Most likely it will die unless it receives care quick after. A polar bear's natural habitat is to be in cold weather, and their bodies are adapted to the snow. Humans find deserts unbearably hot after a couple of minutes, but we don't have long, thick coats of fur on us. Unless a polar bear is in an oasis in a desert during winter, it'll probably die right away of heat. On top of that, a polar bear eats like twenty times what we do. If heat wouldn't kill it, starvation would. I hope that never happens :(
