Humans’ groundwater extraction has affected the earth’s rotation: study

Source: The post is based on the article “Humans’ groundwater extraction has affected the earth’s rotation: study” published in The Hindu on 20th June 2023

What is the News?

A study published in the journal Geophysical Research Letters reveals that extensive groundwater extraction by humans has resulted in the earth’s axis tilting nearly 80 cm to the east.

How groundwater extraction influences Earth’s rotation?

Earth’s geographic north and south poles are where its axis intersects the surface. But these poles are not fixed. 

The axis and hence the poles fluctuate due to variations in the Earth’s mass distribution.

In the past, the poles drift was only caused by natural forces like ocean currents and the convection of heated rock deep beneath the Earth. 

But the research in 2016 showed how the movement of water around the world influences the Earth’s rotation.

Like adding a tiny bit of weight to a spinning top, the Earth spins a little differently as water is moved around.

What did the researchers now find out?

Between 1993 and 2010, the excessive pumping of groundwater caused the planet’s rotational pole to shift eastward by approximately 80 centimetres. 

They also found that pumping groundwater from mid-latitude areas would impact the drift the most. The most amount of groundwater redistribution took place in northwest India and western North America both situated at mid-latitudes. 

About Groundwater Depletion in India

Groundwater depletion has been a particular concern across India since the last decade. About 95% of India’s groundwater depletion was traced to north India where groundwater is primarily used for irrigation. 

Punjab, Haryana, Delhi, and western Uttar Pradesh have critical groundwater levels due to the indiscriminate use of groundwater, while Rajasthan and Gujarat have low groundwater levels due to the arid climate. 

Groundwater availability is also low in parts of Karnataka, Tamil Nadu, Telangana, and Andhra Pradesh due to the crystalline nature of the aquifers found here.