Arctic sea ice reaches lowest seasonal minimum on record

Arctic sea ice reached its minimum extent for the year on Sept. 16 to smaller than 3.5 square kilometres, the lowest seasonal minimum extent on record since 1979, the National Snow and Ice Data Center in the United States has reported.

The ice extent will grow during the autumn and winter, but shifting wind patterns or late season melt could push it lower, according to the NSIDC, based at the University of Colorado.

This year’s minimum extent of 3.41 million square kilometres is nearly half of what the average had been between 1979 and 2000, or a difference about twice the size of the state of Alaska.

Last year, the minimum extent reached 4.33 million square kilometres. The previous lowest minimum extent on record was in 2007, at 4.17 million square kilometres.

“Overall there was a loss of 11.83 million square kilometres of ice since the maximum extent occurred on March 20, 2012, which is the largest summer ice extent loss in the satellite record, more than one million square kilometres greater than in any previous year,” according to the NSIDC.

The centre cites warmer summer temperatures as one reason for the shrinking ice, along with a very strong storm over the central Arctic Ocean in August. The primary reason, however, is likely thinning ice cover being replaced by seasonal ice which is more likely to break and melt, NSIDC says.

The shrinking sea ice will have implications for the global climate, including warmer overall climates and colder winters in parts of the world.