Science Vs - Polar Bears: A Surprising Tail

Episode Date: May 17, 2018

We have this idea that polar bears are teetering on the brink of extinction. But the story isn’t that simple. To find out why, we talk to environmental lawyer Kassie Siegel, wildlife biologist Dr. Karyn Rode, and sea ice expert Dr. Ignatius Rigor. With a little help from Payton, a polar bear at the Memphis Zoo. Check out the full transcript here: http://bit.ly/2qv9n1t Selected readings: This map of polar bear populations around the ArcticOn the Endangered Species Act and global warmingKaryn’s tale of two bear populationsThis paper on Arctic sea ice This episode was produced by Wendy Zukerman, senior producer Kaitlyn Sawrey, and Heather Rogers, will help from Rose Rimler, Shruti Ravindran, and Meryl Horn. Extra help from Saidu Tejan-Thomas. We’re edited by Blythe Terrell, extra editing help from Caitlin Kenney. Mix and sound design by Emma Munger. Music written by Bobby Lord and Emma Munger. Recording help from Peter Frick-Wright, Amber Cortes and Katy Sewall. A huge thanks to all of sea ice and polar bear researchers that we contacted for this story, including: Dr Walt Meier, Professor Kent Moore, Dr Ian Stirling, James Wilder, Anthony Pagano, and Dr Peter Boveng. And more thanks to Danielle Brigida, Frank Lopez, Gerald Thompson, the Zukerman Family and Joseph Lavelle Wilson. Learn more about your ad choices. Visit podcastchoices.com/adchoices

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Hello. Oh, my gosh. Why did I put on this voice? I'm Wendy Zuckerman, and you're listening to Science Versus from Gimlet Media. This is the show that pits facts against fluffy white bears. I'm at Memphis Zoo and zookeeper Kim Sanders is showing me my very first polar bear. He looks like a mythical creature.

Oh, I love that. They're so big and it takes your breath away, it takes your words away. Everything, that face you're having right now now I feel that every day with him. She's talking about Peyton a thousand pound polar bear and I'm at the back entrance of his enclosure where visitors don't usually get to go. This is where he sleeps and gets fed and although Peyton and I are separated by a thick steel mesh gate I'm allowed to get really close, close enough to feel his breath on my hand. Oh, my gosh, his head is, like,

maybe a hand span away from mine. Peyton is a healthy polar bear. He gets all the food he needs and he spends his days swimming and playing with toys. But away from zoos like this, we're not seeing images of happy polar bears like Peyton. In the wilds, we're told they're starving. Like, late last year, National Geographic released a video of an extremely skinny polar bear and it went viral. This music was playing as the desperate polar bear searched for food in rusted trash cans

and we were warned that this is what climate change looks like. The feeling is that if we don't act soon, polar bears will go extinct. And the last polar bears that we have will just be in zoos. Some people have different ideas, though. They think these claims are completely overblown. And it's really polar bear-izing. Without action on climate change,

say goodbye to the polar bears. It's totally false. So there's no question that polar bears are thriving. The predicted catastrophe failed to materialize. And a lot of people saying this stuff are climate change deniers, which makes me think, of course, that it must be nonsense. But when it comes to polar bears, they kind of have a point. Because get this, there are around 25,000 polar bears in the wild today. And as best as we can tell, over the last 10 years, their numbers haven't gone down. And even the World Wildlife Fund, the big hippies with the panda on their logo, they say that most of the polar bear populations are in healthy numbers. So on today's show, we're going to find out what is going on here.

Are polar bears going extinct or not? When it comes to polar bears, there's a lot of sad music. But then there's science. This week marks the 10th anniversary of the polar bears getting listed as threatened under the US Endangered Species Act. Ten years. So you might think that back then, their numbers were crashing. For the most part, though, they weren't.

So why were the polar bears listed as threatened? Why all the hot and bother about them back then? To find out, we had to speak to the lawyer who got the polar bears all this attention. I'm Cassie Siegel. I work at the Centre for Biological Diversity. Cassie is an environmental lawyer, and as you'd expect, she loves heading out into nature.

She used to raft through Alaska, where she told us that the water there is this... Beautiful turquoise blue, iconic blue colour, and just a beautiful wild place. And in the 1990s, Cassie wanted to save places like this from climate change, which the U.S. government wasn't really doing anything to stop. It's really frustrating, and it's really tough to see all of the missed opportunities. Being an environmental lawyer, Cassie thought,

what can I do to help? We wanted to force the government to start addressing climate change. But how? Well, Cassie and her team took a good look at the U.S. Endangered Species Act, and they thought they could use it in a kind of cheeky way to get action on climate change.

You see, it has a particular clause in it that says if a species is officially recognised as endangered, the government is required to do something to protect it. So Cassie and her team start thinking, what if they find an animal that was going to go extinct just because of climate change? Then the only way the government could protect that animal was to try to stop climate change. Exactly. Exactly. And Cassie knew that to get the government to list an animal as endangered because of climate change,

you need more than lawyers and loopholes. You needed to get the public fired up about saving a beautiful and desperate animal. So, here's what Cassie needed. A beautiful and desperate animal that would go extinct because of climate change. And the right animal was obvious. The Glacier Bay wolf spider. The what? It's a wolf spider. It's kind of obscure. I'm going to Google image this. Wolf spider, you say. Holy crap, it's really scary looking. It's a really scary looking... I come from Australia, like, I don't, like, I'm not squeamish about spiders, but, like, this is, like...

If you want a visual on the Glacier Bay wolf spider, it's like the love child between a wolf and a tarantula. I love the Glacier Bay wolf spider. I love its charming, hairy little legs. But it was kind of obvious to us that it wasn't going to be an icon of climate change. No, no one was going to rally behind a creature that could give your kids nightmares. So Cassie and her team found another contender. Surely this time they'd hit upon a really iconic animal. It's a seabird called the Kitlitz's muralette. It's related to the better-known marbled muralette.

And the Kitlitz, if we were going to describe it, I would say it looks like a pigeon that a bunch of birds have shat on. It's a gorgeous, gorgeous little seabird, kind of a mottled grey. Okay, so it's a step up from the wolf spider, but seriously, no one was going to give a crap about a crappy looking bird. Cassie needed something more charismatic. Then, in the early 2000s, she saw a study showing that climate change was threatening a big, beautiful creature that everyone

with a pulsing heart gives a crap about. Polar bears. The study didn't say that their numbers all through the Arctic were crashing right now, but it did say that this was likely to happen in the future, thanks to climate change. And here's why. Scientists were predicting that sea ice would drastically shrink because of climate change. And it's said that the polar bears need sea ice. So no sea ice, no polar bears. Cassie set to work petitioning the U.S. government to list polar bears as endangered. And even now, as she told my producer, Heather Rogers, and me about that time. She got really excited.

It was great. And I could read those papers and write that petition 12 or 15 hours a day. It was great. Often sitting at the dining room table in my polar bear slippers. No, you wore polar bear slippers? I did. Nothing more motivating than polar bears. So, in her polar bear slippers,

Cassie filed her petition on the 16th of February in 2005. It was late, just after midnight. She sent out a bunch of press releases and went to sleep. And when she woke up, the story had blown up. It was right on the front page of MSNBC. And there was a big picture of a polar bear. It was a great, great moment. Over the next few years, all the major US newspapers

published articles about how the polar bears were being threatened by climate change. And in 2006, a Time magazine cover featured a photo of a forlorn polar bear adrift on melting ice with the headline Global Warming. Be worried. Be very worried. The polar

bear was now an official icon of climate change and school kids started sending letters to Congress begging them to support Cassie's petition. It's amazing how many classrooms did that. And in 2008, the polar bear was listed as a threatened species, which meant it was likely to become endangered soon.

Yeah, I said, hey, it worked. It worked. But I'd not, it's hard to get, with these kinds of things, it's hard to get to sound too excited. So I was very, very glad that polar bears got the attention, but in order to make it mean something, we have to actually solve the problem, and we haven't done that. Cassie did this whole thing to get the US government

to protect the world from climate change. And over the years, her cheeky plan obviously wasn't enough. These days, it's looking grimmer than ever. We're going to put the miners back to work. We're going to get those mines open. And maybe it isn't surprising that the Endangered Species Act wasn't enough to force the US government to radically change its energy system. But still, it was a nice try. So, we know that when Cassie started this campaign more than 10 years ago, polar bears weren't dying off in droves.

The main reason the bears were listed as threatened was because of what could happen in the future. And guess what? We're in the future. And guess what? We're in the future now. So, what is happening today? Well, over the last decade, as scientists predicted, the Arctic has lost a ton of sea ice, millions of square kilometres of the stuff.

But what's happening with the polar bears right now is more complicated. To understand what's happening, we spoke to polar bear researcher, Karen Rode, from the US Geological Survey. And she is someone who gets very close to her research subjects. You know, they have really thick fur and they're very warm. What does their breath smell like? I mean, if they've just recently eaten seal, then they do smell like seal,

which is sort of a fishy marine smell. But otherwise, you know, I suppose it's a bit like dog breath. To get that close to them, Karen does some pretty adventurous science. She shoots polar bears with a tranquilizer gun from a helicopter. We use the helicopter to fly along the tracks because the bears have traveled so far that we would never catch up with them walking. She weighs, measures and takes blood samples from the bears. And things, she says, can get pretty slippery when you're trying

to study an unconscious bear. So we're all sliding. It's like having a thousand pound animal on an ice skating rink. And while doing all this slipping and sliding, Karen found that the bears in this part of the Arctic were, for the most part, healthy. In fact, she found huge, fat polar bears that were more than 1,300 pounds. Those are some of the largest bears that have ever been weighed anywhere in the world. And Karen saw mama bears with healthy baby triplets, which is pretty rare. Karen compared the data she got with figures from the 1980s, and she says that these days, these group of bears look good.

You know, we're not cautious about saying that the evidence right now is that that population is stable. But before you return your CD of sad polar bear music, Karen told us about a group of bears that are not doing so well. And they're right next door to the fatties. These other bears are in an area called the Southern Beaufort Sea. And the situation for some of those bears, it's pretty bad. And we found that in the Beaufort Sea, 42% of females had not eaten anything in the past seven to 10 days. Almost half of the female bears that Karen studied hadn't eaten in the past week.

And this was during a time when some of them really needed to be eating a lot because they'd just come out of this polar bear version of hibernation that only the new mums do. And they will lose hundreds of pounds in body mass. So it's particularly important that those bears, when they come out of the den in the springtime, would be gaining weight and recovering what they lost. So this was a time when these polar bears should have been gaining weight and instead they were losing weight. That's right.

And that, to me, was really striking. And this contrast with some bears doing well and others not is happening across the Arctic. So how is this possible? How are some bears fat and happy and others not so much? Well, Karen told us that if you really want to understand what's happening here, you have to know how the bears catch their dinner. Seals.

Yes, this is the real sound of a bearded seal. The tricky thing is that seals are faster swimmers than polar bears, so the bears can't chase them down in the water. Instead, to catch the seals, the bears sit on the sea ice, waiting for them to pop up for air. They wait and wait and wait. And then when a seal pops out, they pounce. Bottom line, polar bears need two things to be able to feed. They need the ice to access the seals and they need the seals. And as we mentioned, the Arctic has lost a lot of sea ice. So you'd expect that all polar bears across the Arctic

would be in trouble right now because how are they going to catch their seals? Well, the thing is that some bears, like those fatties, they're still catching seals. And here's why. Bearded seals love swimming in shallow water. And that's because they eat things on the ocean floor. And where the fat bears live,

it's shallow over a really large area. And so even though there's less ice around, the ice that's there is still covering parts of that shallow water. This means the fatties still have a lot of seals to pounce on from the ice. As for the bears not doing so well, the ones in the southern Beauford Sea, well, they are not so lucky. The sea ice in their area tends to sit in water that's really deep. And since those seals like shallow water, that means they're not around the ice.

Okay, so to wrap this in a big polar bear bow, where the fat bears live, the remaining ice is still near the bearded seals. Where the skinnier bears are, the seals, they're not around the ice so much. There are other things going on in this area too. I think what it tells us is that it is not just the sea ice alone that determines what the population status is going to be. That they can lose sea ice, some amount of sea ice in some places and maintain access to prey. And when you look at polar bears across the Arctic, there are lots of small differences that are kind of like this that help explain how well the bears are doing, even though there's less sea ice around.

And you might be thinking, well, if the ice is melting, why don't they just eat what's on land? Well, they are. Like, even where the fat bears live, Karen is noticing that more bears are coming onto land more often to look for food. They'll eat kind of anything that's around. Kelp, bird eggs, berries, caribou, muskox, fish.

But the problem for the polar bears is that Karen says this kind of food, for the most part, isn't enough to fill them up. And that's because they need a lot of fat. Polar bears have the highest fat diet of any species in the world. Yeah. Over thousands of years, polar bears evolved to basically be on a keto diet. And that land food just isn't fatty enough. But the seals are.

They're basically just big blubber balls. So polar bears, they probably need the seals. And to catch them, they use the ice. Karen is worried that if more and more ice melts, even the populations that look good now will eventually starve. So our final question is how long will the sea ice last? Will the polar bear go extinct? That's coming up after the break. Welcome back. So here's where we are.

Polar bears rely on sea ice to hunt seals, and we've lost a bunch of sea ice in the Arctic. But some polar bears are doing fine at the moment because they still have lots of seals swimming around the remaining sea ice. In the future, though, scientists around the world expect that because of climate change, we will lose more and more sea ice. And if that happens, it won't matter how many seals there are. If there's no sea ice, the bears struggle to catch them,

and many could starve. So, how long will the sea ice last? For this, we have to get a sea ice guy. Okay, hello. This is Ignatius Rigger. Ignatius Rigger. Doesn't he just sound like an Arctic explorer? He's from the University of Washington in Seattle

and still remembers heading out to the Arctic as a young researcher. Being the first time I saw sea ice, all the different shapes and patterns in the sea ice was pretty amazing. You know, 20, 30 years later, how long have I been doing this? I still find myself staring out the window, and, you know, it's pretty amazing. And over the decades, as he looks out that window, he's seen the ice change. Like he says, in parts of the Arctic, it's gotten so much thinner. And what will happen in the future?

Well, Eke told us that to find out, scientists look gotten so much thinner. And what will happen in the future? Well, Eke told us that to find out, scientists look into a crystal ball. No, obviously they don't do that. Instead, they have these very sophisticated computer models that are simulations of all the major things that affect sea ice, like heat coming in from the sun, greenhouse gases trapping that heat, heat melting the ice, the thinner ice melting faster. So you have all these factors that make a difference. And as you can imagine by now, sea ice melts in a really complicated way. Like, take the winds and the currents.

They can move the ice around, which then affects how the ice melts. Yeah, the sea ice isn't just sitting there anchored in place. It's getting blown about. It's pretty amazing what the wind and ocean currents could do, even on, you know, what may seem like a big chunk of ice. Ig says sometimes you can even hear it moving. Normally it's so quiet because there's nothing else happening out there, you know, but when the ice is moving and it's a windy day, it's, you know, there's a background din of crunching going on. This is actually what it can sound like. And here's why this moving ice is so important. Because where the currents and the winds push the ice plays a really important role in the polar bear's fate.

Like, in a part of the Arctic, the ice can get pushed around and literally be pushed out of the Arctic, out into warmer parts of the ocean where it melts easier. And Ig says that over the past few decades, likely because of climate change, more and more ice is being pushed out of the Arctic and melting. A lot of the older, thicker sea ice just got flushed out of the Arctic pretty quick. And when models try to predict the polar bear's future, they also have to consider that the Arctic isn't melting at the same rate everywhere.

Like up in the far north of Canada, Greenland, which is just nearby, has a tonne of ice that acts kind of like a huge freezer that helps cool that part of the Arctic. Which is all to say that predicting sea ice in the future and whether the polar bears might hang on is really, really tricky. But let's give it a go. Ig looked at a map of where polar bears might hang on is really, really tricky. But let's give it a go. Ig looked at a map of where polar bears live right now. Let's see, places. And he told us that according to the models,

the ice is going to really shrink in a lot of the places where polar bears currently live. You know, 30, 50 years from now, I think once the ice starts going away, then we're going to start to see the changes in these other populations also. Two different research groups with two different computer models have both predicted that by 2050, some areas of the Arctic, which now host thousands of polar bears, may have too little ice to keep those bears alive. That's around 30 years away. And then if we go further into the future, to the end of the century, what happens then?

So if I was a polar bear and I was going to decide where to buy a house, I would buy a house north of Canada. And then I'd hope that the humans, you know, pull their heads out of their orifices and, you know, shift gears. So why would you put your polar bear house there? Because that's the last spot that I would expect sea ice to be. Ig says that by the end of the century, there will probably still be enough ice for polar bears in just a few places up north of Canada and around Greenland. And once they're squished into those places,

scientists are concerned that over the years, their populations will get so small that they hit a point of no return. That is, no more polar bears in the wild. But we really don't know when or if that might happen. The loss of the sea ice has a pretty profound effect on whether they can survive or not as a species. And if there is no sea ice, what do you think would happen to the polar bears? Well, I... Am I allowed to use the word toast?

You are allowed to use the word toast. You can also put a swear word in front of it if you want to be naughty. No. So, are polar bears on the verge of extinction? For now, some populations are holding up, despite losing so much sea ice, which is a bit of a pleasant surprise. So some of those climate change deniers

are technically right on this point. But they're unlikely to be right for much longer because polar bears need sea ice, and the sea ice is disappearing. From the science we have now, it really is possible that for the young kiddies listening, you might be alive to hear news of the last wild polar bear. It seems likely they won't claw their way out of this one.

And if we keep losing large chunks of sea ice in the Arctic, we'll have more to worry about than just the polar bears. I mean, what about the Glacier Bay wolf spider? With its charming, hairy little legs? That's Science vs Polar Bears. To read more about the polar bears and see our transcript with all of our citations, sign up to our newsletter. Head to gimletmedia.com slash newsletter and click Science vs.

This episode was produced by me, Wendy Zuckerman, our senior producer, Caitlin Sori, and Heather Rogers, with help from Rose Wimler, Shruti Ravindran, and Meryl Horn. Extra help from Saeed Tajan Thomas. We're edited by Blythe Terrell. Extra editing help from Caitlin Kenney. Mix and sound design by Emma Munger. Music written by Bobby Lord and Emma Munger.

Recording help from Peter Frick-Wright, Amber Cortez and Katie Sewell. A huge thanks to all of the sea ice and polar bear researchers that we contacted for this story, including Dr. Walt Meyer, Professor Kent Moore, Dr. Ian Sterling, James Wilder, Anthony Pagano, and Dr. Peter Boving. Thanks to Danielle Bregada, Frank Lopez, Gerald Thompson, the Zuckerman family, and Joseph Lavelle Wilson. Next week, we look at the little-known story of how an American scientist influenced Hitler. People were sterilized. People were killed with this as part of their justification. I'm Wendy Zuckerman. Back to you next time.

So where is the softest part of the effort? The softest part of them is behind their ears. That part is as fluffy and soft as you want their whole bodies to be.