Researchers studying polar bear populations in the high Arctic have found evidence of ice buildup and related injuries affecting the feet of adult bears due to changing sea ice conditions in a warming Arctic. These injuries, including lacerations, hair loss, and skin ulcerations, are primarily affecting the feet of polar bears, making it difficult for them to walk. The study, published in Ecology, is the first to document these types of injuries in polar bears.
The shift from a climate that used to remain well below freezing to one with more freeze-thaw cycles has led to an increase in ice buildup on polar bears’ paws. More frequent freeze-thaw cycles with wet snow are causing ice to accumulate on the bears’ feet, resulting in painful injuries. Researchers studied two polar bear populations living above 70 degrees north latitude between 2012 and 2022 and observed a high prevalence of icing-related injuries in both populations.
In the Kane Basin population between Canada and Greenland, 31 out of 61 polar bears showed evidence of icing-related injuries, while in East Greenland, 15 out of 124 polar bears exhibited similar injuries. Two bears in East Greenland in 2022 had massive ice balls up to 1 foot in diameter stuck to their feet, causing severe pain and difficulty walking. These injuries were not observed in previous studies of these populations, suggesting this is a recent phenomenon.
The authors hypothesize that climate warming is causing three possible reasons for increasing ice buildup on polar bears’ paws. More rain-on-snow events, warm spells causing surface snow to melt and refreeze into hard crusts, and seawater seeping up into snow due to thinning sea ice near glaciers are all contributing factors to the ice accumulation on polar bears’ feet. These changing climate conditions are creating challenging surface conditions for polar bears to travel on, affecting their overall health.
While the bears are clearly being affected by the ice buildup, researchers are cautious about drawing broader conclusions about the health of the populations. It is unclear how these injuries may impact polar bear populations at a broader level. The researchers emphasize the importance of reducing greenhouse gas emissions to limit climate warming and protect polar bears from further ice-related injuries.
Overall, the study highlights the unexpected responses of polar bears to climate change, such as increased ice buildup on their paws. By understanding these impacts and taking action to mitigate climate change, we can help protect polar bears and other Arctic wildlife from the negative effects of a warming Arctic. The field observations of polar bears were funded by several governments, and researchers continue to monitor the health of these populations to better understand the long-term implications of changing sea ice conditions.