Groundwater removal tilted Earth 31.5 inches

• When a large mass of water is moved, the planet's center of gravity also moves.

What's new: Researchers at Seoul National University determined "the redistribution of groundwater actually has the largest impact on the drift of the rotational pole," geophysicist Ki-Weon Seo said in a press release.

• The researchers modeled how the drift in Earth's rotational axis changed and how water moved from the melting of ice sheets and glaciers as well as the redistribution of groundwater.
• They found the distribution of groundwater had to be included in the model for it to match observations of the shift.
• "Earth's pole has drifted toward 64.16°E at a speed of 4.36 cm/yr during 1993–2010 due to groundwater depletion and resulting sea level rise," the authors report.

The impact: Changes in the rotational pole due to groundwater pumping aren't expected to shift the planet's seasons, Surendra Adhikari, a research scientist at the Jet Propulsion Laboratory who was not involved in the study, said in the release.

• It normally drifts several meters in a year and the groundwater contribution is on the order of centimeters.
• Over time, though, the drift could affect the planet's climate, Adhikari says.