Putting sulfur into the right layers of the atmosphere seems to be the currently best viable options. It's not overly expensive, either. It acts fast and is reversible.

https://en.wikipedia.org/wiki/Stratospheric_aerosol_injectio...

Dumb question: would this also lower solar panel yields?

Thank you. This reading lowers my anxiety. I believe we'll rationally - and in a hurry - come down to this kind of solution. It makes solid sense.