Humans are pumping out so much groundwater that it's changing Earth's tilt

News
By
published

And it could even affect climate.

The Earth's tilt has changed because of the amount of groundwater pumped by humans.
Scientists discovered that Earth's tilt has changed because of the amount of ground water pumped by humans. (Image credit: Seo et al.)

Earth's tilt has changed by 31.5 inches (80 centimeters) between 1993 and 2010 because of the amount of  groundwater humans have pumped from the planet's interior. 

In that period, humans removed 2,150 gigatons of water from natural reservoirs in the planet's crust. If such an amount was poured into the global ocean, its surface would rise by 0.24 inches (6 millimeters). A new study has now revealed that displacing such an enormous amount of water has had an effect on the axis around which the planet spins. 

Scientists arrived at this conclusion by modeling the changes in the position of Earth's rotational pole, the point at which the planet's imaginary axis would stick out of the surface if it were a physical object. The position of the rotational pole is not identical with the geographical north and south poles and actually changes over time, so the rotational axis cuts through different spots on the planet's crust at various points in time. 

Related: Climate change has altered the Earth's tilt

Since 2016, scientists have known that the rotational pole is affected by climate-related processes, such as the thawing of icebergs and the redistribution of the mass of the water locked in them. But until the researchers added the pumped-out water into their models, the results hadn't perfectly matched observations. Without the pumped-out groundwater, the model was off by 31 inches (78.5 centimeters).

"Earth's rotational pole actually changes a lot," Ki-Weon Seo, a geophysicist at Seoul National University who led the study, said in a statement. "Our study shows that among climate-related causes, the redistribution of groundwater actually has the largest impact on the drift of the rotational pole."

Since the tilt of Earth's axis can have an effect on seasonal weather on the planet's surface, scientists now wonder whether the shifts of the rotational pole could contribute to climate change in the long-term. 

Related stories:

— Milankovitch cycles: What are they and how do they affect Earth?
— How fast is Earth moving?
— How Earth's orbit shaped the Sahara

"Observing changes in Earth's rotational pole is useful for understanding continent-scale water storage variations," Seo said. "Polar motion data are available from as early as the late 19th century. So, we can potentially use those data to understand continental water storage variations during the last 100 years. Were there any hydrological regime changes resulting from the warming climate? Polar motion could hold the answer."

Overall, the Earth's rotational pole shifts by several meters a year. How much drained groundwater reservoirs contribute to this shift depends on where on the planet they are located. The study showed that water removed from mid-latitudes has the largest effect on the planet's tilt.

Managing how groundwater moves around the globe could therefore help limit the shifts of the rotational pole and thus the potential climate effects that come with them. 

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community@space.com.

Tereza Pultarova
Tereza Pultarova
Senior Writer

Tereza is a London-based science and technology journalist, aspiring fiction writer and amateur gymnast. Originally from Prague, the Czech Republic, she spent the first seven years of her career working as a reporter, script-writer and presenter for various TV programmes of the Czech Public Service Television. She later took a career break to pursue further education and added a Master's in Science from the International Space University, France, to her Bachelor's in Journalism and Master's in Cultural Anthropology from Prague's Charles University. She worked as a reporter at the Engineering and Technology magazine, freelanced for a range of publications including Live Science, Space.com, Professional Engineering, Via Satellite and Space News and served as a maternity cover science editor at the European Space Agency.

4 Comments Comment from the forums
  • George²
    Well this scientists are make gigatons of BS. Change my mind! :)
    Reply
  • volleyballjerry
    This is probably the stupidest article on this subject I have yet seen in the area of human caused catastrophe.

    So let's get right to the point. Tereza and her scientist friends are opposed to all modern human activity. Our very existence on this planet damages their god which is "Mother Earth". So whether it is carbon emissions or electricity usage or (now) water pumping? But I do not see any of these hypocrites volunteering to end their lives in order to help save the planet!

    None of their claims are even measurable to prove anything beyond their sacred "mathematical models" . Let me tell you all something. I use advanced mathematics in my job daily doing orbital analysis. I possess two engineering degrees and am a licensed professional engineer in Colorado and Texas. You can use "mathematical models" to say whatever you want.

    There are *zero* instruments anywhere that can measure a change in axial tilt of 0.8 meters on a planetary body with a circumference of 40,000,000 meters! Furthermore, any such tilt even if detectable would be impossible to ascertain cause. Our best instruments today astronomically can measure the obliquity of the Earth to 0.01 degrees. That is it! Not tens of thousandths of degrees.

    Additionally, every single drop that ends up in the oceans falls back to land as fresh water in the form of rain. One thing these stupid fools probably did not consider is that the amount of rainfall dwarfs human activity.

    The Earth, worldwide, receives on average approximately 39 inches of rain per year. With a surface area of 196,900,000 square miles that equates to 1.784 x 10^16 cubic feet of rain annually. Convert that to weight (62.4 lbs. per cubic foot of water) you have 5.56610 x 10^14 tons or 556,610 Gigatons of rain falling on the earth each year.

    The article claims that because 2150 Gigatons of water has been pumped from reservoirs in the last thirty years, the Earth’s axial tilt has shifted. In the last that thirty years, 16,698,319 Gigatons of rain has fallen on the earth. That is 7767 times the amount of water pumped! So, no. Human activity is not causing any shift in the tilt of the earth. There is no evidence that any shift in the tilt of the earth is occurring AND there is no reliable model that predicts what the effects on climate would be anyway. If the shift is *reduced*, it actually would stabilize the climate. Yet Tereza makes no mention which direction the shift is occurring (likely because all of their data is made up anyway).

    This is an effort to create another false crisis to justify authoritarian rule against capitalism and industry. Nothing more. The next thing we will start hearing about is "sea level justice" because an ocean that rises half of one centimeter disproportionately impacts the poor. The problem with that is that the most expensive real estate anywhere in the world is oceanfront property. *RICH* people lose their beachfront homes first.

    "Tereza is a London-based science and technology journalist, aspiring fiction writer and amateur gymnast. "

    She should work on her career as an aspiring fiction writer. And stay away from anything regarding scientific fact.
    Reply
  • Unclear Engineer
    Well, it is probably not any sort of problem for us if the water we pumped out of aquifers does slightly alter the rate of precession of our rotational axis, or even the location of the magnetic north pole. The problem is that we are going to run out of groundwater to pump in several areas where that has become an important part of agricultural production.

    That said, I am willing to believe that the amount of standing water reduction in aquifers, along with the loss of glaciers and mass in polar ice caps, can make miniscule changes in the rate of precession of our rotational axis. I have long suspected that the build-up and melting of the huge ice sheets, mainly in the northern hemisphere, probably altered the precession rate much more significantly, since the water came mainly from equatorial ocean areas (about 325 feet of depth) and piled up on northern temperate and arctic areas (to depths of 1-to-2 miles). That should affect the rate of precession and even the length of the day, as mass is moved to different radii of rotation.

    This effect might be needed in the climate models to get their ice age periods to more accurately line-up with the Milankovitch Cycles, since it actually changes the periods of some of those cycles.

    But, it is not a simple calculation as if the Earth is a ridged rock. We know that the ice sheets cause the shape of the rock/soil surface of the Earth to change, getting closer to the center under the ice and bulging up elsewhere. So, that partially compensates for the ice buildup. But, because the melting was so fast from about 25,000 years ago to about 15,000 years ago, the Earth's shape has not changed back to its ice-sheet-free shape, yet. Where I live now, the land surface is still sinking about 1 foot per century.

    So, while not a reason to panic, the results of the study are still interesting with respect to learning about climate effects over long periods.
    Reply
  • bearwill
    Big oil & chemical Disinformation, more of their tripe down the pipe.
    Its crude oil, the tilt towards Siberia, Russia, Magnetic North has moved like 30 - 40 miles, that would make Saudi Arabia's side light now & causing the tilt towards Russia.

    Professor is right about the precipitation & replenishment of aquifers, but nobody is blowing oil back into wells. When they should be forced to take all of their toxic plastic that they don't or won't recycle, melt it & pump it back down whence it came. Murders look like hero's & peon's can collect & turn in the toxic plastic.
    Reply