In almost all explanations of the greenhouse effect, it is somehow claimed that greenhouse gases (GHG) absorb IR radiation and therefore must heat up the atmosphere. Then, because of the heating up, the atmosphere will also radiate back more energy to the surface and heat it up.
I think that is a wrong representation of what happens.

Radiation effect of GHG
Let’s consider a volume of air that receives radiation from the earth’s surface, which has reached thermal equilibrium state. The temperature has reached a value (Teq) at which all absorbed energy is radiated out again, of course in all directions.

If we now double the amount of GHG in the volume, the added molecules will receive the same amount of radiation, so they will also end up at Teq, at which they emit as much energy as they absorb. Increasing the GHG concentration does not affect Teq.
It does increase back radiation, so when the volume is close to the surface, it will heat up that surface, as we have easily quantified in our simulation. But the air temperature will remain the same, i.c. Teq. So there is no warming of the volume.

Saturation
When the GHG concentration reaches GHG sensitive IR saturation levels, an increase of GHG no longer increases the amount of absorbed IR, while the emission still increases linearly. This disturbs the equilibrium, so the temperature has to drop.

Therefore increasing GHG concentration does not heat up the atmosphere directly. If GH gases change temperature at all, they cool it down. But they still do warm the surface by an increase of re-radiation, even if they cool down the air.       (more…)

In order to explain the physics of the greenhouse effect, it is often proposed that it works in the following way:

Standard greenhouse physics

Because, with an increase in CO2 concentration in the atmosphere, there are more CO2 greenhouse molecules in the tropopause, they will radiate into space from a higher level (from Ze to Ze + ΔZe). Because of the adiabatic lapse rate, it will be colder there, so they will radiate (a lot!) less energy to space.
This disturbs the equilibrium, so in order to restore that, the earth surface has to heat up (from Ts to Ts + ΔTs), so the adiabatic lapse rate (ALR) will move upwards and warm the tropopause, until the radiation into space is the same as before the CO2 increase. In the drawings this theory is always illustrated with beautifully straight lines.

This explanation seems quite logical, and many adhere to it. But I think I can prove that the logic behind it is flawed.

Wrong assumption
The flaw of the theory is that it contains a hidden assumption that is not correct.
It assumes that the energy that is absorbed at the surface, is transported to the tropopause by the rising air folowing the lapse rate, and is emitted to space from there. (more…)

One of the assumptions about the way latent heat is radiated into space, is “deep convection”. Like the standard greenhouse theory that was described in chapter 9, this suggests that the main radiation into space is from high in the atmosphere, near or even above the tropopause.

I have always had my doubts about that. As discussed in chapter 9 there is hardly any water vapour and a very low concentration of CO2 at that height, and temperatures are extremely low.  With radiation decreasing with the 4th power of the temperature, how can so much energy be disposed of, with so few GHG molecules, at so low temperatures?
I expected that lower parts of the atmosphere would be more important, even for the emission of the energy from deep convection to space. But it was not easy to quantify that without modelling the Hadley Cycle, which is powering most of the latent heat transport (LHT). Still I decided to give it a try, as a showcase of what my Fireworks simulation could do, if provided with the right data by experts.

The Hadley Cells: the worlds cooling engine
As Willis Eschenbach explained so clearly in his presentation at the ICCC4 in 2010, the earth might have a powerful thermostat, consisting of the tenthousands of daily tropical thunderstorms.

They are part of the Hadley cells and transport enormous amounts of latent heat to the tropopause. In the theory of Eschenbach they compensate the radiative effects of greenhouse gas concentration changes, and probably have done so for billions of years.
But how does this Hadley cell actually work? What really drives it, and how does that relate to the standard explanation of the greenhouse effect?    (more…)