Singer: 'I accept the theoretical existence of a greenhouse effect. In other words, I recognize carbon dioxide, water vapor, and other gases in the atmosphere can absorb infrared radiation and have a potential effect on climate. On the other hand, I am not convinced these effects really exist to any appreciable extent, so I am definitely not a lukewarmer.'
Dyson: 'There certainly is an enormous religion in which there are lots of true believers who think that climate change is evil and that we're going to run into big catastrophes if we don't do something drastic. That's a sort of belief system which exists...I don't understand it and I don't pretend to understand their motives.'
Salby: 'Because of the saturation effect in the energy absorption of CO2 molecules with increasing concentration and short residence time, the further increase in temperature could be therefore only at most a few tenths of a degree, if at all. However, the known fossil reserves would be exhausted by then.'
Laurence Tribe, a liberal constitutional scholar at Harvard University: “EPA possesses only the authority granted to it by Congress,” Tribe told lawmakers in a hearing Tuesday. “Its gambit here raises serious questions under the separation of powers… because EPA is attempting to exercise lawmaking power that belongs to Congress and judicial power that belongs to the federal courts.”