Monday, March 28, 2011

Understanding the Thermodynamic Atmosphere Effect

By Joseph E. Postma (M.Sc. Astrophysics, Honours B.Sc. Astronomy)
March, 2011


This article began as a brief two-page summary of the theoretical development of the “Greenhouse Effect”. After having several discussions with colleagues, it became apparent that its theoretical basis was not widely understood, even though the theory appeared to be believed in implicitly. In a scientific institution it is generally expected that individuals understand the theories they support and believe in, rather than simply being aware of them and believing in them. Therefore it was curious that there seemed to be so little academic understanding of the theory of the Greenhouse Effect, as opposed to simple awareness of it.

Full article


  1. Here is the simpler, earlier, and definitive article on this subject, including the real-world(s) data that makes it obvious, and thus actually proves it:

    Venus: No Greenhouse Effect

    This simple analysis (done by me last November), which James Hansen and other climate scientists (and all of science) should have done and accepted as final nearly 20 years ago, was submitted by me to Physics Today, but is being widely ignored. It should be understood as the true breakthrough article on the subject of the "greenhouse effect".

  2. (Sir) John Houghton (the supposed guru of climate science) in his book "Physics of the Atmospheres" mentions the lapse rate on Earth but completely ignores it for Venus claiming runaway greenhouse effect. The book has many omissions and inconsistencies. One wonders about his motives and/or his understanding.

    A couple of minor points about the sun. The claimed diameter of the sun is based on visual aspects. There is a corona which is outside the visual area. No one knows if the sun has a core which results in a surface. There have been flares claimed to be millions of degrees C. The temperature of the sun is a calculated average based one the blackbody Stefan-Boltzman equation. Actual spectral information shows that the sun does not completely follow the Planck distribution at any temperature. Thus the sun is not a blackbody or maybe the Planck distribution is wrong which might also make the Stefan-Boltzman equation in error.
    There was a recent article by Kopp& Lean which found solar radiation some 5w/m2 lower than the previous accepted value.

  3. Postma's argument boils down to this:
    1. Thermodynamics says the effective black body temperature of the earth is -18C, and this is matched by observation from space.
    2. We observe much balmier temperatures at the earth's surface in practice.
    3. The Greenhouse Theory says the difference is down to the greenhouse effect.
    4. Postma observes that the temperature of -18C occurs at 5km altitude:
    "This altitude is found at about 5km in height above the ground surface by observation. "
    5. He calculates from more thermodynamic theory that we should therefore expect the temperature at the surface of the earth to be 14.5C. Voila! No need for a greenhouse effect.
    The blunder, of course, is that he offers no explanation for the -18C line being at 5km. And the explanation is ... the greenhouse effect?

  4. Anonymous,

    Postma is responding to this question and others in the comments to this thread:

    and also at JoNova in the recent post on the 2nd law of thermodynamics

  5. This is highly misleading and flawed 'science' and I do not think does the anti-warmist camp any good.

    His 'science' assumes that Earth is acting as a 'blackbody'. The point of the Greenhouse effect is that it makes the Earth act as a non-blackbody. CO2 (and H20, CH4 and other gasses) essentially act as a filter of certain wavelenghts. So if you were to look at Earth's emissions spectrum, there would be 'chunks' missing. The Earth maintains a dynamic equilibrium - it radiates as much power as it receives.

    So when you filter out a bit of the radiative spectrum, Earth compensates by increasing output on the other wavelengths, until it exactly compensates - it increases that output by getting hotter!

    Instead of looking like a blackbody at -18C, it looks like a blackbody at -16C with some frequencies missing. It gets a bit hotter to compensate for the missing emission frequencies.

    My analogy would be to a house with central heating. The net heat output by the house (via walls and roof) is the net heat put in by the central heating. If we insulate the roof (block some of the output), the net heat in doesn't change and the net heat out doesn't change ... but the house gets warmer so that extra heat is lost via the walls to compensate for the heat now not lost via the roof. The roof insulation doesn't make the house warmer but it allows the central heating to make house warmer.

    Anyway, if this is the tosh that sceptics are coming up with I am beginning to wonder if the science isn't with the warmists after all.

    Also, what is with all this 'tree-rings' and 'temperature recording stations' stuff? Isn't that all just localised 'noise'. The real story should be pretty obvious from Earth's emission spectrum. Especially as there are some regular seasonal variations in CO2 levels.

    Why not just measure the emissions spectrum at a trough and then measure it at a peak ... then you will KNOW the sensitivty of global temperature to CO2 levels without all this complex modelling?


  6. Anonymous,

    1. Postma doesn't assume the Earth is a blackbody, he assumes it is a greybody. It's the GHE adherents who assume both the Earth AND the "ideal" gases in the atmosphere are both blackbodies.
    2. You say Earth radiates as much power as received, but fail to understand that GHE adherents claim LESS power is radiated than received due to the GHE
    3. Slowing of cooling does not cause warming

  7. Anonyomous,

    "Why not just measure the emissions spectrum at a trough and then measure it at a peak ... then you will KNOW the sensitivty of global temperature to CO2 levels without all this complex modelling?"

    A good question to be asking the Climate Scientists who have all the funding and most of the control on what the satellites and other experiments do. If it was so clear cut, why haven't they gathered the data in any number of ways to show us DENIERS how wrong we are???

    I would add that the Venus probes showed thermal fluxes way outside the EXPECTED range. They did this on FIVE SEPARATE MISSIONS and the OFFICIAL explanation was that they had similar malfunctions on EVERY MISSION!!! I may not be the most complimentary person on our space efforts, but, I don't believe even THEY could have gotten it this wrong FIVE TIMES without having a CONFIRMATION BIAS or similar problem in their ground work!!!