Researchers have discovered a new type of injury in polar bears linked to climate change.

Environmentalists have long warned that global warming, which is altering the lifestyle of polar bears, jeopardizes their existence. Although some populations have learned to survive with limited access to sea ice, this option is unlikely to save the species as a whole.

As part of programs aimed at studying and preserving polar bears, scientists from various countries are monitoring them in the wild. In one such project, researchers from Canada and the USA tracked the health of two polar bear populations living in the regions of Cain Basin and East Greenland from 2012 to 2022.

Experts found that adult bears began to suffer from ice growths that damaged their limbs. Ice chunks stuck to their paws severely hindered their ability to walk, leading to deep cuts, ulcers, and lacerations. The researchers discussed these findings in a recently published article in the journal Ecology.

The researchers noted that while observations of polar bears in these areas have been ongoing since the 1990s, such injuries had never been documented before. In one population, signs of ice-related injuries were recorded in 31 out of 61 bears, while in the other, 15 out of 124 bears showed similar signs. A review of scientific literature and surveys of local hunters confirmed that this is a recent phenomenon.

According to the authors of the article, the ice growths on the paws of the two most affected individuals were so large that the bears could not run and struggled to walk. Temporarily immobilizing the animals, the scientists removed the ice chunks covered in snow that had adhered not only to the fur but also to the skin.

The researchers believe that the issue is related to the structure of polar bear paws. Their pads are covered with bumps that enhance grip on surfaces and help reduce slipping. This feature can lead to more snow sticking to their paws and compacting into ice lumps. A similar situation is observed in sled dogs.

When discussing potential factors contributing to the bears' injuries due to icing, the scientists noted that with climate warming in the Arctic, cycles of melting and freezing have become more frequent, along with precipitation in the form of rain mixed with snow. Wetter snow forms lumps more quickly and sticks more to the paws, which can then easily turn into ice with subsequent cold spells.

Additionally, due to repeated thawing and freezing, the snow cover often hardens into a solid crust with sharp edges at breaks. Stepping on such surfaces can also injure the pads of the bears' paws.

Finally, with warming, sea ice along the coastline has thinned and allows more water to pass through, which also increases the humidity of the snow and makes it stickier.

While the scientists have described the problem, they refrained from drawing conclusions about its consequences.

“We have seen individual polar bears with injuries related to icing, but I would not rush to conclusions about how this might affect the population. We really do not know,” concluded one of the researchers.