Thwaites Ice Shelf

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Thwaites Ice Shelf A close look at the shelf (8093672443).jpg
Thwaites Ice Shelf

Thwaites Ice Shelf ( 75°6′S105°31′W / 75.100°S 105.517°W / -75.100; -105.517 ), is an Antarctic ice shelf in the Amundsen Sea. It was named by ACAN [1] after Fredrik T. Thwaites, a glacial geologist and geomorphologist. The Thwaites Ice Shelf is one of the biggest ice shelves in West Antarctica, though it is highly unstable and disintegrating rapidly. [2] [3] Since the 1980s, the Thwaites glacier, nicknamed the "Doomsday glacier", [4] 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. [5] The Thwaites Ice Shelf has acted like a dam for the eastern portion of glacier, bracing it and allowing for a slow melt rate, in contrast to the undefended western portion. [4] [6]

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%. [7] As of 2021, the ice shelf appears to be losing its grip on 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. [7]

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 the central part of the ice shelf at rates as high as 2 km per year. Satellite data, ground-penetrating radar, and GPS measurements indicate that collapse of the ice shelf may be initiated by intersection of rifts with hidden basal crevasse zones within as little as 5 years. [7]

Complete melting of Thwaites glacier is predicted to increase global sea levels by 65 cm (2.13 ft) according to the European Geosciences Union, [8] and the Cooperative Institute for Research in Environmental Sciences states that the collapse of Thwaites glacier could ultimately lead to sea-level rise of up to 3 meters [9] if it draws the Pine Island and surrounding glaciers with it, due to marine ice sheet instability. However, both of these processes would take time: a Science Magazine interview with the International Thwaites Glacier Collaboration researchers who had discovered the impending collapse of the ice shelf noted that the glacier itself would still take approximately several centuries to collapse even without the ice shelf, [10] and a 2022 assessment of tipping points in the climate system stated that while the West Antarctic Ice Sheet may be committed to disintegration at between 1°C and 3°C, the timescale for its collapse after that ranges between 500 and 13,000 years, with the most likely estimate of 2000 years. [11] [12]

See also

Related Research Articles

<span class="mw-page-title-main">Climate of Antarctica</span> Overview of climactic conditions in Antarctica

The climate of Antarctica is the coldest on Earth. The continent is also extremely dry, averaging 166 mm (6.5 in) of precipitation per year. Snow rarely melts on most parts of the continent, and, after being compressed, becomes the glacier ice that makes up the ice sheet. Weather fronts rarely penetrate far into the continent, because of the katabatic winds. Most of Antarctica has an ice-cap climate with extremely cold and dry weather.

<span class="mw-page-title-main">Ice shelf</span> Large floating platform of ice caused by glacier flowing onto ocean surface

An ice shelf is a large floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface. Ice shelves are only found in Antarctica, Greenland, Northern Canada, and the Russian Arctic. The boundary between the floating ice shelf and the anchor ice that feeds it is the grounding line. The thickness of ice shelves can range from about 100 m (330 ft) to 1,000 m (3,300 ft).

<span class="mw-page-title-main">Ice sheet</span> Large mass of glacial ice

In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than 50,000 km2 (19,000 sq mi). The only current ice sheets are in Antarctica and Greenland; during the Last Glacial Period at Last Glacial Maximum, the Laurentide Ice Sheet covered much of North America, the Weichselian ice sheet covered Northern Europe and the Patagonian Ice Sheet covered southern South America.

<span class="mw-page-title-main">Filchner–Ronne Ice Shelf</span> Ice shelf in Antarctica

<span class="mw-page-title-main">Amundsen Sea</span> Arm of the Southern Ocean

The Amundsen Sea is an arm of the Southern Ocean off Marie Byrd Land in western Antarctica. It lies between Cape Flying Fish to the east and Cape Dart on Siple Island to the west. Cape Flying Fish marks the boundary between the Amundsen Sea and the Bellingshausen Sea. West of Cape Dart there is no named marginal sea of the Southern Ocean between the Amundsen and Ross Seas. The Norwegian expedition of 1928–1929 under Captain Nils Larsen named the body of water for the Norwegian polar explorer Roald Amundsen while exploring this area in February 1929.

<span class="mw-page-title-main">West Antarctic Ice Sheet</span> Segment of the continental ice sheet that covers West (or Lesser) Antarctica

The Western Antarctic Ice Sheet (WAIS) is the segment of the continental ice sheet that covers West Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains that lies in the Western Hemisphere. The WAIS is classified as a marine-based ice sheet, meaning that its bed lies well below sea level and its edges flow into floating ice shelves. The WAIS is bounded by the Ross Ice Shelf, the Ronne Ice Shelf, and outlet glaciers that drain into the Amundsen Sea.

<span class="mw-page-title-main">Larsen Ice Shelf</span> Ice shelf in Antarctica

The Larsen Ice Shelf is a long ice shelf in the northwest part of the Weddell Sea, extending along the east coast of the Antarctic Peninsula from Cape Longing to Smith Peninsula. It is named after Captain Carl Anton Larsen, the master of the Norwegian whaling vessel Jason, who sailed along the ice front as far as 68°10' South during December 1893. In finer detail, the Larsen Ice Shelf is a series of shelves that occupy distinct embayments along the coast. From north to south, the segments are called Larsen A, Larsen B, and Larsen C by researchers who work in the area. Further south, Larsen D and the much smaller Larsen E, F and G are also named.

<span class="mw-page-title-main">Marie Byrd Land</span> Unclaimed West Antarctic region

Marie Byrd Land (MBL) is an unclaimed region of Antarctica. With an area of 1,610,000 km2 (620,000 sq mi), it is the largest unclaimed territory on Earth. It was named after the wife of American naval officer Richard E. Byrd, who explored the region in the early 20th century.

<span class="mw-page-title-main">Antarctic ice sheet</span> Earths southern polar ice cap

The Antarctic ice sheet is one of the two polar ice caps of Earth. It covers about 98% of the Antarctic continent and is the largest single mass of ice on Earth, with an average thickness of over 2 kilometers. Separate to the Antarctic sea ice it covers an area of almost 14 million square kilometres and contains 26.5 million cubic kilometres of ice. A cubic kilometer of ice weighs approximately 0.92 metric gigatonnes, meaning that the ice sheet weighs about 24,380,000 gigatonnes. It holds approximately 61% of all fresh water on Earth, equivalent to about 58 meters of sea level rise if all the ice were above sea level. In East Antarctica, the ice sheet rests on a major land mass, while in West Antarctica the bed can extend to more than 2,500 m below sea level.

<span class="mw-page-title-main">Pine Island Glacier</span> Large ice stream, fastest melting glacier in Antarctica

Pine Island Glacier (PIG) is a large ice stream, and the fastest melting glacier in Antarctica, responsible for about 25% of Antarctica's ice loss. The glacier ice streams flow west-northwest along the south side of the Hudson Mountains into Pine Island Bay, Amundsen Sea, Antarctica. It was mapped by the United States Geological Survey (USGS) from surveys and United States Navy (USN) air photos, 1960–66, and named by the Advisory Committee on Antarctic Names (US-ACAN) in association with Pine Island Bay.

<span class="mw-page-title-main">Thwaites Glacier</span> Antarctic glacier

Thwaites Glacier is an unusually broad and vast Antarctic glacier located east of Mount Murphy, on the Walgreen Coast of Marie Byrd Land. It was initially sighted by polar researchers in 1940, mapped in 1959–1966 and officially named in 1967, after the late American glaciologist Fredrik T. Thwaites. The glacier flows into Pine Island Bay, part of the Amundsen Sea, at surface speeds which exceed 2 kilometres (1.2 mi) per year near its grounding line. Its fastest-flowing grounded ice is centered between 50 and 100 kilometres east of Mount Murphy. Like many other parts of the cryosphere, it has been adversely affected by climate change, and provides one of the more notable examples of the retreat of glaciers since 1850.

<span class="mw-page-title-main">Retreat of glaciers since 1850</span> Shortening of glaciers by melting

The retreat of glaciers since 1850 is well documented and is one of the effects of climate change. The retreat of mountain glaciers, notably in western North America, Asia, the Alps and tropical and subtropical regions of South America, Africa and Indonesia, provide evidence for the rise in global temperatures since the late 19th century. The acceleration of the rate of retreat since 1995 of key outlet glaciers of the Greenland and West Antarctic ice sheets may foreshadow a rise in sea level, which would affect coastal regions. Excluding peripheral glaciers of ice sheets, the total cumulated global glacial losses over the 26 year period from 1993–2018 were likely 5500 gigatons, or 210 gigatons per yr.

<span class="mw-page-title-main">Nordenskjöld Coast</span> Coast in Antarctica

The Nordenskjöld Coast is located on the Antarctic Peninsula, more specifically Graham Land, which is the top region of the Peninsula. The Peninsula is a thin, long ice sheet with an Alpine-style mountain chain. The coast consists of 15m tall ice cliffs with ice shelves.

<span class="mw-page-title-main">Eric Rignot</span> American scientist

Eric J. Rignot is a chancellor professor of Earth system science at the University of California, Irvine, and senior research scientist for the Radar Science and Engineering Section at NASA's Jet Propulsion Laboratory.

<span class="mw-page-title-main">Ice calving</span> Breaking of ice chunks from the edge of a glacier

Ice calving, also known as glacier calving or iceberg calving, is the breaking of ice chunks from the edge of a glacier. It is a form of ice ablation or ice disruption. It is the sudden release and breaking away of a mass of ice from a glacier, iceberg, ice front, ice shelf, or crevasse. The ice that breaks away can be classified as an iceberg, but may also be a growler, bergy bit, or a crevasse wall breakaway.

<span class="mw-page-title-main">Rutford Ice Stream</span> Antarctic ice stream

Rutford Ice Stream is a major Antarctic ice stream, about 290 kilometres (180 mi) long and over 24 kilometres (15 mi) wide, which drains southeastward between the Sentinel Range, Ellsworth Mountains and Fletcher Ice Rise into the southwest part of Ronne Ice Shelf. Named by US-ACAN for geologist Robert Hoxie Rutford, a member of several USARP expeditions to Antarctica; leader of the University of Minnesota Ellsworth Mountains Party, 1963-1964. Rutford served as Director of the Division of Polar Programs, National Science Foundation, 1975-1977.

<span class="mw-page-title-main">Crane Glacier</span> Glacier in the Aristotle Mountains of the Antarctic Peninsula

Crane Glacier, is a narrow glacier which flows 30 miles (50 km) in an east-northeasterly direction along the northwest side of Aristotle Mountains to enter Spillane Fjord south of Devetaki Peak, on the east coast of the Antarctic Peninsula. Sir Hubert Wilkins photographed this feature from the air in 1928 and gave it the name "Crane Channel", after C.K. Crane of Los Angeles, reporting that it appeared to be a channel cutting in an east-west direction across the peninsula. The name was altered to "Crane Inlet" following explorations along the west coast of the peninsula in 1936 by the British Graham Land Expedition, which proved that no through channel from the east coast existed as indicated by Wilkins. Comparison of Wilkins' photograph of this feature with those taken in 1947 by the Falklands Islands Dependencies Survey shows that Wilkins' "Crane Channel" is this glacier, although it lies about 75 miles (120 km) northeast of the position originally reported by Wilkins.

<span class="mw-page-title-main">Erin Pettit</span> American glaciologist

Erin Christine Pettit is an American glaciologist focusing on climate change. She is an associate professor of geophysics and glaciology at Oregon State University. Her work focuses on ice-ocean interactions, ice-shelf disintegration, sea-level rise and ocean circulation changes.

<span class="mw-page-title-main">Liu Yan (scientist)</span> Chinese Antarctic researcher

Liu Yan is a Chinese Antarctic researcher best known for her work on iceberg calving. She is an associate professor of geography in the College of Global Change and Earth System Science (GCESS) and Polar Research Institute, Beijing Normal University.

<span class="mw-page-title-main">Marine ice sheet instability</span>

Marine ice sheet instability (MISI) describes the potential for ice sheets grounded below sea level to destabilize in a runaway fashion. The mechanism was first proposed in the 1970s by Johannes Weertman and was quickly identified as a means by which even gradual anthropogenic warming could lead to relatively rapid sea level rise. In Antarctica, the West Antarctic Ice Sheet, the Aurora Subglacial Basin, and the Wilkes Basin are each grounded below sea level and are inherently subject to MISI.

References

  1. "Thwaites Glacier Tongue". Geographic Names Information System . United States Geological Survey . Retrieved 23 October 2011.
  2. Douglas, Benn I.; Luck, Adrian; Åström, Jan A.; Crawford, Anna; Cornford, Stephen L.; Bevan, Suzanne L.; Gladstone, Rupert; Zwinger, Thomas; Alley, Karen; Pettit, Erin; Bassis, Jeremy. "Rapid fragmentation of Thwaites Eastern Ice Shelf, West Antarctica". Copernicus.org. Retrieved 2022-01-25.
  3. Kim, Jin-Woo; Kim, Duk-jin; Kim, Seung Hee; Ha, Ho Kyung; Lee, Sang Hoon (2015). "Disintegration and acceleration of Thwaites Ice Shelf on the Amundsen Sea revealed from remote sensing measurements". GIScience & Remote Sensing. 52 (4): 498–509. doi:10.1080/15481603.2015.1041766.
  4. 1 2 Cohen, Li (2021-12-14). "'Doomsday' glacier's last-remaining ice shelf could collapse within 5 years, and scientists warn it could rapidly raise sea levels". CBS News.
  5. Tinto, K; Bell, R (2011). "Progressive unpinning of Thwaites glacier from newly identified offshore ridge: Constraints from aerogravity". Geophysical Research Letters. doi: 10.1029/2011GL049026 .
  6. "Thwaites: Antarctic glacier heading for dramatic change". BBC News. 2021-12-13. Retrieved 2021-12-18.
  7. 1 2 3 Pettit, Erin C.; Wild, Christian; Alley, Karen; Muto, Atsuhiro; Truffer, Martin; Bevan, Suzanne Louise; Bassis, Jeremy N.; Crawford, Anna; Scambos, Ted A.; Benn, Doug (2021-12-15). Collapse of Thwaites Eastern Ice Shelf by intersecting fractures. AGU Fall Meeting. New Orleans: American Geophysical Union. C34A-07.
  8. Douglas, Benn I.; Luck, Adrian; Åström, Jan A.; Crawford, Anna; Cornford, Stephen L.; Bevan, Suzanne L.; Gladstone, Rupert; Zwinger, Thomas; Alley, Karen; Pettit, Erin; Bassis, Jeremy. "Rapid fragmentation of Thwaites Eastern Ice Shelf, West Antarctica". Copernicus.org. Retrieved 2022-01-25.
  9. Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder. "The Threat from Thwaites: The Retreat of Antarctica's Riskiest Glacier".
  10. Voosen, Paul (13 December 2021). "Ice shelf holding back keystone Antarctic glacier within years of failure". Science Magazine . Retrieved 2022-10-22. Because Thwaites sits below sea level on ground that dips away from the coast, the warm water is likely to melt its way inland, beneath the glacier itself, freeing its underbelly from bedrock. A collapse of the entire glacier, which some researchers think is only centuries away, would raise global sea level by 65 centimeters.
  11. Armstrong McKay, David; Abrams, Jesse; Winkelmann, Ricarda; Sakschewski, Boris; Loriani, Sina; Fetzer, Ingo; Cornell, Sarah; Rockström, Johan; Staal, Arie; Lenton, Timothy (9 September 2022). "Exceeding 1.5°C global warming could trigger multiple climate tipping points". Science. 377 (6611). doi:10.1126/science.abn7950. hdl: 10871/131584 . ISSN   0036-8075.
  12. Armstrong McKay, David (9 September 2022). "Exceeding 1.5°C global warming could trigger multiple climate tipping points – paper explainer". climatetippingpoints.info. Retrieved 2 October 2022.

PD-icon.svg This article incorporates public domain material from "Thwaites Ice Shelf". Geographic Names Information System . United States Geological Survey.