Scientists Find Record Warm Water in Antarctica, Pointing to Cause Behind Troubling Glacier Melt

Scientists Find Record Warm Water in Antarctica, Pointing to Cause Behind Troubling Glacier Melt

SOURCE: NYU DATE: January 29,2020 SNIP: A team of scientists has observed, for the first time, the presence of warm water at a vital point underneath a glacier in Antarctica—an alarming discovery that points to the cause behind the gradual melting of this ice shelf while also raising concerns about sea-level rise around the globe. The recorded warm waters—more than two degrees above freezing—flow beneath the Thwaites Glacier, which is part of the Western Antarctic Ice Sheet. The discovery was made at the glacier’s grounding zone—the place at which the ice transitions between resting fully on bedrock and floating on the ocean as an ice shelf and which is key to the overall rate of retreat of a glacier. Thwaites’ demise alone could have significant impact globally. It would drain a mass of water that is roughly the size of Great Britain or the state of Florida and currently accounts for approximately 4 percent of global sea-level rise. Some scientists see Thwaites as the most vulnerable and most significant glacier in the world in terms of future global sea-level rise—its collapse would raise global sea levels by nearly one meter, perhaps overwhelming existing populated areas. While the glacier’s recession has been observed over the past decade, the causes behind this change had previously not been determined. The scientists’ measurements were made in early January, after the research team created a 600-meter deep and 35-centimeter wide access hole and deployed an ocean-sensing device to measure the waters moving below the glacier’s surface. This device gauges the turbulence of the water as well as other properties such as temperature. The result...
Glacial melting in Antarctica may become irreversible

Glacial melting in Antarctica may become irreversible

SOURCE: The Guardian DATE: July 9, 2019 SNIP: Antarctica faces a tipping point where glacial melting will accelerate and become irreversible even if global heating eases, research suggests. A Nasa-funded study found instability in the Thwaites glacier meant there would probably come a point when it was impossible to stop it flowing into the sea and triggering a 50cm sea level rise. Other Antarctic glaciers were likely to be similarly unstable. Recent research found the rate of ice loss from five Antarctic glaciers had doubled in six years and was five times faster than in the 1990s. Ice loss is spreading from the coast into the continent’s interior, with a reduction of more than 100 metres in thickness at some sites. The Thwaites glacier, part of the West Antarctic ice sheet, is believed to pose the greatest risk for rapid future sea level rise. Research recently published in the Proceedings of the National Academy of Sciences journal found it was likely to succumb to instability linked to the retreat of its grounding line on the seabed that would lead to it shedding ice faster than previously expected. Alex Robel, an assistant professor at the US Georgia Institute of Technology and the study’s leader, said if instability was triggered, the ice sheet could be lost in the space of 150 years, even if temperatures stopped rising. “It will keep going by itself and that’s the worry,” he said. Modelling simulations suggested extensive ice loss would start in 600 years but the researchers said it could occur sooner depending on the pace of global heating and nature of the...
Huge cavity in Antarctic glacier signals rapid decay

Huge cavity in Antarctic glacier signals rapid decay

SOURCE: NASA and Science Alert DATE: January 30, 2019 SNIP: A gigantic cavity – two-thirds the area of Manhattan and almost 1,000 feet (300 meters) tall – growing at the bottom of Thwaites Glacier in West Antarctica is one of several disturbing discoveries reported in a new NASA-led study of the disintegrating glacier. The findings highlight the need for detailed observations of Antarctic glaciers’ undersides in calculating how fast global sea levels will rise in response to climate change. Researchers expected to find some gaps between ice and bedrock at Thwaites’ bottom where ocean water could flow in and melt the glacier from below. The size and explosive growth rate of the newfound hole, however, surprised them. It’s big enough to have contained 14 billion tons of ice, and most of that ice melted over the last three years. “[The size of] a cavity under a glacier plays an important role in melting,” said the study’s lead author, Pietro Milillo of JPL. “As more heat and water get under the glacier, it melts faster.” About the size of Florida, Thwaites Glacier is currently responsible for approximately 4 percent of global sea level rise. It holds enough ice to raise the world ocean a little over 2 feet (65 centimeters) and backstops neighboring glaciers that would raise sea levels an additional 8 feet (2.4 meters) if all the ice were...
Unprecedented U.S.-British project launches to study the world’s most dangerous glacier

Unprecedented U.S.-British project launches to study the world’s most dangerous glacier

SOURCE: The Washington Post DATE: April 30, 2018 SNIP: The largest U.S.-British Antarctic mission in seven decades officially launched at an event in Cambridge on Monday, as the two countries pooled dollars and scientific resources for missions to West Antarctica’s Thwaites glacier — a Florida-size ice body that, scientists fear, could flood the world’s coastlines in our lifetimes. “For global sea-level change in the next century, this Thwaites glacier is almost the entire story,” said David Holland, a geoscientist at New York University. Thwaites is wide and deep and flows out of the heart of West Antarctica, a marine ice sheet that could contribute about 10 feet of global sea-level rise. Thwaites is losing ice rapidly, with its 50 billion tons per year currently driving 4 percent of global sea-level rise, and sits perched in 2,600-foot-deep waters atop a seafloor “bump” that scientists fear is the last thing holding it in place. Thwaites is a key part of the reason that recent computer modeling studies have predicted that the Antarctic could double the previously projected rate of sea-level rise during this century. It’s among the most difficult places on Earth for humans to...
Ice Apocalypse

Ice Apocalypse

SOURCE: Grist DATE: November 21, 2017 SNIP: The glaciers of Pine Island Bay are two of the largest and fastest-melting in Antarctica. (A Rolling Stone feature earlier this year dubbed Thwaites “The Doomsday Glacier.”) Together, they act as a plug holding back enough ice to pour 11 feet of sea-level rise into the world’s oceans — an amount that would submerge every coastal city on the planet. For that reason, finding out how fast these glaciers will collapse is one of the most important scientific questions in the world today. In the past few years, scientists have identified marine ice-cliff instability as a feedback loop that could kickstart the disintegration of the entire West Antarctic ice sheet this century — much more quickly than previously thought. A wholesale collapse of Pine Island and Thwaites would set off a catastrophe. Giant icebergs would stream away from Antarctica like a parade of frozen soldiers. All over the world, high tides would creep higher, slowly burying every shoreline on the planet, flooding coastal cities and creating hundreds of millions of climate refugees. All this could play out in a mere 20 to 50 years — much too quickly for humanity to adapt. “It could happen faster or slower, I don’t think we really know yet,” says Jeremy Bassis, a leading ice sheet scientist at the University of Michigan. “But it’s within the realm of possibility, and that’s kind of a scary thing.” There’s a recurring theme throughout these scientists’ findings in Antarctica: What we do now will determine how quickly Pine Island and Thwaites collapse. A fast transition away from fossil fuels...