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As freezing season resumes, Arctic ice levels shatter record lows

Ben Anderson

When Arctic sea ice reached a new all-time low in August, scientists warned that the melting season was set to continue for several more weeks. Now, it appears that the thawing has stopped and freezing has resumed, and the National Snow and Ice Data Center (NSIDC) has gloomy news for the final tally of ice cover in the Arctic.

The NSIDC reports that the melting season appears to have ended Sept. 16, and at that time, it covered about 1.32 million square miles. The record low came more than a quarter-million square miles before, when scientists measured the extent at 1.58 million square miles in late August. The previous low was recorded in September 2007 at 1.61 million square miles.

Scientists cautioned that the statement that melting had stopped was preliminary and could shift with changing weather conditions, but cooling in the far north appeared to have ended the 2012 melting season.

"In response to the setting sun and falling temperatures, ice extent will now climb through autumn and winter," the NSIDC reported. "However, a shift in wind patterns or a period of late season melt could still push the ice extent lower."

NASA reports that in addition to an overall reduction in sea ice extent, the thickness of Arctic ice is also on the decline -- and climate predictions have underestimated the rapid degradation of seasonal sea ice.

"Climate models have predicted a retreat of the Arctic sea ice; but the actual retreat has proven to be much more rapid than the predictions," NASA climate scientist Claire Parkinson said. "There continues to be considerable inter-annual variability in the sea ice cover, but the long-term retreat is quite apparent."

Coinciding with the record low is a record seasonal decrease. Since the sea ice maximum for the year was measured March 20, the Arctic has lost nearly 12 million square miles of ice.

Overall, the sea ice extent this year was about 50 percent lower than the 1979-2000 average. 

The melting Arctic has implications for accelerated climate change -- studies have suggested that the rapid melting of Arctic ice may contribute to extreme weather events elsewhere on the globe.

Contact Ben Anderson at ben(at)alaskadispatch.com