A new study from Harvard University analyzes how dam building—primarily the two stages that spanned from 1835 to 2011—has caused the Earth’s poles to move roughly three feet. In addition to changing the Earth’s rotation, dams have caused a global decrease in water levels. They drastically disturb natural ecosystems, negatively impact water quality, and exacerbate soil erosion—oh, and they’ve also altered the location of the Earth’s poles. Between 1835 and 1954, a majority of dams were constructed in North America and Europe, moving the North Pole 8 inches to the 103rd meridian east. Dams aren’t the only anthropomorphic force at work impacting the orientation of the Earth’s poles, however.