Arctic changes drive polar bear decline

Higher temperatures are having dramatic effects on the Arctic ice, forcing polar bears to move greater distances and making it harder for them to catch prey, a new has study found.

This has resulted in a growing number of bears unable to find enough food to meet their energy needs, which are more than 50% higher than previously thought.

Published in the journal Science, the study estimates a 40% decline in the polar bear population amid thinning Arctic sea ice in the Beaufort Sea area over the last ten years.

"We've been documenting declines in polar bear survival rates, body condition, and population numbers over the past decade," study author and Ph.D candidate at the University of Santa Cruz, Anthony Pagano, said.

"This study identifies the mechanisms that are driving those declines by looking at the actual energy needs of polar bears and how often they're able to catch seals.”

The research involved attaching high-tech collars to nine adult female polar bears, which recorded video, locations and energy levels over a period of eight to 11 days.

This technology allowed the researchers to study the fundamental biology and behavior of the animals in a remote and harsh environment, observing their movement on ice and activity patterns.

It was found that, as the Arctic warms and sea ice melts, polar bears are having to move much greater distances than previously recorded in the 1980s, causing them to expend more energy.

Five of the nine bears studied lost body mass, despite it being at the start of the period that they catch most of their prey and put on the body fat needed to sustain them throughout the year.

The study comes after NASA-supported satellite imagery found that minimum Arctic sea ice has declined by an area around a quarter the size of Europe in the last 30 years.

“From space, the loss of Arctic sea ice is the clearest and most visible sign of climate change, and human beings are responsible for most of it,” says WWF head of polar programmes, Rod Downie.

“The Arctic is in a changed state, but by tackling climate change head on and reducing our carbon emissions, we can help to stabilise it for future generations.”

Image credit: iStock