[Rockhounds] We've pumped so much groundwater that we've nudged the Earth's spin

[Kreigh Tomaszewski]

By pumping water out of the ground and moving it elsewhere, humans have
shifted such a large mass of water that the Earth tilted nearly 80
centimeters (31.5 inches) east between 1993 and 2010 alone, according to a
new study published in *Geophysical Research Letters*.

Based on climate models <https://phys.org/tags/climate+models/>,
scientists previously
estimated <https://doi.org/10.1029/2010GL044571> humans pumped 2,150
gigatons of groundwater, equivalent to more than 6 millimeters (0.24
inches) of sea level rise, from 1993 to 2010. But validating that estimate
is difficult.

One approach lies with the Earth's rotational pole, which is the point
around which the planet rotates. It moves during a process called polar
motion, which is when the position of the Earth's rotational pole varies
relative to the crust. The distribution of water on the planet affects how
mass is distributed. Like adding a tiny bit of weight to a spinning top,
the Earth spins a little differently as water is moved around.

"Earth's rotational pole actually changes a lot," said Ki-Weon Seo, a
geophysicist at Seoul National University who led 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."

https://phys.org/news/2023-06-weve-groundwater-nudged-earth.html