The Earth’s axis has tilted by 31.5 inches (nearly 80 centimeters) due to significant groundwater extraction, according to a groundbreaking study published in Geophysical Research Letters. Researchers at Seoul National University linked this tilt to the extensive pumping of groundwater for agricultural and human uses, underscoring the impact of climate-related changes on the planet’s rotation and sea levels.

The study, spanning data from 1993 to 2010, highlights that around 2,150 gigatons of groundwater extraction contributed to this shift in tilt, resulting in approximately 0.24 inches of sea-level rise. Ki-Weon Seo, a geophysicist and study lead, stated, “Our study shows that among climate-related causes, the redistribution of groundwater actually has the largest impact on the drift of the rotational pole.” This highlights the significant influence of human activities on Earth’s physical orientation.

How groundwater affects Earth’s balance

Understanding Earth’s tilt—known as axial precession—requires examining mass distribution, particularly the movement of water across the planet. As glaciers and polar ice sheets melt from Greenland and Antarctica, the resulting water flows toward the equator, which affects the Earth’s balance and driving tilt changes. This movement resembles how a figure skater slows down when they extend their arms outward.

Groundwater, which is water located beneath Earth’s surface in soil pores and rock fractures, is a critical component of the hydrological cycle. This water originates from precipitation that infiltrates into the ground and replenishes underground aquifers, serving as vital freshwater reservoirs for drinking, agriculture, and various industrial processes. Unlike surface water found in rivers and lakes, groundwater remains hidden and is essential for sustained water supply during droughts.

Groundwater usage has become a major part of human activities, especially in agricultural irrigation and urban consumption. Most of the water used eventually ends up in the oceans, which raises questions about resource management and environmental impact in relation to climate change.

While a 31.5-inch shift might seem minor on a human scale, its long-term environmental implications could be significant. Not only could it influence sea-level changes in different regions, but it may also affect Earth’s internal systems, including its magnetic field—an essential shield against harmful solar radiation. These findings connect groundwater extraction to broader environmental challenges, including climate change.

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Researchers like Surendra Adhikari from NASA’s Jet Propulsion Laboratory emphasized the importance of understanding how groundwater pumping influences polar motion. He noted that quantifying this effect is vital for grasping the larger impact humans have on the planet’s geological features. “I’m very glad to find the unexplained cause of the rotation pole drift,” stated Seo, acknowledging both the excitement of discovery and the concerning implications for future climate scenarios.

As this study raises awareness of groundwater’s role, it suggests that effective management strategies are necessary. Future research must prioritize sustainable groundwater use to limit adverse impacts on Earth’s rotation and climate. Initiatives should include enhanced irrigation practices, rainwater harvesting techniques, and thoughtful municipal water management systems, ensuring responsible water conservation.

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