There’s a giant, hollowed-out cavity on the underside of a glacier that is likely to accelerate ice melt.
A team of scientists from Sweden, the United States and the UK set sail this week on a research ship to study the Thwaites Glacier in West Antarctica – and they expect to enlist the help of seals and other marine life to understand some of the sobering changes to the melting glacier.
Perhaps it’s not a moment too soon that they are.
An alarming study published Wednesday in Science Advances describes a giant, hollowed-out cavity on the underside of the glacier that is likely to accelerate ice melt and contribute to rising sea levels. “Several studies have suggested that the glacier is already in a stage of collapse and the retreat is unstoppable,” the authors from France, Germany and the U.S. acknowledged.
The glacier is about the size of Great Britain, but the hole on the underside of the glacier is big enough to hold 14 billion tons of ice and most of that has melted in the last three years. The new findings demonstrated a “size and explosive growth rate of the newfound hole” that they weren’t expecting, according to co-author Eric Rignot of the University of California, Irvine, and NASA’s Jet Propulsion Laboratory in Pasadena, where lead author Pietro Milillo also works.
It’s only visible now because of advanced satellite capacities, and that visibility has been a key problem in trying to understand the rate of melting and the role of topography on the undersea side of glaciers. It’s the reason for the 50-day journey of the International Thwaites Glacier Collaboration aboard the Nathaniel B. Palmer. The ship is leaving Punta Arenas, Chile, with 26 scientists and 31 crew and support staff on board, including climate writer Jeff Goodell.
“Thwaites is the cork in the wine bottle for the entire West Antarctic ice sheet. If it collapses, it could dump enough ice into the ocean to cause seas to rise by 10 feet or more,” Goodell wrote. “That would doom Miami, Boston, New York City, London, Shanghai, Jakarta — and virtually every other coastal city in the world. As Thwaites goes, so goes human civilization as we know it.”
To get at the problem, a team from University of Gothenburg will perform the first tests of the Swedish Autonomous Underwater Vehicle (AUV) designed to help researchers get a better handle on what Thwaites is doing – and what it’s likely to do in the future.
“Examining the seafloor and sediments at the glacier edge will provide an insight into how the ice has behaved in the past relative to records of environmental conditions,” said Robert Larter of the British Antarctic Survey, a marine geophysicist and chief scientist for the USD$25 million collaboration. “This is important for predicting how the glacier may respond to future climate change.”
Other team members will collect rocks, shells and penguin bones for carbon dating to understand sea levels in the past. Yet it’s the playful Antarctic seals, tagged with sensors, that may offer a “living window” into the underside of a glacier that scientists cannot see.
“Weddell and elephant seals like hanging out near the ice front or under sea ice, places we find really hard to access,” said seal ecologist Lars Boehme from University of St. Andrews. “The sensors record details about the seal’s immediate physical environment, which gives us a clearer picture of current oceanic conditions in these remote and inaccessible places.”