Polar bears may survive high up in the Arctic but Manitoba and Ontario's bears are all but doomed, says the world's best-known expert on the species.
Wildlife biologist Ian Stirling, who's been studying polar bears for 41 years, believes it is now too late to prevent the iconic Arctic species from being wiped out from the shores of Hudson Bay.
Increasingly long ice-free periods on the bay have led to less feeding on seals, lighter females, fewer births and more mortality among the southernmost subpopulations of polar bears, according to research conducted by Stirling, other biologists and climatologists over the past three decades.
"Things definitely don't look good for the Western Hudson Bay and Southern Hudson Bay populations," Stirling said in an interview.
"Long term, if we don't stop climate warming and the continued melt of sea ice, that population will disappear, maybe in 30 or 40 years," Stirling said. "We could keep parts of the northern ice area. We're not going to save Hudson Bay. It's too late for that, unless we could cool it down."
Stirling, an adjunct professor of biology at the University of Alberta, has devoted his life to the study of marine mammals. He's condensed some of his work into Polar Bears: The Natural History of a Threatened Species.
As Stirling and other biologists have documented, Hudson Bay sea ice now breaks up an average of three weeks earlier at Churchill, Man., than it did three decades before. Since polar bears consume almost all their calories on the ice, where they hunt for seals, this has led to fewer meals, declining weights, fewer births and more cannibalism among bears in the area, said Stirling, citing well-known research.
The average polar bear eats about 43 seals a year. Missing out on two or three of those meals is enough to cause a female polar bear to lose enough mass to give birth to underweight cubs or no cubs at all, said Stirling, noting the relationship between sea ice, feeding and fertility has profound implications for the survival of the species.