To claim that these processes are governed by human activity is the height of narcissism or stupidity.
But to ask questions about it certainly doesn't do any damage, does it?
Is it there? How much if anything is caused by man? How should we deal with it, if at all? What effects would Kyoto have?
Reasoned enquiry is seldom negative IMHO.
Do you think Lomborg is a leftist kook for working on these issues?
Cheers.