Arctic sea ice cover declines rapidly

Thanks to warmer than average air temperatures, the Arctic sea ice extent declined rapidly in May, bringing the ice extent toward the record May low that occurred in 2006, the National Snow and Ice Data Center announced June 8. In the continuation of a trend that has persisted since the winter of 2008-09, air temperatures were 4 F to 9 F above average in May across much of the Arctic Ocean, NSIDC said.

Following a late start to the melt season, the ice extent had been close to average in April but May’s rapid ice melt puts the ice extent below the extent in May 2007, the year that saw the ice cover shrink to its smallest minimum extent since satellite ice measurement began in 1979. However, 2010 will not necessarily see a new record in the minimum extent — that minimum extent, which generally occurs in September, will depend on weather and wind conditions over the next few months, NSIDC said.

NSIDC said that studies indicate that the sea-ice thickness and volume have declined along with the ice extent since 1979. A model developed by the University of Washington indicates that the decline in ice volume at the end of May has been especially rapid since 2007.

—Alan Bailey