robock points out that it's necessary to have some kind of fuel, but i think that blowing up mountains is certainly going to throw more dust into the air than blowing up a beach. further, i've seen reports that some of the bombs they were using in afghanistan and iraq were (while conventional) considerably more powerful than the smaller sized nuclear weapons.
somebody ought to see if they can draw a connection between the bombing that happened after 9/11 and the decrease in warming that followed.