R gates
I disagree with your comparison to teens smoking. In that case there are undisputed harms to the individuals.
In the case of emitting CO2, the are definate benefits that come about from the use of fossil fuels (concrete, fertilizers, electricity, personal mobility, etc); but the net harms are not proven at all. In fact, it is probably easier to argue that the idea that there are net harms are little more than wild speculation and a large percentage of the feared harms seem to be getting shown to be unfounded fears.