It sounds like a script for a new sci-fi movie. An international team of scientists is racing to Antarctica. Once they arrive, they will drill through a half kilometer of ice using a jet of hot water, then enlarge the hole so they can insert a high tech submarine that is shaped like a torpedo into the water beneath the ice to see why the ice is melting at an ever faster rate. Once the hole is open, they will have only a limited time to complete the insertion before it refreezes.
But it’s not a movie script. The submarine is real and the team of scientists has already reached the Thwaites Glacier, which is one of the most remote locations on the world’s most remote continents. They will be dragging high tech sleds across the ice to determine precisely where it leaves the land and starts floating on the Southern Ocean that surrounds Antarctica.
Recent research suggests the Thwaites Glacier has already lost 540 billion tons of water in the past 40 years and the rate of melting is getting faster, according to a report in The Guardian. “There are several glaciers in Antarctica that are doing similar things, but this is the one we are most worried about,” says David Vaughan, the director of science at the British Antarctic Survey, and part of the joint UK/US research team. “The aim is to do it as rapidly as possible. All of this will happen in three to four days. They really can’t afford to muck about,” adds Vaughan. The researchers will be on the glacier until March of next year.
The Thwaites Glacier is about the size of Florida. Earlier this year, NASA scientists using ground penetrating radar, discovered an enormous cavern two-thirds the size of Manhattan and 300 meters high on the underside of the glacier. The theory is that warmer water is accumulating beneath the glacier and acting much like the pot of boiling water people used to put in the freezer compartment of their refrigerators to defrost them. (Many of you are too young to remember a time before frost-free refrigerators became the norm.)
“Nobody has ever been able to drill through the ice close to where it starts to float and that is the critical point,” Vaughan tells The Guardian. “If everything goes to plan, they will drill the hole and then ream it out until it’s about 50 cm across, and then lower in the autonomous underwater vehicle. That will actually go into the cavity and send back images in real time so they can navigate it right up to the point where the ice starts to float.”
The submarine is just over 10 feet long and is outfitted with high definition cameras, sonar, and instruments for monitoring water flow, salinity, oxygen, and temperature. These can determine how much fresh water is flowing out from under the ice shelf. The robotic sub will also sample the gritty sediment shed into the water as the glacier grinds over the slab of rock it sits on. The data will feed into computer models to refine predictions about the fate of the glacier and the magnitude of sea level rise its melting will produce.
Melting of the Thwaites glacier is already responsible for about 4% of the global sea level rise. If all the ice in the glacier were to melt, average sea levels would rise more than 2 feet. That’s bad but the real concern is that it holds back other inland glaciers and prevents them from reaching the ocean where melting begins. If all that inland ice were to melt, ocean levels would rise about 7 feet, wreaking havoc on coastal areas around the globe.
“If Thwaites glacier melts on its own, we will see a rise in sea level around our own coast,” says Vaughan. “We are not saying that it’s going to happen in the next 100 years or so, but it could certainly begin in that time period. We’ll look at the flow of the ice and see how it’s affected, for instance, by tidal changes. All of those things tell us about the sensitivity of the system to small perturbations, which in future might be large perturbations as the ice shelf melts. This is all about sea level rise. That is why we are here.”
If the researchers have the same results as those studying the ice cap in the Arctic, the pace of change may be accelerating far more quickly than anyone realizes.
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