I very much doubt that early proponent of fission-powered electricity in France or anywhere else had CO₂ concerns in mind, but countries who made that choice certainly ensured a much less dramatic energetic transition circa now.

That's my problem with anti-nuclear people: the problems of nuclear waste are largely anecdotal for now, it would only become a real concern centuries down the road (and even that's debatable), while CO₂ is rising and that's an immediate, pressing concern.

So building a few nuclear reactors now to curb CO₂ emissions is definitely the way to go if we intend to keep on increasing energy levels (thus not F up the economy too much to combat climate change); whereas favoring windmill and solar too fast too soon is just bad use of our short-term budgets (both in time and money): we'd better for instance invest massively in electric infrastructure to replace all trucks (eventually all vehicules, but again, urgency and magnitude set the order).

I mean, isn't it idealistic and dangerous to say 'no' to nuclear now when our immediate concern is CO₂, greenhouse effect? I'd rather see 2100 with as little temperature increase as possible with a little bit more nuclear waste (that would be of no effect to anyone), than the opposite (because the former paints a non-catastrophic picture, whereas the latter is potentially apocalyptic for some regions and major cities of the globe).

In this specific case however (France, Fessenheim and the other), these were too old reactors and needed shutdown, it was unsafe to keep them going. The last thing we need in this world right now is France failing at nuclear safety.