Polar bears are in danger of being wiped out unless urgent measures are taken to combat climate change and rapid warming in the Arctic, environmental group WWF warned Thursday."No sea ice equates no polar bears. It's really that simple," WWF polar bear expert Geoff York told reporters.York was speaking in Oslo days before representatives of the five countries bordering the Arctic were set to meet in the northern Norwegian town of Tromsoe on March 17 to discuss how to safeguard the bear.The WWF insisted the Arctic countries had a special obligation to spearhead efforts to reduce emissions of greenhouse gases."People have caused the problem, people have to fix it," said Rasmus Hansson, the head of WWF Norway, adding that several of the five Arctic nations "are also extremely important (to the development of) international climate change policies."The three-day Tromsoe meeting grouping Canada, Denmark (with Greenland), Norway, Russia and the United States will discuss how to address threats against the polar bear that have emerged since they first signed a conservation agreement in 1973.Back then, hunters were the only known threat against the white bear."Nobody thought about climate change at that time," said scientist Thor Larsen, who helped negotiate the 1973 accord.More than three decades after the signing of the agreement however, WWF says climate change is now "the predominant threat" facing the majestic Arctic animal."Speaking about polar bears without addressing climate change is like discussing cod without wanting to speak about the sea," Hansson said.As many as two thirds of the 20-25,000 polar bears that roam the Arctic could disappear within the next 50 years due to global warming, according to recent estimates from the US Geological Survey (USGS) and the International Union for Conservation of Nature.And climate change is not the only thing threatening the bears today.They are also increasingly exposed to toxic substances like PCB that flow into the region on the back of ocean and atmospheric currents, breaking down the mammals' immune systems and reproductive capabilities.This in turn further complicates their ability to adapt to the shifting climate.The Tromsoe meeting comes at "an extremely important moment," ahead of the talks on a new global pact on climate change in Copenhagen in December set to replace the Kyoto accord, Hansson said.In the United States, President Barack Obama "has sent completely different signals than the previous administration on climate issues," he added.According to some estimates, the Arctic sea ice that makes up the polar bear's hunting ground could completely disappear during the summer months by 2020.It is not too late to act, said York, who used to work for the USGS. He cautioned however that "oil, mining, shipping and military activities did not exist in previous times of warming," calling for all these activities to be reined in across the region. WWF also warns that the problems facing polar bears today serve as an indicator for how the ecosystem is being affected, something that will eventually have serious implications for humans. "If polar bears run into serious troubles, then we human beings are in for serious troubles too," Hansson said.