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| How is extracting groundwater for human use affecting the Earth's circulation? |
Between 1993 and 2010, the Earth's axis of rotation moved about 80 cm to the east.
According to a new study published in Geophysical Research Papers, the journal of the American Geophysical Union, the reason for this is the widespread extraction of large groundwater reserves.
According to this research, groundwater discharge has also affected the sea level.
"Water pumped out of the ground by a motor or pump either evaporates into the air or flows into rivers," study author Ki Won-Seo, a professor of earth sciences at Seoul National University in South Korea, told the BBC. flows away. And finally, it falls into the sea.'
Thus, 'this water joins the sea from land and this process gives rise to redistribution of water.'
Earlier in 2016, water's ability to change the Earth's circulation was discovered.
Another study in 2021 focuses on the tilting of the Earth's axis of rotation and the effects of water loss in the Earth's polar regions, the ice in those regions that melts and flows into the oceans.
But until now there was no research on the effects of groundwater extraction on the Earth's circulation.
Imprints of human action
The pole of the Earth's rotation is the point around which the Earth rotates. Rotation around this axis is called polar rotation. That is when the position of the Earth's axis of rotation is different from that of the surface.
Variations in the position of the Earth's poles are known as polar drift and occur naturally.
Changes in the distribution of Earth's matter cause the axis to move, so the poles, the points around which the Earth's axis rotates, also change.
But since the 1990s the observed shift in the Earth's rotation axis is due to human action.
The distribution of water on Earth affects how matter is distributed on our planet. Scientists say it's like putting a little weight on the rotating part.
In this way, as the water will change its place, there will be some difference in the rotation of the earth.
Researcher Siu says that 'Earth's rotation pole has actually changed a lot.'
"Our research shows that along with the causes of climate change, the distribution of groundwater also plays a major role in the shift of the Earth's rotational pole," he says.
In the research, scientists also found that the distribution of water from the Earth's meridional latitudes (circles parallel to the equator that meet points of equal latitude) has a greater influence on the Earth's axis of rotation.
Most of the water during the study was distributed from western North America to northwestern India, and both regions fall within the mid-latitudes of Maine.
"Efforts by countries around the world to reduce groundwater withdrawals from sensitive areas such as the mid-latitudes could alter changes in the Earth's polar orbit," says Scientist Siu. But this will happen when these efforts continue for several decades.
Effects of groundwater extraction
In the new study, scientists observed changes in the Earth's axis of rotation and the movement of water.
At first, they thought that the distribution of water and the movement of water from one region of the earth to another was due to the melting of ice and glaciers in the polar regions due to climate change, but later they included different scenarios for the distribution of groundwater.
The scientists created a model to account for the changes in the Earth's rotation axis and it matched the recorded tilt of the Earth after the redistribution of 2150 gigatons of groundwater.
Previous research has estimated that humans withdrew 2,150 gigatons of groundwater between 1993 and 2010, equivalent to more than six millimeters of sea level rise.
Surendra Adhikari, a research scientist at NASA's Jet Propulsion Laboratory, says the new research is a good addition.
"They (researchers) have measured the role of groundwater pumping in polar motion, and it is very important."
Adhikari is one of the authors of a 2016 study on the effects of water distribution on Earth's polar ice.
However, Ki-Seo, a professor at Seoul National University and author of the recent study, says that the distribution of water on Earth does not affect the seasons.
He says that the Earth's axis of rotation usually moves a few meters during a year. Therefore, a change in the rotation axis of up to one meter in two decades does not affect the climate.
According to him, the important thing is to "confirm that the extraction of underground water affects the axis of rotation of the earth."
"We present the shift in the axis of circulation as evidence for the effects of groundwater extraction," he says.
'As a father I am worried'
"I am very happy to find an unexplained reason for changes in the Earth's rotation," says Scientist Siu.
"But on the other hand, as an earth dweller and as a father, I am concerned and surprised to learn that groundwater extraction is also a cause of sea level rise."
Intensification of droughts due to climate change may lead to increased groundwater discharge and transport.
Scientists are concerned about the relationship between changes in water bodies and sea level rise.
"This concern is greater because many of us are near coastlines," says SiuThey live.
"My generation has been fine, but my children may be in trouble due to rising sea levels."