Polar bears fight for survival as sea ice melts - video

As winter approaches, polar bears in sub-arctic Canada begin to migrate off the tundra and head out onto the ice for the winter, where they can hunt for seals. However, climate change is delaying freeze-up, keeping the bears out on the tundra for longer - away from their main food source. US environment correspondent Suzanne Goldenberg talks to polar scientists ahead of a live Q&A from Churchill, Manitoba Continue reading...