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Polar bears will be wiped out by the end of the century unless more is done to tackle climate change, a study predicts. Scientists say some populations have already reached their survival limits as the Arctic sea ice shrinks. The carnivores rely on the sea ice of the Arctic Ocean to hunt for seals. As the ice breaks up, the animals are forced to roam for long distances or on to shore, where they struggle to find food and feed their babies.
Polar bears are listed as vulnerable to extinction by the International Union for Conservation of Nature (IUCN), with climate change a key factor in their decline. Studies show that declining sea ice is likely to decrease polar bear numbers, perhaps substantially. The new study, published in Nature Climate Change, puts a timeline on when that might happen.
By modelling the energy use of polar bears, the researchers were able to calculate their endurance limits. Dr Steven Amstrup, chief scientist of Polar Bears International, who was also involved in the study, told BBC News: “What we’ve shown is that, first, we’ll lose the survival of babies, so babies will be born but the females won’t have enough body fat to produce milk to bring them along through the ice-free season.
The researchers were also able to predict when these limits will be reached in different parts of the Arctic. This may have already happened in some areas where polar bears live, they said. Under a high greenhouse gas emissions scenario, it’s likely that all but a few polar bear populations will collapse by 2100, the study found. And even if moderate emissions reduction targets are achieved, several populations will disappear.
(www.bbc.com, 20.07.2020. Adaptado.)
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