This seems really, really absurd: Humanity has extracted so much water from underground that our axis of rotation has started to tilt. To summarize: our insatiable “thirst” (over 2 trillion tons between 1993 and 2010) has moved the geographic North Pole by 4.36 centimeters per year.
Small changes, big changes
As a rule, the axis of rotation of celestial bodies tends to be stable. However, when large masses move within a planet and on its surface, so to speak, "variations" can occur.
As he states Ki-Weon Seo, a geophysicist from Seoul National University, “Any mass moving on the Earth's surface can change the axis of rotation”
Astronomers track these changes in the Earth's axis by observing quasars, the bright centers of distant galaxies that are virtually immobile landmarks. The largest change in the axis is seasonal, triggered by the movement of atmospheric masses as the seasons and climate change. This effect causes the Earth's geographic poles to “swing” by several meters every year.
Hidden water makes a difference in the Earth's rotation axis
The movements of water masses can cause smaller, but still measurable, variations in the inclination of the Earth's axis. Until recently, researchers thought these effects were mainly due to melting glaciers and polar ice caps. But when Seo and his collaborators tried to model Earth's water content to explain how much the axis had tilted, they couldn't fully explain the data.
Gravimetric investigations have measured the emptying of underground tanks, caused largely by irrigation, especially in northwestern India and North America. These studies show that groundwater pumping moved enough mass into the oceans to cause global sea levels to rise by 6.24 millimeters between 1993 and 2010.
By including these variations in their model, the authors calculated their impact on the Earth's rotation axis (in a study that I link to here). They predicted that groundwater extraction alone causes the North Pole to move 4.36 centimeters per year, more or less in the direction of Russia's Novaya Zemlya Islands.
The dancing planet
We live in a world that (also) dances to the rhythm of our water consumption. Our planet is a sensitive dancer, whose steps change in response to our behaviors.
A silent and imperceptible dance, but which we must take into account.
After all, how could we ignore the fact that our actions even affect the axis of rotation of our planet? There is no better way to understand that all of us humans have our feet in one pair of shoes.
