In article ,
says...
Again, note that I am
not saying that human activity cannot mess up local environments; ample
evidence for this exists. However, scaling that evidence to a global scale
is far from a proven fact.

I think that the scientific community is pretty heavily (95% vs 5% ??)
on the side of human causation of at least a great deal of the global
warming.

But you're right, there is no absolute proof. But can we afford to wait
till there is?

And it is pretty well established that human produced CFCs are
responsible for the loss of some of the protective ozone layer. That's
pretty global :-).

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BNSF = Build Now, Seep Forever