Pumping huge amounts of groundwater does more than affect local water supplies. According to a 2023 study, groundwater depletion between 1993 and 2010 contributed to a shift of about 31.5 inches (80 centimeters) in Earth’s rotational pole.
This occurs because the pole is constantly moving. As water, ice, and other masses are redistributed around the globe, the planet responds with subtle changes in the position of its rotation axis. These movements are tiny on a global scale, yet they can be measured with remarkable precision.
For years, scientists have worked to understand what drives these changes. Melting ice sheets and ocean circulation are known contributors, but groundwater has emerged as another important piece of the puzzle. Research now suggests that the water humans pump from underground aquifers has had a measurable effect on Earth’s wobble.
Billions Of Tons Of Groundwater Were Moved
According to a study published in Geophysical Research Letters, researchers estimated that around 2,150 gigatons of groundwater were depleted worldwide between 1993 and 2010. Much of that water was pumped for irrigation and human consumption before eventually making its way into rivers and, ultimately, the oceans.
When scientists added this groundwater loss to their models of polar motion, the results closely matched the drift that had actually been observed. The study estimated that groundwater depletion contributed to a shift of roughly 31.5 inches (80 centimeters) in Earth’s rotational pole during the 17-year period. The same amount of groundwater loss was also linked to approximately 6.24 millimeters of global sea-level rise.
“Earth’s rotational pole actually changes a lot,” said Ki-Weon Seo, a geophysicist at Seoul National University and lead author of the study. “Our study shows that among climate-related causes, the redistribution of groundwater actually has the largest impact on the drift of the rotational pole.”
Why Moving Water Changes The Way Earth Spins
The idea may sound surprising, but the physics behind it are fairly simple. Earth’s rotation is influenced by how mass is distributed across the planet.
According to NASA, the effect can be compared to adding weight to one side of a spinning top. The top keeps spinning, but its motion changes slightly because its balance has shifted. Earth works in much the same way.
Water stored underground is part of the planet’s mass. When that water is removed from aquifers and eventually reaches the oceans, the balance changes. The effect is small, but modern observations are sensitive enough to detect it.
The researchers found that where groundwater is removed matters too. Heavy depletion in western North America and northwestern India appeared to play a particularly important role in the modeled pole drift. Water losses from midlatitude regions tend to have a stronger impact on polar motion than losses elsewhere.
Scientists Are Still Piecing Together The Full Picture
As explained in a 2026 study published in the Journal of Geodesy, changes in water stored on land remain an important part of the picture. The researchers found that long-term shifts were driven mainly by changes in snow storage and Greenland’s ice melt, while groundwater played a smaller role in their model.
Scientists are also expanding the historical record. In 2026, researchers introduced two new reconstructions of terrestrial water storage: TWSTORE, which begins in 1984, and ML-TWiX, which covers the period from 1980 to 2012. These tools are designed to improve understanding of water-storage changes before the satellite era provided more detailed observations.
Despite advances in observation and reconstruction tools, many uncertainties remain. Polar motion results from a complex mix of interconnected processes. Still, the groundwater study highlights that human-driven water extraction can leave a measurable mark on the planet itself.
“Observing changes in Earth’s rotational pole is useful,” Seo said, “for understanding continent-scale water storage variations.”
