The Arctic has warmed so much that it’s becoming a completely different climate than it was just a few decades ago, according to new research from the National Center for Atmospheric Research (NCAR), published today in the journal Nature Climate Change.
The "new Arctic" will be warmer and wetter than the one we're used to. While the North Pole seems a long way from Boston, the changes up there will likely lead to different weather patterns down here, says Jennifer Francis, a senior scientist at the Woodwell Climate Research Center in Falmouth.
Francis is an atmospheric scientist, and one of her specialties is how the changing Arctic climate is affecting weather elsewhere. She also lives much of the year on a sailboat, which gives her a unique perspective on climate change. WBUR sat down with her to discuss ice, wind, and what she's seen firsthand.
The interview has been edited and condensed for clarity.
The study that came today says that the Arctic climate is entering a new phase. Can you explain what that means?
This study is confirming what we've known for quite a long time, and that is that the Arctic is changing faster than just about anywhere else on the planet. And it has been undergoing fundamental shifts in what we normally define the Arctic as being.
Arctic sea ice is so diminished that even an unusually cold year will no longer have the same amount of summer sea ice that we saw in the 1950s. Why does this matter?
One of the most striking changes as a result of climate change — and there's absolutely no other thing that could be causing this — is the fact that the sea ice, the ice floating on the Arctic Ocean, has diminished by a huge amount in a very short time, over only 40 years. Half of the ice cover has disappeared in only 40 years. And this is just a breathtaking change. And it has all kinds of repercussions for the Arctic itself and also impacts on the rest of the globe.
Like what? The warming Arctic seems bad for people who live up there — all the permafrost is melting and you see photos of roads buckling and buildings collapsing. But how is it affecting the global climate?
Well, there's several ways, actually, that affect all of us around the globe, especially if you live along the coast as many people do in New England. As the Arctic loses this very white surface, both sea ice and also snow, it's absorbing a lot more of the sun's energy. This is contributing to global warming. And it's been estimated in a couple of recent papers that that increase in global warming — just because of the loss of ice and snow in the Arctic — is about 25 to 40 percent larger than it would be otherwise. So right off the bat, it's making global warming that much worse.
And because we're warming the Arctic so fast, we're melting that land ice faster as well. So glaciers are melting faster, the Greenland ice sheet is melting faster. And when you melt land ice, it, of course, melts into water. That water flows into the ocean, and it adds directly to sea level rise. So about half of sea level rise is caused by the melting of glaciers and ice sheets. We're seeing a big increase in the rate of sea level rise, and it's partly due to the fact that we're having much more liquid water coming off of these ice sheets in the Arctic.
Your research looks at how the warming Arctic affects weather patterns elsewhere. Can you discuss how it's affecting New England?
The rapid warming of the Arctic is affecting the winds that blow around the northern hemisphere, and those winds affect our weather patterns. There's a difference in temperature between the Arctic, which is, of course, cold, and areas farther south, and that difference in temperature is what drives the jet stream. The jet stream is this fast moving river of wind that blows all around the northern hemisphere. It creates the weather patterns that we see on TV weather maps, the highs and the lows. Anything that messes with the jet stream is going to mess with our weather patterns.
So when that north-south temperature difference is large, then the jet stream blows very strongly. But because we're warming the Arctic so much faster, that north-south temperature difference is getting smaller, and the jet stream is getting weaker.
And that means that the weather that you experience where you live is going to hang around for a long time. We're able to actually measure the persistence of weather conditions, and in fact, they really are becoming more persistent.
So if we have a heat wave in Boston, instead of sticking around for a day or two it might stay longer?
That's exactly right. So if we're in a pattern where we're getting lots of nor'easters coming up the coast, for example, that overall regime is more likely to stay in place. If you think back to March of 2018, for example, when we had four nor'easters come through within just that one month, it's because the pattern was basically stuck in one place.
Heat waves are also good examples. Droughts, stormy periods, cold spells, all of those things can become more persistent. And when they do, they're much more likely to lead to extreme weather events.
What about hurricanes?
Hurricanes really are not a product of the jet stream. They're a completely separate class of storms. But that said, there is new research suggesting that tropical storms overall are slowing down — they're just not moving as quickly as they used to. And so we're tending to see more of these storms like Harvey and like Florence. And it looks like Sally is going to be another one of these very slow-moving storms that can dump several feet of rain in one place.
If the Arctic warms up enough, will the jet stream just go away?
No, it won't, because it'll always be colder there than it is here just because of the sun's angle. It's dark, and it gets very cold. So the jet stream will always be there.
When you look at images of the sea ice disappearing, it's pretty alarming. Is it happening faster than scientists expected?
Scientists tend to be somewhat conservative and not very alarmist. So I would say that it's not a surprise that the ice disappeared as fast as it has. But there are other parts of the climate system that have changed faster than than we've expected. It's almost never the fact that, "oh, this didn't change as fast as we thought it would." It's almost always in the other direction.
You've been a world sailor for much of your life, and you live much of each year on a sailboat. Given your intimate relationship with the ocean, you must have seen some of these changes firsthand. Can you share some of what you've seen?
We were in the Bahamas just this past spring, places that we'd been a decade earlier. And what we found was, there was no coral. Just 10 years before, it had been these vibrant reefs that were full of life and just beautiful. And instead we found these hulks of dead coral covered in algae, almost no fish around. It was absolutely striking.
In other places, we've seen the effects of sea level rise, just sucking away the sand, taking away small sand islands that were on our charts but then just didn't exist anymore. And our charts were not old.
Stories like this can be kind of overwhelming and depressing. What can people do?
Yeah. So it is a lot of bad news. I mean, we are watching the climate system change before our very eyes. This year has been an unbelievable set of examples of that: the fires raging out there right now are absolutely made worse by climate change. It's happening now.
The good news is that it's not too late for us to slow it down and make it less bad for our grandkids. We can't make it go away, though. So I'm not going to stand up there and say, "if we just do this, it will all go away." That's just not true. But we can slow it down. We can make the future damage less bad. And it's very straightforward: We have to stop emitting greenhouse gases, period.
The very most important thing is to vote for leaders who get it, and are willing to make hard decisions, and are willing to not put their own career political careers first. The most important thing is for our leaders to step up and start doing things at a national level, state level, county level, town level, because it has to happen across the board. The sooner we get on this, the less bad it's going to be for those next generations.
The audio segment attached to this post is an interview between WBUR's Morning Edition host Bob Oakes and Jennifer Francis.
This segment aired on September 15, 2020.