Polar Bears Could Be Extinct By 2100 Unless Action Is Taken On Climate, Study Says

As the Arctic sea ice declines, polar bears struggle to feed themselves.

One image of a starving, emaciated polar bear captured the world's attention for a while in 2017, and although some controversy surrounded the image, what hasn't changed is that the sea ice polar bears rely on for hunting continues to retreat.

The primary problem is energy use, which the researchers modeled to determine the limits of a polar bear's endurance.

"What we've shown is that, first, we'll lose the survival of cubs, so cubs will be born but the females won't have enough body fat to produce milk to bring them along through the ice-free season," Dr. Steven Armstrup, chief scientist with Polar Bear International, who was involved with the study, explained to the BBC.

"Any of us know that we can only go without food for so long. That's a biological reality for all species."

The World Wildlife Fund estimates their population to be between 22,000 and 31,000, but because of the remote areas they inhabit, it's hard to say for sure how many are left. They're spread out over 19 subpopulations around the Arctic Circle, from the Svalbard, Norway area to Canada's Hudson Bay to the Barents Sea in Russia.

The researchers cast doubt on the ability of any polar bears to adapt to life on land when sea ice disappears, noting that the bears moved north, away from land at the end of the last ice age.

"Foods that meet the energy demands of polar bears are largely unavailable on land," the study said.

In one, greenhouse gases were left undeterred and continued to rise at the current rate. In the other scenario, greenhouse gases were mitigated and warming was halted at half a degree above the Paris Agreement's ambitious targets.

Under the second scenario, the researchers predicted several subpopulations, including those around Hudson Bay, would disappear. If climate change is left unaddressed completely, all but one population will be gone.

"By 2100, recruitment," - in other words, births - "will be severely compromised or impossible everywhere except perhaps in the Queen Elizabeth Island subpopulation," Armstrup told CBS News.

And as Armstrup emphasizes, the study paints a far from worst-case scenario. "It’s important to highlight that these projections are probably on the conservative side," he told The Guardian. "The impacts we project are likely to occur more rapidly than the paper suggests."

"Even if we mitigate emissions, we are still going to see some subpopulations go extinct before the end of the century," added University of Toronto biologist Dr. Peter Molnar.

"The trajectory we're on now is not a good one, but if society gets its act together, we have time to save polar bears," Armstrup told the BBC. "And if we do, we will benefit the rest of life on Earth, including ourselves."

However, it's going to take some work. "My hope is that showing how grim and dire the situation really is will emphasize one more time how urgent the problem of dealing with climate change is," Molnar told the CBC. "We know what needs to be done."

h/t: BBC, The Guardian