Noah Diffenbaugh is a Stanford climate scientist who performs similar analyses in the attribution of extreme events to climate change.

“I really admire the World Weather Attribution group for taking the lead on producing these near real-time rapid analyses using techniques and methods that have been peer reviewed,” he said, “and I think that’s really important.”

As for the event itself, Diffenbaugh pointed out that the Arctic is responding extremely rapidly to climate change — more rapidly even than scientists had predicted. “One interesting thing in looking at the history of the peer reviewed literature over the last decade and a half is that the climate models have, as a whole, have really been less sensitive, in the Arctic, than what’s happened in the real world,” he said.

But perhaps some of the strongest words came from Mark Serreze, who heads the National Snow and Ice Data Center, a top source for information on the state of the Arctic. Serreze said by email that notwithstanding what happened this November and December, what’s going on in the Arctic is well outside of the norm and has been for a while. It’s worth quoting in full, because it captures well what scientists see as a new “normal”:

This is only the most recent remarkable event that we’ve seen in the Arctic over the past decade. Last winter saw another impressive heat wave, when in late December, temperatures at the North Pole almost reached the melting point.  The seasonal maximum sea extent of last March was the lowest ever seen. Many people thought that we’d never see as little sea ice in the Arctic as we did in September 2007,  then along came 2012 which blew that record out of the water. There have been rain on snow events in winter, resulting in massive die-offs of reindeer. As some point, one has to admit that the string of remarkable events in the Arctic is more than just a string of unrelated coincidences.

December 28