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Climate change. Revd Professor Ian James Head of School of Mathematics, Meteorology & Physics, University of Reading Oxford Diocesan environment advisor Dr.I.N.James@Btinternet.com. Plan of talk. The problem Is climate change real? Some complications The future. The problem.
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Climate change Revd Professor Ian James Head of School of Mathematics, Meteorology & Physics, University of Reading Oxford Diocesan environment advisor Dr.I.N.James@Btinternet.com Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
Plan of talk • The problem • Is climate change real? • Some complications • The future Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
The problem - why climate change is a concern Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
Atmospheric carbon dioxide Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
A little goes a long way! Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
Infra-red view Visible light Two views of Earth Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
The “greenhouse” effect • Carbon dioxide blankets Earth’s surface. • Sunlight gets in. • Infra-red absorbed and re-emitted. • Other greenhouse agents – water vapour, clouds. Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
Carbon dioxide & ice ages Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
The 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 Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
What activities generate carbon dioxide? • All sources are comparable • No easy target! • Reduction across the board Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
Is climate change happening? Some examples Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
Variations of the Earth’s surface temperature for the past 1,000 years SPM 1b Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
Summer 2003 Temperature Anomaly June-August 2003 Deviation from 1961-1990 mean Based on ECMWF and ERA-40 Color: temperature anomaly Contours: normalized by standard deviation ºC Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com (Schär et al. 2004, Nature, 427, 332-336)
Hurricanes • More intense • More extremes • Form over hottest sea Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
Arctic sea ice September 2005 September 1979 Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
Pasterze glacier, Austria, 1875 Same view, 2004 Glaciers in retreat Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
Sea-level transgression scenarios for Bangladesh Adapted from Milliman et al. (1989). Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
Some complications…. Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
Feedbacks…… A positive feedback loop… Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
Examples of climate feedbacks • Warm atmosphere becomes moister • Melting ice & snow makes surface darker • Melting tundra releases methane • Moist atmosphere becomes cloudier Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
Melting 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 Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
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”? Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
The future? Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
Global carbon emissions from fossil fuels Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com
Only connect! • Interdependence of natural world • We are part of natural world! • Need to live sustainably within the entire world community Diocese of Oxford E-mail . Environment Advisor Dr.I.N.James@Btinternet.com