Secret lakes of Antarctica could reshape the future of sea level

Scientists using ESA Cryosat satellite have discovered 85 new sub-group lakes in Antarctica, showing how water networks hidden under the movement of glaciers with ice driving and affect the elevation of sea level.

Hundreds of sub-Glacial lakes are deep under the hundreds of sub-Glacial lakes of Antarctica which play an essential role in the formation of the frozen landscape of the continent. These underground tanks influence the movement and flow of glaciers, which in turn affects the world’s sea level.

Relying on ten years of observations of the European Space AgencyCryosat satellite, scientists discovered 85 lakes previously previously located several kilometers under the ice near the South Pole. With this discovery, the number of active sub-glacial lakes documented in Antarctic has increased by more than half, reaching 231 in total.

Rare information on the dynamics of antarctic ice cream

The study, published on September 19 Nature communicationsis particularly important because these active lakes flow periodically and recharging, offering a rare window on processes occurring well below the surface at the base of the ice cap. Researchers have also identified new underground drainage pathways, including five interconnected lakes.

The main author Sally Wilson, a doctoral researcher at the University of Leeds, stressed how much he is currently understood about these hidden waters. The challenge, she explained, is that they are buried under hundreds of meters of ice.

“It is incredibly difficult to observe the filling and drainage events of the sub-Glacial lake under these conditions, especially since they take several months or years to fill and drain. Only 36 complete cycles, from the start of the sub-Glacial filling until the end of drainage, had been observed in the world before our study. We observed 12 more complete filling events, bringing the total to 48 years. ”

Why satellites count

This is where the satellites were able to provide precious data to research. The observations of the Cryosat mission, which were launched in 2010, were able to produce a set of data extending from 2010 to 2020.

ESA’s Cryosat satellite, which is part of the ESA Futureeo program, measures the thickness of polar ice and monitors changes in the height of ice caps on Greenland and Antarctica and glaciers in the world. Its main instrument is an radar altimeter, which can detect tiny variations in the surface of the ice and measure the height of the sea surface.

Using a decade of cryosat observations, the researchers detected changes located in the height of the icy surface of the Antarctic, which rises and falls when the lakes fill and flow at the base of the ice cap. They could then detect and map the sub-glacial lakes and monitor their filling and drainage cycles over time.

Anna Hogg, co-author of the study and professor at the University of Leeds, said: “It was fascinating to discover that the areas of the sub-Glacial lakes can change during various filling or drainage cycles.

A vital piece for sea level predictions

Sally explained that observations like these are essential to understand the structural dynamics of glacial caps and how they affect the ocean that surrounds them. “The digital models that we are currently using to project the contribution of whole ice cream caps to the elevation of sea level do not include sub-Glacial hydrology. These new sets of data from locations, extended time and time changes will be used to develop our understanding of processes that cause water flow under Antarctic. ”

Martin Portant, coordinator of Cluster Science Polar Science, noted: “This research again demonstrates the importance of the Cryosat mission data to improve our understanding of polar regions and in particular the dynamics of glacial caps. The more we understand on the complex processes affecting the glacial cap of the Antarctic, including the flow of fusion at the base of the ice sheet, the more we can project on the progress of the future. “

How is a sub-Glacial lake formed?

Sub-glacial fusion waters are formed due to the geothermal heat of the ground surface of the earth and the friction heat as the ice slides on the rocky substratum. This melting water can pool on the surface of the rocky substratum and flows periodically. This water flow has the potential to reduce the friction between ice and the rocky substratum on which it is located, allowing the ice to slide more quickly into the ocean.

Not all sub -glacial lakes are considered active – many are considered stable because they are not known to fill or flow. The largest known sub-Glacial lake is Lake Vostok under the ice cap of the Eastern Antarctic, containing approximately 5,000 to 65,000 cubic kilometers of water under 4 km of ice (the water contained in Lake Vostok is sufficient to fill the large canyon and the overflow of at least 25%). Although Lake Vostok is considered stable, if it flowed, it would have an impact on the stability of the Antarctic Glacial Cut, surrounded ocean circulation, sea habitats and world level.

Implications for climate modeling

The filling and drainage cycles of sub-glacial lakes are an important set of data for ice and climate models. By monitoring such phenomena, scientists can improve their understanding of interactions between the glacial cap, the foundation, the ocean and the atmosphere, which is essential for understanding the future stability of the glacial caps.

“Sub-Glacial hydrology is a missing piece in many models of ice cap,” said Sally. “By mapping where and when these lakes are active, we can start quantifying their impact on ice dynamics and improving the projections of the future increase in sea level.”

Reference: “Detection of 85 new active sub-glacial lakes in Antarctica from a decade of Cryosat-2 data” by Sally F. Wilson, Anna E. Hogg, Richard Rigby, Noel Gourmelen, Isabel Nias and Thomas Slater, September 19, 2025, Nature communications.
Two: 10.1038 / S41467-025-63773-9

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