Melting ice to blame for polar bears getting thinner and having fewer cubs

Polar bears might be the biggest animals being affected by the impacts of climate change. 

A new study published in Ecological Applications, an ecological science journal, found that polar bears were becoming thinner and having fewer cubs.

Researchers have tied the bears' declining health to melting sea ice, according to a new CNN report.

Kristin Laidre, study author and professor of aquatic and fishery sciences at the University of Washington, said, "Climate-induced changes in the Arctic are clearly affecting polar bears," adding that the polar bears were an "icon of climate change" and "an early indicator of climate change because they are so dependent on sea ice."

The researchers of the study had tracked the movement of adult female polar bears off the west coast of Greenland over two phases: first in the 1990s, and then 2010s.

They found that the bears had spent on average 30 more days on land during 2009-2015 than they did during 1991-1997, due to sea ice melting at a faster rate than before.

Of the 352 bears analysed, less than 50 were now considered fat.

According to the researchers, the more time the polar bears spent on land, the more they were unable to hunt, and had to wait until there was "enough sea ice to hunt seals from," reported CNN.   

This was also tied with them having fewer cubs, as female polar bears have more cubs when sea ice is more widely available. 

The occurrence of "spring breakup," the time when ice melts and water becomes more available, occurring later in the season, has made it difficult for polar bears to maintain their two-cub litters, which have been seen as the norm among healthy adult females.