What does global warming have to do with the decline in the polar bear population?

Polar bears are dying as Arctic ice melts. See more pictures of arctic animals.
Rory Gordon / Michael Ramage/Gallo Images/Getty Images

The largest carn­ivores on land are getting squashed like tiny bugs. Measuring up to 10 feet tall ­(3 meters) and weighing in at up to 1,700 pounds (771 kilograms) polar bears are formidable creatures. But the massive animals are struggling with a global predator -- climate change -- and they're losing.

Scientists have been talking about melting polar ice caps and rising sea levels for decades. Now, it's not just talk. The average temperature in the Canadian Arctic has risen 7 degrees Farenheit (4 degrees Celsius) in the last 50 years [source: Daily Mail]. Temperatures in the Arctic Circle are increasing at twice the rate of the rest of the world's climate [source: Yahoo News]. The Arctic ice is melting, and the seas are becoming more treacherous. This is bad news for polar bears.­

The polar bear habitat is about as frigid as it gets, and the animals are ideally suited to survive in the tough environment. They have several inches of both fur and blubber to insulate them from temperatures that drop to -49 Fahrenheit (-45 Celsius) in the dead of the Arctic winter. They've evolved to thrive under these conditions.

But what happens to a species when its ideal habitat starts to disappear? As we'll find out in the next section, it's not pretty at all.