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It’s easy to forget about other places in the world, or even in your own country, when you’re out shoveling snow, or people who are homeless suffer the worst of urban cold snaps, or harbor seals on the Hudson River ride ice floes, or your city shuts down due to a mismanaged winter storm.
The polar vortex, normally tucked away much closer to the Arctic, has swept down several times this winter, bringing cold temperatures and snow to large segments of the U.S. east of the Rockies. Many experience this and either forget or doubt what the data show: that 2013 was the fourth-hottest year on record (or second-hottest without an El Niño), that greenhouse gas emissions are causing the atmosphere to trap more heat, that climate change is a problem.
But not only is this cold not unprecedented – it’s not even happening most places.
Courtesy of Climate Central, a look at historical frigid cold periods in some of the U.S. cities that are in a deep freeze this winter shows that the number of frigid nights have seen a steady decline over the last few decades. The polar vortex pulled thermometers below zero and prompted fears that the Super Bowl would be paralyzed by snow and frigid temperatures. In the end, the game was 49 degrees at kickoff, making it only the third-coldest Super Bowl ever – Seattle and Denver were actually colder than it was in the Meadowlands. The University of Maine’s Climate Reanalyzer shows how this cold has moved south, leaving the Arctic much warmer than normal, and parts of North America colder than normal as of Saturday.
Why the displaced cold? The polar vortex has been pulled south by an unusually extreme jet stream, which some scientists have suggested will happen more frequently in a warming world. This leaves the far north much warmer than normal. Consider Alaska.