A new study reveals violent underwater vortices beneath Antarctica's ice shelves that draw warm water to the surface, accelerating ice melt. These 'storms' are driven by the freezing and melting of sea ice, displacing protective cold water layers. The findings highlight rapid changes in the West Antarctic Ice Sheet, threatening global sea levels.
The West Antarctic Ice Sheet spans 760,000 square miles and reaches thicknesses of up to 1.2 miles. Its complete melting could raise global sea levels by 10 feet, a process expected over centuries amid human-induced warming. However, recent research indicates faster perils, including abrupt sea ice losses that compound the issues.
A paper published in Nature Geoscience identifies chaotic underwater 'storms' as a new factor in the ice's deterioration. These vortices form when sea ice freezes, ejecting salt, or melts, adding fresh water—both altering ocean density and pulling warm deep water toward the ice shelf's underside. "They look exactly like a storm," explained lead author Mattia Poinelli, a glaciologist at the University of California, Irvine, and NASA Jet Propulsion Laboratory affiliate. "They’re strongly energetic, so there is a very vertical and turbulent motion that happens near the surface."
This turbulence disrupts the insulating frigid water layer at the ice-ocean interface, exposing the shelf to warmer currents. The ice shelf functions like a cork, buttressing the inland glacier; its erosion could hasten the sheet's flow into the ocean. Declining sea ice exacerbates this by removing a buffer against waves and reducing solar reflection, leading to warmer seas and more freshwater influx that fuels additional storms.
"In the future, where there is going to be more warm water, more melting, we’re going to probably see more of these effects in different areas of Antarctica," Poinelli noted. These dynamics may also drive grounding line retreats, where ice transitions from land to sea—recent data shows retreats up to 2,300 feet annually, allowing broader warm water access.
"This study provides a compelling mechanism of tiny but powerful storms that punch beneath the ice and accelerate melt," commented Pietro Milillo, a University of Houston physicist. Though based on modeling, similar processes have been observed elsewhere in Antarctica. Clare Eayrs, a climate scientist at the Korea Polar Research Institute, emphasized the need to understand warm water intrusion: "We’re really trying to understand, Where is warm water getting in, how’s it getting in, and what are these processes by which the ice is melting from below?"
Milillo warned that Antarctic changes can occur in days or weeks, urging urgent monitoring of ice undersides akin to atmospheric storm tracking. More data is essential to quantify melting rates and sea level impacts.