Well, the geologists have a principle that states what processes are working today likely caused the features of the past. You know, the Mississippi deposits silt, and this gets made into rock...
So if we know something caused temperatures to drop in the past, the same thing would happen if we put that process in effect today.
Volcanic ash from erruptions in the 1800's caused a big temp drop.
How many planes fly a day??? Repulverise the ash, dump some of it out in high altitude and use the soot to reflect off the sun... Stop when you notice an effect. If we increase the reflection, more CO2 means faster growing plants until they balance things out
I'm sure they'll figure out something when the water starts rising
Mike Horne