Now that the latest frigid, deadly Arctic blast is giving way to warmer conditions in the Midwest and Northeast, some clarity is emerging on how to think about cold waves in a warming climate.

An initial blizzard of headlines gave the impression that this week’s cold, driven by the weakening of the “polar vortex”—miles-high winds circling the North Pole—was a monumental event, and some accounts projected worse to come under global warming.

But many climate scientists focused deeply on the response of extreme winter weather in a human-heated climate see a different picture, explaining that data clearly show a long-term trend toward fewer, less widespread and less severe cold snaps of this sort. And the pattern is not limited to the