The Drying Planet - Part Two

TITLE: The Drying Planet - Part Two

AUTHOR: Abraham Lustgarten, ProPublica

SOURCE: This story was originally published on July 25, 2025, by ProPublica.

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The Drying Planet - Part Two

The study examines 22 years of observational data from NASA’s Gravity Recovery and Climate Experiment, or GRACE, satellites, which measure changes in the mass of the earth and have been applied to estimate its water content. The technique was groundbreaking two decades ago when the study’s co-author, Jay Famiglietti, who was then a professor at the University of California, at Irvine, used it to pinpoint where aquifers were in decline. Since then, he and others have published dozens of papers using GRACE data, but the question has always lingered: What does the groundwater loss mean in the context of all of the water available on the continents? So Famiglietti, now a professor at Arizona State University, set out to inventory all the land-based water contained in glaciers, rivers and aquifers and see what was changing. The answer: everything, and quickly.

Since 2002, the GRACE sensors have detected a rapid shift in water loss patterns around the planet. Around 2014, though, the pace of drying appears to have accelerated, the authors found, and is now growing by an area twice the size of California each year. “It’s like this sort of creeping disaster that has taken over the continents in ways that no one was really anticipating,” Famiglietti said. (Six other researchers also contributed to the study.) The parts of the world drying most acutely are becoming interconnected, forming what the study’s authors describe as “mega” regions spreading across the earth’s mid-latitudes. One of those regions covers almost the whole of Europe, the Middle East, North Africa and parts of Asia.

In the American Southwest and California, groundwater loss is a familiar story, but over the past two decades that hot spot has also spread dramatically. It now extends through Texas and up through the southern High Plains, where the Ogallala aquifer is depended on for agriculture, and it spreads south, stretching throughout Mexico and into Central America. These regions are connected not because they rely on the same water sources — in most cases they don’t — but because their populations will face the same perils of water stress: the most likely, a food crisis that could ultimately displace millions of people.

“This has to serve as a wake-up call,” said Aaron Salzberg, a former fellow at the Woodrow Wilson Center and the former director of the Water Institute at the University of North Carolina, who was not involved with the study.

Research has long established that people take more water from underground when climate-driven heat and drought are at their worst. For example, during droughts when California has enforced restrictions on delivery of surface water to its farmers — which the state regulates — the enormous agriculture enterprises that dominate the Central Valley have drilled deeper and pumped harder, depleting the aquifer — which the state regulates less precisely — even more.

For the most part, such withdrawals have remained invisible. Even with the GRACE data, scientists cannot measure the exact levels or know when an aquifer will be exhausted. But there is one foolproof sign that groundwater is disappearing: The earth above it collapses as the ground compresses like a drying sponge. The visible signs of such subsidence around the world appear to match what the GRACE data says. Mexico City is sinking as its groundwater aquifers are drained, as are large parts of China, Indonesia, Spain and Iran, to name a few. A recent study (https://www.nature.com/articles/s44284-025-00240-y)by researchers at Virginia Tech in the journal Nature Cities found that 28 cities across the United States are sinking — New York, Houston and Denver, among them — threatening havoc for everything from building safety to transit. In the Central Valley, the ground surface is nearly 30 vertical feet lower than it was in the first part of the 20th century.

When so much water is pumped, it has to drain somewhere. Just like rivers and streams fed by rainfall, much of the used groundwater makes its way into the ocean. The study pinpoints a remarkable shift: Groundwater drilled by people, used for agriculture or urban supplies and then discarded into drainages, now contributes more water to the oceans than melting from each of the world’s largest ice caps.