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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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