Humans pump so much groundwater that Earth’s axis has shifted, study finds.
Humans’ unquenchable thirst for groundwater has sucked so much liquid from subsurface reserves that it’s affecting Earth’s tilt, according to a new study.
Groundwater provides drinking water for people and livestock, and it helps with crop irrigation when rain is scarce. However, the new research shows that persistent groundwater extraction over more than a decade shifted the axis on which our planet rotates, tipping it over to the east at a rate of about 1.7 inches (4.3 centimeters) per year.
That shift is even observable on Earth’s surface, as it contributes to global sea level rise, researchers reported in the study published June 15 in the journal Geophysical Research Letters.
“Earth’s rotational pole actually changes a lot,” said lead study author Ki-Weon Seo, a professor in the department of Earth science education at Seoul National University in South Korea, in a news release. “Our study shows that among climate-related causes, the redistribution of groundwater actually has the largest impact on the drift of the rotational pole.”
Earth’s drifting axis
You might not be able to feel Earth’s rotation, but it’s spinning on a north-south axis at a rate of about 1,000 miles per hour (1,609 kilometers per hour).
The ebb and flow of seasonal change is linked to the angle of the planet’s rotational axis, and over geologic time, a wandering axis could affect climate on a global scale, said Surendra Adhikari, a research scientist at NASA’s Jet Propulsion Laboratory, in the release. Adhikari was not involved in the study.
Earth’s interior is layered with rock and magma surrounding a dense, hot core. But in the outermost rocky layer, there are also vast quantities of water. Below the planet’s surface, rocky reservoirs known as aquifers are estimated to contain over 1,000 times more water than all the surface rivers and lakes in the world.
