Humans have pumped enough groundwater to change the tilt of the Earth

2 years ago (e360.yale.edu)

FFS is it to much to ask for a primary source?

Drift of Earth's Pole Confirms Groundwater Depletion as a Significant Contributor to Global Sea Level Rise 1993–2010

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/202...

or even the official press release?

https://news.agu.org/press-release/weve-pumped-so-much-groun...

  • Well yeah... but the linked page is 1.59Kb in size and if you visit the heavier version of the page at: https://e360.yale.edu/digest/groundwater-depletion-earths-ax... it includes your links in the HTML and a third link about past discussion.

    • The original URL for this was woeful, while it did link to your link above and via that to Geophysical Research Letters it still makes more sense to directly link to the actual primary source, either the ELI5 AGU press release or the actual paper in GRL.

      HN has a technical audience that appreciates primary sources.

      4 replies →

2 trillion tons = 1/3 of 1 billionth of the mass of the earth. the distance from the ground to the surface is around 5 millionths of the radius of earth (like 100ft)

So you're talking about a change in angular momentum that is on the order of 10^(-20) times the angular momentum of earth (mr^2 \omega).

A change in the pole of earths rotation by 31 inches (10^(-7) times the radius of earch) corresponds to a change in angular momentum on the order of 10^(-14). So we seem to be off by 7 orders of magnitude.

I call bullshit.

  • Your computation is very wrong, as explained in the actual research paper and in another comment here. The water is not moved only from under the ground to the surface and the effect on the axis is not due to raising, but mainly to horizontal movement.

  • > the distance from the ground to the surface is around 5 millionths

    The water from aquifers is not just lifted a short distance up to the surface. It is used, ends up in rivers, and spreads around the world's oceans. And the places where we are pumping groundwater are not uniformly distributed around the Earth. We are essentially moving mass to the Pacific.

  • Yeah I don’t know that this even makes sense at a glance. How much mass do we expect just moves around by natural processes? Should we even expect to be able to detect an effect of this magnitude (as in, distinguish it from noise)? I do not think so:

    - Based on a cursory search, a large iceberg may weigh in at ~1 trillion tons. The calving process moves mass hundreds of kilometers away from Antarctica. This should be an effect of similar magnitude!

    - The water cycle moves ~500 trillion tons of water each year. This water is moved hundreds of kilometers and isn’t evenly distributed over the course of a year. We should expect the impact of seasonal fluctuations in water distribution to thus have a comparatively much larger impact on the earth’s rotation.

    I don’t think these numbers add up. I think we’re reading this story because it feeds into a certain kind of “we are hurting Mother Earth” mindset.

    • The largest iceberg ever measured, B-15, had a mass of about three billion tons. Still enormous, but not trillions, which sounded unbelievable enough to prompt me to look.

      1 reply →

    • The calving process results in ice already floating in water moving. Archimedes' law means the effect is very limited ~ the height the ice sticks above the surface and the little change in density.

      More importantly, the article mentions removing annual effects on Polar Motion. They are averaging - somehow - to look at permanent changes. The annual effects may be an order of magnitude greater, it is not relevant.

  • So we want to calculate the change in momentum caused by moving water from just under the surface to the surface.

    Assume earth is a perfect sphere, let m be the mass of earth and r be the radius of earth. Let rdm be the relative mass of the water moved = 3e-8, let rdr be the relative distance of the water moved = 5e-6.

    The change in momentum is rdm.m.(1+rdr)².r² - rdm.m.1².r² which is 2.rdm.rdr.m.r²= 3e-14mr². Looks about right for the change of axis you wanted.

    There's other counter arguments but at least the oom analysis fits.

  • This sounds truthy to me. Can anyone confirm, and also weigh in on whether uneven distribution of the moved mass might account for any of the missing orders of magnitude?

    • Uneven distribution is the entire effect.

      Groundwater is mostly under ground... And the center of mass of all the surface crust is hundreds of kilometres from the center of mass of all the world's oceans.

  • Scientists and researchers collect two decades worth of data and publish peer reviewed papers.

    Genius HNer looks as the title, spouts some factually incorrect data to "debunk" it and gets upvoted to the top.

    Sadly I'm not just describing this instance but internet discource in general. Critical thinking and analysis is dead in the age of "gotcha" hot takes.

    • ironically this comment is annoying and pointless cynicism and meta commentary while the original comment is interesting, although apparently wrong - your response should be deadlast but unfortunately I see it before the other comments explaining where in the paper to find why this reasoning is wrong...

    • This seems to happen a lot here lately, particularly on earth and space science related topics. After you read the comments on a paper in your field, it becomes depressingly obvious that a lot of the most upvoted commentary is armchair skeptics doing back of the napkin math that sounds good but falls apart upon closer inspection. Gell-mann amnesia effect, etc.

      1 reply →

    • for the record, nothing in the paper makes me feel better about the issue I raised.

  • Even from a “sniff test” perspective, this seems highly suspicious.

    • - water is heavy

      - pumped water gets used and flows to the oceans, far away

      - we have pumped a lot of water (look up how much some places have subsided due to groundwater depletion).

      - the earth's rotation is something we've worked out how to measure very, very precisely

      It sounds completely plausible to me.

    • Totally. Prima facie bullshit. Problem is that the "I F@#$king Love Science" crowd doesn't actually know how anything about science or math, so they'll buy pretty much anything backed up by even low-quality technobabble.

      4 replies →

By modelling the previous location of groundwater (under the ground), and the new location of groundwater (on the surface of the ocean) one can calculate the change in the earths rotational axis that is expected. The measured change matches predictions only if this effect is considered.

The location changes the axis because most land is on one side of the earth (centered around Europe), and most ocean is on the other side (centered around the south Pacific). Move mass from one place to another, and the axis changes.

I am not saying the premise is BS, but like all engineering and science you create a hypothesis for a phenomenon, in this case the pole shift, to address it, and you create the formulas and parameters to be included and used. As others have pointed out, there are potentially a lot of other variables to be considered that they possibly did not include. To further test the hypothesis, they need to sharpen their pencils for round two or three. Some off the top of my head: if there are higher drought areas or more wetter areas due to climate change, did they consider that shift? Location, position, and magnitude of snow-melt basins, glacial melt and polar cap changes, earth moving human activities on scale by all nations (China making artificial islands, etc.), earth moving due to climate change - floods, drought, large volcanic eruptions, underwater tectonic activity - all an ongoing process), etc...

The father/scientist of the article should not put his pencil down just yet. Very interesting hypothesis so far.

I've always wondered, once we get into asteroid mining, whether there will be a global "massening" if we bring more matter back to the planet. If the orbit should change and you know, cause problems and whatnot.

  • That’s a hilarious idea. It wouldn’t surprise me if we did that. Find 1b tons of gold somewhere and start building houses out of it on earth

    • In medievil times Alchemy was the search for changing base metals (mostly lead) into gold. Clearly unimaginable riches would follow.

      What they didn't realise was that turning lead into gold does not make lead as valuable as gold. It makes gold as valuable as lead.

      This has happened before. Aluminium used to cost more than silver. The Washington Memorial is capped in aluminium for all of about 9 inches high, at fantastic cost.

      Development of the Hall process made aluminium plentiful. It's now a cheap house-hold item we discard daily.

      If we found a billion tons of gold, the value of gold would crater basically to the cost of actually bringing it to earth. We'd find uses for it (its pretty) but it'd make a terrible building material :)

      17 replies →

  • Hmm, Earth is losing 60000 tons of atmosphere per year. And this has been going for quite a while. Bringing back stuff might not be great effect.

  • The mass of the Earth has no impact on its orbit. Think about it this way: the northern and southern halves of Earth orbits the sun in exactly the same orbit as the full Earth. Now, if we increased the mass of the Sun, however…

Even 2 trillion tonnes sounds like a very small amount of water compared to what must be getting redistributed by climate change? The Antarctic ice sheet alone weighs around 25,000 trillion tonnes. So even just melting 0.1% (25 trillion tonnes) of it would move far more water into the oceans than we've ever pumped from groundwater!

Technically any time someone pumps groundwater it changes the tilt of the earth unless other things coincidentally happen to cancel it out.

I was about to make some joke about how this explained climate changed and meant we, in the end, need not worry about greenhouse gases.

But then I tried to look up what the actual impact of our planet’s tilt slightly shifting could be.

While I could not come up with anything meaningful, it appears glaciers melting also contributes to this [1].

[1]: https://www.theguardian.com/environment/2021/apr/23/climate-...

  • From the press release linked in a comment above:

    >The rotational pole normally changes by several meters within about a year, so changes due to groundwater pumping don’t run the risk of shifting seasons. But on geologic time scales, polar drift can have an impact on climate, Adhikari said.

  • Any siginificant movement of mass, particularly mass far from the axis of rotation, changes the dynamic balance and induces pole shift.

That's nothing compared to the interglacial-glacial 100,000 year cycle that set in since the Pliocene Era (c. 3-5mya). Current activity is kind of interesting though, accelerated time-frame-wise:

https://www.smithsonianmag.com/science-nature/melting-glacie...

> "At the same time, there are a lot of new salmon streams opening up in Glacier Bay, says Eran Hood, professor of environmental science at the University of Alaska. “As glaciers are melting and receding, the land cover is changing rapidly,” he says. “A lot of new areas becoming forested. As the ice recedes, salmon is recolonizing. It’s not good or bad, just different."

Human activity has become the dominant feature in most if not all ecosystems on Planet Earth, that's just the reality. The trigger has been pulled, welcome to the now.

> "As our gargantuan glaciers melted, the continents up north lost weight quickly, causing a rapid redistribution of weight. Recent research from NASA scientists show that this causes a phenomenon called “true polar wander” where the lopsided distribution of weight on the Earth causes the planet to tilt on its axis until it finds its balance. Our north and south poles are moving towards the landmasses that are shrinking the fastest as the Earth’s center of rotation shifts. Previously, the North Pole was drifting towards Canada; but since 2000, it’s been drifting towards the U.K. and Europe at about four inches per year."

So, I guess if we have a 31 inches over 17 years change via groundwater pumping, then we have 80 inches over 16 years due to glacial melt... how do they sort all that out? Did they even take the glacial factor into account?

Yesterday I had water in DC. A five hour drive with no stops later, I relieved my self.

I changed the tilt of the Earth.

Are our instruments sensitive to measure this? No.

Are our insanely accurate instruments able to measure other human activity? Yes.

Is the tilt change significant? Not at all.

Is ground water exploitation a problem? It is a massive problem, and one that doesn't need FUD distractions.

  • The article reads like the opposite to FUD because it's dry. Instead it's more like 'People previously estimated how much groundwater was pumped to the sea. If it is that much earth's axis should tilt like this. We checked, it does. It is actually the second biggest variable to explain permanent axis drift.'

    It's not a distraction, it is confirmation. In the future we can confirm groundwater pumping estimations by looking at axis tilt and it becomes harder to deny it happening.

    EDIT: Reread the abstract. The previous estimations did not have direct evidence, this is such evidence.

Would it kill them to add 10 bytes of css to make it readable on mobile?

EDIT - was talking about 68k news link before it was changed.

Better title: Yale scientists have improved geomeasurement until they could detect minute changes in axial tilt.

In the next Austin Powers movie, Dr Evil will try to accumulate so much mass in one place that earth flies off its orbit.

I’m not sure if I’m supposed to panic more because we’re tilting the earth, or panic less because we’re melting less ice than we thought. Or panic the same because the jury is still out in this research.

  • Is this some kind of anti humanity to think that every generation fucks up the earth in their way and increasingly and if that means the humanity ceases to exist that’s okay, because either I won’t be alive by then or if it happens in my time then eventually I die anyway and there’s nothing after that? So that’s fine. I mean let’s try to fix it, if not just fuck it and stop fretting over it. Let’s get done with either way.

  • All this panic is not productive and besides, climate predictions seem to change every few decennia.

This seems right up their getting all Americans to jump off a two foot high chair at the same moment to alter the planet’s spin and orbit

Next we will go from reducing carbon to reducing water usage based on another popular junk science theory.

  • Excess groundwater extraction already causes numerous issue across the globe without considering a small effect on the Earth's tilt. Surely you don't need to accept any of the climate change science to accept that making the world a better place, doing less harm and using limited resources at a slower rate is a good thing. That's just simple thoughtfulness, common sense and good planning (all things humans are often terrible at).

[dupe]

  • Yes. We are mining water. While notionally replenishable, we are withdrawing from the water table in many areas (I'm familiar with California) so much faster than the replenishment rate that the aquifer is collapsing, meaning it will never be able to hold the water it used to anymore.

  • Yes. But it depends on the aquifer. For example the Edwards Aquifer in Texas gets recharged from rainfall. But the Ogallala Aquifer supplies water at least 10,000 years old and rain doesn't affect it. Once we pump the Ogallala dry it will stay dry.

  • We pump it up by the megatonne over decades, we spray it outwards for crops or to water animals.

    Some travels back down through the soil, most either evaporates or is taken up by plant matter, sweat out, goes to meat, etc. - which results in movement of the water mass to elsewhere on the planet.

  • Groundwater reservoirs have a recharge rate. That is the rate that surface, or I suppose even deeper, water is sequestered in the layer in question. We are extracting faster than that recharge rate.

  • I have no idea, but:

    Groundwater naturally is somewhat steady state. You get rain, it filters through and then there is spring or something somewhere and goes back to cycle in river or evaporation. Part of the cycle.

    Now if you remove more water than exit through the natural processes you move it out from groundwater table. Thus creating imbalance and changing the steady state.

  • There are many ways to recharge the ground water. One is filling up dedicated basins periodically and letting the water trickle down. These basins are managed regularly to allow the water to percolate. Rivers also help with ground water recharge but only within their watersheds and routes. Also, Newsom in California recently issued an executive order to use flood water from recent rains for ground water recharge. https://www.gov.ca.gov/wp-content/uploads/2023/03/Refilling-...

  • Mining and trapping groundwater in billions of tonnes in sugary soft drinks which then sits in supermarkets maybe?

I don't believe their figures.

But if we had of removed that amount of mass you'd expect the continent to rise. Maybe it's fuck all, still want to know the figure -

https://en.wikipedia.org/wiki/Post-glacial_rebound

and obviously the greatest source of land loss is ground water depletion near the sea. We need to replenish aquifers even if studies like these are just made up. And heck we could even raise our land near the sea rather than messing with dikes.

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  • The end is inevitable, we should try our best and see what happens, but thinking that the root of issues is over-population is false,

  • unintentionally terraforming? what is the definition you're using for terraform?

    terraform: (science fiction) To transform the atmosphere (or biosphere) of another planet into one having the characteristics of Earth.

    https://en.wiktionary.org/wiki/terraform

    since we live on Terra, it has always had by definition terra-form, but if you use it to mean "make it support more humans inasmuch as we think we know how to do that", are you saying we're making it better or worse, unintentionally?

    or are you just using it to mean "making planet-scale changes"?