Arctic getting darker, making Earth warmer

http://apnews.myway.com/article/20140218/DAC1H60O0.html

Feb 18, 3:00 AM (ET)
By SETH BORENSTEIN

WASHINGTON (AP) - The Arctic isn't nearly as bright and white as it used to be because of more ice melting in the ocean, and that's turning out to be a global problem, a new study says.

With more dark, open water in the summer, less of the sun's heat is reflected back into space. So the entire Earth is absorbing more heat than expected, according to a study published Monday in the Proceedings of the National Academy of Sciences.

That extra absorbed energy is so big that it measures about one-quarter of the entire heat-trapping effect of carbon dioxide, said the study's lead author, Ian Eisenman, a climate scientist at the Scripps Institution of Oceanography in California.

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While earlier studies used computer models, Eisenman said his is the first to use satellite measurements to gauge sunlight reflection and to take into account cloud cover. The results show the darkening is as much as two to three times bigger than previous estimates, he said.

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