Monday, December 1, 2008

GLOBAL WARMING


Global warming is the increase of average temperatures on the earth’s surface, calculated annually from measurements taken across the entire globe. Scientists attribute the recent rise in average global temperatures to an increase in greenhouse gases which create the “greenhouse effect” of trapping heat from the sun in our atmosphere. These gases include water vapor, CO2, methane, nitrous oxide, and chlorofluorocarbons (CFC) among others. While the greenhouse effect is essential for life on earth – without it, surface temperatures would be about -2oF – excessive greenhouse gases can also elevate temperatures above livability range.

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