Those predictions were based upon projections that we would not address the growing levels of smog and other particulates, and the cooling effect from those would be larger than the warming effect from greenhouse gases.
We did address smog. Without growing smog, those models predicted warming.
Would increasing particulates be an effective way to stop global warming?
That's one proposal for geoengineering (either sulfate particles in the stratosphere, or marine particles over the oceans). More for a "pause" or slow down rather than a solution to stop it.
Definitely, there was an "albedo yachts" solution that was floated a while back. Basically kicking up mist from the oceans. It's all just theory, and the repercussions are probably not well understood, but the idea is out there and implementation would be relatively inexpensive.