Never mind that it's not practical, it's also simply not moral. Rich people in the west probably could and should use less energy, but something like 3/5ths of the world are entering the global middle class, and it's just wrong that we sit in out Teslas and tell them to forego the comfortable high-energy lifestyles that we've benefitted from.
Statistical morality is not something that humans or even moral philosophers are very good at, but that doesn't mean it can be ignored. Statements like "the probability of a flood exacerbated by sea level rise causing X million people to die in Bangladesh goes up by Y for every liter of gasoline you use". Y is very small but it's not zero. Does that mean that if some disaster happens everyone who uses gasoline is very slightly culpable? It's difficult to talk about.
> forego the comfortable high-energy lifestyles
One interpretation of the IPCC reports might be that "if all 7bn+ people on earth use American levels of energy from fossil fuels then the average temperature will rise by an amount which will cause massive crop failures". That is, it might be impossible as a matter of physics for everyone to have comfortable, cheap high-fossil-energy lifestyles while still growing enough to eat.
It's better than our "solution" of not good enough incremental progress on reduction and not good enough incremental increases in renewable energy. Neither of those baby steps deal with the amount of CO2 already in the atmosphere.
Well, yes, that's the trillion dollar question. How do you get it funded?
Change in behaviour is not what humans are good at. Proof: "Thou shalt not kill".
Just launch the damn solar shade already!