Melting the polar bears away?

This polar bear is photographed in Wager Bay in Canada. (Photo: Ansgar Walk)
The number of polar bears is likely to decrease by more than 30 percent in the coming decades, according to a new study by the International Union for Conservation of Nature (IUCN).

The number of polar bears is likely to decrease by more than 30 percent in the coming decades, according to a new study by the International Union for Conservation of Nature (IUCN).

The IUCN Polar Bear Specialist Group estimates the current global polar bear population at approximately 20.000-25.000 animals and confirms their status as "vulnerable" in last week‘s update of the Red List of Threatened Species.

Starving polar bears

The IUCN study determined climate change as the single most important threat to the long-term survival of the species. The retreat and the melting of the Arctic sea ice, on which the bears depend to access their prey, means that the polar bears will go for longer periods without food. Warmer temperatures in the Arctic will also affect seals and other prey species by reducing their habitat and making them more vulnerable to diseases.

This, in turn, will likely lead to starvation of the bears and decrease their reproductive success. Other major threats to polar bears are pollution, resource exploration and changes in their habitat.

In the past weeks, a photograph of an emaciated polar bear, taken in July from a cruise ship near Svalbard, went viral in social media. The skinny look of the apparently starving icon of the Arctic shocked the cruise passengers as well as observers worldwide and sparked a debate on the consequences of climate change.

Polar bear pictures taken by Paul Nicklen, a National Geographic fellow and renowned photographer of Arctic wildlife, also circulated on the Internet. Last year, he came across two dead bears in Svalbard: “These bears were so skinny, they appeared to have died of starvation, as in the absence of sea ice, they were not able to hunt seals.“ Still exceptionally rare a few years ago, sights of starving polar bears are now becoming more and more common.

Polar bears spend more time on land

Another study by researchers of the U.S. Geological Survey, the U.S. Fish and Wildlife Services and Brigham Young University was published last week in PLOS One. The study came to similar conclusions concerning the consequences of retreating sea ice for polar bears. The scientists surveyed the Chukchi Sea polar bear subpopulation and found that the bears spent more time on land in the summers. Apart from a decrease in the bears‘ access to food, which is probably offset by an abundance of food in the productive Chukchi Sea region, more time on land also means that human encounters become more likely.

Polar Bear Circumpolar Action Plan

To counter the decrease in polar bear population numbers, Canada, Greenland, Norway, Russia and the United States signed a 10-year agreement in September to proactively protect the bears and secure their long-term survival in the wild. Threats taken into account include melting sea ice, marine traffic, oil and gas exploration, as well as human-bear interactions. The new plan builds on the five nations‘ 1973 Agreement on the Conservation of Polar Bears. Margaret Williams, managing director of the WWF‘s U.S. Arctic programs, applauded the renewed commitment: “Today‘s multinational plan goes well beyond just protecting polar bears - by addressing larger threats facing the Arctic, it will have long-term benefits for the entire region.“

Stranded walrus looking for sea ice

The retreating sea ice in the Chukchi Sea also negatively affected other animal species and led to massive walrus haul outs in the last few years. Usually resting on ice floes, 35,000 walrus found it necessary to crowd ashore in Point Lay, Alaska, in 2014. On land, the animals are further away from their food sources. Moreover, large gatherings of walrus bear the risk of stampedes, in which smaller members of the herd might be crushed and killed.

In contrast to previous projections, recent studies demonstrate that the loss of Arctic sea ice has been faster than predicted. This year, the U.S. National Snow and Ice Data Center measured the fourth lowest minimum Arctic sea ice extent on record. The lowest Arctic sea ice extent since satellite measurements began in 1978 was recorded in 2012.

To be discussed at the United Nations Climate Change Conference

The latest studies demonstrating the impacts of Arctic sea ice loss on polar bears and other species are also highly relevant for the Paris Climate Change Conference, which is scheduled to start on November 30. Talking about the effects of climate change on ecosystems and biodiversity, IUCN Director General Inger Andersen said: "Governments meeting at the climate summit in Paris later this month will need to go all out to strike a deal strong enough to confront this unprecedented challenge.“