The reason for Earth’s stable climate over millennia proposed

From the university of Exeter:

Scientists propose solution to ‘Gaia puzzle’

Scientists may have solved a long-standing puzzle over why conditions on Earth have remained stable enough for life to evolve over billions of years.

The ‘Gaia’ hypothesis proposed that living things interacting with inorganic processes somehow keep the planet in a state where life can persist – despite threats such as a brightening sun, volcanoes and meteorite strikes.

The puzzle of how this might work has divided experts for decades, but a team led by scientists from the University of Exeter have proposed a solution.

They say stability could come from “sequential selection” in which situations where life destabilises the environment tend to be short-lived and result in further change until a stable situation emerges, which then tends to persist.

Once this happens, the system has more time to acquire further traits that help to stabilise and maintain it – a process known as “selection by survival alone”.

“We can now explain how the Earth has accumulated stabilising mechanisms over the past 3.5 billion years of life on the planet,” said Professor Tim Lenton, of the University of Exeter.

“The central problem with the original Gaia hypothesis was that evolution via natural selection cannot explain how the whole planet came to have stabilising properties over geologic timescales.”

“Instead, we show that at least two simpler mechanisms work together to give our planet with life self-stabilising properties.”

He added: “Our findings can help explain how we came to be here to wonder about this question in the first place.”

Professor Dave Wilkinson, of the University of Lincoln, who was also involved in the research, added: “I have been involved in trying to figure out how Gaia might work for over 20 years – finally it looks like a series of promising ideas are all coming together to provide the understanding I have been searching for.”

Dr James Dyke, of the University of Southampton, also an author on the paper, said: “As well as being important for helping to estimate the probability of complex life elsewhere in the universe, the mechanisms we identify may prove crucial in understanding how our home planet may respond to drivers such as human-produced climate change and extinction events.”

Creating transformative solutions to the global changes that humans are now causing is a key focus of the University of Exeter’s new Global Systems Institute, directed by Professor Lenton, who said: “We can learn some lessons from Gaia on how to create a flourishing, sustainable, stable future for 9-11 billion people this century.”

The Gaia hypothesis, first put forward by James Lovelock in the 1970s, was named after the deity who personified the Earth in Greek mythology.

The paper, published in the journal Trends in Ecology and Evolution, is entitled: “Selection for Gaia across multiple scales.”

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72 thoughts on “The reason for Earth’s stable climate over millennia proposed

    • That theory predicts that night and winter are as warm as summer and day? Doesn’t sound very good.

      • When we talk about the lapse rate, we talk about the point at which convection will start. So, if the day heats up beyond a certain temperature, convection starts and removes heat from the surface more quickly.

        As far as I can tell, it’s pretty simple.

        • Commie Bob
          That is the mechanism for earth loosing heat from the oceans. What is recorded as the anomalies is the effect the transport of that vapour has on its travels. What nobody has taken the time to understand is – what is the controlling mechanism that determines where that displaces warm water vapour mass goes.

          That mechanism has a profound impact on the anomalies, as does the timing of large heat vapour release..

          The UHA chart as presented tells us nothing but an average. No one is looking at what controls the anomalies. People just cheer when they are favourable to their belief.
          Regards

      • I am sure that solar radiation varies with time of day, season and location. Perhaps you know more than most?

          • Stephen
            No, understanding the influencing mechanisms that control the global average as it is currently recorded is important. That is a key reason why the debate is stalled.
            Regards

          • Ozonebust,

            Since convective changes neutralise radiative imbalances,

            http://www.public.asu.edu/~hhuang38/mae578_lecture_06.pdf

            the only relevant factors are global albedo, external insolation, atmospheric mass and the strength of the gravitational field.

            Convection appears to ensure that global albedo varies when radiative imbalances arise as witness dust storms on Mars (no water) and cloudiness (with water) on Earth and on other planets no doubt convection will use other surface materials and if no such materials are present then simple variation of the rate of convective overturning will suffice

            Thus the factors that control the global average are simple and clear cut and do not include radiative material within the atmosphere.

            The irrelevance of radiative material is politically unacceptable which is why the debate is stalled.

          • Stephen
            I agree with your comments in general. However what you cover is how Earth endeavors to maintain a similar temperature. That has nothing to do with the mechanisms that control the temperature anomalies that are recorded. They are two separate things. Evaporation is not linear or even, it is irregular and very robust at times. The displacement of mass volumes of water vapor into the atmosphere has profound downstream affects such as activating blocking mechanisms, that in turn controls where the heat laden atmosphere travels to and the effects.

            No one is looking at what controls or influences the anomalies. They are simply taken at face value. No questions asked.
            Regards

          • Aren’t the mechanisms that CONTROL the temperature anomalies the mechanisms whereby the Earth maintains a similar temperature?
            I have difficulty seeing them as separate things.
            You could say that the mechanisms that CAUSE the temperature anomalies (such as irregular evaporation) are a separate matter and I would not disagree with that.
            However, in the end, it is average insolation that matters rather than seasonal or diurnal or location based variations so my reply to Steve Richards was correct.

        • I think the naive application of the theory predicts exactly what Hugs says it does. I would bet dollars to donuts that he’s seen it applied in that manner.

      • Hugs,
        Does the word “insolarion” mean anything to you?
        What is the insolation on the night side of Earth?
        What is the mid latitudes insolation when days are 14 hrs long compared to 10 hrs ?

      • You got it, Greg. The rates of evaporation and condensation of water change with solar inputs. More energy inputs, greater rate. Less energy slower rate. The climate remains in a stable state.

        The presence, or not, of life has little influence.

        • It’s not just evaporation. Every property of water is special. I just detailed it all but my comment just evaporated into the ether and I can’t be bothered again.

          The properties of the water molecule is probably the closest there is to a proof that there is a God.

          • – On a Windows system, and mayhaps some others, use of “Ctrl-Z” will often restore a page of text that has accidentally been deleted. Repeated Ctrl-Z s may step you back along the input sequence.
            – You know this [ 🙂 ] but, the occasional copying of text during a reponse is a REALLY good idea.
            Ctrl-A (highlight all) then
            Ctrl-C (copy) then
            right arrow (unhighlight) usually suffices.

            Accidentally hit a key while highlighted and it ALL vanishes ! – Ctrl-Z (usually) brings it back.

            Some may benefit from the following. (If you know heaps about water you probably also know that you should do this or similar :-). )

            – Better still is to paste latest version to a scratchpad occasionally. eg
            > eg in Windows:
            Windows Key – WORDP ENTER – usually opens wordpad.
            Alt-TAB back to text being typed.
            Ctrl A, Ctrl-C, Alt-Tab , Ctrl-V.
            Enter Enter.
            Alt-TAB
            Continue.

            Making multiple copies for a longish response helps – just paste below prioor one in wordpad etc.

            After message is sent, optionally save wordpad copy or l;atest version as a record of what you posted.

          • re “The properties of the water molecule is probably the closest there is to a proof that there is a God.” -> The properties of Oxyhaemoglobin deserves honourable mention in that regard :-).

  1. ” … a long-standing puzzle over why conditions on Earth have remained stable enough for life to evolve over billions of years.”

    Conditions on earth have not remained stable. Ice ages for example.

    Life has evolved in response to changes in conditions on earth.

    Wikipedia tells us …
    Organisms face a succession of environmental challenges as they grow, and show adaptive plasticity as traits develop in response to the imposed conditions. This gives them resilience to varying environments.
    https://en.wikipedia.org/wiki/Adaptation

    • Stable is a relative term that should be stated with limits.
      Earths climate has been stable … enough , and long … enough for us to be commenting here.

  2. It has been Pachamama, not Gaia, whodunit. Now we have the added advantage of having the Pachamama Popey in the Vatican as head of the Catholic Church.

  3. This group of academics obviously never consulted with Slartibartfast.
    Now there’s a philosophy…

    • re paranoia , I thing the BBC paraphrased Douglas Adams there. I’m pretty sure the original text said ” most intelligent life-forms suffer from that”.

      Always better to read the book, than to watch a TV sitcom version.

      • From Chapter 30:
        “No”, said the old man, “that’s perfectly normal paranoia. Everyone in the universe has that.

    • it is sickening that the human species permits this type of virus to continue to feed off it.
      what other species would allow such vermin to continue to drain itself?
      how shameful

  4. Or could it be that all plants and animals are able to move, be it through legs, wings, slithering, spores, seeds, current, wind, etc. Maybe why living organisms are so successful through major climatic shifts is they have adapted to them, they or their offspring just get up and get out of the way. Plants and Animals are way smarter than Humans, they realize they cannot control the weather.

  5. One might suspect that the presence of vast, massive oceans with a ridiculous thermal inertia could have something to do with that.

    Nevertheless, as others pointed out, it’s not *that* stable. Even talking about “millennia” of stability sounds a bit of a stretch, as the warm periods and little ace ages every few centuries demonstrate.

  6. Honest Conclusion: “We don’t understand all of the variables or their myriad interactions that drive terrestrial climates where they will. We don’t even know what all the variables are.”

    Set aside the irrational angst and celebrate the miracle that our blue and green ‘swirly marble’ of a planet represents! It’s a good time to be alive…..

  7. Going to the provided source, the paper is apparently only available pay-walled. Have the paper authors defined “stability” in their context of “stabilising properties over geologic timescales”? “Stability” could mean liquid water present somewhere on the planet; ‘stability” could also mean temperatures between 0°C and 100°C somewhere on the planet. St. Lovelock protect us. Gaia save us CO2-spewing sinners.

  8. “why conditions on Earth have remained stable enough for life to evolve over billions of years.” It is called intelligent design. God has put in place those things that regulate our environment. Let’s be honest. When you consider all the factors that need to be just right to allow life to even begin can you really think if could happen by chance even with billions of years to do it? It takes more faith to believe that than what is stated in the Bible.

    • “Chance” is a confused concept, and this confusion of “chance’ with sentient human intent is what inspires belief in a sentient God.

      “Chance” has no meaning to the universe — this is a human concept that cradles our ignorance. “God” is a vehicle to cradle our ignorance. I’m not saying it’s a bad cradle, but it’s not a cradle that I invoke.

      I do NOT believe in “chance”, really. But lack of chance need not require intent. The universe proceeds as it proceeds, and we humans are its assemblages. The marvel is that we are thinking assemblages who can reflect back upon themselves. We are what the universe IS — a life-finding, life-producing process, even amidst seeming chaos and a seeming heat-death fate (of which I am not convinced). The fact that we can think about the universe does not require that a thought process created us to think — we are just seeing our own selves in the cosmic mirror.

      We are the universe thinking — that’s what the universe does in this form of humans.

    • There is zero evidence supporting the pseudo-science of ID, and all the evidence in the world against it.

      Life didn’t arise early in Earth history by “chance”, but by chemistry.

        • They’re not all random. Genetic mechanisms themselves guarantee many mutations. Sexual reproduction increases variation.

          “Random” mutations may occur at “random” times and places, but that they will and do occur is a certainty. From cosmic rays, environmental pollutants, faulty meiosis and mitosis, you name it. Natural sources of genetic variation abound, hence no need to imagine supernatural sources.

          Please provide evidence that God causes mutations, and point to those for which He’s personally responsible. Please make a testable prediction, subject to being shown false, that God makes mutations, ie demonstrate this hypothesis by the scientific method. Thanks!

          No instance of a mutation caused by God has ever been observed. Every identified cause has been natural, not supernatural, and can be reproduced in the lab.

          To posit divine intervention isn’t only totally unnecessary, but anti-scientific. There is no evidence of God’s having made mutations, nor is there any reason to imagine He does. Indeed, there is every reason, both theological and scientific, to be convinced that He doesn’t.

          I’m sure you aware that the point of science is to find natural explanations for observations of nature.

          • You could say that God uses cosmic rays to make the mutations which He wants, but that’s still just a baseless conjecture, and evidence-free, untestable, hence unscientific, speculation, not a scientific hypothesis.

  9. What is going on at Exeter? Here is Lovelock in his own words :
    James Lovelock reflects on Gaia’s legacy 2014
    Scientist who features in an exhibition opening today in London, talks about Gaia, climate change and whether peer review is necessary.
    https://www.nature.com/news/james-lovelock-reflects-on-gaia-s-legacy-1.15017
    It is incredible – from the Lead paper :
    The Black Queen hypothesis – that production of ‘leaky’ ecological public goods is lost until there is negative frequency-dependent selection on the remaining producers – can help to explain regulation, for example, of the marine nitrogen cycle.”
    I think we have here the post CO2 Chess move!!! Where is the Red Queen? The Bishop is already in the Vatican.

  10. Gaia is Clouds, more or less. Short term catastophe or longer term ice ages, all taken care of. Life adapts to progressive cooling and CO2 levels that result, with gradual extinctions and replacement species adapted to the changing planet. We don’t really control that much energy and matter to make a differencec. Nor the Sun.

    No water = no clouds and no smart lagging atmosphere. The rest is incidental. Obs. PhD please.

    CO2 is innocent, and marginally irrelevant. Just an excuse for a short term subsidy racket that most cannt understand the deceit of, and no one lives long enough to prove either way. Also because it can never be proven. Religious science for the faithful, hard of physics and wannabe fraudsters of the priestly kind. Same old faith for profit racket.

    PS The oceans did not absorb Tropospheric scattered IR from the atmosphere in the near infra red/700micronish. I just checked. This is right on the minimum absorption point for IR spectrum in water.

    So the lost heat didn’t go there. Google it for validation. Simple physics fact. And if it did there would be a loss of equilibrium as the effect is only supposed to vary the atmospheric gradient, not absorb energy from the atmosphere.

    Perhaps it disappeared in the assumptions or they lost it in the final adjustments to the IPCC report?

    If the oceans warmed, there was another reason. Not backscattered IR.

    PPS But the politicians haven’t worked out a new problem to blame and promote as a new disaster for profit – end of the world if we don’t do something, and subsidise a half credible cure for lobbyist profit – yet. PM 2.5’s are less and less likely and don’t have the same ease of exploitation and fear of extreme weather to exploit with phoney statistics., etc. BUT I predict there will be more reasons to be fearful beyond this first of 21st Century”New Religions” of pseudo science for a fast buck, promoting phoney industries and bureaucracies that you must subsidise with taxpayers money to save us from, by law.

    In the end nature will take care of it as humans muddle along in their inflated little bubble, until we are no longer adaptable enough to whatever stable Gaia state the planet has then adjusted to. Hoth?

  11. Well, but that doesn’t explain why the dinosaurs lasted 250 million years and didn’t build cities, but we’ve only been here a couple hundred thousand and we have built cities, does it?
    They also haven’t explained why there hasn’t been any other system that shows signs of life, even in a primitive organic signal, or whether or not there’s any life anywhere else in this solar system, have they? No. They’re just nattering on, being pretentious and smug, and looking for more money so that they don’t have to wait tables at the nearest pub.

    • One of my good friends tells me that dinosaurs did not go extinct they just evolved into the climate sceptics, persistently including myself in there.
      In return, I tell him that he is an automaton, not capable of individual reasoning, just splattering out whatever the latest punch tape he is programmed with.
      Otherwise we get on fine.

  12. It depends what one means by stable. I would say the climate of the earth is not stable because it has gone from full blown ice ages to inter glacial conditions many times. Yes the change is maybe only 4-7c so one can argue from that standpoint the climate is stable. The bottom line is although a 4c and some change in global temperature is not much on the face of it ,the end result is catastrophic. I think the best way to categorize the earth’s climate is it can be argued the earth’s climate is stable but the earth in regards to it’s climate is in a very unstable position, meaning only a very slight change in that temperature can swing the earth back and away from an Ice Age. That making what would be a relatively stable climate, unstable.

  13. The Constructal Law https://constructal.org/ explains it. Systems, as they grow and become more complex, have inherent design features that make them more efficient (for the moment) at channeling flow of energy. When blockages to flow occur at any level from a beaver dam in a stream to an asteroid strike, the system redistributes flow to compensatory channels until the it restabilizes and becomes more efficient again.

  14. The basic stability of the climate, apart from our position in the solar system, is due to the properties of water with respect to gravity; whereby the temperature at which evaporation takes place is determined by the gravity induced pressure and results in the lapse rate traces as amended by Dalton’s Law of Partial Pressures.

    The most obvious demonstration of this is the fact that a kettle boils at 100 C no matter how much you turn up the heat. ( a particular point on the curve). So long as this continues we have no fear of catastrophic global warming. Water will take care of that by merely evaporating faster. So fear not my friends trust your kettle.

    However water is not very good at warming the planet should there be a deficit of solar radiation. Hence the reason why we have such long periods of ice ages interspersed with short warmer periods such we now enjoy. No idea how this warming happens; but it is not due to CO2.

  15. I don’t know for sure and I don’t believe anybody can be sure about was has given us a stable climate +- 10C over the millenium but I do think it has to be relatively simple.
    Reliability theorems say that the more complex a system is the more unstable it becomes.
    There are likely 3 or 4 major climate influences such as the oceans, the sun, the planets stability in orbit. Water in it’s 3 phases is almost certainly the biggest single influence.

    • Water makes it easier for the system to remain hydrostatically stable but convective changes would do it even in the absence of water just by altering the rate of convective overturning.

      http://www.public.asu.edu/~hhuang38/mae578_lecture_06.pdf

      On Mars the dust storms kicked up by faster convective overturning increase albedo so as to reduce the effect of external insolation thereby returning the system to hydrostatic equilibrium.

      Note the current planet wide Mars dust storm.

  16. Earth’s climate hasn’t been stable over 3.5 billion years. Its temperature has fluctuated wildly and widely.

    Ocean temperatures during the Paleoarchean Era of the Archaean Eon (around 3.4 billion years ago) were thought to have been between 55 and 85 °C. But a 2009 Stanford study argued for Archaean ocean temperatures no greater than 40 °C. Hot, but a lot more temperate than 85 °C. That’s still pretty toasty, considering the weaker solar output then.

    https://news.stanford.edu/news/2009/november9/ancient-sea-temperature-111109.html

    But by the Mesoarchean Era (2.8 to 3.2 Ga), the first supercontinent Vaalbara had formed, leading to the Pongola glaciation, c. 2.9 Ga. Valbara began breaking up about 2.8 Ga.

    The massive Huronian (or Makganyene) glaciation, a Snowball Earth event, lasted from 2.4 to 2.1 Ga, during the Siderian and Rhyacian Periods of the Paleoproterozoic Era. Some have attributed the Huronian glaciation to the Great Oxygenation Event (GOE), when increased atmospheric oxygen decreased atmospheric methane. If this GHE-based hypothesis be valid, then here’s an instance of life (photosynthetic, oxygenic cyanobacteria) destabilizing climate.

    There followed the middle of the Proterozoic Eon, the so-called “Boring Billion”, from 0.8 to 1.8 Ga, characterized by apparent environmental and lithospheric stability. It really wasn’t all that dull in the history of life on Earth, but does seem to have lacked major ice sheets. Some important evolutionary events did occur during this interval, however, contrary to the nickname.

    During the Neoproterozoic Era (1000 to 541 Ma), however, ice returned with a vengeance. Rifting leading to the breakup of supercontinent Rodinia, which had formed in the mid-Stenian Period of the Mesoproterozoic Era, occurred during the Tonian Period, starting from 900 to 850 Ma. The subsequent Cryogenian Period (635-720 Ma)) speaks for itself. The greatest ice ages known to have occurred on Earth, the Sturtian and Marinoan Snowball Earth glaciations, occurred during this period.

    The last period of the Neoproterozoic witnessed the fabulous Ediacaran biota, predecessors to the animals of the co-called Cambrian Explosion. Since the Ediacarans were generally smaller and lacked hard body parts, they didn’t fossilize as well as Cambrian forms, so were overlooked until 1958. They had been observed, but were thought to be Cambrian, since the prevailing paradigm taught that there were no Precambrian fossils. It is however hard in many cases to connect the Ediacaran biota with Cambrian animal phyla. The Ediacaran ended with a mass extinction event, caused by its animals consuming most of the bacterial slime mats which formed the basis of their food chain.

    It’s difficult to say what effect life has had on the climate of Earth during our present Phanerozoic Eon, but alarmists are fast to blame the Carboniferous-Permian ice age on a drawdown of CO2 by the land plants which made the coal beds which give the Carboniferous Period its name. More likely, this ice age owed to the arrangement of the continental plates.

    The previous Paleozoic glaciation at the Ordovician-Silurian boundary, and that of our present Cenozoic Era, also look more attributable to tectonic changes than to life.

    • The heat distribution and the shape of basic climate zones around a rotating world including the location of any ice caps would be affected by the land and sea configuration but the average temperature would still be determined by insolation, atmospheric mass and the strength of the gravitational field.
      It is not clear as to how much atmospheric mass has varied over past aeons. Some suggest that it was much greater at the time of the dinosaurs so as to provide the necessary density to provide adequate uplift for huge flying creatures at that time.
      The factor that matters most is atmospheric density at the surface because that determines how much conduction can occur between surface and atmospheric molecules. Greater atmospheric density at the surface allows more effective conduction and a higher surface temperature.
      If the surface density is greater then higher surface temperatures can occur at lower levels of insolation.
      Thus higher atmospheric mass could explain higher global temperatures despite a weaker sun.
      Atmospheric mass also sets the amount of heat that the oceans can retain by affecting the energy needs of the latent heat of evaporation. Water boils at a lower temperature and so boiling requires less energy input at the top of Everest where atmospheric mass above is reduced. More atmospheric mass gives a higher ocean temperature at a lower level of insolation which is consistent with higher ocean temperatures when the sun was weaker.
      We need more data about changes in atmospheric mass over billions of years.

      • Extensive glaciation, reaching into low latitudes, as during Snowball Earth episodes, greatly increases our planet’s albedo. Having less ocean exposed also reduces water vapor in the air.

        Average global temperature during Snowballs has been estimated at around -50 degrees C.

        • Which is not to say that life hasn’t had climatic effects. It definitely has, such as changing the color of the ocean, forming red beds, the White Cliffs of Dover and other Cretaceous features, affecting the chemistry of the air and seas, etc.

          Whether life is chiefly responsible for regulating Earth’s climate, however, I’m not so sure. Life is part and parcel of our water planet, though.

      • Pterosaurs would be able to fly even in our present atmosphere.

        Surface pressure wasn’t much greater during the Mesozoic.

  17. I don’t see any reason to make fun of this paper. It’s a legitimate inquiry, if controversial, and if they did understand stability as well as they hope to it would probably show there is nothing to worry about from changing CO2 from 0.03% of the atmosphere to 0.05%.
    I wonder what James Lovelock thinks of this report…

  18. Ironically, the evolution of life from conception is both observable and reproducible in a limited frame of reference, but a large minority deny the scientific evidence for social progress (i.e. religious/moral philosophy or behavioral protocols). Evolution from an intelligent design is an article of faith. Evolution (i.e. Darwinian, creationism) over longer periods and beliefs about origin are either a myth (e.g. circumstantial evidence, inferred or created knowledge, discontinuous processes, signal fidelity) or a conflation of logical domains adopted by certain mainstream cults that deny human evolution. People want… need to believe, in something, selectively, opportunistically, and the cargo cult of post-normal science is no exception.

    That said, the Earth system can be inferred to have been stable within limited frames of reference (i.e. scientific logical domain) with accuracy inversely proportional to the product of time and space offsets from the observer’s frame of reference. However, it is known that chaotic processes (e.g. human life) can and do diverge wildly, suddenly, and unpredictably within short and over indefinite periods, locally and globally.

    • Evolution is a scientific fact, not a myth.

      The contradictory creation stories in Genesis 1 and 2 are myths. Not that there is anything wrong with that.

      • Human Evolution is a well-developed and supported theory with large gaps in the evidence needed to consider it fact. Certainly not a myth, but there is more concrete evidence in favor of CAGW than there is for human evolution. The difference between the two theories being that there is also a large volume of evidence against the theory of CAGW, as well as competing falsifiable theories, where neither exists for evolution.

        • You are mistaken about the fact of evolution.

          It is a scientific fact, ie an observation, with a body of theory seeking to explain those observations. Same as the heliocentric theory, universal gravitation, the atomic theory of matter, the germ theory of disease, relativity theories and QM.

          There are no “gaps” in the evidence showing evolution to be a fact. Maybe you have the detailed history of life on Earth in mind, rather than the fact that new organisms evolve from existing organisms.

  19. Maybe I’m reading this wrong, but it sounds like the author is saying that Darwinian evolution works on inorganic processes. If, so then he needs to apply for tax-exempt status for his Church of Gia, because this is religion posing as science.

  20. Life is a protester in the universe carrying around a sign that reads, “Down with Entropy”. Like many protesters, life is mistaken, as the low entropy SW our planet converts to higher entropy LW compensates entropy many times over for the aberration of life.

    Edwin Schrodinger’s defined life as something that keeps going much longer than you would expect it to. Life does this by concentrating resources and information in unlikely ways. Selection is brutal. Second chances are rare. Viruses tend towards reduced virulence because those that kill their hosts reproduce less.

    If you insist on pushing the concept of group selection far beyond the limits of genetics, as Lovejoy did with Gaia, sure; but since there is no way to test the concept, it really just restates Schrodinger.

  21. “Creating transformative solutions to the global changes that humans are now causing is a key focus of the University of Exeter’s new Global Systems Institute, directed by Professor Lenton…”

    All you need to know.

    Expect a call from the Prof for more money.

  22. Anthony Watts :
    SERIOUSLY ????
    ( This should be READ while imagining the greatest extent of incredulity that you can muster ).
    YOU ARE……. HAVING US ON !!!??? ……………………AREN’T YOU ??????
    The Universities are Lincoln , Southampt-on and EX-ETER-MARKS THE SPOT-ON !
    The “researchers” ( acolytes ?? ) are Wilkins-on and Lent-on …………….
    and a Dyke !…………..
    Well ….not much I do about that one !!
    .
    “Scientists may have solved a long-standing puzzle over why conditions on Earth have remained stable ”
    .
    It HAPPENED just after the invention of the HORSE , of course !!
    .
    ( Although there is a legal precedent :
    In Hercules case it was Cattle !!! So I four-foot my argument ! )
    .

  23. Unfortunately the paper is beyond pay wall so that I cannot verify what they mean by
    “We can now explain how the Earth has accumulated stabilising mechanisms over the past 3.5 billion years of life on the planet,”

    The only thing that is sure is that their definition of stability must be extremely strange .
    If anything the Earth has always been extremely unstable on geological scales .
    It started with no liquid water and no oxygen .
    Oxygen was deeply destabilizing because it introduced massive oxydation which didn’t exist up to there .
    CO2 went down from 15 % to traces .
    The incoming solar energy has also significantly changed .
    The appearance of water cycle was one of if not THE most massive change of atmospheric and oceanic dynamics .
    The plate tectonics, asteroid impacts and volcanos have been destabilizing and are still destabilizing today .
    The orbital parameters have been changing and are still changing what shows among others in irregular oscillations creating and destroying ice ages . There is nothing stable in these oscillations .
    Etc .

    I suspect that this paper has not much in common with serious science .

  24. The ocean is so large relative to the atmosphere, it stabilizes the atmosphere. It is stable itself as it has a limited range of conditions and changes are slow due to its large mass. Problem solved. Has nothing biological to do with it. The biomass of the ocean is too small. The ocean and atmosphere are also stabilized by convection currents meaning the majority of the mass has to be changed to make a global effect. Other changes on shorter timescales than time required to alter the entire mass have no large effect.

  25. The great stabilizer of Earth’s climate are the oceans I would think.

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