Loss of seasonal sea ice and the resulting increase in open water has led to an increase in shipping activities within the Arctic, and is expected to increase even more, given projections of ice-free summers in the Arctic by 2020-50. Potential effects of shipping on polar bears include disturbance, increased fragmentation of sea ice habitat (from icebreakers), pollution, and the introduction of waste/marine litter, as well as an increase in human-bear encounters and corresponding risk of defense kills.
Source: Circumpolar Action Plan