The Current State of Our Climate Prof. Tim Raymond Chemical Engineering Dept. Bucknell University Focus the Nation – Obstacles to Change January 31, 2008

1/31/08Bucknell University2

1/31/08Bucknell University3 History and Background 1800’s - CO 2 at 290 ppm; T = 13.6°C 1800’s - CO 2 at 290 ppm; T = 13.6°C Fourier discovers natural ‘greenhouse effect’ of atmosphere Fourier discovers natural ‘greenhouse effect’ of atmosphere Swedish scientist Arrhenius predicts ‘greenhouse warming’ from CO Swedish scientist Arrhenius predicts ‘greenhouse warming’ from CO CO 2 at 315 ppm (up 9% from 1800) CO 2 at 315 ppm (up 9% from 1800) 1970’s - Unusual weather creates speculation on global warming/cooling 1970’s - Unusual weather creates speculation on global warming/cooling

1/31/08Bucknell University4 History and Background 1981 – Hansen shows previous cooling trend was from aerosols (pollution) 1981 – Hansen shows previous cooling trend was from aerosols (pollution) 1985 – Ice cores confirm correlation of CO 2 and temperature 1985 – Ice cores confirm correlation of CO 2 and temperature First IPCC report: world has been warming and future warming seems likely First IPCC report: world has been warming and future warming seems likely Second IPCC report detects "signature" of human-caused greenhouse effect warming Second IPCC report detects "signature" of human-caused greenhouse effect warming

1/31/08Bucknell University5 History and Background Third IPCC report: unprecedented global warming Third IPCC report: unprecedented global warming Studies find surprisingly strong "global dimming" (pollution) has masked intensity of greenhouse warming Studies find surprisingly strong "global dimming" (pollution) has masked intensity of greenhouse warming Kyoto treaty goes into effect Kyoto treaty goes into effect Fourth IPCC report: unequivocal warming Fourth IPCC report: unequivocal warming CO 2 at 382 ppm; T = 14.5°C (up 32%) CO 2 at 382 ppm; T = 14.5°C (up 32%)

1/31/08Bucknell University6 Annual Average Global Surface Temperature Anomalies

1/31/08Bucknell University7 Annual Average Global Surface Temperature Anomalies Cooling from Pollution Warming

1/31/08Bucknell University8

1/31/08Bucknell University9 Scientists know with virtual certainty that: Human activities are changing the composition of Earth's atmosphere. Human activities are changing the composition of Earth's atmosphere. The atmospheric buildup of CO 2 and other greenhouse gases is largely the result of human activities. The atmospheric buildup of CO 2 and other greenhouse gases is largely the result of human activities. An “unequivocal” warming trend of about 1.0 to 1.7°F occurred from An “unequivocal” warming trend of about 1.0 to 1.7°F occurred from The major greenhouse gases emitted by human activities remain in the atmosphere for periods ranging from decades to centuries. The major greenhouse gases emitted by human activities remain in the atmosphere for periods ranging from decades to centuries. Increasing greenhouse gas concentrations tend to warm the planet. Increasing greenhouse gas concentrations tend to warm the planet.

1/31/08Bucknell University10 Body of Evidence Increase of global average air temperature Increase of global average air temperature Increase is ocean water temperatures Increase is ocean water temperatures Decrease in Arctic sea-ice extent/thickness Decrease in Arctic sea-ice extent/thickness Decrease in glacier/ice cap extent/mass Decrease in glacier/ice cap extent/mass Rising global mean seal level Rising global mean seal level Changes in freeze/thaw, precipitation, etc. Changes in freeze/thaw, precipitation, etc.

1/31/08Bucknell University11

1/31/08Bucknell University12 Other Climate Variables Oceans are becoming more acidic (CO 2 ) Oceans are becoming more acidic (CO 2 ) “Observational evidence from all continents and most oceans shows that many natural systems are being affected” “Observational evidence from all continents and most oceans shows that many natural systems are being affected” –Permafrost: melting, instability, ecosystems –Ecosystems: early spring, animal ranges –Migrations: timing and extent

1/31/08Bucknell University13 What’s Not Certain? How much warming will occur How much warming will occur How fast it will occur How fast it will occur How the warming will affect the rest of the climate system How the warming will affect the rest of the climate system

1/31/08Bucknell University14 Summary of Current State “Warming of the climate system is unequivocal” “Warming of the climate system is unequivocal” Directly related to human activities Directly related to human activities Directly related to increases in GHGs Directly related to increases in GHGs Global effects already visible Global effects already visible

1/31/08Bucknell University15 Sources Observations of climate change: The 2007 IPCC Assessment, Testimony of Dr. Kevin E. Trenberth, Committee on Science and Technology, United States House of Representatives, February 8, 2007 Observations of climate change: The 2007 IPCC Assessment, Testimony of Dr. Kevin E. Trenberth, Committee on Science and Technology, United States House of Representatives, February 8, 2007 IPCC, 1996: Climate Change 1995: The Science of Climate Change. Eds. J. T. Houghton et al., Cambridge University Press, Cambridge, U.K. 572 pp. IPCC, 1996: Climate Change 1995: The Science of Climate Change. Eds. J. T. Houghton et al., Cambridge University Press, Cambridge, U.K. 572 pp. IPCC, 2001: Climate Change 2001: The Scientific Basis. Eds. J. T. Houghton, et al., Cambridge University Press, Cambridge, U.K. 881 pp. IPCC, 2001: Climate Change 2001: The Scientific Basis. Eds. J. T. Houghton, et al., Cambridge University Press, Cambridge, U.K. 881 pp. IPCC, 2007: Climate Change 2007: The Scientific Basis. Eds. S. Solomon, et al., Cambridge University Press, Cambridge, U.K. (in press). IPCC, 2007: Climate Change 2007: The Scientific Basis. Eds. S. Solomon, et al., Cambridge University Press, Cambridge, U.K. (in press).

1/31/08Bucknell University16 Sources