Skip to comments.Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics
Posted on 02/11/2010 11:47:02 PM PST by Southack
Falsification Of The Atmospheric CO2 Greenhouse Effects
The atmospheric greenhouse effect, an idea the authors trace back to the traditional works of Fourier 1824, Tyndall 1861 and Arrhenius 1896, but which is still supported in global climatology, essentially describes a fictitious mechanism by which a planetary atmosphere acts as a heat pump driven by an environment that is radiatively interacting with but radiatively equilibrated to the atmospheric system.
According to the second law of thermodynamics such a planetary machine can never exist. Nevertheless, in almost all texts of global climatology and in widespread secondary literature it is taken for granted that such a mechanism is real and stands on a firm scientific foundation. In this paper the popular conjecture is analyzed and the underlying physical principles clarified.
By showing that (a) there are no common physical laws between the warming phenomenon in glass houses and the fictitious atmospheric greenhouse effects, (b) there are no calculations to determine an average surface temperature of a planet, (c) the frequently mentioned difference of 33 °C is a meaningless number calculated wrongly, (d) the formulas of cavity radiation are used inappropriately, (e) the assumption of a radiative balance is unphysical, (f) thermal conductivity and friction must not be set to zero,
the atmospheric greenhouse conjecture is falsified.
Introduction Recently, there have been lots of discussions regarding the economic and political implications of climate variability, in particular global warming as a measurable effect of an anthropogenic, i.e. human-made, climate change. Many authors assume that carbon dioxide emissions from fossil-fuel consumption represent a serious danger to the health of our planet, since they are supposed to influence climate, in particular the average temperatures of the surface and lower atmosphere of the Earth. However, carbon dioxide is a rare trace gas, a very small part of the atmosphere found in concentrations less than 0.04 volume percent.
Among climatologists, in particular those affiliated with the Intergovernmental Panel of Climate Change (IPCC), there is a scientific consensus" that the relevant climate mechanism is an atmospheric greenhouse effect, a mechanism heavily reliant on the presumption that radiative heat transfer dominates over other forms of heat transfer such as thermal conductivity, convection, condensation, et cetera. Supposedly to make things more precise, the IPCC introduced the notion of radiative forcing, tied to an assumption of radiative equilibrium.
However, as countless examples in history have shown, scientific consensus" bears no resemblance whatsoever to scientific validity. Consensus" is a political term, not a scientific one. From the viewpoint of theoretical physics, a radiative approach to the atmosphere using physical laws such as Planck's and Stefan-Boltzmann's, which only have a limited range of validity definitely fails to intersect with atmospheric dynamics and must be questioned deeply.
In other words, applying cavity radiation formulas to the atmosphere is sheer nonsense.
Global climatologists claim that the Earth's natural greenhouse effect keeps it 33°C warmer than it would be without trace gases in the atmosphere. 80 percent of this warming is attributed to water vapor and 20 percent to the 0.0385 volume percent of CO2. If CO2 exhibited such an extreme effect, however, this would show up as a thermal conductivity anomaly even in an elementary laboratory experiment. Carbon dioxide would manifest itself as a new kind of 'super-insulation,' wildly violating the conventional heat-conductivity equation.
Such anomalous heat transport properties never have been observed in CO2, of course. The influence of CO2 on climate was discussed thoroughly in a number of publications that appeared between 1909 and 1980, mainly in Germany. The most influential authors were Möller, who also wrote a textbook on meteorology, and Manabe. It seems that the combined work of Möller and Manabe has had a significant influence on the formulation of modern atmospheric CO2 greenhouse conjectures. In a very comprehensive report from the US Department of Energy (DOE), which appeared in 1985, the atmospheric greenhouse hypothesis was cast into its final form and became the cornerstone in all subsequent IPCC publications.
Of course, although the oversimplified picture drawn by IPCC climatology is physically incorrect, a thorough analysis might reveal some non-negligible influence of certain radiative effects (apart from sunlight) on the weather and hence on its local averages, the climate, which could be dubbed a CO2 greenhouse effect. But then, even if the effect is claimed to serve only as a genuine trigger of a network of complex reactions, three key questions would remain:
1. Is there a fundamental CO2 greenhouse effect in physics? 2. If so, what is the fundamental physical principle behind this CO2 greenhouse effect? 3. Is it physically correct to regard radiative heat transfer as the fundamental mechanism controlling the weather, setting thermal conductivity and friction to zero?
In the language of physics an effect is a not-necessarily evident but reproducible and measurable phenomenon together with its theoretical explanation. Neither the warming mechanism in a glass house nor the supposed anthropogenic warming is an "effect" in this sense of the definition: In the first case (a glass house) one encounters a straightforward phenomenon.
The second case (the Earth's atmosphere) one cannot measure directly, rather, one can only make heuristic calculations.
Explaining the warming mechanism in a real greenhouse is a standard problem in undergraduate courses, in which optics, nuclear physics and classical radiation theory are dealt with.
The atmospheric greenhouse mechanism is a conjecture that can be proved or disproved by concrete engineering thermodynamics. Exactly this was done many years ago by an expert in this field, namely Alfred Schack, who wrote a classical textbook on the subject. In 1972 he showed that the radiative component of heat transfer by CO2, though relevant in combustion chamber temperatures, can be neglected at atmospheric temperatures.
CO2's influence on the Earth's climate is definitively immeasurable.
The warming mechanism in real greenhouses For years, the warming mechanism in real greenhouses, designated the greenhouse effect", has been commonly misused to explain the conjectured atmospheric greenhouse effect. In school books, in popular scientific articles, and even in high-level scientific debates, it has been stated that the mechanism observed within a glass house is similar to anthropogenic global warming.
Meanwhile, even mainstream climatologists admit that the warming mechanism in real glass houses must be strictly distinguished from the claimed CO2 greenhouse effect. Nevertheless, one should look at the classical glass house problem to recapitulate some fundamental principles of thermodynamics and radiation theory. In our technical paper the relevant radiation dynamics of the atmospheric system are elaborated on and distinguished from the glass house set-up. In section 2.1.5 many pseudo-explanations in the context of climatology are falsified by just three fundamental observations of mathematical physics.
The Sun and radiation A larger portion of the incoming sunlight lies in the infrared range than in the visible range. Most papers that cover the supposed greenhouse effect completely ignore this important fact. Especially on a hot summers day, every car driver knows about the greenhouse effect. One does not need to be an expert in physics to explain immediately why the car gets so hot inside: The Sun has heated the car's interior. However, it is a bit harder to answer the question why it is cooler outside the car, although there the Sun shines onto the ground without obstacles. Undergraduate students with standard physical recipes at hand can easily explain" this kind of a greenhouse effect.
On a hot summer afternoon, temperature measurements inside and outside a car were performed with a standard digital thermometer. These measurements are recommended to every climatologist who believes in the CO2-greenhouse effect, because they show that the alleged effect has nothing to do with trapped thermal radiation. Neither the infrared absorption nor reflection coefficient of glass is relevant in this explanation of the real greenhouse effect, only the panes of glass hindering the movement of air.
This text is a recommended reading for all global climatologists referring to the greenhouse effect: It is not the trapped" infrared radiation which explains the warming phenomenon in a real greenhouse - it is the suppression of air cooling.
The fictitious atmospheric greenhouse effects Depending on the particular school and the degree of popularization, the assumption that the atmosphere is transparent to visible light but opaque to infrared radiation supposedly leads to a warming of the Earth's surface and/or a warming of the lower atmosphere and/or a warming of a certain layer of the atmosphere and/or a slow-down of the natural cooling of the Earth's surface and so forth.
Sir David King, former science advisor of the British government, stated that global warming is a greater threat to humanity than terrorism. In countless contributions to newspapers and TV shows in Germany the popular climatologist Latif continues to warn the public about the consequences of rising greenhouse gas (GHG) emissions. Yet even today it is impossible to find a book on nonequilibrium thermodynamics or radiation transfer where this presumed effect is derived from first principles.
The main objective of our paper is not to draw the line between error and fraud, only to find out whether the greenhouse effect appears or disappears within the frame of physics. Therefore, in Section 3.3 several different variations of the atmospheric greenhouse hypotheses are examined and disproved. The authors restrict themselves to statements that appeared after a publication by Lee in the well-known Journal of Applied Meteorology 1973, see Ref.  and references therein.
Lee's 1973 paper is a milestone. In the beginning Lee writes: The so-called radiation `greenhouse' effect is a misnomer. Ironically, while the concept is useful in describing what occurs in the earth's atmosphere, it is invalid for crypto-climates created when space is enclosed with glass, e.g. in greenhouses and solar energy collectors. Specifically, elevated temperatures observed under glass cannot be traced to the spectral absorptivity of glass. The misconception was demonstrated experimentally by R. W. Wood more than 60 years ago and recently in an analytical manner by Businger.
Fleagle and Businger devoted a section of their text to the point, and suggested that radiation trapping by the earth's atmosphere should be called `atmosphere effect' to discourage use of the misnomer. In spite of the evidence, modern textbooks on meteorology and climatology not only repeat the misnomer, but frequently support the false notion that `heat-retaining behavior of the atmosphere is analogous to what happens in a greenhouse' (Miller, 1966). The mistake obviously is subjective, based on similarities of the atmosphere and glass, and on the `neatness' of the example in teaching. The problem can be rectified through straightforward analysis, suitable for classroom instruction.
Lee continues his analysis with a calculation based on radiative balance equations, which are physically questionable. The same holds for a comment by Berry on Lee's work. Nevertheless, Lee's paper is a milestone, marking the day after every serious scientist or science educator is no longer allowed to compare the greenhouse with the atmosphere, even in the classroom, which Lee explicitly refers to.
In section 3.3 of our paper, many different versions of the atmospheric greenhouse conjecture are examined and disproved. In conclusion, the authors observe the following: that even today the atmospheric greenhouse effect" does not appear - in any fundamental work on thermodynamics - in any fundamental work on physical kinetics - in any fundamental work on radiation theory that the definitions given in the literature beyond straight physics are very different and, partly, contradict each other.
The conclusion of the US Department of Energy All fictitious greenhouse effects have in common one and only one cause: A rise in the concentration of CO2 in the atmosphere leading to higher air temperatures near the ground. Lee's 1973 result that the warming phenomenon in a glass house does not compare to the supposed atmospheric greenhouse effect was confirmed in the 1985 report of the United States Department of Energy Projecting the climatic effects of increasing carbon dioxide".
In this comprehensive pre-IPCC publication MacCracken explicitly states that the terms greenhouse gas" and greenhouse effect" are misnomers.
Section 3.5 discusses the concepts of absorption, emission and reflection, recommended reading for those who wish to know the calculations behind the conclusions.
Section 3.6 the classic hypotheses of Fourier, Tyndall and Arrhenius are analysed in detail, followed by modern versions of it, and it is concluded that :
In the 70s, computer simulations of the "global climate" predicted for a doubling of the CO2 concentration a temperature rise of about 0.7 9.6 degrees Kelvin. Later computer simulations pointed towards a null effect. In the IPCC 1992 report, computer simulations of the global climate" predicted a global temperature rise of about 0.27 - 0.82K per decade. In the IPCC 1995 report, computer simulations of the global climate" predicted a global temperature rise of about 0.08 - 0.33K per decade In 2005, computer simulations of the global climate" predicted for a doubling of the CO2 concentration a global temperature rise of about 2 - 12K, whereby six so-called scenarios have been omitted that yield a global cooling.
To derive climate catastrophes from these computer games and to scare mankind to death is a crime.
Section 3.7 discusses the fallacy of radiative balance, from which the following pertinent points are taken: - For instance, average" temperatures are calculated for an Earth without an atmosphere and for an Earth with an atmosphere. Amusingly, there seem to exist no calculations for an Earth without oceans opposed to calculations for an Earth with oceans.
- Though there exists a huge family of generalizations, one common aspect is the assumption of a radiative balance, which plays a central role in the publications of the IPCC and, hence, in the public propaganda. In the following it is proved that this assumption is physically wrong.
- Unfortunately this [conservation laws (continuity equations, balance equations, budget equations) cannot be written down for intensities] is done in most climatologic papers, the cardinal error of global climatology, that may have been overlooked so long due to the oversimplification of the real world problem towards a quasi one-dimensional problem. Hence the popular climatologic radiation balance" diagrams describing quasi-one-dimensional situations (cf. Figure 23) are scientific misconduct since they do not properly represent the mathematical and physical fundamentals.
The reader of this non-technical summary is urged to review all of sections 3.7 and 3.8 in their original format in order to appreciate the issues in hand and understand this further point : that there is no physically meaningful global temperature for the Earth in the context of the issue of global warming. While it is always possible to construct statistics for any given set of local temperature data, an infinite range of such statistics is mathematically permissible if physical principles provide no explicit basis for choosing among them. Distinct and equally valid statistical rules can and do show opposite trends when applied to the results of computations from physical models and real data in the atmosphere. A given temperature field can be interpreted as both `warming' and `cooling' simultaneously, making the concept of warming in the context of the issue of global warming physically ill-posed."
Section 4 discusses the foundations of climate science, whilst the limits of computer models are also pointed out, with this pertinent quote by eminent theoretical physicist Freeman J Dyson: The real world is muddy and messy and full of things that we do not yet understand. It is much easier for a scientist to sit in an air-conditioned building and run computer models, than to put on winter clothes and measure what is really happening outside in the swamps and the clouds. That is why the climate model experts end up believing in their own models.
It cannot be overemphasized that even if the equations are simplified considerably, one cannot determine numerical solutions, even for small space regions and even for small time intervals. This situation will not change in the next 1000 years regardless of progress made in computer hardware. Therefore, global climatologists may continue to write updated research grant proposals demanding next-generation supercomputers ad infinitum. As the extremely simplified one-fluid equations are unsolvable, the many-fluid equations would be more unsolvable, the equations that include the averaged equations describing the turbulence would be yet more unsolvable, if unsolvable" had a comparative. Regardless of the chosen level of complexity, these equations are supposed to be the backbone of climate simulations, or, in other words, the foundation of models of nature. But even this is not true: In computer simulations heat conduction and friction are completely neglected, since they are mathematically described by second order partial derivatives that cannot be represented on grids with wide meshes.
Hence, the computer simulations of global climatology are not based on physical laws. The same holds for the speculations about the influence of carbon dioxide. The reader is urged to review section 4.3 on Science and Global Climate Modelling in its entirety in order to fully appreciate the closing remarks of that section :
Modern global climatology has confused and continues to confuse fact with fantasy by introducing the concept of a scenario replacing the concept of a model. In Ref.  a clear definition of what scenarios are is given: Future greenhouse gas (GHG) emissions are the product of very complex dynamics systems, determined by driving forces such as demographic development, socioeconomic development, and technological change. Their future evolution is highly uncertain. Scenarios are alternative images of how the future might unfold and are an appropriate tool with which to analyze how driving forces may influence future emission outcomes and to access the associated uncertainties. They assist in climate change analysis, including climate modeling and the assessment of impacts, adaptation and mitigation. The possibility that any single emissions path will occur as described in scenarios is highly uncertain. Evidently, this is a description of a pseudoscientific (i.e. non-scientific) method by the experts at the IPCC. The next meta-plane beyond physics would be a questionnaire among scientists already performed by von Storch or, finally, a democratic vote about the validity of a physical law.
Exact science is going to be replaced by a sociological methodology involving a statistical field analysis and by democratic" rules of order.
This is in harmony with the definition of science advocated by the "scientific" website RealClimate.org that has integrated inflammatory statements, personal attacks and offenses against authors as a part of their "scientific" workflow.
There are so many unsolved and unsolvable problems in non-linearity. And for climatologists to believe they've solved them with crude approximations leading to unphysical results that have to be corrected afterwards by mystical methods flux control in the past, obscure ensemble averages over different climate institutes today, excluding incidental global cooling data by hand merely perpetuates the greenhouse-inspired climatologic tradition of physically meaningless averages and physically meaningless statistical applications. In short, generating statements on CO2-induced anthropogenic global warming from computer simulations lies outside of any science.
Section 5 is the final section of the paper and contains the Physicists Summary, which the reader of this non-technical summary is again urged to review in its entirety. Simply quoting these few lines do an injustice to the entire paper, but set the tone for discrediting the fallacy the UN IPCC is perpetuating, aided in no small measure by many a skeptical scientist who also fails to grasp the fallacy of the so-called greenhouse effect with its double-counting of radiant energy.
The natural greenhouse effect is a myth, not a physical reality. The CO2-greenhouse effect, however, is a manufactured mirage.
Horrific visions of a rising sea level, melting pole caps and spreading deserts in North America and Europe are fictitious consequences of a fictitious physical mechanism which cannot be seen even in computer climate models.
More and more, the main tactic of CO2-greenhouse gas defenders seems to be to hide behind a mountain of pseudo-explanations that are unrelated to an academic education or even to physics training.
The points discussed here were to answer whether the supposed atmospheric effect in question has a physical basis. It does not.
In summary, no atmospheric greenhouse effect, nor in particular a CO2-greenhouse effect, is permissible in theoretical physics and engineering thermodynamics.
It is therefore illegitimate to use this fictitious phenomenon to extrapolate predictions as consulting solutions for economics and intergovernmental policy.
Within The Frame Of Physics By Gerhard Gerlich and Ralf D. Tscheuschner Full paper, 114 pages, 1.54MB at http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.1161v4.pdf
This approved non-technical summary by Hans Schreuder, 24 June 2008
The authors express their hope that in schools around the world the fundamentals of physics will be taught correctly, not by using shock-tactic 'Al Gore' movies and not misinforming physics students by confusing absorption/emission with reflection, by confusing the tropopause with the ionosphere and by confusing microwaves with shortwaves.
My daughter has been fighting the good fight on this front her entire college career. She is now a senior and will be graduating this spring from college with her physics major. :-) Some professors were rabidly pro-global warming. I have always told her that the ones that didn’t say one way or another were probably not pro-global warming, but were protecting their careers.
Thanks for the article. She is having surgery today and I’m saving it for when she is coherent enough to read it.
The paper is mostly spot-on, IMO. One little problem:
“In summary, no atmospheric greenhouse effect, nor in particular a CO2-greenhouse
effect, is permissible in theoretical physics and engineering thermodynamics.”
There actually is an atmospheric greenhouse effect. The atmosphere works exactly like the walls of a real greenhouse - as an insulator. Spontaneous or Anthropogenic CO2 based warming is total BS, though IMO. CO2 gas is not some kind of super-insulator - and statistically speaking - too small to count. Most of their theory revolves around IR absorption and retransmittance altering flux. Problem is, all that happens nearly real time. How much can it really alter the energy balance in terms of atmospheric heat retention?
The IPCC models also contain a (badly) flawed assumption - that warming effects are lasting and precipitate more warming effects. Nah. Any heat not absorbed by the ocean or into the earth itself is radiated off quickly into an immense vacuum with infinitely more power to absorb heat than than the atmosphere has the capacity to store it. The upper atmosphere acts like the glass walls of the greenhouse limiting the percentage of the atmosphere in direct contact with space available as a medium for heat exchange. Heat in the lower atmosphere is effectively sequestered. The only way that changes is if the insulating properties (heat conductance) of the upper atmosphere, or the physical size of the atmosphere, or the rate of convective exchange with the lower atmospher is being changed. Not enough CO2 to substantially alter any of that. CO2 could kill us - it’s poisonous at high enough concentrations.
I think there’s evidence that the water cycle including albedo, cloud albedo (ignored by IPCC), ice, and rates of oceanic circulation (turnover) have the ability to alter global climate - but really they ARE global climate. Can we alter them? Maybe. But that’s not the question the AGW hypothesis poses.
I guess if someone hypothesized that all the climatologists running around in icebreakers taking global temps are causing some small amount of warming by affecting albedo - it would be very hard to dispute on the basis of physical chemistry or pure physics.
So yeah, it’s the Sun. And the water cycle. And the IPCC’s hypothesis can be falsified, IMO. And yes the model attempts to solve an unsolvable equation with too many data points and variables to be plugged into a hypothetical computer with enough processing power. Even if the whole human race were set to the task immediately. And the values of other unsolvable flux equations are fed into it as raw inputs. About as scientific, accurate, and useful as a Ouija board or stopped clock. GIGO. The perfect grant-monkey project.
“When a thing defies physical law, there’s usually politics involved.”
Fantastic clarification of physical ***LAW***. Written in true scholarly tradition honoring the human mind.
Gerlich and Tscheuschner (pronounced I think Gelih and Shoosner), real physicists coming to the rescue of their profession’s credibility crisis.
But this non-tech summary has been around for almost 2 years now, and we can imagine that it would be still buried as ‘heresy’ if not for the unfolding EAU whistle blowing heroism aka ‘Climategate’.
I wonder if the authors suffered socially.
CO2 debunking bookmark for reference
I see a problem in either your reading comprehension or interpreting summation.
The authors say that such ***effects*** as defined as reprducible and measurable are not admissible in law, i.e not possible to explain and ***admit*** into the body of the theoretical LAW.
You on the other hand claim EXISTANCE of the effect because of a crudely reflected extrapolation of a simple human construction, a ‘greenhouse’ or glass house.
The rest of your commentary appears to raise good questions.
And now for the sucker-punch which is appropriate as this is a conservative and therefore superior forum for mainly political discourse. I would say that Gerlich amd Tscheuschner are major league players. You on the other hand appear as a promisng minor leaguer but will need to work more on your thought process precision if you want to make it to the major leagues.
According to the Obama administration, such laws can be repealed!
Lol! Yeah well you know Obama is the Messiah so says Calypso Louis!
Perhaps because English isn’t their first language, the terms used can confuse.
To me, what they were saying was that the laws of thermodynamics demand that heat flow (unaided) from hot to cold; never from cold to hot.
Sure, the atmosphere acts as a blanket, slowing heat transfer from Earth to Space, but no, the blanket isn’t radiating heat back to the Earth itself (their point, as such would violate the laws of thermodynamics).
So since we know that the atmosphere isn’t getting thicker...and since CO2 is such a rare trace gas in the upper atmosphere...
...then we know that either CO2 must have super-amazing insulating ability...or that the so-called “Greenhouse Effect” is in error.
Thank you for the link. Am reading the full paper now. Looks like it deserves to get wider recognition. Will pass it on to friends and colleagues.
Need to mention the JoNova website and Dr. David Evans...
He has a paper that addresses the issue as to whether the predictions of an atmospheric hot spot due to CO2 occur in real world measurements...They seem to be hidden or nonexistant.
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I thought the idea of the greenhouse effect was nothing to do with the incoming solar radiation (IR near or far or visible spectrum) but had to do with the reduction of radiant cooling where C02 and water vapor etc. absorb longer wave earth cooling and reflect it back. This article seems to say it is all about the incoming IR being absorbed.
There is one overriding, AMAZING point in this article - and I have never considered it BUT NOW it seems OBVIOUS!
= = = THE KILLER CONCEPT IS THIS!!! = = =
If CHANGES in CO2 concentration at this LOW level (in forty-nine years beginning in 1958, CO2 increased by approx 62 ppmv - 0.0062% - and is approaching a total concentration of 0.04%)...
... could have such a profound and accumulative effect (FORCING an increase in the average temperature of THE ENTIRE PLANET’S ATMOSPHERE of several degrees in just a few decades, or even a century and a half)...
THEN THIS EFFECT WOULD BE EASILY OBSERVABLE IN LABORATORY EXPERIMENTS!!!
It would NOT be subtle - it would be readily detectable, and a consistent PHYSICS-based explanation and mechanism would exist.
It would NOT be some mysterious effect. This is NOT quantum mechanics! This is “normal” classical physics.
AGAIN - to reprise the argument - AND PLEASE NOTE THE UNITS - CO2 has increased by about six-thousandths of one percent in fifty years. If this continues another 50 or 100 years, disaster awaits - the average temperature of the entire planet will increase 2 - 4 - 6 degrees? (pick a number)
If this CO2 effect existed AND was of this POWER, it would be readily measurable in the lab.
SO - Where is the lab data and analysis supporting this effect - not just computer models - but real-world, reality-based measurements?
Game-Set-Match on JUST this argument alone, IMHO
FREE POWER! hey, it just gets hotter and hotter in here, there must be a way we can build lots of greenhouses and capture all that energy...
I’ve seen this before.
Put simply, the earth is NOT a greenhouse, thus invalidating everything stated after that. Then you come to the fact that if CO2 is such a great insulator, why isn’t it used in construction?
Very, very interesting——MHO tends to agree wholeheartedly. You should forward this info to Sen. James Inhofe-—the biggest critic of CO2 warming, etc.
Thanks for the ping!
I suspect that you didn't fully grasp the article.
I believe the good Senator is following this much more closely then most of us. And at this point has quite a few people keeping track of what both sides may have to say.
It would theoretically be possible for the planet to have enough different positive feedback mechanisms that even though none of them were individually significant, the cumulative effect would be disastrous. What makes the theory implausible is that the planet is known to have gone through conditions far more extreme than anything we have now and returned to a (more or less) equilibrium state. If the planet's ecosystem were prone to thermal runaway it would already have happened at various times when it is known not to have done so. The fact that the planet is habitable suggests very strongly that its ecosystem has some very powerful negative feedback systems.