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Is Climate Change Behind the Polar Vortex Consuming the US?

It's hard to decisively say that the extreme weather this month is the result of global climate change, but it's also hard to decisively say that it isn't. Thanks, science!
Photo by Flickr user Pink Sherbet Photography

The northeast corner of the United States is currently going through a real-life version of the movie Frozen, except not uplifting: Homes are iced over, enormous snow walls have ​trapped people inside Walmarts, and the region is experiencing what the ​Weather Channel called "one of the longest sub-freezing spells on record for the month of November." It's so cold outside that people are dying—as of today, one in ​New Hampshire, one in ​Michigan, and at least ​five in New York.

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And it doesn't appear to be relenting, either.  ​Washington DC announced a weather emergency yesterday in anticipation of even colder temperatures. In Buffalo, which set an all-time, nationwide record for snowfall in a 24-hour period this month, people are posting photos of their doors sealed shut by snow. Casper, Wyoming, broke a record with a temperature of minus 27 degrees on Wednesday.

So why is all this happening? I asked Dr. Jin-Ho Yoon, a climate scientist at the Atmospheric Sciences and Global Change Division Pacific Northwest National Laboratory, what was causing all of the extreme cold weather. He said climate change might be to blame for at least some of it.

"There are two potential causes: One is that the reduction of the Arctic sea ice can amplify the polar vortex," he said. In other words, as the sea ice melts, freezing-cold air escapes from the Arctic and travels elsewhere. Yoon co-authored a  ​recent study on the subject that pointed out that many of these cold spells tend to happen just after sea levels drop in the Arctic.

The other hypothesis, according to Yoon, is that "the change in the sea temperatures over the Pacific generates some wave of motion in the atmosphere, which we call the polar vortex." So rather than coming from the Arctic, the wave of cold is coming from the Pacific.

The big question here is whether this extreme weather is manmade, and Yoon said that it's hard to say for sure. Since there's so much variability in the climate, there's no way to definitively say which weather events are the result of human interference and which are the result of wholly natural causes. And, Yoon adds, there hasn't been enough scientific research about extreme cold fronts to make a strong argument about their possible connect to climate change.

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"The change in Artic sea ice is much easier to explain when the global warming happens, as we are likely to have a reduction in sea ice over the Artic," he said. "Once we have more evidence, I believe that the link to the human cause might be stronger."

Dr. Thomas Ackerman, who directs the Joint Institute for the Study of the Atmosphere and Ocean Professor at the University of Washington, isn't so sure about that. He told me that climate change doesn't really have anything to do with it, and there's nothing particularly nefarious about this month's weather.

"If you look at the averages for November in the past ten years, is this a huge anomaly out of a hundred Novembers? No."

Heavy snowfall in November is normal, he explained, because there's more water in the air than there is in the dead of winter, and a couple days of cold don't mean anything in the long run. "It'll warm up by the end of the weekend, and those temperatures will probably be above normal," he said.

When you look at the ​forecast on NOAA—the National Oceanic and Atmospheric Administration—it actually looks as though the northeastern United States is poised to be warmer than average this winter.

So then what's causing all of these people to literally freeze to death?

Ackerman chalked it up to human error and unpreparedness. "People got dumped on [with snow] before they were really ready for it."

Oh.

Follow Arielle Pardes on ​Twitter.