Seawater seeps into the Doomsday Glacier. Researchers warn of dire consequences of rising ocean levels

Ocean water is seeping miles beneath Antarctica's 'Doomsday Glacier', making it more vulnerable to melting ice than previously thought. This revelation comes from a new study that used space-based radar data to examine this important glacier in detail.

The investigation was published in the magazine Proceedings of the National Academy of SciencesIt reveals that warm, relatively salty ocean water is causing “strong melting” at the base of the Thwaites Glacier. This merger may mean that current predictions about sea level rise have been underestimated.

Thwaites Glacier, located in West Antarctica and known as the “Doomsday River”, is the largest glacier in the world, with an area similar to the size of the state of Florida in the United States. Its location is particularly vulnerable, because it is located in an area where the land slopes downward, allowing ocean water to erode the ice.

Thwaites currently contributes 4% to global sea level rise. It contains enough ice to raise sea levels by more than 60 cm. However, since it also acts as a natural dam for the surrounding ice in West Antarctica, its complete collapse could cause sea levels to rise by about 3 metres, a disastrous situation for the world's coastal communities.

Scientists have long warned of Thwaites' vulnerability. According to a 2022 study, global warming, caused by the burning of fossil fuels, has left the glacier “hanging on by its fingernails.”

A team of glaciologists from the University of California, Irvine led the latest research. Using high-resolution satellite radar data collected between March and June last year, they were able to create a detailed X-ray image of the glacier. This method allowed them to observe changes in the 'ground line' of Thwaites Island, the point where the glacier rises from the sea floor and becomes a floating ice shelf.

“In the past, we only had sparse data to analyze this issue,” said Eric Renaud, a professor of Earth system sciences at the University of California and co-author of the study, which was reported by CNN International. “In this new set of data, presented daily and over several months, we have powerful observations of what is happening.”

The researchers noticed that seawater seeps under the glacier and follows the daily rhythm of the tides. Seawater seepage is enough to “raise” the glacier's surface by a few centimetres, according to Renew.

The speed at which seawater moves quickly under the glacier accelerates the melting of the ice because the melted fresh water is quickly replaced by warmer seawater. “This process of large-scale and widespread seawater intrusion will increase expectations of sea level rise in Antarctica,” Renaud added.

Ted Scambos, a glaciologist at the University of Colorado in Boulder, who was not involved in the study, called the research “astonishing and important.” He stressed that this newly identified process could accelerate the pace of ice loss in climate predictions.

James Smith, a marine geologist at the British Antarctic Survey, highlighted the need to investigate whether the flow of seawater under Thwaites is a recent phenomenon or an unknown but long-standing feature. “Either way, it's clearly an important process that needs to be incorporated into ice sheet models,” he said.

Noel Gormelin, professor of Earth observation at the University of Edinburgh, praised the use of radar data in this study. “Ironically, by going into space, using our growing space capabilities, we learn a lot about this environment,” he said.

Despite the new discoveries, there are still many unknowns about what they mean for the future of thwaites and to what extent this process may occur in other parts of Antarctica.

Antarctica, an isolated and complex continent, is increasingly vulnerable to the climate crisis. A recent study by the British Antarctic Survey analyzed the record levels of low sea ice that surrounded Antarctica last year, concluding that such events would be “extremely unlikely” without the impact of climate change.

Although melting sea ice does not directly affect sea level rise, it exposes coastal ice sheets and glaciers to warm ocean waters, making them more vulnerable to melting.

Research suggests that Antarctica may face “permanent regime change”, with profound implications for local and global climate.