Antarctica’s ‘Doomsday Glacier’ is in trouble, new data shows


Ran, the unscrewed submarine the scientists used, heading deep into the Thwaites Glacier.

Ran, the unscrewed submarine the scientists used, heading deep into the Thwaites Glacier.
Photo: Filip Stedt (fake images)

Glaciers all on Antarctica are in trouble like ice there melts quickly. There is no Antarctic glacier whose fate has more consequences for our future than the Thwaites Glacier, and new research shows that things are not looking good for it.

Researchers have known that the Thwaites Glacier is in trouble due to the invasion of warm waters, but they had never analyzed data from underneath the glacier’s floating ice shelf – until now. TO new study published in Science Advances on Friday presents the first direct observations of what is happening under the infamous ice shelf, including the temperature and salinity of the water flowing under it, as well as the strength of the current.

What they found is quite disturbing. The authors explain that the hot water supply to the base of the glacier is greater than scientists previously believed, which means that it is even more unstable than we think. Given that it is often called the “glacier at the end of the world,” that is particularly sinister.

The Thwaites Glacier is a large chunk of ice that flows from the West Antarctic Ice Sheet to Pine Island Bay, a part of the Amundsen Sea. The 119,300-square-mile (192,000-square-kilometer) ice shelf is disappearing faster than any other in the region, in large part due to waters circulating beneath it and wearing away at its base. If it collapses completely, it could have a devastating effect on global sea level rise.

The new study is based on field observations from 2019 when a team of two dozen scientists sent a freelance orange submarine called Ran down under Thwaites. For 13 hours, the underwater vehicle traveled around two channels deep under the glacier that funnel warm water into it. As it did so, the vehicle captured data showing that warm water (warm for a glacier, up to 33.89 degrees Fahrenheit (1.05 degrees Celsius)) swirls around the glacier’s crucial “fixation points,” or contact points where the ice shelf is. finds the bedrock that holds it in place. This warm water is melting these crucial cellars, leaving room for cracks and channels in the ice that can make the shelf even more unstable.

“The concern is that this water is coming into direct contact with the bottom of the ice shelf at the point where the ice tongue and the shallow seafloor meet,” Alastair Graham, associate professor of geological oceanography at the University. South Florida co-study author, who was on the glacier research expedition, wrote in an email. “This is the last stronghold on Thwaites and once it breaks off the seafloor in front of it, there is nothing else to hold onto the ice shelf. The warm water is also likely mixing in and around the grounding line, deep into the cavity, and that means the glacier is also being attacked at its feet, where it rests on solid rock. “

The discovery of warm water confirms previous concerns from a separate project, in which another group of 100 scientists drilled a 600-meter hole in the glacier.

“This study fills critical gaps in our knowledge in this area and will undoubtedly allow important advances in the modeling of this system and, therefore, better projections,” David Holland, New York University glaciologist who worked on the previous study but not the newest, he wrote in an email.

As the submarine moved around one of the channels, it also captured data showing low salinity water in the area 3444 feet (1050 meters) below the ice shelf. That salinity level it showed matches that of neighboring Pine Island Bay. Scientists previously thought that this part of the glacier was protected from the currents of the bay by a thick underwater ridge. But it seems they were wrong: the findings indicate that it flows freely into the canal. That ties their fate closely to the bay more than climate models currently explain.

We don’t just have to worry about the warm waters of Pine Island Bay. Using the submarine’s readings, the authors also mapped the channels along which warm water is transported to the Thwaites Glacier. They found that more warm water is also entering along the continental shelf..

“Thwaites is really being attacked by the ocean from all sides,” Graham said.

All of this has very serious consequences for those who live along the coast. The collapse of the Thwaites Glacier would raise the sea level by 1.5 to 3 feet (0.5 to 0.9 meters) and could also trigger an even worse chain of events. because it could initiate the collapse of another nearby ice shelf in danger, the Pine Island Glacier. Together, these shelves act as a braking mechanism in land ice that, if released into open water, it could push the seas up to 10 feet (3.1 meters), overwhelming coastal cities around the world.

For the past four decades, Graham explained, satellite data has shown that the glacier has been flowing into the ocean much faster. Sure, it replenishes something when fresh snow falls and compacts into fresh ice, but that’s not happening fast enough to make up for its losses.

To learn more about this process, scientists are trying to learn everything they can about the glacier. Sending a submarine underneath marks a great revolutionary step. But there is still a lot of uncertainty about how fast it is approaching collapse.

The study illustrates the importance of climate adaptation measures, including weighing the potential benefits of having communities withdraw from the shores. That’s especially true because Graham said it’s not entirely clear whether or not the Thwaites’ disappearance can be prevented.

“We could (and I emphasize that we could) have reached and passed a point where there really is no turning back for the Thwaites, no matter what we as humans do with our climate,” Graham.

Graham knows how scary this is firsthand as he lives on the Gulf Coast of Florida. But not all is lost.

“Can They will be physical mechanisms that we have not yet discovered and that could help the Thwaites stabilize and it is possible that ‘doomsday’ will never come, “he said.

.

Source link