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CHANGE 4HE PROCESS USED TO PRODUCE
THESE ASSESSMENTS IS DESIGNED TO
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SCIENCE AND POLICY COMMUNITIES
#OMPREHENSIVE ASSESSMENTS WERE
PUBLISHED IN AND 4HREE SEPARATE hWORKING GROUPSv
EXAMINE THE PHYSICAL SCIENCE OF
CLIMATE CHANGE THE EFFECTS ON
NATURE AND SOCIETY AND METHODS FOR
MITIGATION
,EAD AUTHORS WHO ARE ACTIVE PARTICI
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%ACH OF THE THREE WORKING GROUPS
ALSO ISSUES A h3UMMARY FOR 0OLICY
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± -/2% 4/
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OF THE )0## STATED IN ITS *ANUARYn&EBRUARY
REPORT hVERY LIKELYv TO BE LARGELY THE
RESULT OF HUMAN ACTIVITIES FOR AT LEAST THE PAST
HALF A CENTURY "UT IS THAT WARMING SIGNIlCANT
ENOUGH TO POSE REAL PROBLEMS 4HAT
DETERMINATION FELL TO 7ORKING 'ROUP )) A
SIMILARLY INTERNATIONAL ASSEMBLY OF SCIENTISTS
WHO FOCUSED ON THE VULNERABILITY OF NATURAL
AND HUMAN ENVIRONMENTS TO CLIMATE CHANGE
)N THE !PRIL SUMMARY OF ITS lNDINGS
7ORKING 'ROUP )) CONCLUDED THAT HUMAN
INDUCED WARMING OVER THE PAST THREE AND A HALF
DECADES HAS INDEED HAD A DISCERNIBLE INmUENCE
ON MANY PHYSICAL AND BIOLOGICAL SYSTEMS
/BSERVATIONAL EVIDENCE FROM ALL CONTINENTS AND
MOST OCEANS SHOWS THAT MANY NATURAL SYSTEMS
ARE BEING AFFECTED BY REGIONAL CLIMATE CHANGES
PARTICULARLY TEMPERATURE INCREASES 4HE GROUND
IN PERMAFROST REGIONS IS BECOMING INCREASINGLY
UNSTABLE ROCK AVALANCHES IN MOUNTAINOUS
AREAS ARE MORE FREQUENT TREES ARE COMING INTO
LEAF EARLIER AND SOME ANIMALS AND PLANTS ARE
MOVING TO HIGHER LATITUDES OR ELEVATIONS
,OOKING TO THE FUTURE THE GROUP ALSO PRO
JECTED THAT ONGOING SHIFTS IN CLIMATE WOULD
AFFECT THE HEALTH AND WELFARE OF MILLIONS OF
PEOPLE AROUND THE WORLD 4HE SEVERITY OF THE
EFFECTS WOULD DEPEND ON PRECISELY HOW MUCH
WARMING OCCURRED !MONG THE MOST PROBABLE
CONSEQUENCES
-ORE FREQUENT HEAT WAVES DROUGHTS lRES
COASTAL mOODING AND STORMS WILL RAISE THE TOLL
OF DEATHS INJURIES AND RELATED DISEASES
N 3OME INFECTIOUS DISEASES SUCH AS MALARIA
WILL SPREAD TO NEW REGIONS
N (IGH CONCENTRATIONS OF GROUNDLEVEL OZONE
WILL EXACERBATE HEART AND RESPIRATORY
AILMENTS
N "Y THE S RISING SEA LEVELS WILL mOOD THE
HOMES AND PROPERTY OF MILLIONS OF PEOPLE
ESPECIALLY IN THE LARGE DELTAS OF !SIA AND
!FRICA AND ON SMALL ISLANDS
N
4HE HARM FROM THESE CHANGES WILL BE MOST
SEVERE FOR IMPOVERISHED COMMUNITIES 4HE POOR
ARE GENERALLY MORE DEPENDENT ON CLIMATESEN
SITIVE RESOURCES SUCH AS LOCAL WATER AND FOOD
AND BY DElNITION THEIR ADAPTIVE CAPACITIES ARE
ECONOMICALLY LIMITED
4HE EFFECTS OF GLOBAL WARMING WOULD NOT BE
UNIVERSALLY BAD PARTICULARLY FOR THE NEXT FEW
DECADES &OR EXAMPLE WHEREAS HIGHER TEMPERA
TURES WOULD HURT THE GROWTH OF IMPORTANT CEREALS
IN EQUATORIAL NATIONS FAIRLY QUICKLY THEY WOULD
FOR A TIME RAISE PRODUCTIVITY ON FARMS IN MID TO
HIGHLATITUDE COUNTRIES SUCH AS THE 53 "UT
ONCE THE TEMPERATURE INCREASE EXCEEDED THREE
DEGREES #ELSIUS DEGREES &AHRENHEIT AGRI
CULTURAL DECLINES WOULD SET IN EVEN THERE BARRING
WIDESPREAD ADAPTIVE CHANGES
#ENTRAL AND 3OUTH !MERICA
N
N
$!.)%,! .!/-) -/,.!2 OCR 3/52#% 5.)6%23)49 #/20/2!4)/. &/2 !4-/30(%2)# 2%3%!2#( 5#!2 !.$ )0##
7(!4 .%%$3 4/ "% $/.%
N
4HE HUMAN RACE CAN RESPOND TO CLIMATE CHANGE IN TWO WAYS ADAPTATION
AND MITIGATION !DAPTATION MEANS LEARNING HOW TO SURVIVE AND PROSPER
IN A WARMER WORLD -ITIGATION MEANS LIMITING THE EXTENT OF FUTURE
WARMING BY REDUCING THE NET RELEASE OF GREENHOUSE GASES TO THE
ATMOSPHERE 'IVEN THAT RISING TEMPERATURES ARE ALREADY ENCROACHING ON
US AND THAT AN UNSTOPPED INCREASE WOULD BE OVERWHELMING A STRONG
COMBINATION OF BOTH ADAPTATION AND MITIGATION WILL BE ESSENTIAL
5NFORTUNATELY DISAGREEMENTS OVER THE FEASIBILITY COSTS AND NECESSITY OF
MITIGATION HAVE NOTORIOUSLY BOGGED DOWN GLOBAL RESPONSES TO DATE
4O PROJECT MITIGATION STRATEGIES FOR THE LOOMING PROBLEMS ˆ AND THEIR
COSTS ˆ 7ORKING 'ROUP ))) OF THE )0## CONSIDERED VARIOUS ESTIMATES OF
ECONOMIC EXPANSION POPULATION GROWTH AND FOSSILFUEL USE FOR ITS REPORT 4HE SIX RESULTING SCENARIOS PREDICT ATMOSPHERIC CONCENTRATIONS OF
CARBON DIOXIDE EQUIVALENTS THAT IS GREENHOUSE GASES AND AEROSOLS EQUIV
ALENT TO CARBON DIOXIDE RANGING FROM PARTS PER MILLION TO PPM
WITH CORRESPONDING INCREASES IN TEMPERATURES FROM TO AS MUCH AS DEGREES # APPROXIMATELY TO DEGREES & OVER PREINDUSTRIAL LEVELS
4O KEEP THE TEMPERATURE INCREASE TO THE LOWEST OF THOSE PROJECTIONS THE
GROUP ESTIMATES THAT THE WORLD MUST STABILIZE ATMOSPHERIC GREENHOUSE
GASES AT PPM BY #URRENT CONCENTRATIONS ARE APPROACHING PPM 4HE SCIENTISTS BELIEVE THAT ANY HIGHER TEMPERATURES MIGHT TRIGGER
,' 3 # ) % . 4 ) & ) # ! - % 2 ) # ! .
'RADUAL REPLACEMENT OF TROPICAL FOREST
BY SAVANNA IN EASTERN !MAZONIA
2EPLACEMENT OF SEMIARID VEGETATION
BY ARIDLAND VEGETATION
3PECIES EXTINCTIONS IN MANY
TROPICAL AREAS
SEVERE mOODING IN
N 2EDUCED WATER AVAILABILITY
SOME PLACES AND SEVERE
N ,OSS OF ARABLE LAND IN DRIER AREAS
DROUGHT IN OTHERS WIPE
OUT SPECIES AND CAUSE
N $ECREASED YIELDS OF SOME
ECONOMIC HAVOC
IMPORTANT CROPS
4HE GROUPS REPORT
N 2EDUCED LIVESTOCK PRODUCTIVITY
LOOKS IN DETAIL AT THE
MOST PROMISING TECH
NOLOGIES AND POLICIES FOR HOLDING THE GASES AT PPM )T EMPHASIZES
THE IMPORTANCE OF IMPROVING ENERGY EFlCIENCY IN BUILDINGS AND VEHICLES
SHIFTING TO RENEWABLE ENERGY SOURCES AND SAVING FORESTS AS hCARBON
SINKSv 0OLICIES INCLUDE SETTING A TARGET FOR GLOBAL EMISSIONS EMISSIONS
TRADING SCHEMES CAPS TAXES AND INCENTIVES
"UT THE )0## SCIENTISTS MADE THEIR ASSESSMENT BEFORE A STUDY PUB
LISHED ONLINE THIS PAST !PRIL IN THE 2TQEGGFKPIUQHVJG0CVKQPCN#ECFGO[
QH5EKGPEGU75#REPORTED THAT WORLDWIDE CARBON DIOXIDE EMISSIONS
BETWEEN AND INCREASED AT THREE TIMES THE RATE OF THE S ˆ
FROM TO PERCENT A YEAR )N OTHER WORDS THE ACTUAL GLOBAL EMIS
SIONS SINCE GREW FASTER THAN THOSE PROJECTED IN THE HIGHEST OF THE
SCENARIOS DEVELOPED BY THE )0## 4HAT RESEARCH INDICATES THAT THE SITUA
TION IS MORE DIRE THAN EVEN THE BLEAK )0## ASSESSMENT FORECASTS
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4HE LISTS HERE INDICATE JUST SOME OF THE DISTURBING EFFECTS BEYOND THOSE ENUMERATED IN
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THE COMING CENTURY 4HE GROUP MADE MOST OF THESE PREDICTIONS WITH HIGH OR VERY HIGH
CONlDENCE &IND MORE DETAILS AT WWWUCAREDUNEWSFEATURESCLIMATECHANGE
REGIONALIMPACTSJSP AND AT THE )0## 7EB SITE WWWIPCCCH
.ORTH !MERICA
N
%UROPE
N
N
N
)N THE WESTERN MOUNTAINS DECREASED SNOWPACK MORE
WINTER mOODING AND REDUCED SUMMER mOWS
N
N
N
N
!N EXTENDED PERIOD OF HIGH lRE RISK AND LARGE INCREASES
IN AREA BURNED
)NCREASED RISK OF INLAND mASH mOODS
)N THE SOUTH MORE HEALTHTHREATENING HEAT WAVES AND
WILDlRES REDUCED WATER AVAILABILITY AND HYDROPOWER
POTENTIAL ENDANGERED CROP PRODUCTION AND REDUCED
SUMMER TOURISM
)N THE CENTRAL AND EASTERN AREAS MORE HEALTHTHREATENING
HEAT WAVES AND PEATLAND lRES AND REDUCED SUMMER RAIN
FALL AND FOREST PRODUCTIVITY
)N THE NORTH NEGATIVE IMPACTS EVENTUALLY OUTWEIGH SUCH
INITIAL BENElTS AS REDUCED HEATING DEMAND AND INCREASED
CROP YIELDS AND FOREST GROWTH
)NCREASED INTENSITY DURATION AND NUMBER OF HEAT WAVES
IN CITIES HISTORICALLY PRONE TO THEM
)N COASTAL AREAS INCREASED STRESS ON PEOPLE AND PROPERTY
AS CLIMATE INTERACTS WITH DEVELOPMENT AND POLLUTION
!SIA
N
N
)NCREASED mOODING ROCK AVALANCH
ES AND WATER RESOURCE DISRUPTIONS
AS (IMALAYAN GLACIERS MELT
/NGOING RISK OF HUNGER IN SEVERAL
DEVELOPING REGIONS BECAUSE OF
CROP PRODUCTIVITY DECLINES COM
BINED WITH RAPID POPULATION
GROWTH AND URBANIZATION
!USTRALIA AND
.EW :EALAND
N
N
3MALL ISLANDS
N
N
N
N
N
4HREATS TO VITAL INFRASTRUCTURE
SETTLEMENTS AND FACILITIES BECAUSE
OF SEALEVEL RISE
2EDUCED WATER RESOURCES IN MANY PLACES
BY MIDCENTURY
"EACH EROSION CORAL BLEACHING AND OTHER
DETERIORATING COASTAL CONDITIONS LEADING
TO HARMED lSHERIES AND REDUCED VALUE AS
TOURIST DESTINATIONS
)NVASION BY NONNATIVE SPECIES ESPECIALLY
ON MID AND HIGHLATITUDE ISLANDS
W W W 3 C I ! M C O M
0OLAR REGIONS
N
N
N
4HINNING AND SHRINKING OF GLACIERS AND
ICE SHEETS
#HANGES IN THE EXTENT OF !RCTIC SEA ICE
AND PERMAFROST
&URTHER LOSS OF BIODIVER
SITY IN ECOLOGICALLY RICH
SITES BY )NCREASED STORM SEVERI
TY AND FREQUENCY IN
SEVERAL PLACES
!FRICA
N
N
$EEPER SEASONAL THAWING OF PERMAFROST
N
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MILLION TO MILLION PEOPLE
,OSS OF ARABLE LAND REDUCED GROWING
SEASONS AND REDUCED YIELDS IN SOME AREAS
$ECREASED lSH STOCKS IN LARGE LAKES
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