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Greenhouse Effect and Global Warming

Greenhouse Effect and Global Warming

1Greenhouse EffectKey FactorsEarth-Sun Temperature DifferencesGreenhouse Gas ConcentrationsThe atmosphere is transparent to incoming solar radiation (short wave, high energy), outgoing terrestrial radiation (longer waves, lower energy) is absorbed by GHGs. (also relates to Black body radiation)WIENS LAW !!!2Energy Balance

3Greenhouse GasesCarbon dioxide CO2Methane CH4Nitrous oxide N2OFreons CFCs (totally anthropogenic)What makes it a GHG???Water vapor H2O4GHG Concentration Changes Years 1000-2000

5Global WarmingAn increase in global temperatures due to increases in the concentrations of greenhouse gasesIncreased CO2 concentrations exerts largest radiative forcing (i.e., explains bulk of temperature increase)NOT CAUSED BY STRATOSPHERIC OZONE DEPLETION6GHG SourcesCombustion of fossil fuels Deforestation (loss of sink)Slash and burn techniques release CO2Fewer trees, less photosynthesisFertilizersCFCsMethane

7Data Source: C.D. Keeling and T.P. Whorf, Atmospheric CO2 Concentrations (ppmv) derived from in situ air samples collected at Mauna Loa Observatory, Hawaii, Scripps Institute of Oceanography, August 1998. A. Neftel et al, Historical CO2 Record from the Siple Station Ice Core, Physics Institute, University of Bern, Switzerland, September 1994. See http://cdiac.esd.ornl.gov/trends/co2/contents.htmAtmospheric carbon dioxide (CO2) concentrations (1750 to present)

8Atmospheric Carbon Dioxide (CO2) Concentrations (1750 to present)

Preindustrial atmospheric CO2 concentrations were approximately 275 parts per million. Today concentrations are approximately 367 ppmv, an increase of over 30 percent.

Data Source: C.D. Keeling and T.P. Whorf, Atmospheric CO2 Concentrations (ppmv) derived from in situ air samples collected at Mauna Loa Observatory, Hawaii, Scripps Institute of Oceanography, August 1998. A. Neftel et al, Historical CO2 Record from the Siple Station Ice Core, Physics Institute, University of Bern, Switzerland, September 1994. See http://cdiac.esd.ornl.gov/trends/co2/contents.htmData Source: Marland et al, 1999. Carbon Dioxide Information Analysis Center. Cumulative carbon emissions, 1950-1996

9Cumulative Carbon Emissions, 1950-1996

In terms of historical contributions to the atmospheric buildup of emissions, the industrialized countries like the US have contributed roughly 80 percent of the carbon dioxide buildup in the atmosphere to date. On a country-by-country basis, the comparisons between the rich and poor countries are even more stark. Since 1950, the US has emitted a cumulative total of roughly 50 billion tons of carbon, while China (4.5 times more populous) and India (3.5 times more populous) have emitted only 15 and 4 billion tons respectively.

Data Source: Marland et al, 1999. Carbon Dioxide Information Analysis Center.

Variations in the Earths surface temperature10

11ImpactsRise in sea levelThermal expansion of the oceansMelting ice caps and glaciersClimatic shiftsShifts in agricultureIncrease in diseaseDeclines in biodiversityCoral bleaching

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Reducing GH Emissions13

Solutions14

15Global Agreements

IPCC Intergovernmental Panel on Climate Change 1988 UNEPRio de Janeiro 1992Kyoto Protocol 1997Ratified Nov. 2006 U.S. and Australia have not signed the treaty

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U.S. Position

Bush Sr. (1988 1992)

Clinton (1992 2000)

Bush Jr. (2000 2008)

Obama (2008 - )

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