This is a little gem I’ve got to share. Apparently not only have academics been daft enough to call the original effect the “Greenhouse effect” – when greenhouses work in completely different ways, but they’ve gone as far as to name something the “anti-greenhouse effect” – thus proving that the name “Greenhouse effect” is a total load of codswallopLike most sceptics I think greenhouses are things for growing vegetables in and that its an absurd name to use for a scientific effect that works in an entirely different way to a greenhouse.
Instead of trapping hot air (as greenhouses work) the actual effect of IRAG (IR Active Gases) is very different. To put it simply: if we imagine a uniform temperature planet with a single IR Active molecule in its atmosphere:
If the surface area of the planet is Sp and that of the molecule is Sm, the temperature of the planet is Tp and that of the molecule is Tm then the average temperature as seen from space will be:
T = ((Sp – Sm) Tp4 + Sm Tm4)0.25
Or to put it simply, if Tm < Tp (molecule colder than surface) then the temperature as seen from space will be lower – and a lower temperature means less radiation to space so a warmer surface.
If Tm>Tp (molecule warmer than surface) then the converse: the average temperature as seen from space will be higher and the radiation is higher, so more cooling and a colder surface will result.
Note, the key thing controlling whether there is warming or cooling, is not the concentration of the IRAG, but the temperature of the IRAG with respect to the surface.
That’s the simple physics. The only additional problem is having some from of energy flow to maintain the temperature of the molecule in the atmosphere. For a colder atmosphere this is simple to explain, because the lost heat drives convection which then delivers heat energy and the lapse rate determines the temperature.
The opposite is less easy to explain, because for IRAG cooling you need to have a warmer atmospheric temperature than the surface. This occurs very high up in the earth’s atmosphere but the warming is due to incoming solar radiation. Now the cooling process is not from the earth’s warmer temperature being blocked out by a colder IRAG molecule but because the (relatively) cooler IRAG is blocking out the hotter sun. But now all pretence at the greenhouse analogy completely breaks down – because the earth isn’t making the sun anywarmer.
The key thing is not what the effect is, so much as if you refer to IR Active Gases it makes sense that you can get warming or cooling depending on the IRAG gas temperature – with cooler atmospheres being the norm so IRAGs normally cause warming. But it never occurred to me anyone would be as stupid – first to refer to the falsely named greenhouse effect, and then to call the cooling effect the “anti-greenhouse effect”.
But apparently they did (Screenshot because almost invariably when sceptics find a gem like this, it quickly gets “disappeared” by the team).
The main place I’ve found this being discussed is on Pluto (I went there for a weekend 🙂
So, with all the debate about “back heating” will we now start hearing similarly emphatic debates about “Back cooling” (LOL)