Survival of the Fattest: The Effect of Shrinking Sea Ice on Polar Bears

polarOver the last month in the Canadian Arctic, around 1000 polar bears have gradually migrated to the coastal areas around Hudson Bay. After spending the summer on land, the bears are preparing for their return to sea ice.

The sea ice is critical to the bears’ survival. It “provides a vital platform to hunt ringed and bearded seal”, as well as other prey. This rich diet helps replenish the fat reserves of the world’s largest bears (weighing up to 1300 pounds). It ensures that after the ice melts, the bears can survive another lean summer on land.

But, like many animals, polar bears are falling victim to climate change. Since 1979, “sea ice cover has declined by about 30% in the Arctic”. Furthermore, the length of the sea ice season has fallen by approximately 30 days.

Consequently, “polar bears have been coming to land earlier and leaving later in recent years”. As the bears lose nearly 2 pounds/day on land, they are “60 pounds lighter on average than [polar bears] three decades ago”.  This weight loss has profound effects on the species. Lighter bears are not only less robust, they also produce smaller cubs “which can struggle to survive”. Hence, the polar bear population in Churchill, Manitoba (the “polar bear capital of the world”) has dropped by 22% since 1987. Without intervention, “two-thirds of all polar bears will be gone by 2050—and perhaps extinct in the wild by the end of the century.”

Unfortunately, polar bear conservation is no simple task. According to Polar Bears International, the traditional solution is to protect critical habitat, “but we can’t really build a fence to protect the sea ice from rising temperatures.” Nor can we simply wait for polar bears to re-adapt to life on land: “They can’t undo hundreds of thousands of years of evolution in 50 or 100 years.” Therefore, a better approach is to stem the rise of greenhouse gas emissions and, by extension, climate change.

This requires a concerted effort by many actors: governments, businesses, and individual citizens. To learn how you can combat climate change, please contact Clean Air Cool Planet. Also, to support threatened wildlife, please donate to the WWF or our partners, Motley Zoo Animal Rescue and Noah’s Ark.

Flickr photo credit: Staffan Widstrand

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