As climate change causes ocean temperatures to rise, one of Greenland’s once most stable glaciers is now retreating at an unprecedented rate.
Led by Ohio State University researchers, a team found that between 2018 and 2021, the Steenstrup Glacier in Greenland has retreated about 8 kilometers, thinned 20%, doubled the amount of ice it discharges into the ocean, and It 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 contributing to total ice discharge from the entire region, the study said.
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. While the region plays a crucial role in balancing the global climate system, the area is steadily 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 may be explained by the intrusion of warm waters being swept from the Atlantic into the Greenland fjords, critical oceanic gateways that may affect local glacier stability and 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,” Thomas Chudley, the study’s lead author, who completed this work as a research associate at the Byrd Polar and Climate Research Center, said in a statement. 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 was likely 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 glacier’s speed 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. By contrast, if the ice sheet in Antarctica were to crumble, the oceans could rise nearly 200 feet, Chudley said.
While it would take Greenland and Antarctica centuries to fully collapse, the global cryosphere has the potential to cause sea levels to rise about six feet this century if the West Antarctic ice sheet collapses.
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 and rapid retreat as warmer waters begin to intrude and influence new environments.
