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.
By pumping water out of the ground and moving it elsewhere, humans have actually shifted such a large mass of water that the Earth tilted nearly 80 centimeters east between 1993 and 2010 alone, changing the planet’s rotational pole, according to a new study published in the American Geophysical Union’s Geophysical Research Letters.
Sea level rise is one of the most significant phenomena associated with the warming climate. Contemporary sea level rise has been monitored extensively by multiple observational techniques.
The research was entitled “Drift of the Earth’s pole confirms groundwater depletion as a significant contributor to global sea level rise 1993-2010.”
Based on climate models, scientists previously estimated humans pumped 2,150 gigatons of groundwater, equivalent to more than six millimeters of sea level rise during this period – but validating that estimate has been 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.”