Polar bears suffer injuries due to Arctic sea ice changes

Researchers at the University of Washington have found cuts, hair loss, ice accumulation and skin ulcers in adult bears, mainly on the paws but also on other parts of the body.

The study, published 22 October in the journal Ecology, is the first time scientists have documented the phenomenon. They studied two populations of polar bears between 2012 and 2022 and noticed that many individuals developed these injuries. Two bears had ice blocks up to 30 centimetres in diameter on their paws, causing deep, bleeding wounds and making it difficult to walk.

The study's lead author, Christine Laidre, notes that climate change is leading to more frequent freeze-thaw cycles. This contributes to wet snow that sticks to the bears' paws and freezes to form ice. The bumps on the pads of the paws that help bears stay on slippery surfaces can contribute to snow sticking and freezing.

Scientists suggest three possible reasons for the increased accumulation of ice on polar bears' paws:

1. Increased instances of rain on snow: this creates wet, slushy snow that sticks to the paws and then freezes.

2. More frequent thaws: these cause surface snow to melt, which then freezes into a hard crust. Heavy bears fall through this crust, cutting their paws on its sharp edges.

3. Penetration of sea water into snow: thinning sea ice allows sea water to soak into the snow, creating moist conditions for ice to form on paws.

While this phenomenon clearly affects individual bears, researchers are still cautious about assessing its impact on the population as a whole.

We can reduce greenhouse gas emissions and try to limit global warming," Lydre said when asked about how to help polar bears.

Changes in sea ice structure are creating new challenges for polar bears to move around. The surface of Arctic sea ice is transforming, which can have a negative impact on these animals and their ability to adapt to a rapidly changing environment.