The positions of the Earth's two true poles (not magnetic poles) were found to have changed between 1835 and 2011 due to the construction of 6,862 dams, according to a study led by researchers from Harvard University. What makes this study interesting is that the poles changed in the opposite direction between 1835 and 1954 and between 1954 and 2011.
Between 1835 and 1954, the North Pole moved 20.5 cm towards the 103rd meridian east due to the construction of dams in North America and Europe. Then between 1954 and 2011, it moved 57 cm towards the 117th meridian west due to the construction of dams in East Africa and Asia. In a period of 176 years, the pole position changed by 113 cm.
The construction of nearly 7,000 dams in 176 years has also caused sea levels to fall by 21mm, even though sea levels have risen by 1.2mm per year since the 20th century. China has begun construction of the world's largest dam in Tibet this year, which will certainly cause the Earth's poles to shift again.
Previously, studies have shown that the Earth is spinning faster due to melting ice. Human activity is causing climate change and now we have evidence that it is also causing changes in the Earth's movement and poles.
The study was published in the journal Geophysical Research Letters.