I have a question on global warming?

Why is it that no one says anything about volcano's and the sulphur and gases they let off in the atmosphere, causing acid rain and creating a cloud that stays in the atmosphere for over three years and causing havoc beacuse of it. they do not say to much about this and also their nuclear test sites where they blow these things up underground this also causes a chain reaction in the earth creating earth quakes in other parts of the world. And what about airplanes that fly in the atmosphere, do you know that before a plane reaches its leveling off altitude it has dumped 20 to 35 percent of its raw fuel right out of its engines. look for the trail behind the plane.