The Arctic is missing a chunk of sea ice the size of Texas, Arizona and Kansas
Arctic sea ice is limping toward its seasonal peak, hitting a record low for the month of February on the heels of another record set just the month before.
The region -- which acts as the northern hemisphere's refrigerator -- was missing a chunk of ice measuring about 448,000 square miles, compared to the 1981-2010 long-term average, according to the National Snow and Ice Data Center.
This departure from average is about the size of the states of Texas, Arizona and Kansas combined.
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The sea ice extent was about 77,000 square miles below the previous record February low, which was set in 2005.
The Arctic, more than perhaps any other region on Earth, has had a freakishly mild winter this year, with region-wide surface temperatures of more than 7.2 degrees Fahrenheit, or 4 degrees Celsius, above the 1951 to 1980 average during January. That is an astonishingly large anomaly for a region this large.
Air temperatures in the lowest layer of the atmosphere, just a few thousand feet above the surface, were 11 to 14 degrees Fahrenheit, or 6 to 8 degrees Celsius, above the 1981-2010 average over the central Arctic Ocean, including the area near the North Pole, the NSIDC said in a news release on Wednesday.
This is far from normal for the Arctic, especially considering that air temperatures at the North Pole have reached or possibly exceeded the freezing point at least twice during the January to February period, and that Alaska, Scandinavia and other regions have experienced winters that locals hardly recognize, with below average snowfall and temperatures much above average.
“For the Arctic this is definitely the strangest winter I’ve ever seen," Mark Serreze, the NSIDC director, told Mashable earlier this month. The entire Arctic was “just absurdly warm, I’ve never seen anything like that,” Serreze said of January's climate conditions in the far north.
In recent years, numerous studies have been published that show rapid Arctic warming may be altering weather patterns far from the Arctic Circle, including potentially altering the jet stream winds that steer storms across the U.S. and Europe.
While this is still an active area of research, it's becoming clearer that whatever happens in the Arctic likely does not remain safely ensconced in that region.
Freak warmth plus the right wind patterns
It typically takes more than just unusually mild temperatures to set low sea ice extent records. Atmospheric circulation patterns, such as the Arctic Oscillation, also have to align in ways that both pump mild air into the Arctic and flush sea ice out of the region and into the North Atlantic in particular.
The Arctic Oscillation is a pattern of air pressure differences between the Arctic and the midlatitudes that shifts between so-called "positive" and "negative" phases. In its negative phase, the oscillation favors milder conditions and increased ice transport away from the Arctic.
According to the NSIDC, weather patterns during February favored low sea ice extent in the Barents and Kara seas, with sea ice motion in the Barents preventing sea ice from advancing southward as it usually would.
More importantly, from the second half of January through much of February, a clockwise circulation pattern of air developed over the Beaufort Sea, north of Alaska. This eventually grew larger, and encompassed "most of the Arctic Ocean," the NSIDC stated.
"Whether this circulation pattern will continue and set the stage for very low September sea ice extent remains to be seen."
Such a weather pattern is important because it helps to push sea ice out of the passageway between the Norwegian Archipelago of Svalbard and Greenland, as if someone were flushing a giant North Pole toilet bowl, sucking sea ice through the Fram Strait and into the North Atlantic.
This sea ice transport has implications for the summer, since much of the ice that was flushed out of the region was older, thicker ice that is more resistant to melting during the summer melt season. However, it does not guarantee a record low sea ice minimum in September.
"Whether this circulation pattern will continue and set the stage for very low September sea ice extent remains to be seen," the NSIDC stated.
In fact, sea ice data for late February into early March shows a rebound in sea ice extent, closer to 2015 levels, though this may be short-lived.
At the end of February, sea ice extent was below average in the Barents, Kara, Bering and East Greenland Seas. In addition, the Gulf of St. Lawrence, which is normally chock full of ice at this time of year, is "largely ice free," the NSIDC said.
Illustrating feedback loops at work in the Arctic, the areas that had below average sea ice tended to be much milder and have more moisture in the air than areas that had a healthier amount of sea ice, the NSIDC found.
This is because darker open ocean waters absorb more incoming solar radiation, thereby warming the waters, melting more ice and warming the surrounding air. This feedback loop, also known as Arctic amplification, acts to accelerate sea ice melting.
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Andrew Freedman is Mashable's Senior Editor for Science and Special Projects. Prior to working at Mashable, Freedman was a Senior Science writer for Climate Central. He has also worked as a reporter for Congressional Quarterly and Greenwire/E&E Daily. His writing has also appeared in the Washington Post, online at The Weather Channel, and washingtonpost.com, where he wrote a weekly climate science column for the "Capital Weather Gang" blog. He has provided commentary on climate science and policy for Sky News, CBC Radio, NPR, Al Jazeera, Sirius XM Radio, PBS NewsHour, and other national and international outlets. He holds a Masters in Climate and Society from Columbia University, and a Masters in Law and Diplomacy from The Fletcher School at Tufts University.
