Polar bears and climate change: New research in Norway has scientists baffled

Polar bears became the poster child for the peril of climate change for obvious reasons: They hunt seals from the ice, and as fossil fuels warm the planet, the ice where these bears live is melting.

For more than three decades, scientists have been warning that climate change could drive polar bear populations extinct. That message infiltrated the public psyche, perhaps more than any other about the scourge of global warming.

But as scientists are continuing to learn, the reality for these iconic bears is more complicated.

In 2022, scientists published a study showing that polar bears in southeastern Greenland were able to use glacial ice instead of sea ice to hunt, sheltering them from some of the impacts of warming. And a study published late last year revealed some changes in polar bear DNA that may help them adapt to hotter weather.

Now, research in the journal Scientific Reports adds yet another wrinkle of hope for the species. The study, an analysis of hundreds of polar bears in the Norwegian archipelago of Svalbard, found that declining sea ice is not causing polar bears to starve. They actually appeared healthier in the last two decades of the analysis, from 2000 to 2019. The overall population, meanwhile, is either stable or growing, according to Jon Aars, the study’s lead author and a scientist at the Norwegian Polar Institute.

“I was surprised,” Aars told Vox from Svalbard. “I would have predicted that body condition would decline. We see the opposite.”

The new study makes clear that, in other regions, the loss of sea ice from warming is indeed linked to ailing polar bear populations. In Canada’s Western Hudson Bay, for example, researchers have tied melting ice to lower bear survival and a shortage of food, finding that the population has roughly halved since the 1980s. Climate change remains the largest threat to these animals.

Yet, there are 20 distinct polar bear populations around the world, and they all behave slightly differently. Warming is not uniformly killing them.

Perhaps, then, polar bears aren’t the best mascot for the climate crisis — a point some advocates have been making for a while — especially when there are countless other species imperiled by rising temperatures.

What this new study says about polar bears

Polar bears need fat to survive the harsh Arctic cold; that’s why they eat blubbery seals. Seals, meanwhile, need ice to rest and birth pups. Without that ice, polar bears have a hard time finding and catching them.

Since the late 1970s, the Arctic — the northernmost region of the planet, including parts of Alaska, Canada, Europe, and Russia — has lost more than 27,000 square miles of summer ice. That’s an area larger than the state of West Virginia. Some estimates suggest that the region could be ice-free by the middle of the century, even under optimistic emissions scenarios.

That melting ice is what’s harming polar bear populations in Canada’s Hudson Bay; the Beaufort Sea, located north of Alaska and the Yukon; and Baffin Bay in Greenland. And it’s why they’re listed as threatened under the US Endangered Species Act and the International Union for Conservation of Nature and Natural Resources, a global authority on endangered species.

But the story in Svalbard — an icy archipelago in the Barents Sea, north of Scandinavia — is different.

Between 1992 and 2019, scientists in Svalbard darted hundreds of polar bears from helicopters and measured their bodies. Then they compared those measurements to sea ice conditions, such as the number of ice-free days, and other climate variables.

Remarkably, the number of days with no ice in the region increased by roughly 100 during that period. And yet, as the authors found, the body condition of both male and female polar bears — i.e., how fat and healthy they are — increased from 2000 onward. Female bears were actually in worse condition when the sea ice lasted longer.

Often, the message about polar bears is “100 percent doom,” said Kristin Laidre, a polar bear researcher at the University of Washington, who was not involved in the study. “But that’s not true,” Laidre told me. “There’s variability in how bears are responding. This [research] adds to the variability story.”

How are these bears surviving?

If polar bears in Svalbard are healthy, that means they’re finding food. So what are they eating?

One possibility, said Aars, the lead author, is that there may be higher densities of ringed seals, their primary food source, in years with less ice, so they’re easier to catch. Even if polar bears have less time to catch the seals — because there are fewer days with ice — they can put on loads of weight quickly and rely on that for months.

The bears may also be eating other animals on land that don’t require ice. Reindeer on the archipelago are increasing, for example, and Aars says he’s seen bears eat them. Walrus populations are increasing, too. Although polar bears can’t easily kill a walrus, they can scavenge their tusked, fat-filled carcass when walruses die from other causes.

“Bears in Svalbard are potentially changing their diet, and that might account for the increase in body condition,” said John Iacozza, a senior instructor and polar bear expert at the University of Manitoba. That’s a luxury that polar bears elsewhere might not have. “You wouldn’t see the same effect happening in Western Hudson Bay, just because the availability of other species is less,” said Iacozza, who was not involved in the new research.

While the Svalbard bears might be fine for now, researchers still worry about the long-term impacts of warming in the region. “We do think there’s a threshold,” Aars told me. “The difficult part is that we don’t know what it is.”

Does the climate movement need a new mascot?

No other animal has been so closely tied to climate change as the polar bear. It was on the cover of TIME’s 2006 global warming issue. It was featured in Al Gore’s seminal documentary An Inconvenient Truth, which premiered the same year. It was used in funding campaigns for environmental groups. (One year, I even dressed up as a drowning polar bear for Halloween with a friend who went as a melting ice cap.)

The bear’s symbolism is rooted in good science. Those early studies were in places like Canada’s Western Hudson Bay, where these Arctic apex predators were clearly dying from melting sea ice. Media outlets amplified the most sensational conclusions — and they stuck.

That’s partly because the message is simple, Laidre said: Polar bears need ice, and warming is making it disappear. “The relationship between [climate and] an animal that needs a platform to eat is easy to wrap your brain around,” she said.

Even before these more recent studies, the climate movement had moved away from using polar bears as a mascot for advocacy, journalist Kate Yoder wrote on the environmental news site Grist. Climate advocates worried that spotlighting the bears made global warming seem like a faraway problem — one for animals in remote regions, not a crisis for species and humans everywhere, right now. Today, messaging tends to focus on the very real human impact and the emotions that come with it: homes engulfed in flames or swept away by floods, for example, or extreme hurricanes barreling towards the coast.

From a scientific perspective, the polar bear still works as a symbol for the climate crisis, Iacozza said; these animals still need ice, so they’re still under siege from warming.

But if advocates did want a new mascot, there’d be a long list of other animals to choose from. All kinds of corals, for example, are getting cooked by marine heat waves. Rare Hawaiian birds known as honeycreepers are going extinct from avian malaria, which mosquitoes are spreading further uphill as the islands warm.

Other Arctic animals are threatened, too, Aars said, including ringed seals. “Many of those are more at risk than polar bears,” he told me. “There are also changes in Svalbard, in the sea, that are much more profound than what we see on land with polar bears. But people don’t see it, or people don’t care.”

Ultimately, it’s easy for people to care about polar bears. They’re big, they’re fluffy, and they’re unique. So perhaps, instead of ditching them as a mascot for warming, it’d be better to acknowledge that the story is more complicated than it’s often presented. Climate change impacts the natural world differently in different places.