The heating alone would do that, yes. It's the knock-on effects. As CO~2~ rises, the ocean slowly acidifies. As the ocean increasingly acidifies, oxygen producing lifeforms (approximately 70% of the oxygen we consume is produced in the ocean) increasingly die out. The Amazon Rainforest (a large producer of oxygen on land) is on fire. What will we breathe? It's an ecological apocolypse, not merely from getting hot (which your comment seriously underestimates the direct effects of) but from the previously mentioned oxygen crash, and hundreds of other effects that we know about and can reliably predict.

edit: some light reading: https://en.wikipedia.org/wiki/Ocean_acidification

DarkNightoftheSoul already helpfully answered that (with link attribution!:-) but I did want to add that I never said that it would - I said that it may, as in in the absolute worst case scenario. By comparison, the ending of a nation, like Ukraine, Russia, the USA, or China, pales by comparison, given how on the other side we are talking something affecting all human habitation on the planet, with the worst case scenario possible being to bring it to an end, though even if that doesn't happen there will be other effects. Like for one, perhaps no more coffee or chocolate, which historically were grown closer rather than farther from those equatorial zones that you mentioned. Even if the thought of billions of deaths doesn't motivate us, at the very least the thought of losing our cafe mocha lattes should!