Polar bears just might outlive us all

On January 24, 2004, in the frigid moonscape of an Arctic winter, wildlife biologist Steven Amstrup rode in a helicopter flying low over the ice. Using an infrared heat detector, he hoped to find polar bears in their dens. When the gun recorded a hit, Amstrup circled around for a closer look. What confronted him was something he had never seen in 34 years of research.