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When people pump groundwater, it significantly affects the tilt of the Earth's rotation.
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Additionally, a study documents how much impact groundwater pumping has on climate change.
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Understanding this relatively recent data can provide better insight into how to prevent sea level rise.
Water has power. So much force, in fact, that pumping Earth's groundwater can change the planet's tilt and rotation. It could also impact sea level rise and other impacts of climate change.
Pumping groundwater appears to have greater consequences than once thought. But now – thanks to a study published in the journal Geophysical research letters—we can see that the Earth has tilted 3 feet (91.5 centimeters) in less than twenty years due to groundwater pumping. This corresponds to a sea level rise of 24 centimeters.
“Earth's rotation pole is actually changing a lot,” Ki-Weon Seo, a geophysicist at Seoul National University and research leader, said in a statement. “Our research shows that of the climate-related causes, groundwater redistribution actually has the greatest impact on the drift of the rotation pole.”
As the Earth moves on a rotating pole, the distribution of water on the planet affects the distribution of its mass. “Just like adding a little bit of weight to a spinning top,” the authors say, “the Earth spins a little differently as the water moves.”
NASA research published in 2016 alerted us to the fact that the distribution of water can change the Earth's rotation. This study in Geophysical research letters tries to add some hard figures to that realization. “I am very happy to have discovered the unexplained cause of the rotation pole deviation,” said Seo. “On the other hand, as an inhabitant of the Earth and as a father, I am concerned and surprised to see that groundwater pumping is another source of sea level rise.”
The study included data from 1993 through 2010 and showed that pumping as much as 2,150 gigatons of groundwater caused a change in the Earth's slope of about 3 feet. The pumping is largely for irrigation and human use, ultimately moving groundwater to the oceans.
In the study, researchers modeled observed changes in the drift of Earth's rotation pole and the movement of water. In several scenarios, the only model that matched the drift was one that included 2,150 gigatons of groundwater distribution.
Surendra Adhikari, a research scientist at NASA's Jet Propulsion Laboratory who was involved in the 2016 study, says the additional research is important. “They have quantified the role of groundwater pumping on polar movement,” he said in a press release, “and it is quite significant.”
Where the water moves matters. Redistributing water from the mid-latitudes makes the biggest difference, so our intense water movement from both western North America and northwestern India has played a key role in the tilt changes.
With the impact of water movements known for such a short time (and relatively recently), searching through historical data can help reveal trends and provide greater depth in understanding the effects of groundwater movements.
“Observing changes in Earth's rotation pole is useful,” says Seo, “for understanding variations in water storage at the continent scale.”
This data can also help conservationists understand how to work to avert continued sea level rise and other climate problems. Hopefully the changes can be implemented appropriately over time.
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