Why So Many Nor'easters In March? New Research Suggests Climate Change May Be A Factor

Joe Mathieu: You're listening to WGBH's Morning Edition. This winter started off bitterly cold, then turned mild for a month or so, and then March hit. Three major storms already and more snow in the forecast today into tomorrow. Ironically, new research suggests climate change could be a big part of the equation. WGBH Radio science correspondent Heather Goldstone joins us now with more. Good morning, Heather. 

Heather Goldstone: Good morning.

JM: This is something, because a lot of people like to say 'So much for global warming, look how cold it is in March!'

HG: Happy Spring. 

JM: You too, by the way.

HG: Well, I mean, the thing is we have to realize that it's not like March storms are something new. A few years ago, I actually, with the help of some of the meteorologists over it Weather Underground, put together a list of historic march snow storms going all the way back to the great snow of 1717, which was actually four storms in about a week and a half that dumped at least five feet of snow. So if we think we've had a bad March, that one really started off like a lion.

JM: Wow.

HG: And then people may remember the April Fool's Day blizzard of 1997, about three feet of snow on April 1st. You know, so definitely these are not the first March storms ever, but this year storms, perhaps record-setting, specifically for the coastal flooding that we've been seeing and also the extent of the power outages that have hit us. 

JM: I guess it speaks to why climate change is a more appropriate term to use than global warming. How does that tie in, Heather? 

HG: Right. So this is an interesting one that the science really started emerging — and this idea that the Arctic, in particular, could be influencing our winter weather — started emerging several years ago, and it's been a little controversial because it's been hard to nail down exactly how warming in the Arctic would influence our winters. But the basic idea is that it's the temperature difference — the cold in the Arctic and the warmer temperatures farther south — that really fuel things like the jet stream and the prevailing winds that determine our weather, and the Arctic is warming at least twice, maybe as much as four times faster than the global average.

And so, as it's getting warmer, that temperature difference can actually break down and that starts to affect the jet stream. We've heard these terms like polar vortex in recent years, and then there was this new study which ironically was published last week as the storm was hitting on Tuesday, which kind of added to this and said, OK, there's another piece to this, which is that if that warming is strong enough it can reach all the way up high up into the atmosphere well above where planes fly up into the stratosphere, and the stratosphere can kind of act like a memory mechanism, hold onto that energy, radiate it back down to the jet stream later, and actually, the connection is strongest in the late winter, kind of like we're seeing right now.

JM: So is that — that is, in fact, then, what's been going on this month, this March. 

HG: Well, you know, we don't have any formal attribution. Nobody's gone, as we can at this point, with computer models and said, you know, these storms are are 20 percent more likely with climate change, or that sort of thing. But this is certainly what the senior author of that study, Jennifer Francis of Rutgers University, who's really pioneered this work, this is exactly what she says you would expect.

(SOUND CLIP OF JENNIFER FRANCIS)

Jennifer Francis: Mother Nature seems to really agree with us and has been giving us quite a few examples this winter. And this past nor'easter that we just had a couple days ago was the fifth what we'd call a bomb cyclone that we've had this year. It's really been an incredible winter.

HG: And to add to how incredible it's been, if you go up to the Arctic, the opposite of what we've been seeing, there have been temperatures above freezing at the North Pole; open water in the Arctic north of Greenland, where there would normally be thick sea ice. So we are seeing that pattern of a very warm Arctic can lead to a cold, snowy pattern here in New England.

JM: We're talking with WGBH science correspondent Heather Goldstone. Sounds like our weather patterns, then, are truly upside down. 

HG: Yeah, I mean, that's basically — there are certain metrics of, you know, this difference in temperature that have, in past years, literally flipped where we may even be warmer than the Arctic in some cases. And then in other cases, as I said, it's just that the temperature difference isn't as much and we get these dips in the Gulf Stream, we get kind of that cold arctic air spilling down as it did in Europe a few weeks ago, and as we've been experiencing here for for the month of March.

JM: And here we are with our fourth nor'easter. Heather Goldstone is our science correspondent and host of Living Lab Radio, which airs Sundays at noon here on WGBH. Major support provided by the Kendeda fund, investing in transformative leaders and ideas. Heather, thanks. Good luck with the storm.

HG: Yeah, you too.