Underwater “storms” are quietly gnawing away at the Doomsday Glacier and its nearby neighbor, threatening substantial effects on sea level around the globe. A new study highlights that these ocean-driven processes could have far-reaching consequences far sooner than previously thought, reshaping our understanding of how quickly ice shelves can melt.
Antarctica resembles a clenched fist with a slender thumb extending toward South America. Pine Island Glacier sits near the base of that thumb, while the Doomsday Glacier, Thwaites, lies just beside it. Both have faced accelerated melting in recent decades, driven largely by warmer ocean waters that buffet the ice shelves where they rise from the seabed and float on the sea.
Published last month in Nature Geoscience, the study marks the first comprehensive effort to quantify how the ocean can melt ice shelves on timescales of hours to days, rather than the more common long, seasonal or yearly frames. Researchers describe this as a shift from studying “weather” in the atmosphere to watching fast-changing ocean features that directly temper Antarctic ice.
The focus is on submesoscale underwater eddies—dynamic, swirling pockets of water that form when warm and cold waters interact. Think of them as vigorous water spirals—large enough to span several miles—that churn beneath ice shelves. Dr. Yoshihiro Nakayama of Dartmouth College explains that these phenomena operate on very short timescales, unlike the slower, more familiar climate trends we often study.
The best way to picture these eddies is to compare them to the way milk swirls into a cup of coffee: distinct, rapidly shifting patterns that nevertheless mix the contents. In the Southern Ocean, these eddies arise where opposing water masses meet and, as they move under the ice shelf, they pull warmer water up toward the base. That heat reaches vulnerable ice and accelerates melting where the shelf is in contact with the deeper ocean.
To assess their impact, the team combined computer modeling with actual measurements from ocean instruments. Their analysis showed that, alongside other short-lived processes, these underwater storms contributed about 20% of the ice loss at Pine Island and Thwaites over a nine‑month window. While disentangling the precise share of melting caused solely by storms is challenging due to the chaotic nature of these flows, the results point to a meaningful role for such events on short timescales.
A worrying feedback loop also emerges. As the eddies melt ice, they inject more freshwater into the ocean, which cools the surrounding water and helps stratify it. This freshening interacts with the warmer, saltier water below to create more turbulence, which can drive still more melting. Researchers caution that this loop could intensify as the climate warms.
The stakes are high because ice shelves act as brakes on glacier flow, slowing the movement of ice into the ocean. Thwaites alone contains enough water to raise global sea levels by roughly two feet if it were to collapse, and its loss would also remove a crucial buttress holding back the larger Antarctic ice sheet, potentially allowing far more ice to reach the sea and contributing to about ten feet of sea level rise in total.
Experts not involved in the study applaud its focus on the often-overlooked small-scale ocean features that can erode the base of ice shelves. The reported extent of melting is striking, according to independent researchers, underscoring how even tiny-scale processes can have major impacts on the ice.
However, uncertainties abound. Antarctic ice shelves are among the planet’s most inaccessible regions, so scientists rely heavily on computer models to simulate conditions. While these results are compelling, additional real-world data is needed to confirm how such eddies behave across different seasons and years and to understand their interactions with other oceanic weather patterns.’’
Despite the gaps, the study emphasizes that these short-lived, weather-like ocean processes are far from negligible. They represent the next frontier in deciphering ocean–ice dynamics that influence ice loss and, ultimately, sea level rise. As researchers push to gather more observations, the broader picture of how near-ice ocean conditions affect the stability of Antarctica’s ice shelves will become clearer—and potentially more urgent.
