Earlier quoted context omitted.
This is not correct. Please go through each one again, taking special note of global warming and nuclear weapon development .
Humans are voluntarily driving themselves to extinction through sub-replacement birth rates worldwide. That's going to play out far quicker than global warming or pretty much anything other than every country on earth launching nukes at each other will.
Africa is still growing massively for example, world is not just western civilization. Sure at that rate and incerase of living conditions for everybody maybe in 1000 years population will be smaller, but its not that hard to fix if wanted - people used to have 10-15 kids as default.