From wmc@unixa.nerc-keyworth.ac.uk (William Connolley)
Newsgroups: sci.environment
Subject: Cooling; was: Re: CFCs in the atmosphere (was Re: Why do
Date: 25 Jan 1996 17:36:02 GMT

In article 3ss@news2.delphi.com, arussell@BIX.com (Andrew Russell) writes:
>Dean Myerson wrote:
>>As I remember, Newsweek and Time predicted global cooling.  Are you
>>aware of any climatologists, or peer-reviewed articles in general,
>>that predicted global cooling?

>Try Steven Schneider:
>
>  1971, in the July 9 issue of Science: "Temperatures do not 
>  increase in proportion to an atmoshperic increase in CO2.  
>  Even and eight-fold increase over present levels might warm 
>  earth's surface less than 2 degrees Centigrade, and this is 
>  highly unlikely in the next several thousand years."  He also 
>  said in the article that quadrupling aerosols "could decrease 
>  the mean surface temperature (of Earth) by as much as 3.5 
>  degrees K.  If sustained over a period of several years, such a 
>  temperature decrease could be sufficient to trigger an ice age!"

>Andrew Russell

This is a much better try than any previous efforts, but is still a clear failure.
The game was, find a reference that *predicts* "a new ice age" "immenently" or if
you can't do that, find a reference to *predict* global cooling. This reference,
as quoted above, makes no predictions at all about Earths future climate, but does 
predict the response of the climate to a postulated increase in aerosols or CO2.

There are some other interesting points about the article itself, which are noted in
the article:
1. the temperature increase with CO2 found is about 1/3 of Manabe and Wetherald.
This is accounted for by different CO2 abs coeffs, different lapse rate specs,
and different CO2/H20 overlaps.
2. The model used is a 1-d model lacking many feedbacks (eg, ice-albedo). The 
authors point out that the model is applicable to *small* changes in single
parameters. They do not point out that 8*CO2 or 4*aerosol depth are not small changes.

The title of the article itself is "Atmospheric Carbon Dioxide and Aerosols:
effects of Large increases on Global Climate", which suggests (correctly) that the
article is a sensitivity study for large changes rather than a prediction for
expected changes.

Fans of exact quotation accuracy may like to know that the "quote" AR gives above is
not found word-for-word in the paper, but is essentially accurate (including the
perhaps rather unfortunate "!").

---
William M Connolley | wmc@bas.ac.uk | http://www.nbs.ac.uk/public/icd/wmc/
Climate Modeller, British Antarctic Survey | Disclaimer: I speak for myself