New research shows how warmer oceans, driven by climate change, are gouging the West Antarctic’s Thwaites Glacier.
Antarctica’s Thwaites or “doomsday” glacier is so named because of the huge risk its melting poses to global sea levels. The glacier is roughly the size of the state of Florida and has been the subject of massive amounts of research, over the years.
The glacier is located in West Antarctica. Part of what holds it in place is an ice shelf that juts out onto the surface of the ocean, and it acts like a cork, holding the glacier back on the land and providing an important defense against sea level rise.
Previous studies have found that the glacier could collapse within 100 years, and meltwater from the mass of ice could raise global sea levels by up to 2 feet.
You have heard of the analogy about the “canary in the coal mine.” Miners used to have caged canaries (birds) they would carry down into the mine tunnels with them. If dangerous gases such as carbon monoxide collected in the mine, the gases would kill the canary before killing the miners.
Thwaites Glacier is considered the canary in the coal mine for the consequences of global warming — a bellwether of the changing planet.
The warming ocean is cutting into the underside of the glacier
New research, reported in two separate papers published Wednesday in the journal Nature, will help scientists better estimate what will likely happen as the glacier thins and paint a more detailed picture of how Thwaites is changing as a whole.
Using an underwater robot at Thwaites Glacier, researchers have determined that warm water is getting channeled into crevasses in what the researchers called “terraces” — basically, upside-down trenches — and carving out gaps under the ice, reports the Washington Post.
This means that as the ice then flows toward the sea, these channels enlarge and become spots where the floating ice shelf can break apart and produce huge icebergs. If the remaining shelf is further undermined, Thwaites Glacier will flow into the ocean faster and boost global sea levels on a large scale.
The overlapping studies involved more than two dozen scientists from the International Thwaites Glacier Collaboration, a historic scientific collaboration organized by the United States and the United Kingdom
The research took place between 2019 and 2020 and necessitated drilling down 2,000 feet with a hot water drill in order to deploy an ocean sensor at the base of the floating ice shelf and sent down a pen-shaped, 11-foot-long robot called Icefin.
The vessel collected data and images in an environment in which warm ocean water, in some places was more than 2 degrees Celsius above the local freezing point, and this temperature variation is weakening the glacier.
The warm water entering Thwaites Glacier’s crevasses poses a serious threat, according to Britney Schmidt, a Cornell University scientist who is the lead researcher behind Icefin and deployed it with a group of 12 other researchers who encamped on the ice.
“The warm water is getting into the weak spots of the glacier, and kind of making everything worse,” Schmidt said. “It shouldn’t be like that,” Schmidt continued. “That’s not what the system would look like if it wasn’t being forced by climate change.”
“The crevices are basically funneling warm water faster than other parts of the glacier system,” Schmidt said. “So, the crevasses are not just weaknesses in terms of cracks in the ice, but they are becoming these giant features, and that process starts right at the grounding line.”
Thwaites is some 80 miles across and is the exit point for an area of ice larger than Florida. It is, essentially, the heart of West Antarctica, so large that if lost, it could be replaced only by a new Thwaites Sea.
The rate of loss overall since 1979 has been a little less than 20 billion tons per year, but that has increased to more than 40 billion tons since 2010, according to the data Rignot provided.
There was some good news in the research: In areas measured beneath Thwaites that were not characterized by crevasses and terraces, the melt rates were fairly slow.
This good news was discussed n the second study published in Nature. Peter Davis of the British Antarctic Survey said researchers found that a layer of freshwater between the bottom of the ice and the ocean actually helps stabilize flat parts of the ice shelf.
“They’re still changing very quickly, but this helps us understand why some parts of the glacier act one way and other parts act another way,” Schmidt said.
The two research papers published in Nature are as follows:
Suppressed basal melting in the eastern Thwaites Glacier grounding zone
