An international team of scientists has issued a stark warning about the future of polar bears in Canada’s Hudson Bay, predicting local extinction by mid-century if global warming continues unchecked beyond the targets set by the Paris climate accords. According to their findings, published recently, the rising temperatures are rapidly diminishing the sea ice essential for the bears’ survival.

Climate change has significantly altered the Arctic landscape, leading to longer periods where the sea ice is too thin for polar bears to hunt their primary prey, seals. This forces the bears to spend extended durations on land, without access to their main food source, which is crucial for their survival and reproductive success.

Using advanced models to project future scenarios, researchers focused on how escalating global temperatures would impact ice thickness in Hudson Bay—a critical habitat for polar bears. Their simulations indicate that if temperatures rise by 2 degrees Celsius above pre-industrial levels, the ice-free season in Hudson Bay would become too prolonged for many polar bears to endure.

The study’s lead scientist emphasized that bear populations in the southern region of Hudson Bay, where winter ice is slower to return, would face the most immediate threat. These bears, she warned, are unlikely to survive in their current habitat beyond the middle of this century if warming trends persist.

Furthermore, the collapse of polar bear populations in other parts of Hudson Bay would swiftly follow suit, with habitat conditions becoming increasingly unsuitable for hunting and breeding as temperatures continue to rise beyond 2 degrees Celsius.

Under the 2015 Paris agreement, nations pledged to limit global temperature increases to well below 2 degrees Celsius, with an aspirational goal of capping warming at 1.5 degrees Celsius to mitigate the severe impacts of climate change. However, current trends indicate that global temperatures have already surpassed the 1.2 degrees Celsius mark compared to pre-industrial levels, and projections suggest a trajectory towards nearly 3 degrees Celsius of warming by the end of this century, as reported by the United Nations.

The rapid warming of the Arctic has led to longer periods without sea ice during summer months, compelling polar bears to remain on land for extended periods. During these ice-free periods, polar bears can lose significant body weight, up to two kilograms per day, due to the lack of access to their prey.

Human-induced climate change has notably extended the ice-free season in Hudson Bay by approximately one month over the past decade alone, according to the study published in Communications Earth and Environment. If global temperatures rise by 2 degrees Celsius, the southern part of Hudson Bay could experience ice-free conditions for more than 180 days—a critical threshold beyond which polar bears may struggle to survive, the scientists cautioned.

Researchers expressed concerns that polar bear breeding and population numbers are already being severely impacted by the prolonged ice-free periods in Hudson Bay, suggesting that local extinction may be inevitable if current environmental trends continue unabated. The ecosystem changes happening at such a rapid pace may outstrip the ability of polar bears and their prey to adapt, leading to dire consequences for these iconic Arctic animals.

Efforts by polar bears in Hudson Bay to adapt to longer periods on land by seeking alternative food sources have proven inadequate in providing the necessary calories compared to their traditional marine diets. This adaptation challenge underscores the severe impact of climate change on the delicate balance of Arctic ecosystems and the species reliant upon them.

The scientists highlighted that the past twelve months have been recorded as the hottest in history, marked by unprecedented highs in both land and ocean temperatures. They noted with concern that southern parts of Hudson Bay are already experiencing ice-free conditions, a phenomenon typically not observed until early July in previous years.

The findings from Hudson Bay serve as a dire warning for the fate of polar bears across the broader Arctic region. As the southernmost population of polar bears, those in Hudson Bay have long been regarded as an indicator of the challenges facing their counterparts further north. The potential local extinction of polar bears in Hudson Bay serves as a wake-up call, signaling the possible future for polar bear populations elsewhere in the Arctic if urgent global action to curb greenhouse gas emissions is not taken.