It’s well known that the rapidly warming Arctic is melting sea ice, thawing permafrost, and accelerating sea-level rise. But a growing body of research suggests, counterintuitively, that it could also be amplifying cold snaps, much like the brutal one now freezing the East Coast.

How it works: A number of climate scientists, including Jennifer Francis at Rutgers, believe that rising temperatures and declining sea ice in the Arctic may create a more meandering jet stream. That, in turn, allows elongated troughs of cold air usually trapped in the polar vortex above the North Pole to extend down into the mid-latitudes, creating persistent cold spells and a greater likelihood of snowstorms.

But: The science still isn’t settled on this topic. Evidence is building that the jet stream is becoming loopier, and that those changes are highly correlated with shifting Arctic conditions. 

But Kevin Trenberth, a climate scientist at the National Center for Atmospheric Research, stressed to the Washington Post in late 2016: “The problem with most if not all of the Arctic/jet stream studies has been the lack of a clear physical cause-and-effect relationship.”