Antarctic Peninsula

Antarctic Peninsula

Antarctic Peninsula, glaciated mountain region of W Antarctica, extending c.1,200 mi (1,930 km) N toward South America; in the south, volcanic peaks rise to c.11,000 ft (3,350 m). Most of its NE coast is fringed by the Larsen ice shelf. The peninsula is surrounded by numerous islands, including the South Shetlands and the Palmer Archipelago. The tip of the peninsula, 670 mi (1,078 km) from Cape Horn, is Antarctica's farthest point from the South Pole. The continent's only flowering plants are found on the peninsula.

The northwest coast of the peninsula is believed to have been mapped by the British navigator Edward Bransfield in Jan., 1820, and was explored by sealers in 1820-21. First considered to be part of the continent, the peninsula was later (1928) thought to be a group of islands; the John Rymill expedition (1934-37) proved its peninsularity. It was originally named Palmer Peninsula by Americans for Nathaniel Palmer, a U.S. captain who explored the area in Nov., 1820. In 1832, Britain claimed it and called it Graham Land and Trinity Peninsula. Argentina claimed it in 1940 as San Martin Land and Chile in 1942 as O'Higgins Land. In 1964, by international agreement, the entire feature was called the Antarctic Peninsula; Graham Land, Trinity Peninsula, and Palmer Land are used as local names.

The peninsula is now the site of numerous research stations. The disintegration of a Rhode Island-sized section of the Larsen ice shelf over a few weeks time in 2002, although directly due to locally warmer temperatures, was also regarded by some scientists as a result of the more general global warming. It was the largest of several ice shelves on the peninsula that have retreated since the 1960s.

The Antarctic Peninsula is the northernmost part of the mainland of Antarctica, and almost the only part of that continent that extends outside the Antarctic Circle. It lies in the Western Hemisphere, facing South America, making it a part of West Antarctica. It extends from a line between Cape Adams (Weddell Sea) and a point on the mainland south of Eklund Islands, to Prime Head.

The Antarctic Peninsula is important because research has revealed that the forces of climate change are having a great effect on the region. The remote polar position has resulted in the area being dotted with numerous research stations and multiple claims of sovereignty. The peninsula forms part of claims by the Argentine Antarctica, British Antarctic Territory and Chilean Antarctic Territory although the exact boundaries of each claim are still disputed

History

Discovery and naming

The first sighting of Antarctic Peninsula is contested but apparently occurred in the 1820s. Agreement on this name by the US-ACAN and UK-APC in 1964 resolved a long-standing difference over the use of the American name "Palmer Peninsula" or the British name "Graham Land" for this feature. (Graham Land is now that part of the Antarctic Peninsula northward of a line between Cape Jeremy and Cape Agassiz, whilst Palmer Land is the part southward of that line. Palmer Land is named for the American seal hunter, Nathaniel Palmer.) In Chile, the peninsula is officially referred as O'Higgins Land, after the Chilean patriot and Antarctic visionary. Other Spanish countries call it "Península Antártica", among them Argentina (while also calling it "Tierra de San Martín"), which has more bases and personnel there than any other nation.

Other portions of the peninsula that were named upon discovery include Bowman Coast, Black Coast, Danco Coast, Davis Coast, English Coast, Fallieres Coast, Loubet Land, Nordenskjold Coast and the Wilkins Coast.

Recent

Argentina's Esperanza Base was the birthplace of Emilio Marcos Palma, the first person to be born in Antarctica.

The dinosaur species Antarctopelta was the first dinosaur fossil to be found on the continent, in January 1986 on James Ross Island, off the Antarctic Peninsula.

The grounding of the Argentine ship Bahia Paraiso and subsequent 170,000 gallon oil spill occurred near the Antarctic Peninsula in 1989.

Geography

The peninsula is highly mountainous, its highest peaks rising to approximately 2,800 metres (9,186 ft). Notable peaks on the peninsula include Mount Castro, Mount Coman, Mount Gilbert, Mount Jackson, Mount William, Mount Owen and Mount Scott. These mountains are considered to be a continuation of the Andes of South America, with a submarine spine connecting the two. That is an argument advanced by Chile and Argentina for their territorial claims.

The landscape of the peninsula is typical Antarctic tundra. The peninsula has a sharp elevation gradient, with glaciers flowing into the Larsen Ice Shelf, which experienced significant breakup in 2002. Other ice shelfs on the peninsular include George VI Ice Shelf, Wilkins Ice Shelf, Wordie Ice Shelf and the Bach Ice Shelf. The Filchner-Ronne Ice Shelf lies to the east of the peninsula.

Separating the peninsula from nearby islands is the Antarctic Sound, Erebus and Terror Gulf, George VI Sound, Gerlache Strait and the Lemaire Channel. Further to the west lies the Bellingshausen Sea and in the north is the Scotia Sea. The Antarctic Peninsula and Cape Horn create a funneling effect, which channels the winds into the relatively narrow Drake Passage. Hope Bay, at , is near to the northernmost extremity of the peninsula, which is Prime Head, at 63º13'S.

Climate change

The Antarctic Peninsula is a part of the world that is experiencing extraordinary warming. Each decade for the last five, average temperatures in the Antarctic Peninsula have risen by half a degree Celsius. Ice mass loss on the peninsula occurred at a rate of 60 billion tonnes in 2006, with the greatest change occurring in the northern tip of the peninsula. Seven ice shelves along the Antarctic Peninsula have retreated or disintegrated in the last two decades. According to a study by the British Antarctic Survey, glaciers on the peninsula are not only retreating but also increasing their flow rate as a result of increased bouyancy in the lower parts of the glaciers. Professor David Vaughan has described the disintegration of the Wilkins Ice Shelf as the latest evidence of rapid warming in the area. The Intergovernmental Panel on Climate Change has been unable to determine the greatest potential effect on sea level rise that glaciers in the region may cause.

Research stations

Since the peninsula has the mildest climate in Antarctica, the highest concentration of research stations on the continent can be found there, or on the many nearby islands, and is the part of Antarctica most often visited by tour vessels and yachts. Occupied bases include Base General Bernardo O'Higgins Riquelme, Bellingshausen Station, Comandante Ferraz Brazilian Antarctic Base, Rothera Research Station and San Martín Base. Today, on the Antarctic Peninsula there are many abandoned scientific and military bases. Ice core and sediment samples from the peninsula are valuable because events such as the Little Ice Age can be verified with samples from other continents.

Flora and Fauna

Antarctica's two flowering plant species, the Antarctic hair grass (Deschampsia antarctica) and Antarctic pearlwort (Colobanthus quitensis) are found on the northern and western parts of the Antarctic Peninsula.

See also

References

External links

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