This is a problem primarily because there are nearly 8 billion people plus national borders. If we were still all "primitive" and sparsely populated nomadic hun

This is a problem primarily because there are nearly 8 billion people plus national borders. If we were still all "primitive" and sparsely populated nomadic hunter-gatherers, people would just migrate away from these areas and go to more temperate areas that global warming is essentially thawing. But we can't readily do that because that would mean emptying out specific nations and exporting their people to other nations and that ends up being hugely problematic. If it were only climate change, this would be kind of meh. But it's not, so it's not.