Ravindra Duddu, associate professor of civil and environmental engineering at Vanderbilt University, is among a team of researchers who have developed a novel approach to better predict fracture propagation in Greenland glaciers, which has implications for global sea level rise that impacts coastal communities around the world.
The research, led by Duddu, was published in the journal The Cryosphere in a paper titled, “Ice viscosity governs hydraulic fracture that causes rapid drainage of supraglacial lakes.” The study was selected as an editor’s highlight. Duddu also recently presented this study at the American Geophysical Union 2024 Fall Meeting.
A major concern of scientists is the melting and fracturing of the Greenland Ice Sheet (GrIS) due to continued Arctic warming. The GrIS is currently the largest contributor to global sea level rise. As the ice sheet’s surface melts, water can collect in streams and rivers as it moves over the ice surface, leading to the formation of supraglacial lakes. Drainage of these lakes could increase the speed of the entire ice sheet going into the ocean because of lubrication at the base, called basal sliding. As the ice sheet loses mass into the ocean, it can lead to a gradual rise in sea level over decades-to-centuries time scales.
As Duddu explained, existing ice sheet models do not appropriately account for surface water seeping through fractures and reaching the base of the ice sheet, lubricating it like oil, and causing it to slide.
“If we do not account for all the mechanisms properly by which ice can be transported from the land to the sea, then we may under predict the sea level rise,” Duddu said. “And that means in 50, 60, 70 years as sea level gradually rises, we may have a lot more coastal communities at enhanced risk.”
He said a key finding of the research is that ice viscosity, the measure of how resistant ice is to flow or the rate of deformation under stress, can control fracturing and whether a lake drainage event will occur, whereas previous studies assumed only ice elasticity, the measure of how resistant ice is to deformation under stress.
Co-author Jessica Mejia, who is an assistant professor of cryosphere and polar sciences in the Department of Earth and Environmental Sciences at Syracuse University, said as the climate continues to warm, melting on the surface of the Greenland Ice Sheet is expected to increase resulting in more supraglacial lakes forming at higher elevations.
“This modeling work provides a pathway to accurately model the rapid drainage of these lakes at higher elevations and estimate the consequences to ice flow speeds and ice sheet contributions to sea level rise, which are currently unknown,” she said.
Duddu initiated this research with Emilio Martínez Pañeda, associate professor at University of Oxford, supported by NSF CAREER and The Royal Society International Exchanges Schemes awards. Two early career researchers, Tim Hageman (now assistant professor at University of Oxford) and Mejía conducted the research study and are the lead authors on the paper.
Concurrently, Duddu is utilizing high-fidelity numerical models and machine learning to study iceberg calving from Antarctica ice shelves. He recently was awarded a grant from the Heising-Simons Foundation to develop a Neural Calving Ice-sheet Model (NeuCIM) to improve the projections of sea level rise using neural networks. In this effort, Duddu is collaborating with researchers at Georgia Institute of Technology and University of Chicago.
Contact: Lucas Johnson, lucas.l.johnson@vanderbilt.edu