Something chilling is happening in the Arctic.
Or actually, what's happening is not at all chilling. And that's what's so alarming.
As winter, supposedly, descends onto the North Pole, warm weather has persisted in the Arctic for weeks on end, while the amount of sea ice covering the world's northernmost ocean has hit lows never seen before for this time of year.
The sea ice has been so scarce, roughly 28% below the long-term average in October, and temperatures so unseasonably balmy that scientists, including many who have studied the effects of manmade global warming on the most sensitive polar regions for years, have been taken by surprise.
“Seeing extremes in the Arctic is becoming fairly routine in some sense, but this is quite unusual and there has been talk in the community regarding how out of whack things appear at the moment," Walt Meier, a research scientist at NASA's Goddard Space Flight Center Cryospheric Sciences Laboratory, told BuzzFeed News.
One reading from the Danish Meteorological Institute, for example, found that over the past several days temperatures have been about 36 degrees Fahrenheit higher than average around the North Pole.
Like much of the rest of the world, the Arctic has been hotter than normal this past year. Temperatures have been 7 to 13 degrees above average in the Russian Arctic, according to the World Meteorological Organization. Other Arctic and sub-Arctic regions in Alaska and Canada have been at least 5 degrees above average, the UN agency said.
The high and persistent temperatures this fall are particularly extraordinary, scientists said, because the region has already plunged into "polar night," the time of year when the sun no longer rises over the North Pole.
"Usually it is bitterly cold by this time of year, but at the moment it's barely cold enough to keep ice frozen in some spots," Daniel Swain, a climate scientist and postdoctoral fellow at UCLA, told BuzzFeed News.
Scientists explain the heat wave by pointing to a string of record-breaking hot months earlier this year, coupled with little ice coverage during the summer. That combination has left the Arctic Ocean with a belly full of heat that it is now discharging into the atmosphere.
The polar jet stream, an air current whipping around the northern latitudes from west to east, also has contributed to the higher temperatures by bringing warm air from the lower latitudes north — while pushing the frigid air normally cloaking the North Pole over Siberia.
“Siberia is no stranger to bitter cold, of course, but this ‘warm Arctic/cold continent’ pattern is definitely striking and will almost certainly be the subject of future scientific study,” Swain said.
The balmier conditions have given the surface of the Arctic Ocean little chance to freeze. The area of the Arctic Ocean covered by some sea ice was at a record low for the month of October, according to data from the National Snow and Ice Data Center (NSIDC).
In the past week, a chart with a stark depiction of depleted sea ice at both poles attracted attention online. The graph combined the low Arctic winter ice extent with the steep drop of sea ice off Antarctica, just now entering its summer season.
But NSIDC, where the data in the graph reportedly originated, said it makes little sense to combine sea ice measures from both poles, which have vastly different geographies and are always in opposite seasons at any given time.
After the chart went viral, NSIDC was inundated with media inquiries about the graph. The center asked Meier, the NASA ice scientist, to verify the chart.
“I haven't been able to exactly recreate the plot,” Meier said. But he said that he was able to confirm that the combined sea ice coverage in Arctic and Antarctic are indeed at record lows.
Zachary Labe, a Ph.D. student in climate science at the University of California, Irvine, was one of the first people to tweet the chart. The chart was made by an internet user named “Wipneus” who, Labe told BuzzFeed News, has been posting on online sea ice forums and making visualizations for years.
It caught Labe’s attention because the data was so anomalous, but he agrees that it is better to consider Arctic and Antarctic sea ice separately.
“The atmospheric and sea ice dynamics between the Arctic and Antarctic are quite different,” Labe said. “The global sea ice plot may not be very meaningful.”
“I didn't realize there would be so much interest,” he added.
Regardless, the warm winter continues in the Arctic. But winters are long there, so there’s still plenty of time, said experts, for the ocean surface to freeze after the water cools and the warm air stops funneling north.
“Once that happens,” Meier said, “ice can grow rapidly.”