re: #103 zephirus

Without an atmosphere, the zeroth order energy balance for a planet is

Total incoming shortwave (solar) energy = Total outgoing terrestrial energy radiated in the IR. In this case the temperature would remain constant. It is easily computed, and is one of the first problems I assign to students.

It is true that E=hv (h=Plank’s constant, v=frequency) for individual photons. Total energy = number of photons x energy per photon. It is the total integrated radiance that is relevant. The energy of an individual photon is not relevant.

With an atmosphere that contains molecular species that absorb in the 1-10 micron range (IR), such as CO2, the outgoing radiation is intercepted and re-radiated back to the surface instead of escaping to space. These chemical constituents do not absorb (much) in the visible region of the spectrum. The energy balance is now

Incoming solar energy = outgoing IR + energy that goes into warming earth’s surface+atmosphere

The second term above —> increase in temperature

Ludwig is largely right …we could also discuss the nature of blackbody radiation, etc. but I don’t want to get too technical here.

Mkelly, continue to explore your ideas, but keep in mind that a little knowledge can be dangerous, and trick you into thinking that you know more than you do. Those who know the most are humble because they realize all that they do not know.

Excellent post but I was “largely right”?

;)

Black body radiation is a no go with these folks because they have picked up the meme that misusing words from Quantum Mechanics or particularly Thermodynamics makes them sound almost scientific to their peers.

If you read his post carefully, you will see that it is a misunderstanding of black body radiation that caused him to have such confused ideas. My point to you respectfully is that if they do not get energy conservation don’t bother with more moving parts that are not the dominant effect anyway.

We really do not need to invoke it. For the cognoscenti, it is implied in the discussion that the dominant effect to worry about is re-radiation from CO2 and absorption on the Earth. If you want to talk about thermal radiation - much of it in the IR, it gets reabsorbed and re scattered the more CO2 and water vapor you have.