Listening to both sides of the argument here it sounds like one side is saying need more data and the other is saying we have enough. Regardless, why play a crapshoot with exceptionally slow moving systems just to prove a point? That's the Exxon approach because they are making a ton of bucks with the current plan. The only changeable variable here is human behavior and activity. Seems like a hell of a gamble to play chicken with nature and just deny that there is a possibility that the current trend is manmade. We can create new economies removed from fossil based energy, but we do not have it in our power to reverse earth scale systems quickly if we have made the wrong assumptions.