Arctic sees winter warmth

Last month, temperatures in the high Arctic spiked dramatically, some 20 degrees Celsius above normal — a move that corresponded with record low levels of Arctic sea ice during a time of year when this ice is supposed to be expanding during the freezing polar night.

And now this week we’re seeing another huge burst of Arctic warmth. A buoy close to the North Pole just reported temperatures close to the freezing point of 0 C, which is tens of degrees warmer than normal for this time of year.

Although it isn’t clear yet, we could now be in for another period when sea ice either pauses its spread across the Arctic Ocean or reverses course entirely.

But these bursts of Arctic warmth don’t stand alone — last month, extremely warm North Pole tempera- tures corresponded with extremely cold temperatures over Siberia. This week, meanwhile, there are large bursts of unseasonally cold air over Alaska and Siberia once again.

It is all looking rather consistent with an outlook that has been dubbed “Warm Arctic, Cold Continents” — a notion that remains scientifically contentious but, if accurate, is deeply consequential for how climate change could unfold in the Northern Hemisphere winter.

The core idea here begins with the fact that the Arctic is warming up faster than the mid-latitudes and the equator, and it’s losing its characteristic floating sea ice cover in the process.

This also changes the Arctic atmosphere, the theory goes, and these changes interact with large scale atmospheric patterns that affect our weather (phenomena such as the jet stream and polar vortex).