Thwaites Glacier in Antarctica “is holding on by its fingernails,” experts say, after discovering it has been retreating at twice the rate previously thought in the past 200 years.
The West Antarctic glacier – which is about the size of Florida – has been an important consideration for scientists trying to make predictions about global sea level rise.
The potential impact of its retreat is huge, as a complete loss of Thwaites and the surrounding ice basins could raise global sea levels by as much as 10 feet.
For this reason, it is nicknamed the “doomsday glacier”.
For the first time, scientists have mapped a critical area of the seafloor off Thwaites in high resolution, giving them a glimpse of how rapidly the glacier retreated and moved in the past.
The stunning images reveal geological features new to science and also offer a crystal ball of sorts to peer into Thwaites’ future, according to experts at the University of South Florida’s College of Marine Science.
The study suggests that the glacier could experience large changes in small timescales in the future.
Alarmingly, analysis of the new images shows that the rate of withdrawal of Thwaites that scientists have documented more recently is slow compared to the fastest rates of change in the past.
The team documented more than 160 parallel ridges that formed like a footprint as the glacier’s leading edge retreated and swayed up and down with the daily tides.
Worrying times: Thwaites Glacier in Antarctica is ‘holding on by its fingernails’, experts say, after discovering it has been retreating at twice the rate previously thought over the past 200 years
For the first time, scientists have mapped a critical area of the seafloor off Thwaites (pictured) in high resolution, giving them a glimpse of how rapidly the glacier retreated and moved in the past
“It’s like looking at a tide gauge on the sea floor,” said geophysicist Alastair Graham.
“I’m really blown away by how beautiful the data is.
To understand Thwaites’ past retreat, the researchers analyzed the ridge-like formations submerged just under half a mile (700 m) below the polar ocean and accounted for the tidal cycle for the region, as predicted by computer models, to show that a Rib must be formed every day.
Sometime in the past 200 years, the face of the glacier lost contact with a seafloor ridge for less than six months and retreated at a rate of more than 1.3 miles (2.1 km) per year — twice the rate documented using satellites between 2011 and 2019.
“Our results suggest that very rapid pulses of retreat have occurred at Thwaites Glacier over the last two centuries and possibly as late as the mid-20th century,” Graham said.
Marine geophysicist and study co-author Robert Larter, of the British Antarctic Survey, added: “Thwaites is really holding onto his fingernails today and we should expect big changes in small timescales – even from a year to the future – in the future.” next next – as soon as the glacier retreats over a flat ridge in its bed.’
To collect the imagery and supporting geophysical data, the team, which included scientists from the US, UK and Sweden, launched a state-of-the-art orange robotic vehicle loaded with image sensors during a 2019 expedition.
It mapped an area of seafloor in front of the glacier the size of Houston in extreme conditions during an unusual summer notorious for its lack of sea ice.
This allowed scientists access to the glacier front for the first time in history.
To collect the imagery and supporting geophysical data, the team, which included scientists from the US, UK and Sweden, launched a state-of-the-art orange robotic vehicle (pictured) loaded with imaging sensors during a 2019 expedition
Scientists Robert Larter (left) and Alastair Graham (right) gaze in awe at the crumbling ice wall of Thwaites Glacier
The research vessel R/V Nathaniel B. Palmer was photographed by drone on the ice front of Thwaites Glacier in February 2019
“This was a groundbreaking study of the seafloor, made possible by recent technological advances in autonomous ocean mapping and a bold decision by the Wallenberg Foundation to invest in this research infrastructure,” said Anna Wåhlin, a physical oceanographer from the University of Gothenburg, who used Rán on Thwaites.
“The images Ran collected give us important insights into the processes occurring at the critical junction between the glacier and the ocean today.”
Graham, who described it as a “once-in-a-lifetime mission,” said the team would like to directly sample the seafloor sediments so they can more accurately date the ridge-like features.
“But the ice was coming at us pretty quickly and we had to go before we could do that on this expedition,” he added.
According to the United Nations, about 40 percent of humanity lives within 60 miles of the coast.
“This study is part of a multidisciplinary collective effort to better understand the Thwaites Glacier system,” said Tom Frazer, dean of the USF College of Marine Science, “and just because it’s out of sight doesn’t mean we can have Thwaites outside of it.” mind.
“This study is an important step forward in providing essential information for global planning efforts.”
The study was published in the journal Nature Geoscience.
THE RETREAT OF THE THWAITES GLACIER
The Thwaites Glacier is slightly smaller than the overall size of the United Kingdom, about the size of Washington state, and is located in the Amundsen Sea.
It is up to 4,000 meters (13,100 feet) thick and is considered key to projections of global sea level rise.
The glacier is retreating in the face of the warming ocean and is considered unstable because its interior is more than two kilometers (1.2 miles) below sea level, while the coastal glacial floor is fairly flat.
Thwaites Glacier is the size of Florida and is in the Amundsen Sea. It is up to 4,000 meters thick and holds the key to projections of global sea level rise
Thwaites Glacier has experienced significant flow acceleration since the 1970s.
From 1992 to 2011, the center of the Thwaites ground line retreated nearly 14 kilometers (nine miles).
Since 1973, annual ice runoff from this region has increased by 77 percent overall.
Because its interior connects to the large portion of the West Antarctic Ice Sheet that lies well below sea level, the glacier is thought to be the gateway to most of West Antarctica’s potential contribution to sea level.
The collapse of Thwaites Glacier would result in global sea level rise of between one and two meters (three and six feet), with the potential for it to be more than twice that of the entire West Antarctic Ice Sheet.
