The changing climate and prolonged periods without Arctic Sea ice pose a severe threat to polar bears in Canada’s Hudson Bay, leading to potential starvation despite the bears’ adaptability in expanding their diets.
Typically relying on the ice-covered ocean surface to access their primary prey, fatty ringed and bearded seals, polar bears face challenges as human-induced climate change extends the ice-free periods in the Arctic, particularly in areas heating two to four times faster than the global average.
Research conducted on 20 polar bears in Hudson Bay, published in the journal Nature Communications, reveals that the bears, when without sea ice, actively search for alternative food sources instead of conserving energy during warmer months. Using video camera GPS collars over three years, the study found that, despite two bears entering a hibernation-like state, the remaining 18 bears remained active, exploring the landscape for sustenance.
These active bears exhibited diverse behaviors, such as consuming grasses, berries, a gull, a rodent, and a seal carcass. Some undertook lengthy swims, with one covering 175km, while others engaged in playful activities or gnawed on caribou antlers. However, the researchers noted that these efforts did not provide enough calories to match the bears’ usual marine mammal prey.
Nineteen out of the 20 polar bears studied lost weight during the extended ice-free period, indicating a heightened risk of starvation.
The findings underline the urgent need to address climate change and reduce greenhouse gas emissions to protect polar bear populations. The study supports existing research and emphasizes the dire consequences of prolonged ice loss.
With global temperatures continuing to rise, surpassing the Paris Agreement target of 1.5°C above pre-industrial levels, and diminishing sea ice, the future survival of polar bears hinges on decisive climate action.
Anthony Pagano, a research wildlife biologist with the US Geological Survey and lead author of the study, highlighted the creativity and adaptability of polar bears in seeking food resources when motivated. However, the study’s results paint a concerning picture, indicating that the bears’ efforts on land are insufficient to meet their caloric needs compared to their usual marine mammal prey.
The repercussions of prolonged ice loss extend beyond the individual bears studied. The entire population of polar bears, numbering around 25,000 remaining in the wild, faces an increased risk of endangerment due to the climate crisis. Limiting the rise in global temperatures, in line with the Paris Agreement target of 1.5°C above pre-industrial levels, is crucial to preserving polar bear populations, according to Pagano. However, the reality is that global temperatures have already reached 1.2°C, and urgent action is needed to curb further increases and mitigate the impacts of climate change.
John Whiteman, the chief research scientist at Polar Bears International, emphasized that stopping ice loss is the only solution to safeguarding polar bears. The study’s direct measurement of the bears’ energy expenditure during ice-free periods provides valuable insights into the challenges these iconic creatures face as their habitat continues to be threatened.
Melanie Lancaster, senior Arctic species specialist for the World Wildlife Fund, emphasized the study’s contribution to the existing body of research, sounding an alarm about the perilous situation of polar bears. As the world grapples with the consequences of climate change, the plight of polar bears serves as a poignant reminder of the urgent need for global collaboration to address environmental issues and protect endangered species from the devastating impacts of a changing climate.
