Arctic ice maximum second lowest on record

Alan Bailey

Petroleum News

This year’s maximum extent of Arctic sea ice cover, recorded on March 17, was the second lowest maximum extent seen since satellite observations began in the late 1970s, the National Snow and Ice Data Center has reported. The maximum extent for the year was 5.59 million square miles, 448,000 square miles below the 1981 to 2010 average. The four lowest maximum extents observed have all happened in the past four years, NSIDC said.

The lowest maximum extent ever recorded, at 5.57 million square miles, was observed on March 7, 2017.

This year’s season of ice growth ended with very low ice extents in the Bering Sea and in the Barents Sea. Low ice cover in these regions reflected a late freeze up in the autumn combined with persistently high winter temperatures. The freeze up in the Chukchi Sea was especially late because of the persistent northward flow of relatively warm ocean water through the Bering Strait. Then, in February, there was an early retreat of sea ice in the Bering Sea.

On the Atlantic side of the Arctic the sea ice cover remained below average for much of the winter, a phenomenon that also appears to have been linked to abnormally warm ocean water.

Air temperatures have remained well above average for most of the winter, with an extreme heat wave developing in February over the Arctic Ocean for the fourth winter in a row.

There was a late spurt in ice growth in part of the Barents Sea just prior to the winter maximum ice extent, while the start of the annual ice retreat was led by ice loss in the Bering Sea, the NSIDC said.

- ALAN BAILEY