Pumping groundwater changed Earth’s tilt by 80cm in 17 years
Between 1993 and 2010, humans moved such a large mass of water by pumping it out of the ground that our planet tilted almost 80cm to the east – according to the edition Geophysical Research Letters, TASS reports
“Earth's rotational pole actually changes a lot. Our study shows that among climate-related causes, the redistribution of groundwater actually has the largest impact on the drift of the rotational pole,” explains Professor Ki-Weon Seo, lead author of the paper, a geophysicist at Seoul National University.
Scientists discovered the impact of water on the Earth’s axis back in 2016, but the contribution of groundwater to these changes has not yet been studied. In the new study, the science team created a computer model of the observed changes in the tilt of the Earth’s rotational pole and the movement of water. At first, the modelling included only ice sheets and glaciers, and then also various groundwater redistribution scenarios.
The resulting picture began to match the observed changes in the Earth’s axis only after the researchers included 2,150 gigatonnes of displaced groundwater. Without them, the model deviated from the real changes by 78.5cm.
The Earth’s rotational pole usually shifts by about a few metres during the year, the authors noted. Therefore, changes due to groundwater pumping do not carry a global risk, e.g., the change of seasons. But on a geologic time scale, a change in the tilt of the planet could have an impact on climate, the scientists concluded.