Climate change speeds up the polar bear treadmill

Sea ice in the Alaskan Arctic drifts from east to west, meaning polar bears have to walk eastward just to stay in the same place. However, sea ice has started moving faster in recent years, forcing bears to work harder. Learn about the causes and consequences in my podcast for Scientific American.

Polar bears spend most of their lives on drifting sea ice. (Credit: Alan Wilson via Wikimedia).