Polar bears are endangered. One of the greatest threats facing this animal is global warming, resulting in melting sea ice, which is an important component of the polar bear's habitat. According to pictures taken by satellites since 1979, the sea ice as of 2014 is lower than it has ever been in that 35-year period.
Sea ice is important for the polar bears' survival because they need it as a platform to hunt seals. Seals cut breathing holes in the ice. Polar bears find these breathing holes and wait for a seal to come up to breathe before pouncing. Polar bears also stalk and kill seals sunning on top of the ice.
Polar bears can only hunt as long as the sea ice is present. With global warming, the sea ice is disappearing sooner and not reforming until later in the season, leaving polar bears without enough hunting time. Polar bears must swim to the ice to hunt. With disappearing sea ice, this results in longer swims and less productive hunting, causing many bears and cubs die.
The polar bears are fasting for longer periods of time during the summer months. As a result, they have fewer young, and the young that they do have often have a higher mortality rate.