Arctic sea ice reaches minimum for 2014

Reaches the sixth lowest extent since satellite observations began in 1979; continues multi-year downward trend in sea-ice cover

Alan Bailey

Petroleum News

The extent of the Arctic sea ice cover has reached what is likely to prove its minimum extent for 2014, the National Snow and Ice Data Center, or NSIDC, has reported. On Sept. 17 the sea ice extent fell to an area of 1.94 million square miles, the sixth lowest extent since satellite observations of the polar icecap began in 1979, NSIDC said. The ice extent minimum was 622,000 square miles above the lowest ever recorded, the minimum of 1.32 million square miles observed on Sept. 16, 2012.

Although this year’s minimum extent lies within two standard deviations of the 1981 to 2010 average minimum extent, this year’s observations remain consistent with a long-term downward trend in the area of the ice cover, NSIDC said.

This year the ice cover over the Barents and Kara seas remained more extensive than it had been last year. On the other hand, this year there was a notable lack of ice north of the Laptev Sea, with the ice melt extending to within 342 miles of the North Sea in that region, NSIDC said. And, unlike in recent years, the Northwest Passage around northern Canada has remained closed by ice; the Northern Sea Route around northern Russia has opened.

By contrast, the sea ice in the Antarctic, as it reaches its winter maximum extent for the year, has reached an extent that exceeds the previous maximum extent record, set in 2013, NSIDC said. In the past some scientists attributed the recently exceptionally large Antarctic winter maximum ice cover to strengthening circumpolar winds pushing ice away from the South Pole.

And, in evaluating the state of polar sea ice it is important to consider the thickness of the ice, as well as its surface extent. Recent years have seen a significant loss of stable, thick multi-year ice in the Arctic, with thin, less-stable young ice tending to become more prevalent.