Humans pump so much groundwater that Earth’s axis has shifted, study finds

Groundwater extraction shifted the Earth’s axis: What a new study says

Groundwater is a vital resource for drinking, irrigation and other human needs. But extracting too much of it can have unexpected consequences for the planet. A new study has found that humans have pumped out so much groundwater that it has slightly shifted the Earth’s rotational axis.

What is polar motion?

Earth spins around an imaginary axis that passes through the north and south poles. This axis is not fixed, but changes over time due to various factors that affect the distribution of mass on and inside the planet. This phenomenon is known as polar motion.

Polar motion can be caused by natural processes such as the movement of rocks in the mantle, ocean currents, atmospheric winds and even earthquakes and volcanoes. But human activities can also influence polar motion by altering the balance of water on land and in the oceans.

How does groundwater extraction affect polar motion?

Groundwater is stored in underground reservoirs called aquifers, which can hold more than 1,000 times the amount of water in all the surface rivers and lakes in the world. When humans pump out groundwater for various purposes, they reduce the mass of water on land and increase the mass of water in the oceans. This changes the center of gravity of the Earth and causes a slight tilt in its rotational axis.

A team of researchers from South Korea, Australia, Hong Kong and the USA analyzed data from satellite observations and hydrological models to estimate how much groundwater humans have extracted between 1993 and 2010. They found that humans pumped out around 2,150 gigatons of groundwater, mostly in western North America and northwestern India. This amount of water would raise global sea level by about 6 millimeters if poured into the ocean.

The researchers also calculated how this groundwater extraction affected polar motion. They found that it caused the Earth’s axis to drift eastward by about 4.36 centimeters per year, accounting for about 30% of the total observed polar motion during that period. The study was published in the journal Geophysical Research Letters earlier this month.

Why does it matter?

The shift in Earth’s axis due to groundwater extraction is not significant enough to have any noticeable impact on our daily lives or climate. However, it shows how humans have altered the planet’s natural systems and cycles by exploiting its resources. It also highlights the need for sustainable management of groundwater resources, which are essential for human well-being and food security.

Groundwater extraction can have other negative effects such as land subsidence, saltwater intrusion, reduced streamflow and biodiversity loss. Moreover, groundwater depletion can exacerbate the effects of climate change, such as droughts, floods and sea level rise.

Therefore, it is important to monitor and regulate groundwater use, conserve water and adopt alternative sources of water supply where possible. By doing so, we can not only protect our precious groundwater resources, but also reduce our impact on Earth’s rotation and stability.

Source: 

(1) Groundwater extraction linked to drift in Earth's rotational pole. https://interestingengineering.com/science/groundwater-extraction-linked-to-drift-in-earths-rotational-pole.

(2) Groundwater extraction shifted the Earth’s axis: What a new study says. https://www.msn.com/en-in/news/in-depth/groundwater-extraction-shifted-the-earth-s-axis-what-a-new-study-says/ar-AA1dePLY.

(3) Humans pump so much groundwater that Earth’s axis has shifted, study finds. https://www.msn.com/en-us/news/technology/humans-pump-so-much-groundwater-that-earth-s-axis-has-shifted-study-finds/ar-AA1d4GoX.

(4) Earth’s axis has shifted. Why using groundwater is to blame. https://www.msn.com/en-us/news/technology/earth-s-axis-has-shifted-why-using-groundwater-is-to-blame/ar-AA1d7CIs.

(5) Groundwater extraction shifted the Earth’s axis: What a new study says .... https://indianexpress.com/article/explained/explained-climate/groundwater-extraction-shifted-earths-axis-study-8692912/.

(6) Humans pump so much groundwater that Earth’s axis has shifted ... - CNN. https://www.cnn.com/2023/06/26/world/pumping-groundwater-earth-axis-shifting-scn/index.html.

FAQ's

What does it mean when the earth shifts its axis?

Daily changes in light and temperature are caused by the rotation of the Earth, and seasonal changes are caused by the tilt of the Earth.

What would happen if Earth's axis shifted?

According to Business Insider, Earth spins at an angle of around 23.5 degrees; if that axial tilt were to change enough to spin sideways on its axis, whole portions of the planet could be plunged into darkness or thrown into direct sunlight for months at a time.

When did the earth shifted on its axis?

1990s In the 1990s, the Earth's axis underwent a major shift. It is normal for the Earth's axis to move by a few centimeters each year. But, in the 1990s, the direction of polar drift shifted suddenly and the rate of the drift accelerated.

What is groundwater extraction also called?

This is sometimes called “mining” of groundwater. As pumping continues, groundwater recharge and discharge adjust to lower groundwater levels until a new equilibrium is reached and water levels stabilize (or the aquifer is completely exhausted if pumping exceeds total recharge).