Despite concerns over global warming, scientists have discovered something that may have actually limited the impact of greenhouse gases in the atmosphere in recent years by reducing the amount of sunlight reaching the surface of the Earth. Global dimming was the subject of a recent special on the PBS science series NOVA featuring Beate Liepert.
global dimming

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April 14, 2006
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May 14, 2004
From 1960 to 1990, scientists have observed a 1.3% per decade decline in the amount of sun reaching the Earth’s surface. This phenomenon, coined “solar dimming,” is due to changes in clouds and air pollution that are impeding the sun's ability to penetrate. Scientists believe that the combination of growing quantities of man-made aerosol particles in the atmosphere and more moisture have caused the cloud cover to thicken.



