How much green house gases come out of one volcanic eruption?

Answer 1

This is a how long is a bit of string question!

Eruptions vary from small and over in minutes to huge cataclysmic explosions or ones that carry on for years.

What has been shown recently is that a volcanic eruption actually depleted the ozone layer in it's plume. Whilst the effect was small and quickly repaired itself it has given scientists something new to look at.

Answer 2

does it make any difference as long as the plants can take care of converting the CO2 to oxygen. I have been unable to detect any increase in CO2 .