Why would that be a probable outcome ? Why couldn't we just add a little bit of the aerosols, measure the effect, and slowly add some more ?
There is pretty good historical evidence of what did happen when a big volcano blew out lots of ash and particles. Mount Tambora for example, that had an eruption in 1815, and the following year, 1816, became known as "the year without a summer", because of this. There is no good reason to expect a significantly different outcome from filling the atmosphere with other similar particles. It will become colder.
On the other hand, this does argue for the possibility that the system can behave somewhat predictable, with negative feedback as it were, within a smaller range of excitations, like varying the speed of an aircraft as long as it runs faster than stall speed. But once driven past some inflection-point that we can expect to be there, given that the system is chaotic, all bets will be off.
Still, this suggested solution seems to be worse than the problem. The possible increased temperatures and CO2 will just make for better growth conditions for all kinds of plants, of which many are food for animals which in turn are eaten by humans. Less sunlight, less heat, less CO2 and there will be less foliage, then eventually less food available. How can that good for anything?
And finally, back in the 1970s and 1980s, there was a lot of argumentation about acid rain, caused by partculate pollution from coal-fired plants, where the sulfur was precipitated as acid. Countries have managed to put a stop to this kind of pollution, though there are still localized problems with particulate pollution in cities. And now there are someone arguing that this sort of thing actually could be worthwhile in an attempt to halt a perceived warming process?