The polar bear population could become extinct by 2100 due to climate change, according to research published in the journal Nature. Polar bears are spread across 19 distinct sub-populations in Canada, Alaska, Siberia, Svalbard Island, and Greenland.
Their dwindling bodyweight undermines their chances of surviving Arctic winters without food. With temperatures warming twice as fast in the Arctic as the rest of the planet, the decrease of ice is becoming a problem. Unable to find other food as rich as seals in their surroundings means polar bears venture further and further from their territory.
“The bears face an even longer fasting period before the ice refreezes and they can head back out to feed.”
– Said Steven Amstrup, Chief scientist of Polar Bears International.
In the study, scientists estimated the maximum and minimum weight of the bears and modeled their energy expenses. They managed to calculate the maximum number of fasting days that a polar bear can endure before the survival rates of adults and children start to decline.
There are currently about 25,000 wild polar bears on Earth. Polar bears are the largest type of bear on the planet, with each weighing up to 1,600 pounds. That means, they need a lot of food in order to survive.
With the modeling data scientists combined those thresholds with the projected number of future sea ice-free days to determine how polar bear population will be affected in different parts of the Arctic.
“There is very little chance that polar bears would persist anywhere in the world, except perhaps in the very high Arctic in one small subpopulation, if greenhouse-gas emissions continue at so-called business-as-ussual levels.
– Said Peter K. Molnar, lead author of the study.
The research showed that a male bear, for example, in the West Hudson Bay population, is 20 percent below its normal body weight when fasting begins will only have enough stored energy to survive about 125 days rather than 200. Newborn cubs are even more exposed, according to the study, especially when mothers have not fattened up enough to provide nourishing milk.
The polar bear’s vulnerable status on the IUCN Red List of endangered species less severe that “endangered” or “critically endangered” does not accurately reflect their plight, the authors argued.
“Unlike other species threatened by hunting or deforestation, polar bears can only be saved if their habitat is protected, which requires tackling climate change at a global level. It’s important that the public undestand the urgency of the issue.”
– Said Steven Amstrup.
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The data reported by the specialists indicate that the polar bears would begin to have serious problems to survive from 2080. And by 2100, it looks inevitable that these populations will experience reproductive failures, leading to extinction if countries don’t drastically reduce emissions of heat-trapping gases.