Friday, April 10, 2009

Earth's Arctic freezer warming up

Stephen Leahy at IPS: The world is losing its northern freezer aAdd Images Arctic winter ice is in sharp decline, NASA scientists reported this week. Even with below average winter temperatures, Arctic ice is thinner and covers less area than it did a decade ago.

Arctic sea ice is the cooling mechanism for the global climate system. As it declines and the region warms - already three to five degrees Celsius warmer - then inevitably there are local, regional and hemispheric climate impacts. "We’ve already lost one third of the summer ice cover since the 1980s. There are already impacts from this," says Ron Kwok of NASA's Jet Propulsion Laboratory in Pasadena.

"A completely ice-free summer by 2013 is not impossible," Kwok said in a telephone news conference. "You would have been laughed out the room if you suggested this five years ago." The new study shows that the maximum extent of the 2008-2009 winter sea ice cover was the fifth-lowest since researchers began collecting such information 30 years ago. The past six years have produced the six lowest maximums in that record.

More stunning, and indicative of the rapid warming of the region, is the decline in the thick, hard-to-melt multi-year ice, says Walter Meier, research scientist at the National Snow and Ice Data Centre in Boulder, Colorado. Multiyear ice is ice that is two or more years old and therefore doesn't melt in the summer. "Less than 10 percent is multiyear now. It used to be 30 percent in 1981," Meier said at the news conference.

Polar amplification is the reason why climate change is warming the Arctic far faster than anywhere else. A combination of processes and feedbacks in the region have resulted a three to five degree Celsius warming already. In 50 to 100 years time if average global temperature rises three degrees Celsius, the Arctic freezer will be a hothouse - at least 10 degrees Celsius warmer.

"The polar cryosphere has long existed as a buffer against [global] climate warming to an extent," Dick Peltier, Director of the Centre for Global Change Science at the University of Toronto, told IPS. …."It's a bit like a flywheel now able to turn with reckless abandon."

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