The Greenland Ice Sheet, the world’s second-largest body of ice, is cracking open more quickly than previously thought, with significant implications for global sea levels. A new large-scale study conducted by researchers from Durham University and published in the journal Nature Geoscience highlights the alarming rate at which crevasses are widening and deepening at the ice sheet's fast-flowing edges.
Using over 8,000 three-dimensional surface maps created from high-resolution satellite imagery, the scientists tracked the changes between 2016 and 2021. What they found was concerning: crevasses—wedge-shaped fractures where the ice begins to flow faster—grew significantly larger and more extensive during this period. Dr. Tom Chudley, the lead author of the study, stated, "Understanding crevasses is key to how this discharge will evolve in the 21st century and beyond." This is particularly troubling as these cracks allow water from melting snow at the surface to flow down to the base of the ice, effectively lubricacing it and potentially hastening the flow of the ice itself.
Crevasses form predominantly where large glaciers meet the sea, and the researchers noted accelerations in glacier flow speed were linked to significant increases in the volume of crevasses—up to 25 percent larger in some areas. This phenomenon is configured as part of broader climate change impacts, as the increasing temperatures thaw ice and cause glaciers to flow more rapidly.
Dr. Chudley elaborated, “With this dataset, we can see significant increases not just in the numbers of crevasses, but more worryingly, existing crevasse fields are getting larger and more deeply rooted.” This directly correlates to the rate of iceberg discharge and the overall melting of the Greenland Ice Sheet, which researchers previously estimated contributes approximately 14 millimeters to global sea level rise since 1992. If the entire ice sheet were to melt, it could raise sea levels by up to seven meters (approximately 23 feet).
The study’s findings accentuate the importance of reassessing models used for climate predictions. William Colgan, from the Geological Survey of Denmark and Greenland, remarked, "With the appearance of crevasses, there are many feedback loops to increase ice loss. Crevasses are set to play a large role in the ice sheet’s response to climate change, potentially exceeding current forecasts." This makes it increasingly urgent to understand how such structural changes can influence future sea level rise.
Climate researchers have already observed accelerating melting rates, with Greenland's ice contributing about one meter (approximately three feet) to sea level rise by the year 2100. But the situation isn't static, with some glaciers like the Sermeq Kujalleq historically experiencing oscillations between fast and slow flow states. Such fluctuations complicate the broader picture of how the ice sheet behaves as warmer temperatures push the limits of how glaciers can hold their form.
Professor Ian Howat from Ohio State University conveyed the accelerating nature of the phenomenon, saying, "These processes, as crevasses grow, feed the mechanisms driving glaciers to move faster—this is likely to create more and even larger crevasses." The reiterative feedback of accelerated flow and deepening cracks contributes to the concern surrounding the future stability of the Greenland Ice Sheet.
The Arctic is warming at rates higher than any other region on Earth, with changes to its glacial structures expected to redefine our current understandings of climate science. Therefore, the comprehensive mapping and research conducted through studies such as this one from Durham University serve as pivotal areas of focus for scientists tasked with predicting how changes impact not just regional ecosystems, but the global environment.
The urgency of this research cannot be overstated; the melting of the Greenland Ice Sheet is not merely an environmental issue but one of global significance, threatening the livelihoods of millions worldwide. The findings from this study should resonate with policymakers and climate activists alike, underscoring the immediate need for actions to mitigate climate change.
This mapping of crevasses heralds the beginning of more sophisticated predictions about the future of the Greenland Ice Sheet, which is pivotal to global sea levels. Continued monitoring through projects like ArcticDEM promises to furnish researchers with high-resolution data necessary for staying abreast of climatic changes as they manifest.
By offering the most comprehensive look at the evolution of Greenland's crevasses to date, the researchers hope to empower future studies and improve models predicting future sea level rise as the world responds to climate change. The backdrop of rising temperatures renders the knowing of how ice masses shift from solid to liquid states ever more imperative, with the fate of immense coastlines hanging precariously on the fulfillment of such knowledge.