West Antarctica, or Lesser Antarctica, one of the two major regions of Antarctica, is the part of the continent that lies within the Western Hemisphere including the Antarctic Peninsula.
Lying on the Pacific Ocean side of the Transantarctic Mountains, West Antarctica comprises the Antarctic Peninsula (with Graham Land and Palmer Land) and Ellsworth Land, Marie Byrd Land and King Edward VII Land and offshore islands such as Adelaide Island, the Filchner-Ronne Ice Shelf on the Weddell Sea, and the Ross Ice Shelf on the Ross Sea. West Antarctica is separated from the main land mass of the continent by the icy waters of the Ross Sea and Weddell Sea, and resembles a giant peninsula that stretches roughly from the South Pole towards the southern tip of South America.
The name has existed for more than 100 years (Balch, 1902; Nordenskiöld, 1905), but its greatest use followed the International Geophysical Year (1957-58) and explorations disclosing that the Transantarctic Mountains provide a useful regional separation of West Antarctica and East Antarctica. The name was approved by Advisory Committee on Antarctic Names (US-ACAN) in 1962.
West Antarctica is mostly covered by a massive ice sheet referred to as the West Antarctic Ice Sheet (WAIS). This ice sheet has shown signs of decreasing mass.[1]
The parts of West Antarctica not covered with ice (Antarctic oasis), which are the coasts of the Antarctic Peninsula, constitute a biodiversity region known as Marielandia Antarctic tundra (after Marie Byrd Land). [2] This area has the mildest climate in Antarctica and the moss and lichen-covered rocks are free of snow during the summer months, although the weather is still intensely cold and the growing season very short.
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This article incorporates public domain material from the United States Geological Survey document "West Antarctica" (content from the Geographic Names Information System).