New Scientist - Arctic Modeling With "Locked" Albedo Changes Only Cut Warming By 15%

[hatrack]

It might be one of the coldest regions on the planet but the Arctic is warming twice as fast as the rest of the globe - and now we know the reasons why. Two new studies show that the greenhouse effect is stronger above the North Pole, and that the waters of the Arctic Ocean are acting like a radiator to heat the region's atmosphere.

The warming of the Arctic warming has been explained before as being due to a positive feedback loop: as the ice cap melts and disappears, more of the dark ocean is exposed: the Arctic's reflectivity, or albedo, decreases. This means less energy is reflected back out into space and the region warms still further. But that infamous arctic albedo feedback is only a small part of the problem, Rune Graversen of the Royal Netherlands Meteorological Institute and Minguiai Wang of the University of Michigan have now shown.

The pair ran two nearly identical computer models of Arctic conditions. One model reflected the idea that the albedo of the Arctic reduces as temperatures rise and ice melts, but in the other the albedo didn't change. Graversen and Wang found that even in the model where albedo was "locked", Arctic temperatures continued to warm at well above the rate for the rest of the globe. Preventing the albedo feedback only decreased warming by 15%, indicating that it is not a driving factor behind the Arctic hothouse.

"The results are consistent with earlier work," says Andrew Barrett of the US National Snow and Ice Data Center in Boulder, Colorado, suggesting that decreasing reflectivity was not the dominant factor driving Arctic warming.

EDIT

http://www.newscientist.com/article/dn16623-arctics-personal-greenhouse-turns-up-the-heat.html?DCMP=OTC-rss&nsref=climate-change

[RaleighNCDUer]

1. It may not be the dominant factor

but it sure doesn't help.