The Intergovernmental Panel on Climate Change and the Arctic Climate Impact Assessment have both predicted that the Arctic is extremely vulnerable to projected climate change. The most pronounced changes to the Arctic are likely to include increased temperatures and changes in precipitation patterns: both which will affect sea ice patterns and ultimately, polar bears. Polar bears will likely be shifted pole-ward if the sea ice retreats. As a matter of fact, according to new scenarios presented by the Nansen Environmental and Remote Sensing Centre, the polar ice cap will disappear almost entirely during summer in the next 100 years.
Because polar bears feed almost exclusively on ice-associated seals, changes in the sea ice that affect access to prey will have a negative effect on the bears. In particular, if more snow falls, polar bears are less successful at breaking into the birth lairs of ringed seals. If too little snow falls, ringed seal pups are born on the sea ice without a lair and this makes them very vulnerable to predation by polar bears and arctic fox. With less food, polar bears will fail to reproduce more often and give birth to smaller young that have higher mortality rates.