Polar bears are suffering horrific paw injuries, and it’s all due to climate change, a new study warns.
Scientists who studied Arctic mammals for 10 years found lacerations, skin ulcers and hair loss in more than 40 of the creatures.
Experts believe warmer temperatures are melting snow into sleet.
This sleet refreezes at sharp angles, causing lacerations in mammals that are accustomed to treading on relatively soft snow.
Polar bears already have to deal with longer Arctic summers and a general loss of sea ice, which is reducing access to their prey and leaving them stranded.
But these newly documented ice-related injuries, detailed in a study for the first time, could prove just as deadly.
Although experts were unable to “follow the fate of the individual bears,” the injuries could reduce their ability to travel and hunt, further harming the population.
Studying the health of two populations of polar bears, researchers found lacerations, hair loss, ice buildup, and skin ulcerations that primarily affected the adult bears’ paws, as well as other parts of the body.
Here, three adult polar bears travel across sea ice in eastern Greenland. Bears already have to deal with longer Arctic summers and a general loss of sea ice, which is reducing access to their prey and leaving them stranded.
The new study was led by Professor Kristin Laidre, a scientist at the Polar Science Center, Applied Physics Laboratory, University of Washington.
“In addition to the expected responses to climate change for polar bears, there will be other unexpected responses,” he said.
“Strange as it may seem, with climate warming there are more frequent freeze-thaw cycles and more wet snow, causing ice to build up on the paws of polar bears.”
Between 2012 and 2022, Professor Laidre and co-author Stephen Atkinson, a wildlife veterinarian, studied two populations of polar bears in eastern Greenland and the Kane Basin, located between Canada and Greenland.
In the Kane Basin population, 31 of 61 polar bears showed evidence of ice injuries, including bald spots, cuts and scars.
In the second population, in eastern Greenland, 15 of 124 polar bears suffered similar injuries.
What’s more, two Greenland bears had blocks and balls of ice up to 30cm in diameter stuck to the pads of their paws, causing deep, bleeding cuts and making it difficult for them to walk.
After sedating the creatures, the researchers carefully removed the ice balls.
Pictured, severe ice buildup on the hind pads of a sedated adult male polar bear in eastern Greenland in April 2022.
Between 2012 and 2022, Professor Laidre and her co-author studied two populations of polar bears in eastern Greenland and the Kane Basin (located between Canada and Greenland).
“The two most affected bears couldn’t run, they couldn’t even walk very easily,” Professor Laidre said.
“The ice chunks were not only trapped in the hair, but were sealed to the skin, and when the feet were palpated it was evident that the bears were in pain.”
More hot spells caused by global warming are thought to be causing surface snow to melt and then refreeze into a hard crust.
Heavy polar bears break through this ice crust and cut their paws with its sharp edges.
Additionally, researchers note that climate change has been linked to more precipitation, because warmer air can hold more water.
As a result, increased precipitation creates more wet, slushy snow that accumulates in the paws and then freezes to form a solid once temperatures drop.
Polar bears have tiny bumps on the pads of their paws that help provide traction on slippery surfaces.
However, these bumps and the substantial amount of hair that grows around the toes and bottom of the foot make it easier for wet snow to freeze on the paws and accumulate.
In the photo, an example of ulcerative lesions on the paw of a polar bear. Note the tiny bumps on the foot pads that help provide traction on slippery surfaces.
It is already known that the Arctic sea ice surface has less snow in late spring and summer, due to climate change.
The snow that does exist is melting earlier and episodically and it is raining more frequently, which unfortunately means that these injuries could continue and even increase.
The new study, published in the journal Ecologyoffers another reason why humanity needs to reduce greenhouse gas emissions and try to limit climate warming.
The team concludes: “As climate warming continues, there is potential for the conditions we describe (as well as other unforeseen phenomena resulting from an altered physical environment) to have individual and potentially population-level effects.
‘Climate change has broad ecological implications for wildlife, especially for species that depend on temperature-sensitive habitats.
“These lesions have not been observed during previous research in these areas nor have they been reported in the scientific literature.”