Will Polar Bears Be A Victim Of Climate Change?

Terry Debruyne/USFWS

Whether or not you buy into climate change as a major concern, scientific research should at least be taken into consideration. Take this  Los Angeles Times piece on how polar bears burn calories how that could impact the species if there’s less ice.

Here’s more from Times reporter Amina Khan:

Scientists studying the metabolism of free-ranging polar bears in the Arctic have found out why the loss of sea ice is hurting their survival: They burn calories at a faster rate than previously thought.

The findings, described in the journal Science, reveal alarming facts about the polar bear’s unsustainable physiology in the face of ongoing climate change.

As human-produced greenhouse gas emissions continue to fuel global warming, the Arctic sea ice levels continue to shrink by about 13.2% per decade. At the same time, a number of polar bear populations have been on the decline —for example, dropping by about 40% in the Beaufort Sea in the course of a decade.

“We’ve documented declines in the population, declines in the abundance, declines in the survival rates, declines in the body condition in the population,” said lead author Anthony Pagano, a research wildlife biologist with the U.S. Geological Survey’s Anchorage, Alaska, office. “And it appears to be related to changes in sea ice that are occurring.”

But understanding the exact relationship between the loss of ice and the plight of the polar bear has been a little murky because it’s difficult to track the movements of these enormous apex predators in remote regions.

“What we don’t really know much about is, what are the actual mechanisms that are driving these declines?” said Pagano, who is also a PhD student at UC Santa Cruz. “We don’t have a lot of information about really the basic biology and natural history of these animals when they’re on the sea ice and how they utilize the sea ice environment.” …

Researchers found that the bears’ metabolic rates were an average of 1.6 times higher than scientists previously thought. That may be partly because the carnivores typically spend more energy than animals with herbivorous or mixed diets, pointed out John P. Whiteman of the University of New Mexico in Albuquerque, who was not involved in the study.

“The high energy requirements of polar bears corroborate previous hypotheses that most terrestrial Arctic habitats, lacking prey as energy-rich as marine mammals, cannot provide enough food for polar bears driven to shore by loss of sea ice,” Whiteman wrote in a commentary on the paper.

That loss of sea ice is a grave problem for polar bears, which rely on the fat-rich seals found in a sea-ice environment. Arctic land animals have very little caloric content compared with these marine mammals. Getting stuck on land simply wouldn’t keep these apex predators alive.




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