Myself, I'm undecided on man-made CO2. I think there's some straight-forward research that can be done, but ordinarily scientists argue in that useless way of pointing out what's wrong with the counter-theories, without providing real proof of their own theories. We're left with scientists trying to prove themselves right rather than find the truth, and every so often keep offering contradictory information. But then this doesn't affect my ecological stance, because I believe in not wasting anything anyway and a symbiotic relationship with the world. Whether manmade global warming is an issue or not, I'll still cycle to work and switch off lights and not leave electrical appliances on standby on principle.