A little knowledge

There is apparently a paper from a couple of years ago that is currently doing the rounds and that argues that the Molar Mass Version of the Ideal Gas Law Points to a Very Low Climate Sensitivity. The suggestion is that it is difficult to determine the surface atmospheric temperature but that it can be done with

a gas constant and the knowledge of only three gas parameters; the average near-surface atmospheric pressure, the average near surface atmospheric density and the average mean molar mass of the near-surface atmosphere.

and, given this, no one gas has an anomalous effect on atmospheric temperatures that is significantly more than any other gas and there can be no 33°C ‘greenhouse effect’ on Earth, or any significant ‘greenhouse effect’ on any other planetary body with an atmosphere of >10kPa.

The problem is that the method the paper is applying is the ideal gas law. It’s simply a relationship between pressure, density, temperature and molar mass that essentially applies anywhere in an Earth-like planet’s atmosphere. It’s a truism; if you know the values for three of these terms, then you can determine the fourth. It doesn’t tell you anything about why these terms have these values. That you can use it to determine the surface atmospheric temperature from the density, pressure and molar mass doesn’t imply that there is no greenhouse effect, because the greenhouse effect doesn’t imply that the Earth’s atmosphere would no longer satisfy the ideal gas law.

In the case of an Earth-like planet’s atmosphere, the surface atmospheric pressure is essentially the weight of the atmospheric column; this is fixed. The molar mass depends on the composition, so is also fixed. The only two that can vary are the density and temperature. So, should we regard the temperature as depending on the density, or the density as depending on the temperature? The ideal gas law – by itself – can’t tell us, but we can consider other physics.

The density profile in the atmosphere depends on the scale height, which is the vertical distance over which the density decreases by a factor of e (e = 2.718). The scale height is set by the atmospheric temperature; if the atmospheric temperature is high, the scale height will be large, the atmosphere will extend to large heights, and the density (mass per unit volume) will be low. If the temperature is low, the scale height will be low, the atmosphere will be compressed near the surface, and the density will be high.

So, if the surface temperature is low, the atmospheric density will be high, and if the surface temperature is high, the atmospheric density will be low. This is simply a consequence of the ideal gas law; we still haven’t determined why an atmosphere has a certain set of properties. For example, why is the surface atmospheric temperature on the Earth around 288K (15oC)? Well, that’s a consequence of the greenhouse effect.

In the absence of an atmosphere, energy balance would require that surface temperature were 255K; the presence of an atmosphere enhances this by about 33K. Having done so, the atmosphere still satisfies the ideal gas law, so if you know the surface pressure, density, and molar mass, you can certainly determine the surface atmospheric temperature. This does not mean, though, that there is no greenhouse effect, or that climate sensivity is low.

I thought I would end with the relevant part of the poem that gave us the phrase a little knowledge is a dangerous thing:

A little learning is a dang’rous thing;
Drink deep, or taste not the Pierian spring:
There shallow draughts intoxicate the brain,
And drinking largely sobers us again.

This entry was posted in Climate sensitivity, Greenhouse effect, Pseudoscience, Science, The scientific method and tagged , , , , , . Bookmark the permalink.

26 Responses to A little knowledge

  1. Nick Stokes says:

    “A little knowledge”
    The author was, at that stage, in the early part of his PhD. However, an undergraduate should be able to figure that out.

    There was quite a forceful refutation at WUWT.

  2. Oh dear, that’s the second time in the last month or so that Willis and I have agreed on something 🙂

  3. What exacly do we understand under the greenhouse effect? I hope not in the literally sense? This was already rejected by Fourier ca. 200 years ago. I’m not a scientist but this is the impressions I get from the blogosphere.

  4. This is the same guy that is active on Twitter with the handle “@1000Frolly”.

    He works in coal mining and claims he has an effective way to reduce emissions :

    “I have cut emissions equal to 250,000 t/CO2-e just as something to do to pass the time in my last job in 2012, at a cost of just 0.40c/ton.
    Since then there has been no interest in how I achieved such a massive cut at such a low cost. Go Figure?”

    “Also presented my results at 2 conferences; 16th Nth American Ventilation conference, Colorado 2016 and at Woolongong, Green energy conference 2016. And published in the Journal of applied engineering Science;(link: https://content.sciendo.com/view/journals/jaes/6/1/article-p41.xml)
    There has been ZERO interest.”

  5. dikranmarsupial says:

    Raymond Horstman, the first clear statement of how the greenhouse effect actually works seems to be from Ekholm in 1901

    The atmosphere plays a very important part of a double character as to the temperature at the earth’s surface, of which the one was first pointed out by Fourier, the other by Tyndall. Firstly, the atmosphere may act like the glass of a green-house, letting through the light rays of the sun relatively easily, and absorbing a great part of the dark rays emitted from the ground, and it thereby may raise the mean temperature of the earth’s surface. Secondly, the atmosphere acts as a heat store placed between the relatively warm ground and the cold space, and thereby lessens in a high degree the annual, diurnal, and local variations of the temperature.

    There are two qualities of the atmosphere that produce these effects. The one is that the temperature of the atmosphere generally decreases with the height above the ground or the sea-level, owing partly to the dynamical heating of descending air currents and the dynamical cooling of ascending ones, as is explained in the mechanical theory of heat. The other is that the atmosphere, absorbing but little of the insolation and the most of the radiation from the ground, receives a considerable part of its heat store from the ground by means of radiation, contact, convection, and conduction, whereas the earth’s surface is heated principally by direct radiation from the sun through the transparent air.

    It follows from this that the radiation from the earth into space does not go on directly from the ground, but on the average from a layer of the atmosphere having a considerable height above sea-level. The height of that layer depends on the thermal quality of the atmosphere, and will vary with that quality. The greater is the absorbing power of the air for heat rays emitted from the ground, the higher will that layer be, But the higher the layer, the lower is its temperature relatively to that of the ground ; and as the radiation from the layer into space is the less the lower its temperature is, it follows that the ground will be hotter the higher the radiating layer is.

    Note he doesn’t say the atmosphere is like a greenhouse, but like the glass in a greenhouse.

    Needless to say, skeptic blogs are over a century out of date with the straw men. ;o)

    See the excellent blog post at Steve Easterbrook’s blog, which also has links to the papers.

    https://www.easterbrook.ca/steve/2015/08/who-first-coined-the-term-greenhouse-effect/

  6. Willard says:

    > There was quite a forceful refutation at WUWT.

    David A Smith won that thread:

    The only remaining option is to take the higher ground and disagree with everyone.

    https://wattsupwiththat.com/2018/02/06/ideal-gases/#comment-2277287

    An ideal ClimateBall law.

  7. dikranmarsupial says:

    In other news, the temperature of a thermometer is caused by the depth of mercury in the tube.

  8. JCH says:

    Oh boy, let’s talk on and on about the depth of mercury.

  9. Marco says:

    Ah, Rob I Holmes. This Rob I Holmes:
    https://doi.org/10.1177/0958305X19869522

    “At the request of the Journal Editor and SAGE Publishing, and with the agreement of the author, the following article has been retracted.

    Holmes, R. I. Reducing ventilation air methane emissions cost-effectively and safely. Energy and Environment2016; 27(5): 566–585.

    DOI: 10.1177/0958305X16664834

    Recently, it was brought to the attention of SAGE and the Editors that a version of this paper had been previously published in another journal:

    Holmes, R. I. Mitigating Ventilation Air Methane Cost-Effectively from a Colliery in Australia. Journal of Applied Engineering Sciences 2016; 6(1): 41–50.

    DOI: 10.1515/jaes-2016-0005

    In line with COPE guidance, SAGE and the Editors investigated the similarity of the articles and the author confirmed that, as a PhD student and not being fully aware of publishing ethics practices, he had simultaneously submitted similar versions of the manuscript to both journals. The author apologises for this error. For reasons of redundant publication, this paper has been retracted.”

    Of additional relevance: that paper in JAES explicitly acknowledges the strong impact of greenhouse gases on global warming, unlike his later paper(s), published through a recognized predatory publisher. And then Holmes gets his PhD in 2019 based on that paper on methane emission reductions…

  10. Marco,
    A bit odd. I guess it’s possible that someone might not realise that it’s regarded as unethical to submit the same paper to two different journals, but it’s hard to see why it isn’t an obviously something one should really not do.

  11. Willard says:

    > he had simultaneously submitted similar versions of the manuscript to both journals

    Counterpoint:

  12. Windchaser says:

    A bit odd. I guess it’s possible that someone might not realise that it’s regarded as unethical to submit the same paper to two different journals, but it’s hard to see why it isn’t an obviously something one should really not do.

    Hmmm. This is something his advisor should’ve caught.

    Likewise… your advisor should smack you down (gently) if you try to say that the Ideal Gas Law can overturn a century of physics, much less if you try to publish it.

  13. As a reviewer, giving my labour for free, in the interests of the scientific community, I am delighted when an author wastes my time in the interests of getting his/her work published in the highest ranking journal that will accept it in the minimum possible time.

  14. dikranmarsupial says:

    Having said which, if it is wasting the time of Energy and Environment, then there is a certain ironic justice about it ;o)

  15. dikranmarsupial says:

    Many academic ethics questions are answered reasonably well by the Golden Rule (“do unto others…”), you just need to put yourself in the position of the other people involved and ask yourself how they would view it. It’s hardly rocket science or brain surgery, but it is surprising how apparently intelligent people fail to consider these things.

    BTW Dr Frolly has promulgated Salby’s talks in YouTube, which I think speaks volumes.

  16. Willard says:

    > Many academic ethics questions are answered reasonably well by the Golden Rule

    I prefer solutions:

  17. dikranmarsupial says:

    s/answered reasonably well by/generally solved by applying/g

    Not that I would be against the anonymized reviews and decisions being made publicly available. Not sure about the rejected papers as that might leak the author’s “intellectual property” before they wish.

  18. Willard says:

    > s/answered reasonably well by/generally solved by applying/g

    Whether journals should demand that an author refrains from submitting elsewhere may not be solved by applying the Golden Rule. In some fields it’s considered a Bad Thing, in others it’s not. “Borrowing” texts used to be bad editing practice. We can now reblog posts directly. Social norms don’t rest on what you, me, or anyone thinks. Even if it did, we’d still need to make sure that inexperienced researchers like Rob get the memo.

    Also, we’re talking about a submission process that can take months. Joseph Martin suggests a three months waiting time, after which the paper could be submitted elsewhere. Michael Spicher recalls that it’d be possible to live with a first come first served policy. Duplicated efforts may not be suboptimal, however multiple reviews ain’t that bad. If the insurance industry found a way to solve multiple insurers claims, editors can do it. The time spent on journal work isn’t justified by acceptance, rejection, or even publication. As long as reviewing or editing improves the quality of papers, all should be well.

    My own interpretation of the Golden Rule would compel me to tweet and blog my science.

  19. dikranmarsupial says:

    “s/answered reasonably well by/generally solved by applying/g”

    That was a bit glib. The golden rule mostly just means you have thought about the constraints and issues of the problem, rather than only your own interests, but acting on it usually requires non-trivial compromise. I also don’t mean a naive application of the Golden rule, for example I suspect most people don’t actually want others to behave towards them in a completely altruistic and selfless manner any more than we do ourselves, so the Golden rule doesn’t require us to sacrifice our needs and wants completely for the sake of others. I should have said it is a pretty good start. If we all followed the golden rule, we wouldn’t need the suggested three month rule as the reviewers probably would want their papers to be reviewed in a timely manner (I’d be O.K. with six months rather than three). My record is waiting three *years* for the first set of reviews, by which time I’d essentially forgotten about the paper and someone (better) else had published the same result (with a much better derivation) during that time so I didn’t bother resubmitting it.

  20. dikranmarsupial says:

    FWIW, I set out a thought experiment which I think clearly establishes that his theory is incorrect, in 9 tweets, starting here:

    His response (at step 4):

    Translation:

    ;o)

  21. Windchaser says:

    Dikran, (re: Twitter example)

    The Ideal Gas Law won’t hold near 0K – or more generally, near the boiling/condensation point of the gas. Near that point, the gas stops being “ideal” in the thermodynamic sense, as individual particles begin to interact more with each other.

  22. izen says:

    Shorter folly;-

    As mercury expands and its density decreases in a thermometer, its temperature increases.
    Therefore the temperature is determined by the expansion/change in density.

  23. dikranmarsupial says:

    @windchaser, as it is a thought experiment, there is no reason the atmosphere can’t be an ideal gas, rather than a real one. AFAICS it shows that if there is a “residual” then it is due to some non-ideal aspect of the gas or its radiative properties.

  24. Holger says:

    @dikranmarsupial
    If this guy ever had solved the full compressible Navier-Stokes equations including radiation, he would know how temperature is determined. Certainly not by the ideal gas equation, which is of course necessary to close the system of equations.

  25. Holger,
    Indeed. I think I’ve made that point before in a post, but can’t seem to find it.

  26. dikranmarsupial says:

    @holger a bit of common sense is all that is required to be at least deeply, deeply skeptical, even WUWT drew a line at this one! ;o)

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