Earth’s pole has moved and India’s water scarcity had a big hand in it
Excess groundwater exploitation in India and the US has led to Earth being tilted nearly 80 centimeters eastward, scientists have estimated based on new climate models.
New Delhi,UPDATED: Jun 19, 2023 11:39 IST
Humans have shifted such a large mass of water that the Earth tilted nearly 80 centimeters. (Photo: Isro)
Humans have pumped out 2,150 gigatons of groundwater As water moves around on Earth, it can cause changes in how our planet spins
Earth’s rotational pole actually changes a lot
By India Today Science Desk: Humans have pumped so much water out of the ground that it has effectively affected Earth’s spin, and the pole has drifted at a speed of 4.36 centimeters per year between 1993 and 2010.
This has led to Earth being tilted nearly 80 centimeters eastward, scientists have estimated based on new climate models.
The study published in the Geophysical Research Letters states that an important anthropogenic contribution is sea level rise due to groundwater depletion resulting from irrigation. “Earth’s pole has drifted toward 64.16 degrees E at a speed of 4.36 centimeters per year during 1993–2010 due to groundwater depletion and resulting sea level rise,” the paper read.
The international team of researchers estimated that humans have pumped out 2,150 gigatons of groundwater, equivalent to more than 0.24 inches of sea level rise, though they acknowledged that estimating the exact figure is difficult.
One way to understand this is by looking at the Earth’s rotational pole. This is the point around which the Earth spins. It actually moves slightly over time in a process called polar motion.
This means that the position of the Earth’s rotational pole changes relative to the Earth’s outer layer (crust). The way water is distributed on our planet affects how mass is spread out. It’s similar to what happens when you add a small weight to a spinning top – it starts to spin a bit differently because of the added weight.
Similarly, as water moves around on Earth, it can cause slight changes in how our planet spins.
Researchers compare the observed polar motion (red arrow, “OBS”) to the modeling results without (dashed blue arrow) and with (solid blue arrow) groundwater mass redistribution. (Photo: Geophysical Research Letters)
“We show that the model estimate of water redistribution from aquifers to the oceans would result in a drift of Earth’s rotational pole, about 78.48 cm toward 64.16°E,” the paper read.
“Earth’s rotational pole actually changes a lot. Our study shows that among climate-related causes, the redistribution of groundwater actually has the largest impact on the drift of the rotational pole,” Ki-Weon Seo, a geophysicist at Seoul National University who led the study, said in a statement released by the American Geophysical Union.
Researchers maintained that the location of the aquifers (groundwater) also matters for Earth’s spin to change. The team estimated that during the period of the study, most water was redistributed in western North America and northwestern India.
While the slight drifting of the pole will not have an impact on the seasons, researchers cautioned that over a longer geologic time period, it could have an impact on the climate.