In Norway's Svalbard archipelago, the fastest-warming region on Earth, polar bears have surprisingly increased in size and weight since 2000, even as sea ice diminishes. Researchers attribute this to adaptive foraging behaviors amid shrinking ice. However, experts warn that long-term survival remains threatened by ongoing climate change.
The northern Barents Sea, encompassing Svalbard and Russia's Novaya Zemlya, is warming seven times faster than the global average. Sea ice around Svalbard now persists two months less during winter and spring compared to two decades ago, forcing polar bears to swim 200 to 300 kilometers between hunting areas on the ice and birthing dens on the islands. Despite these challenges, a study led by Jon Aars of the Norwegian Polar Institute reveals that the average body size and weight of these bears have risen since 2000, a trend that caught scientists off guard. From 1995 to 2019, the team tranquilized 770 bears via helicopter darts, measuring their length and chest girth to estimate weight. Analysis showed body condition declining until 2000, then improving through 2019. The Barents Sea population, estimated at 1,900 to 3,600 individuals two decades ago, appears stable or possibly growing. Polar bears, divided into 20 populations across the Arctic, face declines in areas like Alaska, Canada, and Greenland, while others remain stable; data is insufficient for nine groups. In spring, bears target ringed seal pups on sea ice to build fat reserves for ice-free periods. Researchers suggest that reduced ice extent might concentrate seals, making them easier to hunt. Island-dwelling bears, numbering around 250 when ice retreats, are turning to coastal bearded and harbour seals— the latter expanding northward due to warming—as well as bird eggs, reindeer, and walrus carcasses from a burgeoning population. Aars views this as temporary good news: “We should think about this as good news for Svalbard.” Yet, Jouke Prop of the University of Groningen describes the bears as “a species in despair,” resorting to unconventional feeding. The 1973 international ban on polar bear hunting for hides and zoos may mean populations haven't hit carrying capacity yet. Still, warming disrupts the ice-based food chain, from algae to seals. Prop cautions that supporting polar bears will prove difficult without sea ice, while Aars predicts: “There will be a threshold, and… polar bears in Svalbard will be negatively affected by continued sea ice loss.”