Global warming: Polar bears could go extinct as early as the 2030s

The future of polar bears in Hudson Bay, Canada, looks bleak: a new study warns that the bears could disappear regionally as early as the 2030s if global warming continues to rise and crosses critical thresholds.

Researchers from several North American and international institutions warn that a global temperature increase beyond two degrees Celsius could have catastrophic impacts on polar bears in southern and western Hudson Bay. Published in the journal Communications Earth & Environment, the report analyzes different warming scenarios and their effects on sea ice, seals, and polar bears.

Ice-free days in Hudson Bay are increasing

Hudson Bay, a marginal sea of the Arctic Ocean that is seasonally covered by ice, is home to large populations of polar bears (Ursus maritimus). Each year in July, the retreating sea ice forces the bears to come ashore, where they rely on fat reserves during the ice-free months until they can return to the ice in winter and resume hunting seals.

Research based on climate models, satellite data, and simulations shows that a warming climate significantly reduces the number of days Hudson Bay is covered by sea ice. This would have dramatic consequences not only for polar bears, but also for ringed seals (Pusa hispida), one of their primary food sources. The shrinking sea-ice cover undermines the seals’ livelihood, as they build their dens in deep snow on the ice.

Warming driven by climate change has already lengthened the ice-free season in Hudson Bay, leading to declines in polar bear populations—especially in western Hudson Bay. This decline, observed as early as the 1990s, is primarily due to earlier sea-ice breakup.

Even with a moderate warming of 1.6 degrees Celsius—a threshold the world has almost reached—polar bears in southern Hudson Bay may not survive. At two degrees of warming, ice-free periods in this region are expected to last between 174 and 182 days. Most ecologists believe polar bears would not withstand a fasting period of more than 180 to 200 days.

Urgent global action needed

The future of polar bears and ringed seals in Hudson Bay faces severe challenges. To combat the impacts of climate change and improve these species’ chances of survival, global efforts are required. Everyone can contribute by reducing emissions and minimizing their own CO2 footprint. However, decisive measures at national and international levels are also necessary—putting sustainability ahead of profit.

Although the current report focuses primarily on the impacts of climate change on polar bears and Hudson Bay, its findings can also be applied to other parts of the world that depend on specific ecosystems. Climate change is also threatening coral reefs in Florida and Australia. A sad example of its effects is the extinction of the Bramble Cay mosaic-tailed rat, whose habitat—the island of Bramble Cay—was swallowed by rising sea levels between 2009 and 2011.