Critical Antarctic Ice Shelf May Break in Next Five Years

As the planet rapidly heats and changes the landscape of the northern Arctic region, scientists have discovered disturbing and alarming signs in the far south of the planet, particularly on one of the ice shelves that protect Antarctica’s so-called “Doomsday glacier”.

Satellite images taken last month, which the researchers presented at the annual meeting of the American Geophysical Union on Monday (13), suggest that the critical ice shelf that holds the Thwaites glacier in western Antarctica together – an important defense against global sea level rise – could break within the next three to five years.

Antarctica’s Thwaites Glacier is known as the “Doomsday Glacier” because of the serious risk it poses during its melting process. It dumped billions of tons of ice into the sea and its disappearance could lead to irreversible changes across the planet.

The glacier, which is the equivalent size of Florida or Great Britain, already accounts for about 4% of the annual rise in global sea level, loses about 50 billion tons of ice each year and is becoming very high. vulnerable to the climate crisis. The fall of the ice shelf could cause the glacier to collapse imminently.

If the Thwaites collapse, the event could raise sea levels by several meters, the researchers say, putting coastal communities as well as low-lying island nations at risk.

But Ted Scambos, a glaciologist at Colorado Boulder University and leader of the Thwaites Glacier International Collaboration, said it will still be decades before the world sees a real acceleration and further rise in sea level rise.

“What strikes Thwaites is that change will continue with very dramatic and measurable results in the coming decades,” Scambos told CNN.

For now, the glacier is being held back by a critical floating ice shelf.

“What’s most worrying about the recent results is that they point to a collapse of this ice shelf, this kind of safety band that keeps the ice on land,” said Peter Davis, an oceanographer for the British Antarctic Survey, to CNN. “If we lose this ice shelf, the glacier will flow into the ocean more quickly, contributing to sea level rise.”

Warming ocean waters play a key role in rapid deterioration. A 2020 study by the Thwaites Glacier International Collaboration, which is currently leading ongoing research in Antarctica, found that the ocean floor is deeper than scientists thought, with deep passages allowing warm ocean water to melt the bottom. of ice.

Observations show that the critical ice shelf holding the Thwaites together is loosening its grip on the underwater mountain, or seamount, which acts as a reinforcement against the river’s ice flow into the warm ocean. The researchers also found that the so-called “ice tongue” of the Thwaites glacier is now simply a “loose clump of icebergs”, which no longer influences the stable part of the eastern ice shelf.

Hot water also threatens the so-called “landing zone”, where ice meets the sea floor. Davis and his team used hot water to drill access holes in the surface of the ice shelf and deep in the ocean cavity. In doing so, they found that not only are the ocean waters at the shoreline warm, by polar standards, but they are also salty, preparing the landscape for further erosion.

Peter Washam, a research associate at Cornell University who is also involved in the research, said the physical characteristics of the landfill zone show signs of chaos, such as hot water, rough ice and a steep, sloping bottom that allows the water to melt. quickly the ice sheet underneath.

“Over the next few years, we expect the Thwaites earth line in the region to slowly recede into the seafloor slope it currently stands on, as the warm ocean eats away at its underside,” Washam told CNN. His team used an underwater vehicle called the Icefin, which makes it easier to study the ice and water around and below the ice shelves.

The end result, according to Davis, is that Antarctica’s Thwaites Glacier is rapidly deteriorating. Warm ocean water is slowly erasing the ice underneath, causing the water to flow faster, breaking the ice further and bringing the threat of collapse even closer.

“From the satellite data, we are seeing these large fractures spreading across the surface of the ice shelf, essentially weakening the ice fabric; kind of like a crack in the windshield,” he said. “It’s slowly spreading across the ice shelf and will eventually break into several different pieces.”

Scambos said that while the process is extremely slow and the real impacts aren’t felt until several decades later, it’s nearly impossible to stop.

“This is a geological process, but it’s happening on almost a scale of human life,” he said. “As a disaster for people alive today, it’s extremely slow. The best way is to try to slow down the forces that are pushing the ice in that direction.”

And as the ramifications of the climate crisis spread across the globe, researchers say expanding scientific research to understand changes in the Arctic and Antarctic regions is critical to planning mitigation strategies such as coastal defenses in vulnerable communities.

“We can’t do anything to stop that from happening,” other than slowing down, Davis said. “The way we’ve done our carbon emissions so far has caused these changes – and essentially we’re suffering the consequences of what we’ve been emitting for the past two decades, if not more.”

Translated text. Read the original in English.