One of the environmental claims about the alleged Anthropogenic Global Warming of planet Earth which won Al Gore a (Wholly unjustified) Nobel prize was about Polar Bears being stranded on a rapidly diminishing Arctic ice pack. To be specific, his whole argument was centered around one photograph. One photograph, that's all. He completely ignored the recent increase in the Polar Bear population in Northeastern Canada. Not to mention the fact that the population elsewhere is stable, rather than the catastrophic decrease in the numbers of Ursus Maritimus that some parties allude to. As an 'endangered' species, they tend to fall into a 'vulnerable' endangered category, rather than the 'critical' end of the scale that some might want you to believe. Extinction is a long way off.
Polar Bears, are what are called apex predators (Top of the food chain) that can survive sub zero temperatures and swim up to 100 miles. They may be white and furry, but they sure as hell ain't cute. An old family friend of ours who worked on the first radar surveys in the Arctic was once stranded on the ice and has told me how terrifying these critters are close up. They are one of the few creatures on this Earth that will actively stalk humans. To them, we're an easy kill, a Seal that has learned to walk upright and which can't run fast enough. They even resort to cannibalism when food is really short. Strangely enough they can also successfully interbreed with other species of Bear like the Kodiak Grizzly.
During the current arctic climate conditions, some of the Polar Bears aren't doing so well, some are doing fine. Some of this, like the concentration of pollutants in their blubber, is human linked because they will eat anything (There is even a well documented account of one having a chew at USS Connecticut's rudder which it may have thought was a dead whale). In Churchill Manitoba, some of the local Bears had been found to eat garbage and even dumped car batteries at the local tip. Notwithstanding, the dump was shifted to a location outside of their range.
Despite four highly publicised and quoted 'drownings' in 2005 Polar Bears as a whole seem to have adapted well during the temporary warm period we're coming to the end of, building dens on land as opposed to the ice. Ironically as the Arctic gets colder, and the ice thickens they may even become even more endangered because they will have to cover more pack ice to find food.
My own anecdotal evidence about the state of the Arctic sea ice is this; last year I flew Air Canada over the Arctic at the height of summer (July). From the air I saw 'leads' between the ice pack and land which is normal at that time of year, also huge tracts of barren Nunavut where the ice had melted. Even then there were lakes clogged with ice floes. From my thankfully warm and comfy window seat I also saw near unending sheets of sea ice.
Couldn't see any bears from that height of course, but according to the experts, they are down there, and many of them are doing very nicely thank you.