Larry O’Hanlon in Discovery News: Whether it's 5 million years ago or June 2010, it's becoming very clear that whenever the Earth's climate warms up a few degrees -- for whatever reason -- the Arctic multiples that warming by a factor of about three.Two new studies of past warming and cooling periods going back millions of years have found that the Arctic reliably amplifies whatever global climate is doing. If the world drops 3 degrees colder, the Arctic will see 9 to 12 degrees of cooling. If Earth warmed up 3 degrees, the Arctic steams up 9 to 12 degrees.
"What it reinforces is that the Arctic has very strong positive feedbacks," said Gifford Miller of the University of Colorado, who spoke to Discovery News via satellite phone from a research expedition in northwest Australia. This year, that could mean the Arctic could be the warmest ever recorded since data from NASA's Goddard Institute for Space Studies show that global temperatures in 2010 have reached record levels.
The most powerful of feedbacks in the Arctic is sea ice and snow cover, said Miller, the lead author on a paper about past "Arctic amplification" in the journal Quaternary Science Reviews. When ice melts more sunlight reaches the oceans or the ground, causing even more ice to melt. The opposite is also true: When there is more ice it reflects more solar energy back into space, and cools the Arctic down, which leads to more sea ice forming….
Polar Circle, on the Norwegian coast winter in 2005-2006, shot by Janter, who has released the image into the public domain
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