A robotic submarine returned from the underground darkness of one of them From Antarctica the biggest glaciers with terrible news – they could melt faster than I thought before.
The Thwaites Glacier, a giant ice shelf in West Antarctica, has been on the radar of climate scientists for two decades. But they didn’t know how fast the glacier was melting and how close it was to collapsing completely, until researchers sent an unmanned submarine under the ice shelf.
The first measurements ever made in the dark waters beneath the 74,000-square-mile (192,000-square-kilometer) piece of ice revealed unsettling information: a previously underestimated stream of hot water is flowing from the east, moving away at several vital anchorages. “Which anchors the shelf of earth.
Related: Time-lapse images of retreating glaciers
“Our observations show that hot water influences from all sides the critical fixing points for the stability of the ice shelf, a scenario that can lead to decoupling and withdrawal,” wrote the study’s authors, which was published in the journal on April 9. Scientific advances. In other words, the entire ice shelf could come off and then flow into the ocean.
As one of the fastest melting glaciers in Antarctica, the Thwaites Glacier, happily nicknamed the “Doomsday Glacier”, has lost approximately 595 billion tons (540 billion metric tons) of ice since the 1980s, contributing to a 4-fold increase. % of global sea level each year. . The glacier acts like a cork in a bottle of wine, stopping the rest of the ice in the region from flowing into the sea, so the collapse of the Thwaites Glacier could take the rest of the West Antarctic ice sheet, causing a height of 10 feet (3 meters). ) rising global sea levels.
“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 study co-author Alastair Graham, an associate professor of geological oceanography at the University of Florida. South , he told Gizmodo.
This is terrible news for the glacier.
“This is the last fortress for Thwaites and once it comes off the seabed right in front of it, there is nothing else to hold the ice shelf on. This hot water also mixes in and around the ground line, deep in the cavity and that means the glacier is also attacked at its feet, where it rests on a solid stone, “Graham told Gizmodo.
Located more than 1,600 kilometers away from the nearest research base, Thwaites is far away even by Antarctic standards. Scientists have previously tested the temperatures around its edges and even a torpedo-shaped robot escaped through a 2,300-foot (700 m) hole in the ice, but this study marks the first time a submarine has entered the cavity below the shelf. The ship, named Ran after the northern goddess of the sea, measured the strength, temperature, oxygen content and salinity of ocean currents flowing under the glacier.
The ship’s sonar also allowed the high-resolution ocean mapping of the bottom of the cavity, helping scientists visualize the paths currents take and go. They saw three main streams of water. One, a deep stream of water from the east, was once thought to be blocked by an underwater ridge, but Ran data show that the current is making its way into the gulf. This means that currents flow into the glacier on both sides, possibly eroding it at its main anchorage point, located to the north.
It is not clear how much they are melting, but researchers predict that only one of the currents is able to reduce ice at a rate of over 85 gigatonnes per year.
The findings are not the only worrying recent news coming from West Antarctica. Exposure to warmer water could also push neighboring Pine Thwaites Glacier over a peak, researchers said in a study published March 25 in the Journal Cryosphere. Thwaites and Pine Island glaciers are currently responsible for 10% of the continued rise in global sea level, according to the Cryosphere study.
“The good news is that we are now collecting data for the first time to model the dynamics of the Thwaites Glacier,” said study author Anna Wåhlin, a professor of oceanography at the University of Gothenburg in Sweden. he said in a statement. “These data will help us better calculate ice melting in the future. With the help of new technologies, we can improve models and reduce the great uncertainty that now prevails around global sea level fluctuations. ”
Originally published on Live Science.