Earth's Axis Tilted Noticeably Over Two Decades. Here's Why

If you've felt a bit off balance, you can blame your fellow humans: The pumping of groundwater caused the Earth to tilt 31.5 inches over a 17-year period, or about 1.8 inches per year.

As reported in recent days by outlets including Popular Science and USA Today, more than a year after the research was published in the journal Geophysical Research Letters, the pumping of 2,150 gigatons of groundwater over the period of study from 1993 to 2010 shifted the Earth's tilt more than two feet. One gigaton of water represents about 2.2 trillion pounds of water, or a billion metric tons. 

Most of the groundwater pumping is for farming irrigation and the water we use for drinking, bathing and other domestic and industrial uses. Redistributing the water from its natural courses appears to be what causes the effect.

The Earth has ...