Impact of Ocean Water Flowing Beneath the 'Doomsday Glacier' on Sea Level Rise

New research using radar data from space has revealed that ocean water is pushing miles beneath Antarctica’s “Doomsday Glacier,” making it more vulnerable to melting than previously believed.

When the salty, relatively warm ocean water meets the ice, it causes “vigorous melting” underneath the glacier. This discovery suggests that global sea level rise projections may have been underestimated. The study was published in the Proceedings of the National Academy of Sciences on Monday.

The Thwaites Glacier in West Antarctica is known as the "Doomsday Glacier" because its collapse could result in a catastrophic rise in sea levels. This glacier is the widest in the world and is approximately the size of Florida. It is also considered to be Antarctica's most at-risk and unstable glacier due to its location on sloping land, which allows ocean waters to erode its ice.

Thwaites Glacier is currently responsible for contributing 4% to the global rise in sea levels. It contains enough ice that, if melted, could raise sea levels by over 2 feet. Additionally, because it acts as a natural barrier for the surrounding ice in West Antarctica, scientists have warned that a complete collapse of Thwaites Glacier could potentially lead to a sea level rise of around 10 feet. This would have devastating consequences for coastal communities around the world.

The Thwaites Glacier in Antarctica, also known as the "Doomsday glacier" due to the huge risk its melting poses to global sea levels.

The Thwaites Glacier in Antarctica, also known as the "Doomsday glacier" due to the huge risk its melting poses to global sea levels.

NASA/OIB/Jeremy Harbeck

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Scientists have discovered surprising formations under the ice shelf of the so-called Doomsday Glacier, indicating that it is 'in trouble.' Many studies have highlighted the vulnerabilities of Thwaites, with global warming causing it to hang on "by its fingernails," as noted in a 2022 study.

A team of glaciologists, led by scientists from the University of California, Irvine, conducted a study using high resolution satellite radar data collected between March and June last year. This study aimed to create an X-ray image of the Thwaites glacier, focusing on changes to its "grounding line." Grounding lines are crucial for ice sheet stability and have been a challenging area to study.

"In the past, our data was sporadic," mentioned Eric Rignot, a professor at the University of California, Irvine, and a co-author of the study. "But now, with this new daily data set spanning several months, we have a clearer picture of what is happening."

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

A view of the tidal motion at Thwaites Glacier in West Antarctica was captured by Finland's ICEYE commercial satellite mission. The images were taken on May 11, 12, and 13, 2023. The photographs were analyzed by Eric Rignot from UC Irvine.

They saw seawater flowing beneath the glacier for many miles, and then flowing out again, following the daily tides. When the water comes in, it can lift the surface of the glacier by centimeters, as Rignot explained to CNN.

According to their study, the term "grounding zone" might be more suitable than grounding line, as it can shift almost 4 miles during a 12-hour tidal cycle.

The speed of the seawater plays a big role in melting glaciers quickly. When the ice melts, freshwater is replaced by warmer seawater, causing the glaciers to melt even faster, according to Rignot.

Rignot also mentioned that this extensive seawater intrusion will lead to higher estimates of sea level rise from Antarctica in the future.

Ted Scambos, a glaciologist at the University of Colorado Boulder, who was not involved in the study, found the research to be "fascinating and important." According to him, this new discovery reveals a process that has not been considered in current models. He also mentioned that although these findings are limited to specific glacier areas, they could potentially accelerate the rate of ice loss in future predictions.

One question that needs to be answered is whether the flow of seawater under Thwaites Glacier is a recent development or if it has been happening for a long time without us knowing, according to James Smith, a marine geologist at the British Antarctic Survey.

Smith, who was not part of the research team, emphasized the significance of understanding this phenomenon, stating that it is crucial for improving ice sheet models.

The floating ice edge at Thwaites Glacier margin, photographed in February 2019.

The floating ice edge at Thwaites Glacier margin, photographed in February 2019.

Robert Larter

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Scientists say that the 'Doomsday glacier' is at risk of raising sea levels by several feet and is currently holding on "by its fingernails."

Noel Gourmelen, a professor of Earth observation at the University of Edinburgh, finds the use of radar data for this study to be interesting. He pointed out that it is through advancements in satellite technology that we are able to learn more about this critical environment.

Gourmelen, who was not part of the research, mentioned that there are still uncertainties about the implications of the study's results for the future of Thwaites. He also highlighted that it is not clear how common this phenomenon is across Antarctica, but it is probable that similar processes are occurring in other areas as well.

A regime change

Antarctica, a remote and intricate continent, seems to be more at risk from the effects of climate change.

By examining satellite information and utilizing climate models, researchers discovered that this historic low temperature event would have been highly unlikely to occur without the impact of climate change.

In a different study published on Monday, researchers from the British Antarctic Survey examined the causes of the unusually low sea ice levels around Antarctica last year.

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

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

Steve Gibbs/BAS

Sea ice melting doesn’t cause sea levels to rise directly. This is because the ice is already floating. However, when the sea ice melts, it exposes coastal ice sheets and glaciers to waves and warm ocean waters. This makes them more likely to melt and break apart.

Researchers have also used climate models to forecast how quickly the ice could recover from such significant loss. Their findings show that even after twenty years, not all the ice will return.

Louise Sime, a co-author on the BAS study, mentioned that if Antarctic sea ice remains low for more than twenty years, it would have significant impacts on both local and global weather.

The authors of the study also pointed out that the findings contribute to the growing evidence suggesting that the region is undergoing a "lasting regime shift."

Editor's P/S:

The revelations in this article are deeply concerning, painting a grim picture of the vulnerability of Antarctica's glaciers to climate change. The discovery of ocean water flowing miles beneath the Thwaites Glacier, leading to vigorous melting, suggests that global sea level rise projections may have been too conservative. The potential collapse of this glacier, aptly named the "Doomsday Glacier," could have catastrophic consequences, raising sea levels by over 10 feet and displacing millions of people worldwide.

This study highlights the urgent need for action to mitigate climate change. As the Antarctic ice sheet continues to melt, it will not only contribute to rising sea levels but also disrupt ocean currents and weather patterns. The findings of this research emphasize the importance of reducing greenhouse gas emissions and investing in renewable energy sources to safeguard our planet's future.