Polar bears are wasting away in a changing climate

Source: Nature

Polar bears have become the poster child for climate change, but their situation might be worse than researchers thought, according to a recent study. These Arctic mammals need a lot more calories than scientists previously estimated — but with sea ice melting under their feet, the bears often struggle to get enough to eat.

The study's results, published on 1 February in Science1, have captured the best picture yet of how much energy it takes to be a polar bear (Ursus maritimus) — and ecologists are looking to incorporate the findings into their own work on the Arctic. The study also supports scientists’ concerns that receding sea ice harms the bears by hindering their hunts of fat-rich seals.

If polar bears can’t meet their energy demands, their already declining populations could shrink by more than 30% over the next four decades, says Andrew Derocher, an ecologist at the University of Alberta in Edmonton, Canada. “This study is going to become the new hallmark for understanding polar bears’ ecology,” Derocher says.