A robotic submarine has returned from the dark underbelly of one of the Antarctic bigger glaciers with scary news – it might melt faster than we previously thought.
The Thwaites Glacier, a gigantic ice shelf in West Antarctica, has been on the radar of climatologists for two decades now. But they didn’t know how fast the glacier was melting, and how close it was to complete collapse, until researchers sent an unmanned submarine under the pack ice.
The first ever measurements in the dark waters beneath the 74,000-square-mile (192,000-square-kilometer) piece of ice revealed a disturbing tidbit: A previously underestimated hot water stream is flowing from the east, s ‘moving away in several vital pinning points. “which anchor the shelf to the ground.
Related: Time-lapse images of receding glaciers
“Our observations show that hot water is hitting from all sides at pinning points essential to the stability of the pack ice, a scenario that can lead to detachment and withdrawal,” the study authors wrote in l ‘article, published April 9 in the journal. Scientific progress. In other words, all the pack ice could break off and flow into the ocean.
As one of the fastest melting glaciers in Antarctica, the Thwaites Glacier, aptly dubbed the “Apocalypse Glacier,” has lost an estimated 595 billion tonnes (540 billion metric tonnes) of ice since then. the 1980s, since contributing to a 4% rise in sea level worldwide. time. The glacier acts like a cork in a wine bottle, preventing the rest of the region’s ice from draining into the sea, so the collapse of the Thwaites Glacier could potentially wash away the rest of the ice cap from the ‘West Antarctica with it, causing a 10-foot (3-meter) rise in global sea level.
“The concern is that this water will come in direct contact with the bottom of the pack ice at the point where the tongue of ice and the shallow seabed meet,” study co-author Alastair Graham, associate professor of oceanography geological at the University of South Florida, told Gizmodo.
This is terrible news for the glacier.
“This is Thwaites’ last stronghold and once it breaks away from the seabed at its very front, there is nothing else the Ice Shelf can hang onto. hot water is probably mixing in and around the ground line, deep in the cavity, and that means the glacier is also being attacked at its feet where it sits on solid rock, ”Graham told Gizmodo .
Located over 1,600 kilometers from the nearest research base, Thwaites is remote even by Antarctic standards. Scientists have already tested the temperatures around its edges, and even dropped a torpedo shaped robot through a 700m-deep hole in the ice, but this study marks the first time a submarine has entered the cavity under the shelf. The device, named Ran after the Norse goddess of the sea, measured the strength, temperature, oxygen content and salinity of ocean currents flowing under the glacier.
The ship’s sonar has also enabled high-resolution ocean mapping from the bottom of the cavity, helping scientists to visualize the paths the currents flow through and out. They spotted three main water inlets. One, a deep-water flow from the east, was once believed to be blocked by an underwater ridge, but Ran’s data shows the current is heading towards the bay. This means that currents enter the glacier from both sides, possibly eroding at its main anchor point, located to the north.
It is not clear how much melting is taking place, but researchers predict that just one of the currents alone is capable of shrinking ice at a rate of over 85 gigatons per year.
The results aren’t the only disturbing recent news to come from West Antarctica. Exposure to warmer water could also push the neighboring Pine Island Glacier of Thwaites past a tipping point, researchers showed in a study published March 25 in the Journal. The cryosphere. The 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, for the first time, the data needed to model the dynamics of the Thwaites Glacier,” says Anna Wåhlin, lead author of the study, professor of oceanography at Gothenburg University in Sweden, said in a press release. “These data will help us to better calculate ice melt in the future. With the help of new technology, we can improve models and reduce the great uncertainty that currently exists around global sea level variations.”
Originally posted on Live Science.