Polar (main)
From The Encyclopedia of Earth
Polar
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Featured Article 
Penguins: Endangered by Melting IceRising temperatures and loss of snowpack or ice caps endangers a number of alpine and arctic species, including penguins. At the Antarctic, several species of penguins that... More »
- Featured Article
Polar Bears: Struggling in the Warming ArcticThe polar bear is one of the world’s largest carnivores. It inhabits the ice-covered waters of the circumpolar Arctic, particularly annual ice over the continental shelf... More »
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Penguins: Endangered by Melting Ice Last Updated on 2010-12-16 00:00:00 Rising temperatures and loss of snowpack or ice caps endangers a number of alpine and arctic species, including penguins. At the Antarctic, several species of penguins that depend on sea ice are experiencing population changes [1]; Colonies of Adélie penguins are declining at warmer sites, such as Anvers and King George Island, but expanding at colder sites such as Cape Royds on the Ross Sea. This indicates that populations of Adélie penguin are shifting location. [2] Emperor penguins also depend on sea ice, and their colony at Point Geologie is declining. Both Adélie penguins and emperor penguins nest near Point Geologie, but at different times of the year. Temperatures at this site have remained relatively constant over the past 50 years, while the extent of sea ice has diminished 66%. [3] The date of the penguins’ arrival at the site has remained... More » 
Polar Bears: Struggling in the Warming Arctic Last Updated on 2010-12-16 00:00:00 The polar bear is one of the world’s largest carnivores. It inhabits the ice-covered waters of the circumpolar Arctic, particularly annual ice over the continental shelf where biological productivity is highest. For most of the year, polar bears hunt seals from sea ice. [1] Bears optimize foraging for seals by staking out seal breathing holes and haul-out sites. Rarely do they capture seals in open water. During ice-free periods, female polar bears swim to shore from the southern edge of the pack ice and give birth on land, in dens. Recession of the Arctic ice cap as a result of warmer Arctic temperatures have extended the distance between denning and feeding sites. This increases the vulnerability of mothers and cubs. Polar bears, when on land, mostly scavenge along the shore for food other than seals. A longer ice-free period means more time on land and... More » 
