Canada’s western Hudson Bay polar bear population has dropped 27% in just five years, according to a government report released this week on climate change’s impact on the animals.
Every fall, bears living along the western edge of the bay pass through the sub-Arctic tourist town of Churchill, Manitoba, as they return to the sea ice. This has made the population not only the best-studied group in the world, but also the most famous, worth $5.30 million annually to the local bear-watching economy.
However, Nunavut’s official assessment found that only 618 bears remained in 2021 – about 50% less than in the 1980s.
“In some ways, it’s completely shocking,” said John Whiteman, chief research scientist at the conservation nonprofit Polar Bears International. “What’s really alarming is that such a decline is predicted to lead to eventual…extinction unless sea ice loss is halted.”
Polar bears rely on sea ice for hunting, venting over seals’ breathing holes. But the Arctic is now warming nearly four times faster than the rest of the world. Around Hudson Bay, seasonal sea ice melts in early spring and forms later in the fall, forcing bears to go long periods without food.
Scientists caution that a direct link between population decline and sea ice loss in Hudson Bay is not yet clear, as four of the past five years have seen moderately good ice conditions. Instead, they said, climate-induced changes in local seal populations could reduce bear numbers.
And while it’s possible some bears may be on the move, “the number of adult male bears has stayed more or less the same. The decline is due to the decline in juvenile bears and mature females,” said Stephen Atkinson, an independent wildlife biologist who led research for the government.
This shift in population doesn’t fit with the idea that bears are moving out of western Hudson Bay, he added.
“In 2021, very few cubs were produced,” said Andrew Derocher, who leads the Polar Bear Science Lab at the University of Alberta. “We’re looking at a slowly aging population, and that’s when you get worse [ice] Over the years, older bears are more vulnerable to increased mortality.”
Also of concern to scientists, reports suggest that the decline has accelerated. Between 2011 and 2016, the population decreased by only 11%.
There are 19 populations of polar bears spread between Russia, Alaska, Norway, Greenland and Canada. But the western Hudson Bay is one of the southernmost locales, and scientists think the bears here are likely to disappear first.
A 2021 study in the journal Nature Climate Change found that most of the world’s polar bear populations are on track to collapse by 2100 unless greenhouse gas emissions are drastically curbed.