Context:

A recent study revealed that excessive groundwater pumping over the time of less than two decades has caused Earth to tilt by 31.5 inches.

More on the news

• A study published in the journal Geophysical Research Letters found that large-scale extraction of groundwater has shifted Earth’s rotational pole. 
• This motion of the Earth's rotation pole is known as polar motion. 

Key findings of the study

Groundwater pumped from various regions flows into the oceans and alters the distribution of mass on the planet, influencing the tilt and rotation of Earth.

• Similar to how adding weight to a spinning top changes its motion

Significant water movement from regions like western North America and northwestern India is a key driver.

The pumping of groundwater caused the Earth to tilt 31.5 inches over 17 years, or about 1.8 inches per year.

This redistribution of water has also contributed approximately 0.24 inches to sea-level rise.

Significance of the study

• Earth's rotational pole changes frequently. The study shows that among climate-related causes, the redistribution of groundwater has the largest impact on this process.
• Scientists know that the movement of water can influence Earth’s rotation, but this study quantifies the effect.
• Shows pumping groundwater is another source of sea-level rise. 
• Changes in Earth’s rotational pole can be used to understand continent-scale water storage variations.
• Monitoring Earth’s tilt can help us track how groundwater movement influences climate and guide conservation efforts to address rising sea levels and other climate challenges. 

Groundwater extraction

• Groundwater accumulates in aquifers and serves as a critical resource for drinking water, agriculture, and industrial processes.
• It is depleting at an alarming rate. Between 1993 and 2010, humans pumped an estimated 2,150 gigatons of groundwater, much of which ended up in the oceans.
• Excess extraction causes lowering of water table, land subsidence, saltwater intrusion, etc.