I know you didn't want to say that, but it sounds like cars didn't produce CO2 when they were still polluting the environment in heavy ways with sulfur, and many other things. And I agree that any alternative will also come with its own problems.
For me the real problem is not the particular energy we use to do what we do, but the sheer amount we use for that. No matter how you will get at that energy it will have sooner or later some impact on our environment. There can be variations in how dangerous or polluting that energy is, but I do not believe that there is any energy source that will not have some negative impacts on us if consumed in the amounts we currently do. And then to think that almost 1/2 of the human population is in fact in so called upcoming economies that strive seem to go to have the same energy consumption that we have!