Scientists have discovered that human-made dams around the world have led to a noticeable shift in the Earth’s poles, moving them away from their rotational axis. Over the past 200 years, nearly 7,000 massive dams have been built, which has redistributed mass on the planet and caused the poles to move about three feet off-center.
The phenomenon is known as true polar wander, where the outermost rock layer of the Earth’s crust wobbles relative to its molten interior. This movement affects the surface locations of the Earth’s poles, causing them to pass through different regions than before.
According to a new study published in Geophysical Research Letters, the amount of water stored behind dams has a significant impact on the planet’s mass distribution. Researchers analyzed a global database of dams and found that 6,862 large dams built between 1835 and 2011 have contributed to a decrease in sea levels by about 0.83 inches.
The study revealed two phases of dam construction: the first phase, from 1835 to 1954, coincided with a boom in dam building in North America and Europe, causing the North Pole to shift about eight inches towards the equator. The second phase, between 1954 and 2011, saw most dams built in Asia and East Africa, resulting in a 22-inch shift of the North Pole towards western South America and the South Pacific.
While the effects are relatively subtle, the study highlights the need for researchers to account for water stored in dams when predicting future sea level rise. The scientists warn that the geometry of sea level rise will change depending on where dams and reservoirs are placed, which can lead to significant changes in coastal regions.
Source: https://gizmodo.com/human-constructed-dams-have-shifted-the-earths-poles-scientists-say-2000627912