[UPDATE: readers should be aware of a correction on the source site. The best estimate of CO2 is in fact 150,000 tons per day, not 7400, with a possible maximum of 300,000 tons per day. So the graphic is much less compelling, but the story of Joe vs the Volcano is not affected.]
Even if I can’t say it, the volcano Eyjafjallajokull is great to illustrate just how ludicrous the “Volcanoes emit more CO2” argument is. Courtesy of Information Is Beautiful, here is a very telling graphic.

Is there really a need to say more?