NSIDC Reports Arctic Ice Extent in July Second Lowest in Satellite Record

The Arctic sea ice extent averaged for July was the second lowest in the satellite record, after 2007, according to the latest figures from the National Snow and Ice Data Center (NSIDC).

Average ice extent for July was 8.39 million square kilometers (3.24 million square miles), 1.71 million square kilometers (660,000 square miles) below the 1979 to 2000 mean, but 260,000 square kilometers (100,000 square miles) above the average for July 2007, the lowest July in the thirty-two-year satellite record.

Stormy, cloudy, and relatively cool weather persisted through the month, which helped slow the rate of ice loss. The daily rate of decline for July was 77,000 square kilometers (29,700 square miles) per day, close to the 1979 to 2000 average of 84,400 square kilometers (32,600 square miles).

That weather has also made it less likely that the upcoming 2010 sea ice minimum will set a new record. It would take a very unusual set of conditions in August to create a new record low, NSIDC said.

This past winter’s negative phase of the Arctic Oscillation transported old ice (four, five, and more years old) from an area north of the Canadian Archipelago. The ice was flushed southwards and westward into the Beaufort and Chukchi seas, as noted in April. Ice age data show that back in the 1970s and 1980s, old ice drifting into the Beaufort Sea would generally survive the summer melt season. However, the old, thick ice that moved into this region is now beginning to melt out, which could further deplete the Arctic’s remaining store of old, thick ice. The loss of thick ice has been implicated as a major cause of the very low September sea ice minima observed in recent years.

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