These kinds of solutions scare me because of their short-sightedness. I haven't seen any comforting explanations of how these reflective particles leave the atmosphere and where they end up such that their effects can be stopped. Solar energy has been and will continue to be the only actual source of energy on our planet. All other resources are finite and will eventually be depleted, many within our lifetimes or those of our children if reserve estimates are accurate. If our strategy for using finite energy resources is to block out the energy from our only infinite (at least millions of years worth) energy source, it would seem that we are shooting our grand children in order to have a bigger party today. Once the prices of oil and fissile materials get high enough, we'll be facepalming at a global scale when we have to rely on solar-derived power (biomass,PV,wind,etc) to fill the gap. Even if there are no unintended consequences (which I do NOT believe is the case), the intended consequence of reducing the total solar energy input to the planet seems like a simple case of short-term fix, long term problem.