[quantim]

For example, see this:

How Much CO2 Does A Single Volcano Emit?

Exceprt:

We can measure the degassing of Mt. Etna extremely well, and find that it adds about 16,000 tons of CO2 to the atmosphere each day, or 5.8 million tons per year. This might not sound impressive, but it's only one volcano. Interestingly, it's not just smoking, actively erupting volcanoes that emit CO2, but seemingly inactive volcanoes around arcs and rift zones. Persistent degassing still occurs around a great number of volcanoes worldwide, on a continuous basis.

*
Add all of these up, and you get an estimate of around 645 million tons of CO2 per year.

[oldtech]

Are you saying this CO2 is the problem? It isn’t, but the other gases & things that emit from a volcano certainly could be. If a volcano emitted only CO2, I doubt we would even notice the difference. The green plants would, but what harm would there be from a volcano like that?