On Feb 26, 10:29 pm, (Øyvind Seland) wrote:
In article .com, writes:
Would not extra atmospheric carbon dioxide increase the efficiency of
the Hadley, Ferrel, and Polar cells in cooling the earth's surface by
causing the upper troposphere to radiate better?

To be more specific, say the tradewinds blow across the heated ocean.
Evaporation occurs, cooling the ocean. A thunderstorm, front, or
cyclone happens, precipation occurs, the air is heated, and rises. In
the upper troposphere it cools, before descending to complete the
cycle. However it can only cool because it contains carbon dioxide, as
oxygen, nitrogen, if they do not absorb, neither shall they emit
radiation. This presumes that water vapor is insignificant at these
elevated altitudes. If the CO2 is increased by a large fraction, then
the radiation should be similarly enhanced.

Obviously I am out on my own with this analysis. I'm curious why it's
wrong though.

There are no physical law demanding that material has to absorb radiation
in order to emit. It has to emit if it is absorbing.

CO2 transfer energy to N2 and O2 by molecular collisions.

Øyvind Seland

So how do the N2 and O2 lose that energy? By colliding with CO2 [and
clouds according to the second poster] which radiate it. If a layer of
gas is to lose energy by radiation, it needs a radiator, no?

Quote from my uni textbook, "Principles of heat transfer", by Frank
Keith, 3ed, section 5-8 Radiation properties of gases and vapors
" Elementary gases such as O2, N2, H2, and dry air have a symmetric
molecular structure and neither emit nor absorb radiation unless they
are heated to extremely high temperatures at which they become ionized
plasmas and at which electronic energy transformations occur. On the
other hand, gases which have polar molecular forms with an electronic
moment such as a dipole or quadrupole absorb and emit radiation in
limited spectral ranges called bands. In practice, the most important
of these gases are H2O, CO2, CO, SO2, NH3, and the hydrocarbons."

This suggest to me that O2 and N2 cannot emit radiation, so must
collide with CO2, H2O, or a cloud to lose energy.
Cheers,
Peter Garrone