From: rdonahue@spdcc.com (Bob Donahue)
Newsgroups: soc.motss
Subject: Re: H20, Greehouse, meteorology (was Re: kommotion...)
Date: 11 Jan 93 18:03:21 GMT
Article-I.D.: spdcc.1993Jan11.180321.7179
Organization: insert anything here

mls@panix.com (Michael Siemon) writes:
>jfh@netcom.com (Jack Hamilton) writes:
>>rdonahue@spdcc.com (Bob Donahue) writes:
>>>In article <C0ns5p.Do4@panix.com> mls@panix.com (Michael Siemon) writes:

>>>	[asks questions about solar irradiance variations and their
>>>effect ont he solar-terrestrial interaction...]
>>>
>>>	Yeah, I took it to e-amil... :-)

>>Too bad.  I was interested in the answer to that. 
>Actually, I wasn't asking about irradiance variations (though that is
>relevant and I'd like information in addition to the Milakovitch work
>on correlating our orbital element variations with glacial cycles).
>The relevance to my remarks is that *if* insolation differences drive
>the temperature cycle, and water vapor in the atmostphere cycles in
>response to this, it is unclear what the relation of ANY greenhouse
>gasses might be in the long term.  Do either or both of H2O or CO2
>*moderate* the Milankovitch cycles? exaggerate them? what?

	As to that I'm not sure --- I deal in much shorter timescale
behavior --- only a few hundred as opposed to thousands of years :-)
I think for the most part it's still a very open question.
The hard part of course is finding some kind of proxy that lets
you measure the temperature variations *and* several possible
causes for it.  The Milkovitch stuff is useful because it only relies
on the assumption that orbital element variations are stable over
long periods of time - which probably isn't too bad.

	The other problem is the chicken or the egg sort of thing:
do temperature variations influence the climate or does the
climate induce the vcariations?  If you believe the current greenhouse
model you have to find a mechanism that makes the temperature go up
before the CO2 does (oops).  Most of the models as I said before
treats the Sun as a constant light-bulb, on the short term
as well as on the extremely long-term.  I'm certain that the former isn't
correct, and that implies the latter isn't either.  But we simply
don't have that detailed a record to talk about what might occur on 
the 10000-year level.

	right now I have about a dozen stars that are like the Sun 
more or less yet half show a pattern of rotation that is compeltely 
back-asswards - that suggest to me that one of two things is probably
the reason: 1) a dice roll in stellar adolescence or 2) a flipping
that occurs one or more times over a star's life at some unknown
timescale --- I checked 17th century data --- and came up empty
handed so I expect it's longer than a few hundred years.  Since
these stars are all more than 2,000,000,000 years old there's a
LOT of time to play with --- the only way to be sure is to catch
one in the act twice, and I think that I'm not going to live to see it :-)

	The other question that comes to mind is wondering how
long it takes to change the constituency of the atmosphere.
Certainly this mix hasn't always been like this - all most people will say is
"oh, millions of years" mostly because the Earth is so old and 
it's a great stab in the dark.

	The short answer: I don't thinkk anyone knows for sure.

>Bob may be right that soc.motss is not a good place for this --
>perhaps we move it to sci.geology or sci.astro?  (again, I am
>NOT doing this out of a political agenda or to controvert BBC's
>political stance -- I would need more information to *have* an
>informed opinion on all of this.)


>-- 
>Michael L. Siemon	"We honour founders of these starving cities
>mls@panix.com		 Whose honour is the image of our sorrow ...
>			 They built by rivers and at night the water
>			 Running past the windows comforted their sorrow."
Newsgroups: soc.motss