This is a sound that’s well known to city dwellers, particularly Torontonians, but really anyone in southern Ontario, Quebec, or B.C., and especially on garbage day. Nope, the animal you’re hearing is not a raccoon. It’s actually a relative newcomer to Canada.

With its grizzled grey fur, beady black eyes popping out of its stark white face, and long, hairless, rat-like tail, it can be a bit of a shock to unsuspecting Canadians.  

Joshua Ostroff: So I'm in my backyard and a creature just kind of walked past. What I saw from behind, out of my peripheral vision, looked like a rat the size of a cat. They're enormous, like shockingly big.  

That’s Joshua Ostroff. He’s on the content team at WWF-Canada.

Joshua Ostroff: I guess my immediate reaction when I saw its face was relief that it wasn't a rat the size of a cat.

Virginia Possums, or opossums (both are correct), are North America’s only marsupial, but historically, they’ve always lived much farther south, in the Eastern United States and Mexico. However, since the 1950s, the Virginia Possum has been slowly moving north as milder winters caused by climate change expanded its range.  

Joshua Ostroff: If you like, I don't know if I realized it the first time, but their faces are really, really cute. It's really just the tail that's so disturbing.

As omnivorous scavengers with transient tendencies, possums are kind of the perfect inhabitant for cities, which provide plenty of access to food and shelter. A decade ago, there were around 350 possum sightings reported to Toronto animal control in a year. In 2024, that number had ballooned to over a thousand.

Joshua Ostroff: They eat ticks. They don't get rabies and they really don't have opposable thumbs or the ability to climb. So all the concerns that I have of the like raccoons that haunt my neighborhood all the time, I don't have those around the possums because they're really only kind of benefiting the neighborhood.

So far, they’ve spread to Southern Ontario, Southern Quebec, the Fraser Valley and Lower Mainland, BC.

Joshua Ostroff: My wife doesn't agree with me on how cute they are, but she's wrong.  

But possums aren’t the only species whose range is shifting because of climate change…

I’m Aliya Jasmine. I’m a wildlife filmmaker and environmental journalist. On this podcast, we’re meeting the incredible species that call Canada home, and the people working to protect them. From WWF-Canada, you’re listening to This Is Wild.

When possums make their way north, they're on the hunt for something called "climate refugia" - and lots of other species are on that same hunt, from lynx to moose to that most beloved Canadian megafauna, the polar bear.

Climate refugia are safe havens for plants and animals during major environmental shifts. They’re areas that can maintain stable conditions because of their physical features. Refugia can be local microclimates, like the top of a mountain that stays snowy in the middle of summer, but in the case of global climate change, latitude plays a huge part in determining which regions might help species escape the increasing heat.  

Brandon Laforest: Climate refugia are areas that under climate change scenarios will maintain their integrity relative to what we see today.

That’s Brandon Laforest; he’s a polar bear biologist and the Lead Specialist of Arctic Conservation for WWF-Canada.  He says that climate refugia can buy time for a species to adapt or simply wait out rapid environmental changes. Many species have survived wildfires, flooding, and even ice ages by seeking out refugia.  

Brandon Laforest: There are impacts that are going to be happening in the coming decades based on decisions that were made in the past and decisions that are made today. But climate refugia offer hope for species that are very dependent on particular environmental factors and features based on where they live now.  

Polar bears live in the circumpolar north at the very top of the globe. That includes Canada, Alaska, Russia, the Norwegian archipelago, and Greenland.  

Brandon Laforest: Actually two-thirds of the world's polar bears are found here in Canada, which gives us a unique responsibility for the conservation and management of polar bears globally.  

Although they are the largest bears in the world, the polar bear's Latin name, Ursus maritimus, means ‘sea bear’. They’re actually considered marine mammals because they spend so much of their lives on, in, and around the ocean. They even have partially webbed front paws to help them swim!

Brandon Laforest: We normally think of marine mammals all being below water, animals like whales or fish or seals that spend their time in the ocean itself. But if you think about it, when polar bears are out spending the vast majority of their time walking on sea ice. They're interacting and existing completely in the marine ecosystem.  

All the food that polar bears eat lives in the ocean: seals, walrus, and even beluga whales. But a seal can hold its breath underwater anywhere from 30 minutes to 2 hours depending on the species, whereas polar bears can only hold their breath for 1 to 3 minutes. To give them a fighting chance out on the open water, polar bears depend on sea ice to gain access to their food.

Brandon Laforest: Seals are dependent on sea ice for breeding, and polar bears are dependent on sea ice for accessing those seals. So it's all a complicated dynamic that is basically boiled down to the fact that polar bears need sea ice to access food, and they have a very difficult time doing so without it.

While most active in spring, during seal pupping season, polar bears are also out and about in winter, unlike most bears in Canada. But in the summer, how they spend their time depends entirely on where in the Arctic they live, because not all sea ice is the same. There are 20 subpopulations of polar bears across the globe, and each one is adapted to exist in a slightly different ecosystem.

Brandon Laforest: Broadly, sea ice can be seasonal, or it can be year-round polar bears are adapted either to a year-round sea ice scenario or a scenario that's seasonal, meaning that in summer there is no sea ice. In some cases, polar bears spend time on land when waiting for the sea ice to form and in other areas they can choose to stay on the ice during the period when sea ice is at its lowest. What we're seeing is even in those populations, bears having to abandon the sea ice and go to land simply because it's not strong enough and not capable of supporting them.

Polar bears who live in the southern edges of the Arctic are most affected by the cycle of the seasons.

Brandon Laforest: You will see them moving around. They might find a carcass that's interesting. You might find a rogue polar bear trying to chase down a caribou calf. You might have some polar bears trying to catch fish in rivers. But largely, they're spending their time waiting for the sea ice formation. When the sea ice forms, polar bears will go out onto the ice and use that platform to look for food, to look for mates, and spend the rest of their season out on the sea ice until it melts again and they're forced back on shore.  

Polar bears that have to come onto the shore in the summer lose around one kilogram of fat per day until they can go back to hunting when the sea ice starts re-forming in fall.

Brandon Laforest: They'll try to maximize their time on the sea ice and then eventually have to swim from the ice to the land.

Unfortunately, the freeze-up is happening increasingly later in the year, so polar bears are fasting up to a month longer than they used to.

Brandon Laforest: Where we see the biggest impacts of that are in young bears, so bears that aren't that experienced and aren't as effective hunters as the big, large males. The other place we see impact is in mother polar bears or polar bears that are pregnant. They require additional sustenance in order to maintain their pregnancy. If you have a mother who has dependent cubs with her, she's feeding one, two, sometimes three extra mouths compared to a solo polar bear. So the ability of that mother to access food and to provide for her family is stretched. The currency of the Arctic Marine environment is fat, and polar bears in particular have a very specialized digestive system that is extremely effective at digesting and storing fat. Polar bears simply don't have the same digestive tracts or evolutionary history of other bears in Canada or around the world. Grizzly bears, which are also brown bears, as well as black bears, are more omnivorous, polar bears are a true carnivore. They really are only adapted to a marine-based diet that is full of fat. So there aren't alternative food sources for polar bears. They really depend on these marine mammal fat-filled food sources like seals.  

While we may imagine it as a vast, empty expanse, sea ice is actually anything but.

Steven Lonsdale: So the sea ice it's varied, it's complex, and it's not, it's not uniform.  

That’s Steven Lonsdale; he was born and raised in Iqaluit, Nunavut. He’s also been working with the Qikiqtani Inuit Association for the past 12 years, focusing on protected area development and Inuit rights.

Steven Lonsdale: The sea ice, it's as varied as hills, mountains, and salt flats. If you look at any piece of land, it could be marshy, could be mountainous, it could be super flat, it can be really rough, it can be jagged, it can have cliffs. So if you think about it in that sense, sea ice has the same attributes. The sea ice just affects everything.  

It’s actually the foundation for the entire Arctic marine ecosystem. Here’s Brandon again.

Brandon Laforest:  On the bottom of the sea ice grows sea ice algae, which is the very basis of the food web that leads all the way up to polar bears eventually in the Arctic ecosystem.  

Unfortunately, we’re losing sea ice at an alarming rate. But what does that mean, exactly?

Clive Tesar: So there will always be ice in the wintertime. We're talking about the erosion of the amount of time that ice covers Arctic waters.  

That’s Clive Tesar. He’s a former communications lead for WWF’s Global Arctic Programme. He now works as a policy consultant for conservation, mostly in the Arctic.

Clive Tesar: So there's longer and longer periods when there's no sea ice in particular areas. And that's the important thing: it's that length of time because that's what changes the whole ecology. The other thing that changes it is whether it's multi-year ice or first-year ice. Multi-year ice has different properties and even different colonies of microorganisms around it.

Sea ice that can withstand the summer heat goes on to become multi-year ice. Here’s Steven again.

Steven Lonsdale: Spring comes around, the ice slowly starts to break up. So it doesn't all melt. It breaks up and then starts melting. But then some of the chunks are so big that they don't ever fully melt, so that ice has survived the summer and has gone into winter and has become multi-year ice, and it'll be frozen in. And then that piece of ice will possibly get a few more layers on it with compacting snow and the water touching it throughout the year and getting a little bit thicker, little bit thicker. And then because it's so big and compact, it again doesn't melt in that short summer season. And you can always tell multi-year ice due to the colour. Like, the colour is so much more deeper and vibrant, and like this deep blue, and the quality of ice is harder. It's so much harder.  

Scientists have been using satellites to track changes to Arctic ice since 1979.  

Clive Tesar: They're looking at the satellite images, but they're also looking at particularities of ice dynamics and of wind currents and water currents and those change over time as well. You've got the transpolar drift, you've got all of these different elements that are affecting where and when there is summer sea ice.

Fortunately, researchers have found that there is one region that’s expected to be the final stronghold of multiyear ice. On the very tip top of the globe, in the waters of the central Arctic Ocean, shared between Canada and Greenland, is a region called The Last Ice Area.  

Steven Lonsdale: I was a little bit nervous going there for the first time and it was at the height of winter where there's 24-hour darkness. And so, yeah, feeling this kind of nervous energy as soon as I arrived, it just kind of dissipated. It was just so beautiful, and all the people were just so welcoming. Even though it was dark you could see the mountains.

WWF coined the term “Last Ice Area” over a decade ago to help evoke the urgency with which it needs to be protected. Some Inuit refer to it as “Similijuaq," which means “place of the big ice”. Here’s Brandon, WWF-Canada’s Arctic specialist, again.

Brandon Laforest: It's an area that represents a refuge for ice-dependent species such as polar bear, beluga, narwhal, walrus, and species that depend on the Arctic ecosystem and depend on the ice as a platform, either for protection from predators, in some cases or for the predators themselves who depend on the ice for access to food.

The Last Ice Area, or “LIA,” was one of those climate refugia we talked about—a haven for wildlife to hide out from climate upheaval. Protecting it is a type of future-proofing for polar bears and many other ice-dependent species to withstand the effects of climate change.

‍Brandon Laforest: What makes it more resilient is the fact that it's so far north that it has its own climate conditions - it's literally at the top of the globe. There's no Arctic further north than that. As everything is warming, it's the one that's going to persist with ice as long as possible. It's interesting to think about in terms of the finality of it. There is nothing further north. There is no sea ice elsewhere. It does represent the last ice area as it says in its name.  

Clive Tesar: I like to think of it as a plan B. So plan A is, you know, stop the impacts of climate change on the Arctic. But we know that's difficult. We know that that's gonna take some time and it's gonna take still a lot of persuasion, maybe some technical adaptation to help in that process, but ultimately, we need to have a plan B. We need to say, okay, well, if this doesn't happen as fast as we'd hoped, what else can we do? So the last ice area was the plan B. It's to say, okay, there is an area where the summer sea ice is more likely to persist for longer. That might be enough to sustain the ecology of this dependent on sea ice.

The LIA is already home to about 25% of the world’s polar bears. Narwhals spend part of the year there. It’s also home to huge colonies of seabirds, and, perhaps most critical to the ecosystem, under-ice algae.

Clive Tesar: We're trying to preserve this region for ice-associated life. The life that ranges from micro-organisms up to little, I call them little shrimpy things, and the biologists get very upset with me. There are then Arctic cod of course that feed on those things and then there's seals and it goes all the way up to polar bears and increasingly killer whales as top predators. But also part of that system, if you look at it from an Indigenous worldview, are people. Right? So the Inuit are part of that system of ice-associated life. They're part of that life, they’re part of that whole ecosystem of life that's associated with ice and it has been for millennia.

Almost every community in Nunavut is coastal, so the sea ice plays a huge part in the day-to-day lives of the people that live there. People like Steven.

Steven Lonsdale: The ice is our highway, it's about access. It's about reaching hunting and fishing grounds. It's about going to various camping grounds that are passed on from our parents and grandparents, so you have the  multi-generational importance of certain areas, and these are where we make memories. And so these places are special, and they are really only accessed by sea ice. So having access to customs, having access to our places of wellbeing is extremely important. The travel on the ice is part of that experience. It's part of going out hunting and providing for your family but it's also like, it’s fun.  

Polar bears aren’t the only ones who have so much to lose when the sea ice melts; the Inuit, the people who’ve lived there since time immemorial, do too.  

Steven Lonsdale: In the pursuit of food, in the pursuit of practising customs and interacting with the land, you reach a point where you're like, I can't do this anymore, or I got to cut it short. And so that season that we're used to gets shorter and then we adjust and move elsewhere. And so when you lose that, you lose the opportunities to be able to pass on customs, to practise language to really experience nature for what it is because the basis for the traditional way of learning is to observe and to do.  

Big observable changes are already happening in the Arctic, as are some very small ones you might not expect. Here’s Clive again.

Clive Tesar: I remember actually a few years ago, somebody from Arctic Bay posting about robins; they'd never seen robins. So they're seeing new species. And they're also posting about things like, you know, gee, at this time last year, I was able to get out on the sea ice. It hasn't formed yet. I can't get out.

Just like the possums we talked about at the beginning of the episode, it seems that robins are also on the move. Actually, a study from 2009 found that more than half of the bird species in North America are spending the winter significantly farther north than they did 40 years earlier¹.

Clive Tesar: The Arctic is warming at a rate of about four times the global average. So you're seeing impacts there happen harder, you're seeing them happen faster. You're seeing changes in real time now. We're not projecting into the future. We're not saying, oh this might happen, or that might happen. It's happening.

The northernmost Inuit communities are some of the first to bear witness to these changes, which is one of the many reasons they need to be respected as caretakers of the Arctic. According to Steven, Inuit also have a very different way of looking at things than Western scientists.

Steven Lonsdale: When we speak about Inuit knowledge, or as we call it Inuit qaujimajatuqangit, which translated is, like, what Inuit know or what Inuit have always known, and it is directly linked to identity. So when you speak about things, it's through experience of your own. It's based on real-world applications. And so it is very practical and it's not so much based in theoretical knowledge. It's based on experience, both personal and passed down, and so it becomes kind of this mix of historical knowledge and current knowledge, as well as just people's opinions on things all balled into one. You speak to an experienced hunter, and they will differentiate between, you know, a smaller crack and a bigger crack even the different colours, the different textures, the time of year, and things like that, you know. I know the basics, but I can't hold a candle to some of these seasoned full-time hunters. They're in deep connection to that land that comes with that expertise. And unfortunately, looking at my generation, there's still guys my age that are of that caliber, but we are losing a lot of that kind of knowledge.  

WWF-Canada is working to support and protect the entire LIA, and to promote Inuit-led conservation and management of the area. Here’s Brandon again.

Brandon Laforest: What's impressive about the Last Ice Area is that it is just that. It's the last place where ice is going to persist. And it represents not only for Canada, but for the globe, a really important ecosystem that a lot of animals, that a lot of people, care about. It also represents a way of taking action in a world where you often feel paralyzed from an environmental perspective, especially from a global warming perspective of what are we going to do? How can we contribute? It's an opportunity to come together not only nationally but internationally as well, and in an area where no country has unique jurisdiction to protect something that is of global value.  

The Last Ice Area is a crucial place to protect. But so far, only a fraction of it has been, and some of those protections are only temporary.  

Clive Tesar: I think it buys us some time to get our act together, to ensure that we can do what we need to do to contain the impacts of climate change. But it doesn't buy us indefinite amounts of time.  

Even the Last Ice Area won’t last forever.  

Clive Tesar:  How long will it last? I can't tell you confidently. I can't say it's going to be 20 years or 50 years or 100 years. But it's likely to give us at least some time to be able to make the sorts of changes that we need to make so that summer sea ice can persist.

Thanks for joining us today on This Is Wild! I'm your host, Aliya Jasmine.

To learn more about WWF-Canada's initiatives to help protect the Last Ice Area, head to WWF dot CA slash this is wild.

And to learn more about everything going on at WWF-Canada, you can sign up for our newsletter, Living Planet News! The link is in the show notes.  

If you enjoyed this episode, please leave us a review on your favourite podcast app, and share the show with your friends. And if you have questions or suggestions, you can reach us at thisiswild@wwfcanada.org.

This Is Wild is created by WWF-Canada and Antica Productions.  

Our executive producers are Laura Regehr and Stuart Coxe. Our producer is Emily Morantz.

This episode was written by Andrea Varsany [VAR-sun-nee].  

Our production team at WWF-Canada is Joshua Ostroff, Erin Saunders, and Tina Knezevic [kuh-NEZ-ah-vick].  

Nicole MacAdam is WWF's SVP of Strategic Communications.  

Mixing and sound design by Philip Wilson.

‍

‍