greenhouse effect

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greenhouse effect Raised temperature at a planet's surface as a result of heat energy being trapped by gases in the atmosphere. As the Sun's rays pass through Earth's atmosphere, some heat is absorbed but most of the short-wave solar energy passes through. This energy is re-emitted by the Earth as long-wave radiation, which cannot pass easily through the atmosphere. More heat is retained if there is a cloud layer. In the last 100 years, more heat has been retained due to increased levels of carbon dioxide (CO2) through the burning of fossil fuels. Tiny particles of CO2 form an extra layer, which acts like the glass in a greenhouse. The effect is compounded by damage to the ozone layer caused by chlorofluorocarbons. Scientists of the Intergovernmental Panel on Climate Change (IPCC) estimate that a doubling of the present carbon dioxide emissions could lead to global warming on the scale of an average surface temperature rise of between 1 to 3.5°C. See also Earth Summit

http://www.epa.gov/globalwarming/kids/greenhouse.html

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