The average June Arctic ice extent was the lowest in the satellite data record, from 1979 to 2010, according to the US National Snow and Ice Data Center (NSIDC). Arctic air temperatures were higher than normal, and Arctic sea ice continued to decline at a fast pace. June saw the return of the Arctic dipole anomaly, an atmospheric pressure pattern that contributed to the record sea ice loss in 2007.


The linear rate of monthly decline for June over the 1979 to 2010 period is now 3.5% per decade. This year’s daily June rate of decline was the fastest in the satellite record; the previous record for the fastest rate of June decline was set in 1999. This rapid decline was in part driven by ice loss in Hudson Bay. Source: NSIDC. Click to enlarge.

Arctic sea ice extent averaged 10.87 million square kilometers (4.20 million square miles) for the month of June, 1.29 million square kilometers (498,000 square miles) below the 1979 to 2000 average and 190,000 square kilometers (73,000 square miles) below the previous record low for the month of 11.06 million square kilometers (4.27 million square miles), set in 2006.

In June, ice extent declined by 88,000 kilometers (34,000 square miles) per day, more than 50% greater than the average rate of 53,000 kilometers (20,000 square miles) per day. This rate of decline is the fastest measured for June.

During June, ice extent was below average everywhere except in the East Greenland Sea, where it was near average.

Weather conditions, atmospheric patterns, and cloud cover over the next month will play a major role in determining whether the 2010 sea ice decline tracks at a level similar to 2007, or more like 2006, NSIDC said. Although ice extent was greater in June 2007 than June 2006, in July 2007 the ice loss rate accelerated. That fast decline led up to the record low ice extent of September 2007.

However, NSIDC said, it would not be surprising to see the rate of ice loss slow in coming weeks as the melt process starts to encounter thicker, second and third year ice in the central Arctic Ocean. Loss of ice has already slowed in the Beaufort and Chukchi Seas due to the tongue of thicker, older ice in the region noted in NSIDC’s April update.