UMAIR IRFAN: This is Science Friday. I’m Umair Irfan. As the globe has heated up, the polar regions of the Arctic and Antarctica have become the fastest-warming places on the planet. Melting sea ice, cracking ice shelves, and retreating glaciers are all changing oceans and contributing to sea level rise along shorelines around the world.

Just this year, the news has been dramatic– heat waves at both poles, a shattered ice shelf for the first time in Eastern Antarctica. And last summer, rain fell for the first time at the summit in Greenland. Over the last 20 years, the Arctic has lost about one third of its winter sea ice volume, even as researchers watch fracturing ice shelves with baited breath.

Before the grim news felt too overwhelming, we wanted to sit down with some scientists who study the poles. We want to talk about what’s happening with the ice, how else these regions have been changing in the last few decades, and what is complicating our understanding of these regions. We’re here to answer your questions about the Arctic and Antarctica. And a quick note that we’re recording this in a live call in Zoom today. For more information about how you can attend a live taping of the show in the future, check out our website, sciencefriday.com/livestreams.

Let me introduce my guests. Dr. Uma Bhatt is an atmospheric scientist at the University of Alaska Fairbanks studying the Arctic. And Dr. Oscar Schofield is a biological oceanographer at Rutgers University. He’s been working off the coast of West Antarctica for the last several decades. Hello, and welcome to Science Friday.

OSCAR SCHOFIELD: Thanks for having us.

UMA BHATT: Thank you very much.

UMAIR IRFAN: I guess we’ll start with you, Uma. You’ve been working as an atmospheric scientist in the Arctic. What are some of the mysteries you’ve been trying to solve in your research?

UMA BHATT: So my research is in the area of climate variability. So I have been applying climate understanding to understanding how tundra vegetation has changed and how wildland fire has changed due to climate change.

UMAIR IRFAN: And Oscar, you’ve been studying the oceans off of West Antarctica for 30 years now. What have you been doing there all this time?

OSCAR SCHOFIELD: So I work on the West Antarctic Peninsula, just south of South America. And that is one of the fastest winter warming places on the planet, so we’re studying, when you melt the ice, how does that ripple through the food web from the plankton to the penguins?

UMAIR IRFAN: Can you describe some of the changes that we’ve been seeing as it relates to climate change? And what else is happening beyond the visible stuff of melting ice sheets and, you know, retreating glaciers?

OSCAR SCHOFIELD: Yeah, so the big thing we’re seeing in certain areas around Antarctica is real significant declines in glaciers, retreats, and also declines in the sea ice– how much you get every single year. And that essentially structures the physics and chemistry for that part of the planet. And now we’re seeing it ripple through a lot of the organisms that live there. So you change how much the plants grow, how well the penguins breed year to year. And we’re seeing really large differences. At Palmer Station, we used to have 1,600 breeding pairs of penguins, and we’re down to about 500.

UMAIR IRFAN: Uma, same question. What are some of the changes we’ve seen already, and what are we missing in the popular conversation?

UMA BHATT: So overall, the temperatures have increased by almost 6 degrees since the ’60s, and that has caused a decline in sea ice, as you mentioned. So not just a decline in sea ice area, but also sea ice volume. Sea ice has different thicknesses.

And that impact of sea ice has many cascading impacts on the climate system. For example, the tundra has greened. There is increased coastal erosion because there’s less sea ice. And in general, the warming of the Arctic has led to a decline in permafrost, and that has implications to human infrastructure and a variety of other cascading impacts. And kind of last item I’ll mention is, because the sea ice has declined, that’s led to increased ship traffic in the Arctic, which has a whole host of other issues associated with it.

UMAIR IRFAN: And we have two experts here from opposite ends of the world. And I think it’s a lot– pretty easy for people to assume that the Arctic and Antarctica are mirror images of each other because they’re both cold and icy. But they’re not the same. Can you tell us a little bit about what makes the Arctic different from Antarctica?

UMA BHATT: So I’ll give the answer I give my students as a starting point. Antarctica is land surrounded by ocean. The Arctic is an ocean surrounded by land. But the ice in the Arctic is already on the ocean. And the ice in the Antarctic is on land. And I’ll let Oscar talk more about that.

And I think one of the other fundamental differences is the ocean interaction is very different with the global ocean in the Antarctic. In the Arctic, there really are connections only through the Bering Strait and through the North Atlantic, whereas that’s very different in Antarctica. And the final item is, in the Arctic, we have permanent settlements and people that are well connected through a variety of different networks.

OSCAR SCHOFIELD: Yeah, sort of building– I mean, Uma described it really well– yeah, the Antarctic is the only continent that’s surrounded by an ocean, a circumpolar ocean. That is one of the largest current systems on the planet, and it tends to isolate that land mass. That deep ocean current is really warm by Antarctic standards. It’s 3 to 4 degrees Celsius. And the areas that are melting is where that current is getting pushed close to the continent by a lot of changes in the atmospheric forcing that Uma studies.

UMAIR IRFAN: So I’ve been following the news a little bit about the Arctic and Antarctic recently, and seeing that there’s been major wildfires in Siberia, some of them north of the Arctic Circle. And we’ve seen that in previous summers as well. Not really a region that we associate with wildfires, but Uma, can you tell us a little bit about how unusual this is? And is this part of a broader pattern?

UMA BHATT: So wildfire is a natural part of the boreal system. But over the last several decades, the incidence of large acres burnt has increased in North America as well as Siberia. So the general conclusion is that we’re getting warmer, drier summers. And it doesn’t take much for fires to start, because it’s a continental climate, so it’s very dry to begin with.

So when we use climate models to project what’s going to happen in the future, we do see the incidence of these fires– bigger, longer fire seasons– increasing. Certainly, all the data in our analysis suggests that that is something we do need to be prepared for.

UMAIR IRFAN: And Oscar, you talked a little bit about the distinction between Eastern and Western Antarctica. Could you elaborate a little bit on why they’re different? And recently, we saw an ice shelf collapse in Eastern Antarctica, so why is that significant?

OSCAR SCHOFIELD: That is a big deal. So the Western Antarctic and the true Eastern Antarctica, the Totten Ice Shelf, represent areas that have a lot of that land ice that Uma talked about. We’ve been seeing that the Western side has shown really dramatic declines and glacier retreat. There is some evidence that we’re starting to see it in Eastern Antarctica. And it’s being driven by, essentially, the deep ocean, that circumpolar current that’s warm, getting underneath the ice sheets. And you sort of start melting the ice sheets from below.

And those are the two locations where that circumpolar current is closest to the continent. Other regions like the Weddell Sea and the Ross Sea are– the current is farther offshore. And that’s where we’re not seeing the decline. But the Totten Ice Shelf represents a huge proportion of the fresh water on the planet. It’s frozen on the land. And while it would take a very long time, if you melt a lot of that, that is a huge contributor to global sea level rise.

UMAIR IRFAN: We’ve got an audience question from Natalie about animal adaptation. She asks, “Is it possible for animals in these cold regions to adapt quickly enough to survive these massive temperature changes?” I imagine that’s different on the Arctic and Antarctic, but Oscar, can you talk about the Antarctica?

OSCAR SCHOFIELD: Yeah, in the Antarctic, that’s the million question. They are adapted in several ways. They have unique physiology. They show really strong seasonality. So a lot of them, like whales, will migrate down in the summertime when there’s a lot of food, but migrate back towards South America to breed in the summer.

And what we’re seeing, if you change when the sea ice is there, you change the timing of all that. And then that affects how much food is available when the animals need it. So if you have a penguin, an Adélie penguin, it needs to put 4 kilograms of blubber fat on its chick for that chick to survive the next winter. If you change the timing and the krill availability, that ripples directly into the food web very, very quickly.

UMAIR IRFAN: And how about in the Arctic, Uma? Can animals adapt to these warming? And how about the plants?

UMA BHATT: So some of the animals are adapting. For example, polar bears and walrus are spending more time on land. But that’s leading to other problems and more interactions with humans. So that’s what’s happening immediately. And the long term fate is the million-dollar question.

In terms of the marine ecosystem, there are whales, humpback whales and orca whales, who now come much farther into the Arctic and compete with local whales that live in the Arctic. So that, again, leads to potential instability.

UMAIR IRFAN: I mentioned up top that the poles are warming faster than the rest of the planet. Why is it that the coldest regions are heating up the fastest?

UMA BHATT: So the sea ice is basically a blanket in the Arctic that keeps the warm ocean from transferring its heat to the atmosphere. So when that blanket goes away, the ocean warms up because the sun shines all summer, and it amplifies that signal. So it’s a positive feedback and increases the warming. So we get much more warming once we decrease the sea ice. But we also get polar amplification from the transport from the tropics of moisture to the Arctic. So those are two key factors that lead to this amplified signal in the Arctic and the Antarctic.

UMAIR IRFAN: And Oscar, I’ve seen the term the Thwaites Glacier in the news a lot. Why is that such an important piece of ice in Antarctica? And how worried should we be over the next few years, over the next couple of decades, about what’s going on there?

OSCAR SCHOFIELD: Yeah, so the Thwaites Glacier is sort of in the Bellingshausen Sea, so it’s sort of south of where I work. It’s a large ice sheet. And it is what we call “is in runaway collapse.” And essentially, what that means is that warm, deep ocean is underneath. And so we are watching it essentially collapse and increase speed by which that ice on the land is moving out in the ocean.

It directly impacts sea level rise because that was ice on land that is now going into the ocean and melting, and can represent not parts of an inch of sea level rise, but inches. The big science question that a lot of people are working on right now– there was a large expedition earlier this year– is sort of, what’s the speed of that? And is it something that happens over five, 10 years, 50 years, before we see the full expression of sea level rise with that collapse? And it’s sort of an example of what we expect to see more of as the planet continues to warm.

UMAIR IRFAN: Now, both the Arctic and Antarctica are regions where a lot of different governments are working together, and scientists around the world are teaming up. But we’ve seen with recent current events, of course, that some of that is being disrupted. The Arctic Council, which is this overarching group of Arctic nations that teams up on things like working on science has been suspended since Russia invaded Ukraine. And I’m wondering, with these geopolitical disruptions, how does that affect research and your collaboration and cooperation with other scientists around the world?

UMA BHATT: I think it’s been devastating for the Arctic, in that people who do fieldwork in Russia have not been able to go. Russian scientists have not been able to attend meetings. And Russia is a huge part of the Arctic, physically. And it’s very much of concern to all scientists in the Arctic.

OSCAR SCHOFIELD: Yeah, I would argue the same thing for the Antarctic. The Antarctic is controlled by the Antarctic Treaty, which essentially sets aside that huge part of the planet as sort of a science preserve. And so collaboration among scientists is really important in a data limited system. And the realities of the geopolitics is that is going to stop. And you know, right now a lot of us are still trying to get out of the COVID pandemic where we haven’t been able to get into the field. And this will be another thing that will slow our understanding of the systems.

UMAIR IRFAN: Just a quick reminder that I’m Umair Irfan, and this is Science Friday from WNYC Studios. Today, I’m talking to polar researchers Uma Bhatt and Oscar Schofield about the changing Arctic and Antarctic regions and their future under climate change. We’ve got another question from an audience member, Nina from Baltimore. She has a question about carbon at the poles. Nina, if you’re there, would you mind unmuting yourself and asking your question?

NINA: Hi, I was wondering– how are permafrost dynamics affecting the overall shift from carbon sink to carbon source in the Arctic versus the Antarctic?

UMA BHATT: So as permafrost thaws, that’s going to release carbon. And there’s research going on about the timescale at which that’s happening. And at this point, that’s, again, debated by scientists exactly when that will happen, the timing of it.

OSCAR SCHOFIELD: For the Antarctic, because it’s been covered with ice for a long time, the land, we’re not so much focused on the permafrost, but what we are looking at, as the wind speed increases on the Southern Ocean, you get very vigorous mixing. And that has the potential to essentially decrease the amount of plankton growing, and essentially will make the Southern Ocean less of a carbon sink. But again, like Uma was pointing out, these are really hot topics among the scientists these days.

UMAIR IRFAN: And both of you, as experts in your respective fields who have been following these regions for decades, I wonder, is it hard to be a scientist, to be seeing these changes happening firsthand at such a fast pace? Do you feel sort of an emotional response to the science that you’re doing?

UMA BHATT: I think you do have an emotional reaction, because you’re worried. And there’s times that climate scientists feel hopeless. But I don’t feel hopeless because of young people. Young people have really kind of helped me. The students have really helped me take a more optimistic view that we’re going to figure this out, because we have a lot of the pieces in place in order to do that.

I think the other challenge is I feel like I’ve never achieved total knowledge. I’m just dumb, and I have to keep learning new things. And that’s actually a good thing, in that it’s such a complex system, and it continues to challenge me with new pieces that I need to learn about.

OSCAR SCHOFIELD: Yeah, I guess for myself, I have the same emotional reaction. My first trip down there was as I was graduating as an undergraduate. And the glacier behind the field station I worked at has retreated almost two football fields in my professional career. And so it is sort of shocking.

But my reaction is, my mission and my job is to make sure we have the most thorough understanding of this system so we can respond to it. And I try to keep focused on that mission rather than getting depressed. But having kids and everything, I worry about the planet they’re going to grow up on.

UMAIR IRFAN: And then finally, for both of you, looking ahead, what are some of the biggest uncertainties or unknowns that you think we need to start to resolve? Uma?

UMA BHATT: I think one of the uncertainties is how the different parts of the system interact with each other, how the changes in the surface water impacts the atmosphere. And it’s really increasing that interdisciplinary collaboration.

OSCAR SCHOFIELD: I would echo that. The system is incredibly complex. Where I work, if the atmosphere gets moisture, you get more snow and rain, which is counterintuitive. But that impacts the biology dramatically. A lot of the penguins have their eggs drown because they’re making nests in gullies to protect from the wind, not worried about water that they didn’t expect to have. And so there’s a lot of connections that are very complicated that we need to focus on.

UMAIR IRFAN: That’s all the time we have. I want to thank both of our guests for joining us today– Dr. Uma Bhatt, an atmospheric scientist at the University of Alaska Fairbanks, and Dr. Oscar Schofield, a biological oceanographer at Rutgers University in New Jersey. Thank you both very much for joining the show.

OSCAR SCHOFIELD: Thank you.

UMA BHATT: Thank you for having us.

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