Steven Kazlowski / Polar bear (Ursus maritimus) mother with cub, newly emerged from their den on the Arctic coast, eastern Arctic National Wildlife Refuge, Alaska

Yva Momatiuk & John Eastcott / Heather (Calluna sp) flowering in tundra, Skaftafell National Park, Iceland

Yva Momatiuk & John Eastcott / Waterfall and basalt columns, Svartifoss Waterfall, Skaftafell National Park, Iceland

Yva Momatiuk & John Eastcott / Ice climber scaling Skaftafellsjokull Glacier, Skaftafell National Park, Iceland

Yva Momatiuk & John Eastcott / Ice climbers atop Skaftafellsjokull Glacier, Skaftafell National Park, Iceland

Yva Momatiuk & John Eastcott / Ice climber scaling Skaftafellsjokull Glacier, Skaftafell National Park, Iceland

Eric Baccega / Female Polar bear (Ursus maritimus) grooming, with two cubs playing nearby, Wapusk National Park, Manitoba, Canada, February.

Steven Kazlowski / Polar bear (Ursus maritimus) silhouetted against setting sun, Bernard Spit, off the 1002 Area, Arctic National Wildlife Refuge, North Slope, Alaska, USA, October. Vulnerable species.

Steven Kazlowski / Polar bear (Ursus maritimus) portrait against sky at sunset, Bernard Spit, off the 1002 Area, Arctic National Wildlife Refuge, North Slope, Alaska, USA, September. Vulnerable species.

Orsolya Haarberg / Snow covered Norway spruce (Picea abies) trees at the treeline, Stubba Nature Reserve, Laponia, Sweden, February 2013.

Erlend Haarberg / Rock face reflected in lake surface with floating blue ice sheets, Ovre Pikhaugvatnet lake, Glomdalen valley, Saltfjellet-Svartisen National Park, Norway, August 2015.

Erlend Haarberg / Woman pulling a sledge up a slope, Rapadalen, Sarek National Park, Laponia, Sweden, March 2015.