The way the Earth’s rotation is affected by human activity has been fundamentally redefined, particularly through the extensive pumping of groundwater. This process has caused significant shifts, leading to sea level rise of 0.24 inches in under 20 years and a tilt in Earth’s axis by approximately 31.5 inches.
This discovery is outlined in a study published in Geophysical Research Letters, which investigates how groundwater redistribution impacts Earth’s rotation and the global water balance.
Ki-Weon Seo, a geophysicist at Seoul National University and the study’s lead author, explained:
“Earth’s rotational pole actually changes a lot. Our study shows that among climate-related causes, the redistribution of groundwater actually has the largest impact on the drift of the rotational pole.”
The research highlights how water movement affects the planet’s mass, comparing it to the effect of adding weight to a spinning top. As water is extracted and redistributed, Earth’s spin changes slightly but measurably. The study identifies western North America and northwestern India as the regions most affected, with midlatitude groundwater extraction having the greatest influence on Earth’s rotation.
This work builds on prior research from 2016, which first proposed the concept. The findings also deepen concerns over climate impacts, especially as they relate to sea level rise.
Sea expressed his dual perspective:
“I’m very glad to find the unexplained cause of the rotation pole drift. On the other hand, as a resident of Earth and a father, I’m concerned and surprised to see that pumping groundwater is another source of sea-level rise.”
Adding to this, recent research from 2024 suggests that polar ice melt could also alter Earth’s spin. These combined changes may delay the planned addition of a “leap second” to Coordinated Universal Time (UTC) from 2026 to 2029, reflecting the far-reaching consequences of human activity on planetary systems.