As the climate warms, crevasses on the Greenland Ice Sheet are widening more rapidly, which is expected to accelerate ice loss and contribute to rising sea levels, according to a new study published in early February.
The study's findings, conducted by Durham University in partnership with Dr. Michalea King from the University of Washington and Dr. Emma MacKie from the University of Florida, were published in the peer-reviewed journal Nature Geoscience.
Crevasses are wedge-shaped fractures and cracks in the surface of glaciers formed by extensive stress within the ice. Water from melting snow on the surface can flow through crevasses to the bottom of the ice, where it joins other streams to create an extensive drainage system that enhances the flow of glaciers and ice sheets.
There has been a lot of uncertainty regarding processes controlling mass loss in surface crevassing on the Greenland Ice Sheet due to a lack of comprehensive observations of their location and evolution over time.
Study lead author Dr. Tom Chudley, a Leverhulme Early Career Fellow in the Department of Geography, Durham University, UK, said, "In a warming world, we would expect to see more crevasses forming. This is because glaciers are accelerating in response to warmer ocean temperatures, and because meltwater filling crevasses can force fractures deeper into the ice.
However, until now, we haven't had the data to show where and how fast this is happening across the entirety of the Greenland Ice Sheet.
Significant increases in the size and depth
For the first time, we are able to see significant increases in the size and depth of crevasses at fast-flowing glaciers at the edges of the Greenland Ice Sheet, on timescales of five years and less.”
The researchers used high-resolution 3D digital elevation models that mapped the volume of crevasse fields across the Greenland Ice Sheet in 2016 and 2021. The model displayed that between these years, there were significant increases in crevasse size and depth at the ice sheet’s edges, which could further speed up the mechanisms causing the loss of ice in Greenland.
The study also found that approximately 50 to 90 percent of the water flowing through the Greenland Ice Sheet passes through crevasses.
“As crevasses grow, they feed the mechanisms that make the ice sheet’s glaciers move faster, driving water and heat to the interior of the ice sheet and accelerating the calving of icebergs into the ocean,” said study co-author Ian Howat, director of the Byrd Polar and Climate Research Center and professor at Ohio State.
“These processes can, in turn, speed up ice flow and lead to the formation of more and deeper crevasses – a domino effect that could drive the loss of ice from Greenland at a faster pace.”
The study highlights the significance of considering the role of crevassing in future predictions about ice-sheet behavior and the anticipated impacts of climate change on the world’s polar regions.
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