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Thwaites Glacier in Antarctica has been given the title of “Doomsday Glacier“It could flood coastlines around the world if they collapse. It already contributes about 4% of sea level rise per year With the loss of ice, one theory suggests that the glacier may soon melt. It starts to collapse into the ocean. Like a row of dominoes.
But is this kind of rapid collapse likely to happen as predicted? A new study into Thwaites Glacier's susceptibility to what is known as sea ice shelf instability It offers some hope. But Results Doesn't mean Thwaites is stable.
Arctic World Matthew MorlighemThe findings are explained by Dr. John Jordan, who led the study.
Why is Thwaites Glacier so important?
Thwaites Glacier drains a huge area of the Antarctic ice sheet – about 74,000 square miles This area covers 192,000 square kilometers, an area larger than the state of Florida. If a snowflake fell into this drainage system, it would eventually end up as part of an iceberg in the ocean off Thwaites River.
What we're seeing now with Thwaites Glacier is a slow-motion disaster.
The rocks beneath Thwaites Glacier lie below sea level. Sloping downwards towards the insideSo the glacier gets deeper towards the interior of the ice sheet. And once the glacier starts losing more ice than it's gaining from new snowfall and starts retreating, it's very difficult to slow it down because of this slope. And Thwaites has already started to melt. Declining at an accelerating rate As the climate warms.
Thwaites Glacier contains enough ice to raise global sea level by More than 2 feet (0.65 m). Once Thwaites begins to become unstable, he will destabilizing nearby glaciersSo what happens to Thwaites River affects the entire West Antarctic Ice Sheet, which in turn affects sea level rise along coasts everywhere.
What is sea ice slope instability?
Sea ice shelf instability is relatively new concept It was proposed by scientists in the last decade.
Many glaciers around Antarctica have huge floating extensions called Ice shelves which support glaciers and slow the flow of ice into the ocean. As the climate warms, we have seen some of these floating extensions collapse, sometimes too fastwithin a few weeks or months.
If the Thwaites Ice Shelf collapses, it will expose a very high ice shelf facing the ocean along its length. 75 miles (120 km) from the frontThe force that ice can withstand is limited, so if the shelf is too high, it will collapse into the ocean.
Once that happens, a new ice shelf will be exposed farther back, and the new shelf will be taller because it is located further inland. The theory of sea ice shelf instability suggests that if the cliffs collapse quickly enough, the new ice shelf will be exposed. It may have a domino effect. From the high ice cliffs that collapsed one after another.
But no one has noticed that the sea ice shelves are becoming unstable. And we don't know if that will happen, because a lot depends on how quickly the ice collapses.
What have you discovered about the risks threatening Thwaites?
when Sea ice shelf instability theory It was first introduced, and used as a rough approximation of how ice cliffs would collapse once the ice shelf disappeared.
Studies have since shown that Ice slopes will not fail systematically. Until the ice reaches about 442 feet (135 meters) high. Even at that point, it will collapse more slowly than expected and become much taller.
We used three high-resolution models to explore what this new physical understanding of ice slope instability might mean for Thwaites Glacier this century.
Our results show If the entire Thwaites Ice Shelf collapsed today, its ice front would not retreat inland as quickly because of the instability of the sea ice shelf alone. Without the ice shelf, the glacier's ice would flow more quickly toward the ocean, thinning the glacier's front. As a result, the ice cliffs would not be as high.
We found that Thwaites River will remain fairly stable at least until 2100. We also simulated the ice shelf collapse in 50 years, when ice grounding line – Where the land ice meets the ocean – it must retreat deeper inland. And even then, we found that sea ice shelf instability alone would not lead to rapid retreat.
These findings raise questions about some recent estimates of how quickly the Thwaites River could collapse. This includes the worst-case scenario cited in the Intergovernmental Panel on Climate Change report: Latest Evaluation Report But it is classified as “low probability”.
Thwaites is the glacier that everyone is worried about. If you model the entire ice sheet, this is where the sea ice shelf instability begins. Where it spreads far inlandSo if Thwaites River is not as at risk of icefall collapse as we thought, that's a good sign for the entire ice sheet.
But the instability of sea ice shelves is just one mechanism of ice loss. This discovery does not mean that Thwaites is stable.
What other reasons are causing glaciers to retreat at an accelerated rate?
There are many processes that make the Antarctic ice sheet unstable, some of which are well understood.
Ice-ocean interactions explain Most recent ice mass losses So far. Antarctica is very cold placeSo warming of the atmosphere doesn't have much of an effect yet. But warm ocean currents are flowing under the ice shelves, and they Thinning the ice from the bottomwhich weakens the ice shelves. When this happens, ice streams flow faster because there is less resistance.
Over the course of the last few decadesThe Amundsen Sea sector, where the Thwaites and Pine Island glaciers are located, has seen an intrusion of warm water from the Antarctic Current, which has been Defrost from below.
What does climate change have to do with it?
Antarctica may seem like a faraway place, but Human activities that are causing the planet to warm – Like burning fossil fuels – it has dramatic effects on the poles. Ice loss contributes to sea level rise, Impact on coastal areas All over the world.
People's choices today will determine how fast the water level rises.
This article was republished from Conversationan independent, nonprofit news organization that brings you reliable facts and analysis to help you make sense of our complex world. This article was written by: Matthew Morlighem, Dartmouth College
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Matthew Morlighem receives funding from NASA, the National Science Foundation, the Heising-Simons Foundation, and Dartmouth College.
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