“Doomsday glacier” may not be melting as fast as feared – but it is still disappearing quickly, study shows
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Researchers have estimated that Antarctica’s “Doomsday Glacier” – predicted to cause devastating global sea level rise if it collapsed – is not melting as fast as previously thought, although it is still collapsing rapidly.
The Thwaites “Doomsday” Glacier.
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A United Nations climate panel predicted that in a worst-case scenario, the melting and eventual collapse of Antarctic ice sheets such as Thwaites Glacier – also known as Doomsday Glacier – would cause sea levels to rise dramatically worldwide: by three feet by 2070, by three feet by 2100, by three feet and by 50 feet by 2300.
This prediction is so serious because the UN researchers used a process called “marine ice cliff instability,” which predicts that warming oceans and the atmosphere could lead to increased melting at the glacier grounding line – the point at which glaciers begin to float.
But researchers from Dartmouth College cast doubt on that theory, saying MICI has not yet been actually observed. They added that the UN researchers used a single “low-resolution model” to test the process, according to a study published Wednesday in Science Advances.
Dartmouth College scientists tested the MICI process using three high-resolution models of Doomsday Glacier and found evidence that while the glacier is melting rapidly, it is not doing so as quickly as previously predicted and that a collapse is unlikely in the 21st century.
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“We are not saying that Antarctica is safe and that sea levels will not continue to rise – all our projections show a rapid retreat of the ice sheet,” said Mathieu Morlighem, a geoscientist at Dartmouth University and author of the study. “But sophisticated projections are important for coastal planning and we want them to be physically accurate.”
What is Doomsday Glacier?
The Thwaites Glacier in West Antarctica is nicknamed the Doomsday Glacier because its collapse could lead to the destruction of the West Antarctic Ice Sheet — which could cause devastatingly high sea levels, according to a Pennsylvania State University study. Climate change is increasing water temperatures in the Southern Ocean surrounding Antarctica, causing the glacier to melt rapidly. The glacier is the size of Florida and is the widest glacier in the world. It is also Antarctica’s most at-risk glacier because the land it sits on is sloping and warm ocean water can easily erode it over time. The melting glacier is already responsible for 10% of global sea level rise, but it is estimated that once it collapses, it could cause a global sea level rise of about two feet within a few years. For comparison, global sea levels have risen 8 to 9 inches since 1880. A sudden rise in sea levels could therefore have devastating consequences, particularly for low-lying and coastal cities such as New York, Miami, Shanghai and Mumbai, forcing some residents to move inland.
What other predictions are there for glacier collapse?
Although it’s difficult to predict exactly when the glacier will completely melt, researchers are using test models to predict when the collapse will occur. Scientists at the American Geophysical Union predicted in 2021 that a key section of the glacier could collapse within the next five years. Other researchers estimate that the glacier could collapse within the next 200 to 900 years, according to a study published in Science.
Important background
The Dartmouth researchers warn that overzealous estimates can negatively impact the lives of people in low-lying areas, as policymakers use these predictions to decide whether to build barriers or relocate communities entirely. According to Antionio Guiterres, the United Nations secretary-general, around 900 million people — or 10% of the world’s population — are at extreme risk from rising sea levels. Rising sea levels are already impacting coastal and low-lying cities. Taholah — an Indian village in Washington — announced plans in April to move half a mile away from the Pacific Ocean due to rising sea levels. Around 1,200 residents of the Panamanian island of Garbi Sugdub were forced to relocate to the mainland in February after the Caribbean Sea flooded the land. According to a 2020 PLOS One report, rising sea levels could force around 13 million Americans to relocate inland by 2100.
More information
Explaining the ‘Doomsday Glacier’: Why scientists believe it predicts a devastating sea level rise — that could happen sooner than thought (Forbes)
