Thwaites Ice Shelf (), is an

Antarctic The Antarctic ( or , American English also or ; commonly ) 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 ...

ice shelf 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 ...

in the Amundsen Sea. It was named by ACAN after Fredrik T. Thwaites, a glacial geologist and

geomorphologist Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or ...

. The Thwaites Ice Shelf is one of the biggest

ice shelves 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 b ...

West Antarctica West Antarctica, or Lesser Antarctica, one of the two major regions of Antarctica, is the part of that continent that lies within the Western Hemisphere, and includes the Antarctic Peninsula. It is separated from East Antarctica by the Transant ...

, though it is highly unstable and disintegrating rapidly. Since the 1980s, the

Thwaites glacier Thwaites Glacier, nicknamed the Doomsday Glacier, is an unusually broad and vast Antarctic glacier flowing into Pine Island Bay, part of the Amundsen Sea, east of Mount Murphy, on the Walgreen Coast of Marie Byrd Land. Its surface speeds excee ...

, nicknamed the "Doomsday glacier", has had a net loss of over 600 billion tons of ice, though

pinning Pinning may refer to: * Pinning, the effect of certain weapons that cause their targets to be pinned down * Pinning ceremony (nursing), a symbolic welcoming of new graduates into the nursing profession * Pinning force, a force acting on a pinned ...

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 a slow melt rate, in contrast to the undefended western portion. According to the

American Geophysical Union The American Geophysical Union (AGU) is a 501(c)(3) nonprofit organization of Earth, atmospheric, ocean, hydrologic, space, and planetary scientists and enthusiasts that according to their website includes 130,000 people (not members). AGU's act ...

in a 2021 study, the Thwaites Eastern Ice Shelf (TEIS) buttresses one-third of

. Removal of the shelf has the potential to increase the contribution of

sea level rise Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cry ...

by up to 25%. Recent research shows that the ice shelf is 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

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 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. Complete melting of

is predicted to increase global sea levels by according to the

European Geosciences Union The European Geosciences Union (EGU) is a non-profit international union in the fields of Earth, planetary, and space sciences whose vision is to "realise a sustainable and just future for humanity and for the planet." The organisation has hea ...

, and the

Cooperative Institute for Research in Environmental Sciences The Cooperative Institute for Research in Environmental Sciences (CIRES) is a research institute that is sponsored jointly by the National Oceanic and Atmospheric Administration (NOAA) Office of Oceanic and Atmospheric Research (OAR) and the Un ...

states that the collapse of

could ultimately lead to sea-level rise of up to 3 meters if it draws the Pine Island and surrounding glaciers with it, due to

marine ice sheet instability 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 whi ...

. However, both of these processes would take time: a

Science Magazine ''Science'', also widely referred to as ''Science Magazine'', is the peer-reviewed academic journal of the American Association for the Advancement of Science (AAAS) and one of the world's top academic journals. It was first published in 1880, ...

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, and a 2022 assessment of

tipping points in the climate system In climate science, a tipping point is a critical threshold that, when crossed, leads to large and often irreversible changes in the climate system. If tipping points are crossed, they are likely to have severe impacts on human society. Tippin ...

stated that while the

West Antarctic Ice Sheet 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 ...

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.

References

{{usgs-gazetteer Ice shelves of Antarctica

See also

References