However, we don't know the best substance to use and we certainly don't know what kind of side effects it would have. Historically, humans have been very bad at predicting bad side effects (e.g. cane toads in Australia) so I am sceptical, especially when businesses will be trying to make profit from it.

It seems to me like the start of a dystopian sci-fi story with humanity retreating from the surface as acidic rain destroys all plant life.

When the alternative is failing crops and hot bulb events - it will happen eventually. We did this for over 100 years btw., just as a by-product of burning fossil fuels. Cleaner technologies and air pollution regulations have unmasked real global warming scale in northern hemisphere.