[palmer]

Carbon dioxide is a bit player. There is little argument in the scientific community that a direct effect of doubling the CO2 concentration will be a small increase of the earth’s temperature — on the order of one degree

The first sentence can easily be misinterpreted. Without CO2 the earth would be a ball of ice with an average atmospheric temperature of -18C (instead of 15C) The second sentence is correct and well worth emphasizing. The same water vapor feedback that makes CO2 changes modest is what makes CO2 essential to begin with, the two go hand in hand.

[Delacon]

Well I think he is trying the emphasize the fact that we have pretty much wrung out all the global warming potential from CO2 unless all these positive feedbacks that are supposed to affect water vapor come into play. As I understand it, almost as bad a vacuum, nature abhors a positive feedback. Correct me if I am wrong. I ain't no scientist.