I have often been frustrated with jopo's approach to discussion, but he does raise some interesting issues and I've used his questions to learn more. But as the science rebuts all the simple (and stupid) denial arguments the straw men now being created to argue the science are getting more complex. There's a bit more to understand, I think, about the ozone and greenhouse gas interaction in different parts of the atmosphere. Based on some of the science discussions and papers I came across it seems to me there are some valid questions the science is asking about that.
