A new fossil find shows that Polar Bears have been around for well over 100,000 years, placing them in the Eemian Interglacial period (135 to 115k BP). During that time, temperatures were significantly warmer than at present (+5C). And clearly they survived those temperatures. It sounds as though forecasts of their imminent extinction may be a bit premature.
Quaternary geologist Professor Dr. Olafur Ingolfsson of the University of Iceland discovered the new fossil. He says “The polar bear is basically a brown bear that decided some time ago that it would be easier to feed on seals on the ice. So long as there are seals, there are going to be polar bears. I think the threat to the polar bears is much more to do with pollution, the build up of heavy metals in the Arctic”.

Indeed despite the alarmist claims, serious studies show that the polar bear is doing rather well, with populations increasing. For more on this, see:

http://news.bbc.co.uk/1/hi/sci/tech/7132220.stm