S Polar continent, area nearly 15·5 million km²/6 million sq mi; surrounded by ice-filled ring of ocean waters containing scattered island groups; mainly S of 65°S, almost entirely within the Antarctic Circle; c.22 400 km/14 000 mi coastline, mainly of high ice cliffs; indented by Ross and Weddell Seas; divided into Greater and Lesser Antarctica, separated by the Transantarctic Mts, highest point 4897 m/16 066 ft at Vinson Massif; no permanent population; no flowering plants, grasses, large land mammals; species of algae, moss, lichen, and sea plankton provide food for fish, birds, whales, and seals; average depth of surface ice sheet 1500 m/5000 ft, overlying rock; inland ice moves slowly towards the periphery, pushing long tongues into the sea and creating shelf ice over large areas; drift ice develops along the whole coastline; many icebergs in adjacent waters, the largest of the tabular type (1060 m/30200 ft high); movement of pack ice varies widely in different longitudes; outward blowing winds prevail, often of hurricane force; blizzards common, especially in autumn and winter; lowest temperature on Earth (?88·3°C) recorded at Vostok Station; major scientific explorations since first winter base established in 1899 by Borchgevrink; during International Geophysical Year (19578) 12 countries maintained 65 bases in Antarctica; Antarctic Treaty signed by these nations in 1959, providing for international co-operation in scientific research, and prohibiting military operations, nuclear explosions, and disposal of radioactive waste; 50-year ban on mining and mineral extraction, 1991; territorial claims made by the UK (British Antarctic Territory), Norway (Dronning Maud Land), France (Terre Adélie), Australia (Enderby Land, Wilkes Land, George V Coast, part of Oates Coast), New Zealand (160°E to 150°W), Chile (90°W to 53°W), and Argentina (74°W to 25°W); South Pole first reached by Amundsen in 1911; major iceberg losses in Antarctic Peninsula, through global warming, 1987, 1995, 1998, 2000, 2002.
font-size: 95%;">| (Antarctic Treaty Secretariat emblem) | |
| Area | 14,000,000 km² (5,405,430 mi²) (280,000 km² (108,108 mi²) ice-free, 13,720,000 km² (5,297,321 mi²) ice-covered) |
| Population | ~1000 (none permanent) |
|
Government – Executive Secretary |
governed by the Antarctic Treaty System Johannes Huber |
| Partial Territorial claims (frozen) |
Argentina Australia Chile France New Zealand Norway United Kingdom |
| Reserved the right to make claims |
Russia United States |
| Internet TLD | .aq |
| Calling Code | +672 |
Antarctica is the southernmost continent and includes the South Pole. At 14.425 million km², Antarctica is the third-smallest continent after Europe and Australia; There are no permanent human residents and Antarctica has never had an indigenous population. The name "Antarctica" comes from the Greek ανταρκτικός (antarktikos), meaning "opposite the Arctic."
Although myths and speculation about a Terra Australis ("Southern Land") date back to antiquity, the first confirmed sighting of the continent is commonly accepted to have occurred in 1820 by the Russian expedition of Mikhail Lazarev and Fabian Gottlieb von Bellingshausen.
The Antarctic Treaty was signed in 1959 by 12 countries.
History
Belief in the existence of a Terra Australis — a vast continent located in the far south of the globe to "balance" the northern lands of Europe, Asia and north Africa — had existed since Ptolemy suggested the idea in order to preserve symmetry of landmass in the world. Even in the late 17th century, after explorers had found that South America and Australia were not part of "Antarctica," geographers believed that the continent was much larger than its actual size.
European maps continued to show this land until Captain James Cook's ships, HMS Resolution and Adventure, crossed the Antarctic Circle on January 17, 1773 and again in 1774. The first confirmed sighting of Antarctica can be narrowed down to the crews of ships captained by three individuals. According to various organizations (the National Science Foundation, NASA, the University of California, San Diego, and other sources), ships captained by three men sighted Antarctica in 1820: Fabian von Bellingshausen (a captain in the Russian Imperial Navy), Edward Bransfield (a captain in the British Navy), and Nathaniel Palmer (an American sealer out of Stonington, Connecticut). Von Bellingshausen supposedly saw Antarctica on January 27, 1820, three days before Bransfield sighted land, and ten months before Palmer did so in November 1820.
In 1841, explorer James Clark Ross passed through what is now known as the Ross Sea and discovered Ross Island.
During an expedition led by Ernest Shackleton in 1907, parties led by T.
Richard Evelyn Byrd led several voyages to the Antarctic by plane in the 1930s and 1940s.
Geography
Most of Antarctica is located south of the Antarctic Circle, surrounded by the Southern Ocean. The coastline measures 17 968 km (11,160 miles) and is mostly characterized by ice formations, as the following table shows:
Coastal types around Antarctica (Drewry, 1983)| Type | Frequency |
|---|---|
| Ice shelf (floating ice front) | 44% |
| Ice walls (resting on ground) | 38% |
| Ice stream/outlet glacier (ice front or ice wall) | 13% |
| Rock | 5% |
| Total | 100% |
Physically, it is divided in two by the Transantarctic Mountains close to the neck between the Ross Sea and the Weddell Sea. The portion west of the Weddell Sea and east of the Ross Sea is called Western Antarctica and the remainder Eastern Antarctica, because they roughly correspond to the Western and Eastern Hemispheres relative to the Greenwich meridian.
About 98% of Antarctica is covered by the Antarctic ice sheet.
Western Antarctica is covered by the West Antarctic Ice Sheet. Several Antarctic ice streams, which account for about 10% of the ice sheet, flow to one of the many Antarctic ice shelves.
Vinson Massif, the highest peak in Antarctica at 4892 meters (16,050 feet), is located in the Ellsworth Mountains. Although Antarctica is home to many volcanoes, only Mt.
Antarctica is home to more than 70 lakes that lie thousands of meters under the surface of the continental ice sheet.
See also: Extreme points of Antarctica, Antarctic territories, and List of antarctic and sub-antarctic islandsGeology
Geological history and paleontology
More than 170 million years ago, Antarctica was part of the supercontinent Gondwana. Over time Gondwana broke apart and Antarctica as we know it today was formed around 25 million years ago.
Paleozoic era (540-250 Mya)
During the Cambrian period Gondwana had a mild climate. West Antarctica was partially in the northern hemisphere, and during this period large amounts of sandstones, limestones and shales were deposited. East Antarctica was at the equator, where sea-floor invertebrates and trilobites flourished in the tropical seas.
Mesozoic era (250-65 Mya)
As a result of continued warming, the polar ice caps melted and much of Gondwana became a desert. In East Antarctica the seed fern became established, and large amounts of sandstone and shale were laid down at this time. In West Antarctica conifer forests dominated through the entire Cretaceous period (146-65 Mya), though Southern beech began to take over at the end of this period. Ammonites were common in the seas around Antarctica, and dinosaurs were also present, though only two Antarctic dinosaur species (Cryolophosaurus and Antarctopelta) have been described to date.
Gondwana breakup (160-23 Mya)
Africa separated from Antarctica around 160 Mya, followed by India in the early Cretaceous (about 125 Mya). About 65 Mya, Antarctica (then connected to Australia) still had a tropical to subtropical climate, complete with a marsupial fauna. About 40 Mya Australia-New Guinea separated from Antarctica and the first ice began to appear. Around 23 Mya, the Drake Passage between Antarctica and South America resulted in the Antarctic Circumpolar Current.
Geology of present-day Antarctica
The geological study of Antarctica has been greatly hindered by the fact that nearly all of the continent is permanently covered with a thick layer of ice.
Geologically, West Antarctica closely resembles the Andes of South America. The most common rocks in West Antarctica are andesite and rhyolite volcanics formed during the Jurassic Period. The only anomalous area of West Antarctica is the Ellsworth Mountains region, where the stratigraphy is more similar to the eastern part of the continent.
East Antarctica is geologically very old, dating from the Precambrian era, with some rocks formed more than 3 billion years ago.
The main mineral resource known on the continent is coal. The most valuable resources of Antarctica lie offshore, namely the oil and natural gas fields found in the Ross Sea in 1973.
Climate
Antarctica is the coldest place on Earth. Eastern Antarctica is colder than its western counterpart because of higher elevation.
At the edge of the continent, strong katabatic winds off the polar plateau often blow at storm force.
Antarctica is colder than the Arctic for two reasons. Second, the Arctic Ocean covers the north polar zone: the ocean's relative warmth is transferred through the icepack and prevents temperatures in the Arctic regions from reaching the extremes typical of the land surface of Antarctica.
Given the latitude, long periods of constant darkness or constant sunlight create climates unfamiliar to human beings in much of the rest of the world.
Tabletop icebergs in Antarctica.Population
See also: Demographics of AntarcticaAntarctica has no permanent residents, but a number of governments maintain permanent research stations throughout the continent.
The first semi-permanent inhabitants of regions near Antarctica (areas situated south of the Antarctic Convergence) were English and American sealers who used to spend a year or more on South Georgia, from 1786 onward.
The first child born in the southern polar region was Norwegian girl Solveig Gunbjörg Jacobsen, born in Grytviken on 8 October 1913, and her birth registered by the resident British Magistrate of South Georgia.
Emilio Marcos Palma was the first person born on the Antarctic mainland, at Base Esperanza in 1978, his parents being sent there along with seven other families by the Argentinean government to determine if family life was suitable in the continent. In 1986, Juan Pablo Camacho was born at the Presidente Eduardo Frei Montalva Base, becoming the first Chilean born in Antarctica.
Flora and fauna
See also: Antarctica ecozoneFlora
The climate of Antarctica does not allow extensive vegetation.
There are more than 200 species of lichens and approximately 50 species of bryophytes, such as mosses. There are two species of flowering plants found in the Antarctic Peninsula: Deschampsia antarctica (Antarctic hair grass) and Colobanthus quitensis (Antarctic pearlwort).
Fauna
Land fauna is nearly completely invertebrate. The midge, just 12 mm in size, is the largest land animal in Antarctica. The Snow Petrel is one of only three birds that breed exclusively in Antarctica and have been seen at the South Pole.
A variety of marine animals exist and rely, directly or indirectly, on the phytoplankton. The Emperor penguin is the only penguin that breeds during the winter in Antarctica, while the Adélie Penguin breeds farther south than any other penguin.
The Antarctic fur seal was very heavily hunted in the 18th and 19th centuries for its pelt by sealers from the United States and the United Kingdom. Antarctic krill, which congregates in large schools, is the keystone species of the ecosystem of the Southern Ocean, and is an important food organism for whales, seals, leopard seals, fur seals, squid, icefish, penguins, albatrosses and many other birds.
The passing of the Antarctic Conservation Act brought several restrictions to the continent. The Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR), a treaty that came into force in 1980, requires that regulations managing all Southern Ocean fisheries consider potential effects on the entire Antarctic ecosystem.
Politics
As the only uninhabited continent, Antarctica has no government and belongs to no country. The area between 90°W and 150°W is the only part of Antarctica, indeed the only solid land on Earth, not claimed by any country.
Since 1959, claims on Antarctica have been suspended and the continent is considered politically neutral. For the purposes of the Treaty System, Antarctica is defined as all land and ice shelves south of 60°S. It set aside Antarctica as a scientific preserve, established freedom of scientific investigation, environmental protection, and banned military activity on that continent.
The Antarctic Treaty prohibits any military activity in Antarctica, such as the establishment of military bases and fortifications, the carrying out of military manoeuvres, or the testing of any type of weapon.
The United States military issues the Antarctica Service Medal to military members or civilians who perform research duty on the Antarctica continent. The medal includes a "wintered over" bar issued to those who remain on the continent for two complete six-month seasons.Unlike other states, the United States has made no territorial claim in Antarctica nor does it recognize the claims of any other state.
Antarctic territories
| Country | Territory | Claim limits | Date |
|---|---|---|---|
| Argentina | Argentine Antarctica | 25°W to 74°W | 1943 |
| Australia | Australian Antarctic Territory | 160°E to 142°2′W and 136°11′W to 44°38′E | 1933 |
| Chile | Antarctic Chilean Territory | 53°W to 90°W | 1940 |
| France | Adelie Land | 142°2′E to 136°11′E | 1924 |
| New Zealand | Ross Dependency | 150°W to 160°E | 1923 |
| Norway | Queen Maud Land | 44°38′E to 20°W | 1939 |
| Peter I Island | 68°50′S 90°35′W | 1929 | |
| United Kingdom | British Antarctic Territory | 20°W to 80°W | 1908 |
| NONE | Unclaimed territory | 90°W to 150°W |
The Argentine, British and Chilean claims all overlap.
Germany also maintained a claim to Antarctica, known as New Swabia, between 1939 and 1945.
Economy
Although coal, hydrocarbons, iron ore, platinum, copper, chromium, nickel, gold and other minerals have been found, they exist in quantities too small to exploit.
Small-scale tourism has existed since 1957 and is currently self-regulated by International Association of Antarctic Tour Operators (IAATO). Several ships transport people into Antarctica for specific scenic locations.
Transport
Transport on the continent has transformed from heroic explorers crossing the isolated remote area of Antarctica by foot to a more open area due to human technologies enabling more convenient and faster transport by land and predominantly air and water.
Research
See also: List of research stations in AntarcticaEach year, scientists from 27 different nations conduct experiments not reproducible in any other place in the world.
Researchers include biologists, geologists, oceanographers, physicists, astronomers, glaciologists, and meteorologists. Glaciologists in Antarctica are concerned with the study of the history and dynamics of floating ice, seasonal snow, glaciers, and ice sheets.
Since the 1970s an important focus of study has been the ozone layer in the atmosphere above Antarctica.
Meteorites
Meteorites from Antarctica are an important area of study of material formed early in the solar system; The first meteorites found in Antarctica were in 1912. In 1969 the Japanese discovered nine meteorites in Antarctica.
This large collection of meteorites allows a better understanding of the abundance of meteorite types in the solar system and how meteorites relate to asteroids and comets.
In 2006 a team of researchers from Ohio State University used gravity measurements by NASA's GRACE satellites to discover the 300-mile-wide Wilkes Land crater, which probably formed about 250 million years ago.
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