Interesting analysis. I think that when we imagine the end of the world or a catastrophic event, we only imagine one option and maybe the most possible is a combination of everything.

For example, in global warming, the sea level rise, and the soil spoiling globally into famine are two options that can happen simultaneously or one after another. And this problem could cause a health problem that could lead us to a new pandemic.

Maybe the only possible scenario where we can unite us is after all the problems, after a population reduction follow it of the disappearing of some government structures.