Andy Rouse / Polar bear (Ursus maritimus) standing on pack ice at the water's edge, Svalbard, Norway. June.

Steven Kazlowski / Polar bear (Ursus maritimus) mother with two juveniles walking along ice edge during autumn freeze up, Beaufort Sea, off Arctic coast, Alaska

Frederique Olivier / Emperor penguin (Aptenodytes forsteri) tobogganing on an iceberg at sunset and diving from the edge, seen from a moving boat, Antarctica.

Frederique Olivier / Group of Adelie penguins (Pygoscelis adeliae) diving from the edge of the sea ice, Antarctica.

Ingo Arndt / Coastal edge of Perito Moreno glacier, Patagonia, Argentina 2002

Jussi Murtosaari / European Dipper (Cinclus cinclus) on ice next to stream, winter, Finland. February.

Matthias Breiter / Polar Bear (Ursus maritimus) male at edge of sea ice, Churchill, Manitoba, Canada

Ross Hoddinott / Ice on black volcanic sand beach with waves, Jokulsarlon, Southeast Iceland, February.

Frederique Olivier / Adelie penguins (Pygoscelis adeliae) in front of French Icebreaker L'Astrolabe, on edge of the fast ice off Dumont D'Urville station, Antarctica. December 2014.

Steven Kazlowski / Polar bear (Ursus maritimus) sow with two juveniles walk along the ice edge during autumn freeze up, Beaufort Sea, off Arctic coast, Alaska

Frederique Olivier / Adelie penguins (Pygoscelis adeliae) travelling to the ice edge to feed, Antarctica.

Frederique Olivier / Adelie penguins (Pygoscelis adeliae) preening at edge of ice, Antarctica.