Human impact causes 31.5-inch shift in Earth's axis

Massive groundwater pumping adds 0.24 inches to sea levels, affecting Earth’s rotation

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New findings reveal that humans’ massive extraction of groundwater is causing Earth’s axis to tilt, shifting it by approximately 31.5 inches (0.8 metres) since 1993. Published in Geophysical Research Letters, the study links this shift to our planet’s “rotational drift” and the redistribution of water from underground reserves to the oceans.

As the Earth continues to shift in response to human activity, these changes impact sea levels, climate systems, and the planet’s rotation itself.

“Among climate-related causes, the redistribution of groundwater has the largest impact on this drift,” said Ki-Weon Seo, a geophysicist at Seoul National University and the lead researcher.

The study underscores how human activities—specifically groundwater pumping—are altering planetary mechanics in ways scientists are only beginning to fully understand.

Global Shift: Earth Tilting Due to Water Redistribution

The massive extraction of groundwater has regional hotspots, primarily in areas like western North America and northwestern India, which rely heavily on these underground reserves for agriculture, drinking water, and industrial use.

The redistributed water doesn’t remain local. Instead, it flows into rivers, eventually reaching oceans and contributing directly to sea level rise. Although the estimated 0.24 inches (0.61 cm) might appear minor, it accelerates when combined with the melting ice caps, further driving sea levels higher than anticipated.

As Seo explained, “The Earth spins a little differently as water is moved around,” likening it to a spinning top shifting weight mid-spin. This redistribution creates a “wobble” effect, slowly altering the angle of Earth’s rotational axis.

Climate and Timekeeping Impacts

The consequences of this shift extend beyond environmental impact to something as foundational as timekeeping. The Earth’s rotational axis directly influences timekeeping systems, and with the Earth’s rotation affected, these changes may interfere with the anticipated leap second adjustment scheduled for 2026.

With the updated timeline, scientists project that this correction may need to be delayed until 2029, reflecting how seemingly unrelated aspects—climate change and time—are intricately interconnected.

These axis shifts affect the planet in various ways: they modify tidal patterns, impact global weather, and influence climate stability. As Seo emphasised, the new findings build on existing research but suggest an even greater role for groundwater pumping in shifting the Earth’s rotation.

Human Activity Drives Unexpected Planetary Shifts

While research in 2016 suggested that groundwater pumping might influence Earth’s axis, this new study quantifies its influence on polar drift, identifying it as a major driver of Earth’s rotational changes. This tilt shift may also amplify concerns over rising sea levels and bring unexpected consequences to coastlines and vulnerable areas worldwide.

“I’m very glad to find the cause of the rotational pole drift,” Seo remarked. “But as a resident of Earth and a father, I’m concerned that pumping groundwater is yet another source of sea-level rise.”

Wake-Up Call for Sustainable Water Use

This research marks a wake-up call for sustainable water practices. With every litre extracted, humans impact planetary stability, shifting coastlines, ecosystems, and even our perception of time. As individuals and policymakers, understanding this water-climate connection is essential for guiding conservation efforts and slowing these changes.

Future research and policies must focus on sustainable water management, balancing human consumption with the preservation of natural resources. Potential solutions include better irrigation practices, rainwater harvesting, and improved municipal water systems. Nations may also need to collaborate on global water policies to ensure an equitable distribution of resources and to protect vulnerable ecosystems.

As our knowledge of groundwater pumping’s planetary impacts grows, so does the responsibility to act. “This isn’t just about rising seas or shifting poles,” said Seo. “It’s about the future of Earth.”