Sunday, December 1, 2013

Climate Change Affects Hudson Bay Polar Bear Population

The seasonal ice freeze in Hudson Bay is underway, which makes it time for the regular migration polar bears make to the coastal areas of Churchil, Manitoba.

Ursus maritimus, the largest bear in the world and the apex predator in the Arctic, relies heavily on sea ice for survival. These patches of frozen seawater serve as a crucial platform for the bears to hunt for ringed and bearded seals.
During the summer, when the ice melts for several months, polar bears go inland, conserving their energy in what’s known as a ‘walking hibernation; state. This was the cycle for hundreds of years, but serious changes are affecting polar bears, particularly the populations that regular come to Hudson Bay.

Research for the past 40 years shows sea ice cover in the Arctic declined by as much as 30 percent since 1979. According to Steven Armstupf of Polar Bears International, as greenhouse gases continue to reach ocean temperatures, polar bears are finding themselves staying longer on land.

For instance, the Hudson Bay polar bear population now spends an average of close to 30 days longer than they did three decades ago. That means the bears end up losing more weight, about 2 pounds, according to research, for each day they spend on land, and are therefore lighter by 60 pounds than they were 30 years ago.

This drop in weight also means polar bears are giving birth to smaller cubs, which can lead to problems surviving in the wild.  It’s theorized that polar bears ‘will be the first to go’ in a warming world, since depend on a habitat that melts once temperatures rise. If nothing changes, these animals could go extinct in the wild by 2050.

Read the full story on National Geographic.

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