How Atmospheric Pressure Drives Temperatures, Not Trace Gases

Posted: May 17, 2018 by oldbrew in atmosphere, solar system dynamics, Temperature

Credit: [click to enlarge]

This is on similar lines to the ongoing studies of Nikolov & Zeller, featured here at the Talkshop on several occasions. The ‘standard’ tropopause pressure of ~0.1 bar is an interesting factor.

By looking at the temperature of every planet with sufficient atmospheres, we see temps rise along with atmospheric pressure, and not from a trace gas, says Alan Siddons at ClimateChangeDispatch.

Early in the 19th century, scientists began to speculate that the Earth, surrounded by the frigid vacuum of space, was habitable because its atmosphere contained special molecules like CO₂ and water vapor, molecules that can absorb heat rays emanating from the Earth and thereby trap its heat.

That the Earth was warmer than one might expect was apparently confirmed when Kirchhoff’s blackbody concept was adopted.

Today it is considered a matter of course that the Earth’s blackbody temperature is minus 18° Celsius, i.e., around 255 Kelvin, whereas its average temperature is 288 Kelvin.

By the early-20th century, this temperature disparity started to be called The Greenhouse Effect.

NASA lists the predicted blackbody temperatures for the planets in our solar system at Planetary Fact Sheets. What’s intriguing, though, is that through the efforts of NASA and other such agencies, we now have some insight into the atmospheres of these other solar system bodies.

Here, for instance, is the atmospheric temperature profile for Jupiter.

Continued here.

  1. oldbrew says:

    Alan Siddons runs through the numbers here (11 mins.), cross-checking with Wikipedia.

  2. wryheat2 says:

    Scottish physicist James Clerk Maxwell proposed in his 1871 book “Theory of Heat” that the temperature of a planet depends only on gravity, mass of the atmosphere, and heat capacity of the atmosphere. Read more and see a practical example from the Grand Canyon:

  3. stpaulchuck says:

    HERESY!! [you guys had better watch out for mass hysteria from the True Believers of the Church of Anthropogenic Global Warming and their splinter group – the Knights of the Satanic Gases]

  4. oldbrew says:

    wryheat – saying that ‘as you go higher up there is less air above you, and therefore less downward force due to the weight of this air’ leads to the question: what force?

    Weighing machines for example register no such ‘force’. I’m playing devil’s advocate here.

    Btw…Maxwell or Arrhenius – no contest, must be Maxwell.

  5. erl happ says:

    wryheat2. Great site you have. Will return again.

  6. ferdberple says:

    What causes the lapse rate? Because this is what causes the 33 C of surface warming over and above black body. The lapse rate warms the lower atmosphere while cooling the upper atmosphere while the average remains unchanged. It is the warming of the lower atmosphere that increases surface temps by 33C.

    Nowhere does the lapse rate have a term for CO2. Rather the lapse rate is determined by the force of gravity, the amount of work required to compress air and the amount of water in the air.

    No co2.

  7. Graeme No.3 says:

    Very interesting. Playing around with the CO2 content shows some effect.
    820 ppm CO2 temperature 288.07
    1640 ppm CO2 temperature 288.17
    2700 ppm CO2 temperature 288.31

    With this formula the idea floated about atmospheric pressure being much higher in the Mesozoic (so giant pterosaurs could fly) turns out wrong as even a 2% increase in surface pressure brings the surface temperature up to 293K. And according to the latest scare stories that would wipe out all life as we know it.

  8. Roger Clague says:

    we see temps rise along with atmospheric pressure,
    This suggests the pressure p is causing the temperature T

    However it could be that p is rising along with T
    That is T causing p.

  9. Roger Clague says:

    ferdberple says:
    May 18, 2018 at 12:00 am

    the lapse rate is determined by the force of gravity, the amount of work required to compress air and the amount of water in the air.

    mgh = mcT

    T/h = g/c

    lapse rate is caused by gravity g and specific heat of air c

    How is work to compress air included?

  10. oldbrew says:

    RC – re However it could be that p is rising along with T
    That is T causing p.

    Would that be compatible with the tropopause being at 0.1 bar on different bodies?
    Obviously 0.1 bar is a pressure constant in this case.

    See: Common 0.1 bar tropopause in thick atmospheres set by pressure-dependent infrared transparency
    T. D. Robinson & D. C. Catling

  11. oldbrew says:

    This suggests the entire atmospheric concept of climate models is suspect, to say the least.

    6 New Papers: Climate Models Are Literally Worth ZERO – Even Water Vapor + Feedback ‘Does Not Exist’
    By Kenneth Richard on 17. May 2018

    The abysmal track record of computer models in simulating climate trends has increasingly been highlighted in the scientific literature. Recently published papers indicate that in some cases climate models actually get it right zero percent of the time (Luo et al., 2018; Hanna et al., 2018), or that hydrological models are off by a factor of 8 and 4 of 5 simulate trends opposite to real-world observations (Scanlon et al., 2018).

  12. Phoenix44 says:


    Well yes, all models of everything are wrong. Note “models” rather than calculations of proven, fixed laws. The problem with climate science is that it confuses the two. It models assumptions, then claims the intermediate results are fixed laws rather than just calculated assumptions , and that therefore the final results are proven.

    Time and again papers which say that “the models prove…” but models literally cannot prove anything. Alter just one assumption in the model and the results change.

  13. oldbrew says:

    Andrew Montford at The GWPF writes:

    Fortunately, some of the modelling groups have “bias corrected” their outputs. In other words, they have tweaked the numbers through some whizz-bang statistical procedure to make them look a bit more like reality:

    In this study we only use those models where daily mean 10 m wind speed has been locally bias-corrected by using the ‘Inter-Sectoral Impact Model Intercomparison Project’ ISIMIP2b calibration methodology (Lange 2016).

    So the recipe is as follows:

    Build model
    Fudge to make global average of interest look right
    Fudge to make local measure of interest look right
    Make inferences about future.
    Move swiftly onwards and hope nobody checks your work.
    – – –
    Are any of these models based on the atmospheric pressure concept? Not very likely.

  14. Philip Berkin says:

    As a layman, I’ve often wondered how much of the earth’s atmosphere is squashed into pneumatic tyres, gas bottles, aircraft cabins, footballs and so on. Is this subtraction from the natural atmosphere remotely significant? My apologies for being off-topic and, possibly, stupid but this seems like a friendly enough forum to ask.

  15. oldbrew says:

    Philip B – consider that the tropopause (the boundary of our mostly nitrogen/oxygen lower atmosphere) ‘lies, on average, at 17 kilometres above equatorial regions, and above 9 kilometres over the polar regions.’

    So the volume of that really is vast compared to man-made objects.

  16. A C Osborn says:

    It is so refreshing to see more & more Scientists coming out from under the AGW croud and telling it like it is.

  17. blob says:

    Hasn’t the 255K value been wholly debunked as due to falling afoul of Holders inequality by doing SBlaw(mean(Irrad)) instead of mean(SBlaw(Irrad)) over the surface of a sphere?

    The 255K is an upper bound on the temperature without an atmosphere for an object with whatever uniform surface albedo and emissivity is being used. And don’t they even include clouds in the albedo term to get the 255K?

    Look at the moon for a better idea of what the mean temperature would be, it is much colder. However then you can start spinning it faster relative to the sun which will increase the average temperature but now you need to model the thermal resistance/heat capacity of the surface (which is also not uniform)…

  18. B Lynch says:

    Could it be, with respect to more scientists coming out from under AGW, that what we are seeing is a generational development? It’s been almost 30 years that the AGW angle has been in vogue, and new scientists, in any field, might not have a particular allegiance to lines of existing thought; that they’d be more interested in knocking presupposed ideas off their established pedestals. As Thoreau wrote, “One generation abandons the enterprises of another like stranded vessels.”

  19. Roger Clague says:

    oldbrew says:
    May 18, 2018 at 9:14 am
    RC – re However it could be that p is rising along with T
    That is T causing p.

    OB Would that be compatible with the tropopause being at 0.1 bar on different bodies?
    Obviously 0.1 bar is a pressure constant in this case.

    RC -The pressure,p of the tropopause is not standard.
    The tropopause of Venus is at 10^-3 bar and of Earth is at 0.2 bar
    This is a range of pressure of x 200
    The tropopause is where p (= energy density = E/m^3) about 0.1bar = 10kJ/m^3
    Where the weather and the atmosphere effect stop
    This is because it is an indication that the energy density has become too low to allow sufficient molecular interaction to cause the gravito- thermal temperature gradient
    It is not evidence that p causes T
    I do not think this challenges my theory that T causes p

    Compression cannot increase T = average KE of a molecule. That needs an acceleration a.
    a can only be caused by a force, a push.
    This can be only by photons from the Sun
    or gravity, the force of attraction of the Earth

  20. oldbrew says:

    Clive Best writes: On Venus the tropopause lies at 55 km at the top of the H2SO4 clouds where IR radiates freely to space.

    ‘The altitude of the troposphere most similar to Earth is near the tropopause—the boundary between troposphere and mesosphere. It is located slightly above 50 km’ – Wikipedia, Atmosphere of Venus

    Venus – image from the blog post

    See: Astronomers solve temperature mystery of planetary atmosphere
    December 9, 2013

    For Earth the pressure of the troposphere at the equatorial height is ~0.1 bar.

  21. johninboston says:

    Only the first 20 ppm of CO2 have radiative forcing. That’s because it’s logarithmic. has been writing about this as well for years. You can also download for free her skeptic’s handbook which explains why this is true.

  22. oldbrew says:

    Then, in the 1980s, NASA spacecraft discovered that tropopauses are also present in the atmospheres of the planets Jupiter, Saturn, Uranus and Neptune, as well as Saturn’s largest moon, Titan. And remarkably, these turnaround points all occur at roughly the same level in the atmosphere of each of these different worlds—at a pressure of about 0.1 bar, or about one-tenth of the air pressure at Earth’s surface.

    Now, a paper by UW astronomer Tyler Robinson and planetary scientist David Catling published online Dec. 8 in the journal Nature Geoscience uses basic physics to show why this happens, and suggests that tropopauses are probably common to billions of thick-atmosphere planets and moons throughout the galaxy.

    “The explanation lies in the physics of infrared radiation,” said Robinson.

    Read more at:

  23. oldbrew says:

    johninboston says: Only the first 20 ppm of CO2 have radiative forcing.

    Possibly, but convection undermines radiative forcing theory.

  24. Ian Wilson says:


    I know this will not be popular but I believe that Nikolov and Zellar are completely wrong. Their claims are not supported by the Physics.

    Put simply:
    A gaseous atmosphere in equilibrium in a spherical gravitational field does not draw its energy from the gravitational field.

    A gaseous atmosphere is just an amalgam of atoms, ions, and molecules, each of which contains
    3/2 k T of energy – where k is Boltzman’s constant and T is local average temperature.

    If an atmosphere contained zero energy all the atoms would be frozen out on the surface of the planet. The atmosphere’s average temperature would be 0 K = -273 C.

    If you add energy to the individual atoms and molecules in the atmosphere, some of that energy will manifest itself in the form of kinetic energy (KE) and some as gravitational potential energy (GPE). Indeed, the local temperature of the atmosphere at a given point above the ground will simply be determined by the average speed (or average KE) of the atoms and molecules at that location. Similarly, the GPE of the atoms and molecules will be determined by the height of the particles above the ground. [N.B. Some of the energy will be stored in the rotational and vibrational motion of the molecules of the atmosphere, as well.]

    The total amount of energy in the atmosphere at any one time is distributed between the atoms and molecules by:

    1) collisions between particles
    2) the absorption and emission of electromagnetic (EM) radiation by the particles

    If no energy is added to the atmosphere either from the planet below, or from space, then whatever energy is present in the atmosphere will be slowly lost to space by radiation, until the atmosphere returns to the zero energy state.


    If the atoms and molecules of an atmosphere receive a constant flow of energy from:

    a) the planet, in the form of geothermal energy
    b) space, in the form of EM radiation

    they will redistribute this energy amongst all of the particles that make up the atmosphere in such a way that they establish a temperature and pressure profile (with height) that produces an energy loss from the atmosphere that balances the energy gains.

    In other words, the height (i.e. GPE) and temperature (i.e. KE) of any given particle in the atmosphere [and hence the equilibrium temperature and density profiles with height] will simply be a result of the way in which the atmosphere responds to ensure that the total energy loss perfectly balances the total energy gain.

  25. Ian Wilson says:

    My comment has gone to the spam folder

    [mod] recovered, above

  26. oldbrew says:

    IW: the arguments go on – one of the earlier threads chewed this over a fair bit…

    Robinson & Catling graph (Talkshop version)…

    More recent thread:

    Alan Siddons crunches the numbers on-screen, with commentary:

  27. Roger Clague says:

    Ian Wilson says:
    May 19, 2018 at 12:34 am

    the local temperature of the atmosphere at a given point above the ground will simply be determined by the average speed (or average KE) of the atoms and molecules at that location. Similarly, the GPE of the atoms and molecules will be determined by the height of the particles above the ground.

    mgh = mcT T is the atmosphere temperature effect
    T = gh/c
    T is caused by gravity,g and height,h.
    How do g and h cause T?

    T is determined by velocity,v and g is a force which causes acceleration,a.
    I suggest g accelerates the v of molecules.
    Imagine a molecule which moves from the tropopause at 20km, 220K ( 450m/s) to surface at 290K( 500m/s).
    The change of v ( delta v) is 50m/^2. The change in g is 0.06m/s^2. Change of height is 20km.
    delta v = sqrt 2gs Newtons laws of motion
    delta v = sqrt 2 x 0.06m/s^2 x 20 000m
    delta v = sqrt 2400m^2/s^2
    delta v = 50m/s

  28. oldbrew says:

    Lots of verbiage here but no mention of atmospheric pressure – not even in the comments by some well-known people (so far)…

    Energy budgets, climate system domains and internal variability
    Posted on May 22, 2018 by curryja
    by Dan Hughes

    It is not a boundary value problem.

  29. Philip Berkin says:

    Thank you, oldbrew, re question about tyres &c.

  30. Q. Daniels says:

    There’s a lot of thermal transport capacity for parcels in the 1-100 um range. These have a long enough coherence time and enough particles that adiabatic heating and cooling actually matter.

    Below 0.1 bar, there are some other effects that start to matter. One of these is that velocity has an effect on mean free path (always), and this starts to produce significant effects at low densities. Essentially, higher elevations are ‘seeing’ the hotter molecules from below.

  31. Roger Clague says:

    Q. Daniels says:
    May 24, 2018 at 8:58 am

    It seems to me you are using 2 different models.

    Air parcels of 1-100 m-^6 is a continuum fluid concept

    velocity, mean freepath and molecule are statistical gas concepts.

    I think statistical gas mechanics should be used for vertical gradients in the atmosphere
    and continuum fluid mechanics only for horizontal effects such as winds

    Please expand on your last paragraph
    What are the significant effects, and what are low densities?

  32. Q. Daniels says:


    Yes, I’m looking at two different models. One is dominated by small scale fluctuations, and the other individual particles.

    I’ve spent a lot of time looking at the vertical gradient problem. Using statistical mechanics and the canonical ensembles runs into a problem of completeness. It does not currently support any modelling of persistent correlation. I’ve toyed around with the idea of adding quasi-particles to the ensemble (phonons, modons), but that gets ugly really fast.

    An alternate approach is to use some kind of hydrodynamic model, but that also gets ugly when you try to include fluctuations. Navier-Stokes particularly becomes unsolvable for all systems which include fluctuations.

    As for the other effects under gravity I mentioned has an increasing temperature with altitude. The lower bound in our atmosphere is about 1 milli-bar (mesopause/turbopause level).