Most polar bears to disappear by 2100, study predicts

https://www.theguardian.com/environment/2020/jul/20/most-polar-bears-to-disappear-by-2100-study-predicts-aoe


Gloria Dickie
Mon 20 Jul 2020 11.00 EDT

Scientists have predicted for the first time when, where and how polar bears are likely to disappear, warning that if greenhouse gas emissions stay on their current trajectory all but a few polar bear populations in the Arctic will probably be gone by 2100.

By as early as 2040, it is very likely that many polar bears will begin to experience reproductive failure, leading to local extinctions, according to a study published in Nature Climate Change.

The study examines how the bears will be affected under two different greenhouse gas emissions scenarios. The researchers found that under a business-as-usual emissions scenario, polar bears will likely probably only remain in the Queen Elizabeth Islands – the northernmost cluster in Canada’s Arctic archipelago – at the end of the century. And even if greenhouse gases are moderately mitigated, it is still likely that the majority of polar bear populations in the Arctic will experience reproductive failure by 2080.

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“It’s important to highlight that these projections are probably on the conservative side,” said Steven Amstrup, chief scientist for Polar Bears International and a co-author of the study. The models, he explained, may assume a better-than-reality body condition of the bears at the start of fasting periods. And the team used a cautious baseline estimate for how much energy a bear uses to maintain its body condition. “The impacts we project are likely to occur more rapidly than the paper suggests.”

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. Previous research has shown that even if we reduce greenhouse gas emissions tomorrow, it will still take another 25 to 30 years for sea ice extent to stabilise because of all the carbon dioxide already in the atmosphere. It’s important that the public understand the urgency of the issue, Amstrup said.

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