For nearly 35 years George Divoky has been returning to Cooper Island, a small, low strip of desolate land close to Barrow, AK. Initially he went there simply to study Black Guillemots, but as - over the decades - he tracked the dates of their arrival and the new chicks hatching, he realized he was documenting how climate change was affecting both an organism and an ecosystem. As summer ice retreated, food for the chicks was harder and harder to find - and polar bears began to roam the beach.