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Re: fHuman vs. natural influences on the environment
In article <4u3avt$su3@condor.ic.net>,
All locked up and nowhere to go <cage@critech.com> wrote:
>charliew@hal-pc.org (charliew) wrote:
>>So what? There is no big revelation here that a very
large
>>system (the atmosphere) has a long process time constant
(it
>>takes a long time to see a change). This idea is common
>>knowledge to any process control engineer.
>
>It is common knowledge to any process-control engineer that
>a system reacts little to forcing functions above its
cutoff
>frequency.
>
>The observation that the atmosphere reacts very
substantially
>to a forcing function with a period of 1 year proves that
the
>"long process time constant" is short even on human time
scales.
>
>> What about the
>>fact that this long response time can also be beneficial
in
>>that sudden disturbances may have little or no impact?
>
>This one sentence contains several faulty assumptions. To
>list a few:
>
>1.) It assumes the disturbance is a delta function which
is
> never repeated. A more accurate model would be a ramp
> function.
>
>2.) It assumes that the response time is long compared to
> the duration of the disturbance. See above.
>
>3.) It assumes that the system is linear and stable. The
> best data to date suggests that it is chaotic.
>
>
Oh, gee. Another guy in the world who knows something about
process control!
I made no assumptions in my statements. I was trying to
point out that a long time constant by itself is not
necessarily detrimental. Whether a system as large as the
atmosphere can be substantially affected over a 1 year time
interval is open to debate, and something that I consider to
be merely a matter of your opinion. However, even if I
assume that this is true, a time constant this short implies
that we can also move the atmosphere an equal amount in the
opposite direction in the same 1 year period. So, where's
the problem here?
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