Danny Green / Polar Bear (Ursus maritimus) on sea ice. Svalbard, Norway, July.

Pete Oxford / Pack ice off Saunders Island, South Sandwich Island, Falklands 1998

Doug Allan / Sunset on frozen pack ice, Canadian Arctic

David Noton / Pack ice in Alexandra fjord, Ellesmere Island, Canadian Arctic

Doug Allan / Aerial view of sea ice breaking up in late spring, Lancaster Sound, Canadian Arctic

Ben Osborne / Crested auklet flock fly over packice {Aethia cristatella} Talan Is, Okhutsk Sea, E Russia

Ben Osborne / Crested auklet flock fly over packice {Aethia cristatella} Talan Is Okhutsk Sea E Russia