One of the areas where warming is most noticeable is our polar regions. In the last 30 years the size of the polar ice cap has shrunk more than 20%. Average temperatures in the Arctic are rising twice as fast as other temperatures around the world. The largest single sheet of ice, the Ward Hunt Ice Shelf, started cracking in 2000 and split in half a mere two years later. It is now rupturing into pieces. As the Arctic ice thins, cracks and melts, it leads to even higher temperatures since, without the protective, cooling layer of ice, the Earth absorbs more light and energy from the sun.
Humans are not the only ones affected. Wildlife is already showing signs of stress and decline. The World Wildlife Fund warns that if solutions aren't found to stop the disappearance of pack ice, Polar bears will become extinct by the end of the century. Polar bears rely on pack ice to hunt their prey—seals and walruses. Adult bears need about 5lbs of seal fat per day, so, without the ice, bears are unable to build up the fat stores needed to survive in their harsh habitat. The WWF has a valuable Fact and Fallacies paper on the plight of the Polar Bear.
If you're looking for other facts about Polar Bears and want to share them with children, try this Polar Bear Zoobook. The Jungle Store has similar books on other animal species as well.