Volcanoes are part of the natural CO2 cycle, which is in balance. So adding volcanoes would be like adding the CO2 animals, including humans, exhale. The proble

Volcanoes are part of the natural CO2 cycle, which is in balance. So adding volcanoes would be like adding the CO2 animals, including humans, exhale. The problem is that we are adding more CO2 to the cycle, disturbing the balance. Since it only was a semi-serious question I'll assume you knew this, but I still think the balance is a good argument to have when you run into deniers.