From: szabo@techbook.com (Nick Szabo)
Newsgroups: sci.environment,sci.geo.meteorology,sci.skeptic
Subject: Re: Lawyer's science vs. unbiased presentation of the facts
Date: 25 Jul 92 21:07:55 GMT
Organization: TECHbooks --- Public Access UNIX --- (503) 644-8135

In article <1992Jul24.184652.10374@meteor.wisc.edu> tobis@meteor.wisc.edu (Michael Tobis) writes:

>My final word for a while. I promise.

This is a weekly event.  :-)

>I mentioned that the likely global temperature at the end of the next century
>is higher than any seen in the last 30,000,000 years, 

No, you said CO2 levels will be the highest since 30 million years ago
(while continuing to ignore that they will still be far lower than
previous levels).  Our records for the last 30 million are too sparse
to make that statement for temperature.  Again, you make bald claims
without stating the numbers or reasoning behind them.

>and you continued
>to bring up rates of change in response.

Please reead what I wrote, and remember what you were writing.
You were arguing that global warming problems were unprecedented because 
of _rate of change_ before I raised these other examples, and suggested 
that magnitude is also important.

>Volcanoes and El Nino are somewhat off the subject, as their impact is
>brief in the first case and oscillatory in the second.

No, for determining ecosystem impact they are quite _on_ the subject.
Ecosystem impacts are caused by local, not global temperatures.

>* Keeping emissions constant at 1990 levels, as proposed by the treaty
>that most nations agreed to in Rio, yields a logistic increase in CO2
>concentrations, probably to about 420 ppmv, about 150% of the preindustrial
>level. Most analyses indicate that the changes due to such forcing will
>be noticeable, but not enormous. However, if emissions continue to grow by
>2%/yr until 2010, and are then held constant, total concentrations will
>continue to rise rapidly for the next century, reaching doubled levels by 2080,
>and asymptoting to about triple preindustrial concentrations in the 22d
>century. Thus, if clamping production is believed to be less economically
>injurious than drastically reducing it, rapid response is highly effective
>in limiting the final impact, whatever it might be. 

This analysis totally ignores the learning curve in switching
technologies, and is a good demonstration of why climatologists
should not pretend to be engineers or economists.  It is far
less economically destructive to first slow the increase in output
to zero over a period of 30 years, then if needed start reducing 
thereafter. Once we have fully functional substitutes there is no reason 
the level needs to be held "constant"; the greatest productivity gains
in technologies typically come _after_ the first thirty years of
widespread use.

By 2010, we will also have a much better idea of how much, if any, global 
warming will occur.  Therefore, it makes sense to study the climate now, 
and work on greenhouse-neutral energy and transportation tech now, and 
leave the large-scale carbon taxes to the next century, when we will have 
a much better idea of how much CO2 output reduction is needed, and a 
better idea of how to do it.

>* The anthropogenic forcing is large enough that significant climate
>change is inevitable,

You already pointed out that the albedo effects from increased
H2O are unpredictable.  One possible outcome is that the cloud 
reflectivity compensates for CO2 greenhouse effect, so that temperature 
change is not "inevitable".

>Local changes are certain to exceed
>global average changes (by definition of averaging)

Of course, local averages also exceed global averages today.
Greenhouse gases tend to _damp_ temperature extremes; 
for example water makes nights warmer and days cooler.

>If the worst case surface sensitivity holds and
>the worst case emissions continue, the results will be devastating. 

"Will"?  All you've described is temperature increase; that alone
is not at all devastating.  Secondary effects like weather pattern
changes, ecosystem impacts, glacial melts or buildups, sea volume 
increases, etc. may or may not be significant, even in the worst case.  
We already know that there are _benefits_ of CO2 itself, such as the 
fertilization effect which increases the productivity of agriculture 
and most ecosystems.

>The situation is such that anthropogenic emissions are just changing
>from insignificant to profound.

So much for the "smooth curve"; now we have a devastating quantum
leap.  :-) Tobis, this is what I mean by "hyperbole", if you were
wondering.  Some of your analysis is very good but then you descend
into this crap.


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