The Arctic Ocean has been a strange place this winter, with the trend of record low ice continuing from 2016. Arctic ice extent has never been below 14 million km2 in February or March in the satellite record as analyzed by NSIDC aside from the first few days of February 2006 and 2016, but extent in the first 11 days of February 2017 has inched up to 13.9 only to fall back again. Other measures — area, thickness, and volume — also show record lows for this time of year. The broad area of thick ice north of Canada hasn’t materialized this winter, and instead, 90 percent of the thick ice is poised to flow out into the Atlantic over the next several months. Satellite and airplane photographs show ice that is softer and more broken up than you would expect in any season outside of August and September. A Russian convoy crossed the Arctic Ocean around the end of December with with supplies, the first wintertime cargo trip across the Arctic ice in the post-Soviet era. No one is saying the trip was easy, but with thin and fragile ice it wasn’t accompanied by the sense of peril that followed icebreakers around in prior decades. The broken ice is flowing freely through Nares Strait, the narrow strait at the northwest corner of Greenland, which normally would clog up from November through April. Open water has been spotted not just on the north coast of Alaska but even on the north coast of Greenland. There have been episodes of warm air crossing the Arctic Ocean to feed unseasonable warmth into eastern Canada and western Russia. Last week North Pole temperatures crept up to the freezing mark and possibly over, the result of a warm atmospheric river that originated in the Caribbean Sea. At points the normal winter cold has escaped from not only the Arctic Ocean but also Siberia, so that the Northern Hemisphere’s cold spots were found in places as unlikely as southwest Asia and the U.S. Rocky Mountains.
Mild winter conditions in the Arctic Ocean in the last few years have not mattered to the sea ice because normal winter weather always returned eventually, giving ice inside the Arctic Circle enough cold air to regenerate. The rule of thumb was that if fall weather gave way to winter before the last week of January, you would be assured of thick ice by April. This year for the first time that rule has been broken. Winter cold is already three months late, there is no sign of a cold snap on the way, and Siberia, which has come to the Arctic’s rescue in winters past, is not currently cold enough to cool off an ocean. We are now assured that the melting season will start with ice that is thinner than normal.
We don’t know exactly what this means for the coming summer in the Arctic Ocean because we’ve never seen this situation before. If we start the melting season with 10 percent less ice than ever before, does that mean the whole Arctic Ocean could melt out before the summer is over? It sounds unlikely, but we can only guess.