Thwaites Glacier

Thwaites Glacier
"Doomsday Glacier"
Thwaites Glacier
Type	Tidewater valley
Location	Walgreen Coast, Marie Byrd Land, Antarctic
Coordinates	75°30′S 106°45′W / 75.500°S 106.750°W / -75.500; -106.750
Area	192,000 km2 (74,000 sq mi)[1]
Width	120 km (75 mi)[2]
Thickness	800–1,200 metres (0.50–0.75 miles)[1]
Lowest elevation	Below sea level
Terminus	Pine Island Bay, part of the Amundsen Sea
Status	Receding

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.^[1][3] 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 (31 and 62 mi) east of Mount Murphy.^[1] 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.

Thwaites Glacier is closely monitored for its potential to elevate sea levels.^[4] Since the 1980s, Thwaites and Pine Island Glacier have been described as part of the "weak underbelly" of the West Antarctic Ice Sheet, in part because they seem vulnerable to irreversible retreat and collapse even under relatively little warming, yet also because if they go, the entire ice sheet is likely to eventually follow.^[5][6][7] This hypothesis is based on both theoretical studies of the stability of marine ice sheets and observations of large changes on these two glaciers. In recent years, the flow of both of these glaciers has accelerated, their surfaces have lowered, and their grounding lines have retreated.^[8] They are believed very likely to eventually collapse even without any further warming.^[9][10][11] The outsized danger Thwaites poses has led to some reporters nicknaming it the Doomsday Glacier,^{[12][13][14][15][16]} although this nickname is controversial among scientists.^[17]

The Thwaites Ice Shelf, a floating ice shelf which braces and restrains the eastern portion of Thwaites Glacier, is likely to collapse within a decade from 2021.^{[5][18][19][20]} The glacier's outflow is likely to accelerate substantially after the shelf's disappearance; while the outflow currently accounts for 4% of global sea level rise, it would quickly reach 5%, before accelerating further. The amount of ice from Thwaites likely to be lost in this century will only amount to several centimetres of sea level rise,^[1][21] but its breakdown will rapidly accelerate in the 22nd and 23rd centuries,^[10] and the volume of ice contained in the entire glacier can ultimately contribute 65 cm (25+1⁄2 in) to global sea level rise,^[5] which is more than twice the total sea level rise to date.^[22] Some researchers have proposed engineering interventions to stabilize the glacier,^[10][23][24] but they are very new, costly and their success uncertain.^[25]