How is earth's changing climate influencing the lives of polar bears?
The largest threat to polar bears is currently climate change. Polar bears rely on ice for many things such as hunting, storing energy for the summer and autumn (when food is scarce), for raising their young, for creating dens, for finding their food, for camouflage, and the list goes on because the Arctic is their habitat, the only place where they can carry out their life activities. With temperatures rising, sea ice is now melting in early spring and forming in late fall. Not only is the bear's habitat shrinking, but their food is migrating away from them too. Seals, their natural prey, are unable to handle water temperatures that get too warm, so they either die or migrate elsewhere. Seals are the bear's main source of food. Since polar bears aren't getting as much food anymore, their health is declining which is leading to lower reproduction rates, especially because pregnant females need extra seal blubber in order to reproduce. At least half of the polar bear cubs born today either die from lack of food or lack of fat on their nursing mothers. Scientists have found that for every week earlier the ice breaks up in Hudson Bay, bears come ashore roughly 10 kg (22 lbs) lighter and in poorer condition. With lower reproduction rates increasing, the polar bear could eventually go extinct.