Over
the
last
two
centuries,
methane's
concentration
in
the
atmosphere
has
more
than
doubled.
Scientists
believe
these
atmospheric
increases
are
due
largely
to
increasing
emissions
from
anthropogenic
soarces,
such
as
landfills,
agricultural
activities,
fossil
fuel
combus­

FQure
3­
6
U.
S.
Sources
of
Methane
Emissions
in
1995
FossilFuel
Consurnp~
iofl
coal~
dning
(2.6%)
Wastewater
(I
i.
5;;)
I
/
Trsatrnen!
.

(30.9%)
(­."
IO,

10
­­
US.
Climate
Action
Report
/
,
­.,
"­.

.
.~
'#
have
reduced
lan
1
methane
emissions
by
more
than
50
percent
(6.
'L
million
metric
tons
of
methane,
by
Source
in
1995
or
35.5
MMTCE).

MMT
MIMTCE
11.1
63.5
The
agricultural
sector
accounted
for
approxi­
9.6
54.8
3.6
20.4
mately
31
percent
of
total
US.
methane
emissions
i
n
Oil
andNatural
Gas
Systems
5.8
33.2
1995,
with
enteric
fermentation
i
n
domestic
livestock
Fossil
0.8
4.6
(34.9
MMTCE)
and
manure
management
(17.1
WastewaterTreatment
0.2
0.9
MMTCE)
together
accounting
for
the
majority
(Figure
3­
7).
Other
agricultural
activities
contributing
TOTAL
EMISSIONS
31
.O
377.3
directly
to
methane
emissions
include
rice
cultivation
*
­.
,.
.
.
Agriculture
.
.
......
...
....
.
..
...
."
.
­­
.
(2.5
MMTCE)
and
field
burning
of
agricultural
crop
Note:
All
methane
emission
estimates
are
preliminary.

*
One­
year
data
were
used
to
estimate
methana
emissions
from
rice
wastes
(0.04
MMTCE).

cultivationas
part
of
theAgriculturesector.
Correspondingvalues
for
the
Between
1990
and
1995,
methane
emissions
Agricultural
sector
using
lPCC
recommended
three­
year
averages
for
ricecultivationare:
9.3
MMT
and
53.2
MMTCE.
from
domestic
livestock
enteric
fermentation
and
manure
management
increased
by
about
7
percent
'

tion,
coal
mining,
the
production
and
processing
of
and
1
j
percent,
respectively.
During
this
Same
time
natural
gas
and
oil,
and
wastewater
treatment
(Table
period,
methane
emissions
from
rice
cultivation
3­
3
and
Figure
3­
6).
increased
by
about
10
percent,
while
emissions
from
field
burning
fluctuated.
Several
other
agricultural
Landfills
activities,
such
as
ihigation
and
tillage
practices,
may
Landfills
=e
the
largest
single
anthropogenic
contribute
to
methane
emissions.
However,
since
Source
of
methane
emissions
in
the
United
States.
Of
emissions
from
these
sources
are
uncertain
and
are
the
estimated
3,000
methaneeemitting
landfills
in
the
believed
to
be
small
the
United
States
has
not
in­
United
States,
1,300
account
for
about
half
ofthe
cluded
them
in
the
Current
inventory.
Details
on
the
emissions.
emission
pathways
included
in
the
inventory
follow.
In
an
environment
where
the
oxygen
content
is
Enteric
Fermentation
in
Domestic
Livestock
low
or
nonexistent,
organic
materials,
such
as
yard
(
.g
MMTC
waste,
household
waste,
food
waste,
and
paper,
are
During
animal
digestion,
methane
is
produced
decomposed
by
bacteria
to
produce
"2,
through
a
process
referred
to
as
enteric
fermentation,
and
stabilized
organic
materials
(materials
that
in
which
microbes
that
reside
in
animal
digestive
cannot
be
decomposed
further).
Methane
emissions
systems
break
down
the
feed
consumed
by
the
from
landfills
are
affected
by
such
specific
factors
as
animal.
In
1995,
fermentation
was
the
waste
composition,
moisture,
and
landfill
size.
of
about
20
percent
of
total
U.
S.
methane
emissions,
Methane
emissions
from
U.
S.
landfills
in
1995
and
about
64
percent
of
methane
emissions
from
the
were
63.5
MMTCE,
a
slight
increase
over
the
60
MMTCE
reported
in
the
previous
inventory.
Emis­
sions
from
U.
S.
municipal
solid
waste
landfills,
Figure
3­
7
which
received
over
59
percent
of.
the
total
solid
U.
S.
Sources
of
Agricultural
waste
generated
in
the
United
States,
accounted
for
Methane
Emissions
in
1995
about
90
to
95
percent
of
total
landfili
emissions,
while
industrial
landfills
accounted
for
the
remaining
Rice
Cultivation
waste
Bumin_
o
5
to
10
percent.
Currently,
almost
15
percent
of
the
methane
released
is
recovered
for
use
as
energy,
compared
to
10
percent
reported
in
the
last
inventory.
A
regulation
promulgated
in
March
1996
re­
quires
the
largest
U.
S.
landfills
to
collect
and
com­
bust
t
h
e
i
r
l
a
n
d
f
i
l
l
emissions
of
i3:
eric
Fernentation
nonmethane
volatile
organic
compounds
(VOCs).
It
(a
%)

is
estimated
that
by
the
year
2000,
this
regulation
will
Agricultural
"
,

Greenhouse
Gas
Inventory
­­
11
I
agricultural
sector.
This
estimate
34.9
MMTCE
is
the
same
as
that
reported
in
the
previous
inventory.

Manure
Management
(
.
MMTC
)

anaerobic
environment
produces
methane.
The
most
important
factor
affecting
the
amount
of
methane
produced
is
how
the
manure
is
managed,
since
certain
types
of
storage
and
treatment
systems
promote
an
oxygen­
free
environment.
In
particular,
liquid
systems
tend
to
produce
a
significant
quantity
of
methane,
whereas
solid
waste
management
approaches
produce
little
or
no
methane.
Higher
temperatures
and
moist
climatic
conditions
also
promote
methane
production.
Emissions
from
manure
management
were
about
10
percent
of
total
U.
S.
methane
emissions
in1995,,
and
about
31
percent
of
methane
emissions
from
the
agriculture
sector.
Liquid­
based
manure
management
systems
accounted
for
over
SO
percent
of
total
emissions
from
animal
wastes.
The
17.1
MMTCE
estimate
reported
here
is
slightly
above
the
13.7
MMTCE
reported
in
the
previous
inventory
because
of
larger
U.
S.
farm
animal
populations
and
expanded
use
of
liquid
manure
management
systems.

Rice
Cultivation
(
.
MMTC
)

United
States,
is
grown
on
flooded
fields.
The
soil's
organic
matter
decomposes
under
the
anaerobic
.

conditions
created
by
the
flooding,
releasing
methane
to
the
atmosphere,
primarily
through
the
rice
plants.
In
1995,
rice
cultivation
.was
the
source
of
less
than
2
percent
of
total
U.
S.
methane
emissions,
and
about
5
percent
of
U.
S.
methane
emissions
from
agricultural
sources.
Emissions
estimates
from
this
source
have
not
changed
significantly
since
1990.

Field
Burning
of
Agricultural
Wastes
,
The
decomposition­
of
organic
animal
waste
in
an
Most
of
the
world's
rice,
and
all
of
the
rice
in
the
(
.
MMTC
)
Farming
systems
produce
large
quantities
of
agricultural
crop
wastes.
Disposal
systems
for
these
wastes
include
plowing
them
back
into
the
field;
composting,
landfilling,
or
burning
them
in
the
field;
using
them
as
a
biomass
fuel;
or
selling
than
in
supplemental
feed
markets.
Burning
crop
residues
releases
a
number
of
greenhouse
gases,
including
C
q
,
methane,
carbon
monoxide,
nitrous
oxide,
and
oxides
of
nitrogen.
Field
burning
is
not
considered
to
be
a
net
source
of
carbon
dioxide
emissions
because
the
CQ
released
during
burning
is
reabsorbed
by
crop
regrowth
during
_­.

the
next
growing
sez
.
However,
this
practice
is
a
net
source
of
emissions
for
the
other
gases,
since
their
emissions
would
not
have
occurred
had
the
wastes
not
been
combusted.
Because
field
burning
is
not
common
in
the
United
States,
it
was
responsible
for
only
0.02
percent
of
total
U.
S.
methane
emissions
in
1995,
and
0.07
percent
of
emissions
from
the
agricultural
sector.
Estimates
of
emissions
from
this
source
have
dropped
significantly
since
the
last
inventory
as
a
result
of
new
research
indicating
that
a
smaller
fraction
of
U.
S.
crop
wastes
is
burned
than
previ­
ously
assumed.

Oil
and
Natural
Gas
Production
and
Processing
Methane
emissions
vary
greatly
from
facility
to
facility.
In
1995,
an
estimated
31.2
MMTCE
(or
approximately
I
S
percent)
of
U.
S.
methane
emissions
were
due
to
leaks,
disruptions,
etc.,
in
the
operation
and
maintenance
of
equipment
in
the
U.
S.
natural
gas
system.
This
figure
is
`significantly
higher
than
previous
estimates
because
of
revised
estimation
­

methods
that
improved
activity
factors
(i.
e.,
equip­
ment
counts)
and
emission
factors.
As
a
result,
natural
gas
systems
are
now
ranked
as
the
third
largest
source
of
U.
S.
methane
emissions.
Natural
gas
is
often
found
in
conjunction
with
oil
exploration.
Methane
is
also
released
during
the
production,
refinement,
transportation,
and
storage
of
crude
oil.
During
1995,
oil
and
gas
production
facilities
released
2.0
MMTCE
of
methane
to
the
atmosphere,
representing
about
one
percent
of
total
U.
S.
methane
emissions.

Coal
Mining
Produced
millions
of
years
ago
during
the
formation
of
coal,
methane
is
trapped
within
coal
seams
and
surrounding
rock
strata.
The
volume
of
methane
released
to
the
atmosphere
during
coal­
mining
operations
depends
primarily
upon
the
depth
and
type
of
coal
being
mined.
Methane
from
surface
mines
is
emitted
directly
coal
seam
are
removed.
Because
methane
in
under­
ground
mines
is
explosive
at
concentrations
of
5
to
15
percent
in
air,
most
active
underground
mines
are
required
to
circulate
large
quantities
of
air
and
vent
the
air
into
the
atmosphere.
At
some
mines,
methane­
recovery
systems
may
supplement
these
ventilation
to
ths
atizoaphers
X
thz
rock
stia;
d
ovzrlying
iiie
12
­­
U.
S.
Climate
Action
Report
­
,.
­.
,,

.­
.

systems
to
ensure
mine
saff
u.
S.
recovery
of
Agricult~
Soil
Management
and
methane
has
been
increasing
rn
recent
years.
During
Fertilizer
Use
1995,
coal
mining,
processing,
transportation,
and
consumption
activities
produced
an
estimated
20.4
MMTCE
of
methzne,..
pr
12
percent
of
total
U.
S.
methane
emissions.
This
lower
estimate
is
the
result
of
improved
mine­
specific
information
and
expanded
methane
recovery.
In
1995,
U.
S.
consumption
of
synthetic
nitrogen
and
organic
fertilizers
accounted
for
18.4
IMiMTCE,
or
approximately
46
percent
of
total
US.
p
emissions.
Other
agricultural
soil
management
practices,
such
as
irrigation,
tillage
practices,
or
laying
fallow
the
land,
can
~I
S
O
affect
fluxes
to
Other
Sources
and
from
the
soil.
However,
because
there
is
much
uncertainty
about
the
direction
and
magnitude
of
the
Methane
is
also
Produced
from
several
other
effects
of
these
other
practices,
only
the
emissions
sources
in
the
United
States,
including
energy­
related
from
fertilizer
use
and
field
burning
of
agricultural
combustion
activities,
wastewater
treatment,
indus­
lvnstes
are
included
i
n
the
U.
S.
inventory
a[
this
time,
trial
processes,
and
changes
in
land
use.
The
sources
included
in
the
U.
S.
inventory
are
fuel
combustion
`Fossil
Fuel
Combustion
and
wastewater
treatment,
which
accounted
for
approximately
4.6
and
0.9
MMTCE,
respectivelp
in
1995.
These
emissions
represent
about
3
percent
of
total
U.
S.
methane
emissions.
Additional
US.
anthropogenic
sources
of
methane
­­
such
as
ammo­
­
nia,
coke,
iron,
steel
production,
and
land­
use
changes
­­
are
not
included
because
little
information
on
methane
emissions
from
these
sources
is
currently
For
converters
installed­
to
a
v
a
i
l
a
b
l
e
.
.
promoted
the
formation
of
N?.
As
the
number
of
catalytic
converter­
equipped
;.
chicles
has
risen
in
the
U.
S.
motor
vehicle
fleet,
so
have
emissions
of
$dl
N,
O
is
a
product
of
the
reaction
that
occurs
between
nitrogen
and
oxygen
during
fossil
fuel
combustion.
Both
mobile
and
stationary
sources
emit
N,
O,
and
the
volume
emitted
varies
according
to
the
type
of
fuel,
technology,
or
pollution
control
device
used,
as
well
as
m$
intenance
and
operation
practices.

Nitrous
Oxide
Emissions
f
r
o
m
t
h
i
s
s
o
u
r
c
e
(DOEEIA,
1993b).

Nitrous
oxide
(N,
O)
is
a
chemically
and
radia­
In
1995,
N,
O
emissions
from
mobiIe
sources
tively
active
greenhouse
gas
that
is
produced
natu­
totaled
9.2
MMTCE
(or
23
percent
of
total
J$)

and
water.
While
50
emissions
of
are
much
lower
were
3*
0
than
CO,
emissions,
NP
is
approximately
310
times
more
powerful
than
C0,
at
trapping
heat
in
the
Adipic
Acid
Production
atmosphere
over
a
100­
year
time
horizon
(IPCC
The
vast
majority
of
all
adipic
acid
produced
in
1996).
the
United
States
is
used
to
manufacture
nylon
6,6.
During
the
past
two
centuries,
human
activities
N20
is
also
used
to
produce
some
low­
temperature
have
raised
atmospheric
concentrations
of
N,
O
by
lubricants,
and
to
add
a
"tangy"
flavor
to
foods.
approximately
8
percent
(Figure
3­
8,
Table
3­
4).
rally
from
a
\vide
variety
of
biological
Sources
in
soil
emissions),
and
Bo
emissions
from
stationary
The
main
anthropogenic
activities
producing
NQ
are
soil
management
and
fertilizer
use
for
agricul­
ture,
fossil
fuel
combustion,
adipic
acid
production,
and
nitric
acid
production
(seeTnble
3­
4
and
Figure
3­
8).
While
emissions
from
soil
management
and
fertilizers
remained
relatively
constant
during
1990­
93,
they
increased
during
1994­
95
because
of
intensified
fertilizer
applications
to
speed
recovery
of
nutrients
lost
to
the
1993
floods.
N,
O
emissions
from
all
other
sources
showed
no
significant
changes.
Table
3­
4
Agricultural
Soil
ivlanagerneni
and
Fertilizer
Use
Fossil
Fuel
Consumption
Adipic
Acid
Production
Nitric
Acid
Production
Agricultural
Waste
Burning
0.21
18.

0
12.
0
5
0
3
<
<

TOTAL
EMISSIONS
.
0.47
..

39.5
:

Greenhouse
Gas
Inventory
­­
13
Figure
3­
8
U.
S.
Sources
of
Nitrous
Oxide
Emissions
in
1995
Adpic
Acid
Nitrfc
Acid
pcductjon
Field
Burning
of
a
Agnkufturaf
Wastes
Fossil
Consumption
(31.4%)
Management
and
Fertilizer
Use
(46%)

In
1995,
U.
S.
adipic
acid
production
generated
5.2
MMTCE
of
nitrous
oxide,
or
13
percent
of
total
1995,
agricultural
bl
ng
contributed
approxi­
mately
0.01
MMTCE
of
N,
O
emissions
to
the
atmosphere.

land­
use
changes
because
of
uncertainties
in
their
effects
on
fluxes
in
IjO
and
trace
gases,
as
.well
as
poorly
quantified
statistics
on
them.
These
changes
include
forest
activity,
reclamation
of
freshwater
wetland
areas,
conversion
of
grasslands
to
pasture
and
cropland,
and
conversion
of
managed
lands
to
grasslands.
The
U.
S.
inventory
does
not
account
for
several
Emissions
from
HFCs,
PFCs
and
SF,
Hydrofluorocarbons
(HFCs)
and
eerfluorinated
U.
S.
N20
emissions.
By
1996,
all
adipic
acid
producdcompounds
(PFCs)
have
been
introduced
as
alterna­
tion
plants
in
the
United
States
are
expected
to
have
tives
to
the
ozone
depleting
substances
being
phased
N,
O
controls
in
place
that
will
reduce
emissions
up
out
under
the
Montreal
Protocoland
Clean
Air
Act
to­
98
percent,
compared
to
uncontrolled
levels.
(One­
Amendments
of
1990.
Because
HFCs
and
PFCs
are
halfof
the
plants
had
these
controls
in
place
and
not
directly
harmful
to
the
stratospheric
Ozone
layer,
operating
in
1995.)
they
are
not
controlled
by
thaMonrrea1
Protocol.
However,
these
compounds,
along
with
sulfur
­
Nitric
Acid
Production
hexafluoride
(SF,),
are
powerful
greenhouse
gases.
Nitric
acid
production
is
another
industrial
'
Therefore,
they
are
considered
under
the
United
Source
of
N,
O
emissions.
Used
primarily
to
make'
Nations'
Framework
Convention
on
Climate
Change
synthetic
co&
nercial
fertil­
izer,
this
raw
material
is
also
a
major
component
in
the
production
of
adipic
acid
and
explosives.
Virtually
all
of
the
nitric
acid
that
is
manufactured
commercially
in
the
United
States
is
produced
by
the
oxidation
of
ammonia,
during
which
r\
TO
is
formed
and
emitted
to
the
atmo­
sphere.
In
1995,
about
3.6
MMTCE
of
N20
were
emitted
from
nitric
acid
production,
accounting
for
9
percent
of
total
U.
S.
NQ
emissions.

Other
Sources
of
N,
O
Other
N,
O­
emitting
activities
include
the
burning
of
agricultural
crop
residues
and
changes
in
land
use.
In
C?.
FP%!!!!!

HFCs
HFC­
23
HFC­
1
25
HFC­
134a
HFC­
143a
HFC­
152a
HFC­
227
HFC­
4310
PFCs
CF4
C2Fs
C4FlO
c6F14
PFCs/
PFPEs'

s
F6
....
..
MMT
of
Gas
0.02071
0.00426
0.00227
0.01
086
0.00004
0.00091
0.001
86
0.00051
.......

~0.00410
0.00250
0.00057
0.00001
<
0.00001
0.00102
0.001
29
.......
Atmospheric
GWP
.........
Lifetime
(yrs)
...
.....
Vrdue
__
"TCE
20.92
264
11,700
33
2,800
15
1,300
48
3,800
2
140
37
2,900
17
1,300
7.93
50,000
6.500
10,000
0.200
2,600
7,000
3,200
7,400
7
3,200
23,900
8.40
'PFCIPFPEs
are
a
pro4
for
many
diverse
PFCs
and
perfluoropolyethers
(PFPEs)
which
are
beginning
to
be
employed
in
solvent
applications.
GWP
and
lifetime
values
are
based
upon
c6F1:.

14
­­
US.
Climate
Action
Report
­
//
,
/
.?

Emissions
of
CFCs
and
Related
Compounds
..

­.
....
Chlorofluorocarbons
(CFCs)
and
other
halogenated
compounds
were
f
this
century.
This
family
of
human­
made
compounds
includes
CFCs,
ha1
tetrachloride,
methyl
bromide,
and
hydrochlorofluorocarbons
(HCFCs).
T
variety
of
industrial
applications,
including
foam
production,
refrigeration
cleaning,
sterilization,
fire
extinguishing,
paints,
coatings,
other
chemical
miscellaneous
uses
(e.
g.,
aerosols
and
propellants).

Because
these
compounds
have
been
shown
to
deplete
stratospheric
to
as
ozone­
depleting
substances
(ODSs).
In
addition,
they
are
importa
they
block
infrared
radiation
that
would
otherwise
escape
into
space
(IP
Recognizing
the
harmful
effects
of
these
compounds
on
the
atmosph
signed
the
MontrealProtocolon
Substances
3
consumption
of
a
number
of
them.
As
of
Apr
M
United
States
furthered
its
commitment
to
phase
out
these
substances
by
signing
and
ratifying
th
Copenhagen
Amendments
to
the
Montreal
Protocol
in
1992.
Under
these
amendments,
the
U.
S.
committed
to
eliminating
the
production
of
halons
by
January
1,
1994,
and
CFCs
by
January
1,
1
The
IPCC
Guidelines
do
not
include
reporting
instructions
for
emissions
of
ODSs
because
their
use
is
being
phased
out
under
the
Montreal
Protocol.
Nevertherless,
because
the
United
States
believes
that
no
inventory
is
complete
without
these
emissions,
estimates
for
emissions
from
several
Class
1
and
Class
II
ODSs
are
provided
here:
Compounds
are
classified
according
to
their
ozone­
depleting
potential
and
must
adhere
to
a
strict
set
of
phase­
out
requirements
under
the
Montreal
Protocol.

Class
I
compounds
are
the
primary
ODSs;
Class
I
I
compounds
include
partially
halogenated
chlorine
compounds
(HCFCs),
some
of
which
were
developed
as
interim
replacements
for
CFCs.
Because
these
HCFC
compounds
are
only
partially
halogenated,
their
hydrogenkarbon
bonds
are
more
vulnerable
to
oxidation
in
the
troposphere
and,
therefore,
pose
only
about
one­
tenth
to
one­
hundredth
the
threat
to
stratospheric
ozone,
compared
to
CFCs.

Also,
the
effects
of
these
compounds
on
radiative
forcing
are
not
provided
here.
Although
CFCs
and
related
compounds
have
large
direct
global
warming
potentials,
their
indirect
effects
are
believed
to
be
negative
and,
therefore
could
significsntiy
reduca
tha
magnitude
of
their
direct
effects
(IPCC
1992).
Given
the
uncertainties
surrounding
the
net
effect
of
these
gases,
they
are
reported
here
on
a
full
molecular
weight
basis
only.
........
Compound
~

".

Ch55
/Compounds
CFC­
11
CFC­
12
CFC­
113
CFC­
I
14
CFC­
I
15
Carbon
Tetrachloride
Methyl
Chloroform
Halon­
1211
Halon­
I301
Chs5
//
Compounds
HCFC­
22
HCFC­
123
HCFC­
124
HCFC­
141
b
HCFC­
142b
­
Emissions
"
.

0.036
0.052
0.01
7
0.002
0.003
0.005
0.046
0.001
0.002
0.092
0.002
0.005
0.01
9
0.020
Greenhouse
Gas
Inventory
­­
15
Emissions
of
Criteria
*

Pollutants
­
Table
3­
6
shows
that
fuel
consumption
accounts
for
the
majority
of
emissions
of
these
gases.
In
fact,
motor
vehicles
that
bum
fossil
fuels
contributed
In
the
United
States,
carbon
monoxide
(CO),
approximately
81
percent
of
all
U.
S.
CO
emissions
in
nitrogen
oxides
(NCI),
nonmethane
volatile
organic
1995.
Motor
vehicles
also
emit
more
than
a
third
of
compounds
(NMVOCs),
and
sulfur
dioxide
(SQ)
are
total
U.
S.
NOx
and
NMVOC
emissions.
Industrial
commonly
referred
to
as
'(
criteria
pollutants."
CO
is
processes
­­
such
as
the
manufacture
of
chemical
and
produced
when
carbon
containing
fuels
are
burned
allied
products,
metals
processing,
and
industrial
incompletely.
Oxides
of
nitrogen
(NO
and
NC;
3
are
uses
of
solvents
­­
are
also
major
sources
of
CO,

created
by
lightening,
fires,
fossil
fuel
combustion,
,
NOx,
and
NMVOCs.

and
in
the
stratosphere
from
nitrous
oxide.
NMVOCs
~

­­
which
include
such
compounds
as
propane,
butane,
and
ethane
­­
are
emitted
primarily
from
transporta­
tion
and
industrial
pro­
cesses,
as
well
as
forest
wildfires
and
nonindustrial
consumption
of
organic
.
solvents.
And
SO,
can
result
from
the
combustion
of
fossil
fuels,
industrial
processing
(particularly
in
the
metals
industry),
waste
incineration,
and
biomass
burning
(U.
S.
EPA
1996).
1995
Emissions
of
CO,
NOx,
NMVOCs,
and
SO
..
(MillionMetricTonnes):
.
.

sources
......
­.
..
­.
....
....
"T
.....
._.:
.......
...
E?.
ox
....
MUTCE
­
"_
.
,
..
.....

Fossil
Fuel
Combustion
70.95
.
18.75
8.22
Industrial
Processes
5.15
0.71
4.13
Solvent
Use
'
<
0.01
<
0.01
5.80
Waste
Disposal
and
Recycling
1.60
0.01
2.1
9
Other
Combustion
5.86
0.21
0.41
TOTAL­
'.
....
..

....
83.55
.;
19.?
3
20.74
...
...
i
.
...

so2
1473
1.83
<
0.01
0.03
0.01
......
.....
"

.......

16.60
....
..
...

16
­­
US.
Climate
Action
Report
"_

B
O
?
3­
3
Sources
and
Effects
of
Sulfur
Dioxide
..

Emitted
into
theatmosphere
through
natural
and
human
processes,
SO2
affects
the
Earth's
radiative
budget
through
photochemical
transformation
into
sulfate
particles
that
(1)
scatter
sunlight
back
to
space,
thereby
reducing
the
radiation
reaching
the
Earth's
surface;
(2)
possibly
increase
the
number
of
cloud
condensation
nuclei,
thereby
potentially
altering
the
physical
characteristics
of
clouds;
and
(3)
affect
atmospheric
chemical
composition
­­
e.
g.,
atmospheric
ozone
­­
by
providing
surfaces
for
heterogeneous
chemical
processes.
As
a
result
of
these
activities,
the
effect
of
these
SO2
emissions
on
radiative
forcing
is
likely
negative
(IPCC
1996),
although
the
distribution
is
not
uniform.

SO2
is
also
a
major
contributor
to
the
mix
of
urb3n
air
pollution,
which
can
significantly
increase
acute
and
chronic
respiratory
diseases.
Once
SO2
is
emitted,
it
is
chemically
transformed
in
the
atmosphere
and
returns
to
the
Earth
as
the
primary
source
of
acid
rain.
Because
of
these
harmful
effects,
the
United
States
has
regulated
SO2
emissions
in
the
Clean
Air
Act
of
1970
and
its
subsequent
1990
amendments.

Electric
utilities
are
the
largest
source
of
SO2
emissions
in
the
United.
States,
accounting
for
about
66
percent
of
total
SO2
emissions
in
1995.
Coal
combustion
contribute3
approximately
96
percent
of
those
emissions.
SO2
emissionshave
significantly
decreased
in
recent
years,
as
electric
utilities
have
increasingly
switched
to
lower­
sulfur
coal
and
natural
gas.
The
second
largest
source
is
fuel
combustion
for
metal
smelting
and
other
industrial
processes,
which
produced
about
20
percent
of
1995
SO2
emissions
(U.
S.
EPNOAQPS).
/

I
"

I
IPCC.
34.
Clinrnte
Change
1994:
Radiative
Forcing
of
Climate
Change
and
an
Evaluation
of
the
IPCC
IS92
Emission
Scenarios;
J.
T.
Houghton,
L.
G.
Meira
Filho,
J.
Bruce,
Hoesung
Lee,
B.
A.
Callander,
E.
Haites,
N.
Harris,
and
K.
Maskell,
Eds.;
Intergovernmental
Panel
on
Climate
Change:
Cambridge;
pp.
1­
34.

IPCC.
1996.
Climrie
Change
1995:
Tj2e
Science
of
Clin~
ate
Change;
J.
T.
Houghton,
L.
G.
hleira
Filho,
B.
A.
Callander,
N.
Harris,
A.
Kattenberg,
and
K.
Maskell,
Eds.;
Cambridge
University
Press.
Cambridge,
U.
K.

IPCC/
OECD/
IEA/
UNEP.
1995.
IPCC
Guidelines
for
Nariond
Greenhorlse
Gas
Inventories,
Vol.
3,
Reference
Manual;
Intergovernmental
Panel
on
Climate
Change,
Organization
for
Economic
Co­
Operation
and
Development,
Internatjonal
Energy
Agency,
United
Nations
Environment
Program:
­
Brecknell,
UK;
pp.
Preface
l­
Overview
7.

US.
EPA.
1995.
bwentory
of
US.
Greenhouse
GAS
Emissions
and
Sinks:
1990­
1994;
Office
of
Policy,
Planning
and
Evaluation,
Washington,
D.
C.

U.
S.
EPA.
1996.
National
Air
Pollutant
Emission
Trends,
1995,
Office
of
Air
Quality
Planning
and
Standards,
Washington,
D.
C.

U.
S.
EPA.
1997.
draft
of
Inventory
of
U.
S.
REFERENCES
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States
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Emissions
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the
United
States:
1985
­
1990.
U.
S.
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Washington,
D.
C.
DOE/
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0573.

DOEEIA.
1996a.
Emissions
of
Greenhouse
Gases
in
the
United
States
1995;
Energy
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Administration,
U.
S.
Department
of
Energy,
JJ'ashington,
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C.
DOEEIA.
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1995;
Energy
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U.
S.
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of
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Climate
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1992:
The
Supplementary
Reporr
to
the
IPCC
Scientific
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Press,
Cambridge,
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Greenhouse
GAS
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and
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i99$
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of
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and
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Washington,
D.
C.

United
States
Forest
Service
(USFS).
1990An
Analysis
of
rhe
Timber
Sirmrion
in
the
United
States:
1989
­
2040:
A
Technical
Document
Supporting
the
1989
USDA
Forest
Service
RPA
Assessment.
Forest
Service,
United
States
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of
Agriculture.
General
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I­
199.
Seki,
M.,
Christ,
R.
1995.
African
Regional
Wrkshop
on
Greenhoirse
G
~J
En1ission
Inventories
and
Emission
Mitigation
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Forestv,
Land­
use
Change
and
Agricrdturc
Uh'EP.

Greenhause
Gas
Inventory
­­
17
PUBLIC
HEALTH
EmCTS
OF
CLIMATE
CHANGE:
SYNTHESIS
OF
THE
lPCC
FINDINGS"

Jonathan
A.
Patz,
MD,
MPH
Department
of
Envifo
ental
Health
Sciences
&
Department
of
Molecular
%
cmbidogy
and
Immundgy
Johns
Hopkins
School
of
Hygiene
and
Public
Health
Statement
prepared
for
a
Roundtable
Discussion
of
SENATOR
JCSEPW
I.
UEElERMAN
United
Scates.
Senate,
June
11,1996
Plaintiff
1
4
1
0
9
5
5
1
8
1
1
0
.6
­1
0
­9
6
.
02:
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2
.
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.
....
.....
....
..*.­
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*
Public
Health
­
Effects
Of
Climate
Change:
Synthcsts
Of
The
IPCC
Findings
Pak,
J.
A.

ABSTRACT
Climatologists
have
identified
upward
trends
in
global
temperatures
and
m
w
estimate
a
rise
of
2.
WC
by
the
year
2100.
Of
major
concern
in
the
health
community
is
that
these
changes
can
cause
an
increase
in
both
direct
and
i
n
d
k
m
health
outcomes
such
as:
1)
mortality
and
morbidit
dated
to
heatwaves
and
increased
urban
air
pollution;
2)
re­
emergmce
of
serious
vector­
borne
in
ty
&om
diseases:
3)
spread
of
water­
borne
diseases
from
hydrological
extremes
and
elevated
sen
surfsce
temperatures;
4)
malnutrition
from
t
h
r
e
a
t
e
n
e
d
food
supply;
and
5)
general
public
health
infrastrucrural
damage
from
weather
disasters
and
sea­
level
rise.

Temperatures
above
threshold
levels
andlor
particular
types
of
air
masses
can
be
directly
hazardous
to
human
health,
musing
mortality
in
vulnerable
populations.
Infectious
agents
which
cycle
throughcold­
blooded
insect
vectors
to
complete
their
development,
however,
tend
to
be
sensitive
to
very
subtle
climate
variations.
In
temperate
&ions,
climare
change
wouId
affect
vector­
borne
diseases
by
altering
the
vectoT's
range,
reproductive
and
biting
rates,
as
well
as
pathogen
development
rate
within
the
vector
host
For
example,
the
geographic
mge
of
malaria
is
gmedly
limited
to
the
tropics
and
subtropics
because
the
PIamroditium
parasite
requins
an
average
temperature
above
16"
C
to
develop
Freezing
temperatures
kill
overwintering
eggs
of
Aedes
mgypzi,
the
mosquito
canier
of
dengue
and
yellow
fever,
and
warmer
temperatures
shorten
dengue
virus
extrinsic
incubation
periods,
potentially
accelerating
transmistdon
rates.
­

Climate­
related
increases
ia
sea
surface
temperature
can
lead
to
higher
incidence
of
water­
borne
cholera
and
shellfish
pisoning,
Marine
phytoplankton
blmm5
include
red
tides
that
cause
diarrheal
and
paralytic
diseases.
Vibrio
choler&
has
been
found
to
be
associated
with
marine
zooplankton,
and
blooms
from
warmer
sea
surfacetempwatures
could
expand
this
important
reservoir
from
which
chdera
epidemics
may
arise.

Human
migration
and
damage
to
health
infi­
ashuctures
from
the
projected
increase
in
climate
variability
and
severity
of
storms
could
thMen
human
shelters
and
public
health
infrastructures
and
indirectly
contribute
to
disease
tratlstnission.
Furtkmore,
projected
increases
in
extremes
of
the
hydrologic
cycle
can
impact
diarrheal
diseases;
drought
in
developing
countries
compromises
personal
hygiene,
while
flooding
in
developed
agricdtwal
areas
can
increase
exposure
to
Cryptosporidim.
Human
susceptibility
to
disease
might
be
further
compounded
by
regioN
matnutritiondue
to
climate
impacts
on
agriculm,
and
perhaps,
by
immunosuppression
caused
by
in­&
flux
of
ultraviolet
radiation
due
to
stratospheric
m
e
depletion.
Elite&
of
stratospheric
omne
depletion
may
act
synergistically
with
health
outcomes
of
Climate
change,
though
the
chlorofluombon
chemical
destruction
of
strawspheric
omne
is,
for
the
most
part,
a
different
anthropogenic
process
than
is
g
r
~~h
o
~~e
warming
(climate
change).

Analyzing
the
dosts
d
climate
change's
influence
on
human
diseases
will
require
interdiscipIinW
cooperation
and
must
account
for
both
disease
burden
and
costs
of
adaptation
and
prevention,
Internenlions
can
occur
at
varying
points
along
disease
camation
and
each
level
carries
vatying
costs.
Generally,
steps
are
more
cost­
effective
when
occurring
early
in
the
course
of
disease
progression;
indeed,
considering
the
irreversibk
nature
of
some
of
the
health
hazards
associated
with
clinak
change,
upa~
caa
intervention
strategies
maybe
particularly
beneficial
in
this
case.
Inkmali~
nal
d
i
w
sweiliance,
in
wmbination
with
ecological
and
ciimablogical
monitoring
will
afford
more
anticipatory
measures
ta
optimize
proactive
preventive
measures.
Integral&
assessments
at
multiple
geographic
levels
and
~CTOSIS
varying
sc=
ctms
are
necessary
to
better
understand
climatological
and
ecologiCat
change
as
determinants
of
human
health.

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R­
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Table
of
Contents
INTRODUCTION
Nature
of
tire
Probkem
ANTICIPATED
HEALTH
IMPACT
OF
CLIMATE
CHANGE
Heat=
reluted
Morbidity
and
Morlaliiy
Climate,
Air
Pollution
Vuctar­
borne
Diseases.
lL&
zlmh
Dengue
and
Dengue
Hmrrhagic
Fever
Other
Vecm­
bormDkeases
MaAm
Ecology:
Cholera
&
Toxic
Algae
Agriculture
I
Human
Nutrition
Sea
Level
Rise,
Extreme
Weather
Events
and
Climate
Vcviabiflty
Stratospheric
Ozone
Depletion:
Spaergistic
Impacts
on
Hetiiih
CUmate
Obrenntions
for
Zhe
U.
S.
Hsaf­
related
Mortuk'tg
­
US.
Vector­
borne
Diseases
­
U.
S.
Waterborne
Diseases
­
US.
costs
to
t
h
U.
S.
POTENTIAL
HEALTH
IMPACTS
IN
THE
UNITED
STATES
RECOMMENDATIONS
integruted
Apptoacher
To
Improvs
The
Asfessment
Of
Health
Impacts
Levels
of
Prevention:
the
Public
Health
Model
CONCLUSION
3
4
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..
­.
..
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..
.
.
.
..
.
..
,INTRODUCTION
The
first
assessment
report
of
the
Intergovernmental
Panel
on
Climate
Change
(IPCC)
focused
on
natural
and
managed
resources,
such
as
forests,
agriculture,
coastal
mnes
and
fisheries;
initially
there
was
little
attention
given
to
the
public
health
effects
of
climate
change.
While
it
is
clear
that
the.
health
af
human
populations
depends
on
these
sectors,
only
recently
have
public
health
scientists
become
concerned
abuut
the
mare
primary
effects
of
greenhouse
warming
on
human
diseases.
The
debut
of
a
chapter
dedicated
to
human
health
in
the
Second
Assessment
Report
of
the
IPCC
ROW
provides
a
platform
on
which
to
focus
further
efforts
in
this
field.

The
World
Health
Organization
(WHO)
has
been
integrally
involved
with
the
writing
of
the
population
health
chapter
uf
IPCC.
In
several
weeks
the
WHO
will
release
its
own
major
monograph,
"Climate
Change
and
Human
Health,
'
which
expands
upon
the
findings
highlighted
by
tbe
IPCC
(WHO,
in
press).

Nature
of
the
Problem
According
to
the
health
chapter
af
the
IPCC
Second
Assessment
Report
("
ichaet
et
al.,
1gg6),
the
scale
ofthe
anticipated
health
impacts
is
that
of
whole
cornmunitm
orpop~~
Iations
dm
than
at
the
individual
level.
Human
health
impacts
would
occur
via
pathways
of
varying
directness
and
complexity,
including
distuhce
of
naturai
and
managed
ecrrsystems.
Research
to
this
point
mostly
has
been
qualitative,
with
the
exception
of
recent
studies
on
heat
mortality
and
mathematid
modeling
of
infectious
diseases.
Qualitatively,
however,
the
aggregate
b
d
health
implications
­
are
of
major
concern
and
are
presently
receiving
far
more
attention
from
the
medical
and
public
health
communities,
including
agencies
and
imtitutions
such
as
the
Cenbers
for
D
i
m
e
Control
and
Prcvcntion,
the
Environmental
Protection
Agency,.
the
National
Institutes
of
Health,
the
institute
of
Medicine
and
?he
National
Academy
of
Science
as
examples.

Most
of
ihe
impacts
are
expected
to
be
adverse,
though
regionally
some
areas
may
benefit.
Some
J
impacts
would
occur
via
relatively
direct
ways,
such
as
from
heatwaves
and
floods;
others
would
occur
via
less
direct
pathways,
changes
in
habitat
that
may
define
the
distribution
of
dime­
carrying
insects.
Some
impacts
would
be
deferred
in
time
and
would
QCCW
on
a
largq
&e
than
most
other
environmental
health
impacts
with
which
we
are
familiar.
If
long­
t
e
r
m
clime
change
mues,
indirect
impads
would
probably
predominate.
These
represent
public
health
problems
at
a
relatively
new
level
of
sde,
being
glow
geographically
and
placing
p
p
l
a
t
i
m
­rather
than
individuals­
at
risk.
Furthermore,
as
the
health
impacts
likely
would
occur
wef
an
extended
time
scale,
it
will
be
diffidt
to
discern
them
from
natural
variation,
making
&
h
e
f
i
t
s
of
early
preventive
measurn
more
difficult
to
identify.

ANTICIPATED
HEALTH
IMPACT
OF
CLIMATE
CHANGE
The
main
physical
components
anticipated
from
climate
change
are:
1)
tempemhue
elevation
with
concomitant
precipitation
changes;
2)
=­
level
rise
(primarily
from
thennoexpansion
of
oceans);
and
3)
extreme
weather
events
­
rticularly
in
the
hydrologic
cycle,
e.
g.,
flaxis
and
droughts
(Houghton
et
at.,
19%).
These
c
E
n
ges
may
lead
to
an
increased
frequency
of
heat
waves
and
potentially
hazardous
air
pollution
episodes,
reduced
soil
moisture,
severe
sbms
and
coastal
flooding.
Subsequent
health
effects
may
include
an
increase
in:
1)
heat­
related
ri.
r.
odity
2.
d
morbidity;
2)
vector­
borne
diseases,
e.
g.,
carried
by
insects
or
small
rodents;
Sj
water­
borne
diseases
both
from
f
l
d
i
n
g
and
from
altered
marine
ecology;
4)
malnutrition
from
threatened
food
and
water
supply;
and
5)
general
public
health
infrastructurd
damage
from
weather
disasters,
sea­
level
rise,
and
forced
human
migration
(see
figwe
1).

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2
He&­
related
Morbidity
and
Moriality
,
Although
humans
have
a
great
capacity
to
adapt
to
adverse
environmental
conditions,
them
m
limits
to
physiologic
accommodation
(Kilboumt,
1989).
Weather
conditions
exceeding
threshold
temperatures
and
petsiating
for
several
consecutive
days
can
cause
increased
mentality
in
the
population.
In
lwge
urban
areas,
poor
housing
combined
with
the
urban
"heat
islend"
effect
further
women8
ccr~~
iitions.
'
Hevated
night­
time
teinperatwe
readings
­offering
no
relieffM
'.

oppressive
daytime
heat
­
m
the
most
significant
meteoroiogical
variable
mtrihuting
to
heat­
related
mortality;
the
greenhow
effect
is
predtded
to
especially
a.
f€
ect
these
minimum
tenqxranrres
(Kalkstein
&
Smoyer,
1993).
Higher
latitudes
are
ex­
d
to
w
m
disproportionately
more
than
tropical
and
subtropical
zones.

According
to
the
IPCC
report
(MeMichael
et
al.,
1996),
the
frequency
of
extremely
hot
days
in
temperate
climatea
would
approximately
double
far
an
increase
of
2­
3°
C
in
the
average
summw
temperature
(CDC,
1989;
C
l
m
t
e
Change
Impacts
Review
Group
UK,
1W1).
Extensive
research
has
shown
thal
heatwaves
cause
excess
deatha(
Weihe,
1986;
Kilbourne,
1992),
many
of
which
are
due
to
i
n
c
r
e
a
s
e
d
demand
on
the
cardiovasculgg
system
required
for
physiologic
cooling.

Death
rates
in
temperate
and
subtropical
zones
are
higher,
however,
in
winter
than
in
summer
(Kilboume,
1992)
and
it
is
a
reasonable
expectation
that
milder
winters
in
such
countries
would
entail
a
reduction
in
cold­
related
deaths
and
illnesses.
Yet,
summer­
related
deaths
appear
to
be
more
related
to
temperature
extremes
than
are
winter­
related
deaths
that
may
be
m
a
a
function
of
.
indmr
confinement
with
increased
contact
to
infectious
agents
such
as
respiratory
viruses;
this
expected
reduction
in
winter
mortality
may
not
fully
offset
the
heat­
related
incteases
(McMcW
et
­
al.,
199r5).

Mortality
f
r
m
extreme
h
t
is
increased
by
crmcomitanr
conditions
of
low
wind,
high
humidity
and
intense
solar
radiation
(Klbourne,
1992).
These
meteordogid
elements
have
ken
treated
synoptically
or
wholistidly
as
one
approa&
to
evaluate
the
net
effect
of
weather
on
human
health.
f
i
r
example,
recent
studies
in
the
US.
have
described
"offensive"
air
masses
which
represent
synoptic
meteorological
situations
statistically
associated
with
human
mortality.
TIris
approach
recognizes
that
humans
principally
res@
to
the
envelope
of
air
that
surrounds
them
(Kalkstein,
15­
93},
It
should
also
be
m
d
that
concurrent
hot
weather
and
air
pollution
have
synergistic
impacts
on
health
(Katsouyanni
et
al.,
1993).

Climate
and
Air
Pollution
climate
change
can
indirectly
alter
urban
air
pollution
by
altering
local
weather
patterns
(Scott
et
ai.,
1%),
and
atmospheric
chemical
reactions.
l3qxsure
to
air
pollutants
has
broad
public
health
implications.
Chronic
expure
to
o
m
e
bas
been
shown
to
exambate
asthma
and
impair
lung
function
in
children
and
the
elderly
and
chronic
expure
to
fine
particles
is
a
came
of
excess
deaths
and
morbidity
(Dockery
et
aL,
1993;
Pope
et
al.,
1995).
Over
1
billion
people
are
exposed
to
excessive
particulate
levels
and
nearly
900
million
are
expDsed
to
unhealthy
levels
of
sulfur
dioxide
{Scott
et
al.,
1M).

Under
the
conditions
of
global
warming,
air
pollution
exposure
may
be
exacerbated
given
cunent
trends
in
urbanization,
combined
with
increasing
fossil
fuel
combustion,
Warmer
tempratlrres
canbind
with
inc&
ambient
ultraviolet(
UV)
radiation
could
worsen
air
pollution,
especially
over
urban
areas.
UV­
photodecompsition
of
nitrogen
oxides
(NOx)
in
the
presence
d
volatile
organic
compounds
(VOC)
results
in
the
secondary
prduction
of
Voposphehc
mme.
Such
increases
in
photochemical
smog
formation
will
likely
cause
health
hazards
in
semi­
wid,
suqny
citics
such
as
Los
Angela
and
Mexico
City
(Scott
et
al.,
1%).
Adding
to
health
hazards
of
this
type
of
air
pollution,
concentrations
of
allergenic
ajrborne
pollen
may
change
with
vegetation$
response
to
a
shifting
climate
regime
and
to
the
"fertilization"
effect
afforded
by
higher
atmospheric
CCQ
levels.

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Vector­
borne
Direures
,
Infectious
diseascsare
still
the
world's
leading
cause
of
fatalitiea
killing
over
17
million
people
annually
(WHO,
1996).
Vector­
borne
diseases
(primarily
carried
by
i
n
s
e
c
t
M
small
mammal
"vectors')
and
water­
borne
diarrheal
diseases
represent
a
large
proportion
of
these,
For
example,
according
to
the
WHO
report,
last
year
malaria
alone
killed
2.1.
million
and
diarrheal
diseases
k
i
l
l
e
d
3.1
million,
most
being
children.

I
t
is
well
recognized
that
climate
conditions
directIy
affect
disease
vector
andlor
parasite
biology,
as
dmentrxl
below.
In
addition,
however,
climate's
indirect
health
impact
OD,
regional
food
supply
with
subsequent
nutritional
status
and
on
forced
human
migration
may
substantially
alter
susceptibility
to
infections
as
well.
It
is
also
imperative
to
view
climate
change's
e
f
k
t
s
within
the
cuntext
of
other
key
determinants
of
disease,
such
as
swioeconomic
or
cultural
factors,
to
better
evaluate
population
vulnerability.

Bacteria,
viruses
or
parasites
which
cyde
ttuough
cold­
bWed
insect
vectors
to
complete
their
development
are
quite
sensitive
to
subtle
climauvariations
(Dobson
&
Carper,
1993).
Temperature
determines
vector
infectivity
by
affecting
ogen
replication,
maturation,
and
the
period
d
infectivity
(Longstreth
&
Wiseman,
1989).
Epatfi
evated
temperature
and
humidly
d80
intensify
the
biting
behavior
of
most
inseds.
Table
18.3
from
the
fFCC
repwt
summarim
widespread
vector­
borne
diseases
and
rankB
their
l
k
l
i
h
d
of
being
influenced
by
climate
&w
e
.

Disease
carried
by
small
dents,
whose
populations
strongly
depend
on
their
surrounding
environment,
also
likely
would
respond
to
climate­
related
ecological
change.
br
example,
the
­
pulmonaiy
hantavirus
epidemic
in
the
southwest
U
S
was
felt
to
be
due
to
an
upsurge
In
rodent
pulations
related
to
climate
and
ecological
conditions
(Wenzel,
1994).
Six
years
of
drought,
!%
owed
by
cxtremely
heavy
spring
rains
in
1993,
resulted
in
a
10­
fold
increase
in
the
population
of
deer
mice,
which
can
carry
hantavirus
(Stme,
1993;
Levins
et
at,,
1994).

Floods
and
hurricanes
also
significantly
affect
vector­
he
diseases.
More
aquatic
breeding
sim
for
mosquitos
translates
into
higher
insect
population
densities.
Moreover,
destruction
of
shelters
leaves
human
ppulations
more
likely
to
come
into
contact
with
infective
mosquitoes.
Simultaneously,
Infect&
humans
exped
to
the
elements
beccmne
a
more
readily
wccessitae
reservoir
of
dieease
from
which
epidemics
may
be
fueled
by
the
mosquitoes
which
feed
upon
them.
,.
_:

Two
of
the
world's
most
widespread
~ector­
born~
dim
are
malaria
and
dengue
fever.
These
are
highlighted
below
as
illustrative
examples
of
h
o
w
climate
change
can
strongly
influence
disease
transmission.
Bear
in
mind,
however,
that
other
determinants
of
disease
must
be
considered
simultaneously
to
determine
site­
specific
poplation
vulnerability
to
the
altered
risk
potentid.

Malaria,
­
Malaria
is
the
most
prevalent
vector­
borne
disease
globally,
and
causes
350
million
new
c
~s
e
s
and
2
million
deaths
annually
(Institute
of
Medicine,
1991).
Control
of
malaria
has
been
disappointing
and
the
number
of
cases
annually
is
increasing.
Malaria
generally
occurs
throughout
the
tropics
and
subtropics
primarily
because
the
malaria
parasite
cannot
develap
inside
its
mosquito
h
a
t
at
temperatuns
below
16°
C
(GilIes,
1993).

Temperature
and
humidity
are
among
the
most
important
determinants
of
disease
transmission
and
the
exbinsic
incubation
period
of
the
parasite
shortens
dmnatidy
at
ternprztwes
krween
20"­
27°
C
(Ncden
et
al.,
1995;
Gilles,
1993).
The
extrinsic
incubation
period
(EIP)
is
defined
as
the
number
of
days
between
the
vector's
ingestion
of
an
infected
Mood
meal
and
the
point
that
i
t
becomes
capzble
oftransmi#
ing
infection,
Climatic
factors
that
increase
the
inoculation
rate
of
Plamrodiwn
pathogens,
as
well
as
Che
breeding
activity
of
Anopheles
mosquitoes,
are
considered
the
most
important
cause
of
epidemic
outbreaks
of
malaria
in
nm­
endemic
areas
(Gilles,
1993).

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Unseasonably
bot
w
e
e
r
has
been
found
to
increase
malaria
transmission,
for
example,
in
,
Pakistan
(Bouma
e€
al.,
1994),
and
bas
been
associated
with
malaria
occurring
at
higher
altitudes
in
Rwanda
(Loevinsohn,
1994)
Under
climate
change
scenarias
(Martcsns
et
al.,
1995;
Matsu&
a
&
Kai,
1993,
risk
of
malaria
epidemics
would
rise
subtantially
in
both
t
r
o
p
i
c
a
l
and
temperate
regions.
More
than
one
million
additional
fatalities
per
year
is
estimated
to
be
attributed
to
dimrite
change
by
the
middle
of
the
next
century,
according
to
a
model
developed
by
Martens
et
al.,
which
is
cited
in
the
lPCC
report
(Martens
et
al.,
1994).

Change
in
disease
di6tribUtiOn
itself
may
be
significant,
let
done
inCreased
mdaria
cases.
F;
or
example,
large
u
r
h
highland
populations
in
the
tropics
(ego,
Nairobi
and
Harare)
that
are
~Q
K
endemic
for
malaria
are
also
immunologically
naive
to
the
disease;
fhese
populations
are
at
far
greater
risk
of
serious
illness
than
are
populations
where
malaria
currently
occurs
Ipatr;
et
d.,
19%).

Dengue
andDengcre
Hemonha
ic
P
e
w
.
­
Over
the
past
15
years,
epidemics
of
dengue,
or
breakbone
fever'
­
an
extreme
f
y
painful
ff
u­
like.
illness
­
have
increased
in
both
number
and
severity,
especially
in
tmpid
urban
centers.
Dengue
hemcxrhagic
fever
(DHF),
a
more
sex­
iow
variant
of
dengue,
usually
associated
with
second
infections
of
dengue
virus,
now
ranks
as
one
of
the
leading
causes
for
hospitalization
and
mortality
of
children
in
Southeast
Asia
(Institute
af
Medicine,
lm),
and
i
s
on
the
risein
the
Americas
(Gubles
&
Trent,
1994;
PAHO,
19%).
Urbanization,
inadequate
mosquito
contrd,
aLsence
of
water
systems,
and
international
travel
m
migration
m
major
factors
leading
to
the
reemergence
of
dengue
(PAHO,
1994;
Gubler
&
Clark,
1995).
Climate
conditions,
however,
contribute
to
epidemic
Spread
and
geogmphic
distribution
­
(Macdonald,
1956;
Reiter,
1988).

The
range
of
the
primary
mosquito
vector,
Ae&
s
mgypri,
(which
also
carries
yellow
fever)
is
limited
because
freezing
temperam
kill
bofh
larvae
and
adults.
Warming
trends,
therefore,
may
shift
vector
and
disease
distribution
to
higher
latitudes
and
altitudes.
In
Mexico
in
1986,
the
must
important
predictor
of
local
dengue
transmission
was
found
to
be
the
median
tempe­
e
during
the
rainy
season
(Koopman,
et
al.,
199l),
and
dengue
was
observed
in
Mexico
at
w1
unprecedented
altitude
of
1,700
meters
during
an
unseasonably
warm
summer
in
1988
(Henera­
Basto
et
al.,
1992).

Temperature
also
affects
the
transmission
dynamics
of
dengue.
Warmer
temperatures
reduce
mosquito
larval
size
(Rueda
et
al.,
1990).
Smaller
hatching
adults
must
feed
more
frequently
to
develop
EUI
egg
batch
(Macdondd,
29%;
Scott
et
al.,
1993),
boosting
the
incidence
Of
multiple
reeding
within
each
egg­
laying
cycle
(Macdonald,
1956;
Pant
Lk
Yasuno,
1973).
Additionally,
viral
development
inside
th.
e
r
n
a
q
u
i
t
o
shortens
with
higher
ternpratures
(Watts
et
al.,
1987;
&iter,
1sK18),
increasing
the
pmpOmm
of
mosquitoes
that
become
infectious
at
a
given
time
(Fock3
et
d.,
1995).
In
summary,
higher
temperature
leadrr
to
more
infectious
mosquitoes
that
bite
more
frequently.

Ohher
Vecmr­
barn
Dkeares.
­­
Onchccerciasis,
or
Viver
blindness",
is
a
prevalent
form
of
blindness
caused
by
a
helminth
(or
worm)
infection,
Canid
by
blackflies,
it
is
primarily
found
in
West
Africa
and,
to
a
lesser
extent,
in
Latin
America.
Climate
plays
an
important
role
in
the
Occurrence
of
onchocerciasis
since
the
vector
requires
fast­
flowing
water
for
successful.
reproduction,
and
the
adult
vector
can
be
spread
by
wind
(WHO,
1935).
A
recent
st~
dy
found
khp~
if
temperature
and
precipik~",.
chzqg
LTW
pi+
hrs
of
Mest
Africa
as
?r&
ict&
by
some
GCMs,
blacMly
populations
may
increase
by
as
much
as
25%
at
their
current
breeding
s
i
b
(Nils,
1995).
Pokntial
abmdonment
of
agricultural
land
in
river
valleys
could
add
to
regional
food
production
problems
(patz
et
al.,
1996).

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African
trypanosomiasis,
or
incuable
and
usUatIy
fatal
nslceping
sichess"
is
canied
by
tsetse
,
flies,
whose
distribution
depends
on
vegetation
cover.
Researchers
in
s~~
bsahamn
Africa
have
correIated
vegetation
type
to
the
population
densitics
of
tsetseflies
using
s
a
t
e
l
l
i
t
e
images
to
predict
a
large
extension
of
regions
at
risk
for
this
disease,
assuming
a
3°
C
temperatwe
rise
in
mean
monthly
temperature
(Rogers
&t
Randolph,
1991
&
1993).

Tick­
borne
diseases
are
also
eeasitive
to
climatic
conditions
but
favor
cooler
temperatures.
In
Africa,
Rogers
and
Randolph
found
mean
monthly
maximum
temperature
to
be
the
shongest
predictor
of
tick
occumnce
at
the
margins
of
endemic
zones
(Rogers
Packer,
1993).
OnIy2"
C
determined
the
difference
between
arm
where
tick$
are
present
or
absent
in
southeastern
Africa.
In
the
southern
US,
Rocky
Mountain
Spotted
Fever
may
decline
due
to
ticks'
intolerance
of
high
temperanves
and
diminished
humidity
(Haile,
1989).

Murine
Ecology:
Cholera
&
Toxic
A
l
p
Over
the
past
century,
average
sea
surface
temperature
has
increased
approximately
0.7T
(Haughton
et
al.,
1992),
and
marine
growth
of
dgae
has
been
observed
to
respond
to
localized
temperature
increases
in
nutrient
replete
waters
(from
fertilizer
runoff
and
sewerage
release).
warm
water
favors
the
growth
of
dinoflagellates
and
cyanobacteria
(Valiela,
1984),
that
include
rnw
toxic
organisms
such
aa
red
tides,
which
cause
paralytic
shell
fish
poisming,
diarrheic
sheU
fish
poimning.
and
amnesiac
shell
fish
poisoning.
Thw,
climate­
induced
changes
in
the
production
of
both
aquatic
pathogens
and
biotoxins
may
jeopardize
s
d
d
safety
for
humans,
sea
m
m
&,
seabirds,
and
fin­
fish
(McMichael
et
al.,
1996).

Zooplankton,
which
feed
on
algae,
can
m
e
as
reservoirs
for
VibriochoZerae
and
other
enteric
pathogens,
particularly
gram­
negative
mis
(Epstdo,
1995).
Latge
coastal
blwms
may
have
conaibuted
to
the
recent
mulriepicentered
choIera
epidemic
in
Latin
America.
Quexmt
forms
of
V.
cb2era.
e
have
been
found
to
persist
wittxini
algae
that
a
n
revert
to
a
culturslble
(and
likely
infectiuus)
state
when
nutrients,
pH,
and
temperature
permit
(Huq
et
al.,
1990).
With
warmer
sea
s
u
f
a
c
e
temperatures,
cmstal
algal
blooms
may
therefore
p
n
t
i
a
t
e
cholera
proliferation
and
transmission.
­

Agriculhue
1
Human
Nutrition
Climate
change
could
adversely
affect
agriculture
both
by
long­
term
changes,
such
as
r
e
d
u
c
i
n
g
soil
moisture
though
evapotranspiration,
and
more
immediately,
by
extreme
weather
events
such
as
droughts,
flooding
(and
erosion)
and
tropical
storms
(Meams,
1993).
Sealevel
rise
couldafkct
fd
production
thrwgh
the
combhation
of
inundation
and
i
n
c
r
e
a
s
e
d
salinity
of
coastal
farmlands
(Haines
&
Pany,
1993).
"C
q
fertilization,"
on
the
other
hand,
enhances
photosynthesis
and
may
initially
benefitplants
(Tegart
et
al.,
1%).
Increases
in
the
intensity
of
rainfall
in
some
regions
wouId
exacerbate
soil
erosion.
The
net
global
impact
of
these
climate­
relatedchanges
upon
food
production
is
highly
uncertain
(Reilly,
1994).
While
productivity
in
some
regions
may
increase
initially,
longer­
term
adaptations
to
sustained
climate
change
may
be
less
likely
because
of
the
limitations
of
plant
phy8iology
(Woodward,
19B7),
and
water
availability.

According
to
the
IFCC
report,
cljrnak
change
could
also
affect
agriculture
by
long­
term
changes
in
agmmysterns
and
by
altered
patterns
of
plant
di­
and
pest
infestations
(IvIcMichael
et&
19%).
C.@
fertilization
would
affect
differently
the
two
major
metabolic
categories
of
plants:
the
C3
plants
(e.
g.,
wheat,
soya
beans,
rice,
and
p
o
t
~t
c
m
)~
which
worlr!
I
Y
~~X
K
!
psiE;
tz!
y,
and
~2
C4
plants
(e­
g.,
millet,
sorghum,
md
~iizc),
mb~
ch
tvauld
lx
UiLaff~
ted.
Such
infiuences
on
ttK
climatically
optimal
mix
of
crop
s
p
e
c
i
e
s
would
disturb
patterns
of
saditional
agiculture
in
some
regions
(McMichad
et
al.,
19%).
Controlling
for
CQ
fertilization,
a
study
involving
30
nations
nevertheless
estimated
that
40
­
300
million
additional
peop­
le
worldwide
could
be
at
risk
from
hunger
due
to
climate
change
(Parry
&
Rosenzweig,
1993).

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22
Sea
Level
Rise,
Extreme
Weather
Event:
and
Climate
YarsabiUty
Sea
Level
Rise.
­­
According
to
the
IPCC
rem,
much
of
coastal
B
a
n
g
l
W
and
of
Egypt$
heavily
populated
Nile
Delta
would
lx
flooded.
For
example,
a
sca­
level
rise
of
one
meter
would
destroy
IS%
and
20%
of
agridhlre
in
Egypt
arxl
Bangladesh
respectivsly
(Tegart
et
al.,
1990).
Some
low­
lying,
small
island
stam
such
as
the
Maldives
and
Vanuatu
would
be
at
risk
of
mal
immersion
and
many
other
low­
lying
coastal
regions
(for
example,
eastern
England,
parts
of
Indonesia,
Louisianna,
and
parts
of
the
northeast
coast
d
Latin
America)
would
be
wlnerable.
The
displacement
of
inundated
communities
­
prtic~
1Iar1
thaw
with
limited
economic,
t
e
c
h
n
i
c
a
l
,
and
social
T~
SOUK'RS
­
would
grcatIy
incttase
the
risks
o
Y
various
infectious,
psychological,
and
other
adverse
h
d
t
h
consequences
(McMichA
et
al.,
1996).
3
­

Other
health
effects
of
sea­
level
rise
include
the
disruption
of
stormwater
drainage
and
sewage
disposai,
compromised
sanitation
and
displacement
of
coastal
dwdlen.
Saline
intrusion
ofcoastal
aquifers
a
u
l
d
diminish
fresh
water
supply
and
coastat
farmland
in
addition
to
frank
inundation.
In
many
plares,
industrial
and
agricultural
depletiwof
groundwater
are
already
causing
land
subsidence,
thus
decreasing
the
threshold
for
impiszt.
Some
changes
in
the
distribution
of
infectious
disease
vectors
could
occur
(e+.,
Anopheles
sundajcus,
a
salt­
water
vector
of
malaria)
(McMichael
and
et
al.,
1996),

Extreme
W
e
a
k
Events,
­­
More
frequent
extreme
weather
events
are
predicted
to
accompany
global
warming,
due
in
part
to
increases
in
convective
activity
(Whetton
et
al.,
193).
More
intense
rainfall
events
accompanying
global
warming
(fcazi
et
al.,
1995),
would
be
expected
to
increase
tbe
­
occurrence
of
floods,
and
warmer
sea
sutface
temperature$
can
be
expected
to
strengthen
tropical
cyclones
(Houghton,
Meira
Filho
et
at,,
19%).
Severe
storms
can
caw
direct
physical
hann
to
humans
as
well
as'disrupt
public
health
infmnucture,
cawing
contamination
of
water
systems.
Meanwkile,
heavy
storms
create
breeding
sites
for
insects
or
favorable
conditions
for
rodents
that
carry
diseases.
Destruction
uf
shelters
leavehuman
populations
more
exposed
to
infectious
vecton,
increasing
the
potential
for
epidemics.

Climatic
effects
on
the
distribution
and
quality
of
surface
water,
inchding
increases
in
flaxling
andlor
water
shortages,
can
impede
personal
hygiene
and
impair
locaf.
sewerage.
Subsequent
risks
of
dimheal
(including
cholera)
and
dysentery
epidemics,
parhcularly
in
developing
wunaies
would
be
expected
to
ensue
(McMichael
et
al,,
1996).
Diarrheal
diseases
can
be
caused
by
a
large
variety
of
bacteria
(e.
g.,
Salmonella,
Shigella
and
Campylobacter),
viruses
(e.
g.,
Rotavim),
and
protozoa
(e.
g.,
Giardia
lamblia,
amoebas,
and
Cryptosporidium).
In
addition,
expected
intensification
of
heavy
rainfall
even&
could
lead
to
more
rapid
leaching
from
hazardous
waste
landfills
which
are
not
watertight
(Scott
et
d,,
19%).
Toxic
contamination
of
groundwater
or
swface
drinking
water
would
then
pose
a
local
health
threat,

Human
migration
away
from
coastal,
rural
or
other
economically
or
physically
vuinerabte
k~
xti0n~
j
could
be
anricipated.
Already,
droughts
have
fared
mass
migrations
in
West
Africa
and
other
parts
of
the
world,
compounding
upward
trends
in
urbanization
(Scott
et
al.,
19%).
Also,
many
infectious
disease
endemic
regions
throughout
the
tropics
and
subtropics
have
been
identifified
being
vulnerable
to
an
increase
in
extreme
weather
events
(Patz
&
Balbus,
1996).
The
potentid
risk
of
epidemics
could
increase
in
urt3an
settings
as
refugees
anive
from
disease
eridemic
areas
(Leaf,
1989;
Hainw
&
FUC~
B,
1991).
Already,
current
h
n
d
s
in
urbanization
incmx
the
p
~e
~f
i
d
for
disease
epidemics
such
as
cholera
and
dengue
fever.

C
I
W
e
Variability.
­­
Same
of
the
anticipared
health
impacts
associated
with
extreme
climate
variability
are
already
within
the
range
of
arrent
human
experience.
Many
disease
outbreaks
have
lzeen
asscw=
iated
with
the
erratic
wearher
conditions
driven
by
El
Nido
Southem
Oscillation
(ENSO)
events.
ENSO
is
a
climate
phenomenon
that
is
second
only
to
seasod
cycles
in
i
t
s
i
m
p
&
on
regional
climate
variability
(Nicblls,
I%),
and
OCCUT
on
average
every
four
years
(Kifadis
&

9
R=
98%
C
1
0
9
5
5
1
8
1
1
06­
10­
95
0
2
:0
7
P
f
*l
P
O
1
0
#22
Dias,
1989).
Anomalous
fluctuations
in
precipitation,
even
to
the
extent
of
flaxIs
or
droughts,
,
known
to
result
from
climate
variations
ifluenoeri
by
ENS0
events.

Exbeme
heavy
Istinfalls
havebeen
c
o
r
r
t
l
a
t
e
d
with
outbreaks
of
Munay
Vally
encephalitis
and
Ross
River
virus
in
Australia,
eastern
equine
encephalitis
in
the
US
(Nicholls,
1993),
West
Nile
k
v
e
r
in
southern
Africa
(Glantz
et
al.,
1991),
cyclical
malaria
epidemics
in
Argentina
(Macdonald,
1941),
and
Wstan
(Zulueta,
lW),
Such
climate­
related
outbreaks
have
closely
cumpod
to
ENSO
cycles,
which
are
now
thought
to
be
the
driving
force
behind
these
geographical2y­
speuf1c
extreme
climaticconditions
(Nicholls,
1991;
Bquma
et
al.,
1994).
Maria
can
also
be
associated
with
droughts
linked
to
ENS0
phenomenon
­when
rivets
pool
­
in
Sri
Lanka
(Bouma
et
d.,
1994).
The
devastating
drought
in
countries
of
the
Indian
Ocean
region
in
the
past
several
years
has
been
attributed
to
a
persistent
El
Nifio
as
well
(Glantz
et
al.,
1992).

Sbatorpheric
Orsns
Depletion:
Synergistic
Im
acts
on
Health
Some
consider
stratospheric
ozone
depletion
(Molina
8pRowlmd,
1974),
accompanied
by
increases
in
ambient
biologically
destructive
ulmviolet­
B
radiation
(UV­
B)
(Ken
&
McElroy,
1993),
alongside
climate
change,
though
it
arises
from
a
different
anthropogenic
process
than
does.
the
greenhouse
effect.
Partial
justification
stems
from
the
fact
that
chlorofluorocwbns
(CFCs),
other
halocarbons
and
methyl
bromide
are
themselves
pdent
greenhow
gases.
Mormvw,
the
h
a
t
trapping
effect
of
greenhouse
gases
in
the
atmosphere
results
in
reduced
amounts
of
heat
reaching
t
h
e
stratosphere;
suhstsquent
increases
in
ice
crystal
formation
in
the
uppr
stratasphere
serves
catalyst
for
Further
destruction
of
the
m
e
layer.

The
d
i
r
e
c
t
health
impacts
from
increases
in
UV­
B
include:
1)
skin
cancer;
2)
cataract
and
dhw
ocular
diseases:
and
3)
immunosuppression.
Indirect
effects
to
health
may
occur
primarily
tbugh
UV­
mediated
crop
damage
and
by
photochemical
formation
of
tropospheric
ozone
(at
the
ground
level
as
opposed
to
in
the
stratosphere).
alluded
to
within
the
previous
section
on
air
pollution.
Immunauppressim
cwld
exacerbate
several
of
the
health
outcomes
from
geedm
warming,
especially
infectious
disease
epidemics,
­

Regarding
cancer,
it
is
estimated
that
for
a
sustained
10%
decline
in
the
stratospheric
ozone
layer,
non­
melanoma
skin
cancer
cases
could
rise
by
26%,
or300,000
globally
per
year;
mclanoma
could
increase
by
2096,
or
4,500
more
cases
mually
(UNEP,
1Srgl).
UV­
B
radiation
has
also
been
associated
with
ocular
cataract
formation
(Taylor,
1990);
cataracts
m
u
n
t
for
half
of
all
blindness
in
the
world.
A
10%
sustained
loss
of
stratospheric
ozone
would
result
in
nearly
1.75
million
extra
cataractsannually
(UNEP,
1991).

UV­
induced
immunosuppression
may
exacerbate
the
effect
of
climate
change
on
infectious
diseases,
particularly
diseases
of
the
skin
such
as
onchocerciasis
and
dermatophytosis
(fungal
infections),
and
diseases
where
the
skin
is
a
portat
of
entry
as
in
leishmaniasis
(Giannini,
1990).
UV
light
has
been
shown
to
cause
immunosuppmsion
in
both
animal
and
human
studies
(Jeevan
62
Kripke,
1990;
Larcom
et
al.,
19%);
B
a
w
d
,
1991;
UNEP,
1591;
Cooper
et
d.,
1992;
IARC,
1992;
Kripke,
1m;
Cestari
et
al.,
1!
295).
UV­
B
impairs
antigen
p
m
s
i
n
g
and
presentation
by
Langerhan
cells
in
the
skin
(Wolff
&
Sting,
1983;
Cruz
&
Betgstresser,
1988;
Morison,
1989),
as
well
as
altering
lymphokine
pfcductian,
which
reduces
T­
hlperlT­
supprwor
cell
ratios
at
the
systemic
level
(Noonan
et
al.,
1981;
DeFabo
&
Nmm,
1983;
Hersey
et
a].,
1983;
Kripke
&
Morison,
1986;
Daynes,
1990).
In
shoh,
i&
UV­€
3
expasure
may
augment
ihe
potential
fw
disease
emergence
and
dissemination
by
!owering
human
L
r
n
1
~­
defer.
sB,
:...
..
.>

POTENTIAL
HEALTH
IMPACTS
IN
THE
UNITED
STATES
'

While
most
of
the
health
effects
described
above
apply
throughout
many
parts
of
the
world,
a
few
are
particularly
relevant
dommticaUy,
Climate
change
has
been
implicated
in
the
continental
US.
and
clc"
examination
of
resultant
health
effects
should
follow.

10
4
1
0
9
5
5
1
8
1
1
R­
98%
0
6
­1
0
­9
6
02:
07P?
d
P
o
l
l
#2
2
Health
and
Climate
Change
,
CIimnie
obssrvdwnr
for
the
U.
S.
Climatic
data
for
the
U.
S.
reveal
changes
and
variations
that
may
be
significant
to
human
morbidity
and
mortality.
Since
the
turn
dthe
century
average
daily
temperature6
in
the
contiguous
U.
S.
have
increased
by
approximately
0.4"
C,
with
most
of
t
h
i
s
i
n
c
r
e
a
s
e
occurring
during
the
past
30
years
(Karl
et
at.,
199%).
Recent
studies
have
shown
that
the
hydrologic
cycle
in
the
U.
S.
is
changing
as
indicated
by
increases
in
cloud
cover
(Karl
&
Steurer,
1990)
and
precipitaticm
(Gmisrnan
&
Easterling,
1994)
and
decreases
in
pan
evapmdion
(Petenson,
1995).
Extremes
in
U.
S.
precipitation
have
been
changing
with
increases
in
heavy
precipitation
events
and
~~e
s
in
lighter
precipitatian
events
(Karl
et
al.,
199%;
E
M
et
al.,
1996).
Using
data
back
to
1910,
Kixl
et
al.
found
that
the
most
recent
15
y
m
had
the
highest
values
of
Greenhouse
Climate
Response
Index
(GCRI)
as
well
as
Climate
Extremes
Index
(Cn).
It
is
becoming
increasingly
apparent
that
measurable
changes
in
climate
rrends
are
occurring
in
the
U.
S.

Heat­
related
Mottuliiy
­
US.
Temperate
regions,
such
as
the
US,
are
o
warm
disproportionately
more
than
tropical
and
subtropical
zona
@FCC,
1990).
of
c
o
n
m
t
meteorological
and
mortality
data
in
cities
in
the
USA,
Canada,
the
Netherlands,
China,
and
the
Middle
East
provide
wnflmatory
evidence
that
overall
death
rates
rise
during
heat
wave8
(Kalkstein
&
Smoyer,
1991;
Kunst
el
id.,
1W),
particularly
when
the
temperature
rises
above
the
I
d
population's
threshold
value.

Using
data
from
Philadelphia
for
the
years
1973
through
1988,
Samet
et
al,,
found
a
rdatimship
­
between
temperature
and
humidity
and
daily
mortality
counts
through
regression
rncdels
(Samet
et
al.+
19%).
Long­
term
trend
and
increasing
variability
both
may
be
incmpomd
into
models.
The
tcmm
relationship
between
temperature
and
mortality,
was
also
found
to
have
differing
time
lags
for
hotter
and
colder
regions
of
the
U.
S.;
and
the
magnitude
of
the
health
risk
is
age­
dependent.

In
the
IPCC
report,
the
population
of
Atlanta
wax
given
as
an
example
of
expected
change
in
heat­
related
mortality
(McMichael
et
d.,
1996).
Presently,
Atlanta
experiences
an
average
of78
k
t
­
related
deaths
each
summer.
Under
the
climate
projections
of
the
GmL
1989
(transient)
climate
change
GCM
model,
and
assuming
no
change
in
population
size
or
age
rofile,
this
number
would
increase
to
191
in
the
year
2020,
and
to
293
in
the
year
2050.
With
popu
P
ation
acclimatization,
the
annual
total
excess
mortality
is
96
and
147
respectively.
Under
the
T
"R
(transient)
model
m,
the
cwresponding
four
projectiohs
of
heat­
related
mortality
are
20­
40?
6
higher
than
for
the
aFDL
model
run:
247
and
436
deaths
(unacclimatized,
2020
and
2
0
5
0
)
and
124
and
218
deaths
(acclimatized,
2020
and
2050).
These
and
other
results
for
selected
North
American
cities
indicate
that
the
annual
number
of
heat­
nlated
deaths
would
approximately
double
by
2020
and
would
increase
several­
fold
by
2050.

Vector­
borne
dioeaoer
­
U.
S.
Mosquito­
borne
diseases,
­
Currently,
dengue
viruses
are
being
transmitted
in
the
npics
between
300
north
and
200
south
latitude,
(Trent
et
al.,
1983)
sinm
frosts
or
mtaiXKd
cold
wealher
kills
a
d
u
l
t
mosquitoes
and
overwintering
eggg
and
larvae
(Chandler,
1945;
Shope,
1991).
hem
averages
10,
OOO
dengue
fever
cases
annually,
and
dengue
now
occu~;
s
in
nearly
all
Caribkn
nations
and
Mexico,
and
periodically
has
been
endemic
inTexas
in
the
past
two
d
d
e
s
.
h
e
to
the
climate
sensitivity
of
dengue
a
dp,.
criM
ir,
&t&
i
a
b
l
e
,
this
disPae
ma;.
f
~h
r
~hka
*"
ti:
southern
U.
S.
with
climate
change.
Endemic
malaria
also
cxmsionally
arises
in
the
U.
S.
and
has
recently
been
reported
in
Texas,
New
Y
ork
and
New
Jersey
during
unseasonably
hot
summers.

Of
reported
encephalitis
cases
in
the
US.,
most
are
mquito­
borne
and,
in
order
of
prevalence
in
the
U.
S,,
include:
Saint
Louis
and
Lacrosse
encephalitis,
and
western,
e
a
s
t
e
r
n
,
and
Venezuelan
11
R=
98%
4
1
0
9
5
5
1
8
1
1
0
6
­1
0
­9
6
02:
07Pb!
PO12
#2
2
equine
encephalomyelitis
(Shop,
1980).
Clinical
features
range
from
headache
to
frank
,
m~
e@
ditis,
with
the
elderiy
at
highest
risk
for
mortality.
Though
mosquito
longevity
diminishes
as
pmpratures
rise,
viral
transmission
rates
(similar
to
dengue)
rise
sharply
at
higher
temperatures
'

(see
figure
2)
(Hardy,
1988;
Reisin
et
al,,
1993).
From
field
studies
in
Callfonnia,
(Reeves
et
d.,
1994)
researchers
predict
that
a3­
5'C
temperature
increase
will
caw
a
significant
northern
shift
in
both
western
equine
and
Saint
Louis
encephalitis
outbreaks,
with
disappearance
of
western
equine
in
southern
endemic
regions.

Human
outbreaks
of
Saint
io&
s
encephalitis
are
highly
ux"
dai&
d
With
severalday
periods
when
temperature
exceeds
85OF(
30"
C)
(Monath
&
Tsai,
19$
7),
as
was
the
case
during
the
1984
California
epidemic
thal
followed
a
period
of
extremely
high
temperatures.
Computer
analysis
of
monthly
climate
data
has
demonstrated
that
excessive
rainfall
in
January
and
February,
in
combination
with
drought
in
July,
most
often
precedes
outbreaks
(Bowen
&
Francy,
1980).
Such
a
pattern
of
warm,
wet
winters
followed
by
hot,
dry
summers
resembles
the
GCM
projections
for
climate
change
over
much
of
the
U.
S.
(Schneider,
1990;
Houghton,
Meita
Filho
et
al.,
1996).

Tick­
borne
diseuses.
­
Ticks
transmit
Lyme
disease,
the
most
commonvector­
bme
disease
in
the
U.
S..
with
more
than
10,
OOO
cam
in
1994,
along
with
Rwky
Mountain
Spotted
Fever,
and
EMidhiosis,
which
is
rapidly
emerging
disease.
Involved
tick
and
mammal
hwt
ppulatians
are
influenced
by
land
uselland
cover,
soil
type,
elevation,
and
the
timing,
duration,
and
rate
of
change
of
temperature
and
moisture
regimes
(Glass
et
al.
1994;
Mount
et
al.,
1!
393).
The
relationships
between
vector
life
stage
pameters
and
climatic
conditions
havebeen
verified
experimentally
in
both
field
aod
laboratory
studies
(Mount
et
al.
1993,
Ooddard
1992).
Climate
change,
therefore,
­
could
be
expted
to
alter
the
diatxibution
of
these
diseases.

Waterborne
Diseases
­
US.
Cryptosporidiosis
causes
severe
diarrhea
in
children
and
can
be
fatal
to
immuncmmpromised
individuals
and
i
s
the
most
prevalent
wakrbrne
disease
in
the
U.
S.
(Mwe
et
al.,
1994).
The
disease
is
a
zoonosis
associated
with
dairy
farms,
domestic
stock
and
water
associated
contamination.
Natural
events
(eg.
floods,
storms,
heavy
rainfall,
snow
melt,
and
swollen
fivers)
wash
material
of
fecal
origin,
primarily
fm.
agricultud
non­
point
sources
into
potable
water.
The
Milwaukee
outbreak
in
1993
resulted
in
4U3,
ooO
reported
cases
and
coincided
with
unusually
heavy
spring
rains
and
runoff
from
melting
snow
(WcKemie
et
al.,
1994).
The
five
best
documented
waterborne
outbreaks
of
nyptosporidiosis
in
the
U.
S.
were
caused
by
bath
cmtantinatim
of
water
mums
relared
to
aberrant
weather
and
operational
deficiencies
ofthe
water
treatment
facilities
(Lisle
&Rose,
l!
XB).

Factors
enhancing
waterbane
Cryptosporidiosis
will
depend
on
hydrological
responses
to
climate
change
snd
degree
of
flooding
in
water
catchment
areas.
Land
use
pattern
determine
agricultw
contamination
sow=
and
must
therefore
be
considered.
Watekbm
diseases
also
will
k.
affected
by
salinity
change
from
sea
lev4
rise.
In
freshwater,
the
q
s
t
dieoff
rate
is
relatively
hi&
but
saline
water
extends
oocyst
viability
of
this
protozoan
(Lisle
&
Rose,
1995).
important
implications
for
coastal
recreational
waters
contaminated
with
sewage
and
runoff
material
containing
Cryptosporidirun
oocysts
and
concomitantly
experiencing
salinity
changes
secondary
to
sea
level
rise.
4
Cholera
and
red
tides,
as
previously
described,
re
sensitive
to
changes
in
marine
ecology
related
io
ciimate
change,
For
example,
one
species
of
toxic
algae
previously
mnfined
to
the
G
d
f
of
Mexico,
G'ymnaditu'um
breve,
extended
northward
in
1987
after
a
"parcel
of
warm
gulf
stream
water"
reached
fu
up
the
East
Coast
resulting
in
human
neurologic
shellfish
poisonings
and
substantial
fishkills
(Tester,
1991).
Cholera
m
u
m
in
the
Gulf
of
Mexico
and
human
cases,
which
dready
cccur
in
the
U.
S.,
may
increase
as
sea
temperatures
w
m
.

12
X=
98%
4
1
0
9
5
5
1
8
1
1
0
6
­1
0
­9
6
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2
:0
7
P
M
P
O
1
3
#22
Cogts
to
the
US.

a
~llness
associated
with
climate
change,
whether
it
resultsin
acute
or
chronic
morbidity
effects
or
in
mortality,
irnpoaes
multiple
costs
to
society:
fox
treatment
(incIuding
medical
care,
drugs,
and
hospitalization);
lost
work
days
and
lowered
productivity:
and
reduced
quality
of
life.
Farmany
climaterelated
illnesses,
costs
may
also
be
incurred
to
prevent
the
spread
of
illness
and
reduce
health
impacts
and
associated
costs.
Such
prevention
programs
include
va:
tw­
control
actjvitieg,
such
a
eliminating
breeding
pIaces
or
applying
insecticides
to
animals
or
houses.
Prevention
can
also
take
the
form
of
widespread
immunization
or
monitoring
and
watch­
warning
systems
Varying
levels
of
mts
will
parallel
the
multipk
points
of
intervention
along
the
continuum
of
disease
devcloprnent.
In
general,
"an
ounce
of
prevention
is
worth
a
pound
of
cure,"
since
end­
stage
trcatment
options
are
nearly
always
more
costly
than
proactive
measurn.

Unintended
costs
of
control
measures
must
be
considered,
as
well.
For
example,
the
adverse
effects
on
public
health
and
the
environment
resulting
fram
gene&
pesticide
use
are
estimated
to
CQSt
between
$100
billion
and
$200
billion
arrsually
worldwide
(Pimend,
1990).
Pesticides
not
only
involve
direct
human
toxic
effects,
but
a
l
s
u
t
~y
lead
to
insect
resistance
and
reduction
in
natural
predatory
organisms.
Mosquito
resistance
has
been
"extremely
costly''
with
regards
to
malaria
control
(Pant,
1987),
and
more
than
50
species
have
developed
resistance
to
i
n
s
e
c
t
i
c
i
d
e
since
1947
(Brown,
1983).
Risks
to
American
military
personnel
overseas
and
to
the
tourist
industry
impose
additional
cos6
on
the
US.;
230,
OOO
cases
of
malaria
were
diagnosed
in
Vietnam
veterans
(Institute
of
Medicine.
1992).

RECOMMENDATIONS
Integrated
Approaches
to
Impruve
the
'Arsssrment
of
Health
hpacts
Most
human
diseases
that
stem
from
hazardous
environmental
expoSUres
are
multifacrorid.
Many
of
the
primary
determinants
of
human
healtki
(a
d
q
u
a
food,
clean
water
and
secure
shelter)
are
related
to
&e
outcomes
of
sectors
such
as
agriculture,
water
resources
and
fisheries.
In
populations
suffering
malnutrition
problems,
the
effect
of
climate
change
on
agricultural
production
may
have
a
greater
adverse
effect
on
human
health
than
any
given
disease.
Therefore,
it
is
important
to
integrate
these
relevant
systems
into
the
human
health
assessment.

One
should
also
realize
that
it
may
not
be
possible
to
make
firm
predictions
of
climate­
related
alterations
in
disease
incidence
for
two
main
reasons,
First,
at
a
global
level,
the
anticipated
climate
changes
are
beyond
the
range
of
recorded
observations,
and
therefore,
we
have
no
direct
evidence
of
human
disease
under
these
new
conditions
(McMicM,
19%)
(though
the
site­
specific
studies
referenced
throughout
this
ppet
clearly
show
disease
sensitivity
to
climate
conditions).
Second,
we
have
a
long
way
to
go
in
our
understanding
the
dynamics
between
climate,
ecological
change,
and
human
health,
which
reduces
our
confidence
in
extrapolating
from
historical
observatians,
For
these
reasons,
mathematicat
mcdels
can
be
useful
where
empirical
observations
are
unavailabie.
A
number
of
integrated
models
are
cumntly
under
development
for
such
diseases
as
dengue
and
malaria
(Fmks
et
al.,
1993;
Jetten
8c
Takken,
1994;
Martens
et
al.,
1994).

For
specific
health
assessments
at
the
local
level,
geogra
hically
organized
data
is
h
o
m
i
n
g
increasingly
more
useful
in
environmental
exposure
stu
(E
'es.
Examples
of
&ul
analytical
toois
include:
1)
geographic
information
systems
(GIS)
to
organize
gm­
gaphimlly­~
disex­,
climate
and
demographic
data;
and2)
remote
*!
k.
se,
nSng
txhnology
Wpoyidzs
tduabli:
data
on
land
use
patterns,
habitat
characteristics,
and
marine
ecosystems
(Glass
et
al.,
1993).
In
m
n
t
studies,
GIS
and
remote
sensing
were
used
to
identify
weas
receptive
to
dengue
fever
a
d
Lyme
disease
in
the
U.
S.,
schistosomiasis
in
Egypt
and
the
Philippines,
and
malaria
in
temperate
rice
growing
regions
(Glass
et
al.,
1993;
Washino
&
Wood,
1994).

R­
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13
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1
0
9
5
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#22
An
essential
ste
in
recognizing
and
thereby
preventing
adverse
health
outoomes
i
s
enhanced
,surveillance
amfresponse.
Early
detectim
~1
1
not
only
provide
an
early
warning
fm
possibly
more
pervasive
changes
in
d
i
m
behavior
and
allow
for
intervention,
but
will
also
enrich
our
knowledge
of
dimate­
related
diseases
and
facilitate
?he
creation
of
better
predictive
models,

In
summary,
the
msesmexlt
of
the
human'hedth
risk
posed
by
global
climate
change
thus
presents
a
new
challenge
to
public
health
professionals.
A
framework
for
ecologically­
based
human
health
risk
assessment
will
need
to
be
developed,
since
conventional
dose­
response
risk
assessments
may
not
apply
to
climate
change
health
research.
Studies
should
include
historical
analysis
of
climate
and
geographical
discase
data
in
cambination
with
simulation
studies
utilizing
inregrated
mathematical
models.

k
v
s
k
of
Prevention:
the
Public
Henlth
Model
In
addition
to
mrnmending
further
research,
monitoring
and
education
in
addressing
this
long­
term
health
threat,
we
must
begin
to
consider
implementation
of
preventive
options.
Conventid
preventive
strategies
in
public
health
are
classifie&
s
either
primary,
secondary,
or
tertiary
in
relation
to
the
point
along
the
causal
pathway
to
disea~
a
Primary
prevention
refers
to
avoidance
or
removal
of
a
hazardous
expure
or
otecting
individuals
SO
that
exposure
to
the
hazard
is
of
no
consequence.
Examples
could
inch
r
e
venting
of
noxious
fumes
in
an
occupational
setting
a
administering
childhad
vaccinations,
rwpectively.
Swxlndary
prevention,
somewhat
'

'downstream"
in
the
disease
pathway,
involves
early
detection
(or
screening)
of
an
altered
human
physiologic
state
and
subsequent
intervention
which
averts
full
progression
to
disease,
e.
g.,
a
mammogram
for
breast
cancer
screening.
This
also
appliea
to
population­
wide
screening
for
the
­
first
"index
case"
of
a
disease
which
would
dert
health
officials
to
bolster
preventive
rneasm
to
avoid
subsequent
cases,
Finally,
tertiary
pevention,
which
in
practical
'terms
is
trearment
rather
than
prevention,
attempts
to
minimize
the
advetse
effccts
of
the
already
present
disease.
The
further
"upstream"
an
intervention
can
be
impl'emented,
generally,
the
greaterthe
potential
health
benefit
to
the
largest
number
of
individuals.
Likewise,
the
further
upstream
the
pvention,
the
lower
the
per­
case
cost.

Preventive
measures
should
neither
exwrbate
the
primary
hazardous
exposure,
nor
should
they
introduce
new
hazards
themselves.
In
esserx=
e,
the
"cure"
must
not
be
wow
than
tk
"disease".
Some
options
to
protect
populations
are
energy
intensive,
e.
g.,
air
conditioning,
that
will
worsen
greenhouse
warming
via
increasing
demand
for
energy
unless
alternative
energy
80urces
are
developed.
Vector­
control
i
s
another
response
wit5
potentially
h
d
u
l
side
effecb
as
mentioned
above.
In
essence,
we
must
avoid
solving
om
environmental
health
problem
by
compounding
another.

Finally,
policies
to
address
climate
change
will
be
expected
to
have
short­
and
long­
tern
benefits,
and
both
must
be
considered
in
planning
optimal
preventive
strategiw
Health
gains
realized
through
the
reduction
in
air
pollution
stemming
from
greedmuse
gas
reduction,
for
example,
could
substantial.
Such
short­
term
gains
must
weigh
into
any
policy
decision,
considering
the
inherent
uncertainties
of
predicting
long­
term
hazardous
expasures
due
to
climate
change.
As
with
most
of
the
health
outcomes
described
abve,
impacts
from
climate
change
should
not
be
viewed
in
isolation
fmm
other
determinants
of
health.
This
case
of
air
pollutiw
reduction
"companying
p
s
i
ble
climate
change
policy
clearly
illustrates
the
need
to
integrate
this
issue
with
o
t
h
e
r
environmental
health
problems
­
in
this
case,
air
pollution
and
climate
change,
rpYicy
go
hmd
irr
L
n
m
A
CON@
LU$
ION
In
the
history
of
public
health
and
medicine,
our
specialized
appmh
to
research
(and
prevention)
has
to
this
point
been
quite
mccewfd
in
identifying
single
etiologic
agents,
including
micrwrganisme,
chemical
toxins,
and
sjxcific
harmful
human
behaviors.
The
Mth
effects
R­
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#2
2
In
dealing
with
these
6ompIex%
sUes,
we
will
be
faced
with
making
policy
decisions,
within
a
setting
of
inevitable
uncertainty.
Furthermore,
efforts
to
duce
the
uncertainty
of
health
risk
assessment
of
climate
change
will
require
improved
disease
surveiUance
and
concerted
efforts
among
scientists
to
achieve
fully
integrated
assessments.
The
large
inertia
of
the
dimate
system,
requires
adaptive
options
to
be
p
c
t
i
v
c
to
reduce
potentially
large
disease
burdens.

Considering
the
magnitude
and
long­
term
nature
of
the
tial
pblic
health
impacts
from
climate
change,
a
rational
approach
would
stress
continued
stu
8"""
y
and
monitoring,
accornahting
a
range
of
possible
health
outcomes.
Similariy,
preventive
policies
should
emphasize
measures
that
are
appropriate
for
current
conditions
and
build
capacity
to
respond
to
both
expected
and
unexpected
threats
to
human
health.
Interdisciplinary
links
fw
promoting
an
integrated
assessment
must
be
advocated
to
reduce
these
uncertainties.
Yet,
fora
public
healthchallenge
as
complex
and
potentially
l
a
r
g
e
(and
possibly
ineversible)
as
globat
climate
change,
discussion
must
not
only
occur
between
health
pfessiaals
and
scientists
from
diverse
fields,
but
must
extend
include
policy
makers
at
all
levels
of
the
assessment.
In
an
area
with
much
uncertainty,
such
cooperatian
will
ultimately
enhance
the
risk
communication
nece~~
ary
for
making
informed
decisions
affecting
the
health
of
the
public.
­

ACKNOWLEDGMENTS
Special
thanks
to
the
primary
reveiwers
for
this
pap.
Professor
Anthony
J.
McMichael,
Departmat
d
Epidemiology
and
Population
Sciences,
London
School
of
Hygiene
and
Tropical
Medicine,
and
Professor
Jonathan
Samet,
Chairman,
D
e
m
e
n
t
of
Epidemiology,
Jdhns
Hopkins
Schod
of
Hygiene
and
Public
HeaIth.

M
a
l
funding
supprt
for
some
ofthe
healWctimate
assessments
cited
in
this
paper
has
been
provided
by
the
Climate
Policy
and
Assessment
Division
of
the
US
EPA,
Cooperative
Agrement
#
CR823
143010.
For
valuable
comments
I
thank
Professor
Andrew
b
i
n
e
s
,
University
College
London
Medid
School
and
Dr.
Rudi
Sloaff,
World
Health
Organization.

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PAGE
82
Palr
16
4109551811
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26PM
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#24
R­
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17
4
1
0
9
5
5
1
6
1
1
06­
10­
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02:
26PM
P
O
0
3
#2
4
18
R=
98%
4
1
0
9
5
5
1
8
1
1
0
6
­1
0
­9
6
0
2
:
26Pl.
f
PO04
S24
19
4
1
0
9
5
5
1
8
1
1
0
6
­1
0
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26PM
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#2
4
/

R­
98%
20
4
1
0
9
5
5
1
8
1
1
06­
10­
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02:
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PO06
#24
.
­
.
."
..
Figure
1
I
URBAN
HEAT
Heat­
related
ISLAND
EFFECT
Respiratory
dims
Dengue
€4
DHF
Encephalitis
Malaria
Lyme
disease
Yellow
fever
Toxic
algae
&
cholera
­

Malnutrition
&
immunosuppres­
sion
se
Diarrheal
&
vector­

Lost
public
health
infrastructure
DISASTERS
5
bme.
diseases,
&

Overcrowding,
poor
disease
&
impacts
on
fisheries
SEA
LEVEL
sanitation,
infectious
OZONE
DEPLrnON
Skin
Cancers
imrnuno­
suppression
UV­
8
Radiation
­­­­
Ocular
cataracts
Anficlgated
causal
pathways
of
public
health
impacts
from
climate
change.
Adapted
from:
Patz
&
Balbus.
Methods
for
assessing
public
health
vulnerability
to
climate
change.
Climate
Research
1996;
6:
1
13­
1
25.

R­
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4
1
0
9
5
5
1
8
1
1
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02:
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PO07
#24
Leishmaniasis
Onchcroeniasis
(River
Blindness)

Ycllaw
Fever
9
173
miUian
Tropi­
ics
Tropialhfrica
Africahatn
Amcrica
Ccntnl
and
SoUthAmtrica
c
R­
97%
4109551811
06­
10­
96
02:
26PM
PO08
#2
4
Figure
2
r­

4
1
0
9
5
5
1
8
1
1
.
...
..
OE­
10­
96
0
2
:
26PM
PO09
#24
.
A
.

TESTIMONY
OF
GARY
S.
GUZY
GENERAL
COUNSEL
U.
S.
ENVIRONMENTAL
PROTECTION
AGENCY
SUBCOMMITTEE
GN
NATiONAL
ECONOMIC
GROWTH,
NATURAL
RESOURCES'AND
REGULATORY
AFFAIRS
OF
THE
COMMITTEE
ON
GOVERNMENT
REFORM
AND
THE
SUBCOMMITTEE
ON
ENERGY
AND
ENVIRONMENT
OF
THE
COMMITTEE
ON
SCIENCE
U.
S.
HOUSEQF
REPRESENTATIVES
,/

­
.
BEFORE
A
JOINT
HEARING
OF
THE
October
6,1999
Thank
you,
Chairman
McIntosh,
Chairman
Calvert,
and
Members
of
the
Subcommittees,
for
the
invitation
to
appear
here
today.
I
am
pleased
to
have
this
­

opportunity
to
explain
the
U.
S.
Envifonmental
Protection
Agency's
(EPA)
views
as
to
the
legal
authority
provided
by
the­
klean
Air
Act
(Act)
to
regulate
emissions
of
carbon
dioxide,
or
CO,.

Before
I
do,
however,
1
would
like
to
stress,
as
EPA
repeatedly
has
stated
in
letters
to
Chairman­
McIntosh
and
other
Members.
of
Congress,
that
the
Administration
has
no
intention
of
imple­
irmting
the
Kyoto
Protocol
to
the
United
Nations
Framework
Convention
on
CIimte
Change
prior
to
its
ratification
with
the
advice
and
consent
of
the
Senate.
'
As
I
indicated
in
my
letter
of
September
17,
1999
to
Chairman
McIntosh,

'
S
e
e
,
e.
g.,
Letter
f
r
m
Gz­
y
S.
C
L
'
Z
~,
Gcnerel
Counse!,
to
Consressman
~a!;
id
McIntosh,
September
17,
1999;
Letter
from
David
Gardiner,
Assistant
Administrator
for
Policy,
to
Congressman
David
McIntosh,
June
23,
1999;
Letter
from
David
Gardiner,
Assistant
Administrator
for
Policy,
to
Congressman
David
Mclntosh,
August
13,
1988.

Plaintiff
Exhibit
No.
..
....
.....
..
...
...
...
..
..
............
..
....
....
­
i
._
,­
.
...
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..
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.

....
....
..

..
..

...
.......
.;
_.
_.
i
.
~

.

............
...
......
.....
...
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._

......
.
.~
.

...
.
.i
,
...............
...................
...
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"

......
.......
.
"
.....
...
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:.
.
.
­
..".
:.:
.::.:

...;:;,
~
.:.
:
..
........
.....
..
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........
...
..
....
,

there
is
a
clear
differL.,
ce
between
actions
that
carry
out
a.
.rarity
under
the
Clean
Air
Act
or
other
domestic
law,
and
actions
that
would
implement
the
Protocol.
Thus,
there
is
nothing
inconsistent
in
assessing
the
extent
of
current
authority
under
the
Clean
Air
*
*
­

Act
and
maintaining
our
commitment
not
to
implement
the
Protocol
without
ratification:

Some
brief
background
information
is
helpful
in
understanding
the
context
for
this
question
of
legal
authority.
In
the
course
of
generating
electricity
by
burning
fossil
fuels,
electric
power
plants
emit
into
the
air
multiple
substances
that
pose
environmental
concerns,
several
of
which
.are
already
subject
to
some
degree
of
regulation.
Both
industry
and
government
share
an
interest
in
understanding
how
d
different
pollution
control
strategies
interact.
These
interactions
are
both
physical
(strategies
for
controlling
emissions
of
one
substance
can
affect
emissions
of
others)

and
economic
(strategies
designed
to
address
two
or
more
substances
together
can
cost
substantially
less
than
strategies
for
individual
pollutants
that
are
designed
and
­

i'

implemented
independently).
EPA
has
worked
with
a
broad
array
of
stakeholders
to
evaluate
multiple­
pollutant
control
stra.
tegies
for
this
industy
in
a
series
of
forums,

dating
back
to
the
Clean
Air
Power
initiative
(CAPI)
in
the
mid­
1990s.
While
the
CAP1
process
focused
on
SO2
and
NOx,
a
broad
range
of
participants,
including
representatives
of
power
generators,
the
United
Mine
Workers,
and
environmentalists,

expressed
support
for
inclusion
of
CO2'emissions;
aiong
with
S02,
NOx,
and
mercury,

in
subsequent
analyses.
One
conclusion
that
emerged
from
these
analytical
efforts
is
that
integrated
strategies
using
market­
based
"cap­
and­
trade"
approaches
like
the
2
>
,/
'
i
.
,.".
,
­
program
currently
in
,.
ace
to
address
acidrain
would
be
t
i
.
most
flexible
and
lowest
cost
means
to
control
multiple
pollutants
from
these
sources.

6
6
OnM5rch
1
I,
1998,
during
hearings
on
EPA's
FY
1999
appropriations;

Representative
CeLay
asked
thz
Administrator
whether
she
believed
that
EPA
had
.

authority
to
regulate
emissions
of
pollutants
of
concern
from
electric
utilities,
including
CO,.
She
replied
that
the
Clean
Air
Act
provides
such
authority,
and
agreed
to
Representative
DeLay's
request
for
a
legal
opinion
on
this
point.

Therefore,
my
predecessor,
Jonathan
Z.
Cannon,
prepared
a
legal
opinion
for
EPA
Administrator
Carol
Browner
on
tfe
question
of
EPA'S
legal
authority
to
regulate
several
pollutants,
including
CO,
emitted
by
electric
power
generation
sources.
The
legal
opinion
requested
by
Rep.
Delay
was
completed
on
April
I
O
,
1998.
It
addressed
the
Clean
Air
Act
authority
to
regulate
emissions
of
four
pollutants
of
concern
from
.

electric
power
generation:
nitrogen
dxides
(NO,,,
sulfur
dioxide
(SO,),
mercury,
and
.

C
O
,
Because
today's
hearing
is
focused
exclusively
on
CO,,
1
will
summarize
the
­

opinion's
conclusions
only
as
they
relate
to
that
substance.

The
Clean
Air
Act
includes
a
definition
of
the
term
"air
pollutant,
''
which
is
the
touchstone
of
EPA's
regulatory
authority
over
emissions.
Section
302(
g)
defines
"air
pollutant"
as
,.

any
air
pollution
agent
or
Combination
ofsuch
agents,
including
any
physical,
chemical,
biological,
[or]
radioactive
.
.
.
substance
or
matter
which
is
emitted
into
or
otherwise
enters
the
ambient
air.
Such
term
includes
any
precursors
to
the
.
'

formation
of
any
air
pollutant,
to
the
extent
that
the
Administrator
has
identified
such
precursor
or
precursors
for
the
particular
purpose
for
which
the
term
"air
pollutant"
is
used,

Mr.
Cannon
noted
that
CO,
is
a
"physical
[and]
chemical
substance
which
is
emitted
3
­
..
:.
.
..
..
.
­
.
..
­.
.
..
..
­
into
...
the
ambient
all
,
'
and
t
h
u
s
is
an
"air
pollutant''
withi,.
.ne
Clean
Air
Act's
(.

definition.
Congress
explicitly
recognized
emissions
of
CO,
from
stationary
sources,

such
as
fossiifuel
power
plants,
as
an
"air
pollutant"
in
Section
103(
g)
of
the
Act,
which
4
4
authorizes
EPA
to
cocduct
a
basis
research
and
technology
program
to
include,
among
other
things,
"[
i]
mprovements
in
nonregulatory
strategies
and
technologies
for
preventing
or
reducing
multiple
air
pollutants,
includinq
sulfur
oxides,
nitrogen
oxides,

heavy
metals,
PM­
10
(particulate
matter),
carbon
monoxide,
and
carbon
dioxide,
from
stationary
sources,
including
fossil
fuel
power
plants."
(Emphasis
added.)
4
The
opinion
explains'further
that
the
status
of
CO,
as
an
"air
pollutant"
is
not
changed
by
the
fact
that
C02
is
a
constituent
of
the
natural
atmosphere.
In
other
words,

a
substance
can
be
an
"air
pollutant"
under
the
Clean
Air
Act's
definition
even
if
it
has
natural
sources
in
addition
to
its
man­
made
sources.
EPA
regulates
a
number
of
­

~.
.....
..
..
.­
..
i
."
,.
­
..
­..
naturally­
occurring
substances
as
ai;
pollutants
because
human
activities
have
.
.

increased
the
quantities
present
in
the
air
to
levels
that
are
harmful
to
public
health,

welfare,
or
the
environment.
For
example,
SO,
is
emitted
from
geothermal
sources;

volatile
organic
compounds.
(VOCs),
which
are
precursors
to
harmful
ground­
level
ozone,
are
emitted
by
vegetation.
Some
substances
regulated
under
the
Act
as
hazardous
airpollutants
are.
actually
necessary
in
trace
quantities
forhuman
life,
but
are
tokk
at
higher
levels
orthrough
otherroutes
of
exposure.
Manganese­
and
i­:".
.i_
..
`

selenium
are
two
examples
of
such
pollutants.
Similarly,
in
the
water
context,

phosphorus
is
regulated
as
a
pollutant
because
although
it
is
a
critical
nutrient
for
plznts,
in
excessive
quantities
it
kills
aqugtic
life
in
lakes
and
other
water
bodies.
..

4
~.
..............
..
,...
........
......
......
L.
............
..
_:.
­.
.
:
..:
­.
.
..
......
­.
.
..
......
..
.
.+,­
x..
.­
i
While
CO,,
a,
A
n
"air
pollutant,"
is
within
the
sc0pL
~f
the
regulatory
authority
provided
by
the
Clean
Air
Act,
this
by
itself
does
not
lead
to
regulation.
The
Clean
Air
Act
includes3
number
of
regulatory
provisions
that
may
potentially
be
applied
to
an
air
a
pollutant.
But
before
EPA
can
actt~
ally
iswe
restilations
governing
a
polhtant,
the
Administrator
must
first
make
a
formal
finding
that
the
pollutant
in
question
meets
specific
criteria
laid
out
in
the
Act
as
prerequisites
for
EPA
regulation
under
its
various
provisions.
Manyof
these
specific
Clean
Air
Act
provisions
for
EPA
action
share
a
common
feature
in
that
the
exercise
of
EPA's
authority
to
regulate
air
pollutants
is
linked
to
a
determination
by
the
Administrator
regarding
the
air
pollutant's
actual
or
9
potential
harmful
effects
on
public
health,
welfare
or
the
environment.
For
example,

EPA
has
authority
under
section
109
of
the
Act
to
establish
National
Ambient
Air
Quality
Standards
for
any
air
pollutant
for
which
the
Administrator
has
established
air
quality
criteria
under
section
108.
U$
der
section
108,
the
Administrator
must
first
find
­

that
the
air
pollutant
in
question
meets
several
criteria,
including
that:

­
it
causes
orcontributesto"
airpollutionwhichmay
reasonably
be
anticipated
to
endanger
public
health
or
welfare;"
and
­
its
presence
in
the
ambientair'"
resu1tsfromnumerous
or
diverse
mobile
or
stationary
sources
...
.'I
Section
302(
h),
a
provision
dating
back
to
the
1970
version
of
the
Clean
Air
Act,
defines
"welfare"
and
states:

all
language
referring
to
effects
on
welfare
includes,
but
is
not
limited
to,
effects
on
soils,
water,
crops,
vegetation,
man­
made
materials,
animals,
wildlife,
weather,
visibility,
and
climate,
damage
to
and
deterioration
of
property,
and
hazards
io
transpofiation,
2s
L
V
~
as
&ki=
ts
on
econcnic
va!
ves
and
on
person?!
comfort
and
well­
beim!
whether
caused
by
transformation.,
conversion,
or
combination
with
other
air
pollutants.

5
......
.....
.......
..
.....
..
.....
,

­.
#­,
/

Thus,
since
1970,
t
h
t
Jean
Act
has
included
effects
on
considered
in
the
Administrator's
decision
as
to
whether
section
108.­
*
,/

r­"..
,

"c,.
.late"
as
a
factor
to
be
to
list
an
air
pollutant
under
Analogous
threshold
findings
sre
required
before
the
Administrator
may
establish
new
source
performance
standards
for
a
pollutant
under
section
11
1,
list
and
regulate
the
pollutant
as
a
hazardous
air
pollutant
under
section
112,
or
regulate
its
emission
from
motor
vehicles
under
Title
I
I
of
the
Act.

Given
the
clarity
of
the
statutory
provisions
defining
"air
pollutant"
and
providing
'4
authority
to
regulate
air
pollutants,
there
is
no
statutory
ambiguity
that
could
be
clarified
by
referring
to
the
legislative
history.
Nevertheless,
I
would
note
that
Congress'

decision
in
the
1990
Amendments
not
to
adopt
additional
provisions
directing
EPA
to
regulate
greenhouse
gases
by
no
means
suggests
that
Congress
intended
to
limit
a­

existing
authority
to
address
any
aicpollutant
that
the
Administrator
determines
meets
the
statutory
criteria
for
regulation
under
a.
specific
provision
of
the
Act.

I
would
like
today
to
reiterate
one
of4he
central
conclusions
of
the
Cannon
memorandum,
which
stated:
"While
CO,,
as
an
air
pollutant,
is
within
EPA's
scope
of
authority
to
regulate,
the
Administrator
has
not
yet
determined
that
CO,
meets
the
criteria
for
regulation
.under
one
or
more
provisions
of
the
Act."
That
statement
remains
true
today.
EPA
has
not
made
any
of
the.
Aet's
threshold
findings
that
would
lead
to
regulation
of
CO,
emissions
from
electric
utilities
or,
indeed,
from
any
source.
The
opinion
of
my
predecessor
simply
clarifies
­­
and
I
endorse
this
opinion
­­
that
CO,
is
in
the
class
of
compounds
that
coulcl
be
subject
to
several
of
the
Fiean
Air
A&
s
....

regulatory
approaches.
Thus,
I
would
suggest
that
many
of
the
concerns
raised
about
6
..
....
...
.....
...
__
....
­.
..
..

...
.­
...
......
....
...
..

"
..
.......
..
....
..
..........
..
.­

t
h
e
statutory
authority
[o
address
CO,
relate
more
to
factuGl
and
scientific,
rather
than
legal,
questions
regarding
whether
and
how
the
criteria
for
regulation
under
the
Clean
a
*
Air
Act
could
be
satisfied.

1
also
want
to
notq
however,
EPA
has
strongly
promoted
voluntary
partnerships
to
reduce
emissions
of
greenhouse
gases
through
the
EnergyStar
and
Green
Lights
programs
and
other
non­
regulatory
programs
that
Congress
has
consistently
supported.

These
successful
programs
already
have
over
7,000
voluntary
partners
who
are
taking
steps
to
reduce
greenhouse
gas
emissions,
reduce
energy
costs
and
help
address
local
air
pollution
problems.
These
programs
also
help
the
United
States
meet
its
3
obligations
under
the
United
Nations
Framework
Convention
on
Climate
Change,
which
was
ratified
in
1992.
I
would
also
note,
as
EPA
has
indicated
in
past
correspondence
with
Chairman
McIntosh
and
others,
in
the
course
of
carrying
out
the
mandates
of
the
Clean
Air
Act,
EPA
has
in
a
few
insiances
directly
limited
use
or
emissions
of
certain
­

greenhouse
gases
other
than
CO,.
.For
example,
EPA
has
limited
the
use
of
certain
substitutes
for
ozone­
depleting
substances
under
Title
VI
of
the
Act,
where
those
substitutes
have
very
high
global
warming
potentials.
i
wish
to
stress
once
more,

however,
that
while­
EPA
will
pursue
efforts
to
address
the
threat
of
global
warming
through
the
voluntary
programs
authorized
and
funded
by
Congress
and
will
carry
out
the
mandates
of
the
Clean
Air
Act,
this
Administration
has
no
intention
of
implementing
the
Kyoto
Protocol
prior
to
its
ratification
on
the
advice
and
consent
of
the
Senate,

This
concludes
my
prepared
sistment.
I
would
be
happy
to
mswer
any
questions
that
you
may
have.

7
APR
I
0
1
9
5
8
MEMORANDUM
1.
Xntmduction
and
Background
c,
I,.

A
Definition
of
Air
PoHutant
my
air
pollution
agent
or
combination
of
such
agents,
including
any
physical,
chcrnical,
bjologd,
[or3
radioactive
­
.
.
substance
or
matter
which
is
crnittcd
into
or
othwisc
emers
the
ambieht
air.
Such
tern
includcs
any
precursors
to
the
formation
of
any
air
pohtanr,
to
the
e
x
t
e
n
t
that
thc
Administtaror
has
idemifiicd
such
precursor
or
prtcursors
for
the
particular
purpose
for
which
the
term
"air
pollutant"
i
s
used.

This
broad
definition
states
that
"air
pollutant"
includes
any
physical,
chemic&
biologjtaj,
or
radioactive
substance
ctr
matter
that
is
emitted
into
or
otherwise
enters
the
ambient
air.
so,,
NO,,
CO,
and
mercury
from
ciectric
power
gcncration
Ere
each
a
"physical
[and]
chemicd
,
,
.

.
..
:

"
2
.
..
,
"

.
.
.,.
..
..
:
..
.
.
..
/­..

4
"

TOTRL
P.
06
