The global regime. So, all of them, to some degree at least. Large tracts of the world will simply become uninhabitable for humans due to rivers drying up, wet bulb temperatures being too high for human survival absent ac, etc

This will push people to kigrate or start wars. And our system won’t be able to handle a much larger amount of migrants, it’s straining even under existing low numbers.

You generally never saw a collapse in just one part of an empire. So I mean a collpase of lur global civilization, on the scale of past collapses that affected prior local civilizations.

We depend on caebon to feed the people we have, too. If we try to reduce and can’t replace, we have trouble. But if we don’t reduce, we have worse trouble as temperatures keep going up.

If we sort out energy and figure out how to suck co2 from the sky we can reverse this of course.