From rmg3@access2.digex.net Thu Jul 24 14:38:45 EDT 1997
Article: 36802 of sci.geo.meteorology
Path: news2.digex.net!digex.net!not-for-mail
From: rmg3@access2.digex.net (Robert Grumbine)
Newsgroups: sci.geo.meteorology
Subject: Re: More on the Global Warming debate
Date: 24 Jul 1997 14:35:23 -0400
Organization: Under construction
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References: <5p9opn$bou@nnrp4.farm.idt.net>   <33D78E36.6039@alaska.net>
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Xref: news2.digex.net sci.geo.meteorology:36802

In article <33D78E36.6039@alaska.net>,
Charles Samuels   wrote:
>The most dominant feature of long term world climate is recuring ice
>ages.  As I remember they recur at about 13,000 year intervals and we
>are in a period between ice ages.  

  The warm intervals themselves are 10-20 thousand years long.  We're
about 10 thousand years in to the current one, which (if humans hadn't
changed parts of the climate system) would be expected to last another
10 thousand years.

  The period of the ice ages themselves, warm peak to warm peak, 
has been about 100,000 years.

>Their are a number of questions that
>have never been answered, such as "what causes them?" and "how warm does
>it get in the warming period?

  The latter question is pretty well answered -- about this warm.  'This'
being the climate of the last 10,000 years.

  The former question, we have some very good ideas.

>If history repeats, we should be worrying about cooling not warming.

  Only if you think in terms of thousands of years in your planning,
and ignore that we've already made first order changes to the climate 
system.


-- 
Robert Grumbine rmg3@access.digex.net
Sagredo (Galileo Galilei) "You present these recondite matters with too much 
evidence and ease; this great facility makes them less appreciated than they 
would be had they been presented in a more abstruse manner." Two New Sciences