Highlights
This year, for the second time in row, a warm Arctic is again influencing the Polar Vortex, allowing more cold wind to escape to the south and bringing cold to the U.S. East Coast, East-Central Asia and Europe.
In 2010, the extent of sea ice cover in the Arctic at its lowest point in September was 31 percent less than the 1979-2000 average. It was the third lowest year after 2007 and 2008.
Open water and water covered by thin ice allows heat stored in the ocean to escape to the atmosphere. The autumn release of heat weakens the winds that normally circle the North Pole and act as a fence keeping cold air in. When the circle of winds, the Polar Vortex, breaks down, cold air spills south.
James Overland, a scientist with the National Oceanic and Atmospheric Administration, described this Warm Arctic-Cold Continents pattern in a paper that was part of NOAA’s most recent Arctic Report Card.
Scientists have observed that the past five years have been the warmest period recorded in the Arctic. Last month, temperatures were unusually warm in areas that were ice-free in summer, including waters north of Alaska, and also in Greenland.
In a recent paper, Overland wrote: “The conventional meteorologists’ view is that this breakdown is just random chaos. But given that the most extreme value occurred last year, there has been a major breakdown two years in a row, and that large changes are occurring in the Arctic, it is not inconceivable that warmer Arctic temperatures play some role in pushing toward a breakdown of the Polar Vortex in some years.”
The source article Winter storms don't undermine global warming science, climate experts say was published January 30, 2011 by McClatchy Newspapers .
