Steven Kazlowski / Adult Polar bear (Ursus maritimus) taking refuge and resting in icy eroding permafrost while waiting for fall freeze up, 1002 coastal plain of Arctic National Wildlife Refuge, Alaska, USA. October 201...

Marie Read / Loggerhead shrike (Lanius ludovicianus) on an ice-covered fence after an ice storm, Anahuac National Wildlife Refuge, Texas, USA. January.

Guy Edwardes / Buachaille Etive Mor in winter, Rannoch Moor, Highlands, Scotland, UK. January 2015.

Rolf Nussbaumer / White-winged Dove (Zenaida asiatica), adult perched on icy branch of Yaupon Holly (Ilex vomitoria), Hill Country, Texas, USA. February

Rolf Nussbaumer / White-winged Dove (Zenaida asiatica), adult perched on icy branch of Yaupon Holly (Ilex vomitoria), Hill Country, Texas, USA. February

Sven Zacek / Pink algae in fresh snow on the coast of the Baltic Sea, Lahemaa National Park, Northern Estonia. December 2012.

David Pattyn / Alpine ibex (Capra ibex) male in deep snow with icicles behind, Gran Paradiso National Park, Italy. December

Bryan and Cherry Alexander / Icicles hanging from the edge of a small blue iceberg as the summer thaw sets in, Antarctica

Olga Kamenskaya / Ice splash out formation with icicles, Lake Baikal, Siberia, Russia, March

Ben Cranke,Ben Cranke / Gentoo Penguin (Pygoscelis papua) group travelling out to sea, Cuverville Island, Antarctic Peninsula, Antarctica

Sandra Bartocha / Light reflected through icicles, Tollensesee, Germany, January

Chadden Hunter / Brinicles (brine icicles or ice stalactites) forming under the ice, growing towards the sea floor, Ross Sea, McMurdo Sound, Antarctica. Taken on location for 'Winter' episode of the BBC Frozen Planet...

Brent Stephenson / A large hole in an iceberg with icicles hanging. Yalour Islands, Antarctic Peninsula, Antarctica, December.

Chadden Hunter / Person standing infront of long icicles, outside volcanic ice cave, Mount Erebus, Antarctica. Taken on location for BBC Frozen Planet series, 2009

Bryan and Cherry Alexander / Icicles at entrance to cave in a small iceberg, Antarctica, 2009.

Gary K. Smith / Icicles hanging from on greenhouse roof, Norfolk, UK, December 2009

Thomas Lazar / Ice hanging from arch in sea cave carved in soft sandstone cliffs, frozen lake, Squaw Bay, Lake Superior, Apostle Islands National Lakeshore, Wisconsin, USA, February 2009

Bryan and Cherry Alexander / Thawing slabs of sea ice in summer, Northwest Greenland, 1980.

Bryan and Cherry Alexander / Icicles hanging in interior of melting iceberg. Thule, Northwest Greenland, 1980.

Bryan and Cherry Alexander / Icicles hanging from a ledge on an iceberg, Antarctica, October 2006.

Sue Flood / Ross Ice Shelf, Antarctica, December 2008

Andrew Walmsley / Icicles on grass at Mount Hutt, Christchurch, New Zealand, July 2008

Wild Wonders of Europe / Radisics / Ice formation in Ledena Pecina (an ice cave) inside Obla Glava (Rounded head peak) Durmitor NP, Montenegro, October 2008

Wild Wonders of Europe / Radisics / Ice forming stalagmite structures in Ledena Pecina (an ice cave) inside Obla Glava (Rounded head peak) Durmitor NP, Montenegro, October 2008

Wild Wonders of Europe / Radisic / Ice forming stalagmite structures in Ledena Pecina (an ice cave) inside Obla Glava (Rounded head peak) Durmitor NP, Montenegro, October 2008

Guy Edwardes / Icicles on frozen Slap Pericnik, Vrata Valley, Gorenjska, Triglavski National Park, Julian Alps, Slovenia, January 2006

Wild Wonders of Europe / E Haarberg / Frozen waterfall, Gran Paradiso National Park, Italy, November 2008

John Cancalosi / Taughannock Falls, frozen, Taughannock Falls State Park, New York, USA

Pete Oxford / Nature Picture Library photographer Pete Oxford at -40 C Darkhad depression, Mongolia - icicles forming on eyelashes and hair 2002

Doug Allan / Icicles on pack ice melting, Canadian Arctic

Ingo Arndt / Close up of icicles hanging from log over stream, Hessen, Germany. February.

Shane Gross / Icicles forming on melting iceberg, Weddell Sea, Antarctica, November, 2021.

Ashley Cooper / Icicles on Low Water Beck waterfall, frozen in winter, Lake District National Park, Cumbria, UK. February.

Ashley Cooper / Overhanging wind blown Icicles on Low Water Beck waterfall, frozen in winter, Lake District National Park, Cumbria, UK. February, 2021.

Ashley Cooper / Icicles over stream on Bright Beck, Langdale, Lake District National Park, Cumbria, UK. February, 2021.

Ashley Cooper / Ice climber climbing up a frozen waterfall at Launchy Ghyll, Thirlmere, Lake District National Park, Cumbria, UK. February, 2021.

Ashley Cooper / Ice climber preparing to climb frozen waterfall on Whorneyside Force below Crinkle Crags, Lake District National Park, Cumbria, UK. February, 2021.

Ashley Cooper / Icicles on Low Water Beck waterfall, frozen in winter, Lake District National Park, Cumbria, UK. February.

Tony Wu / Long-tailed tit (Aegithalos caudatus) feeding, hovering in front of an icicle formed from the sap of a painted maple tree (Acer pictum). Hokkaido, Japan.

Alex Hyde / Tunnel along the Monsal Trail with a dramatic display of icicles during an extended period of freezing weather, Peak District National Park, Derbyshire, UK. February.

Alex Hyde / Tunnel along the Monsal Trail with a dramatic display of icicles during an extended period of freezing weather, Peak District National Park, Derbyshire, UK. February.

Andy Sands / Speed camera covered in icicles from splashed flood water, Hertfordshire, England, UK, February

Andy Sands / Road covered in icicles from splashed flood water, Hertfordshire, England, UK, February

Andy Sands / Icicles hanging from Rose hips in snow, Hertfordshire, England, UK, February

Ashley Cooper / Icicles in snow pack. Beagle Island, Danger Islands, Antarctica. December.

Ashley Cooper / Adelie penguin (Pygoscelis adeliae) group, part of colony that nests on Beagle Island, Danger Islands, Antarctica. December 2019.

Ashley Cooper / Icicles hanging on side of iceberg, melting due to climate change. Weddell Sea, Antarctica. December 2019.

Ashley Cooper / Curves on edge of iceberg in Southern Ocean. One of the most rapidly warming areas on the planet. Spert Island, Palmer Archipelago, Antarctica. December 2019.