More cracks in the Greenland glacier may trigger a positive feedback loop that endangers its stability.
Over the course of just five years, approximately 930 million cubic meters of crevasses emerged in the Greenland ice sheet. This is akin to the formation of a crack as large as the Great Pyramid of Giza every few days on the world’s second-largest ice sheet.
The rise in crevasses, particularly in the swiftly moving sections of the ice sheet, might initiate a feedback loop that accelerates the glacier’s ice loss, ultimately contributing to rising sea levels. Since 1992, the melting of Greenland’s ice has added about 0.4 inches to global sea levels, with projections suggesting an increase of another foot by century’s end.
These insights stem from a new study conducted by researchers from the University of Florida, Durham University in the UK, and other institutions, examining Greenland from 2016 to 2021. This research marks the first extensive analysis of crevasses on the glacier over multiple years, enabling scientists to observe changes in crevasses over relatively short timeframes.
Studying the behavior of crevasses across the entire Greenland ice sheet necessitated innovative methods.
“Field studies are not feasible due to the dangerous nature of crevasses. It’s also challenging to analyze manually using satellite data. We need automated methods to assess this on an ice-sheet scale,” explained Emma MacKie, Ph.D., a geological sciences professor at the University of Florida, who co-authored the study and is skilled in machine learning techniques.
The research team, which included experts from Ohio State University and the University of Washington, created an automated system for detecting and measuring crevasses based on three-dimensional satellite images sourced from the Polar Geospatial Center.
While overall trends indicate a rise in crevasses across Greenland, different areas of the glacier exhibited varying behaviors. One region on the island’s west side actually experienced a decrease in crevasse volume during the study period. However, this decline was outweighed by significant increases, reaching up to 25%, in other parts of the glacier.
Since the completion of the study, the western region has started to form more cracks, likely leading to increased crevassing throughout the ice sheet in the years to come.
“Crevasses can accelerate ice flow, which leads to the formation of more crevasses. Thus, there are potential positive feedback loops linked to crevassing,” MacKie noted. “This process should be incorporated into the models used to forecast future sea level rise related to the Greenland ice sheet.”
This research received partial support from the National Aeronautics and Space Administration and the National Science Foundation.
