Then you gotta like this quote from the transcript:
“The earth’s climate really is strongly affected by the greenhouse effect, although the physics is not the same as that which makes real, glassed-in greenhouses work. Without greenhouse warming, the earth would be much too cold to sustain its current abundance of life. However, at least 90% of greenhouse warming is due to water vapor and clouds. 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. Additional increments of CO2 will cause relatively less direct warming because we already have so much CO2 in the atmosphere that it has blocked most of the infrared radiation that it can.”
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.