A couple of points from Pharyngula:
* She repeats over and over that CO2 is a natural gas. Yes, we know…no one is claiming otherwise. (Also, what would an “unnatural” gas be, anyway?) Nitrogen is also a natural substance, it helps plants grow, and we produce perfectly natural nitrogenous materials from our bodies — so does that mean that we should stop sewer services and allow everyone to wallow in their poop?
* She claims that not one study has ever been produced to show that CO2 is harmful, and she goes further to claim that CO2 is a harmless gas. We could correct that in just a few minutes: give me a large tank of CO2 and a small room containing Michele Bachmann, and we’ll give her a personal experience.
* The atmosphere is 3% CO2? Is she really that ignorant? It’s more like 0.03%. And again, no one is arguing that CO2 is evil — it’s that its concentration has distinct effects on the temperature of the planet, and that concentration is changing.
See Also: The Express Train to Crazytown, Republican catechism vs science, Neocarbon, Replace Michele Bachmann, a bad week for science in politics, “Actually, we need more carbon emissions”, Bachmann-the-Nut, Scientist, Michele Bachmann: A Byproduct of Oxygen Deprivation, and Stark, Raving Mad.