Ocean Storms Under Antarctica Accelerate Ice Melt, Threatening Global Sea Levels
New research reveals previously overlooked, storm-like ocean currents are rapidly melting Antarctic ice shelves from below, with potentially devastating consequences for global sea level rise.
Researchers at the University of California, Irvine and NASA’s Jet Propulsion Laboratory have identified a critical and accelerating factor in Antarctic ice melt: submesoscale ocean features – essentially, “ocean storms” – circulating beneath ice shelves. Published recently in Nature Geoscience, the study marks the first to examine these melting events on a timescale
Warm water is being channeled into cavities beneath the ice, causing significant melting from below.
“In the same way hurricanes and other large storms threaten vulnerable coastal regions around the world, submesoscale features in the open ocean propagate toward ice shelves to cause ample damage,” explained a lead author of the study, a postdoctoral scholar in Earth system science. “Submesoscales cause warm water to intrude into cavities beneath the ice, melting them from below.The processes are ubiquitous year-round in the Amundsen Sea Embayment and represent a key contributor to submarine melting.”
The study uncovered a hazardous positive feedback loop: as ice shelves melt, they generate more ocean turbulence, which in turn accelerates further melting. “Submesoscale activity within the ice cavity serves both as a cause and a result of submarine melting,” the researcher elaborated. “The melting creates unstable meltwater fronts that intensify these stormlike ocean features, which then drive even more melting through upward vertical heat fluxes.”
These ephemeral, high-frequency processes account for nearly a fifth of the total submarine melt variance over an entire seasonal cycle. During extreme events, submarine melting can increase by as much as threefold within hours as these features collide with ice fronts and penetrate beneath the ice base. The findings are corroborated by high-resolution observational data from moorings and floats deployed in the Antarctic, confirming intermittent warming and increased salinity at depths consistent with the observed melting events.
The region between the Crosson and Thwaites ice shelves has been identified as a particular “hot spot” for this activity. The unique topography of the area – the floating tongue of the Thwaites ice shelf and the shallow seafloor – enhances submesoscale activity, making it exceptionally vulnerable.
The implications of this research are particularly urgent given the potential for catastrophic sea level rise. If the West Antarctic Ice Sheet were to collapse, global sea levels could rise by up to 3 meters. The study suggests that future scenarios with warmer waters, longer periods of open water (polynya), and reduced sea ice coverage will likely exacerbate these submesoscale fronts, further destabilizing ice shelves.
“These findings demonstrate that fine oceanic features at the submesoscale – despite being largely overlooked in the context of ice-ocean interactions – are among the primary drivers of ice loss,” the researcher stated. “This underscores the necessity to incorporate these short-term, ‘weatherlike’ processes into climate models for more thorough and accurate projections of sea level rise.”
A co-author, an assistant professor of engineering at Dartmouth, noted the meaning of the model’s accuracy. “initially, I was just trying to understand the observations using model output… But now that our model matches the data so well, we can go an extra step. We can extrapolate further to say there’s weatherlike storms hitting and melting the ice.”
Another expert, a professor of Earth system science at UC Irvine, emphasized the need for improved observation tools. “This study and its findings highlight the urgent need to fund and develop better observation tools, including advanced oceangoing robots that are capable of measuring suboceanic processes and associated dynamics.”
The research team included scientists from the Scripps Institution of Oceanography at the University of California, San Diego. Funding for the project was provided by NASA’s Cryospheric Sciences Program, with support from the NASA Advanced Supercomputing division. These findings represent a critical step forward in understanding the complex dynamics driving Antarctic ice melt and underscore the urgent need for more accurate climate modeling and continued investment in polar research.
