Re: [asa] Creation Care

--- Rich Blinne <rich.blinne@gmail.com> wrote:

> On 1/24/07, Bill Hamilton <williamehamiltonjr@yahoo.com> wrote:
> >
> >
> > I agree that the hardware -- and the software -- for modeling have
> > improved
> > significantly. And that allows us to model more effects that we used
> > heuristics
> > for before. But climate models are still complex enough that if we miss
> > anything, all the increased capability will do will be to enable us to
> > produce
> > garbage much faster. And I suspect that it's easy to miss effects in
> > climatological models. Since the models are validated by comparison with
> > historical data, an effect that shows up outside the time baseline may be
> > missed. And given the chaotic nature of weather, _any_ omission --
> > dynamical or
> > boundary condition -- is likely to cause significant departure from the
> > true
> > behavior.
>
>
> It is not the case that _any_ omission will cause a problem. A helpful
> analog comes from control theory because you can view the climate a series
> of positive and negative feedbacks. The question that is most at issue --
> and cannot be computed because the system is too complicated -- what is the
> Nyquist stability of the "system"? A classical example of an unstable
> system is microphone feedback. You cannot eliminate positive feedback so
> electrical engineers add negative feedback into the system to stabilize it.
> An unstable system is sometimes referred to in the popular press as a
> "tipping point".

As one who has a Ph.D. in control theory -- and worked in machine tool and
robot control for ten years -- I think you seem pretty sanguine about climate
dynamics. My point is not that we shouldn't try to model the climate, just that
we should be cautious in making long term predictions from the results, and we
should be cautious about prescribing expensive remediation programs.
>

Bill Hamilton
William E. Hamilton, Jr., Ph.D.
248.652.4148 (home) 248.821.8156 (mobile)
"...If God is for us, who is against us?" Rom 8:31

 
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Received on Thu Jan 25 17:01:52 2007