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From: eli@bbn.com (Steve Elias)
Newsgroups: talk.politics.misc,sci.misc
Subject: Re: the "greenhouse effect" theory
Message-ID: <22277@bbn.COM>
Date: 18 Mar 88 02:32:12 GMT
References: <22138@bbn.COM> <3851@bloom-beacon.MIT.EDU>
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Reply-To: eli@BBN.COM (Steve Elias)
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In article <3851@bloom-beacon.MIT.EDU> jfc@athena.mit.edu (John F Carr) writes:

!!	there is no valid model for the greenhouse effect.  

!I am not aware of any serious disagreement over the nature of the
!greenhouse effect, only its magnitude.

	the general nature of the effect is certainly agreed upon.
	i bet we could even find it in the dictionary! 

	but detailed models of any long-term atmospheric effect
	just aren't around yet.  you are a planetary scientist, right?
	do you admit that we don't have enough data to really be able
	to predict any planetary atmosphere?

	as a computer dude who has studied astronomy, i'll say that even if
	we did have enough data to learn how to predict atmospheres, we
	don't have .001 the processing power available to do the job.

!I called it a thermodynamic issue because the claim was that nuclear plants
!emit waste heat, and that this heat was important to the greenhouse effect.
!It can be proved (using thermodynamics) that ALL heat engines produce waste
!heat, so there is no justification in singling out nuclear power. 

	absolutely.  i'm singling out the greenhouse effect, not nuclear power.

!!	waste heat is not a global issue unless the energy for it originates
!!	outside the earth/atmosphere system.  that's the thermo concept
!!	i'm trying to stress.  the greatest thermal danger is from solar
!!	power satellites, or solar farms on earth.
!
!Waste heat from any of the heat engines (as opposed to hydroelectric,
!wind, or possibly trash [see below] power) is effectively from outside,
!since it would not otherwise have been released into the atmosphere on
!such a short timescale.

	exactement.

!JFC: However, chemical plants also produce carbon dioxide which does the real 
!JFC: harm to the heat balance by trapping IR radiation.

	thermal pollution could do real harm to the heat balance, too.
	especially if someone ever puts 'solar power stations' in orbit.

!My impression is that in extreme quantities either CO2 or heat can cause
!the effect, but that it is much harder to do with heat alone.  Think of
!CO2 as a catalyst, very small quantities of which can produce great effects.

	you bet.  enough heat could start thermal runaway, just as enough
	CO2 could.  i read in today's paper that the current guess about
	the extinction of the dinosaurs involves 3x to 5x increase in 
	atmospheric CO2 levels around the time they disappeared.

!(Thermal energy is spent heating up the earth, which would then cool on
!a timescale of days if it were removed. 

	i think John is doing some big time speculation here.
	massive amounts of thermal energy would not dissipate in a 
	matter of days.  (i mean thermal energy produced from power plants:
	if we produced 10x or 100x the power we do now.)  the Earth can
	only radiate energy at a specific rate -- sigma T^4, cloud cover,
	CO2 levels, and other stuff determines that rate.
	
	(John then goes on to show why trash or sewage fuel production
	 is not the answer to it all.  i brought up trash/garbage being
	 used to produce natural gas as a good example of a
	 "thermally correct :)" power source.)