> because local effects have proven too inconvenient to voters.
I don't think you need a reminder that their inconvenience is about to get a whole lot worse. When I said they should convince everyone, I meant the voters too. A renewed awareness campaign at this point is not such a bad idea. It's definitely not as costly as the fantasies as these people are proposing.
Compared to this, a planet-wide engineering project might be less absurd and more doable.
Even the EU is under strong internal pressure to water down its decarbonization project, because local effects have proven too inconvenient to voters. Green vote has gone down all across Europe, and that translates to reduced political influence of the ideas you are speaking about.