Doomsday Glacier in Antarctica is losing ice faster than it has been in the last 5,500 years

(ORDO NEWS) — The so-called Doomsday Glacier in Antarctica is shedding ice at the fastest rate in 5,500 years, raising concerns about the future of the ice sheet and the possibility of catastrophic sea level rise caused by melting ice on the frozen continent.

This conclusion was drawn from a study of prehistoric marine deposits found on the shores surrounding the Thwaites Glacier and neighboring Pine Island Glacier, located on the West Antarctic Ice Sheet.

Climate change-driven melting of Antarctica’s glaciers is occurring faster than at any time in recorded history, researchers report in the journal Nature Geoscience.

“These increased rates of ice melt may indicate that vital arteries in the heart of the West Antarctic Ice Sheet have been severed, leading to an accelerated flow into the ocean that is potentially catastrophic for future global sea levels in a warming environment,” he said in his study co-author Dylan Rude, a geoscientist at Imperial College London, said in a statement.

“Is it too late to stop this?” Rud asked. asked Rud.

As one of Antarctica’s fastest melting glaciers, Thwaites has been nicknamed the “Doomsday Glacier”. Since the 1980s, Thwaites has lost an estimated 595 billion tons (540 billion metric tons) of ice, contributing to a 4% rise in global sea levels.

Thwaites and its northern neighbor, the Pine Island Glacier, cover vast expanses: Thwaites has an area of ​​about 74,130 square miles (192,000 square kilometers) (which makes it almost as large as Great Britain) and Pine Island has an area of ​​62,660 square miles (162,300 square kilometers).

Because the seaward ends of the glaciers are located above a bowl-shaped ocean basin, both glaciers are exposed to warm, dense, salty water flows on the underside.

This warm water not only melts the glaciers where they enter the Amundsen Sea, but also undermines them from below, detaching them from their main anchorages located to the north.

In addition, this melting from below weakens the glaciers and makes them more prone to surface cracks, which can spread to the entire ice sheet and potentially lead to its collapse.

If the entire West Antarctic Ice Sheet were to collapse and melt into the sea, it would raise global sea levels by about 11 feet (3.4 meters).

To compare the rate of glacier melt today and in the distant past, scientists looked for clues on Antarctic beaches near where glaciers drain into the ocean.

Ice weighs down the land, so as some of this frozen mass melted and flowed into the sea towards the end of the last ice age (about 11,500 years ago), the land recovered, revealing coasts that were previously hidden under the waves.

By measuring the age and height of nearly two dozen coastlines, the scientists hoped to figure out how quickly the ice was disappearing from land before moving forward again.

The researchers determined the age of the coastlines by collecting ancient shells and tiny penguin bone fragments, then analyzed the ancient biomaterials using radiocarbon dating.

This method allows you to determine the age of organic material by measuring the amount of carbon-14, a radioactive isotope of carbon, or a variant with a different number of neutrons, which is found everywhere on Earth and is easily absorbed by plants and animals.

When animals die, they no longer accumulate carbon-14 in their tissues, and the amount they have already absorbed begins to decay.

The half-life of carbon-14 (or the time it takes for half of the carbon to decay) is 5,730 years, and scientists can accurately determine the age of animals that died thousands of years ago by measuring the amount of undecomposed carbon-14 in the remains.

By dating penguin bones and shells from more than 20 different coastlines, scientists have found that the oldest and highest beach began to form about 5,500 years ago.

From that point until about 30 years ago, ice loss exposed the shores at a rate of about 0.14 inches (3.5 millimeters) per year, the researchers said. But over the past three decades, the rate of coastline advance has increased dramatically – up to 1.6 inches (40 mm) per year.

“While these vulnerable glaciers have been relatively stable over the past few millennia, their current rate of retreat is accelerating and already raising global sea levels,” Rude said.

What this means for the future of Antarctica’s glaciers and ice sheet, as well as vulnerable coastlines around the world, remains unclear.

The researchers’ findings, while troubling, do not address the question of how many times glaciers may have retreated and transitioned to a new state over the entire history of observations.

Scientists hope to find out by drilling through the ice and taking rock samples from beneath it, which could show whether the current rate of melt is reversible or whether the glaciers have indeed passed the point of no return.


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