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Beneath the seemingly tranquil surface of Antarctica's Thwaites Glacier, scientists have discovered a dynamic and troubling phenomenon: underwater "storms" that significantly accelerate the glacier's melt. These vortexes of water swirl beneath the ice, contributing up to 20 percent of the glacier’s submarine melting during a typical season. Unlike the calm conditions observed above the ice sheets, the ocean below is anything but still. Small but powerful circulation patterns churn beneath the ice, causing rapid erosion and melting from underneath.
The Thwaites Glacier, often dubbed the "doomsday glacier," along with the nearby Pine Island Glacier, are critical to the stability of West Antarctica. Together, these two glaciers account for about one-third of the continent’s total ice loss. For decades, both glaciers have been thinning and retreating at an alarming rate, largely driven by the effects of climate change. Yet, understanding the exact mechanisms behind their retreat has been complex, involving a mix of atmospheric and oceanic processes. The recent study in Nature Geosciences sheds new light by pinpointing the role of underwater submesoscale features—tiny ocean currents and eddies only a few hundred meters wide—that act like mini-storms underneath the ice shelves.
This research, conducted by teams from UC Irvine and NASA’s Jet Propulsion Laboratory, zoomed in on ocean behavior near Antarctica on a timescale of days rather than months or years. By focusing on spatial scales as small as 200 meters, they identified submesoscale ocean features that seem to behave much like underwater hurricanes. These features push warmer waters into cavities beneath the ice shelves, accelerating melting from below. Lead author Mattia Poinelli likened these submesoscale circulations to storms threatening coastal areas, but in this case, the storm's fury is hidden beneath the Antarctic ice.
Though these underwater "storms" may be tiny in scale, their impact is substantial. Warm water intrudes into cracks and crevices in the glacier base, melting ice as it rises. This meltwater then interacts with the surrounding ocean, destabilizing the water column and fostering conditions for more submesoscale activity. The study highlights that the Thwaites Glacier region is particularly vulnerable due to its relatively shallow seabed topography, which intensifies these submesoscale currents, making it a hot spot for aggressive melting.
These findings carry important implications for climate modeling and sea level rise predictions. Until now, this driver of submarine melting had been largely unaccounted for, meaning existing models may underestimate how quickly Antarctic glaciers could disintegrate. Currently, Thwaites Glacier is losing roughly 50 billion tons of ice per year, contributing about 4 percent to global sea level rise. A full collapse of this glacier could raise sea levels by as much as 65 centimeters, potentially displacing hundreds of millions of people worldwide and causing trillions of dollars in damages.
In summary, the discovery of these submesoscale underwater storms provides a crucial piece of the puzzle in understanding Antarctic ice loss. As the climate continues to warm, the intensification of these processes may drive faster glacier retreat, escalating the risks associated with rising seas. Researchers emphasize that incorporating these dynamics into future climate models is vital to improve the accuracy of sea level rise projections and guide global response efforts.
