Earth's poles shift by 80 centimeters: Groundwater depletion plays a key role
New Delhi : In a groundbreaking study published in Geophysical Research Letters, scientists have discovered that the Earth's pole has shifted approximately 80 centimeters over the past three decades. Surprisingly, this shift is closely tied to the activities in India.
According to Phys.org, between 1993 and 2010, the Earth's pole moved nearly 80 centimeters eastward. Axios reports that this change in direction occurred due to a shift in the Earth's rotational axis during the 1990s. Initially, researchers attributed this shift to glacial melt and other factors related to rising sea levels. However, it wasn't until 2016 that the role of groundwater in altering the Earth's rotation was recognized.
Previous estimates suggested that human activities, such as groundwater pumping, contributed to a rise in sea levels by approximately 6 millimeters between 1993 and 2010. However, validating this estimation proved challenging. Ki-Weon Seo, a geophysicist from Seoul National University in South Korea, led the study and explained that "the redistribution of groundwater actually has the largest impact on the drift of the rotational pole."
The Earth's poles and rotational axis are not fixed but instead vary due to changes in the distribution of the Earth's mass. To understand the observed changes, researchers conducted modeling experiments considering the movement of ice sheets and glaciers alone. However, the model did not match the observed polar drift until they included the redistribution of 2150 gigatons of groundwater.
Remarkably, the study found that the highest water redistribution occurred in western North America and northwestern India. This discovery raises concerns about groundwater depletion and its contribution to sea-level rise. The authors of the study noted that attempts to slow down groundwater depletion rates, particularly in sensitive regions, could potentially influence the pole shift. However, sustained conservation efforts over decades would be required to achieve significant changes.
While changes in the Earth's rotational pole do not immediately impact the seasons, they can have long-term climate effects over geological time scales. The study's findings also hold promise for understanding variations in continental water storage over the last century, shedding light on hydrological regime changes resulting from climate warming.
Surendra Adhikari, a research scientist at NASA's Jet Propulsion Laboratory, praised the study, stating, "They have quantified the role of groundwater pumping on polar motion, and it's pretty significant." Additionally, another study published in the same journal revealed that polar drift moved southward to eastward in 1995, with the average drift speed from 1995 to 2020 being 17 times faster than from 1981 to 1995.
Overall, this research emphasizes the vital role of groundwater redistribution in the Earth's pole shift. The implications for sea-level rise and climate change underscore the importance of sustainable practices to mitigate these effects.
