The world's southernmost polar bears could disappear within years due to warming temperatures, a bad omen for the rest of their brethren, researchers warn in a new report. Polar bears have long found a home on Canada's Hudson Bay, the largest northern inland sea, whose shallow waters freeze over in winter. They navigate sea ice in search of seals before moving to land, where food sources can't sustain them, in summer, per Smithsonian. But with warming temperatures, sea ice is forming later in the fall and disappearing earlier in spring, shortening the period that bears can build up the fat needed to survive. According to researchers, the death knell could come if temperatures climb as little as 1.6 degrees Celsius above preindustrial levels, a point we may have already reached.
The southern population of Hudson Bay polar bears will starve if global temperatures rise between 1.6 to 2.1 degrees Celsius above preindustrial levels, while the western population will vanish if temperatures rise between 2.2 and 2.6 degrees Celsius, according to the study published Thursday in Communications Earth & Environment. Researchers used the latest climate models to predict when a lack of strong sea ice would force polar bears to remain on land to the point of starvation, per CBC News. This is predicted as soon as the 2030s for the southern population and by the 2060s for the western population. Interestingly, researchers assumed sea ice would need to be roughly 4 inches thick to support a large male polar bear, though some experts believe this to be a severe underestimate.
Without sea ice to support them, polar bears will lose access to their main food source and starve, researchers say. "I think we need to start telling people, sadly, the harsh realities of what's to come if we don't do anything," lead study author Julienne Stroeve, a polar climate scientist at the University of Manitoba, tells the CBC, noting we're on track for 2.7 degrees of warming by 2100. "It's going to transform the entire Arctic region beyond contemporary recognition." While other polar bear populations might be able to relocate to areas with longer-lasting ice, Hudson Bay polar bears don't have anywhere else to go, "in part because the way that the sea ice drifts with the winds," Stroeve adds. And in the lead-up to localized extinction, the bears are likely to visit nearby communities "looking for something to eat," a local tells the CBC. (More polar bears stories.)
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