Antarctica (/ænˈtɑːrktɪkə/ⓘ)[note 1] is
Earth's southernmost and least-populated
continent. Situated almost entirely south of the
Antarctic Circle and surrounded by the
Southern Ocean (also known as the
Antarctic Ocean), it contains the geographic
South Pole. Antarctica is the fifth-largest continent, being about 40% larger than
Europe, and has an area of 14,200,000 km2 (5,500,000 sq mi). Most of Antarctica is covered by the
Antarctic ice sheet, with an average thickness of 1.9 km (1.2 mi).
Antarctica is, on average, the coldest, driest, and windiest of the continents, and it has the highest average
elevation. It is mainly a
polar desert, with annual
precipitation of over 200 mm (8 in) along the coast and far less inland. About 70% of the world's
freshwater reserves are frozen in Antarctica, which, if melted, would raise global
sea levels by almost 60 metres (200 ft). Antarctica holds the record for the
lowest measured temperature on Earth, −89.2 °C (−128.6 °F). The coastal regions can reach temperatures over 10 °C (50 °F) in the summer. Native
species of animals include
mites,
nematodes,
penguins,
seals and
tardigrades. Where
vegetation occurs, it is mostly in the form of
lichen or
moss.
The name given to the continent
originates from the word antarctic, which comes from
Middle Frenchantartique or antarctique ('opposite to the
Arctic') and, in turn, the
Latinantarcticus ('opposite to the north'). Antarcticus is derived from the
Greekἀντι- ('anti-') and ἀρκτικός ('of
the Bear', 'northern').[5] The Greek philosopher
Aristotle wrote in Meteorology about an "Antarctic region" in
c. 350 BCE.[6] The Greek geographer
Marinus of Tyre reportedly used the name in his world map from the second century CE, now lost. The
Roman authors
Gaius Julius Hyginus and
Apuleius used for the South Pole the
romanised Greek name polus antarcticus,[7] from which derived the
Old Frenchpole antartike (modern pôle antarctique) attested in 1270, and from there the
Middle Englishpol antartik, found first in a
treatise written by the English author
Geoffrey Chaucer.[5]
Belief by Europeans in the existence of a Terra Australis—a vast continent in the far south of the globe to balance the northern lands of Europe, Asia, and North Africa—had existed as an intellectual concept since
classical antiquity. The belief in such a land lasted until the European
discovery of Australia.[8]
During the early 19th century, explorer
Matthew Flinders doubted the existence of a detached continent south of Australia (then called
New Holland) and thus advocated for the "Terra Australis" name to be used for Australia instead.[9][10] In 1824, the colonial authorities in
Sydney officially renamed the continent of New Holland to Australia, leaving the term "Terra Australis" unavailable as a reference to Antarctica. Over the following decades, geographers used phrases such as "the Antarctic Continent". They searched for a more poetic replacement, suggesting names such as Ultima and Antipodea.[11]Antarctica was adopted in the 1890s, with the first use of the name being attributed to the Scottish
cartographerJohn George Bartholomew.[12]
Positioned asymmetrically around the South Pole and largely south of the
Antarctic Circle (one of the five major
circles of latitude that mark maps of the world), Antarctica is surrounded by the
Southern Ocean.[note 2]Rivers exist in Antarctica; the longest is the
Onyx. Antarctica covers more than 14.2 million km2 (5,500,000 sq mi), almost double the area of Australia, making it the fifth-largest continent, and comparable to the surface area of
Pluto. Its coastline is almost 18,000 km (11,200 mi) long:[1] as of 1983[update], of the four coastal types, 44% of the coast is floating ice in the form of an
ice shelf, 38% consists of ice walls that rest on rock, 13% is
ice streams or the edge of glaciers, and the remaining 5% is exposed rock.[14]
The
lakes that lie at the base of the continental
ice sheet occur mainly in the
McMurdo Dry Valleys or various
oases.[15]Lake Vostok, discovered beneath Russia's
Vostok Station, is the largest
subglacial lake globally and one of the largest lakes in the world. It was once believed that the lake had been sealed off for millions of years, but scientists now estimate its water is replaced by the slow melting and freezing of ice caps every 13,000 years.[16] During the summer, the ice at the edges of the lakes can melt, and liquid moats temporarily form. Antarctica has both
saline and freshwater lakes.[15]
Vinson Massif, in the
Ellsworth Mountains, is the highest peak in Antarctica at 4,892 m (16,050 ft).[25] Mount Erebus on
Ross Island is the world's southernmost active
volcano and
erupts around 10 times each day. Ash from eruptions has been found 300 kilometres (190 mi) from the
volcanic crater.[26] There is evidence of a large number of volcanoes under the ice, which could pose a risk to the ice sheet if activity levels were to rise.[27] The ice dome known as
Dome Argus in East Antarctica is the highest Antarctic ice feature, at 4,091 metres (13,422 ft). It is one of the world's coldest and driest places—temperatures there may reach as low as −90 °C (−130 °F), and the annual precipitation is 1–3 cm (0.39–1.18 in).[28]
During the
Cambrian period, Gondwana had a mild climate.[32] West Antarctica was partially in the
Northern Hemisphere, and during the time, large amounts of
sandstones,
limestones, and
shales were deposited. East Antarctica was at the equator, where seafloor
invertebrates and
trilobites flourished in the tropical seas. By the start of the
Devonian period (416
Ma), Gondwana was in more southern latitudes, and the climate was cooler, though fossils of land plants are known from then. Sand and
silts were laid down in what is now the Ellsworth,
Horlick and
Pensacola Mountains.
Antarctica became glaciated during the
Late Paleozoic icehouse beginning at the end of the Devonian period (360 Ma), though glaciation would substantially increase during the late
Carboniferous. It drifted closer to the South Pole, and the climate cooled, though
flora remained.[33] After deglaciation during the latter half of the Early
Permian, the land became dominated by
glossopterids (an extinct group of seed plants with no close living relatives), most prominently Glossopteris, a tree interpreted as growing in waterlogged soils, which formed extensive coal deposits. Other plants found in Antarctica during the Permian include
Cordaitales,
sphenopsids, ferns, and
lycophytes.[34] At the end of the Permian, the climate became drier and hotter over much of Gondwana, and the
glossopterid forest ecosystems collapsed, as part of the
End-Permian mass extinction.[34][35] There is no evidence of any
tetrapods having lived in Antarctica during the Paleozoic.[36]
Mesozoic era (250–66 Ma)
The continued warming dried out much of Gondwana. During the Triassic, Antarctica was dominated by
seed ferns (pteridosperms) belonging to the genus Dicroidium, which grew as trees. Other associated Triassic flora included
ginkgophytes,
cycadophytes,
conifers, and sphenopsids.[37]Tetrapods first appeared in Antarctica during the early
Triassic, with the earliest known fossils found in the
Fremouw Formation of the Transantarctic Mountains.[36]Synapsids (also known as "mammal-like reptiles") included species such as Lystrosaurus, and were common during the
Early Triassic.[38]
Around 53 Ma, Australia-
New Guinea separated from Antarctica, opening the
Tasmanian Passage.[52] The
Drake Passage opened between Antarctica and South America around 30 Ma, resulting in the creation of the
Antarctic Circumpolar Current that completely isolated the continent.[53] Models of Antarctic geography suggest that this current, as well as a
feedback loop caused by lowering
CO2 levels, caused the creation of small yet permanent polar ice caps. As CO2 levels declined further the ice began to spread rapidly, replacing the forests that until then had covered Antarctica.[54]Tundra ecosystems continued to exist on Antarctica until around 14-10 million years ago, when further cooling lead to their extermination.[55]
West Antarctica was formed by the merging of several
continental plates, which created a number of mountain ranges in the region, the most prominent being the Ellsworth Mountains. The presence of the
West Antarctic Rift System has resulted in
volcanism along the border between West and East Antarctica, as well as the creation of the Transantarctic Mountains.[60]
East Antarctica is geologically varied. Its formation began during the
Archean Eon (4,000 Ma–2,500 Ma), and stopped during the Cambrian Period.[61] It is built on a
craton of rock, which is the basis of the Precambrian
Shield.[62] On top of the base are
coal and sandstones, limestones, and shales that were laid down during the Devonian and Jurassic periods to form the Transantarctic Mountains.[63] In coastal areas such as the
Shackleton Range and Victoria Land, some
faulting has occurred.[64][65]
Antarctica is the coldest, windiest, and driest of Earth's continents.[1]
Near the coast, the temperature can exceed 10 °C in summer and fall to below −40 °C in winter. Over the elevated inland, it can rise to about −30 °C in summer but fall below −80 °C in winter.
The lowest natural air temperature ever recorded on Earth was −89.2 °C (−128.6 °F) at the Russian Vostok Station in Antarctica on 21 July 1983.[69] A lower air temperature of −94.7 °C (−138.5 °F) was recorded in 2010 by satellite—however, it may have been influenced by ground temperatures and was not recorded at a height of 2 m (7 ft) above the surface as required for official air temperature records.[70][71]
Antarctica is a
polar desert with little
precipitation; the continent receives an average equivalent to about 150 mm (6 in) of water per year, mostly in the form of snow. The interior is dryer and receives less than 50 mm (2 in) per year, whereas the coastal regions typically receive more than 200 mm (8 in).[72] In a few
blue-ice areas, the wind and
sublimation remove more snow than is accumulated by precipitation.[73] In the dry valleys, the same effect occurs over a rock base, leading to a barren and
desiccated landscape.[74] Antarctica is colder than the
Arctic region, as much of Antarctica is over 3,000 m (9,800 ft) above sea level, where air temperatures are colder. The relative warmth of the
Arctic Ocean is transferred through the
Arctic sea ice and moderates temperatures in the Arctic region.[75]
Regional differences
East Antarctica is colder than its western counterpart because of its higher elevation.
Weather fronts rarely penetrate far into the continent, leaving the centre cold and dry, with moderate wind speeds. Heavy snowfalls are common on the coastal portion of Antarctica, where snowfalls of up to 1.22 m (48 in) in 48 hours have been recorded. At the continent's edge, strong
katabatic winds off of the
polar plateau often blow at
storm force. During the summer, more
solar radiation reaches the surface at the South Pole than at the
equator because of the 24 hours of sunlight received there each day.[1]
Climate change caused by
greenhouse gas emissions from human activities occurs everywhere on Earth, and while Antarctica is less vulnerable to it than any other continent,[77]climate change in Antarctica has already been observed. There has been an average temperature increase of >0.05 °C/decade since 1957 across the continent, although it had been uneven.[78] While
West Antarctica warmed by over 0.1 °C/decade from the 1950s to the 2000s and the exposed
Antarctic Peninsula has warmed by 3 °C (5.4 °F) since the mid-20th century,[79] the colder and more stable
East Antarctica had been experiencing cooling until the 2000s.[80][81] Around Antarctica, the
Southern Ocean has absorbed more
heat than any other ocean,[82] with particularly strong warming at depths below 2,000 m (6,600 ft)[83]: 1230 and around the West Antarctic, which has warmed by 1 °C (1.8 °F) since 1955.[79]
The warming of Antarctica's territorial waters has caused the weakening or outright collapse of
ice shelves, which float just offshore of
glaciers and stabilize them. Many coastal glaciers have been losing mass and retreating, which causes net annual ice loss across Antarctica,[83]: 1264 even as the
East Antarctic ice sheet continues to gain ice inland. By 2100, net ice loss from Antarctica alone is expected to add about 11 cm (5 in) to global
sea level rise. However,
marine ice sheet instability may cause West Antarctica to contribute tens of centimeters more if it is triggered before 2100.[83]: 1270 With higher warming instability would be much more likely, and could double overall 21st century sea level rise.[84][85][86]
The fresh
meltwater from the ice, 1100-1500 billion tons (GT) per year, dilutes the saline
Antarctic bottom water,[87][88] thus weakening the lower cell of the
Southern Ocean overturning circulation.[83]: 1240 Some research tentatively suggests a full collapse of the circulation may occur between 1.7 °C (3.1 °F) and 3 °C (5.4 °F) of global warming,[89] although the full effects are expected to unfold over multiple centuries. They include less
precipitation in the
Southern Hemisphere but more in the
Northern Hemisphere, and an eventual decline of
fisheries in the Southern Ocean with a potential
collapse of certain
marine ecosystems.[90] Furthermore, while many Antarctic species remain undiscovered, there are already documented increases in
flora and large
fauna such as
penguins are already seen struggling to retain suitable
habitat. On ice-free land,
permafrost thaws, releasing not only
greenhouse gases, but also formerly frozen
pollution.[91]
The West Antarctic ice sheet is likely to melt completely,[92][93][94] unless temperatures are reduced by 2 °C (3.6 °F) below the levels of the year 2020.[95] The loss of this ice sheet would take between 2,000 and 13,000 years,[96][97] although several centuries of high emissions could shorten this timeframe to 500 years.[98] A sea-level rise of 3.3 m (10 ft 10 in) would occur if the ice sheet collapses leaving ice caps on the mountains and 4.3 m (14 ft 1 in) if those ice caps also melt.[99]Isostatic rebound may contribute an additional 1 m (3 ft 3 in) to global sea levels over another 1,000 years.[98] In contrast, the East Antarctic ice sheet is far more stable and may only cause a sea-level rise of 0.5 m (1 ft 8 in) - 0.9 m (2 ft 11 in) from the current level of warming, a small fraction of the 53.3 m (175 ft) contained in the full ice sheet.[100] With a global warming of around 3 °C (5.4 °F), vulnerable areas like the
Wilkes Basin and
Aurora Basin may collapse over a period of around 2,000 years,[96][97] potentially adding up to 6.4 m (21 ft 0 in) to sea levels.[98] The complete melting and disappearance of the East Antarctic ice sheet would require at least 10,000 years, and it would only occur if global warming reaches 5 °C (9.0 °F) to 10 °C (18 °F).[96][97]
Scientists have studied the
ozone layer in the
atmosphere above Antarctica since the 1970s. In 1985, British scientists, working on data they had gathered at
Halley Research Station on the
Brunt Ice Shelf, discovered a large area of low
ozone concentration over Antarctica.[101][102] The 'ozone hole' covers almost the whole continent and was at its largest in September 2006;[103] the longest-lasting event occurred in 2020.[104] The depletion is caused by the
emission of
chlorofluorocarbons and halons into the atmosphere, which causes ozone to break down into other gases.[105] The extreme cold conditions of Antarctica allow
polar stratospheric clouds to form. The clouds act as
catalysts for chemical reactions, which eventually lead to the destruction of ozone.[106] The 1987
Montreal Protocol has restricted the emissions of ozone-depleting substances. The ozone hole above Antarctica is predicted to slowly disappear; by the 2060s, levels of ozone are expected to have returned to values last recorded in the 1980s.[107]
The ozone depletion can cause a cooling of around 6 °C (11 °F) in the
stratosphere. The cooling strengthens the
polar vortex and so prevents the outflow of the cold air near the South Pole, which in turn cools the continental mass of the East Antarctic ice sheet. The peripheral areas of Antarctica, especially the Antarctic Peninsula, are then subjected to higher temperatures, which accelerate the melting of the ice.[102] Models suggest that ozone depletion and the enhanced polar vortex effect may also account for the period of increasing sea ice extent, lasting from when observation started in the late 1970s until 2014. Since then, the coverage of Antarctic sea ice has decreased rapidly.[108][109]
Most species in Antarctica seem to be the descendants of species that lived there millions of years ago. As such, they must have survived multiple
glacial cycles. The species survived the periods of extremely cold climate in
isolated warmer areas, such as those with
geothermal heat or areas that remained ice-free throughout the colder climate.[110]
There are approximately 40 bird species that breed on or close to Antarctica, including species of
petrels,
penguins,
cormorants, and
gulls. Various other bird species visit the ocean around Antarctica, including some that normally reside in the Arctic.[117] The
emperor penguin is the only penguin that breeds during the winter in Antarctica; it and the
Adélie penguin breed farther south than any other penguin.[114]
A
Census of Marine Life by some 500 researchers during the
International Polar Year was released in 2010. The research found that more than 235 marine organisms live in both polar regions, having bridged the gap of 12,000 km (7,456 mi). Large animals such as some
cetaceans and birds make the round trip annually. Smaller forms of life, such as
sea cucumbers and
free-swimming snails, are also found in both polar oceans. Factors that may aid in their distribution include temperature differences between the deep ocean at the poles and the equator of no more than 5 °C (9 °F) and the major current systems or marine conveyor belts which are able to transport eggs and
larva.[118]
Fungi
About 1,150 species of
fungi have been recorded in the Antarctic region, of which about 750 are non-
lichen-forming.[119][120] Some of the species, having evolved under extreme conditions, have
colonised structural cavities within porous rocks and have contributed to shaping the rock formations of the McMurdo Dry Valleys and surrounding mountain ridges.[121]
The same features can be observed in algae and
cyanobacteria, suggesting that they are
adaptations to the conditions prevailing in Antarctica. This has led to speculation that
life on Mars might have been similar to Antarctic fungi, such as Cryomyces antarcticus and Cryomyces minteri.[121] Some of the species of fungi, which are apparently endemic to Antarctica, live in bird dung, and have evolved so they can grow inside extremely cold dung, but can also pass through the intestines of warm-blooded animals.[123][124]
Throughout its history, Antarctica has seen a wide variety of plant life. In the
Cretaceous, it was dominated by a fern-
conifer ecosystem, which changed into a temperate
rainforest by the end of that period. During the colder
Neogene (17–2.5 Ma), a
tundra ecosystem replaced the rainforests. The climate of present-day Antarctica does not allow extensive vegetation to form.[125] A combination of freezing temperatures, poor
soil quality, and a lack of moisture and sunlight inhibit plant growth, causing low
species diversity and limited distribution. The
flora largely consists of
bryophytes (25 species of
liverworts and 100 species of
mosses). There are three species of
flowering plants, all of which are found in the Antarctic Peninsula: Deschampsia antarctica (Antarctic hair grass), Colobanthus quitensis (Antarctic pearlwort) and the non-native Poa annua (annual bluegrass).[126]
Other organisms
Of the 700 species of algae in Antarctica, around half are marine
phytoplankton. Multicoloured
snow algae are especially abundant in the coastal regions during the summer.[127] Even
sea ice can harbour unique ecological communities, as it expels all salt from the water when it freezes, which accumulates into pockets of
brine that also harbour dormant microorganisms. When the ice begins to melt, brine pockets expand and can combine to form brine channels, and the
algae inside the pockets can reawaken and thrive until the next freeze.[128][129] Bacteria have also been found as deep as 800 m (0.50 mi) under the ice.[130] It is thought to be likely that there exists a native bacterial community within the subterranean water body of
Lake Vostok.[131] The existence of life there is thought to strengthen the argument for the possibility of life on
Jupiter's moon
Europa, which may have water beneath its water-ice crust.[132] There exists a community of
extremophile bacteria in the highly
alkaline waters of
Lake Untersee.[133][134] The prevalence of highly resilient creatures in such inhospitable areas could further bolster the argument for
extraterrestrial life in cold,
methane-rich environments.[135]
Early world maps, like the
1513 Piri Reis map, feature the hypothetical continent Terra Australis. Much larger than and unrelated to Antarctica, Terra Australis was a landmass that
classical scholars presumed necessary to balance the known lands in the northern hemisphere.[144]
Captain James Cook's ships,
HMS Resolution and
Adventure, crossed the Antarctic Circle on 17 January 1773, in December 1773, and again in January 1774.[145] Cook came within about 120 km (75 mi) of the Antarctic coast before retreating in the face of
field ice in January 1773.[146] In 1775, he called the existence of a polar continent "probable", and in another copy of his
journal he wrote: "[I] firmly believe it and it's more than probable that we have seen a part of it".[147]
19th century
Sealers were among the earliest to go closer to the Antarctic landmass, perhaps in the earlier part of the 19th century. The oldest known human remains in the Antarctic region was a skull, dated from 1819 to 1825, that belonged to a young woman on
Yamana Beach at the
South Shetland Islands. The woman, who was likely to have been part of a
sealing expedition, was found in 1985.[148]
The first person to see Antarctica or its ice shelf was long thought to have been the British sailor
Edward Bransfield, a captain in the
Royal Navy, who discovered the tip of the Antarctic peninsula on 30 January 1820. However, a captain in the
Imperial Russian Navy,
Fabian Gottlieb von Bellingshausen, recorded seeing an ice shelf on 27 January.[149] The American sealer
Nathaniel Palmer, whose sealing ship was in the region at this time, may also have been the first to sight the Antarctic Peninsula.[150]
On 22 January 1840, two days after the discovery of the coast west of the
Balleny Islands, some members of the crew of the 1837–1840 expedition of the French explorer
Jules Dumont d'Urville disembarked on the
Dumoulin Islands, off the coast of Adélie Land, where they took some mineral, algae, and animal samples, erected the French flag, and claimed French
sovereignty over the territory.[155] The American captain
Charles Wilkes led an expedition in 1838–1839 and was the first to claim he had discovered the continent.[156] The British naval officer
James Clark Ross failed to realise that what he referred to as "the various patches of land recently discovered by the American, French and English navigators on the verge of the Antarctic Circle" were connected to form a single continent.[157][158][159][note 5] The American explorer
Mercator Cooper landed on East Antarctica on 26 January 1853.[162]
The first confirmed landing on the continental mass of Antarctica occurred in 1895 when the Norwegian-Swedish
whaling ship
Antarctic reached
Cape Adare.[163]
20th century
During the Nimrod Expedition led by the British explorer
Ernest Shackleton in 1907, parties led by
Edgeworth David became the first to climb
Mount Erebus and to reach the
south magnetic pole.
Douglas Mawson, who assumed the leadership of the Magnetic Pole party on their perilous return, retired in 1931.[164] Between December 1908 and February 1909: Shackleton and three members of his expedition became the first humans to traverse the
Ross Ice Shelf, the first to cross the Transantarctic Mountains (via the Beardmore Glacier), and the first to set foot on the
south Polar Plateau. On 14 December 1911,
an expedition led by Norwegian explorer
Roald Amundsen from the ship Fram became the first to reach the geographic South Pole, using a route from the
Bay of Whales and up the
Axel Heiberg Glacier.[165] One month later, the doomed
Terra Nova Expedition reached the pole.[166]
The American explorer
Richard E. Byrd led four expeditions to Antarctica during the 1920s, 1930s, and 1940s, using the first mechanised
tractors. His expeditions conducted extensive geographical and scientific research, and he is credited with surveying a larger region of the continent than any other explorer.[167] In 1937,
Ingrid Christensen became the first woman to step onto the Antarctic mainland.[168]Caroline Mikkelsen had landed on an island of Antarctica, earlier in 1935.[169]
The South Pole was next reached on 31 October 1956, when a U.S. Navy group led by Rear Admiral
George J. Dufek successfully landed an aircraft there.[170] Six women were flown to the South Pole as a publicity stunt in 1969.[171][note 6] In the summer of 1996–1997, Norwegian explorer
Børge Ousland became the first person to cross Antarctica alone from coast to coast, helped by a kite on parts of the journey.[172] Ousland holds the record for the fastest unsupported journey to the South Pole, taking 34 days.[173]
The first semi-permanent inhabitants of regions near Antarctica (areas situated south of the
Antarctic Convergence) were British and American sealers who used to spend a year or more on
South Georgia, from 1786 onward. During the whaling era, which lasted until 1966, the population of the island varied from over 1,000 in the summer (over 2,000 in some years) to some 200 in the winter. Most of the whalers were Norwegian, with an increasing proportion from Britain.[174][note 7]
Antarctica's population consists mostly of the staff of
research stations in Antarctica (which are continuously maintained despite the population decline in the winter), although there are 2 all-civilian bases in Antarctica: the
Esperanza Base and the
Villa Las Estrellas base.[175] The number of people conducting and supporting scientific research and other work on the continent and its nearby islands varies from about 1,200 in winter to about 4,800 in the summer, with an additional 136 people in the winter to 266 people in the summer from the 2 civilian bases (as of 2017). Some of the
research stations are staffed year-round, the winter-over personnel typically arriving from their home countries for a one-year assignment. The
Russian OrthodoxHoly Trinity Church at the
Bellingshausen Station on
King George Island opened in 2004; it is manned year-round by one or two
priests, who are similarly rotated every year.[176][177]
Antarctica's status is regulated by the 1959
Antarctic Treaty and other related agreements, collectively called the Antarctic Treaty System. Antarctica is defined as all land and ice shelves south of 60° S for the purposes of the Treaty System.[1] The treaty was signed by twelve countries, including the
Soviet Union, the United Kingdom, Argentina,
Chile, Australia, and the United States. Since 1959, a further 42 countries have
acceded to the treaty. Countries can participate in decision-making if they can demonstrate that they do significant research on Antarctica; as of 2022[update], 29 countries have this 'consultative status'.[182] Decisions are based on
consensus, instead of a
vote. The treaty set aside Antarctica as a scientific preserve and established freedom of scientific investigation and environmental protection.[183][184]
In the present, sovereignty over regions of Antarctica is claimed by seven countries.[1] While a few of these countries have mutually recognised each other's claims,[190] the validity of the claims is not recognised universally.[1] New claims on Antarctica have been suspended since 1959, although in 2015, Norway formally defined Queen Maud Land as including the unclaimed area between it and the South Pole.[191]
The Argentine, British, and Chilean claims overlap and have caused friction. In 2012, after the British
Foreign & Commonwealth Office designated a previously unnamed area
Queen Elizabeth Land in tribute to
Queen Elizabeth II's
Diamond Jubilee,[192] the Argentine government protested against the claim.[193] The UK passed some of the areas it claimed to Australia and New Zealand after they achieved independence. The claims by Britain, Australia, New Zealand, France, and Norway do not overlap and are recognised by each other.[190] Other member nations of the Antarctic Treaty do not recognise any claim, yet have shown some form of territorial interest in the past.[194]
Deposits of coal,
hydrocarbons, iron ore,
platinum,
copper,
chromium,
nickel,
gold, and other minerals have been found in Antarctica, but not in large enough quantities to extract.[197] The Protocol on Environmental Protection to the Antarctic Treaty, which came into effect in 1998 and is due to be reviewed in 2048, restricts the exploitation of Antarctic resources, including minerals.[198]
Tourists have been
visiting Antarctica since 1957.[199] Tourism is subject to the provisions of the Antarctic Treaty and Environmental Protocol;[200] the self-regulatory body for the industry is the
International Association of Antarctica Tour Operators.[201] Tourists arrive by small or medium ship at specific scenic locations with accessible concentrations of iconic wildlife.[199] Over 74,000 tourists visited the region during the 2019–2020 season, of which 18,500 travelled on cruise ships but did not leave them to explore on land.[202] The numbers of tourists fell rapidly after the start of the
COVID-19 pandemic. Some nature conservation groups have expressed concern over the potential adverse effects caused by the influx of visitors and have called for limits on the size of visiting
cruise ships and a tourism quota.[203] The primary response by Antarctic Treaty parties has been to develop guidelines that set landing limits and closed or restricted zones on the more frequently visited sites.[204]
Overland sightseeing flights operated out of Australia and New Zealand until the
Mount Erebus disaster in 1979, when an
Air New Zealand plane crashed into Mount Erebus, killing all of the 257 people on board.
Qantas resumed commercial overflights to Antarctica from Australia in the mid-1990s.[205] There are many
airports in Antarctica.
Research
In 2017, there were more than 4,400 scientists undertaking research in Antarctica, a number that fell to just over 1,100 in the winter.[1] There are over 70 permanent and seasonal research stations on the continent; the largest, United States'
McMurdo Station, is capable of housing more than 1,000 people.[206][207] The
British Antarctic Survey has five major research stations on Antarctica, one of which is completely portable. The Belgian
Princess Elisabeth station is one of the most modern stations and the first to be
carbon-neutral.[208] Argentina, Australia, Chile, and Russia also have a large scientific presence on Antarctica.[1]
Geologists primarily study
plate tectonics,
meteorites, and the breakup of Gondwana.
Glaciologists study the history and dynamics of floating ice,
seasonal snow, glaciers, and ice sheets.
Biologists, in addition to researching wildlife, are interested in how low temperatures and the presence of humans affect adaptation and survival strategies in organisms.[209]Biomedical scientists have made discoveries concerning the spreading of
viruses and the body's response to extreme seasonal temperatures.[210]
The high elevation of the interior, the low temperatures, and the length of polar nights during the winter months all allow for better
astronomical observations at Antarctica than anywhere else on Earth.
The largest
neutrino detector in the world, the
IceCube Neutrino Observatory, is at the Amundsen-Scott Station. It consists of around 5,500
digital optical modules, some of which reach a depth of 2,450 m (8,040 ft), that are held in 1 km3 (0.24 cu mi) of ice.[213] Scientists also observed higher radiation dose rates around the coast of Antarctica compared with the global average: this is attributed to cosmic rays going through the thinner atmosphere compared to equatorial latitudes.[214]
Antarctica provides a unique environment for the study of meteorites: the dry polar desert preserves them well, and meteorites older than a million years have been found. They are relatively easy to find, as the dark stone meteorites stand out in a landscape of ice and snow, and the flow of ice accumulates them in certain areas.
The
Adelie Land meteorite, discovered in 1912, was the first to be found. Meteorites contain clues about the composition of the
Solar System and its early development.[215] Most meteorites come from asteroids, but a few meteorites found in Antarctica came from the Moon and Mars.[216][note 8]
Major scientific organizations in Antarctica have released strategy and action plans focused on advancing national interests and objectives in Antarctica, supporting cutting-edge research to understand the interactions between the Antarctic region and climate systems. The
British Antarctic Survey (BAS) released a 10-year (2023–2033) strategy report to reduce greenhouse gas emissions and to focus on creating sustainable living on
Earth.[218] Environmental sustainability is named as one of the top focus areas by the BAS strategy, highlighting the main challenge and priority to embed environmental sustainability into everything.[219]
In 2022, the
Australian Antarctic Program (AAP) released a new Strategy and 20-year Action Plan (2022–2036) to modernize its Antarctic program. The global climate system was highlighted as one of the main priorities that will be supported and studied through the AAP Strategy Plan. It emphasizes the importance of understanding the vital role of Antarctica and the Southern Ocean in climate and weather to improve current knowledge and inform management responses.[220]
In 2021, the
United States Antarctic Program (USAP) released a Midterm Assessment on the 2015 Strategic Vision for Antarctic and Southern Ocean Research, stressing the prominent role of the Southern Ocean in the global carbon cycle and sea level rise.[221] The USAP outlines the Changing Antarctic Ice Sheets Initiative as a top priority to enhance understanding of why ice sheets are changing now, and how they will change in the future.[222]
Antarctic ice sheets are a central focus of contemporary climate research due to urgent questions about their stability and reaction to global warming.
Satellite technology enables researchers to study the ice sheets both through on-site fieldwork and
remote sensing, facilitating detailed analyses of ice dynamics to predict future changes in a warming world.
The INStabilities & Thresholds in ANTarctica (INSTANT) Scientific Research Programme proposes three research themes, investigating the complex interactions between the
atmosphere,
ocean, and solid
Earth in Antarctica. Its aims include improving the understanding and predictions of these processes to aid decision makers in risk assessment, management, and mitigation related to Antarctic climate change.
The Australian-led ICECAP project utilized advanced aerogeophysical techniques to map deep subglacial basins and
channels that connect the ice sheet to the ocean.[223] This mapping improves predictions of ice sheet stability, the impacts of
climate change on the ice sheets, and their potential contributions to global
sea level rise.[223]
^The word was originally pronounced with the first c silent in English, but the
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Medieval Latin and was dropped from the spelling in
Old French, but it was added back for etymological reasons in English in the 17th century and thereafter began to be pronounced, but (as with other spelling pronunciations) at first only by less educated people.[3] For those who pronounce the first t, there is also variation between the pronunciations Ant-ar(c)tica and An-tar(c)tica.
^Ross passed through what is now known as the Ross Sea and discovered Ross Island (both of which were named after him) in 1841. He sailed along a huge wall of ice that was later named the
Ross Ice Shelf.[160]Mount Erebus and
Mount Terror are named after two ships from his expedition:
HMS Erebus and
Terror.[161]
^Antarctician meteorites, particularly
ALH84001 discovered by
ANSMET, were at the centre of the controversy about possible evidence of
life on Mars. Because meteorites in space absorb and record cosmic radiation, the time elapsed since the meteorite hit the Earth can be calculated.[217]
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