The sea ice around Svalbard lasts two months less in winter and spring than it did two decades ago. Polar bears depend on sea ice for many aspects of their lives Trine Lise Sviggum Helgerud, Norsk PolarinstituttIn 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. Svalbard bears are better able to adapt than scientists expected, “so extinction is delayed”, says Jouke Prop at the University of Groningen in the Netherlands. “It will be very difficult to support a reasonable population of polar bears if sea ice disappears,” he says. “There will be a threshold, and… polar bears in Svalbard will be negatively affected by continued sea ice loss,” Aars says.