The obvious one is simulating a volcanic eruption such as Mt. Pinatubo. There is also whiting of clouds with sea spray. There are probably others that I'm not aware off. There are big questions around the side effects of such technology. Main one, even if all goes well, we are left with the acidification of the oceans, and the resulting effects on all kinds of vulnerable larva as they try to form skeletal structures, be it eternal or external. The bottom line is some country will end up being a loser, as all that extra moister comes back down to earth. I've thought about it, and your right that companies will probably escape libel even if it can be proved, but that might not stop retaliation from a country at the end of it's rope.