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posted by janrinok on Friday November 18, @05:14PM   Printer-friendly

https://phys.org/news/2022-11-earth-temperature-millennia.html

The Earth's climate has undergone some big changes, from global volcanism to planet-cooling ice ages and dramatic shifts in solar radiation. And yet life, for the last 3.7 billion years, has kept on beating.

Now, a study by MIT researchers in Science Advances confirms that the planet harbors a "stabilizing feedback" mechanism that acts over hundreds of thousands of years to pull the climate back from the brink, keeping global temperatures within a steady, habitable range.

Just how does it accomplish this? A likely mechanism is "silicate weathering"—a geological process by which the slow and steady weathering of silicate rocks involves chemical reactions that ultimately draw carbon dioxide out of the atmosphere and into ocean sediments, trapping the gas in rocks.

Scientists have long suspected that silicate weathering plays a major role in regulating the Earth's carbon cycle. The mechanism of silicate weathering could provide a geologically constant force in keeping carbon dioxide—and global temperatures—in check. But there's never been direct evidence for the continual operation of such a feedback, until now.

The new findings are based on a study of paleoclimate data that record changes in average global temperatures over the last 66 million years. The MIT team applied a mathematical analysis to see whether the data revealed any patterns characteristic of stabilizing phenomena that reined in global temperatures on a geologic timescale.

They found that indeed there appears to be a consistent pattern in which the Earth's temperature swings are dampened over timescales of hundreds of thousands of years. The duration of this effect is similar to the timescales over which silicate weathering is predicted to act.

The results are the first to use actual data to confirm the existence of a stabilizing feedback, the mechanism of which is likely silicate weathering. This stabilizing feedback would explain how the Earth has remained habitable through dramatic climate events in the geologic past.

"On the one hand, it's good because we know that today's global warming will eventually be canceled out through this stabilizing feedback," says Constantin Arnscheidt, a graduate student in MIT's Department of Earth, Atmospheric, and Planetary Sciences (EAPS). "But on the other hand, it will take hundreds of thousands of years to happen, so not fast enough to solve our present-day issues."

More information: Constantin Arnscheidt, Presence or absence of stabilizing Earth system feedbacks on different timescales, Science Advances (2022). DOI: 10.1126/sciadv.adc9241


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  • (Score: 4, Interesting) by Immerman on Friday November 18, @05:49PM (2 children)

    by Immerman (3985) on Friday November 18, @05:49PM (#1280370)

    Before we take a collective sigh of relief, let's not forget the elephant in the room:

    The Earth is currently NOT in its stable state. In fact it's currently in one of its most unstable states.

    We're currently in an abnormally long interglacial period (extremely unstable, rarely lasts for more than a few thousand years) within a major ice age - which is moderately stable, but there's only been five in the 4,500 million years of Earth's history, covering roughly a combined 15% of the Earth's age. And while the first two lasted for hundreds of millions of years (with billions of years between them), the last three all occurred after the huge diversity of complex life born of the Cambrian explosion, and have only lasted about 10 million years or so.
    https://en.wikipedia.org/wiki/Ice_age#Major_ice_ages [wikipedia.org]

    From our current interglacial period about the only thing we can count on long-term is that it won't last forever. Normally they see a steady cooling trend until glaciation begins to snowball and New York gets covered in a ice a mile deep again. But as mentioned ours is unusually long and warm - a fact commonly attributed at least partially to the fact that we invented agriculture near its beginning, and unlike hunter-gatherers (and wild animals) who move to warmer areas when it cools, farmers are heavily invested in the land, and burn more wood to stay warm instead. In the process releasing CO2, which traps a million times more energy from escaping solar heat. Enough to offset the initially very slow cooling.

    But there's also the other alternative - a bit more warming to completely melt the ice caps, and the planet leaves the ice age to get back to it's "normal" state, a good 5-10C warmer than anything humanity has ever seen. Which might actually be good for us in the long term - but currently humanity is trying to force the change 100s of times faster than it's ever happened before - and the "normal" transition already causes significant extinction events due to species being unable to adapt fast enough, which normally takes thousands of years to recover from. Speed it up, and it'll likely be much worse. Add in the massive extinction event we're already in the middle of thanks to industrial-scale pollution, overfishing, logging, etc. and there's a very real risk that we could be facing ecosystem collapse. Some of us would no doubt survive, we're clever creatures - but we might have to eat mostly algae and yeast for a several millenia.

    • (Score: 2) by PiMuNu on Friday November 18, @07:26PM (1 child)

      by PiMuNu (3823) on Friday November 18, @07:26PM (#1280392)

      > the last three [interglacials] all occurred after the huge diversity of complex life born of the Cambrian explosion, and have only lasted about 10 million years or so.

      Just following your link, I can see

      * Andean Saharan Glaciation -460 to -420 MYears
      * Evolution of land plants -400 MYears
      * Paleozoic Icehouse -360 to -260 MYears
      * Quaternary Glaciation -2.6 MYears

      • (Score: 2) by Immerman on Friday November 18, @08:29PM

        by Immerman (3985) on Friday November 18, @08:29PM (#1280403)

        I'm not sure what you're trying to say? The Cambrian explosion started 538 million years ago.

        And what's with the [interglacial] miscorrection? Interglacial periods are the brief warmer periods that happen *within* an ice age - there's hundreds within each ice age. They're the spikes on the squiggly graphs a little further down the page, which only goes back about half a million years - which is just the recent history of the current ice age. During an ice age they seem to occur every 50-100 thousand years, and only last a few thousand years during which the polar ice caps remain, but the glaciers retreat closer to the (ant)arctic circles, as they are now.

        The light-blue regions on the timeline show the five ice ages (a.k.a. major glaciations, a.k.a. Icehouse Earth conditions - the "ice age" terminology is admittedly poorly defined for historical reasons, and often gets applied to the individual glacial periods within an Icehouse period). The much larger gaps between them separated by several times as long a period of the Earth's normal Hothouse state, where the ice caps had completely melted and the world was MUCH warmer.

  • (Score: 4, Insightful) by Rosco P. Coltrane on Friday November 18, @05:54PM (14 children)

    by Rosco P. Coltrane (4757) on Friday November 18, @05:54PM (#1280372)

    When a rogue species like humans fuck up the climate, the Earth simply waits for it to kill itself off - possibly taking a lot of other species with it. In geological time, it takes but an instance. Eventually, the rogue species disappears and things go back to normal.

    • (Score: 1, Insightful) by Anonymous Coward on Friday November 18, @06:17PM (1 child)

      by Anonymous Coward on Friday November 18, @06:17PM (#1280374)

      As TFS says:

      the planet harbors a "stabilizing feedback" mechanism

      Also newsflash... *everything* harbors a stablizing feedback else it would continue on until it finds a stabilizing feedback. That's why we're not all still exploding out in a ball of flame from the Big Bang. Duh!

      • (Score: 1, Insightful) by Anonymous Coward on Friday November 18, @06:33PM

        by Anonymous Coward on Friday November 18, @06:33PM (#1280379)

        "Mad Max" is coming to a future wasteland near you.

    • (Score: 0) by Anonymous Coward on Friday November 18, @06:19PM

      by Anonymous Coward on Friday November 18, @06:19PM (#1280375)

      And, the best example would be dinosaurs, I presume?

    • (Score: 4, Interesting) by RS3 on Friday November 18, @06:22PM (3 children)

      by RS3 (6367) on Friday November 18, @06:22PM (#1280376)

      I've always thought that way, but the problem is (for those who care anyway) the human suffering and loss in the meantime. I think it's a case of us being aware that we've been contributing, and as we (humans) have been doing, at least try to reduce our impact. As we build out carbon-free (or carbon neutral) infrastructure, the economies of scale should help accelerate our efforts. PV panels are much much less expensive than they were 10, 20, 30 years ago, for example. I'm encouraged by the use of satellite data to find methane (natural gas) leaks, for instance.

      An interesting website: https://www.worldometers.info/co2-emissions/co2-emissions-by-country/ [worldometers.info]

      --
      Experience enables you to recognize a mistake every time you repeat it.
      • (Score: 2) by RS3 on Friday November 18, @06:40PM

        by RS3 (6367) on Friday November 18, @06:40PM (#1280385)

        BTW, it's interesting to look at the "Per capita" column. Canada is fairly high, but you might expect this with long cold winters.

        I'm a huge fan of building insulation. I talked a friend into (and I helped) using spray polyisocynurate foam insulation when he was rehabbing his house. He has barely used his oil heat system in the past 10 years. In fact, it's been apart for years. He uses a high-efficiency wood pellet stove and his place is very warm. He's in the northern US and gets long cold winters.

        --
        Experience enables you to recognize a mistake every time you repeat it.
      • (Score: 3, Insightful) by cykros on Saturday November 19, @01:17PM (1 child)

        by cykros (989) on Saturday November 19, @01:17PM (#1280487)

        I think the reason for much of the conflict is that "trying to reduce our impact in effective ways " and "politically expedient bullshit" are often quite confused. Especially with things like electric cars being charged on a coal fired infrastructure, turbines and solar panels whose manufacturing process produces about as much CO2 as the systems they're designed to replace, and other measures such as these that get touted by con men and women looking to get elected (so they can, no doubt, go on to promote warfare which generates a heck of a lot more carbon than anything they ever reduce). Or perhaps the ESG scores, which are gamed by companies such that those who actually many times produce MORE carbon can appear to have a higher score than smaller competitors, and dry up the investment dollars in their latest chosen method for maintaining their dominance.

        I'm not a climate denier, but I am pretty prone to rolling my eyes any time it comes up in the sphere of politics. Not saying don't keep trying, but do take a moment to analyze what often amounts to empty virtue signaling.

        • (Score: 1, Touché) by Anonymous Coward on Saturday November 19, @07:55PM

          by Anonymous Coward on Saturday November 19, @07:55PM (#1280535)

          Is the "empty virtue signaling" you fret about any different from essentially unfettered propaganda by trillion dollar companies with a blatant profit-motive? Just so we know to set our outrage level appropriately for those dirty scumbag virtue signalers.

    • (Score: 3, Insightful) by DeathMonkey on Friday November 18, @06:30PM (4 children)

      by DeathMonkey (1380) on Friday November 18, @06:30PM (#1280378) Journal

      It doesn't always "go back" to normal.

      Great Oxidation Event [wikipedia.org]

      The Great Oxidation Event (GOE), also called the Great Oxygenation Event, the Oxygen Catastrophe, the Oxygen Revolution, and the Oxygen Crisis, was a time interval when the Earth's atmosphere and the shallow ocean first experienced a rise in the amount of oxygen. This occurred approximately 2.4–2.0 Ga (billion years) ago, during the Paleoproterozoic era.[2] Geological, isotopic, and chemical evidence suggests that biologically-produced molecular oxygen (dioxygen, O2) started to accumulate in Earth's atmosphere and changed it from a weakly reducing atmosphere practically free of oxygen into an oxidizing atmosphere containing abundant oxygen.[3]

      The sudden injection of toxic oxygen into an anaerobic biosphere caused the extinction of many existing anaerobic species on Earth.[4] Although the event is inferred to have constituted a mass extinction,[5] due in part to the great difficulty in surveying microscopic species' abundances, and in part to the extreme age of fossil remains from that time, the Oxygen Catastrophe is typically not counted among conventional lists of "great extinctions", which are implicitly limited to the Phanerozoic eon.

      Sometimes we find a whole new local maxima or minima to call home!

      • (Score: 2) by Rosco P. Coltrane on Friday November 18, @07:39PM (3 children)

        by Rosco P. Coltrane (4757) on Friday November 18, @07:39PM (#1280396)

        What I meant was, the Earth will return to some state that supports life of some sort. In other words, it'll reach a new normal. The weather going into a runaway reaction and either creating a superhot Venus-like cauldron, or going permanently cold and turning the planet into a snowball forever, will not happen. The only thing that'll happen is, the responsible species - and the innocent ones that are unsuited to the new environment - will die off, and then life will carry on in another form with a new equilibrium.

        • (Score: 4, Informative) by Immerman on Friday November 18, @09:23PM (2 children)

          by Immerman (3985) on Friday November 18, @09:23PM (#1280406)

          > The weather going into a runaway reaction and either creating a superhot Venus-like cauldron, or going permanently cold and turning the planet into a snowball forever, will not happen.

          It's *already* happened to every other planet in the solar system, and it's definitely in our own future within a few billion years as the sun heats up and boils away our oceans.

          It's not a realistic risk of our current climate problems, but it's absolutely on the table long-term.

          What is a real risk are the normal extremes of our planet - we're currently in an unusually long interglacial period, one of the most unstable states the planet is ever in, and there's only two ways that ends: the glaciers return, burying most of the middle latitudes in a mile or so of ice, leaving only the tropics horpitable, or we tip out of the Icehouse state the planet has been in for the last tens of millions of years into the planet's normal Hothouse state, which is 5-10C hotter and tends to feature lots of deserts, swamps, and jungles.

          The latter is probably the choice to pick, but the transition tends to be environmentally devastating as species can't adapt fast enough, and it takes millenia for biodiversity to recover. And we're currently on track to push the transition far faster than it's ever happened before, which is likely to be far more devastating.

          • (Score: 0) by Anonymous Coward on Friday November 18, @11:47PM (1 child)

            by Anonymous Coward on Friday November 18, @11:47PM (#1280416)

            Bb..ut can't we just move to Mars if that happens?

            • (Score: 1) by khallow on Saturday November 19, @06:52AM

              by khallow (3766) Subscriber Badge on Saturday November 19, @06:52AM (#1280468) Journal
              We could always move to Earth, if that happens. I guess you missed the part where it's better for humans than the present environment!
    • (Score: 5, Funny) by Opportunist on Friday November 18, @06:35PM (1 child)

      by Opportunist (5545) on Friday November 18, @06:35PM (#1280380)

      Two planets meet.

      "Dude, you look horrible, what's wrong?"
      "I got homo sapiens"
      "Ah, don't worry, it will pass"

      • (Score: 0) by Anonymous Coward on Sunday November 20, @07:50AM

        by Anonymous Coward on Sunday November 20, @07:50AM (#1280630)

        Two planets meet. Boom. Disintegration by gravity, no jokes left.

  • (Score: 2) by HiThere on Friday November 18, @06:35PM (1 child)

    by HiThere (866) on Friday November 18, @06:35PM (#1280381) Journal

    The conjecture is clearly true, based on palentological records, but the time scale is longer than millinea. Well, the summary text indicates hundreds of millinnea, and that sounds about right. But the headline is excessively short sighted.

    One of the proposed ways a dealing with excess CO2 is the grind up certain rocks [olivine in the report I saw] and expose them to the air. That WILL work, but it's not fast. And it depends on both grinding up the rocks and ensuring that they are sufficiently exposed to the air for long enough. Which is why the natural processes take so long.

    --
    Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
    • (Score: 0) by Anonymous Coward on Friday November 18, @11:49PM

      by Anonymous Coward on Friday November 18, @11:49PM (#1280417)

      > hundreds of millinnea

      And that is still less than a million years, a mere blink of the eye on geological times. Mother Gaia doesn't get out of bed for less than a million.

  • (Score: 2, Troll) by bradley13 on Friday November 18, @06:57PM (3 children)

    by bradley13 (3053) Subscriber Badge on Friday November 18, @06:57PM (#1280389) Homepage Journal

    If negative feedback didn't dominate, earth would have turned into a permanent snowball or desert billions of years ago. Within (large) limits, anf over long timescales, it obvious that the earth self-regulates.

    In other words, this seems like another "publish or perish" paper stating the obvious. Maybe documenting the mechanism is new, but I doubt even that.

    --
    Everyone is somebody else's weirdo.
    • (Score: 0) by Anonymous Coward on Saturday November 19, @07:59PM

      by Anonymous Coward on Saturday November 19, @07:59PM (#1280537)

      > "publish or perish"

      This too is a nasty runaway effect in our system. Forget quality, feel the quantity.

    • (Score: 2) by ChrisMaple on Sunday November 20, @05:59AM (1 child)

      by ChrisMaple (6964) on Sunday November 20, @05:59AM (#1280610)

      There is an enormous number of people to whom it is not obvious that in the long term Earth's temperature self-regulates. Many of them think of themselves as ecologists or climatologists.

      • (Score: 0) by Anonymous Coward on Sunday November 20, @07:57AM

        by Anonymous Coward on Sunday November 20, @07:57AM (#1280632)

        Well it's a fucking joke, ain't it. It "self regulates" when in the direct glare of the Sun? Yah OK, I'll buy a bridge too if you have one. Of course it doesn't self regulate. If it self regulated, why would the temperature ever fucking change? Self regulate MY ASS.

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