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56-705: Finn Ronne (December 20, 1899 – January 12, 1980) was a Norwegian-born U.S. citizen and Antarctic explorer. Finn Ronne was born in Horten , in Vestfold county, Norway . His father, Martin Rønne (1861–1932), was a polar explorer who served in Roald Amundsen 's successful expedition to the South Pole . Ronne received his education in engineering at Horten Technical College. In 1923 Finn Ronne immigrated to

112-415: A "hotspot of global warming". It broke over a period of three weeks or less, with a factor in this fast break-up being the powerful effects of water; ponds of meltwater formed on the surface during the near 24 hours of daylight in the summertime, flowed down into cracks and, acting like a multitude of wedges, levered the shelf apart. Other likely factors in the break-up were the higher ocean temperatures and

168-522: A huge ice island in 2017. From 31 January 2002 to March 2002 the Larsen B sector partially collapsed and parts broke up, 3,250 km (1,250 sq mi) of ice 220 m (720 ft) thick, an area comparable to the US state of Rhode Island . In 2015, a study concluded that the remaining Larsen B ice-shelf would disintegrate by 2020, based on observations of faster flow and rapid thinning of glaciers in

224-615: A large crack in the Ward Hunt shelf had begun to form, and in 2003 it was announced that the ice sheet had split completely in two in 2002, releasing a huge pool of freshwater from the largest epishelf lake in the Northern Hemisphere, located in Disraeli Fjord. In April 2008, scientists discovered that the shelf fractured into dozens of deep, multi-faceted cracks. On August 13, 2005, The Ayles Ice Shelf , which

280-558: A slow melt rate, in contrast to the undefended western portion. According to the American Geophysical Union in a 2021 study, the Thwaites Eastern Ice Shelf (TEIS) buttresses one-third of Thwaites glacier . Removal of the shelf has the potential to increase the contribution of Thwaites glacier to sea level rise by up to 25%. As of 2021 , the ice shelf appears to be losing its grip on

336-459: A submarine shoal that acts as a pinning point and the shear margin that separates the Thwaites Eastern Ice Shelf from the Thwaites glacier Tongue has extended, further weakening the ice shelf connection to the pinning point. A sequence of Sentinel-1 radar imagery shows that parallel wing and comb cracks have recently formed rifts at high angles to the main shear margin and are propagating into

392-799: Is a polar region around Earth 's South Pole , opposite the Arctic region around the North Pole . The Antarctic comprises the continent of Antarctica , the Kerguelen Plateau , and other island territories located on the Antarctic Plate or south of the Antarctic Convergence . The Antarctic region includes the ice shelves , waters, and all the island territories in the Southern Ocean situated south of

448-521: Is about 1028 kg/m and that of glacial ice from about 850 kg/m to well below 920 kg/m , the limit for very cold ice without bubbles. The height of the shelf above the sea can be even larger, if there is much less dense firn and snow above the glacier ice. A large portion of the Antarctic coastline has ice shelves attached. Their aggregate area is over 1,550,000 square kilometers (600,000 square miles). It has been found that of all

504-542: Is commonly accepted to have occurred in 1820 by the Russian expedition of Fabian Gottlieb von Bellingshausen and Mikhail Lazarev on Vostok and Mirny . The Australian James Kerguelen Robinson (1859–1914) was the first human born in the Antarctic, on board the sealing ship Offley in the Gulf of Morbihan (Royal Sound then), Kerguelen Island on 11 March 1859. The first human born and raised on an Antarctic island

560-546: Is credited to the Spaniard Gabriel de Castilla , who reported seeing distant southern snow-capped mountains in 1603. The first Antarctic land discovered was the island of South Georgia , visited by the English merchant Anthony de la Roché in 1675. Although such myths and speculation about a Terra Australis ("Southern Land") date back to antiquity, the first confirmed sighting of the continent of Antarctica

616-428: Is low on the islands: studies have theorized that the harsh climate was a major contributor towards species richness, but multiple correlations have been found with area, temperature, remoteness of islands, and food chain stability. For example, herbivorous insects are poor in number due to low plant richness, and likewise, indigenous bird numbers are related to insects, which are a major food source. The Antarctic hosts

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672-491: Is managed through an international commission headquartered in Hobart , Australia, by an efficient system of annual fishing quotas, licenses, and international inspectors on the fishing vessels, as well as satellite surveillance. The islands situated between 60°S latitude parallel to the south and the Antarctic Convergence to the north and their respective 200-nautical-mile (370 km) exclusive economic zones fall under

728-763: Is no permanent country in Antarctica . As defined by the Antarctic Treaty System , the Antarctic region is everything south of the 60°S latitude . The Treaty area covers Antarctica and the archipelagos of the Balleny Islands , Peter I Island , Scott Island , the South Orkney Islands , and the South Shetland Islands . However, this area does not include the Antarctic Convergence , a transition zone where

784-627: Is one of the biggest ice shelves in West Antarctica , though it is highly unstable and disintegrating rapidly. Since the 1980s, the Thwaites Glacier , nicknamed the "Doomsday glacier", has had a net loss of over 600 billion tons of ice, though pinning of the Thwaites Ice Shelf has served to slow the process. The Thwaites Ice Shelf has acted like a dam for the eastern portion of glacier, bracing it and allowing for

840-722: Is set to expire in 35 years. ) To protect the area, all Antarctic ships over 500 tonnes are subject to mandatory regulations under the Polar Code , adopted by the International Maritime Organization (in force since 1 January 2017). 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, climate change in Antarctica has been observed. Since 1959, there has been an average temperature increase of >0.05 °C/decade since 1957 across

896-496: The Antarctic Convergence , a zone approximately 32 to 48 km (20 to 30 mi) wide and varying in latitude seasonally. The region covers some 20 percent of the Southern Hemisphere , of which 5.5 percent (14 million km ) is the surface area of the Antarctica continent itself. All of the land and ice shelves south of 60°S latitude are administered under the Antarctic Treaty System . Biogeographically ,

952-496: The Antarctic realm is one of eight biogeographic realms on Earth's land surface. Climate change in Antarctica is particularly important because the melting of the Antarctic ice sheet has a high potential to add to the global sea level rise . Further, this melting also disrupts the flow of Southern Ocean overturning circulation , which would have significant effects on the local climate and marine ecosystem functioning.There

1008-622: The Arctic ( Greenland , Northern Canada , and the Russian Arctic ), and can range in thickness from about 100–1,000 m (330–3,280 ft). The world's largest ice shelves are the Ross Ice Shelf and the Filchner-Ronne Ice Shelf in Antarctica. The movement of ice shelves is principally driven by gravity -induced pressure from the grounded ice. That flow continually moves ice from the grounding line to

1064-607: The Karpinsky Ice Cap to the south and the Rusanov Ice Cap to the north. In 2012 it ceased to exist. In the last several decades, glaciologists have observed consistent decreases in ice shelf extent through melt, calving , and complete disintegration of some shelves. Well studied examples include disruptions of the Thwaites Ice Shelf , Larsen Ice Shelf , Filchner–Ronne Ice Shelf (all three in

1120-661: The Markham Ice Shelf broke up in 2008. The remaining ice shelves have also lost a significant amount of their area over time, with the Milne Ice Shelf being the last to be affected, with it breaking off in August 2020. The Matusevich Ice Shelf was a 222 square kilometers (86 square miles) ice shelf located in Severnaya Zemlya being fed by some of the largest ice caps on October Revolution Island ,

1176-714: The North American Newspaper Alliance ". She and the chief pilot's wife Jennie Darlington were the first women to overwinter in Antarctica. In the 1950s, the Navy organized Operation Deepfreeze to complete the mapping of Antarctica and establish centers for scientific research. Ronne became the scientific and military leader for a U.S. Weddell Sea base . During his lifetime he wrote several books on Antarctica and many scientific papers on Antarctic research. He received three medals and numerous military awards for service, for geographical exploration and for

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1232-593: The Thwaites Ice Shelf , Larsen Ice Shelf , Filchner–Ronne Ice Shelf (all three in the Antarctic) and the disruption of the Ellesmere Ice Shelf in the Arctic. An ice shelf is "a floating slab of ice originating from land of considerable thickness extending from the coast (usually of great horizontal extent with a very gently sloping surface), resulting from the flow of ice sheets , initially formed by

1288-657: The 1940s, with support of the American Geographical Society as the leader of the Ronne Antarctic Research Expedition . From 1946 to 1948 his team mapped and explored the Weddell Sea coastline and set a number of polar records. Ronne covered 3,600 miles by ski and dog sled —more than any other explorer in history. His wife Edith Ronne accompanied him on this expedition, serving as "historian and correspondent for

1344-494: The Antarctic) and the disruption of the Ellesmere Ice Shelf in the Arctic. The effects of climate change are visible in the changes to the cryosphere , such as reduction in sea ice and ice sheets , and disruption of ice shelves. Thwaites Ice Shelf (), is an Antarctic ice shelf in the Amundsen Sea . It was named by ACAN after Fredrik T. Thwaites, a glacial geologist and geomorphologist . The Thwaites Ice Shelf

1400-540: The Convergence and thus outside the Antarctic region. A variety of animals live in Antarctica for at least some of the year, including: Most of the Antarctica continent is permanently covered by ice and snow, leaving less than 1 percent of the land exposed. There are only two species of flowering plant, Antarctic hair grass and Antarctic pearlwort , but a range of mosses , liverworts , lichens and macrofungi . Biodiversity among terrestrial flora and fauna

1456-554: The Ellesmere Ice Shelf had been in place for at least 3,000 years. During the twentieth century, the Ellesmere Ice Shelf broke up into six separate shelves. From west to east, these were the Serson Ice Shelf , Petersen Ice Shelf , Milne Ice Shelf , Ayles Ice Shelf , Ward Hunt Ice Shelf , and Markham Ice Shelf . The smaller pieces continued to disintegrate. In April 2000, satellite images revealed that

1512-585: The Milne Ice Shelf, also ultimately experienced a major breakup at the end of July 2020, losing over 40% of its area. The Ellesmere Ice Shelf was the largest ice shelf in the Arctic, encompassing about 9,100 square kilometres (3,500 square miles) of the north coast of Ellesmere Island , Nunavut , Canada. The ice shelf was first documented by the British Arctic Expedition of 1875–76, in which Lieutenant Pelham Aldrich 's party went from Cape Sheridan to Cape Alert . The continuous mass of

1568-583: The November 2006 sighting of several large icebergs from the coast of the South Island of New Zealand , the first time since 1931 that any icebergs had been observed from the New Zealand mainland. A large group of small icebergs (the largest some 1000 metres in length), were seen off the south-east coast of the island, with one of them drifting close enough to shore to be visible from the hills above

1624-537: The U.S. and gained citizenship in 1929. After working at Westinghouse Electric Corporation for some years, he took part in two of Richard E. Byrd 's expeditions to the South Pole, and in 1939 Ronne served as Byrd's executive officer helping discover one thousand miles of new coastline. After serving several years in the United States Navy , gaining the rank of captain, Ronne returned to Antarctica in

1680-562: The West Antarctic, the ocean has warmed by 1 °C (1.8 °F) since 1955. The fresh, 1100-1500 billion tons (GT) per year of meltwater from the ice dilutes the saline Antarctic bottom water , weakening the lower cell of the Southern Ocean overturning circulation (SOOC). According to some research, a full collapse of the SOOC may occur a between 1.7 °C (3.1 °F) and 3 °C (5.4 °F) of global warming, although

1736-615: The accumulation of snow, and often filling embayments in the coastline of an ice sheet." In contrast, sea ice is formed on water, is much thinner (typically less than 3 m (9.8 ft)), and forms throughout the Arctic Ocean . It is also found in the Southern Ocean around the continent of Antarctica . The term captured ice shelf has been used for the ice over a subglacial lake , such as Lake Vostok . Ice shelves are thick plates of ice, formed continuously by glaciers, that float atop an ocean. The shelves act as "brakes" for

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1792-857: The advancement of science. He was awarded the St. Olav's Medal by the King of Norway . At his death in 1980, in Bethesda, Maryland , he was buried at Arlington National Cemetery , Arlington, Virginia . The Finn Ronne Memorial Award is awarded by the Explorers Club to an individual noted for accomplishments in polar field research that best typify the spirit of Finn Ronne. Antarctic The Antarctic ( / æ n ˈ t ɑːr t ɪ k / or / æ n ˈ t ɑːr k t ɪ k / , American English also / æ n t ˈ ɑːr t ɪ k / or / æ n t ˈ ɑːr k t ɪ k / ; commonly / æ ˈ n ɑːr t ɪ k / )

1848-400: The area. Larsen B was stable for at least 10,000 years, essentially the entire Holocene period since the last glacial period. By contrast, Larsen A was absent for a significant part of that period, reforming about 4,000 years ago. Despite its great age, the Larsen B was clearly in trouble at the time of the collapse. With warm currents eating away the underside of the shelf, it had become

1904-453: The central part of the ice shelf at rates as high as 2 km per year. Satellite data, ground-penetrating radar, and GPS measurements taken in 2021 indicate that collapse of the ice shelf may be initiated by intersection of rifts with hidden basal crevasse zones as soon as 2026. Two sections of Antarctica's Larsen Ice Shelf broke apart into hundreds of unusually small fragments (hundreds of meters wide or less) in 1995 and 2002, Larsen C calved

1960-714: The city of Dunedin . If these were indeed the remnants of this calving, then over the course of five and a half years they had travelled slowly north and also east around over half the globe, a journey of some 13,500 km. From January 12 and January 13, 2010, an area of sea ice larger than the state of Rhode Island , or one-seventh the size of Wales , broke away from the Ronne–Filchner Ice Shelf and shattered into many smaller pieces. The Moderate-Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua and Terra satellites captured this event in this series of photo-like images. In May 2021, Iceberg A-76 broke off

2016-523: The cold waters of the Southern Ocean collide with the warmer waters of the north, forming a natural border to the region. Because the Convergence changes seasonally, the Convention for the Conservation of Antarctic Marine Living Resources approximates the Convergence line by joining specified points along parallels of latitude and meridians of longitude . The implementation of the convention

2072-724: The conference were presented at the Antarctic Treaty states' meeting in Uruguay in May 2010. Because Antarctica surrounds the South Pole , it is theoretically located in all time zones . For practical purposes, time zones are usually based on territorial claims or the time zone of a station's owner country or supply base. 90°00′S 00°00′W  /  90.000°S -0.000°E  / -90.000; -0.000 Ice shelf Ice shelves are found in Antarctica and

2128-496: The continent, although it had been uneven. 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. The colder, stabler East Antarctica had been experiencing cooling until the 2000s. Around Antarctica, the Southern Ocean has absorbed more oceanic heat than any other ocean, and has seen strong warming at depths below 2,000 m (6,600 ft). Around

2184-466: The decline of the ice of the peninsula. In October 1998, the iceberg A-38 broke off the Filchner–Ronne ice shelf. It had an extent of roughly 150 by 50 km and was thus larger than Delaware . It later broke up again into three parts. A similar-sized calving in May 2000 created an iceberg 167 by 32 km in extent, dubbed A-43 – the disintegration of this is thought to have been responsible for

2240-509: The floating ice is above the ocean surface, depending on how much pressurized air is contained in the bubbles within the glacial ice, stemming from compressed snow. The formula for the denominators above is 1 / [ ( ρ seawater − ρ glacial ice ) / ρ seawater ] {\textstyle 1/[(\rho _{\text{seawater}}-\rho _{\text{glacial ice}})/\rho _{\text{seawater}}]} , density of cold seawater

2296-752: The full effects are expected to occur over multiple centuries; these include less precipitation in the Southern Hemisphere but more in the Northern Hemisphere , an eventual decline of fisheries in the Southern Ocean and a potential collapse of certain marine ecosystems . While many Antarctic species remain undiscovered, there are documented increases in Antarctic flora , and large fauna such as penguins are already having difficulty retaining suitable habitat. On ice-free land, permafrost thaws release greenhouse gases and formerly frozen pollution. The first recorded sighting of Antarctica

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2352-652: The glaciers. These shelves serve another important purpose—"they moderate the amount of melting that occurs on the glaciers' surfaces. Once their ice shelves are removed, the glaciers increase in speed due to meltwater percolation and/or a reduction of braking forces, and they may begin to dump more ice into the ocean than they gather as snow in their catchments. Glacier ice speed increases are already observed in Peninsula areas where ice shelves disintegrated in prior years." The density contrast between glacial ice and liquid water means that at least ⁠ 1 / 9 ⁠ of

2408-477: The ice shelf. The Ellesmere ice shelf was reduced by 90% in the twentieth century, leaving the separate Alfred Ernest , Ayles , Milne , Ward Hunt , and Markham ice shelves. A 1986 survey of Canadian ice shelves found that 48 km (3.3 cubic kilometres) of ice calved from the Milne and Ayles ice shelves between 1959 and 1974. The Ayles Ice Shelf calved entirely on August 13, 2005. The Ward Hunt Ice Shelf,

2464-422: The ice shelves on Earth, nearly all of them are in Antarctica. In steady state, about half of Antarctica's ice shelf mass is lost to basal melt and half is lost to calving , but the relative importance of each process varies significantly between ice shelves. In recent decades, Antarctica's ice shelves have been out of balance, as they have lost more mass to basal melt and calving than has been replenished by

2520-448: The influx of new ice and snow. The Ross Ice Shelf is the largest ice shelf of Antarctica (as of 2013 , an area of roughly 500,809 square kilometres (193,363 sq mi) and about 800 kilometres (500 mi) across: about the size of France). It is several hundred metres thick. The nearly vertical ice front to the open sea is more than 600 kilometres (370 mi) long, and between 15 and 50 metres (50 and 160 ft) high above

2576-557: The largest remaining section of thick (>10 meters (33 feet)) landfast sea ice along the northern coastline of Ellesmere Island, lost 600 square kilometers (230 square miles) of ice in a massive calving in 1961–1962. It further decreased by 27% in thickness (13 meters (43 feet)) between 1967 and 1999. In the summer of 2002, the Ward Ice Shelf experienced another major breakup, and other instances of note happened in 2008 and 2010 as well. The last remnant to remain mostly intact,

2632-547: The most popular destinations being the Antarctic Peninsula area (especially the South Shetland Islands ) and South Georgia Island . In December 2009, the growth of tourism , with consequences for both the ecology and the safety of the travellers in its great and remote wilderness, was noted at a conference in New Zealand by experts from signatories to the Antarctic Treaty . The definitive results of

2688-843: The national jurisdiction of the countries that possess them: South Georgia and the South Sandwich Islands (United Kingdom), Bouvet Island (Norway), and Heard and McDonald Islands (Australia). Kerguelen Islands (France; also an EU Overseas territory) are situated in the Antarctic Convergence area, while the Isla Grande de Tierra del Fuego , Falkland Islands , Isla de los Estados , Hornos Island with Cape Horn , Diego Ramírez Islands , Campbell Island , Macquarie Island , Amsterdam and Saint Paul Islands, Crozet Islands , Prince Edward Islands , Gough Island , and Tristan da Cunha group remain north of

2744-424: The northwest corner of the shelf. At 4320 km , it is larger than Majorca , several times larger than Iceberg A-74 which calved in the same year, or approximately 14% the size of Belgium . The ice of the Filchner–Ronne ice shelf can be as thick as 600 m; the water below is about 1400 m deep at the deepest point. The international Filchner–Ronne Ice Shelf Programme (FRISP) was initiated in 1973 to study

2800-425: The seaward front of the shelf. Typically, a shelf front will extend forward for years or decades between major calving events (calving is the sudden release and breaking away of a mass of ice from a glacier , iceberg , ice front , ice shelf, or crevasse ). Snow accumulation on the upper surface and melting from the lower surface are also important to the mass balance of an ice shelf. Ice may also accrete onto

2856-467: The southernmost. In late 1977, Silvia Morella de Palma, who was then seven months pregnant, was airlifted to Esperanza Base , in order to complete her pregnancy in the base. The airlift was a part of the Argentine solutions to the sovereignty dispute over territory in Antarctica. Emilio was automatically granted Argentine citizenship by the government since his parents were both Argentine citizens, and he

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2912-404: The underside of the shelf. The effects of climate change are visible in the changes to the cryosphere , such as reduction in sea ice and ice sheets , and disruption of ice shelves. In the last several decades, glaciologists have observed consistent decreases in ice shelf extent through melt, calving , and complete disintegration of some shelves. Well studied examples include disruptions of

2968-554: The water surface. Ninety percent of the floating ice, however, is below the water surface. All Canadian ice shelves are attached to Ellesmere Island and lie north of 82°N. Ice shelves that are still in existence are the Alfred Ernest Ice Shelf , Ward Hunt Ice Shelf , Milne Ice Shelf and Smith Ice Shelf . The M'Clintock Ice Shelf broke up from 1963 to 1966; the Ayles Ice Shelf broke up in 2005; and

3024-766: The world's largest protected area comprising 1.07 million km , the South Georgia and the South Sandwich Islands Marine Protection Area created in 2012. The latter exceeds the surface area of another vast protected territory, the Greenland National Park 's 972,000 km (375,000 sq mi). (While the Ross Sea Marine Protection Area established in 2016 is still larger at 1.55 million km , its protection

3080-661: Was Solveig Gunbjørg Jacobsen born on 8 October 1913 in Grytviken , South Georgia. Emilio Marcos Palma (born 7 January 1978) is an Argentine man who was the first documented person born on the continent of Antarctica at the Esperanza Base . His father, Captain Jorge Palma, was head of the Argentine Army detachment at the base. While ten people have been born in Antarctica since, Palma's birthplace remains

3136-449: Was born in the claimed Argentine Antarctica . Palma can be considered to be the first native Antarctican. The Antarctic region had no indigenous population when first discovered, and its present inhabitants comprise a few thousand transient scientific and other personnel working on tours of duty at the several dozen research stations maintained by various countries. However, the region is visited by more than 40,000 tourists annually,

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