A once-stable Greenland glacier is now rapidly melting

20 Apr. (EUROPE PRESS) –

As climate change causes ocean temperatures to rise, one of Greenland’s once most stable glaciers it is now retiring at an unprecedented rate.

Led by researchers at Ohio State University, a team found that between 2018 and 2021, the Steenstrup Glacier in Greenland has retreated about 8 kilometers, has thinned by 20%, has doubled the amount of ice it discharges into the ocean, and has quadrupled its speed. Such rapid change is so extraordinary among Greenland’s ice formations that it now places Steenstrup in the top 10% of glaciers that they contribute to the total ice discharge of the entire region.

The study is published in Nature Communications.

The Steenstrup Glacier is part of the Greenland Ice Sheet, a body of ice that covers nearly 80 percent of the world’s largest island, which is also the largest single contributor to global sea rise from the cryosphere, the portion of the Earth’s ecosystem that includes all of its frozen water. Although the region plays a crucial role in the balance of the global climate system, the area is constantly shrinking as it sheds hundreds of billions of tons of ice each year due to global warming.

In recent decades, much of this loss has been attributed to the accelerated discharge of ice from tidal glaciers, the glaciers that come into contact with the ocean. Many glaciologists believe that this recent increase in ice discharge can be explained by the intrusion of warm water being swept from the Atlantic into the Greenland fjords, critical ocean gateways that can affect the stability of local glaciers and the health of polar ecosystems.

The research team aimed to test that theory by examining a glacier in the southeastern region of Greenland called KIV Steenstrups Nordre Brae, an entity better known colloquially as the Steenstrup Glacier.

“Until 2016, there was nothing to suggest that Steenstrup was interesting in any way,” said it’s a statement Thomas Chudley, lead author of the study, who completed this work as a research associate at the Byrd Polar and Climate Research Center. Chudley is now a Leverhulme Fellow at Durham University in the UK.

“There were many other glaciers in Greenland that had retreated dramatically since the 1990s and increased their contribution to sea level rise, but this really wasn’t one of them.”

As far as scientists knew, Steenstrup had not only been stable for decades, but was generally impervious to the rising temperatures that had destabilized so many other regional glaciers, likely due to its isolated position in shallow water.

It wasn’t until Chudley and his colleagues compiled observational data and models from previous remote-sensing analyzes on the glacier that the team realized that Steenstrup likely it was melting due to anomalies in deeper Atlantic waters.

“Our current working hypothesis is that ocean temperatures have forced this retreat,” Chudley said. “The fact that the speed of the glacier has quadrupled in just a few years opens up new questions about how quickly large ice masses can actually respond to climate change.”

In recent years, glaciologists have been able to use satellite data to estimate the potential volume of glacial ice stored at the poles and how it might affect current sea levels. For example, if the Greenland ice sheet melted, Earth’s sea level could rise by almost 25 feet. In contrast, if the ice sheet in Antarctica were to crumble, it is possible that the oceans rise almost 60 meters, Chudley said.

While Greenland and Antarctica would take centuries to fully collapse, the global cryosphere has the potential to cause sea levels to rise by about six feet this century if the West Antarctic ice sheet suffers a collapse.

With about 10% of the planet’s population living in low-lying coastal areas, Chudley said any significant rise in sea levels can increase the risk of storm surge and tropical cyclones for low-lying islands and coastal communities.

Overall, Steenstrup’s unique behavior reveals that even long-term stable glaciers are susceptible to sudden retreat and fast as warmer waters begin to intrude and influence new environments.