Colin Monteath / Heavy pack ice, Terre Adelie Land, east Antarctica

Jim Brandenburg / Polar Bear (Ursus maritimus) walking across ice floes, Ellesmere Island, Nunavut, Canada

Flip Nicklin / Polar Bear (Ursus maritimus) hauling out on ice floe, Wager Bay, Canada

Colin Monteath / Adelie Penguin (Pygoscelis adeliae) group on icefloe in Hope Bay, Antarctic Peninsula, Antarctica

Colin Monteath / Adelie Penguin (Pygoscelis adeliae) group diving from icefloe in Hope Bay, Antarctic Peninsula, Antarctica

Norbert Wu / Ice floes that have broken off sea ice edge in late summer, coast guard icebreaker in background, McMurdo Sound, Antarctica

Jim Brandenburg / Arctic Wolf (Canis lupus) on ice floe, Ellesmere Island, Nunavut, Canada

Tui De Roy / Adelie Penguin (Pygoscelis adeliae) group crowding on melting summer ice floe, Possession Island, Ross Sea, Antarctica

Tui De Roy / Adelie Penguin (Pygoscelis adeliae) group crowding on melting summer ice floe, Possession Island, Ross Sea, Antarctica

Flip Nicklin / Polar Bear (Ursus maritimus) about to haul out on ice floe, Wager Bay, Canada

Jim Brandenburg / Arctic Wolf (Canis lupus) leaping onto ice floe, Ellesmere Island, Nunavut, Canada

Jim Brandenburg / Arctic Wolf (Canis lupus) on ice floe, Ellesmere Island, Nunavut, Canada