As the Aral Sea has been drained by irrigation and dried up, the mass loss on the surface has caused Earth’s upper mantle to rise up, lifting the emptied sea bed an average of 7 millimetres per year
By James Dinneen
7 April 2025
A ship graveyard in the Aral Sea desert, Uzbekistan
S@OwwL / Alamy
Unsustainable irrigation and drought have emptied nearly all of the Aral Sea’s water since the 1960s, causing changes extending all the way down to Earth’s upper mantle, the layer beneath the planet’s crust. This is probably the deepest recorded example of human activity changing the solid inner Earth.
“To do something that would affect the [upper mantle] is like, whoa,” says Sylvain Barbot at the University of Southern California. “It’s showing you how potent we are at changing the environment.”
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The Aral Sea in central Asia was once one of the world’s largest bodies of water, covering almost 70,000 square kilometres. But Soviet irrigation programmes starting in the 1960s, as well as later droughts, emptied the sea. By 2018, it had shrunk by almost 90 per cent and lost around 1000 cubic kilometres of water.
Wang Teng at Peking University in China became curious about the Aral Sea after reading a book about the consequences of this environmental disaster on Earth’s surface. “I realised that such a huge mass change would stimulate the response of the deep Earth,” he says.
He and his colleagues, including Barbot, used satellite measurements to track subtle changes in the emptied sea’s elevation between 2016 and 2020. Although much of the sea’s water disappeared decades ago, they found the uplift is ongoing, with the surface rising by around 7 millimetres per year on average.