Rodri, this isn't about global warming this is about manipulating weather. Global warming is a different issue and false science. Yes chopping down massive sections of a rainforest can change things on a large scale. However the earth undergoes cycles of weather, some every 7yrs, some every 30yrs, we are finding that some cycles come around every couple of hundred yrs. There are many scientists that disagree on global warming, even the ones that do agree on global warming phenomena do not agree on the particulars. There are two scientists that study the sun, sun spots and solar flares (don't remember what the field of science is called). That have tried to warn that we are due for another minor ice age. the last minor ice age lasted 200yrs if I remember correctly and brought cold summers and longer winters. I don't know about the rest of you but this summer the temperatures where I live were cold, we usually have warm summers with at least 3 weeks of hot weather. This year we had 1 week of hot weather and the rest of the time it was cold and wet, the temp at night would drop down into the 40's. For summer nighttime temps to be in the 40's I find the whole global warming issue to be on shaky ground. Although Rodri that was a very good post and I do believe our actions impact the climate, to what degree no one can say with 100% certainty.

Back to the topic, weather manipulation is possible. Seeding clouds is something that has been fooled with for at least 50 yrs. The problem I see with seeding clouds is this:

Say area A gets 48 inches of rain a year, area B gets 52 inches, area C gets 10.

You increase the precipitation in area B by 20%, by the time the weather system gets to area C that 10 inches of rain a year has now turned into 8. Continually seeding clouds in area B will drop it even further creating no rainfall in area C after some time. This could also create a backup of pressure in area A and create torrential rainfall there and start to cut off the annual rainfall to area B, making seeding clouds in area B a necessity down the road. Soon area B will have a lower amount of rainfall per year as the weather system has now shifted to compensate.