Study: Weathering of rocks a poor regulator of global temperatures

From the UNIVERSITY OF WASHINGTON and the “rock of ages” department.

Weathering of rocks a poor regulator of global temperatures

A new University of Washington study shows that the textbook understanding of global chemical weathering — in which rocks are dissolved, washed down rivers and eventually end up on the ocean floor to begin the process again — does not depend on Earth’s temperature in the way that geologists had believed.

The study, published May 22 in the open-access journal Nature Communications, looks at a key aspect of carbon cycling, the process by which carbon atoms move between the air, rocks and the oceans. The results call into question the role of rocks in setting our planet’s temperature over long timescales.

“Understanding how the Earth transitioned from a hothouse climate in the age of the dinosaurs to today could help us better understand long-term consequences of future climate change,” said corresponding author Joshua Krissansen-Totton, a UW doctoral student in Earth and space sciences.

The current understanding is that Earth’s climate is controlled over periods of millions of years by a natural thermostat related to the weathering of rocks. Carbon dioxide is released into the air by volcanoes, and this gas may then dissolve into rainwater and react with silicon-rich continental rocks, causing chemical weathering of the rocks. This dissolved carbon then flows down rivers into the ocean, where it ultimately gets locked up in carbon-containing limestone on the seafloor.

As a potent greenhouse gas, atmospheric carbon dioxide also traps heat from the sun. And a warmer Earth increases the rate of chemical weathering both by causing more rainfall and by speeding up the chemical reactions between rainwater and rock. Over time, reducing the amount of carbon dioxide in the air by this method cools the planet, eventually returning the climate to more moderate temperatures — or so goes the textbook picture.

“The general idea has been that if more carbon dioxide is released, the rate of weathering increases, and carbon dioxide levels and temperature are moderated,” co-author David Catling, a UW professor of Earth and space sciences. “It’s a sort of long-term thermostat that protects the Earth from getting too warm or too cold.”

The new study began when researchers set out to determine conditions during the earliest life on Earth, some 3.5 billion to 4 billion years ago. They first tested their ideas on what they believed to be a fairly well-understood time period: the past 100 million years, when rock and fossil records of temperatures, carbon dioxide levels and other environmental variables exist.

Earth’s climate 100 million years ago was very different from today. During the mid-Cretaceous, the poles were 20 to 40 degrees Celsius warmer than the present. Carbon dioxide in the air was more than double today’s concentrations. Seas were 100 meters (330 feet) higher, and dinosaurs roamed near the ice-free poles.

The researchers created a computer simulation of the flows of carbon required to match all the geologic records, thus reproducing the dramatic transition from the warm mid-Cretaceous times to today.

“We found that to be able to explain all the data — temperature, CO2, ocean chemistry, everything — the dependence of chemical weathering on temperature has to be a lot weaker than was commonly assumed,” Krissansen-Totton said. “You also need to have something else changing weathering rates that has nothing to do with temperature.”

Geologists had previously estimated that a temperature increase of 7 C would double the rate of chemical weathering. But the new results show that more than three times that temperature jump, or 24 C, is required to double the rate at which rock is washed away.

“It’s just a much less efficient thermostat,” Krissansen-Totton said.

The authors suggest that another mechanism controlling the rate of weathering may be how much land is exposed above sea level and the steepness of Earth’s surface. When the Tibetan Plateau was formed some 50 million year ago, the steeper surfaces may have increased the global rate

of chemical weathering, drawing down more CO2 and bringing the climate down to today’s more moderate temperatures.

“In retrospect, our results make a lot of sense,” Catling said. “Rocks tell us that Earth has had large swings in temperature over geological history, so Earth’s natural thermostat can’t be a very tight one.”

Their calculations also indicate a stronger relationship between atmospheric CO2 and temperature, known as climate sensitivity. Doubling CO2 in the atmosphere eventually triggered an increase of 5 or 6 degrees Celsius in global temperatures, which is about twice the typical projections for temperature change over centuries for a similar doubling of CO2 due to human emissions.

Though not the final word, researchers said, these numbers are bad news for today’s climate shifts.

“What all this means is that in the very long term, our distant descendants can expect more warming for far longer if carbon dioxide levels and temperatures continue to rise,” Catling said.

The researchers will now apply their calculations to other periods of the geologic past.

“This is going to have implications for the carbon cycles for other times in Earth’s history and into its future, and potentially for other rocky planets beyond the solar system,” Krissansen-Totton said.

###

The study was funded by NASA. The paper: https://www.nature.com/articles/ncomms15423

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72 thoughts on “Study: Weathering of rocks a poor regulator of global temperatures

  1. Five to six degrees C per doubling of CO2? It seems the authors are trying to attribute all temperature changes to CO2 levels, not different geography and therefore oceanic circulation for other factors.

    • I agree, and their conclusion about climate sensitivity assumes that the effect of CO2 on the rate of rock weathering is the main negative feedback (“thermostat”) regulating the Earth’s temperature. But that seems obviously incorrect. On sub-millennial time scales other factors, such as biological feedbacks, are vastly more important.

      It is true that rock weathering is a negative feedback mechanism. The process removes CO2 from rainwater, and hence from the atmosphere, and the rate increases with warmer temperatures and higher carbonic acid levels. Higher atmospheric CO2 accelerates this process two ways: it increases carbonic acid content in rainwater, slightly lowering the water’s pH, and it also causes slightly warmer temperatures through global warming. Both lower pH and higher temperature accelerate rock weathering.

      But on less than multi-millennial time scales it is a very minor feedback. Not only are the feedback mechanisms weak, AR5 estimates that rock weathering removes just 0.3 PgC/yr, which is only 3.4% of the estimated anthropogenic emissions of 8.9 PgC/yr.

  2. The input in all of these computer models relating to climate and CO2 is based on best guesses that are always biased. It’s a lousy, unscientific, way to predict the future.

    • daveandrews723 May 23, 2017 at 10:34 am

      “The input in all of these computer models relating to climate and CO2 is based on best guesses that are always biased. It’s a lousy, unscientific, way to predict the future.”

      It is a way that will protect the ‘scientist’s’ career, tenure, pension, health care, company car, etc.

      What have I got to trump [sorry, overcome] that?

      Auto, aware that asking a guy to understand something that ends her/his paychecks is – kinda – difficult!

    • Well it’s nice they got their model together and the elephant is happily waving his trunk, but how about running some experiments to determine what the equilibrium constants are for the actual reaction of CO2-laden air with various minerals? You know, some empirical meat to go with that huge amount of model salad.

  3. The current understanding is that Earth’s climate is controlled over periods of millions of years by a natural thermostat related to the weathering of rocks.

    Only in his mind. Uff da!

  4. So if they’re wrong, because unverified models are virtually useless at predicting the future and the authors seem to have ignored all other possible natural climate drivers, then this is pointless speculation that cannot be proven or refuted. If they’re right (slim chance) our distant descendants can revel in the tropical atmosphere once enjoyed only by giant lizards and ferns without a lengthy trip to the equator. Sunscreen will be at a premium.

  5. using the latest in climotrological sciencey stuff I regulate the temperature in my home using only CO2, the bad part is when I get it just the right temperature we have to stop breathing! just to be safe her is the /sarc tag

    Cheers!!

    Joe

  6. If in the past it was up to 40 degrees warmer than today (and the planet wasn’t “fried”), then why are we worried about a lousy 3-6 degrees? The big driver, over geologic time scales, is the glaciation cycle. The return of the ice sheets is one of the biggest threats to the human species. That and a large meteor/comet impact. One or both will happen eventually and we will be wiped out if we aren’t ready. Developing our technology (especially abundant energy sources) is our best bet to survive.

  7. A new University of Washington study shows that the textbook understanding of global chemical weathering — in which rocks are dissolved, washed down rivers and eventually end up on the ocean floor to begin the process again — does not depend on Earth’s temperature in the way that geologists had believed.

    The study, published May 22 in the open-access journal Nature Communications, looks at a key aspect of carbon cycling, the process by which carbon atoms move between the air, rocks and the oceans. The results call into question the role of rocks in setting our planet’s temperature over long timescales.

    “Understanding how the Earth transitioned from a hothouse climate in the age of the dinosaurs to today could help us better understand long-term consequences of future climate change,” said corresponding author Joshua Krissansen-Totton, a UW doctoral student in Earth and space sciences.

    The current understanding is that Earth’s climate is controlled over periods of millions of years by a natural thermostat related to the weathering of rocks. Carbon dioxide is released into the air by volcanoes, and this gas may then dissolve into rainwater and react with silicon-rich continental rocks, causing chemical weathering of the rocks. This dissolved carbon then flows down rivers into the ocean, where it ultimately gets locked up in carbon-containing limestone on the seafloor.

    […]

    I was never taught that chemical weathering depended on “Earth’s temperature” or that “Earth’s climate is controlled over periods of millions of years by a natural thermostat related to the weathering of rocks.”

    Firstly, how could the chemical weathering be both dependent on and regulate temperature?

    Secondly, I was taught that chemical weathering rates were thought to play a major role in the long-term changes in atmospheric carbon dioxide and the calcite compensation depths of the oceans.

    The problem here is the automatic conflation of temperature and carbon dioxide.

    • Rock weathering contributes about 0.05 GTs to global Carbon cycle each year.

      Vegetation is about 150.00 GTs per years and Oceans are 94.00 GTs per year.

      “Rock weathering” is an irrelevant miniscule component of the Carbon cycle (but it sure gets climate scientists excited because it has a real “sciency” sound to it.)

      • Bill Illis wrote, “Rock weathering contributes about 0.05 GTs to global Carbon cycle each year.”

        Hmmm… AR5 estimates 0.3 Pg carbon.

        1 Pg = 1 Gt, and 0.3 Gt carbon × (44/12) = 1.1 Gt CO2.

        That’s quite a bit different from your 0.05 figure. Do you have a source for that number? And is it carbon or CO2?

        Obviously both your number and the AR5 number are tiny compared to the other fluxes, on timescales relevant to the AGW debate. But I’m curious.

      • Weathering’s contribution is only relevant on geologic time scales (10’s of millions of years).

      • David Middleton May 23, 2017 at 12:55 pm
        Weathering’s contribution is only relevant on geologic time scales (10’s of millions of years).
        —————–

        But what are the vegetation and oceans contribution to the carbon cycle over those 10″s of millions of years.

        On any time scale, weathering will be miniscule compared to the other drivers of the cycle. It is completely irrelevant to any discussion about what CO2 levels are/were/will be.

    • David Middleton asked, “Firstly, how could the chemical weathering be both dependent on and regulate temperature?”

      That’s what makes it a feedback mechanism (albeit a minor one, in this case).

      Any chain of events in which the causation runs in both directions is a feedback mechanism.

      In this case the feedback is “negative” (stabilizing), and it works like this:

        Higher CO2 → warmer temp & more acidic rain → faster rock weathering → lower CO2

      And, of course, like all feedback mechanisms, it works both ways:

        Lower CO2 → cooler temps & higher rainwater pH → slower rock weathering → increased* CO2

      (* “increased” in this case means “reduced by less” — it is actually other processes which add the CO2 to the atmosphere, causing the increase.)

      Because the signs are opposite (i.e., an increase in a system input triggers a chain of events which causes a decrease in that same input), this is an example of what is said to be a negative feedback, or, in the authors’ terminology, a “thermostat.”

      If the signs were the same (i.e., if an increase in a system input triggered a chain of events which caused another increase in that same input), it would be a positive (amplifying) feedback.

      A common misconception is that positive feedbacks necessarily “run away,” and make a system unstable. That is incorrect. Only extraordinarily strong positive feedbacks can make a system unstable. Those are rare. Most natural positive feedbacks just have a modest amplifying effect.

      • This assumes that “Higher CO2 → warmer temp”…

        Otherwise, yep… CO2 affects the rate of weathering and is in turn affected by the rate of weathering.

        Temperature can be taken right out of the equation.

  8. H20 is amphoteric, quite capable of dissolving rocks on its own. Volcanos also eject Sulfur Dioxide, Sulfuric acid can disolve just about anything. In an acid rain condition that has a mixture of sulfuric and carbonic acid, the carbonic acid might possibly act as a chemical buffer, thereby actually increasing the strength of the sulfuric acid.

    It seems to be another study where the
    the results were predetermined, just my opinion.

  9. “Carbon dioxide in the air was more than double today’s concentrations.”

    I’ll say. In the mid-Cretaceous, it was more than five times today’s 400 ppm. Hence, their ECS “estimate” is way off, even if no other factor in temperature be considered.

    GCMs can’t handle the Cretaceous, probably because they don’t do clouds. A paper proposed that lack of biological CCNs due to the hot oceans may have reduced cloudiness during the Cretaceous.

  10. Read the paper. A pile of modelled assumptions (seafloor chemical weathering) on top of a pile of dubious proxies (pCO2), while ignoring that the main cretacious carbon sink was biological marine calcification. In Texas, the upper cretaceous limestone beds are about 500 meters thick.

    • “ignoring that the main cretacious carbon sink was biological marine calcification”
      They aren’t ignoring it. It’s the point of the focus on weathering rates. On its own, depositing CaCO₃ from a predominantly bicarbonate solution creates an equivalent amount of acid in solution. The process can’t go far unless there is a supply of base stronger than carbonate to counter that. That is where weathering comes in. Basalt rocks can supply that base, enabling the removal of CO₂. And if warming accelerates weathering, that is a very slow negative feedback – the basis of the supposed thermostat.

      • Alkaline (high Na, K) basalts can provide the base. These are usually found on land (subaerial), the province of silicate weathering. Mid ocean ridge basalts, which seemingly would interact directly with the oceans, are not typically alkaline basalts.

  11. Unfortunately, this paper is typical of present-day Climate Science, because it assumes as an established fact that CO2 and only CO2 controls climate. The possibility of other factors being at work is neither considered nor mentioned.

    Here is a single piece of evidence for at least one, very potent factor in driving climate:: the rapid warming that started the present interglacial (and all the preceding interglacials) happened when atmospheric CO2 was at its lowest, around 200 ppm. How do warmists explain this? (they do, but they have to invoke “something else” which started the warming and then went away and hid until it’s needed again). And, to provide symmetry, the rapid cooling that starts each glacial period, happened when CO2 was higher, at around 350 ppm.

    • “it assumes as an established fact that CO2 and only CO2 controls climate”
      Often said here, but “only CO₂” isn’t assumed. Only that putting CO₂ in the air makes it warmer. Other things can happen too. The point of the thermostat hypothesis here is that the response of weathering to warmth, and its effect on acid/base and air CO₂ has a thermostat effect, which will prevail if the other changes are not so linked. A real thermostat is not the only influence on room temperature. But still it works.

      • So if thermostats work, then you agree with Willis E? The thunderstorms produced in the tropics and subtropics will keep the temperature relatively constant (depending on the actual layout of the continents.)

      • The thunderstorms produced in the tropics and subtropics will keep the temperature relatively constant

        thunderstorms limit max temps, and dew points regulate min temp.

      • “The thunderstorms produced in the tropics and subtropics will keep the temperature relatively constant”
        There are a number of feedbacks, both positive and negative. Negative feedbacks have a thermostat-like effect. I’m not convinced that thunderstorms have a dominant effect.

      • “…I’m not convinced that thunderstorms have a dominant effect…”

        Maybe the rocks in your head have become too weathered?

  12. “What all this means is that in the very long term, our distant descendants can expect more warming for far longer if carbon dioxide levels and temperatures continue to rise,”

    As by “the very long term” he explicitly means a age similar to that taken for the Himalayas to form….
    I reckon our descendants will be able to adapt in time.

  13. If sensitivity is around 1 as some studies have concluded, this paper loses it. The idea that sensitivity is in the 5 or 6 range has been pretty much debunked by real-world evidence.

    • Sensitivity without feedbacks is1.1-1.2 (best estimate 1.16). With feedbacks, all the energy budget papers estimate 1.6-1.7. My preferred such paper is Lewis and Curry 2014 because it uses the IPCC AR5 values, and because ittndoes the analysis for different time tranches to show the estimates are robust.

      • Positive feedback loops do exist in nature, but are necessarily rare. Were it otherwise, the climate system and other natural phenomena would self-destruct.

        https://wattsupwiththat.com/2014/06/16/nature-abhors-a-positive-feedback/

        Hence, IMO net feedback effects from rising CO2 are liable to be negative. Thus ECS, if the concept have any reality at all, should be less than 1.2 degrees C per doubling, not more.

        For instance, even if more CO2 does indeed warm the surface, causing more H2O in the air, then evaporative cooling and greater cloudiness ought to counteract any such warming.

  14. A fine example of a junkscience paper,

    Marvelous!

    Meanwhile they say silly things:

    “As a potent greenhouse gas, atmospheric carbon dioxide also traps heat from the sun. And a warmer Earth increases the rate of chemical weathering both by causing more rainfall and by speeding up the chemical reactions between rainwater and rock. Over time, reducing the amount of carbon dioxide in the air by this method cools the planet, eventually returning the climate to more moderate temperatures — or so goes the textbook picture.”

    CO2 does NOT trap heat!

  15. “The researchers created a computer simulation of the flows of carbon ”

    The hierarchy of lies from the least to the most deceptive and viscious:

    Lies,
    Damned Lies,
    Statistics,
    Computer Models

    A computer simulations is mere mathematical onanism. Meat space onanism is more fun and more productive.

    • Rock weathering and CO2 go together just fine… GEOCARB is derived from weathering rates. Somewhere over the last 30 years temperature was conflated with CO2 and weathering over geologic time (without any evidence)… A sort of academic straw man. This paper seems to have defeated that straw man.

      • David that is not my argument. Although the paper argues a different relationship between weathering, temperature and CO2, it still suggests greater sensitivity of global temperatures to CO2 to explain the transition from hot house to ice house climate.

        I am arguing (as have others in the peer reviewed literature) as detailed in the Antarctic Refrigerator effect (http://landscapesandcycles.net/antarctic-refrigeration-effect.html) that the change from hot house to ice house was due to a realignment of the continents resulting in the establishment of the Antarctic Circumpolar Current which then prevented poleward transport of heat. That allowed the Antarctic ice cap and sea ice to form that then began a long process of cooling the deep oceans and eventually the temperatures of upwelled water, which then initiated ice cap formation in the northern hemisphere over 30 million years later than in Antarctica. The vast difference in timing of ice cap formation on the southern and northern poles contradicts any attribution of CO2 as the driver of transition to an ice house climate, no matter what the climate sensitivity is attributed to CO2 or rates of rock weathering.

        CO2 and rock weathering, no matter what their relationship is simply not needed to explain the past 35 million years of cooling temperatures. Their simulation is basically irrelevant.

      • I was agreeing with you. The relationship between rock weathering and CO2 is irrelevant to temperature over geologic time.

      • Jim, the last 55 million years is only one paradise/ice age transition.

        The Carbo/Permian configuration of continents was not conducive to an Antarctic vortex, but the paradise/freezer transition took place anyway.

  16. “Their calculations also indicate a stronger relationship between atmospheric CO2 and temperature, known as climate sensitivity. Doubling CO2 in the atmosphere eventually triggered an increase of 5 or 6 degrees Celsius in global temperatures, which is about twice the typical projections for temperature change over centuries for a similar doubling of CO2 due to human emissions.”

    Comparing todays climate to that of a 100 million years ago is apples and oranges. The Sun was closer, as well as the Moon, so astronomically the Earth was really in a different space so to speak. The continents were located differently, as well as the ocean currents were much different then. The winds were different…
    So suggesting that we may be looking at a climate sensitivity of 6 or 7 in present day Earth based upon those times 100 million YBP is a different kettle of fish. The whole argument for CAWG is exactly this point, and is what is up for debate is how feedbacks in todays Earth will interact with a doubling of CO2. And we are just halfway to a total doubling, so is there any real panic especially that we see after 137 years only a total of .85 C total rise? Most agree that the physics of radiative forcing of a doubling of CO2 would be 1.2 C, and of that doubling, it is still hard to know how much is human caused and what is natural as a result of warming. We don’t have a exact planet to conduct a double blind study on, so probably some things will never be known with any degree of absolute certainty.

    I don’t think I read anything about the freeze thaw cycle in the essay, and 100 million years ago, there wasn’t a lot of frost around. The freeze thaw cycle opens up a lot of fresh rock due to annual fracturing that would make much more surface area of rock available for chemical weathering. Maybe I missed this, but I think this fact would be a considerable consequence on weathering of rocks.

    • Ron Williams May 23, 2017 at 12:21 pm

      I don’t think I read anything about the freeze thaw cycle in the essay, and 100 million years ago, there wasn’t a lot of frost around. The freeze thaw cycle opens up a lot of fresh rock due to annual fracturing that would make much more surface area of rock available for chemical weathering. Maybe I missed this, but I think this fact would be a considerable consequence on weathering of rocks.

      Yup, it was in the essay, but kinda camouflaged, and thus the reason you “missed it”.

      It t’was where the author stated, to wit:

      When the Tibetan Plateau was formed some 50 million year ago, the steeper surfaces may have increased the global rate of chemical weathering, ………..

  17. “The authors suggest that another mechanism controlling the rate of weathering may be how much land is exposed above sea level and the steepness of Earth’s surface. When the Tibetan Plateau was formed some 50 million year ago, the steeper surfaces may have increased the global rate”

    I believe it isn’t the amount of rainfall that is critical for rock weathering. Instead it is the amount glacial erosion that is critical. Today on the outer surface of the rock is the only part of the rock that reacts with the carbonic acid in rain. However when a glacier is actively cutting through rock the granite is pulverized to sand. That dramatically increases the surface area of rock exposed to rain. The larger surface area of freshly created granitic sand will react with a lot more CO2 in the air. The rain just simply washes away the carbonates from the sand into the ocean.

    Today the south ice cap is not moving much so relativity little granite is converted to sand. However in the Tibetan Plateau the glaciers are trying to grind there way down 20,000 feet to see level and creating a lot of sand and silt in the process. Once the Tibetan Plateau uplift started earths CO2 levels started to drop. and the periodic ice ages started. The changing positions on the continents did play a role but I believe the Tibetan Plateau uplift was the major cause of the CO2 drop over the last 100 million years.

    • Steven F,
      It isn’t quite that simple! Mafic rocks with abundant ferromagnesian minerals and calcium-rich feldspars experience more rapid chemical weathering than silica-rich granitic rocks. Therefore, the proportion of the different kinds of rocks exposed during a particular epoch will affect the rate of weathering. Yes, chemical weathering (as well as mechanical transport) will proceed more rapidly with small grain size. However, during glaciation, the fine rock flour produced by glaciers is either at the base of the glaciers or entrained in the ice, where it is not capable of being chemically weathered by rainfall, nor transported to the seas until after the glaciers melt. Also, the low temperatures associated with glaciation reduce the rates of chemical weathering. Incidentally, since you seem to be unfamiliar with the characteristics of glacial till, one of its most important diagnostic features is the large range of particle sizes. It is essentially unsorted! That is to say, boulders the size of a house are as abundant as the “sand and silt” you reference. Also, look up the definition of “grus.”

  18. “The current understanding is that Earth’s climate is controlled over periods of millions of years by a natural thermostat related to the weathering of rocks.”

    Well maybe that’s what you learn when you obtain a geology degree from a blue light special in K-Mart’s climastrology department. I know I’ve posted this many times, but here is the gist of the best theory involving long term ocean chemistry, which just “coincedently” correlates well with global climate.

    http://ftp.earthbyte.org/Resources/Pdf/Muller_etal_2013_Seawater_chemistry_driven_by_Supercontinent_assembly_breakup_dispersal_Geology.pdf
    http://www.whoi.edu/science/GG/geodynamics/2005/images2005/hardie96_GEOL.pdf

    Rates of rock weathering have been known to be controlled by the rate of orogenesis (mountain building) for decades. Where there are mountain ranges there are deposits thousands of feet thick of sediments shed directly off the mountains and the higher the rate up uplift the higher the rate of weathering, both from the physical deformation by tectonics and from the conditions prevalent at high elevations that enhance weathering. Yet, here we are again presented by climate researchers with a study purporting to discover, through models, something that has been observed for a very long time.

    Though temperature does of course have an impact of weathering rates, mostly in the denudation rate of karst topography. Warmer weather equals more humidity equals faster karstification, this is directly observed on the Earth’s surface today — more karstification takes place in warm and humid environments. This is from more available water to mechanically and chemically erode limestone as well as more primary productivity that increases available organic acids. The improper assumption — pseudoscientific dogma — that a doubling of CO2 leads to a global increase of 5 degrees in atmospheric temperatures probably caused them to diminish weathering rate feedback.

  19. “What all this means is that in the very long term, our distant descendants can expect more warming for far longer if carbon dioxide levels and temperatures continue to rise,” Catling {read off the mat….}

    What mat?

    Who filled in the conclusions in the squares on the mat?

  20. The authors suggest that another mechanism controlling the rate of weathering may be how much land is exposed above sea level and the steepness of Earth’s surface. ……………. When the Tibetan Plateau was formed some 50 million year ago, the steeper surfaces may have increased the global rate of chemical weathering, ………..

    OH, ….. WOWEEEEE, …… what a brilliant, well-reasoned statement by the author(s) of the study ……. that is surely deserving of them being awarded Nobel’s Gore-Obama Prize in Climate Junkery.

  21. “…What all this means is that in the very long term, our distant descendants can expect more warming for far longer if carbon dioxide levels and temperatures continue to rise,” Catling said…

    Temperatures that continue to rise means more warming. What an amazing conclusion.

  22. Another master class in devious obscurantism. The most important aspect of silicate weathering is carefully hidden (they imagine that no-one will notice?!) – that is, that weathering produces a general very long term trend of depletion of CO2 from the atmosphere which is the biggest single threat to life on the planet. It is a sword if Damocles hanging over the biosphere, one which during the last few glacial maxima actually started to damage the biosphere for the first time since the Cambrian explosion. But the Climagesterium are terrified of the general public waking up to the fact that fossil fuel burning is profoundly good for the planet 🌎. So they are silent about the big important issue of long term CO2 starvation and instead they obsess at tedious length about trivia such as the temperature dependence of silicate weathering.

    You are on a lifeboat adrift at sea with food and water running low. One crew member breaks down and loses his sanity, and starts babbling incessantly that water is poisonous and that no-one should drink water. What do you do? Put the poor fellow out of his misery and eat him.

  23. Listen to
    Joshua Krissansen-Totton

    talking about

    astrobiology

    before making sure such thing as “astrobiology” really exists outside planet earth.

    And if there’s such thing as “astrobiology” – will it walk upright.

  24. “In retrospect, our results make a lot of sense,” Catling said. “Rocks tell us that Earth has had large swings in temperature over geological history, so Earth’s natural thermostat can’t be a very tight one.”

    We’ve died since long gone – we just didn’t realize.

  25. Cream – Sweet Wine Lyrics

    Who wants the worry, the hurry of city life.
    Money, nothing funny, wasting the best of our life.

    Sweet wine, hay making, sunshine day breaking.
    We can wait till tomorrow.
    Car speed, road calling, bird freed, leaf falling.
    We can bide time.

    Sweet wine, hay making, sunshine day breaking.
    We can wait till tomorrow.
    Car speed, road calling, bird freed, leaf falling.
    We can bide time.

    Who wants the worry, the hurry of city life.
    Money, nothing funny, wasting the best of our life.

    A 10-year old Taylor Swift was shown how to play basic guitar by a computer repair man, setting the pop star on her path.
    3
    In 2007, Britney Spears was banned from the luxurious Hollywood Hotel Chateau Marmont after supposedly spreading her dinner all over her face.

  26. Why does WUWT continue to give nonsense-science top billing? Why make your faithful scientists debunk the junk? Isn’t it about time to differentiate on this blog the science that is reasonable and up for debate as per the scientific method and that which is religious faith (or evil-intentioned) masquerading as science? Anthony should know better, but then most California geologists who want to keep their jobs must advocate AGW. Maybe it is the same with meteorologists.

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