Polar bears are thriving despite loss of sea ice

As sea ice disappears in Norway’s Svalbard archipelago, the fastest warming place on Earth, polar bears have been getting fatter — but scientists don’t expect it to last.

The northern Barents Sea, which stretches between Svalbard and Russia ’ s Novaya Zemlya in the Arctic Ocean, has been heating up seven times faster than the globe as a whole.

The sea ice around Svalbard lasts two months less in winter and spring than it did two decades ago. Bears now have to swim 200 to 300 kilometres between hunting grounds on the ice and snow dens on the islands where they give birth.
But the average size and weight of the Svalbard bears have increased since 2000.

“We should think about this as good news for Svalbard,” says Jon Aars at the Norwegian Polar Institute.
Polars bears are split into 20 populations across the far north. While numbers are declining in parts of Alaska, Canada and Greenland, the Barents Sea population is thought to be stable or perhaps even growing.

Starting in 1995, Aars and his colleagues tranquilised 770 bears with dart guns, then measured their length and, to estimate weight, their girth at the chest. Trend analysis showed this body condition decreased until 2000, then increased until the end of observations in 2019.

In the spring, when ringed seals give birth to pups on the sea ice, polar bears hunt them to build up stores of fat for the ice-free months. Aars and his colleagues believe the shrinking ice area may be making these seals easier to find.
The approximately 250 bears that remain on the islands when the ice recedes may be hunting more harbour seals, which are spreading to Svalbard as the climate warms.

These “local bears” are ransacking duck and geese colonies for eggs, and have also been seen chasing down reindeer from a growing population.

However, “it will be very difficult to support a reasonable population of polar bears if sea ice disappears,” says Jouke Prop at the University of Groningen in the Netherlands.

“There will be a threshold, and... polar bears in Svalbard will be negatively affected by continued sea ice loss,” says Aars.

(Alec Luhn, New Scientist, 2026, distributed by Tribune Content Agency)