Global Warming Inconvenient truth handout Physics of anthropogenic global warming Key diagrams Consequences What can you do?
What causes Global Warming? • Addition of greenhouse gases to atmosphere • Main culprits are Carbon Dioxide, Methane, and water
Trees take up CO2 Animals Produce Methane CS Fig. 15.20 4
Basic Physics • Greenhouse gases trap heat in Earth’s atmosphere • Greenhouse gas concentrations have risen • Trapped radiation has been measured • Planet will warm!!!!
Has the burning of fossil fuels resulted in increased CO2 concentrations in the atmosphere? Yes! Measurements of air in Hawaii Measurements of ancient air preserved in ice
Bubbles in glacial ice preserve air of past cent- uries: Tell us what CO2 concentrations were like before the industrial revolution
Last Interglacial Current Longer records Current CO2 levels are well above range observed during recent geologic history associated with the ice ages
Can’t account For recent warming Can’t account For prior warming Works! Best evidence that recent warming is anthropogenic Three years in the 1990’s are the warmest in the Northern Hemisphere, by far, of the last 400 years! Data from Mann and others, Nature, 1998; Figure from IPCC 2001 Report
Consequences • Planet will warm • High latitudes will warm more than low latitudes • Sea level will rise • Questions: • How fast will warming and sea level rise occur • How will Earth’s weather patterns be affected
Global Temperatures projected to rise3 to 7 °F IPCC 2007 http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_spm.pdf
The maximum degree of global warming, as predicted by 95,000 home computers Stainforth, D. A. et alNature433, 403−406 (2005).
Change in Minnesota “Recent research indicates a warming trend in Minnesota. A study of the climate record at Fort Snelling shows an increase of 2.9°F in average annual temperature between the 1860s and 1987, almost three times the worldwide average. Analyses of more than a hundred temperature-depth profiles in North America show that ground latitudes comparable to Minnesota’s indicated ground warming of up to 3.6°F.” From “Playing with Fire, Global Warming in Minnesota” 1999; data from Baker and Skaggs, 1989
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