Greenhouse Effect Mechanisms Affecting the Greenhouse Evidence for Climate Change.
GJJ1999 THE GREENHOUSE EFFECT AND CLIMATE CHANGE
Transcript of GJJ1999 THE GREENHOUSE EFFECT AND CLIMATE CHANGE
THE GREENHOUSE EFFECT AND CLIMATE CHANGE
A briefing from the Hadley Centre
Version 1: April 1999
• the greenhouse effect and greenhouse gases
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• the greenhouse effect and greenhouse gases
• modelling climate change
• predictions of climate change
• sea level rise and ocean currents
• uncertainties
• the attribution of recent change
THE GREENHOUSE EFFECT
Visible energy from the sun passes through the glass and heats the ground
Infra-red heat energy from the ground is partly
reflected by the glass, and some is trapped inside the
greenhouse
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THE GREENHOUSE EFFECT
SUNSome solar radiation isreflected by the earth’s
surface and the atmosphere
Some of the infraredradiation is absorbedand re-emitted by thegreenhouse gases.
The effect of this is towarm the surface
and the loweratmosphere
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ATMOSPHERE
Solar radiationpasses through theclear atmosphere
EARTHMost solar radiation is absorbedby the surface, which warms
Infrared radiationis emitted from theEarth’s surface
THE LONDON, EDINBURGH AND DUBLIN
PHILOSOPHICAL MAGAZINEAND JOURNAL OF SCIENCE
[FIFTH SERIES APRIL 1896]
XXXI. On the Influence of Carbonic Acid in the Air upon the Temperatureof the Ground. By Prof. SVANTE ARRHENIUS*.
1. Introduction: Observations of Langley on Atmospherical Absorption.
A GREAT deal has been written on the influence of the absorption of the atmosphere upon the climate. Tyndall † in particular has pointed out the enormous importance of this
question. To him it was chiefly the diurnal and annual variations of temperature that were lessened by this circumstance. Another side of the question, that has long attracted the
attention of physicists, is this: Is the mean temperature of the ground in any way
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lessened by this circumstance. Another side of the question, that has long attracted the attention of physicists, is this: Is the mean temperature of the ground in any way influenced by the presence of heat-absorbing gases in the atmosphere? Fourier ‡
maintained that the atmosphere acts like the glass in a hot house, because it lets through the light rays of the sun but retains the dark rays from the ground. This idea was
elaborated by Pouillet §; and Langley was by some of his researches led to the view, that ‘the temperature of the earth under direct sunshine, even though our atmosphere were present as now, would probably fall to – 200 °C., if that atmosphere did not possess the
* Extract from a paper presented to the Royal Swedish Academy of Sciences,11th December 1895. Communicated by the Author.
† “Heat a mode of motion,” 2nd ed. p.405 (Lond.,1865).‡ Mem. de l’Ac. R. d. Sci. de l’Inst. de France, t. vii. 1827.
§ Compress rendus, t. vii. p41 (1838).
Phil. Mag. S. 5. Vol. 41. No. 251. April 1896 S
ATMOSPHERE5.51.5
22
NATURAL AND HUMAN-MADE CYCLE OF CARBON
Annual transfers in GtC natural and human-made
3
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OCEANLAND
90 9060 60
22
Source: IPCC
THE EFFECT OF AEROSOL ON CLIMATE
Solar radiationscattered back =cooling influenceon climate
Aerosol in the
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Sulphur dioxideemissions
Aerosol in theboundary layer
THE INDIRECT EFFECT OF AEROSOL
Somesunlightreflected
More sunlightreflected –
cooling effect
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Brighter clouds‘Normal clouds’
Relatively cleanlower atmosphere
Pollutedlower atmosphere
ATMOSPHERIC CONSTITUENTS sources, lifetimes
Carbon dioxide Fossil fuels, land use changes 100 yea rs
Methane Agriculture, natural gas 10 years
Nitrous oxide Combustion 150 years
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Chlorofluorocarbons Production 100 years
Ground-level ozone Transport, industry 3 months
Aerosol Power generation, transport 2 weeks
RISING GREENHOUSE GAS CONCENTRATIONS
Carbon dioxide: 33% rise Methane: 100% rise
Mauna LoaObservatory
Flasks
340
360
380
1400
1600
1800
conc
entr
atio
n/pp
m
Met
hane
con
cent
ratio
n/pp
b
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Source: IPCC
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Ice cores
Ice cores
1700 1800 1900 2000Year
1700 1800 1900 2000Year
260
280
300
320
340
600
800
1000
1200
1400
CO
2co
ncen
trat
ion/
ppm
Met
hane
con
cent
ratio
n/pp
b
CONCENTRATIONS OF CO2
conc
entr
atio
n (p
pm)
750
650
550Constant 1990
emissions
Best estimate(IS92a)
CO2 concentration dueto three emission scenarios
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CO
2co
ncen
trat
ion
(ppm
)
450
350
2501990 2010 2030 2050 2070 2090
Year
Pre-industrial
50% 1990emissions
Source: IPCC
GREENHOUSE WARMING POTENTIALof some greenhouse gases, 100 year horizon
carbon dioxide 1methane 21nitrous oxide 310
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Source: IPCC
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nitrous oxide 310CFC12 8 100HCFC22 1 500HFC134a 420sulphur hexafluoride 34 900
RELATIVE WARMING OF GREENHOUSE GASES current emissions, over next 100 years
Methane24%
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Source: IPCC
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Tropospheric ozone
not included
24%Carbondioxide
63%Nitrous
oxide 10%
Others3%
PREDICTING CLIMATE CHANGE
CONCENTRATIONSCO2, methane, etc.
HEATING EFFECT
Scenarios frompopulation, energy,economics models
Carbon cycle andchemistry models
EMISSIONS
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HEATING EFFECT‘Climate Forcing’.
IMPACTSFlooding, food supply, etc.
Gas properties
Coupled climatemodels
Impacts models
CLIMATE CHANGETemp, rain, sea-level, etc.
CONCENTRATIONSCO2, methane, etc.
HEATING EFFECT
Scenarios frompopulation, energy,economics models
Carbon cycle andchemistry models
Feedbacks
EMISSIONS
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PREDICTING CLIMATE CHANGE
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HEATING EFFECT‘Climate Forcing’.
IMPACTSFlooding, food supply, etc.
Gas properties
Coupled climatemodels
Impacts models
CLIMATE CHANGETemp, rain, sea-level, etc.
Feedbacks
THE CLIMATE SYSTEM
Clouds
Solar
Terrestrialradiation
Greenhouse gases and aerosol
ATMOSPHERE
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OCEAN
PrecipitationSea-ice
LAND
Ice- sheetssnow
Biomass
Solarradiation
Atmosphere Atmosphere Atmosphere Atmosphere Atmosphere A tmosphere
Land surfaceLand surfaceLand surfaceLand surfaceLand surface
Ocean & sea-ice Ocean & sea-ice Ocean & sea-ice Ocean & sea-ice
Sulphateaerosol
Sulphateaerosol
Sulphateaerosol
Non-sulphateaerosol
Non-sulphateaerosol
Carbon cycle Carbon cycle
1975 1985 1992 1997
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HADLEY CENTRE EARTH SYSTEM MODEL
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Atmosphericchemistry
Ocean & sea-icemodel
Sulphurcycle model
Non-sulphateaerosols
Carboncycle model
Land carboncycle model
Ocean carboncycle model
Atmosphericchemistry
Atmosphericchemistry
Off-linemodeldevelopment
Strengthening coloursdenote improvementsin models
HADLEY CENTRECoupled Ocean Atmosphere Climate Model
• ocean model: 1.25°x 1.25°grid • 20 vertical levels: T, S
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• atmosphere model • 2.5°lat x 3.75°long•19 vertical levels•T, q, q c, v, p*
HADLEY CENTRE CLIMATE MODELFORTRAN programme code
CALL SUBROUTINE LSP_FOCWWIL! Purpose: Calculate from temperature the Fraction Of Cloud Water Which! Is Liquid. Operates within range 0 to -9 deg.C based upon! MRF observational analysis.
*CALL C_0_DG_CREAL& TSTART ! Temperature at which ROCWWIL reaches 1.&,TRANGE ! Temperature range over which 0 < ROCWWIL < 1.PARAMETER(TSTART=TM, TRANGE=9.0)DO I = 1, POINTS
TFOC = T(I)
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TFOC = T(I)! Calculate fraction cloud water which is liquid (FL)as in eq. P26.50.
IF (TFOC .LE. (TSTART - TRANGE)) THEN! Low temperatures, cloud water all frozen------------------------
ROCWWIL(I) = 0.0ELSE IF (TFOC .LT. TSTART) THEN
! Intermediate temperatures---------------------------------------ROCWWIL(I) = (TFOC - TSTART + TRANGE) / TRANGE
ELSE! High temperatures, cloud water all liquid-----------------------
ROCWWIL(I) = 1.0END IF
END DO ! Loop over points RETURNEND
*ENDIF
The third Hadley Centrecoupled climate model
• ocean resolution 1.25 o x 1.25o, plus improved ocean parametrisations
• improved parametrisation of radiation,
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• improved parametrisation of radiation, land surface, mountains, clouds
• obviates the need for flux corrections
• interactive sulphur cycle model
• better validation against ocean data
70°N
60°N
50°N
40°N
30°N
90°W 10°E10°W30°W50°W70°W
0 4 8 12 16 20
SIMULATION OF
THE GULF
STREAM
improves
at higher ocean
resolution
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70°N
60°N
50°N
40°N
30°N
90°W 10°E10°W30°W50°W70°W
Above: Currents at 50m
with 1.25 x 1.25°ocean
(HadCM3)
Below: Currents at 50m
with 2.5 x 3.75°ocean
(HadCM3L)
resolution
IMPACTS OF CLIMATE CHANGEassessments using Hadley Centre scenarios
• Hadley model data is supplied freely for impacts assessments, via the LINK/DDC project at UEA
• Data have been used by over 100 groups worldwide, for assessments including:
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for assessments including:
– African climate change (World Bank)
– Forest fires (WWF, USDA)
– Global water scarcity (ODA - DfID)
• Scenarios based on Hadley data used by national impacts assessments: UKCIP, US Programme, EC
GLOBAL TEMPERATURE RISEdue to “business-as-usual” greenhouse gas emissions
Tem
pera
ture
ris
e / d
egre
es C
Had
CM
3 G
HG
and
con
trol
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Tem
pera
ture
ris
e / d
egre
es C
Had
CM
3 G
HG
and
con
trol
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Changes in land, sea, and global mean surface tempe raturedue to ‘business-as-usual’ greenhouse gas emissions .
HadC
M3 G
HG
CHANGE in TEMPERATUREby the 2050s, relative to present day, northern win ter
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90N
0
45N
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Degrees C
Had
CM
3GH
G
90S
0
45S
180 18090W 90E0
-2 0 1 2 4 6 8
CHANGE in PRECIPITATIONby the 2050s, relative to present day, northern win ter
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90N
0
45N
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Mm/day
Had
CM
3GH
G
90S
0
45S
180 18090W 90E0
-4 42-2 0
CHANGES IN UK CLIMATE by the 2050srelative to the present day
0
20
10
5
2
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Annual meantemperature change (deg C)
Summertime (JJA)rainfall change (%)
-2
-5
-10
-20
HadCM2GHGx4UEANORWICH
Rel
ativ
e fr
eque
ncy
of o
ccur
renc
e
DAILY NIGHT MINIMUM TEMPERATURES
HadCM2 GHGSE England
Summer (JJA)
control
2070-99
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Rel
ativ
e fr
eque
ncy
of o
ccur
renc
e
Temperature / degree C
UK RAINFALL PROBABILITYPre-industrial 2050s
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Summer Winter
Pro
babi
lity
(%)
Pro
babi
lity
(%)
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Daily rainfall (mm) Daily rainfall (mm)
Pro
babi
lity
(%)
Pro
babi
lity
(%)
CHANGE IN UK WINTER PRECIPITATIONfrom the Global Model and the Regional Model
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GLOBAL MODEL EUROPEAN MODELmm/day
-1 0.5 0.2 0 0.5 1 1.5 -1 0.5 0.2 0 0.5 1 1.5
TEMPERATURE
RISE OVER
NORTHERN
ENGLANDWinter (DJF)
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6
4
2
0
-2
-4
-6
6
Tem
pera
ture
(oC
)
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Simulated by the
Hadley Centre
climate model,
relative to 1961-90H
adC
M3G
HG
Summer (JJA)
4
2
0
-2
-4
-6
Tem
pera
ture
(oC
)
1900 1950 2000 2050 2100Year
PREDICTIONS OF TEMPERATURE CHANGE
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HadC
M3
CHANGE IN SUMMER
RAINFALL OVER EUROPE
2030-2049(mm/day)
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top: when greenhouse gases only are increased
bottom: when the effect of changes in sulphate aerosol are also included
SEA LEVEL RISE and its components
0.8
0.6
0.4
TotalThermal expansionGlaciersGreenland
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HadC
M2 G
HG
1
0.4
0.2
0.01950 2000 2050 2100Year 1900
Sea-level rise 1860 –2100
PATTERNS OF SEA LEVEL RISEchange by 2090 from present day (mm)
90°N
45°N
0°
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HadC
M2 G
HG
1
45°S
90°S180 90°W 0 90°E 180
100 200 300 400 500 600 700Mean = 520 mm
CHANGE IN STORM SURGE FREQUENCY
Ret
urn
heig
ht/m
etre
s
Harwich (data from POL)
Current 100-yearreturn period water level
31 cm sea-level rise by 2050s
5.5
6.0
6.5
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Ret
urn
heig
ht/m
etre
s
by 2050s
Return periodin 2050s=20 years
1 10 100 10004.5
5.0
Return period/years
TEMPERATURE PROFILE IN THE OCEANchange by 2080s from pre-industrial
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HadC
M3 G
HG
SEA LEVEL RISE COMMITTMENTThermal expansion and land ice melt after an initial 1% increase in CO2 for 70 years
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GLOBAL OCEAN CIRCULATIONCOOLING
WARM
SURFACE
CURRENT
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INTERMEDIATE
WATERS
WARM AND LESS SALINE ANTARCTIC CIRCUMPOLAR CURRENT
CHANGES TO OCEAN CIRCULATION
UnperturbedIPCC ‘business-as-usual’2% pa rise in concentrations
–30
–25
–20
Circ
ulat
ion
stre
ngth
(S
verd
rups
)
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HadC
M3 G
HG
–20
–15
–101900 1950 2000 2050 2100
Year
Circ
ulat
ion
stre
ngth
(S
verd
rups
)
N ATLANTIC SEA TEMPERATURESchange by 2090 from present day (C)
75°N
60°N
45°N
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HadC
M3 G
HG
1
30°N
15°N90°W 60°W 30°W 0
–4.5 –3 – 1.5 0 1.5 3 4.5
UNCERTAINTIES IN CLIMATE CHANGE PREDICTIONS
• projections of future emissions• initial climate conditions• natural and human climate factors• realism of the climate model
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• realism of the climate model– feedbacks– resolution– extremes of climate
• surprises• estimating uncertainty• climate variability over the next decade
IPCC SRES99 CO2 EMISSIONS(Fossil fuels, GtC per year)
20
25
30
A1
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0
5
10
15
1990 2020 2050 2100
A2B1B2
4
2
3
4Te
mpe
ratu
re r
ise
/ deg
C
GLOBAL TEMPERATURE RISE due to the IPCC SRES99 emissions scenarios
Hadley EBM climate sensitivity=2.5KA1A2B1B2
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0
1
2
Tem
pera
ture
ris
e / d
eg C
2000 2020 2040 2060 2080 2100
GLOBAL TEMPERATURES UNDER KYOTO PROTOCOLdue to IPCC ‘business-as-usual’ and three post-Kyot o scenarios
IS92a
Only Kyoto
B constant
B-1% p.a.
Tem
pera
ture
ris
e/
°C
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4.0
3.0
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2100208020602040202020000.0
1.0
2.0
Tem
pera
ture
ris
e/
UNCERTAINTY DUE TO INITIAL CONDITIONSAn ensemble of projections of warming due to 1% per year increase in CO 2
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HadC
M2 G
HG
GLOBAL-MEAN RADIATIVE FORCING(pre-industrial to 1992)
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Source: IPCC
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CLOUDS AND CLIMATE
Low clouds reflect sunlight but trap little infra-red radiation;
They act to cool climate
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High clouds reflect sunlight but also trap infra-red radiation;
They act to warm climate
Global warming may change the characteristics of clouds, and thus alter their current net cooling effect; th is could
exert a powerful feedback on climate change .
The Met.Office C-130 RESEARCH AIRCRAFT
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SIMULATED WINTER PRECIPITATION
300kmGlobal Model
50kmRegional Model
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Mm/day
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25kmRegional Model
Observed
WINTER
SEA SURFACE
TEMPERATURES
in the
NORTH
ATLANTIC
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ATLANTIC
1945 - 1999
HadISST3.0
Florida Distance along track (x 1000km) Scotla nd
Sea Surface Temperature anomaly (K)
GLOBAL MEAN SURFACE TEMPERATURE1860-1998
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Global surface temperaturesrelative to average for 1961-90
0.4
0.5
0.6
Cha
nge
(deg
rees
C)
1
23
4
5
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0
0.1
0.2
0.3
80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98
Cha
nge
(deg
rees
C)
10
5
67 89
GLOBAL TEMPERATURE RISEobserved from three independent sources
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0.6
0.4
0.2
0.0
Diff
eren
ces,
oC
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0.0
-0.2
-0.4
-0.6
-0.8
Diff
eren
ces,
Sea surface
Night marine air
Land surface
1860 1880 1900 1920 1940 1960 1980 2000
THE EL NINO OF 1997/98Sea surface temperature anomalies in November 1997
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EL NINO AND LA NINA, 1870-1998GJJ1999
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Changes in sea-surface temperature for the eastern tropical Pacific off Peru.
Tem
pera
ture
cha
nge
deg
rees
C
OBSERVATIONS OF TEMPERATURE CHANGEat the surface and in the atmosphere
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1.5
Atmosphere
Surface
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Tem
pera
ture
cha
nge
deg
rees
C
1.0
0.5
0.01970 1975 1980 1985 1990 1995 2000
Causes of recent climate change
• Has climate changed? - monitoring
• Is the change unusual? - detection
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• Is the change unusual? - detection
• What are its causes? - attribution
CLIMATE CHANGE DUE TO CHANGES IN EARTH’S ORBIT
Temperature changes deduced from Antarctic ice cores (Russian-French Vostok analysis)
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Source: IPPCC
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1374
1372
Sol
ar r
adia
tion
/ W
m–2
CHANGES IN SOLAR ACTIVITY
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1370
1368
1850 1900 1950 2000
Sol
ar r
adia
tion
/ W
m
0.15
Rel
ativ
e ab
sorp
tion
of s
unlig
ht
CHANGES IN VOLCANIC AEROSOL
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Source: Sato
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0.10
0.05
0.00
1850 1900 1950
Rel
ativ
e ab
sorp
tion
of s
unlig
ht
2000
0.3
0.4
0.5
Atm
osph
eric
sul
phur
/ T
g
340
360
380
CO
2 co
ncen
trat
ion
/ ppm
Mauna LoaObservatory
Carbon dioxide Sulphateaerosol
CHANGES IN HUMAN FACTORSGJJ1999
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20001900180017000.0
0.1
0.2
Year
Atm
osph
eric
sul
phur
/ T
g
2000195019001850180017501700260
280
300
320
CO
2 co
ncen
trat
ion
/ ppm
ice cores
NATURAL VARIABILITY OF CLIMATE
0.2
0.4
0.6
0.8
1.0Model controlObserved
Tem
pera
ture
var
iatio
n (
°C)
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–0.4
–0.2
0.0
0.2
Tem
pera
ture
var
iatio
n (
2000 2200 2400 2600 2800
Year
HadC
M2 G
HG
GLOBAL MEAN SURFACE TEMPERATUREsimulated and observed
2.0
1.5
1.0
Greenhouse gases onlyAll anthropogenic factorsObserved
Tem
pera
ture
diff
eren
ce (
°C)
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HadC
M3
0.5
0.0
–0.51860 1880 1900 1920 1940 1960 1980 2000
Year
Tem
pera
ture
diff
eren
ce (
SURFACE AIR TEMPERATURE
change from 1880-1920 to 1975-95
Observed–1 –0.5 0 0.5 1 1.5 2
90°W 0° 90°E
90°N
45°N
45°S
90°S180°
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Simulated
HadC
M2
90°W
–1
0° 90°E
–0.5 0 0.5 1 1.5 2
90°N
45°N
45°S
90°S180°
TEMPERATURE TRENDS IN THE ATMOSPHERE1961 - 1996
1520
90°N
Hei
ght (
km)
0
5
10
1520
45°N 0° 45°S 90°SObserved
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Hei
ght (
km)
0
5
10
15
°C / year
90°N 45°N 0° 45°S 90°S
–0.08 –0.06 –0.04 –0.02 0 0.02 0.04
HadC
M2 G
HG
Simulated
ATTRIBUTION OF RECENT CLIMATE CHANGE
• Comparison of model simulated patterns of change (“fingerprints”) with those observed
• changes in time and space and by season ; discriminates against eg solar and volcanic
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discriminates against eg solar and volcanic
• gives low weight to areas of high natural variabili ty
• indicates human-made activities are largely responsible for changes since 1945
• NB: assumes patterns of change and natural variability are adequately simulated by model