evidence: Polar Bears and Arctic Sea Ice Polar bears roam across the circumpolar Arctic, where they rely on sea ice to reach their seal prey. But not all sea ice is equal. Learn about the four sea ice ecoregions, how the quality of sea ice differs across the polar bear’s range, and how we can help ensure the bears’ future by addressing climate change. [...] The number of polar bears worldwide is not increasing. Some populations are recovering after their numbers were vastly reduced by uncontrolled hunting in the 1960s, but that potential for growth is running head first into declining carrying capacity in some regions due to loss of sea ice habitat.