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Re: Human vs. natural influences on the environment



In article <32285817.58EB6303@math.nwu.edu>,
Leonard Evens  <len@math.nwu.edu> wrote:
[trimmed]

>The point made by Santer and his colleagues in the
>detection chapter (8) of Climate Change, 1995 is that this is now at the
>level where we can say with confidence that human activities have
>affected climate but the uncertainties are still too large to quantify
>the human contribution.   

You seem to be reading more into Chapter 8 than is there.  Quoting from 
a passage:

"...few would be willing to argue that *completely unambiguous* 
attribution of (all or part of) this change has already occurred, or 
was likely to happen in the next few years.  However, evidence from the 
pattern-based studies reported on here *suggests* [emphasis mine] that 
*an initial step* [emphasis mine] has now been taken in the direction 
of attribution..."

[Climate Change 1995]

This does not seem to equate to "we can say with confidence that human 
activities have affected climate..."  Rather, an initial step towards 
such attribution is suggested by the studies.

Contending that something has caused something is a bit tricky when one 
cannot put a lower bound (even of epsilon) on the magnitude of the 
effect.  The authors are appropriately cautious.

>Leonard Evens       len@math.nwu.edu      491-5537

snark



References: