Geoengineering to cool the Earth might be doable for 2 billion dollars per year. It would delay global heating disaster, perhaps long enough to take other permanent measures.

It would not stop ocean acidification, which threatens to wipe out all coral and molluscs and make some species act in crazy, dangerous ways.

It would also not stop the increased CO₂ from making many food plants produce less protein.

All in all, it would be better to push renewables and electric storage.