Humans suck water from the ground quickly enough to move Earth's axis, a new study said.
What's happening?
Between 1993 and 2010, the tilt of the Earth shifted by 31.5 inches, corresponding with people's worldwide withdrawals of underground water. Researchers published the findings in June in the journal Geophysical Research Letters.
Based on prior research, people pumped an estimated 2,150 gigatons of water from the natural ground reservoirs called aquifers during the study's time frame. That's enough to fill 860 million Olympic pools, The Washington Post noted.
The study said this amount of water equates to a global sea-level rise of about a quarter-inch. Displacement of this water, much of which serves irrigation purposes and ultimately flows to oceans, has happened faster than aquifer replenishment.
It has also likely caused the world to wobble more. The journal Science's news section likens the motion to a spinning top or basketball on a finger having weight redistributed. This metaphorical basketball also has water-balloon-like properties of "sloshing" slightly.
Why is the finding about groundwater use affecting pole position important?
Earth's axis — the imaginary tilted "pole" around which the world spins — shifts with weight redistribution, and that's not news. Some of the change in tilt relative to the Earth's surface is a natural process, and scientists have already observed divergence from this. They previously linked discrepancies to factors including melting glaciers, ice sheets, and water held behind dams, The New York Times reported.
"Earth's rotational pole actually changes a lot," Ki-Weon Seo, the Seoul National University geophysicist who led the new study, said in a statement.
However, the pattern of the observed shift has still been a mystery, Space.com reported. That's where the new study comes in. What especially concerns its authors is that the pole shift suggests groundwater depletion's role in sea level change is significant.
"Our study shows that among climate-related causes, the redistribution of groundwater actually has the largest impact on the drift of the rotational pole," Seo said in the statement.
"I'm very glad to find the unexplained cause," he added. "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."
What can I do to use less groundwater?
Maintaining healthy groundwater supplies is helpful not just to avoid extra Earth wobble but also to keep ground from sinking and ensure people have enough for drinking and farming. These reasons intensify in our warming world.
Many organizations have tips to protect and save water, including choosing water-sipping plantings, making prompt leak repairs, and using water-saving products. These actions usually have the added benefit of saving you money while helping the planet.
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