I have heard about this "acid rain" before, but somehow I was under the belief it was caused by the depleting ozone layer, and contamination from radiation from the sun.
I don't know how many differing theories are out there, but I would be interested in knowing about them.
Have a read of this from info-wars.
Secret "Geo-Engineering" Projects Threaten Unknown Environmental Dan
Posted by: "Paul Joseph Watson" firstname.lastname@example.org onedeaddj
Fri Sep 5, 2008 4:46 am (PDT)
Secret "Geo-Engineering" Projects Threaten Unknown Environmental Dangers
U.S. government scientists bombarding skies with acid-rain causing pollutant in name of fighting global warming
Paul Joseph Watson
Friday, September 5, 2008
U.S. government scientists are bombarding the skies with the acid-rain causing pollutant sulphur dioxide in an attempt to fight global warming by "geo-engineering" the planet, despite the fact that injecting aerosols into the upper atmosphere carries with it a host of both known and unknown dangers.