Why has Earth’s pole moved? What’s the connection to India?

The Earth’s pole has moved – and India has played a part in it. According to a new study published in Geophysical Research Letters, the Earth’s pole has shifted around 80 centimetres over the last thirty years. But why has this happened? And what does it have to do with India? Let’s take a closer look: What happened? According to Phys.org, the Earth’s pole shifted nearly 80 centimetres east between 1993 and 2010. The cause of this?

Groundwater being pumped.

According to Axios, the direction of Earth’s rotational axis shifted in the 1990s. It was thought that this occurred due to glacial melt, groundwater removal and other activities that contribute to an increase in sea level. But in 2016, researchers discovered water’s ability to change the Earth’s rotation, as per Phys.org. Until then the specific contribution of groundwater to these rotational changes remained unexplored. According to the website, scientists previously projected that human beings pumped 2,150 gigatons of groundwater – equivalent to more than six millimetres of sea level rise – from 1993 to 2010. However, validating that estimate is difficult. “Earth’s rotational pole actually changes a lot,” Ki-Weon Seo, a geophysicist at Seoul National University in South Korea, told the website. “Our study shows that among climate-related causes, the redistribution of groundwater actually has the largest impact on the drift of the rotational pole,” Seo, who led the study, added. As per Down To Earth, the Earth’s north and south poles as well as the axis are not fixed – they vary due to changes in the Earth’s mass distribution. As per Axios, researchers modelled the observed changes in the drift of Earth’s rotational pole and the movement of water – at first with only ice sheets and glaciers considered. Seo told Nature.com that adding the effects of changes in surface reservoirs did not help “so I just scratched my head and said, ‘probably one effect is groundwater’”. That was when they found that groundwater distribution (2150 gigatons) needed to be included in the model for it to match observations of the shift. The model only matched the observed polar drift once the researchers included 2150 gigatons of groundwater redistribution. What does it have to do with India? The research found that the most water was redistributed in western North America and northwestern India.

“I’m very glad to find the unexplained cause of the rotation pole drift,” Seo told Phys.org.

“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.” “Earth’s pole has drifted toward 64.16°E at a speed of 4.36 cm/yr during 1993–2010 due to groundwater depletion and resulting sea level rise,” the authors noted, as per Axios. The researchers said attempts by countries to slow groundwater depletion rates, especially in those sensitive regions, could theoretically alter the change in drift, but only if such conservation approaches are sustained for decades. The rotational pole normally changes by several metres within about a year, so changes due to groundwater pumping do not run the risk of shifting seasons. However, on geologic time scales, polar drift can have an impact on climate, they said. “Observing changes in Earth’s rotational pole is useful for understanding continent-scale water storage variations,” Seo further told Phys.org. “Polar motion data are available from as early as the late 19th century. So, we can potentially use those data to understand continental water storage variations during the last 100 years. Were there any hydrological regime changes resulting from the warming climate? Polar motion could hold the answer.” “This is a nice contribution and an important documentation for sure," said Surendra Adhikari, a research scientist at NASA’s Jet Propulsion Laboratory, US, who was not involved in this study. Adhikari published the 2016 paper on water redistribution impacting rotational drift. “They have quantified the role of groundwater pumping on polar motion, and it’s pretty significant,” Adhikari said in a statement. Down To Earth quoted a study published in the same journal as finding that polar drift moved southward to eastward in 1995. The average drift speed between 1995 and 2020 was 17 times quicker than from 1981-1995, as per the website. Humans have extracted 18 trillion tonnes of water from aquifers without replacing it, the study noted. With inputs from agencies Read all the  Latest News,  Trending News,  Cricket News,  Bollywood News, India News and  Entertainment News here. Follow us on  Facebook,  Twitter and  Instagram.