Arctic sea ice headed for another record melt: scientists

This image shows the extent of the Arctic Ocean’s ice cover on July 10. You can see the much larger average ice extent from 1979 to 2000 in pink. (IMAGE/ NATIONAL SNOW AND ICE DATA CENTRE)

June 2011 saw the second lowest Arctic ice cover since 1979, continuing the downward trend of summer ice cover, says the National Snow and Ice Data Center in Colorado.

Ice extent shrank last month at an average rate of 80,800 square kilometres per day, about 50 per cent faster than the average drop recorded from June 1979 to 2000.

At this rate, the Arctic Ocean may be ice free in summer by 2030, said Mark Serreze, director of the NSIDC, calling the decline of the extent of the sea ice and its loss of thickness “an overall downward spiral.”

The average ice extent for June fell below that for June 2007, which, until now, had the lowest minimum ice extent at the end of summer.

June ice extent was lower than normal in much of the Arctic, but Siberia’s Kara Sea region had particularly low ice.

Ice has also started to break up off the coast of Alaska in the Beaufort Sea. These open water areas absorb the sun’s energy, which will help to further ice melt through the summer, scientists say.

Arctic sea ice has entered “a critical period of the melt season,” they say.

That’s because the weather over the next few weeks will determine whether the Arctic sea ice cover will again approach record low reached in 2007.

Air temperatures for this past June were 1 to 4 degrees Celsius warmer than average over most of the Arctic Ocean, except in the Beaufort and Greenland seas, where temperatures were near normal or slightly below normal, the NSDIC says.

High pressure also dominated most of the central Arctic, with the highest pressures over the Beaufort Sea.

As well, water temperatures may be warming, according to an article published recently in the journal Science, which showed that the flow of ocean heat into the Arctic Ocean from the Atlantic is now higher than at any time in the past 2,000 years.