Steep increases in crevassing, particularly in swiftly flowing sectors, may trigger feedback loops that accelerate ice loss and drive sea level rise. Since 1992, Greenland's melt has lifted global sea levels by about 0.4 inches, with experts predicting it will add another foot by the end of this century.
Those conclusions emerge from a study examining Greenland between 2016 and 2021, undertaken by scientists from the University of Florida, Durham University in the United Kingdom, and other institutions. Their work is the first multi-year, ice-sheet-wide analysis of crevasses, enabling researchers to observe how these fractures evolve over relatively brief spans of time.
Investigating crevasse behavior across all of Greenland's ice demanded innovative methods.
"You can't do it in person, because crevasses are dangerous. It's hard to study by hand using satellite data. Automated approaches are needed to determine this at an ice-sheet scale," explained study co-author and University of Florida geological sciences professor, Emma MacKie, Ph.D., who specializes in machine learning methods.
Along with experts from Ohio State University and the University of Washington, the team devised an automated crevasse detection and measurement tool, drawing on three-dimensional satellite imagery provided by the Polar Geospatial Center.
Although the overall data reveal growing crevassing throughout most of Greenland, specific areas display contrasting trends. A western region actually experienced a dip in crevasse volume during the study period, but that decline was more than offset by sharp increases, as high as 25 percent, in other parts of the glacier.
After the study ended, the west side began forming additional cracks, indicating that larger swaths of the ice sheet will likely see an uptick in crevassing in the near future.
"Crevasses can induce accelerated ice flow, leading to more crevassing. So there are these potential positive feedback loops caused by crevassing," MacKie said. "This mechanism should be considered in Greenland ice sheet models that we're using to project future sea level rise."
Partial funding for this research was provided by the National Aeronautics and Space Administration and the National Science Foundation.
Research Report:Increased crevassing across accelerating Greenland Ice Sheet margins
Related Links
University of Florida
Beyond the Ice Age
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