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Re: Human vs. natural influences on the environment



All locked up and nowhere to go <cage@critech.com> wrote:
>charliew@hal-pc.org (charliew) wrote:
>>Let's get real here.  How many things in nature have 
>>positive feedback loops associated with them?  Not many.
>
>Climate is one of them.  The Earth's climate has at least
>two metastable states (glaciated and temperate), and may have
>more on the hotter side of temperate.  Changes between them
>appear to be driven by short-term positive feedback and long-term
>negative feedback, forced by inputs such as orbital and axial
>variations.

<snip>

>Until we know where these thresholds are for Earth's climate,
>we ought to be careful about how far we push it.  It may turn
>out that the system is stable albeit a bit warmer at 1000 ppm
>CO2, in which case we have little to worry about.  It may turn
>out that at 770 ppm CO2 the system acquires a new metastable
>state where tropical conditions prevail up to the 40th parallel,
>and a good disturbance can push the system over.
>
>We don't know.  We should be careful what we do until we do.
>
>Is that enough of an antidote to "chicken little" for you?

Nice reply.  The simple fact is that if scientists proposed
what we are doing to the atmosphere today as an experiment, it
would be banned as far too risky to human health and safety.

Tom Gray
Director of Communications
American Wind Energy Association

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-----------------------------------------------------------------
Tom Gray <tomgray@econet.org>




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