Miles of seawater run beneath the ‘Doomsday Glacier’



CNN

Sea water pushes down miles Antarctica’s “Doomsday Glacier” That makes it more vulnerable to melting than previously thought, according to new research that used radar data from space to X-ray the critical glacier.

As salty, relatively warm seawater meets the ice, it causes “radical melting” beneath the glacier. That means there are projections of global sea level rise Underestimated, according to a study published Monday in the Proceedings of the National Academy of Sciences.

Thwaites Glacier in West Antarctica – nicknamed the “Doomsday Glacier”. Collapsing sea levels can be catastrophic – It is the largest glacier in the world and the size of Florida. It is Antarctica’s most vulnerable and unstable glacier because the land it sits on slopes downward, allowing seawater to eat away at its ice.

Already contributing 4% to global sea level rise, the Thwaites hold enough ice to raise sea levels by more than 2 feet. But because it also acts as a natural dam for the surrounding ice in West Antarctica, Scientists have estimated Its complete collapse would eventually lead to about 10 feet of sea-level rise—a disaster for the world’s coastal communities.

Several studies have pointed to the enormous impacts of thwaites. Global warming driven by humans burning fossil fuels left it out hangs on “by its fingernails.” 2022 according to the study.

This latest research adds a new and alarming factor to predictions of its fate.

A team of glacier explorers led by scientists from the University of California, Irvine used high-resolution satellite radar data collected between March and June last year to create an X-ray of the glacier. This allowed Thwaites to create a picture of changes in the “grounding line”. Baselines are vital to ice stability, and a key point of vulnerability for thwaites, but difficult to study.

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“In the past, we only had sporadic data to look at this,” said co-author Eric Rignot, professor of Earth system sciences at the University of California, Irvine. study “In this new data set, we have solid observations of what’s going on, both daily and over months.”

Eric Rignot/UC Irvine

View of wave motion at Thwaites Glacier in West Antarctica recorded by Finland’s ICEYE commercial satellite mission based on images acquired on May 11, 12 and 13, 2023.

They observed that seawater was pushed under the glacier for miles and then escaped again following the daily rhythm of the tides. When the water flows, it only raises the surface of the glacier by centimeters, Rignot told CNN.

According to their research, he suggested that the term “grounding zone” may be more appropriate than grounding line, as it moves nearly 4 miles in a 12-hour tidal cycle.

The speed of seawater, which can move significant distances in a short period of time, increases glacier melting because as the ice melts, fresh water is washed away and replaced by warmer seawater, Rignot said.

“This process of widespread, massive seawater intrusion will increase sea-level rise projections from Antarctica,” he added.

Ted Scambos, a glaciologist at the University of Colorado Boulder who was not involved in the study, called the research “fascinating and important.”

“This discovery presents a process that has not yet been modeled,” he told CNN. Although these results apply to only certain areas of the glacier, he said, “it could accelerate the pace of ice loss in our projections.”

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Whether the flow of seawater under the Thwaites is a new phenomenon or something significant but long-unknown is an uncertainty that needs to be unraveled, said James Smith, a marine geologist with the British Antarctic Survey who was not involved in the study.

“Either way, it’s an important process that needs to be incorporated into ice models,” he told CNN.

Noel Cormelon, Professor of Earth Observation at the University of Edinburgh, said it was interesting to use radar data for this study. “Ironically, by going into space, using our growing satellite capabilities, we are learning more about this environment,” he told CNN.

There are still many unknowns about what the study’s findings mean for the future of Thwaites, said Gourmelen, who was not involved in the research. It’s unclear how widespread the process is around Antarctica, he told CNN, “although it’s very possible it’s happening elsewhere.”

Antarctica, an isolated and complex continent, appears increasingly vulnerable to the climate crisis.

By analyzing satellite data and using climate models, they found that “this is highly unlikely without the impact of climate change.”

In a separate study published on Monday, researchers from the British Antarctic Survey explored the reasons Record low extent of sea ice Around Antarctica last year.

Steve Gibbs/PAS

Sea ice around Rothera Point, Adelaide Island, west of the Antarctic Peninsula.

Sea ice melts Because it does not directly affect sea level rise It’s already floating, but This exposes coastal ice sheets and glaciers to waves and warm ocean water, making them more vulnerable to melting and breaking up.

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The researchers used climate models to predict the potential speed of recovery from such extreme sea ice loss and found that even after two decades, not all ice would return.

“The impact of Antarctic sea ice over two decades will be profound, including on local and global climate,” Louise Sime, co-author of the BAS study, said in a statement.

The findings add to evidence that the region has been facing “protracted regime change” over the past few years.

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