Earth Has Tilted 31.5 Inches. That Shouldn't Happen

(popularmechanics.com)

128 points | by dataflow 12 hours ago ago

82 comments

  • x______________ 12 hours ago ago

    Clickbait title.

    Link to the original study:

    https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023GL10...

      Drift of Earth's Pole Confirms Groundwater Depletion as a Significant Contributor to Global Sea Level Rise 1993–2010
    • throwaway150 11 hours ago ago

      > https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023GL10...

      Any chance the original link can be replaced with this? This is definitely way more informative than the clickbait article.

    • panarchy 11 hours ago ago

      But this implies it could be the fault of human influence. Humans are incapable of making any sort of change to the planet! That would be inconvenient.

      • mr_toad 8 hours ago ago

        Don’t look down!

        • panarchy 8 hours ago ago

          But that's where all the sand is to put my head into!

        • ForOldHack 8 hours ago ago

          Down? Or down under?

    • ForOldHack 8 hours ago ago

      To everyone to posts links to the source material: THANK YOU SO MUCH! Thank you.

    • shvdle 12 hours ago ago

      [flagged]

      • perching_aix 11 hours ago ago

        I understand that this is ragebait, but even then, these are not mutually exclusive claims. There being a significant contributor doesn't mean it was the dominant contributor, and you being told things by some people doesn't mean you're choosing your sources well / the same as others.

        Mutual exclusivity not applying so much so, that the article you're commenting on downright puts these events into the following hierarchy: groundwater pumping -> climate change -> sea level change. So it'd be a subset of the total effect of it on a theoretical pie chart: literally no conflict in the rhetoric.

      • kubb 11 hours ago ago

        Sigh. You made an account for this?

        Do you know what a contributor is?

        I understand if someone with cognitive issues buys into demonstrable fact denial, but hackers usually are way above that level.

        • asacrowflies 8 hours ago ago

          The amount of fact denial and anti science comments on this site are much higher than reddit or others honestly.... Just has moderation to not allow shitposts and gifs and such but it is still very eloquent science illiteracy.

        • shvdle 11 hours ago ago

          [flagged]

          • righthand 11 hours ago ago

            Global warming already has multiple contributors…so always.

      • oh_nice_marmot 11 hours ago ago

        The melting of ice caps, glaciers and others make no difference then.

  • 0hijinks 12 hours ago ago

    >> ...we can see that, in less than two decades, Earth has tilted 31.5 inches as a result of pumping groundwater. This equates to .24 inches of sea level rise.

    For those confused how they managed that geometric analysis, the sea level rise mentioned in the paper [1] is caused by groundwater depletion. The tilt is caused by groundwater depletion. The sea level rise is not caused by the tilt.

    [1] https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023GL10...

    • martinpw 11 hours ago ago

      Figure 1 in the above paper packs a lot of interesting information: https://agupubs.onlinelibrary.wiley.com/cms/asset/d7c477fa-3...

      One important factor shown there is that dams hold back water on land, so act to decrease sea levels. It is not as big an effect as groundwater depletion, but is significant (around half as much).

      The net effect of these two is much less than the other factors causing sea level rise (melting land ice) - looks like around 10% of total sea level rise comes from groundwater depletion+dams combined.

      • metalman 5 hours ago ago

        here's the problem with dams filling up and offseting ocean rise, amost all of the potential large dams, have been built and are full now, and that offset has masked some ocean rise, which is now accelerating, but all of the "planning" ,climate mitigation policy, treatys, etcerlalala, has been working with the wrong numbers. the wild card is changes in salinity and temperature shutting down the main thermo transfer currents at each pole, setting off deap ocean warming and expansion. not good.

    • chongli 11 hours ago ago

      Not to mention that inches are not a measure of angle, they’re a measure of length. I would prefer a proper measure of angle such as arcseconds. With some dirty math (taking 31.5 inches as an arc segment of earth’s polar circumference) yields a tilt of roughly 4 milliarcseconds, an extremely small angle to say the least.

      • jacobolus 10 hours ago ago

        An arcsecond is 1/60 of an arcminute; an arcminute is 1/60 of a degree (°); a degree is 1/360 of a full turn. A "milliarcsecond" is probably an unfamiliar unit (an angle so slight will only be used in extremely specialized contexts), so if you like you could decimalize this to an angle of 0.000001°.

        The measure of distance on earth is probably more easily comprehended by almost everyone though.

        • dotancohen 8 hours ago ago

            > The measure of distance on earth is probably more easily comprehended by almost everyone though.
          
          The measurement itself is useless without knowing the size of the Earth, which very few people know offhand. That said, 30 inches sounds like something tangible, and that's the important information here. That human activity had a measurable, tangible effect on the Earth.
        • ForOldHack 7 hours ago ago

          Although I hate/detest using AI, I asked Google to calculate it...

          0.0000072 degrees is 25.92 milliarcsecond.

          Assuming that the Earth is a perfect sphere, which it is not, so now...

          I have to burn up some Mathematica time, and have it calculated in elliptical coordinates.

      • undefined 7 hours ago ago
        [deleted]
      • skeledrew 10 hours ago ago

        I, and I suspect many others, have no clue what an arcsecond is and thus it's significance in anything. Inches also doesn't really give accurate significance, but at least it's relatable and doesn't leave me 100% lost, and I can focus on the message that something significant has been discovered, which may require some action.

        • SoftTalker 10 hours ago ago

          I think it's pretty apparent that ~1 yard, i.e. about one step at a typical walking stride, is tiny relative to the circumference of the earth. I agree that it's a more understandable measure for most people than "arcseconds"

        • grg0 9 hours ago ago

          What happened to degrees or radians?

          • fiddlerwoaroof 8 hours ago ago

            A degree is too big for the effect, the division of the degree into 60 arcminutes and the arcminute into 60 arcseconds is the standard subdivision of degrees as an angle measurement going back to the Sumerians.

          • skeledrew 7 hours ago ago

            Still doesn't say much to many. Temperature will be what comes to mind first for the lay person when they hear "degree", blank stare for "radian". But pretty much everyone in the US knows what an "inch" is, and the rest of the world can do a quick lookup/conversion. And everyone knows immediately on seeing the headline that something moved from its usual spot to somewhere else.

          • ForOldHack 6 hours ago ago

            Again... AI blows, but ...

            "Calculate the fraction of the circumference represented by the arc segment:Divide the arc segment length by the Earth's polar circumference (in inches):31.5 inches / 1,574,896,558.4 inches = 0.0000000200012759 Radians.

            Which is kinda interesting, as it calculates the earths' circumference in Inches. 1.57 Billion inches.

      • rayiner 9 hours ago ago

        Sigh. This is why I read the comments. Thank you.

    • stouset 11 hours ago ago

      So just to clarify, what you’re saying is that the volume of water we’ve pumped is directly responsible for the observed sea level rise? The article makes it sound as if the tilt is what was responsible, and I was curious about the mechanics of that.

  • SoftTalker 11 hours ago ago

    Why shouldn't it happen?

    I would guess that when there were gigatons of frozen water where there now is none that also changed the rotation of the earth.

    Large magma flows and volcanic eruptions also change the rotation.

    The earth is not a static system.

    • bbuut 11 hours ago ago

      To most people it is a static system as they live life based on the Gregorian calendar, and that loop, and never look into the dynamism in nature.

      Headlines like this are not intended to be hard science.

      They’re intended to connect to most people’s beliefs. Usually they explain away the knee jerk false beliefs.

    • eastbound 11 hours ago ago

      There is also a theory that the gravity made by the icecaps attracts water north and south. After melting, Sweden would see the water go down by 8 meters, the median point would be the south of England, and oceans would rise twice more around the equator.

      • OJFord 11 hours ago ago

        As we've already observed sea level rising, wouldn't we have also already observed it falling in Sweden (and rising faster around the equator) if that were the case?

        • pixl97 10 hours ago ago

          Well you also have to take isostatic rebound into account when attempting to calculate this as the crust where the glaciers were is still rising.

          https://www.antarcticglaciers.org/glaciers-and-climate/sea-l...

        • eastbound 9 hours ago ago

          We absolutely have. Remember NYC was supposed to be underwater by 2000. That’s probably because of counter forces like this one. This, or the prediction was a scientific mistake. They happen, too.

  • nothrowaways 11 hours ago ago

    > Planet Earth Has Tilted 31.5 Inches

    How much would that be in degrees?

    • throwaway_95283 10 hours ago ago

      0.00000718742 degrees = 31.5 inches / 40,075 km * 360 or 0.000451599142 arcseconds obviously its not very much,

      • ForOldHack 6 hours ago ago

        Can you check your units? in/km? 31.5" is almost exactly 0.8m

  • droopybuns 10 hours ago ago

    Cargo cultist stem aficionados write sentences like “Can we fix it back?”

    • owenversteeg 6 hours ago ago

      Obviously we can, global groundwater depletion is very hard to estimate but estimates range from 20-300 km3/year (this paper uses a figure of 126.) Global desalination production is around 35 km3/year and growing rapidly.

      1km3 water =1 gigaton = 1B m3 water.

  • thayne 10 hours ago ago

    > I’m concerned and surprised to see that pumping groundwater is another source of sea-level rise

    How is that surprising? It seems pretty obvious to me that pumping groundwater would accelerate how quickly that water ends up in the ocean, and could thus lead to rising sea levels.

  • rNULLED 7 hours ago ago

    i myself personally must untilt the world 31.5 inches

    • readthenotes1 6 hours ago ago

      Glueing yourself to a heavily traveled road should do it

  • csense 8 hours ago ago

    Start with a spinning sphere with a known axis / rate of rotation and some bit of mass on its surface that you can move. You can move it in three directions, let's call them latitude, longitude and altitude [1]. The classic examples I learned in physics class are about altitude (e.g. figure skater spinning faster when she brings her arms inward) which alters the magnitude of angular velocity (assuming conservation of angular momentum).

    My intuition is that, if changing the altitude only affects the magnitude of the angular velocity, the other 2 degrees of freedom (longitude and altitude) must determine the direction of the angular velocity.

    You start with a model of mass distribution of Earth over time, let us say M(x, y, z, t). Let us call w(t) the Earth's angular velocity at time t. If you know w(t_0) for some time t_0, you can calculate what the model says w(t) will be. The givens are: M(x, y, z, t_0), M(x, y, z, t), w(t_0), and conservation of angular momentum. You want to calculate w(t) from the model, then compare that calculation to the measurement to test the model. Your hypothesis is the model is accurate; your experiment is comparing the model's prediction of w(t) against the measured w(t).

    I'm immensely curious to know how M(x, y, z, t) is calculated. They show some satellite images but it seems like they would only measure lakes, rivers, and maybe surface level soil saturation. But to me "groundwater" implies things like aquifers and underground storage, how do they measure that? You'd need to not only know the amount of water but also its change in latitude and longitude. Do you assume that if groundwater is used it ends up in the oceans? That seems a bit presumptuous, wouldn't a lot of it soak into the ground, get taken up by plants, find its way back down into an aquifer, etc.? Having water soak into the soil and become integrated into a plant is literally the point of watering crops, if we assume agricultural water ends up in the ocean doesn't that mean farmers are using too much water, which would be economically irrational because water is not free?

    For that matter, why focus so much on water? Solid matter also has mass and we change its latitude, longitude and altitude when we mine it and turn it into products that we ship all over the world. For that matter, people and cars and ships and airplanes and wild animals all have mass and move around every day.

    I'm a bit lost trying to follow the paper, it says "Changes in terrestrial water and oceanic mass loads were converted to spherical harmonic (SH) coefficients of the geoid..." but I only have a vague notion of what spherical harmonics are, and I don't really understand the given formulas.

    [1] Latitude: Along the surface in the direction it's spinning. Longitude: Along the surface parallel to the axis of rotation. Altitude: Toward or away from the center of the sphere.

  • mvdtnz 10 hours ago ago

    How do you "tilt" in inches? A tilt is a rotation. I won't read an article with a headline that not only measures a tilt in the wrong type of unit but also opts for a medieval variant of a distance measure.

  • desireco42 10 hours ago ago

    All that K-Pop makes people jump too much

  • aaron695 11 hours ago ago

    [dead]

  • smitty1e 9 hours ago ago

    I, for one, appreciate the defiance of SI. #FightThePower

  • nothrowaways 11 hours ago ago

    This doesn't make sense, it's like taking a spoon full of water from a barrel. Shouldn't affect anything.

    • stouset 11 hours ago ago

      “This doesn’t make sense. We’ve only added 200ppm of CO2 to our atmosphere. Shouldn’t affect anything.”

      Systems at a roughly stable equilibrium can be surprisingly easy to shift out of that equilibrium by pushing them ever so slightly outside a local minima. Nobody right now is saying this particular situation is going to result in catastrophe, but we should exercise some caution when we are causing observable effects to the one planet we inhabit.

      • nothrowaways 7 hours ago ago

        I can bet the missiles and space rockets we launch have a higher effect to unbalance planet Earth's equilibrium.

        • stouset 2 hours ago ago

          I accept your bet. Please contact me and we can work out the details for your payment.

      • ForOldHack 4 hours ago ago

        The person who briefed me on the change in prediction of global climatic modeling, pushing the recovery back 75 years, also said this:

        "If you are in a flying 747 flying directly at another one, then it appears as a very very tiny spec in the sky, until you get close enough to see it, and then it gets really really big, really really fast, and then you are dead."

        He also said this about stable equilibrium: You can roll a glass in a circle on a table, and it can roll in a circle for a long time, but if it falls off the table, it is going to take some effort to get back to equilibrium.

        We have little idea what equilibrium is, and we also have less idea about what it will take to get back to it, after leaving it.

        See: "The Day After Tomorrow." (2004)

    • panarchy 11 hours ago ago

      This doesn't make sense I only applied 0.01n of force to this balanced inverted pendulum that took a whole 1n to get into place why did it fall over?

    • ceejayoz 11 hours ago ago

      It’s 31 inches in a planet that’s about 500 million inches wide. Would you notice that proportion of a change in a standard sized barrel?

      • ForOldHack 4 hours ago ago

        If you take a basketball, and breathe on it, the frost collected on it, is less than the thickness of the atmosphere. Many phenomenon are even less detectable, but see the prior comment about 747s.

        • ceejayoz 2 hours ago ago

          Yeah. Or parts-per-million of polonium in tea. Our ability to perceive it is different from our ability to be affected by it.

  • myflash13 11 hours ago ago

    So is it possible that Earth keeps “tilting” until the rotation direction is effectively reserved and the Sun rises from the west?

    • gpm 10 hours ago ago

      Conservation of angular momentum says no. Short of some giant external force acting on it (e.g. a collision with an exoplanet)

  • muzani 12 hours ago ago

    It always surprises me how millions of planets can move about predictably for millions of years. Unless it's hit with some gigantic rock... or it gets infected with sentient life.

    • AIPedant 11 hours ago ago

      I would not draw that conclusion from this article - we don't have such fine-grained data from other planets, perhaps their axes are more wobbly than Earth's. E.g it was only in 2020 that we discovered Mars has a "Chandler wobble" similar to Earth's (which was discovered 150 years earlier). But Mars's wobble is quite different as a matter of geophysics, Earth's Chandler wobble is mostly sustained by ocean sloshing. There's a whole lot we don't know about the non-Earth planets.

      I will add that human extraction of groundwater it not nearly as impactful as the formation of large igneous provinces and other ancient supervolcanoes. A tectonically active planet will definitely wobble unpredictably.

      • PartiallyTyped 11 hours ago ago

        We also found that our dams have slowed earth’s rotation!

    • furyofantares 11 hours ago ago

      > or it gets infected with sentient life.

      If only more planets could be so lucky.

      What value does a planet have without sentient life there to enjoy it?

      • ForOldHack 2 hours ago ago

        Sentient life: [ ] Venus [v] Earth [ ] Mars [ ] Uranus

        Value: [ ] Venus [v] Earth [ ] Mars [ ] Uranus

        None? I disagree, we should go back to arguing about sentient life on earth.

    • riku_iki 12 hours ago ago

      its survival bias, they were moving billions of years before, objects with unstable orbits traveled somewhere else, and stable objects formed stable planets.

    • positus 12 hours ago ago

      Humanity is not an infection. And how many of those millions of planets can you name?

    • ribcage 9 hours ago ago

      [dead]

  • mistermegabyte 11 hours ago ago

    The earth will be fine. I'm sure during the ice ages with gigatons of water trapped on the surface in glacial ice it would have had to changed the tilt also and the planet survived.

    The earth is such a large and variable system that over the long term, humans can't significantly permantly change something like weight distribution.

    • panarchy 11 hours ago ago

      Thank goodness the microbes will probably survive and maybe be able to try again in a few thousand to million years!

      • to11mtm 10 hours ago ago

        In about 600 million years it is estimated that we would in fact lose too much carbon dioxide for one of the main forms of photosynthesis used by plants...

    • mort96 10 hours ago ago

      I don't understand the point of comments like yours.

      • croisillon 10 hours ago ago

        (not grandparent) well one way to learn of that news is like in typical armageddon movies "humans destroyed earth and now we will all die" ; to which grandparent answers "no we didn't destroy earth (but yes we will all die)"

      • burnt-resistor 5 hours ago ago

        “It is difficult to get a man to understand [climate change], when his salary [as a truck driver] depends on his not understanding it.” ― Upton Sinclair

      • xyst 8 hours ago ago

        It gives them a reason to continue being a parasite on this planet rather than attempt to gather a collective and formulate plans to protect future generations on this planet.

    • andrepd 11 hours ago ago

      Well yeah, it's never really about "save the earth", it's more precisely about "save ourselves by saving an earth that is habitable by humans".

      • burnt-resistor 5 hours ago ago

        While we may need to save some soil, we should think bigger by saving the proper noun planet we inhabit. ;)

      • nlitened 10 hours ago ago

        Humans are literally one of the most adaptive creatures on this planet though

        • vlovich123 10 hours ago ago

          By what metric?

          Humans have been around for what, 600k years? That’s genetically. Behaviorally (abstract reasoning, complex language) is only believed to be about 100k years old. Primates as a branch are only about 65m yold.

          Crocodiles are 200m yold (mostly unchanging) while birds are 150m (wild diversity).

          By whatever metric, humanity has no claim to adaptability as a species because we’re really quite too new on the scene. At best we’re more a virus - came on quick but spread at unprecedented rates all across the world bringing ecological destruction with us.

          We have yet to see if we can survive the Earth’s immune response.

        • burnt-resistor 5 hours ago ago

          We cannot and shouldn't risk "adapting" or evolve to handle famines, hypercanes, or extreme desertification. Instead, we should fix what we broke by using the sky as a sewer for ~200 years from 425 ppm CO2 now back to ~300 ppm then.

        • throw123xz 10 hours ago ago

          And even the most adaptive creatures have limits.

          • drdaeman 9 hours ago ago

            Human intellectual/cognitive capabilities are unprecedented, though.

            I'm not sure if we'll live to see it, but I'd be pretty surprised if some fine day humanity won't evolve enough to abandon the primate bodies and decouple humanity from its biology. That is, I believe we'll eventually give birth to thinking machines, and hopefully they'll keep the humanity going even if other branches would possibly fail to the environmental changes.

            Unless, of course, we won't make ourselves extinct first.