Ongoing shittiness is predictable and easy to understand. We've survived so far, surely we can survive if it gets just a little worse. Big disasters are unpredictable and hard to understand. One of those could end the world at any time. AFAICT that's the whole reason people are more afraid of them.
> Big disasters are unpredictable and hard to understand. One of those could end the world at any time.
In the context of nuclear reactors, Fukushima and Chernobyl are pretty much the worst case scenario. A large nuclear disaster is very disruptive to the immediate area but it would not "end the world" in any sense.
I'm pessimistic but the only way that can end the world is if we really want to. It would be very similar to a nuclear war. At some point you have caused so much damage there is no point in further fighting. The only reason why the world would end at that point is that the remaining people want it to end at all costs.