Polar bears numbers could plummet with climate change, according to a new study that showed females are giving birth to fewer cubs due to the loss of sea ice.

Polar bears give birth to fewer cubs if sea ice melts early, according to a new study. Photo: Steven J Kazlowski / SOLENT

Researchers at the University of Alberta looked at how melting sea ice in the 1990s effected the breeding success of polar bears.

During the spring and summer months the females are hunting seals on the ice to build up energy for the autumn and winter when they will hibernate for up to eight months and give birth.

The study found the early melting of the ice made it more difficult for the bears to hunt seals successfully and build up energy.

Therefore there is less chance of a successful pregnancy.

In the early 1990s 28 per cent of energy-deprived pregnant polar bears in the Hudson Bay region failed to have even a single cub.

Using mathematical calculations, the researchers estimated how melting sea ice could effect polar bear numbers in future.

The study, published in Nature Communications, found that If the ice breaks up two months earlier than in the 1990s, 55 to a full 100 per cent of all pregnant female polar bears will not have a cub.

If spring break up in Hudson Bay comes one month earlier than in the 1990s, 40 to 73 per cent of pregnant female polar bears will not reproduce.

The latest figures show that Arctic sea ice was at its lowest ever level this January since records began in 1979.

The polar-bear population of western Hudson Bay is currently estimated to be around 900 which is down from 1,200 bears in the past decade.

The number of polar bears across the Arctic is estimated to be between 20,000 and 25,000.

The study concluded that if sea ice continues to melt it could have a catastrophic effect on polar bears in the Hudson Bay area and across the Arctic.

(photo added by Axis of Logic)

Source: The Telegraph