Sea ice hits record lows at both poles
Arctic temperatures have finally started to cool off after yet another winter heat wave stunted sea ice growth over the weekend. The repeated bouts of warm weather this season have stunned even seasoned polar researchers, and could push the Arctic to a record low winter peak for the third year in a row.
Meanwhile, Antarctic sea ice set an all-time record low on Monday in a dramatic reversal from the record highs of recent years.
Sea ice at both poles has been expected to decline as the planet heats up from the buildup of greenhouse gases in the atmosphere. That trend is clear in the Arctic, where summer sea ice now covers half the area it did in the early 1970s. Sea ice levels in Antarctica are much more variable, though, and scientists are still unraveling the processes that affect it from year to year.
The large decline in Arctic sea ice allows the polar ocean to absorb more of the sun’s incoming rays, exacerbating warming in the region. The loss of sea ice also means more of the Arctic coast is battered by storm waves, increasing erosion and driving some native communities to move. The opening of the Arctic has also led to more shipping and commercial activity in an already fragile region.
‘Unusual Winter’
Temperatures in the Arctic have repeatedly spiked since the beginning of the freezing season last fall. The influx of warmth is caused by storms moving up from the Atlantic Ocean dragging warm air with them.
“This has been a most unusual winter,” Julienne Stroeve, of the National Snow and Ice Data Center, which tracks sea ice levels, said in an email.
Air temperature 2 meters above the surface for the Arctic north of 80 degrees latitude for 2017 (red), compared to 2016 (yellow), and the long-term average (blue). (Zack Labe/ Danish Meteorological Institute)
During this latest event, temperatures above 80 degrees north latitude reached nearly 30°F (15°C) above normal winter temperatures of about -22°F (-30°C). Temperatures over the weekend peaked above even the maximum seen during last winter, another exceptionally warm one for the Arctic.
The temperature rise, along with the winds and waves churned up by the storm, can stymie sea ice growth and even cause local melt.
Sea ice coverage is particularly low in the Barents and Kara seas, which sit north of Scandinavia and Russia and have been in the path of those incoming storms. In Norway’s Svalbard archipelago, which lies midway between mainland Norway and the North Pole, snows melted over the weekend as temperatures rose above freezing.
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