The June summary is out from the NSIDC ([US] National Snow and Ice Data Center), and it has no real surprises, if you follow such things, but it does provide a lot of detail:
Rapid ice loss continues through June
Average June ice extent was the lowest in the satellite data record, from 1979 to 2010. 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.
Overview of conditions
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.
Conditions in context
At the end of May 2010, daily ice extent fell below the previous record low for May, recorded in 2006, and during June continued to track at record low levels. By the 30th of June, the extent was 510,000 million square kilometers (197,000 square miles) below the same day in 2006.
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. 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, 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 our April update.
June 2010 compared to past years
Average ice extent for June 2010 was190,000 square kilometers (73,000 square miles) less than the previous record low for June, observed in 2006; 620,000 square kilometers (240,000 square miles) below that observed in 2007; and 1.29 million square kilometers (498,000 square miles) below the average extent for the month.
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.
If you’re waiting to see if this is where I show an exceptional lapse in judgment and make a prediction about whether we’ll break the 2007 Arctic ice extent record, then you’ll have to keep waiting. Even I’m not that impetuous.
And while I have the chance, let me add yet another gratuitous plug for my graphics page.
(And yes, the usability of the graphics page sucks mightily right now, as more than one person has pointed out to me. It’s one of the 27,384 things I’m working on. As soon as I get something better ready for testing and feedback, all youse guys will be the first to know.)
