That would be bad for human health in coastal zones (i.e. most of the population). Better would be to release sulphur in a controlled way so that the effects are far from civilization, like on the middle of the ocean, and then study the relationship with temperature.
That just slight shifts where we are on the warming curve. It doesn't change the growth rate unless we also start rapidly growing the number of transoceanic vessels.
I suppose we have a fallback if things get really bad. It would be better not to rely on that though.