school of mathematics, meteorology & physics, university...
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Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
Our high carbon presentOur high carbon present
Revd Professor Ian JamesSchool of Mathematics, Meteorology &
Physics, University of Reading
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
Atmospheric carbon dioxideAtmospheric carbon dioxide
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
Radiation budgetRadiation budget
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
Two views of EarthTwo views of Earth
Visible light Infra-red view
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
The “greenhouse” effectThe “greenhouse” effect
• Carbon dioxide blankets Earth’s surface.
• Sunlight gets in.• Infra-red absorbed and re-
emitted.• Other greenhouse agents –
water vapour, clouds.
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
The carbon cycleThe carbon cycle
• Fossil fuels (coal, oil, natural gas) are made of carbon and hydrogen.
• When burnt, they produce energy, water and carbon dioxide.
Human Natural
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
Effects of COEffects of CO22 increasesincreases
• Warmer climate – local variations• Changed patterns of rainfall – drought/flood• More extreme weather events – rain/wind• Melting of ice caps and glaciers• Rising sea levels
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
Key impactsKey impactsWater Increased water in moist tropics & high latitudes
Decreased water in mid-latitudes and semi-arid tropicsHundreds of millions suffer water stress
Eco-systems
30% plus species at risk of extinctionCoral mortalityCarbon loss from biosphereSpecies ranges shift; wildfire risks
Food Complex negative impacts on subsistence farmers, fishers and small holdersCereal productivity drops in tropicsCereal productivity rises, then falls in mid-latitudes
Coasts Increasing damage from floods & stormsSome 30% coastal wetlands lostMillions experience coastal flooding each year
Health Malnutrition, diarrhoea, cardio-respiratory & infectious disease increaseIncreased morbidity from heat waves, floods, & droughtsIncreased range of some disease vectors
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
Is climate change real?Is climate change real?
Some examples
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
Variations of the Earth’s surface temperature for the past 1,000 years
SPM 1b
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
Latest global mean temperaturesLatest global mean temperatures 18501850--20072007
Global average temperature
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
1840 1860 1880 1900 1920 1940 1960 1980 2000 2020
Tem
pera
ture
ano
mal
y fro
m 1
961-
1990
ave
rage
(o C
)
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
Ice core recordIce core record
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
Arctic sea iceArctic sea ice
September 1979 September 2005
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
Glaciers in retreatGlaciers in retreat
Pasterze glacier, Austria, 1875 Same view, 2004
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
The future: what limits?The future: what limits?
Maximum tolerable temperature rise?- around 2°C
What levels of carbon dioxide will produce this?
- between 450 – 540 ppmWhen do we get there?
- 23 to 44 years if BAU
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
UncertaintiesUncertainties
• Wide uncertainty of magnitude of global and especially regional climate change
• Clouds, ocean circulation, biology all complicate issue
• Separation of CO2 signal from intrinsic variability of climate system
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
CertaintyCertainty
• Dramatic and continuing rises of CO2
• Absorption of i-r by CO2
• Some warming already has occurred and will continue.
• Question: how much?
Ian James University of Reading, Department of MeteorologyE-mail: [email protected]
Today’s world viewToday’s world view