Global Cooling Apr 7, 2009 4:14:41 GMT
Post by icefisher on Apr 7, 2009 4:14:41 GMT
I had to go back and read your original post on the electrical analogy, but I'll give it a shot.
In electrical circuits, if two or more resistances are placed in parallel, the total resistance is then the inverse of the sum of the inverses. ie, 1 / (1/r-1 + 1/r-2 +1/r-3....).
In the GHG world, this would mean that more IR is passed (not absorbed) than would be due to any one concentration area.
(Do I have the analogy correct?).
I don't believe this would apply as the GHG does not present a resistance to the passage of photons. If the conditons are right, the molecule may absorb, or remove, a photon from the IR flux leaving the background. It may then re-emit a photon of equal or lesser value in any direction.
The Greenhouse theory says that since 50% of those photons will be sent back from whence they came, this will reduce the rate at which energy is lost or add energy to the emitter (earth), making the earth warmer.
A warmed molecule of CO2 though emitting in all directions will need will emit sufficient photons to maintain an equilibrium.
Photons being emitted back at earth don't count.
Lets face it atoms at the surface of the earth at temperature X are emitting Y photons from half its surface.
The GHG absorbs Y-Z (Z being the IR the GHG is transparent to) and in turn on half its surface towards space emits Y-Z after obtaining the correct temperature to do so.
Trying to account for photons the GHG might be emitting back to earth is a futile exercise that merely makes the problem unnecessarily complex whether or not there is such an effect (keep in mind the whole process is an abstraction anyway and it does not matter cause there is no place for this additional heat to hide in the system). Heat in always equals heat out.