Glaciers everyone past Antarctica is in trouble if ice there melts quickly. There is no Antarctic glacier whose fate is more important to our future than the Thwaites glacier, and new research shows that things are not looking good for it.
Researchers have familiar that the Thwaites Glacier is in trouble because of the penetrating hot water, but that so far they have never analyzed data from beneath the glacier’s floating shelf. A new study published in Science Advances on Friday, offers the first direct observations ever of what goes under the infamous ice shelf, including the temperature and salinity of the water flowing beneath it, as well as the strength of the current.
What they found is quite worrying. The authors explain that the supply of hot water to the base of the glacier is greater than scientists previously believed, which means that it is even more unstable than we thought. Since it is often called the ‘doomsday glacier’, it is particularly ominous.
Thwaites Glacier is a broad, icy glacier that flows from the West Antarctic ice sheet into Pine Island Bay, part of the Amundsen Sea. The 193,000-square-kilometer (192,000-square-kilometer) ice shelf is disappearing much faster than any other one in the region due to the water circulating beneath it and deteriorating 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 two dozen scientists send an autonomous orange submarine Ran called among Thwaites. The underwater vehicle traveled two deep bowls under the glacier for 13 hours leading hot water there. The vehicle captured data showing that hot water – hot for a glacier, up to 1.05 degrees Celsius – up to 33.89 degrees Fahrenheit – revolves around the glacier’s important “fixed points”, or the points of contact where the ice shelf meets the rock that holds it in place. This hot water melts away these important spaces, leaving room for cracks and bowls in ice that can make the shelf all the more unstable.
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“The concern is that this water comes in direct contact with the bottom of the ice shelf at the point where the ice tongue and the shallow seabed meet,” said Alastair Graham, associate professor of geological oceanography at the University of South Florida, and co-studies author, who was on the research trip to the glacier, wrote in an email. ‘This is the last stronghold for Thwaites and once it opens up in front of the seabed, there is nothing else that can hold the ice shelf. That hot water probably also mixes in and around the baseline, deep in the cavity, and that means the glacier is also attacked at its feet where it rests on solid rock. ”
The discovery of hot water confirm previous concerns from a separate project, in which another group of 100 scientists drilled a 2,000-foot hole in the glacier.
“This study fills critical gaps in our knowledge in this area and will undoubtedly enable great progress in the modeling of this system, and thus improved projections,” said David Holland, a glacier from the University of New York, who told the previous study worked, but not the newer one, wrote in an email.
As the submarine moved around in one of the bins, it also captured data showing water with a low salinity in the area of 1,050 meters below the ice shelf. The salinity it showed is similar to that of neighboring Pine Island Bay. Scientists previously thought that this part of the glacier was protected by a thick underwater ridge against the bay’s currents. But they seem to have been wrong – the findings indicate that it flows freely in the trough. It connects its fate more closely to the bay than climate models are currently responsible for.
It’s also not just Pine Island Bay’s penetrating hot water. According to the submarine’s readings, the authors also mapped the canals along which hot water is transported to the Thwaites Glacier. They found that more warm water also flows along the continental shelf.
“Thwaites are really being attacked from all sides by the ocean,” Graham said.
All this has very serious consequences for those who live along the coast. The collapse of the Thwaites Glacier would increase sea level by 0.5 to 0.9 meters, and it could also cause a worse event. because it is the collapse of another nearby ice shelf, the Pine Island Glaciers. Together, these shelves serve as a brake mechanism on land ice that, if released into the open waters, it can push the sea up to 3.1 meters, overwhelming coastal cities around the world.
Over the past four decades, Graham explained, satellite data has shown that the glacier has flowed much faster into the ocean. Of course, it replenishes some when fresh snow falls and is squeezed into new ice, but it does not happen fast enough to make up for the losses.
To learn more about this process, scientists try to learn as much as possible about the glacier. Steering a submarine underneath is a big, groundbreaking step. But there is still a lot of uncertainty about how quickly it collapses.
The study illustrates the importance of climate adaptation measures, including weighing up the potential benefits to communities pull away from the coast. This is especially true because Graham said it is not entirely clear whether the downfall of the Thwaites is preventable.
“We (and I stress perhaps) have perhaps already reached a point and passed where there really is no stopping Thwaites, no matter what we as humans do to our climate,” Graham said.
Graham knows how cramped it is from the first hand, as he lives on the Gulf Coast of Florida. But not everything is lost.
‘There may be physical mechanisms that we have yet to uncover that can help stabilize Thwaites and ‘doomsday’ may never come, ‘he said.