You brought up Randi, so let's see what he has to say:
As I've indicated, I do not deny the finding of GW. AGW, to me, is less clear, though I accept that it is likely true.
"While we are both amateurs, I think it behooves us to give in to those who have devoted their professional lives to understanding this complex subject. And what they have to say can be boiled down to this: the world is warming and humankind is responsible for at least half of that rise in global average temperatures."
Accepted.
http://www.randi.org/site/index.php/swift-blog/806-i-am-not-qdenyingq-anything.htmlWhat's that? Even the most famous skeptic of the modern era is of the belief that global warming is a phenomenon that actually exists, which many here refuse to believe is even happening, instead perversely arguing that the global average temperature is decreasing. Not only that, but in his own words "AGW ... is likely true".