Scientists Find Hidden 'Plumbing' in Antarctica That's Causing Ice To Melt Faster Than We Expected

It is normal for glaciers to flow and break off into icebergs. But the rate at which ice is collapsing in Antarctica is way too much to escape notice. Every second day, swathes of Antarctic ice appear to be calving into jumbo icebergs that start melting as the mercury rises on the scale. Their signature “detonation sound” is followed by a gush of meltwater that instantly poses the threat of sea level rise. NASA says the melting of Antarctica's ice sheet is currently responsible for 20 to 25% of the global sea level rise.

Take the case of the Brunt Ice Shelf. Icebergs hundreds of miles wide calved off from the shelf in the spring tide in January 2023, followed by another break-off in the summer of 2024. Thwaites Glacier is already showing cracks, whereas the Wilkins ice shelf is repeatedly displaying signs of collapse. In a research published in the journal Geophysical Research Letters, scientists recently revealed how the culprit behind this unusually rapid calving could be Antarctica’s “hidden plumbing,” a.k.a. “subglacial hydrology.”

Subglacial hydrology, the researchers explain, “describes the complex routing by which meltwater at the glacier bed flows along the ice-bedrock interface until it reaches the grounding line (GL) where the glacier transitions from sliding across the bedrock to floating in the ocean.” They explained that the presence of liquid water within the ice geometry alters the basal friction exerted on the glacier by the underlying bedrock and, therefore, the flow speed of the overlying ice, making it a crucial component of glacier physics. They further said that the timing and magnitude of Antarctic mass loss are determined by this subglacial hydrology, which in turn largely impacts the “sea level projections.”

The research authors estimated that the ice melt from Antarctica could raise the sea levels up to 12 inches by the year 2100. And since Antarctica is the largest body of ice on the planet, it could become a major trigger, raising the global sea levels to an alarming scale. Some of this melting happens when geothermal heat melts the bedrock of ice and frictional heat that lubricates the ice while flowing over the bed.

Another reason could be the “release of water from subglacial lakes,” the researchers explained in the paper. They emphasized that although the plumbing is not generally incorporated in ice dynamics models, the connection between the two cannot be denied. This is the first study to throw light on this connection. “Although these in situ volumes of water are generally small, the large catchments of Antarctica mean that vast networks of connected cavities and long channels can develop at the base and direct this water to the ocean. The areas where water accumulates at high pressure are the fastest regions of ice flow in the Antarctic, suggesting a direct link between subglacial hydrology and Antarctic ice flow dynamics,” they wrote.

Subglacial discharge, they said, is the main driver of sea level rise. “Surrounding the Antarctic Ice Sheet are ice shelves, floating bodies of ice which provide backstress, limiting the flow speed of grounded ice into the ocean. Melting of these ice shelves, particularly at the GL, can lead to increased ice discharge, ultimately raising sea levels,” reads the paper. To determine how quickly Antarctica’s glaciers would retreat into the oceans, causing sea levels to rise, scientists employed a set of computer models.

One model, the “Glacier Drainage System Model,” was designed to simulate water flow under ice sheets. The other model, the “Ice-sheet and Sea-level System Model,” was supposed to predict the ice flow based on factors like temperature. In conclusion, the team said that the models revealed that the lowest effective pressures are in the “interior of the continent” and “below the fast-flowing ice streams.” They noted that the “largest effective pressure values occur throughout the Peninsula and along the margins of the ice sheet.”