Originally Posted by Zloth
Climate change wouldn't be likely to end the world, IMHO. Mass extinction, sure, but I expect a little of humanity will find a way to adapt in some part of the world even in the worst case scenarios.

I would say this to a nuclear war.
Climate change has the potential to start becoming worse by itself, by speeding itself up (albedo, and maybe Release of methan, but that's under debate).

A nuclear war…well. Sure 99.9% of all pupulation will die. But we are tons of humans, and some will survive in bunkers and whatnot. And even if the majority of births of new generations fail, some will make it. I find it very likely that a nuclear war will wipe us out completely. It's more like a roguelite where you die and then start again with better starting conditions (not because the world is radiated, but because you keep lots of your knowledge).

I remember something about plastics but also air pollution affecting fertility. So I voted ‘pollution’. I don’t see that problem diminishing any time soon. The tiny particles that are everywhere nowadays - the Artics, deep sea, air - come to mind.
Also, they keep on using completely new materials, without having a clue what the long term affects are. No lesson learned from the plastics. So one of these days they’ll release the wrong material, I think.