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Thursday, March 10, 2011

What is Global Warming ? | PPT File

Title             : Global Warming
Author         : Hickey
Filetype       : ppt
Size               : 6,99 Mb
Slide             : 28
Category      : Climate
Download   : here 


Description :
Global warming is the increase in the average temperature of Earth's near-surface air and oceans since the mid-20th century and its projected continuation. According to the 2007 Fourth Assessment Report by the Intergovernmental Panel on Climate Change (IPCC), global surface temperature increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the 20th century. Most of the observed temperature increase since the middle of the 20th century has been caused by increasing concentrations of greenhouse gases, which result from human activity such as the burning of fossil fuel and deforestation.

Global dimming, a phenomenon of increasing atmospheric concentrations of man-made aerosols, which affect cloud properties and block sunlight from reaching the surface, has partially countered the effects of warming induced by greenhouse gases.

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