Weather security

The polar vortex is running wild—and it may not be because of climate change

As bitter cold and snow descended on the Midwest last week, a number of news outlets reported on a seemingly contradictory idea: that under climate change, these brief winter bursts of cold Arctic air could become more common in the continental United States.

The idea is indeed backed by some atmospheric scientists, who say that the rapidly warming Arctic could disrupt both the stratospheric polar vortex as well as the jet stream, or tropospheric polar vortex, and the main source of last week’s extreme cold. But other studies haven’t corroborated these findings, and the topic remains an area of active debate among scientists. Here’s why we can’t say for sure if climate change will bring more cold snaps in the U.S. in the future.

How a warming Arctic might bring us cold weather

As global temperatures warm, sea ice at the poles is melting and exposing the ocean to the sun’s heat. Because water absorbs more heat than ice, this raises temperatures and leads to more ice loss, which causes more temperature bumps, and so forth. As a result, temperatures in the Arctic are increasing at about twice the rate of midlatitudes.