Receding ice leaves Canada’s polar bears at critical risk

SPRAWLED on rocky ground far from sea ice, a lone Canadian polar bear sits under a dazzling sun, his white fur utterly useless as camouflage.

It’s mid-summer on the shores of Hudson Bay and life for the enormous male has been moving in slow motion, far from the prey that keeps him alive: seals. This is a critical time for the region’s polar bears.

Every year from late June when the bay ice disappears – shrinking until it dots the blue vastness like scattered confetti – they must move on to shore to begin a period of forced fasting.

But that period is lasting longer and longer as temperatures rise – putting them in danger’s way.

Once on solid ground, the bears typically have very few options for food, explains Geoff York, a biologist with Polar Bear International (PBI).

York, an American, spends several weeks each year in Churchill, a small town on the edge of the Arctic in the northern Canadian province of Manitoba. There he follows the fortunes of the endangered animals.

This is one of the best spots from which to study life on Hudson Bay, though transportation generally requires either an all-terrain vehicle adapted to the rugged tundra, or an inflatable boat for navigating the bay’s waters.

York invited an AFP team to join him on an expedition in early August.

Near the impressively large male bear lazing in the sun is a pile of fishbones – nowhere near enough to sustain this 3.5m, 600kg beast.

“There could be a beluga whale carcass they might be able to find, or a naive seal near shore, but generally they’re just fasting,” York says.

“They lose nearly a kilogramme of body weight every day that they’re on land.”

Climate warming is affecting the

Arctic three times as fast as other parts of the world – even four times, according to some recent studies. So sea ice, the habitat of the polar bear, is gradually disappearing.

A report published two years ago in the journal Nature Climate Change suggested that this trend could lead to the near-extinction of these majestic animals: 1 200 of them were counted on the western shores of Hudson Bay in the 1980s. Today the best estimate is 800.

Each summer, sea ice begins melting earlier and earlier, while the first hard freeze of winter comes later and later. Climate change thus threatens the polar bears’ very cycle of life.

They have fewer opportunities to build up their reserves of fat and calories before the period of summer scarcity.

The polar bear – technically known as Ursus maritimus – is a meticulous carnivore that feeds principally on the white fat that envelops and insulates a seal’s body.

But these days this superpredator of the Arctic sometimes has to feed on seaweed – as a mother and her baby were seen doing not far from the port of Churchill, the self-declared “Polar Bear Capital”.

If female bears go more than 117 days without adequate food, they struggle to nurse their young, said Steve Amstrup, an American who is PBI’s lead scientist. Males, he adds, can go 180 days.

As a result, births have declined, and it has become much rarer for a female to give birth to three cubs, once a common occurrence.

It is a whole ecosystem in decline, and one that 54-year-old York knows by heart after spending more than 20 years roaming the Arctic, first for the ecology organisation WWF and now for PBI.

“Here in Hudson Bay, polar bears are spending up to a month longer on shore than their parents or grandparents did,” York says.

As their physical condition declines, he says, their tolerance for risk rises, and “that might bring them into interaction with people, which can lead to conflict.”

The fate of the polar bear should alarm everyone, says Flavio Lehner, a climate scientist at Cornell University, because the Arctic is a good “barometer” of the planet’s health. |