I'll go along with you here. I also don't think there's enough evidence to say we are the sole cause. The problem is far too complex to say that. There are things we still don't know about the climate and what effects certain things have upon it.
But I also feel that the evidence FOR global warming is strong, and the evidence that our CO2 emissions are adding to the problem is just as strong. Doing something about that is in all of our interests. Letting governments take the lead, though, is suicidal.