Researchers from the University of California, Irvine and NASA’s Jet Propulsion Laboratory have discovered that storm-like circulation patterns beneath Antarctic ice shelves are causing aggressive melting, which has serious implications for global sea-level rise projections. In the study, published in Nature Geoscience, scientists for the first time examined ocean-driven glacier melt events on timescales of days rather than seasons or years. This allowed them to link the activity of “ocean storms” to intense melting of the Thwaites and Pine Island glaciers in the Amundsen Sea in West Antarctica. The team used climate modeling and observational data to obtain a picture of sub-mesoscale ocean features ranging in size from 1 to 10 kilometers. How Sub-ice “Storms” Cause Melting “Just as hurricanes and other large storms threaten vulnerable coastal regions around the world, sub-mesoscale features in the open ocean propagate toward ice shelves and cause substantial damage,” explained lead author Mattia Pennelli. “Sub-mesoscale events cause warm water to penetrate into the cavities beneath the ice, melting them from below. These processes occur year-round in the Amundsen Sea and are a key driver of submarine melt.” The researchers identified a positive feedback loop: greater glacier melt generates more ocean turbulence, which in turn causes even more melting. Implications and Future Risks The study found that these short-lived, high-frequency processes account for nearly one-fifth of the total submarine melt variability over a full seasonal cycle. During extreme events, submarine melting can triple within hours. “The area between the Crosson and Thwaites ice shelves is a hotspot for sub-mesoscale activity,” noted Pennelli. “The floating tongue of the Thwaites Glacier and the shallow seafloor act as a topographic barrier, amplifying this activity, making the area particularly vulnerable.” The study’s findings are particularly relevant in light of climate change. If the West Antarctic Ice Sheet collapses, global sea levels could rise by up to 3 meters. Significance for the Future “These results demonstrate that small-scale ocean features are among the main drivers of ice loss,” stated Pennelli. “This underscores the need to incorporate these short-term, ‘weather-like’ processes into climate models for more complete and accurate sea-level rise projections.” Eric Rignot, a professor of Earth system science at UC Irvine, commented, “This research highlights the urgent need for funding and developing better observation tools, including advanced ocean robots capable of measuring these sub-ice processes.”
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