global warming ‘political hype or reality?’
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Global Warming ‘Political hype or reality?’. The Fernhurst Society - 5 April 2007 - John Clement. Global warming - questions. What is happening? What are the reasons? What is likely to happen from now on? What can we do?. What’s happening? Observable warming. - PowerPoint PPT PresentationTRANSCRIPT
Global WarmingGlobal Warming‘Political hype or reality?’‘Political hype or reality?’ The Fernhurst Society The Fernhurst Society
- 5 April 2007 -- 5 April 2007 -
John Clement John Clement
Global warming - questionsGlobal warming - questions
What is happening?What is happening?
What are the reasons?What are the reasons?
What is likely to happen from now on?What is likely to happen from now on?
What can we do?What can we do?
What’s happening? Observable warmingWhat’s happening? Observable warming
Trending strongly above long-term averages Trending strongly above long-term averages since mid ‘70-ssince mid ‘70-s
NOTNOT the Earth’s long-term climate cycle the Earth’s long-term climate cycle
‘000 years before present
-
+ 5 -
0 -
- 5 -
-
This cycle is driven by Earth’s orbit changes
What’s happening? Consistent observationsWhat’s happening? Consistent observations
Similar trending since mid ‘70-s by three Similar trending since mid ‘70-s by three independent measuresindependent measures
What are the reasons? The climate systemWhat are the reasons? The climate system
What are the reasons? Radiation balanceWhat are the reasons? Radiation balance
Energy coming into the Earth Energy coming into the Earth from the Sun — SOLAR radiationfrom the Sun — SOLAR radiation
Energy leaving the Earth to outer Energy leaving the Earth to outer Space — INVISIBLE Space — INVISIBLE
INFRARED radiationINFRARED radiation
Solar radiation at poles and equatorSolar radiation at poles and equatorNear the poles, the Sun’s rays are spread out
over a wide area, so the heating is less intense
Near the equator, the Sun’s rays are spread out over a smaller area, so
the heating is more intense
The Earth’s climate systems in the atmosphere and oceans transport heat between the equator and the poles
- and produce the ‘weather’
SUN’S RAYS
Range of global temperaturesRange of global temperatures
What are the reasons? Is it solar radiation?
Implied changes in global tem
perature (°C)
What are the reasons? Solar radiation?What are the reasons? Solar radiation?
0.1
0.2
0
Solar radiation – has been Solar radiation – has been stablestable for the last for the last 50 years50 years
What is the reason? What is the reason?
Energy coming into the Earth Energy coming into the Earth from the Sun — SOLAR radiationfrom the Sun — SOLAR radiation
Energy leaving the Earth to outer Energy leaving the Earth to outer Space — INVISIBLE Space — INVISIBLE
INFRARED radiationINFRARED radiation
What is the reason? The ‘greenhouse’ effect?What is the reason? The ‘greenhouse’ effect?
What is the reason? The ‘greenhouse’ effect?What is the reason? The ‘greenhouse’ effect?
Greenhouse gas increases through Industrial Age Greenhouse gas increases through Industrial Age
COCO22 – roughly constant at 280 ppm until 1800 – – roughly constant at 280 ppm until 1800 – then rising rapidly to 380+ ppm today, and then rising rapidly to 380+ ppm today, and
further yet.further yet.
Methane – 800 ppb until 1800, Methane – 800 ppb until 1800, now 1,750 ppb.now 1,750 ppb.
Nitrous oxide 270ppb until 1800 – now 310 ppbNitrous oxide 270ppb until 1800 – now 310 ppb
Lower atmosphere ozone increased around 30% Lower atmosphere ozone increased around 30% over the same period.over the same period.
Greenhouse gases Greenhouse gases Predicted warming effect over the next 100 years Predicted warming effect over the next 100 years
Methane24%
Carbondioxide
63%
Nitrousoxide 10%
Others3%
CO2 is the major contributor CO2 is the major contributor
Volcanoes also affect the atmosphereVolcanoes also affect the atmosphere
Volcanic aerosols in the atmosphereVolcanic aerosols in the atmosphere
5
4
3
2
1
0
5
4
3
2
1
0
Estim
ated cooling effect, Wm
1883 Krakatau
1980
Mt. St. Helens
1991 Mt. Pinatubo
What’s happening? Observable warmingWhat’s happening? Observable warming
Trending strongly above long-term averages Trending strongly above long-term averages since mid ‘70-ssince mid ‘70-s
Suspected effect of atmospheric particulates
Climate models - improvingClimate models - improving
Natural factors alone do not explain the pattern of Natural factors alone do not explain the pattern of global warming since industrialisationglobal warming since industrialisation
COCO22 in the atmosphere – long term stability until in the atmosphere – long term stability until
industrialisationindustrialisation
The Industrial
Age
COCO22 from fossil fuels – rapid rise since 1950 from fossil fuels – rapid rise since 1950
Addition of man-made factors to models Addition of man-made factors to models
duplicates observationsduplicates observations
Q. Global Warming?Q. Global Warming?
Change between 1750 and 2000
A. Man-made gases dominateA. Man-made gases dominate
Global warming - questionsGlobal warming - questions
What is happening?What is happening?
What are the reasons?What are the reasons?
What is likely to happen from now on?What is likely to happen from now on?
What can we do?What can we do?
Global warmingGlobal warming
What is happening?What is happening?
What are the reasons?What are the reasons?
What is likely to happen from now on?What is likely to happen from now on?
What can we do?What can we do?
What is likely to happen from now on? What is likely to happen from now on?
Depends on what we do.Depends on what we do.
Slowing down GHG emissions, particularly carbon, Slowing down GHG emissions, particularly carbon, will mitigate future temperature rises – but there is a will mitigate future temperature rises – but there is a lot of momentum already embedded in the climate lot of momentum already embedded in the climate system. system.
Adaptation will be needed for coming changes in Adaptation will be needed for coming changes in – – rainfall patternsrainfall patterns- glaciers and sea-ice - glaciers and sea-ice - sea-levels - sea-levels - land temperatures- land temperatures- food crop, forest and animal ranges- food crop, forest and animal ranges- human impacts – livelihoods, wealth and health- human impacts – livelihoods, wealth and health
RainfallRainfall
Glaciers and sea-iceGlaciers and sea-ice
Sea levelsSea levels
Land temperaturesLand temperatures
Rainfall - changingRainfall - changing
UK precipitation by 2080sUK precipitation by 2080s
European summer rainfall outlook - 2080sEuropean summer rainfall outlook - 2080s
RainfallRainfall
Glaciers and sea-iceGlaciers and sea-ice
Sea levelsSea levels
Land temperaturesLand temperatures
Glaciers – meltingGlaciers – melting
16,700 in the world – 13,500 are in retreat16,700 in the world – 13,500 are in retreat
Gangotri glacier, Himalayas – a case studyGangotri glacier, Himalayas – a case study
Himalayan glaciers - criticalHimalayan glaciers - critical
Himalayan glaciers feed 7 of Asia’s great rivers
- The Ganges
- The Indus
- The Brahmaputra
- The Salween
- The Mekong
- The Yangtze
- The Yellow river
Himalayan glaciers - criticalHimalayan glaciers - critical
2.3 billion people
RainfallRainfall
Glaciers andGlaciers and Sea-ice Sea-ice
Sea levelsSea levels
Land temperaturesLand temperatures
Sea ice – also meltingSea ice – also melting
1.3 million km1.3 million km22 Arctic ice lost since mid-70s Arctic ice lost since mid-70s
Arctic sea-ice, maybe disappearing by 2080sArctic sea-ice, maybe disappearing by 2080s
West Antarctic and Greenland ice sheetsWest Antarctic and Greenland ice sheets
= 6m sea level rise = 7m sea level rise
1,000 years to melt , but……..
Oceans - The north Atlantic ConveyorOceans - The north Atlantic Conveyor
Hypothetical collapse in ocean currentsHypothetical collapse in ocean currents
Best forecasts of Atlantic circulationBest forecasts of Atlantic circulation– – its OK!its OK!
RainfallRainfall
Glaciers and sea-iceGlaciers and sea-ice
Sea levelsSea levels
Land temperaturesLand temperatures
Components of sea level riseComponents of sea level rise
Long-term momentum of sea-level risesLong-term momentum of sea-level rises
IPCC estimates of global mean sea-level riseIPCC estimates of global mean sea-level rise
North Sea storm surges by 2080North Sea storm surges by 2080
RainfallRainfall
Glaciers and sea-iceGlaciers and sea-ice
Sea levelsSea levels
Land temperaturesLand temperatures
European hot summers – human activity has European hot summers – human activity has roughly doubled the chancesroughly doubled the chances
European summer temperatures risingEuropean summer temperatures rising
2003
Global warming - questionsGlobal warming - questions
What is happening?What is happening?
What are the reasons?What are the reasons?
What is likely to happen from now on?What is likely to happen from now on?
What can we do?What can we do?
What can we do?What can we do?
Avoid unnecessary carbonAvoid unnecessary carbon
Be prudent with necessary carbonBe prudent with necessary carbon
Offset and seuester as much carbon as Offset and seuester as much carbon as possiblepossible
AdaptAdapt
COCO22 emissions reductions - the only emissions reductions - the only
route to stable concentrations.route to stable concentrations.C
O2 c
on
cen
trat
ion
(p
pm
) 750
650
550
450
350
2501990 2010 2030 2050 2070 2090
Year
◄ Pre-industrial concentration
Constant 1990emissions
Businessas usual
50% 1990emissions
No getting away from it – future warmingNo getting away from it – future warming
What can we do?What can we do?
Avoid unnecessary carbonAvoid unnecessary carbon
Be prudent with necessary carbonBe prudent with necessary carbon
Offset and sequester as much carbon as Offset and sequester as much carbon as possiblepossible
AdaptAdapt
Cross fingers for approx. 200 years!Cross fingers for approx. 200 years!
The EndThe EndThe Fernhurst Society The Fernhurst Society
- 5 April 2007 -- 5 April 2007 -
A presentation by John A presentation by John Clement Clement