Underwater Eddies Accelerate Melting of Antarctic Glaciers, Study Finds

Recent research has identified that swirling underwater eddies, known as submesoscales, are intensifying the melting of Antarctic ice shelves, particularly beneath the Thwaites and Pine Island glaciers. These eddies, which can span up to six miles, form when warm and cold ocean waters meet, creating fast-changing, swirling currents. As these eddies move beneath the ice shelves, they churn up warmer water from deeper ocean layers, enhancing the melting process when this warmer water contacts the ice.

The study, published in Nature Geosciences, is the first to systematically analyze ocean-induced ice shelf melting over short timescales of hours and days, rather than seasons or years. The researchers utilized computer models and real-world data from ocean instruments to assess the impact of these underwater storms. They found that, along with other short-lived processes, the eddies accounted for 20% of the melting observed at the two glaciers over a nine-month period.

A concerning feedback loop was also highlighted: as the eddies melt the ice, they increase the amount of cold, fresh water entering the ocean. This influx mixes with warmer, saltier water beneath, generating more ocean turbulence, which in turn accelerates ice melting. This positive feedback loop could intensify in a warming climate.

The implications are significant, as ice shelves play a crucial role in holding back glaciers, slowing their flow into the ocean. Thwaites Glacier alone contains enough water to raise global sea levels by more than two feet. Its collapse could ultimately lead to approximately ten feet of sea-level rise.

The study underscores the importance of understanding fine-scale ocean phenomena in the context of ice loss and sea-level rise. However, the researchers acknowledge that more data is needed to comprehend how these underwater storms may vary over different seasons and years.