ian james diocese of oxford e-mail. environment advisor [email protected] climate change...
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Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
Climate changeClimate change
Revd Professor Ian JamesHead of School of Mathematics, Meteorology &
Physics, University of Reading
Oxford Diocesan environment advisor
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
Plan of talkPlan of talk
• The problem
• Is climate change real?
• Some complications
• The future
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
The problemThe problem
- why climate change is a concern
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
Atmospheric carbon dioxideAtmospheric carbon dioxide
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
A little goes a long way!A little goes a long way!
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
Two views of EarthTwo views of Earth
Visible light Infra-red view
Ian James Diocese of Oxford E-mail . Environment Advisor [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 Diocese of Oxford E-mail . Environment Advisor [email protected]
Carbon dioxide & ice agesCarbon dioxide & ice ages
Ian James Diocese of Oxford E-mail . Environment Advisor [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 Diocese of Oxford E-mail . Environment Advisor [email protected]
What activities generate What activities generate carbon dioxide?carbon dioxide?
• All sources are comparable
• No easy target!• Reduction across
the board
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
Is climate change happening?Is climate change happening?
Some examples
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
Variations of the Earth’s surface temperature for the past 1,000 years
SPM 1b
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
Summer 2003Summer 2003
Deviation from 1961-1990 mean
Based on ECMWFand ERA-40
Color: temperature anomaly
Contours: normalized by standard deviation
(Schär et al. 2004, Nature, 427, 332-336)
ºC
Temperature Anomaly June-August 2003
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
HurricanesHurricanes
•More intense
•More extremes
•Form over hottest sea
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
Arctic sea iceArctic sea ice
September 1979 September 2005
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
Glaciers in retreatGlaciers in retreat
Pasterze glacier, Austria, 1875 Same view, 2004
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
Sea-level transgression scenarios for BangladeshSea-level transgression scenarios for Bangladesh
Adapted from Milliman et al. (1989).
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
Some complications….Some complications….
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
Feedbacks……Feedbacks……
A positive feedback loop…
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
Examples of climate feedbacksExamples of climate feedbacks
• Warm atmosphere becomes moister
• Melting ice & snow makes surface darker
• Melting tundra releases methane
• Moist atmosphere becomes cloudier
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
Melting permafrostMelting permafrost
• Vast areas of the high northern latitudes have permanently frozen soils – “tundra”.
• These are thawing out as warming accelerates
• Thawing releases methane• Methane is an even more
potent greenhouse gas than carbon dioxide
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
The “tipping point”The “tipping point”
• The point at which carbon dioxide levels are so high enough that feedbacks take over, and changes become irreversible.
• Are we approaching a “tipping point”?
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
Global carbon emissions from fossil fuelsGlobal carbon emissions from fossil fuels
Ian James Diocese of Oxford E-mail . Environment Advisor [email protected]
Only connect!Only connect!
• Interdependence of natural world
• We are part of natural world!
• Need to live sustainably within the entire world community