[GonzoGOP]

But whatever it chooses to do, it won’t be because of CO2.

At least not at the atmospheric levels that they are talking about. Sure if you go to Venus where the atmosphere is 96.5% CO2 you are going to get some serious greenhouse effect. But Earth's CO2 level is 0.038%. Double it to 0.076% and it would still be below a rounding error on Venus.

[pieceofthepuzzle]

Truth in science (and other venues of society) progresses generally due to the cumulative contributions of honest and diligent scientists who do the non-glamorous reproducible work. Glamor seeking celebrity scientists like James Hansen are generally a distraction and ultimately don’t make very substantive contributions, despite the amount of grant money they get, the number of countries they visit for academic conferences and seminars, the number of times they are on TV, and the cost of the tax-deductible wine they drink at their meetings.

[palmer]

Sure if you go to Venus where the atmosphere is 96.5% CO2 you are going to get some serious greenhouse effect. But Earth's CO2 level is 0.038%. Double it to 0.076% and it would still be below a rounding error on Venus.

No it is more or less the opposite. Here on earth the first 5 ppm of CO2 have a very large effect. Each subsequent 5 ppm adds an exponentially diminishing amount of warming. That's why increases here on earth are not a problem, not only does CO2 itself have less of an effect, the water cycle will accelerate and cause cooling.