The global implications of groundwater extraction extend beyond water resource supply concerns. Recent research indicates that such activity has tilted the Earth nearly 80 cm (31.5 inches) east between 1993 and 2010 alone.

The potential of water to alter the Earth’s rotation was discovered in 2016, prompting researchers from Seoul National University (South Korea), University of Melbourne (Australia), Kyungpook National University (South Korea), Hong Kong Polytechnic University (China) and University of Texas at Austin to model the observed changes in the drift of Earth’s rotational pole — the point around which the planet rotates — and the movement of water.

Previous research estimated humans pumped 2,150 gigatons of groundwater, equivalent to more than 6 mm (0.24 inches) of sea level rise, from 1993 to 2010. The analysis published in Geophysical Research Letters first considered only ice sheets and glaciers, and then addressed different scenarios of groundwater redistribution. The model only matched the observed polar drift once 2150 gigatons of groundwater redistribution was included. Without it, the model was off by 78.5 cm (31 inches), or 4.3 cm (1.7 inches) of drift per year.

Redistributing water from the midlatitudes exerts the greatest impact on the rotational pole. During the study period, the most water was redistributed in western North America and northwestern India, both at midlatitudes. The researchers maintain that attempts to slow groundwater depletion rates, especially in these sensitive regions, could theoretically alter the change in drift, but only if such conservation approaches are sustained for decades.

To contact the author of this article, email shimmelstein@globalspec.com