Even if we solve the political and technical aspects of the problem, most of the Earth's habitable history has been at mich higher mean temperatures. Either finding ways to adapt to that, or modify it should definitely be on our todo list. Just because we don't slam ourselves directly into planet-sterilizing feedback loop, doesn't mean we aren't going to hit elevated temperatures in the future. We maybe only have half a billion years until increased irradiance kills everything, so having a parasol before then would be nice. Could get the planet another couple billion years of habitability.