Bold warning: hidden underwater storms may be rapidly eroding Antarctica’s ice from below, threatening faster sea-level rise than previously expected.
This piece originally appeared in Grist and examines new research suggesting that swirling, energetic water vortices beneath the West Antarctic Ice Sheet’s floating extension, the ice shelf, are driven by cycles of freezing and melting. When seawater freezes, it ejects salt; when it melts, it adds fresh water. These density changes create vertical, turbulent currents that pull relatively warm water up from the depths, potentially accelerating melting from below.
Lead author Mattia Poinelli, glaciologist at the University of California, Irvine, and affiliated with NASA’s Jet Propulsion Laboratory, describes the phenomenon as storm-like. The motions are vigorous and surface-ward, yet they originate beneath the ice shelf, where the once-stable insulating layer of cold water can be disrupted, exposing the ice to warmer currents. This undermines the protective boundary that would normally slow melting.
Researchers have also observed that instead of a flat, stable underbelly, the shelf can undulate, creating currents that expose more ice to warm water. Advanced autonomous instruments and robots are enabling this previously elusive view into the ice’s underside, offering new insights into how warm water intrudes and melts the ice from below.
Experts emphasize that the broader implications extend beyond the local shelf. The floating ice acts like a cork for the glacier perched on land; if the shelf’s underbelly melts and the shelf breaks up, the grounded ice may accelerate toward the ocean, pushing sea levels higher globally. In addition, the dramatic decline of sea ice around Antarctica reduces a natural buffer that absorbs wave energy and reflects sunlight. Less sea ice means more energy is absorbed by darker, unfrozen water, further warming the region.
As sea ice recedes and the shelf destabilizes, fresh water entering the ocean can fuel more storms that drive additional melting, creating a feedback loop. Poinelli notes that future warming could intensify these processes in other parts of Antarctica.
The new storm mechanism also helps explain recent observations of grounding line retreat, where ice loses contact with bedrock and starts floating. Freshwater outflows beneath the ice sheet can generate turbulence that draws up warm ocean water, hastening melting and destabilizing the entire ice system.
Separately, analyses of 25 years of data have shown grounding lines retreating as fast as 2,300 feet per year. When this retreat occurs, more of the glacier becomes exposed to warm water, accelerating ice loss.
While the current finding is model-based, there are corroborating observations in other regions of Antarctica. Scientists stress the need for more direct measurements to determine how much additional melting these underwater storms might cause and how quickly sea levels could respond.
Milillo emphasizes the urgency: Antarctica can change on timescales of days or weeks, not just decades or centuries. He argues that the underside of the ice shelf deserves the same monitoring attention as atmospheric weather systems, given its potential to reshape the continent’s contribution to sea-level rise.
Key takeaway: hidden underwater storms, driven by the interplay of freezing and melting, could be an important and rapid accelerator of Antarctic ice loss. The degree of impact remains uncertain, but the mechanism is now recognized as a plausible driver behind faster-than-expected ice retreat and ocean-level changes. Would you accompany the discussion with questions about how best to monitor these underwater processes or debate the extent of their influence on global sea-level rise?
