If ever there was a strawman. He says: "Planes emit CO2 - but they emit almost completely clean CO2 (note that bar global warming, CO2 isn’t considered harmful)

If ever there was a strawman. He says: "Planes emit CO2 - but they emit almost completely clean CO2 (note that bar global warming, CO2 isn’t considered harmful). Volcanoes blast tons and tons of all kinds of nasty and not so nasty stuff into the air. Some of the ash contains nutrients that will fertilize soil, other will, as mentioned, cause acid rain. It’s much more complex than CO2." Well... no, the question raised is clearly about CO2 and nothing but CO2. How much do volcanic ash clouds affect the planet's albedo? How much precious fossil fuel do the planes collectively consume? Not relevant.