[net.space] Greenhouse effect

giles@ucf-cs.UUCP (Bruce Giles) (11/26/83)

Maybe I've missed something somewhere (although some may claim it is
between my ears -- I've still fazed by that ABM discussion :-)), but
I am getting somewhat comfused by the greenhouse effect.


As I understand it, the earth's atmosphere will pass visible light.
(no problems there).

The earth (and atmosphere) absorb this light, is heated by same process,
and reradiates energy somewhat like a black body (no problems there,
either).

The atmosphere is now opaque to the IR radiation, so the energy can
not be reradiated *directly* back into space.  (I'll accept as a working
condition; I know in that Florida it is far cooler in the winter when
the sky is clear compared to when it is overcast, but there may be
other phenomena involved).

But -- What keeps the atmosphere *as a whole* from being heated by 
thermal conduction, convenction (sp?), phase change, -- whatever --,
and reradiating this energy from the upper atmosphere?  After all,
the earth *must* obey the laws of thermodynamics, and if you pour
extra energy into the earth, does not that raise the effective temp-
erature of the earth as a whole?  And will not that cause the earth
to act as a slightly warmer black body itself?

In other words, are there not indirect ways of reradiating the energy
into space, which may affect the weather distributions but *not* the 
mean tempature?

[sidenote -- there was an article in an *Analog* a few months back on
	     this topic, but I felt too many things were left out.
	     Basically, the author seemed to treat the earth as a 
	     perfect black body, and I want to see climatic effects
	     taken into account also.  Things like changes in the 
	     composition of the atmosphere due to a change in the
	     composition of dissolved gases in the seawater.]


			    Bruce Giles
			    decvax!ucf-cs!giles (UUCP)
			    UCF, Dept of Math, Orlando Fl 32816 (Snail)