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West Antarctica, orLesser Antarctica, one of the two major regions ofAntarctica, is the part of that continent that lies within theWestern Hemisphere, and includes theAntarctic Peninsula. It is separated fromEast Antarctica by theTransantarctic Mountains and is covered by theWest Antarctic Ice Sheet. It lies between theRoss Sea (partly covered by theRoss Ice Shelf), and theWeddell Sea (largely covered by theFilchner-Ronne Ice Shelf). It may be considered a giantpeninsula, stretching from theSouth Pole towards the tip of South America.
West Antarctica is largely covered by theAntarctic ice sheet, but there have been signs thatclimate change is having some effect and that this ice sheet may have started to shrink slightly. Over the past 50 years, the west coast of the Antarctic Peninsula has been – and still is – one of the most rapidly warming parts of the planet,[1][2] and the coasts of the Peninsula are the only parts of West Antarctica that become (in summer) ice-free. These constitute theMarielandia Antarctic tundra and have the warmest climate in Antarctica. The rocks are clad inmosses andlichens that can cope with the intense cold of winter and the short growing-season.
Lying on thePacific Ocean side of the Transantarctic Mountains, West Antarctica comprises theAntarctic Peninsula (withGraham Land andPalmer Land) andEllsworth Land,Marie Byrd Land andKing Edward VII Land, offshore islands such asAdelaide Island, andice shelves, notably theFilchner-Ronne Ice Shelf on theWeddell Sea, and theRoss Ice Shelf on theRoss Sea.
West Antarctica was named in the early 20th century.[3] That usage became standard following theInternational Geophysical Year (1957–1958) and explorations which disclosed that the Transantarctic Mountains provide a useful regional border between West Antarctica andEast Antarctica. TheAdvisory Committee on Antarctic Names approved the name in 1962.
West Antarctica is mostly covered by a massive ice sheet referred to as theWest Antarctic Ice Sheet. In recent decades, thisice sheet has shown signs of decreasing mass.[4]
The geologic history of West Antarctica was summarized in a 2020 publication.[5]
The parts of West Antarctica not covered with ice (Antarctic oasis), which are the coasts of theAntarctic Peninsula, constitute abiodiversity region known as Marielandia Antarctictundra (afterMarie Byrd Land).[6] This area has the warmestclimate in Antarctica and themoss andlichen-covered rocks are free of snow during the summer months, although the weather is still intensely cold and the growing season very short.
This article incorporatespublic domain material from"West Antarctica".Geographic Names Information System.United States Geological Survey.
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