Europe Was Colder Than the North Pole This Week. How Could That Be?
“It’s locking in that cold air at the high latitudes in the Arctic region,” Dr. Cohen said, comparing the
polar vortex to a dam holding back the frigid arctic air from the rest of the Northern Hemisphere.
Dr. Cohen is the author of a 2017 study that linked a warming Arctic to the intermittent blasts of cold
that those of us in the Northern Hemisphere have come to know as the polar vortex.
The North Pole is above the freezing mark in the dead of winter; there are no direct measurements there, but merging satellite data with other temperature data shows
that temperatures soared this week to 35 degrees Fahrenheit (2 degrees Celsius).
Norway recorded the lowest temperatures of the cold snap: minus 43 degrees Fahrenheit
(minus 42 Celsius) in the southeast part of the country on Thursday.
This has always happened from time to time, but a growing body of research suggests
that because of climate change the warming Arctic is weakening the polar vortex.
Dr. Cohen says the loss of ice creates patterns of high pressure near the Barents Sea and Kara Sea off northern Russia.
But sometimes that dam bursts as the polar vortex weakens and allows cold air to escape the Arctic to more temperate climes.
That high pressure blocks the low-pressure system of the polar vortex, weakening it in the process
When it behaves normally, the polar vortex helps trap cold air in the Arctic.