Humans may seem small compared to the massive Earth, but our actions have a significant impact on its dynamics. A recent study published in Geophysical Research Letters reveals that human activity, specifically dam construction, has caused a slight shift in Earth’s rotation over the past two centuries.
Researchers analyzed nearly 7,000 dams built globally from 1835 to 2011 and found that these massive water impoundments have caused Earth’s poles to wander about 3.7 feet away from their original position. The movement is not uniform, shifting based on where the dams were constructed.
The study suggests that while dam-related drift is relatively small compared to other forces shaping polar wander, such as ice melt and sea level rise, it remains an important factor to consider when making projections about future changes in the Earth’s rotation.
According to Natasha Valencic, lead author of the study, “Dams are a smaller contribution to polar wander; maybe an order of magnitude smaller than ice melt. But still, it’s essential to close the budget.” This means that scientists want to understand how different factors interact and contribute to changes in polar wander.
The Earth’s rotation is linked to regional differences in sea levels, with shifts in one direction causing a fall in sea levels in certain hemispheres and an increase in others. Researchers also found that human-driven climate change is affecting polar wander by shifting mass around the globe.
Furthermore, recent studies have shown that human-linked shifts in ice and groundwater are slowing Earth’s rotation at a significant rate. This factor may eventually become more influential than the Moon’s tidal influence on our planet’s rotation.
While the overall effect of dams on polar wander is relatively small, researchers emphasize its importance as a contributing factor to changes in the Earth’s rotation. To fully understand this phenomenon, scientists must continue to study and analyze various factors that impact polar wander.
Source: https://www.404media.co/humans-have-shifted-earths-rotation-scientists-discover-heres-how