Melting ice sheets pose starvation risk for polar bears
Climate change-induced ice melts in the Arctic are posing a significant threat to polar bears, leading to starvation among some populations, reports BBC citing a study conducted recently.
Traditionally, polar bears rely on hunting ringed seals on Arctic sea ice for sustenance.
However, with the diminishing ice due to global warming, many bears are spending more time on land, where they struggle to find adequate food.
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Subsisting on bird eggs, berries, and grass, these bears rapidly lose weight, heightening the risk of mortality.
While the plight of polar bears has long symbolised the impact of climate change in the Arctic, the situation is multifaceted.
Although the population declined until the 1980s, primarily due to overhunting, legal protections have since led to a resurgence in numbers. Yet, rising global temperatures now present the most significant threat to their survival, as the frozen seas are crucial for their hunting activities.
A study conducted in Western Manitoba, tracking 20 polar bears over three summer seasons, revealed the challenges they face as ice disappears.
To understand how the animals survive, researchers collected blood samples, weighed the bears, and outfitted the bears with GPS-equipped video camera collars, enabling them to monitor the bears' movements and behaviors.
Despite adopting various survival strategies, including foraging for vegetation and berries or swimming in search of food, the bears experienced significant weight loss, with an average of one kilogram lost per day.
Reportedly, 19 of the 20 bears in the study lost body mass, by up to 11% in some cases.
Lead author of the study, Dr Anthony Pagano, said regardless of which strategy they were trying to use, there was no real benefit to either approach as far as being able to prolong the period that they could survive on land.
Two of the three bears that took to the water found carcasses of dead animals but spent only a short time eating, as they were too tired from their exertions.
"One sub-adult female found a dead beluga whale, she took a couple of bites from it, but she mostly used it as a buoy to rest on. It really suggests to us that these bears can't eat and swim at the same time," Dr Pagano told BBC News.
A notable discovery from the study was that one bear increased its weight by 32kg. The researchers speculate that this bear, which had predominantly focused on resting and conserving energy, was fortunate to come across an animal carcass.
While the research sheds light on the immediate challenges faced by polar bears, experts suggest that the impacts of climate change will vary by location.
While some regions may remain suitable for polar bears in the coming decades, others, like the study area in Western Manitoba, may face increasingly difficult conditions if sea ice continues to diminish as predicted.
"It is likely polar bears will disappear from areas where sea ice will be lost in future, but difficult to say just when and where," Jon Aars from the Norwegian Polar Institute who was not involved in the study told BBC.
"Some areas will have good conditions for bears also many decades from now. The area of this study is one where conditions may be very difficult for bears within a short time, if sea ice continues to disappear as predicted," he added.
