written for The Day
Mystic—The top polar bear expert in North America told an audience of scientists that global warming is hurting polar bears in western Hudson Bay.
The 1,000-pound bears rely on a window of several weeks in the early spring to lumber across the ice and kill seals. This is their major gorge of the year, said Dr. Ian Stirling, a research scientist for the Canadian Wildlife Service.
In the last decade the ice has begun to melt earlier, leaving the bears less time to eat. Over the last 40 years the temperature has risen steadily in this part of the Arctic, suggesting that polar bears could begin to struggle to survive. They also could begin to visit human settlements to try to find food, he said.
Stirling spoke at a symposium hosted by Mystic Aquarium and its parent organization, Sea Research Foundation. “Arctic Seas: Currents of Change” brought together dozens of Arctic scientists this week to share research.
Stirling taught many of today’s polar bear researchers, said David St. Aubin, the aquarium’s director of research.
A new study of world temperature trends since 1950 shows that in the western end of Hudson Bay the average temperature has increased steadily, by about 1.2 degrees Celsius over four decades, Stirling noted.
Scientists have found over the last 20 years that polar bears always return to the land about three weeks after half of the ice melts. “It’s always that way,” Stirling said, “no matter when the breakup is.”
As long as there’s ice, the bears stay out on it, killing and eating seals.
So far, the number of polar bears hasn’t changed noticeably, Stirling said, but they are less healthy than they used to be. Polar bears can fast for a long time when there isn’t food, but eventually less of it each year is going to affect how many of them can eat in the wild.
They’re going to progressively become more of a threat to humans as they come into dumps looking for food, Stirling said.
“It’s going to be a very serious situation in many of the coastal settlements,” he said.
While polar bears prefer to eat ringed seals, they will eat other animals, too, including humans. Even when they’re at their thinnest and hungriest, they still weigh hundreds of pounds.
One female bear Stirling has observed over several years weighed 200 pounds one autumn, and then the next spring after gorging, she was up to 800 pounds and later gave birth to triplets. The fluctuation in weight is typical, he said.
But at some point, the bears won’t be able to eat for long enough to gain the weight they need to give birth to healthy babies. “We could in Hudson Bay see an average of 2 to 6 degrees (Celsius) over the next 55 to 100 years,” he said. He said an increase of 1 degree could result in the ice melting two weeks early.
“They’re extraordinarily sensitive to these kinds of things,” Stirling said.
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About This Article
The United Nations proclaimed 1998 the International Year of the Ocean. Mystic Aquarium hosted a four-day Arctic research symposium. It was here where I heard for the first time the effect of a changing climate on animals that depend on specific habitats like Arctic ice to survive. I made a big pitch at the newsroom to place this story on the front page, but the editors ran it on the back page of the news section on October 23, 1998. Here were top international researchers making dire predictions they had not shared widely in public before. I had not convinced my bosses that this would become an important story. Today, I look back on this and feel somehow that this was one time I was thinking clearly but not speaking loudly enough.