Hidden lakes beneath Antarctic ice can trigger rapid, large-scale melting events

Beneath the Thwaites Glacier lies a network of subglacial lakes that can drain simultaneously, releasing massive volumes of freshwater into the ocean. This process disrupts local water temperatures and accelerates the thinning of ice shelves, threatening the stability of the entire Antarctic ice sheet.

In 2013, seven subglacial lakes located over 2 km beneath the Thwaites Glacier drained at once, discharging approximately 7 cubic kilometres of freshwater into the Amundsen Sea. Because this freshwater is less dense than the surrounding salty ocean, its release at a depth of roughly 1 km triggered a turbulent upwelling of warm, deep-sea water.

This mechanism directly impacts the ice shelf's buttressing effect—the ability of the shelf to hold back inland ice. By accelerating melting at the base of the ice shelf and creating a polynya, the drainage event caused the inland ice to flow more rapidly into the ocean. Research utilizing CryoSat data, published in Nature Communications, highlights how these complex subglacial dynamics influence the broader stability of the Antarctic ice sheet.

Source: How hidden lakes threaten Antarctic Ice Sheet stability