'1.1 billion tonnes of water...': How the Soviet-era Aral Sea disaster is still reshaping the Earth's mantle
The Aral Sea, once the world’s fourth-largest lake, is now not only a dried-out ecological ruin but the source of an extraordinary geological ripple.


- Apr 19, 2025,
- Updated Apr 19, 2025 9:10 PM IST
What began as a Soviet-era irrigation project in the 1960s has become a long shadow cast deep into the Earth’s interior. The Aral Sea, once the world’s fourth-largest lake, is now not only a dried-out ecological ruin but the source of an extraordinary geological ripple. A new study in Nature Geoscience reveals that the weight loss from its near-disappearance triggered a rebound in Earth’s crust and mantle — an upheaval that is still unfolding nearly 80 years later.
Nicknamed the “quiet Chernobyl” for its long-term ecological damage, the Aral Sea’s retreat has long symbolised environmental collapse, but scientists now see it as a rare geophysical case study. Over eight decades, the lake lost more than 1.1 billion tonnes of water — roughly the mass of 150 Great Pyramids of Giza. That loss didn't just leave behind a desert; it set in motion a subterranean shift.
As the surface sheds the load, Earth’s crust is gradually springing back. “Because the weight of the water in the lake would have depressed the underlying rock,” wrote geologist Simon Lamb, “it was anticipated that this rock would rebound by some small fraction of the original water depth while the weight was being removed.”
What scientists didn’t expect was the extent — and persistence — of that rebound. It has spread far beyond the dried lakebed and penetrates deep below the crust, into the mantle itself. Using satellite radar (InSAR) data from 2016 to 2020, researchers traced a subtle but steady bulge extending 310 miles from the lake’s center.
The land is rising at 0.3 inches per year, with a total lift of 1.6 inches observed so far. Scientists believe this is due to mantle rocks slowly flowing in to fill the space once compressed by the Aral Sea’s weight.
“The Aral Sea, although never particularly deep, was wide enough in its heyday for its weight to be felt in the Earth at tens to hundreds of kilometres depth,” Lamb told Daliy Galaxy. “This is because the outermost strong layer of cold rock cannot carry the weight of such a wide body of water without sinking slightly into the underlying hotter and weaker rocks.”
What remains of the Aral Sea is a dust-blown basin, scattered with rusting ships and salt-crusted soil. Yet the real scars lie deep underground. What once seemed a regional calamity is now understood as a planetary signal — a reminder that human activity can reach down to the molten engine of the Earth.
The study warns that other large-scale environmental changes, like glacial retreat and groundwater depletion could similarly disturb Earth’s deep structure.
What began as a Soviet-era irrigation project in the 1960s has become a long shadow cast deep into the Earth’s interior. The Aral Sea, once the world’s fourth-largest lake, is now not only a dried-out ecological ruin but the source of an extraordinary geological ripple. A new study in Nature Geoscience reveals that the weight loss from its near-disappearance triggered a rebound in Earth’s crust and mantle — an upheaval that is still unfolding nearly 80 years later.
Nicknamed the “quiet Chernobyl” for its long-term ecological damage, the Aral Sea’s retreat has long symbolised environmental collapse, but scientists now see it as a rare geophysical case study. Over eight decades, the lake lost more than 1.1 billion tonnes of water — roughly the mass of 150 Great Pyramids of Giza. That loss didn't just leave behind a desert; it set in motion a subterranean shift.
As the surface sheds the load, Earth’s crust is gradually springing back. “Because the weight of the water in the lake would have depressed the underlying rock,” wrote geologist Simon Lamb, “it was anticipated that this rock would rebound by some small fraction of the original water depth while the weight was being removed.”
What scientists didn’t expect was the extent — and persistence — of that rebound. It has spread far beyond the dried lakebed and penetrates deep below the crust, into the mantle itself. Using satellite radar (InSAR) data from 2016 to 2020, researchers traced a subtle but steady bulge extending 310 miles from the lake’s center.
The land is rising at 0.3 inches per year, with a total lift of 1.6 inches observed so far. Scientists believe this is due to mantle rocks slowly flowing in to fill the space once compressed by the Aral Sea’s weight.
“The Aral Sea, although never particularly deep, was wide enough in its heyday for its weight to be felt in the Earth at tens to hundreds of kilometres depth,” Lamb told Daliy Galaxy. “This is because the outermost strong layer of cold rock cannot carry the weight of such a wide body of water without sinking slightly into the underlying hotter and weaker rocks.”
What remains of the Aral Sea is a dust-blown basin, scattered with rusting ships and salt-crusted soil. Yet the real scars lie deep underground. What once seemed a regional calamity is now understood as a planetary signal — a reminder that human activity can reach down to the molten engine of the Earth.
The study warns that other large-scale environmental changes, like glacial retreat and groundwater depletion could similarly disturb Earth’s deep structure.