At this point I'd suggest big investments in research into geoengineering. For example, I can find research stating that aerosols will work, BUT that will have

At this point I'd suggest big investments in research into geoengineering. For example, I can find research stating that aerosols will work, BUT that will have costs. But which costs? I can only find a few studies about the truly stupid ideas (spreading sulphuric acid in the stratosphere will cool the earth ... then rain down. Yes I can understand why that would be bad. But any aerosol will work, of course. What goes wrong when spreading Lithium? Phosphate? Natrium? Magnesium?)