Our Asian brother's have a dedicated Weather Modification Department that boast of being "the largest artificial weather program in the world" including 30 provinces 32,000 people, 7,100 anti-aircraft guns, 4,991 special rocket launchers and 30-odd aircraft across the country. (And a knife with a very sharp blade.) Isreal and Russia are next inline with their more modestly sized programs. Read more here
Could such a program be used on a barren planet like Mars perhaps? What are the implications of changing the climate of an entire planet?