We can debate whether or not… CO₂ does or does not contribute to global warming. I think the jury is out.
~ Stephen Harper (born: 1959-04-30 age: 52) anti-environmental Prime Minister of interview on the Rafe Mair Show, CKNW Radio Vancouver, 2002-11-29

That is simply not true. Harper is parroting FUD (Fear Uncertainty and Doubt) put out by big oil. Back in 1824 Fourier discovered the greenhouse effect (when Marx was still only 6 years old). Svante Arrhenius, the great Swedish chemist published his calculations in 1896 about how atmospheric CO₂ concentrations control the average global temperature, and how certain amount of CO₂ was needed to prevent an ice age.