>I suppose its true that we don't know what the consequences of these things
>will be since the earth is a very complicated system. But this seems to me
>an argument against changing the environment, since any changes we induce
>will probably be unpleasant.
Why? Most of the changes induced so far have made the world more suitable to human life, as proved by the increase in population and life expectancy. The existence of a "Golden Age" is a myth, and a deeply reactionary one.