Polar bears depend on sea ice as a platform from which to hunt seals, rest and breed. For more than 20 years the summer sea ice has been decreasing in size and melting for longer periods of time. Bears must move longer distances to stay with the rapidly receding ice.
In most areas, they come ashore when ice melts and rely on fat stores until the ice refreezes so they can go back out to hunt. Some polar bears, especially in the south of their range where sea ice is gone longest, now suffer from malnutrition. In extreme cases—especially females with cubs— they may face starvation.
Traditional prey species may be less accessible in a new sea ice environment, and seals that use the ice are predicted to fare poorly in the warming Arctic region.
Climate change is also resulting in more habitat fragmentation. As Arctic ice melts, polar bears are affected by increased shipping activities and a rise in opportunities for oil and gas development.