Scientists are warning of dramatic changes in one of Antarctica’s largest glaciers, potentially in the next five to ten years.
They say a floating section in front of the Thwaites Glacier that has so far been relatively stable could “break like a car windshield”.
Researchers from the United States and the United Kingdom are currently involved in an intense study program at Thwaites because of its melting rate.
It is already dumping 50 billion tons of ice into the ocean each year.
This is having a limited impact on global sea levels today, but there is enough ice trapped in the glacier’s watershed to raise sea levels by 65 cm — if everything melts.
This “doomsday” scenario is unlikely to happen for many centuries, but the study team says that Thwaites is now responding to a warming world in really very fast ways.
“There will be a dramatic shift on the glacier’s front, probably in less than a decade. Both published and unpublished studies point in that direction,” glaciologist Ted Scambos, chief US coordinator for the International Collaboration, tells BBC News of the Thwaites Glacier (ITGC).
“This will accelerate the pace (of thwaites thaw) and effectively expand the dangerous part of the glacier,” he adds.
Thwaites is a colossus. It’s about the size of Britain or Florida, and its melting speed has doubled in the last 30 years.
The ITGC showed how this dynamic is happening. It is the result of warm ocean water passing beneath—and melting—the Thwaites floating front, or ice shelf as it is known.
The hot water is thinning and weakening this ice, causing it to melt faster and pushing back the zone where the main glacier’s body becomes buoyant.
At present, the edge of the eastern ice shelf is held in place by an offshore subsea ridge, which means that its flow velocity is one-third of that observed in the western sector of the ice shelf, which has no such restriction.
But the ITGC team says the eastern shelf will likely detach from the crest in the next few years, which will destabilize it. And even if it doesn’t, the continued appearance of fractures in the ice shelf will almost certainly break the area anyway.
“I look at it in a similar way to a car window where you have some cracks that are slowly propagating and all of a sudden you go through a bump and the whole thing starts to break down in all directions,” explains Oregon State’s Erin Pettit University in the United States.
The affected area is very small when considered in the context of the glacier as a whole, but it represents a shift to a new regime, and more importantly what this means for further ice loss.
Currently, the eastern shelf, which is about 40 km wide, advances about 600 meters a year. The next change in status will likely cause the ice to jump in speed to about 2 km per year — the same as the current speed recorded in the 80 km wide western sector.
Jointly funded by the US National Science Foundation and the UK Natural Environment Research Council Research Council, the ITGC project, which will last five years, investigates Thwaites in minute detail.
Each summer in Antarctica, teams of scientists analyze the glacier’s behavior in every possible way. From satellite, on ice and from ships in front of Thwaites.
The teams have already started moving to start work in the new season that is about to start — some teams are still quarantined by Covid before starting the fieldwork in earnest.
One of the projects for the New Year will involve the small yellow submarine known as “Boaty McBoatface”.
Beneath Thwaites’ floating ice, it will collect data on water temperature, current direction and turbulence — all factors that influence the melt.
The autonomous vehicle will do missions lasting from one to four days, navigating its own way through the cavity below the platform.
This is a high-risk mission, as the seabed terrain is extremely uneven.
“It’s scary. We may not have Boaty back,” says Alex Phillips of the UK’s National Center for Oceanography.
“We’ve put a lot of effort over the past year in developing collision avoidance systems, to ensure that he doesn’t hit the sea floor. We also have contingency plans whereby if he gets into trouble he can retrace his steps and retreat safety. “
The latest studies on the Thwaites Glacier are being presented this week at the American Geophysical Union Autumn Meeting in New Orleans.
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