Humans have pumped enough groundwater to change Earth's spin
What in the Earth?
A new study has found that humans pumped so much water out of the ground over 17 years that Earth has tilted nearly 3 feet to the east.
“Earth’s rotational pole actually changes a lot,” lead author Ki-Weon Seo, a geophysicist at Seoul National University in South Korea, said in a statement. “Our study shows that among climate-related causes, the redistribution of groundwater actually has the largest impact on the drift of the rotational pole.”
Researchers previously estimated humans pumped 2,150 gigatons of groundwater between 1993 and 2010, equivalent to a quarter-inch of sea-level rise.
The study published Thursday in the journal Geophysical Research Letters found that most of the water during that period was redistributed in western North America and northwestern India.
Researchers previously estimated humans pumped 2,150 gigatons of groundwater between 1993 and 2010, equivalent to a quarter-inch of sea level rise. agupubs.onlinelibrary
Water’s role in changing Earth’s rotation was only discovered in 2016, and the researchers noted this is the first time someone has quantified the role of groundwater pumping on polar motion.
Polar motion is the movement of the Earth’s rotational axis in relation to its crust.
The scientists initially only took the melting of glaciers and ice caps into account while studying the drift of Earth’s rotational pole. Subsequent models included the 2,150 gigatons of groundwater.
The model was off by 31 inches — or 1.7 inches of drift per year — without that water calculation.
“I’m very glad to find the unexplained cause of the rotation pole drift,” Seo said. “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.”
The location of the groundwater matters. The scientists found that redistributing water from the midlatitudes — the region roughly between 35 and 65 degrees north or south of the equator — has a greater effect on the rotational pole.
Scientists initially only took the melting of glaciers and ice caps into account while studying the drift of Earth’s rotational pole. Subsequent models included the 2,150 gigatons of groundwater. agupubs.onlinelibrary
The researchers worry that long-term polar drift will affect Earth’s climate. Getty Images/iStockphoto
Researchers worry that long-term polar drift will affect Earth’s climate, as it would take significant, sustained change to stop this trend.
They plan to analyze historical data to look to the future.
“Observing changes in Earth’s rotational pole is useful for understanding continent-scale water storage variations,” Seo said. “Polar motion data are available from as early as the late 19th century. So, we can potentially use those data to understand continental water storage variations during the last 100 years. Were there any hydrological regime changes resulting from the warming climate? Polar motion could hold the answer.”
Source: New York Post
