Not sure how you came to the 1st conclusion. On the 2nd, yes volcanos spew rock and ash into the atmosphere. Engines dont run well on ash or rock. This has nothing to do with relative CO2 emissions of volcanos and the human population.Your above post indicates that respected scientists don't have a clue? However if you choose to believe that is a myth that is your choice, however I wonder why aeroplanes needs to avoid areas around volcanoes if there is no pollution and that their engines will not be destroyed if the enter a cloud of volcanic ash?