Loss of Arctic sea ice owing to 'Climate Change' is the primary threat to polar bears throughout their range. This is leading to large declines in polar bear numbers.
Temperatures in the Arctic are rising at least twice as fast as the global average and sea ice cover is diminishing by nearly four per cent per decade.
The loss of sea ice affects polar bears’ ability to find food.
With the ice retreating earlier in spring and forming later in winter, the bears have less time to hunt prey and have to go without food for longer.

There are other impacts of climate change on polar bears, too. Warming has been linked to increases in contamination and exposure to diseases. Unusually warm weather in winter can cause dens to collapse, which females build to birth and protect their young.

"Without sea ice, there is no sea ice ecosystem and losing that ecosystem includes losing polar bears"