Question about Global Warming

Why is it that Al Gore and his disciples are not advocating the use of sulfate aerosols to mitigate the alleged effect of global warming?
Please see here, for example.

Sulfate aerosols come from coal burning and copper smelting. Their effect when released into the atmosphere is to increase the amount of radiant hear reflected back into space by the Earth’s atmosphere. 

If this were an engineering problem, it would have an engineering solution. Why is it that the matter is not being discussed in engineering terms?