SEOUL, SOUTH KOREA – Our water use behavior may have a more significant impact on the Earth than we realize. Recent studies suggest that the pumping of groundwater, particularly for drinking purposes, has led to changes in Earth’s rotation and rising sea levels over the past two decades. This raises concerns about the role of human activity in contributing to climate change.
The rotational pole of the planet, around which Earth rotates, is not stationary. It undergoes a process called polar motion, where its position relative to the crust shifts. This movement is influenced by factors like the distribution of water across the planet. As water is redistributed, it alters the rotation of the Earth, similar to how changing weight distribution affects the spin of a top.
Groundwater, the water hidden underground that collects from rainfall and other sources, plays a crucial role in this process. Unlike water in rivers and lakes, groundwater seeps into natural aquifers, providing a vital source of water during periods of low rainfall. Approximately half of the world’s population relies on groundwater for drinking water, with a third used for irrigation purposes.
Since the 20th century, human activities have significantly increased the exploitation of groundwater reservoirs. The pumping of 2,150 gigatons of groundwater between 1993 and 2010 has been linked to changes in Earth’s rotation. A study conducted by a team of researchers, led by geophysicist Ki-Weon Seo of Seoul National University, demonstrated that the redistribution of groundwater has the most substantial impact on the drift of the rotational pole among climate-related factors.
Seo’s research sheds light on the connection between groundwater use and changes in Earth’s rotation. By modeling observed shifts in the rotational pole and water movement, the study showed that the significant drift in Earth’s rotation could be attributed to the redistribution of groundwater. This finding not only quantifies the impact of groundwater pumping on polar motion but also highlights the implications for climate change mitigation efforts.
Understanding the dynamics of Earth’s rotational pole can provide valuable insights into continent-scale water storage variations. The data on polar motion dating back to the late 19th century offer a historical perspective on hydrological regime changes, potentially linked to climate warming. Seo’s study underscores the importance of considering the effects of human activity on the planet’s natural systems and the urgent need for sustainable water management practices to mitigate climate change.