Were the aerosols from above-ground nuclear bomb detonations? I remember seeing a graph years and years ago that showed the temperatures really starting to rise was above-ground nuclear bomb testing was banned.
Crazy spur-of-the-moment idea - should we pursue dumping some sort of aerosol into the upper atmosphere to reduce the amount of heat Earth receives from the sun? Obviously this shouldn't be pursued in lieu of curtailing our pumping C02 into the atmosphere, but it could alleviate some of the damaging effects from what we've already done.