By pumping groundwater, humans have shifted the distribution of the water on Earth enough to alter the planet’s tilt, a new study finds.
Previous research estimated that, between 1993 to 2010, humans pumped more than 2 trillion tons of groundwater. That water flowed to cities and farms before emptying out to sea, raising global sea levels by around a quarter of an inch, the study suggested.
New research finds evidence of this shift in the changing position of the Earth’s rotational pole — the point around which the planet spins. Comparing a computer model of the rotational pole with observed changes in its position, scientists found that the pole’s recent drift could not be fully explained without the effect of groundwater pumping.
From 1993 to 2010, they determined, humans redistributed enough water to move the rotational pole roughly 31 inches. The findings were published in the journal Geophysical Research Letters.
“I’m very glad to find the unexplained cause of the rotation pole drift,” Ki-Weon Seo, a geophysicist at Seoul National University and lead author of the study, said in a statement. “On the other hand, as a resident of Earth and a father, I’m concerned and surprised to see that pumping groundwater is another source of sea-level rise.”