How much carbon dioxide is in a volcano?

Question: How much carbon dioxide is in a volcano?
- Keywords:
  carbon dioxide,
  gas,
  volcano
Asked by anon-192790 on 14 Nov 2018.
- anon answered on 14 Nov 2018:
  
  A huge amount. The Internet says about 0.3 billion tonnes a year (about 1% of human CO2 emissions). A really big eruption should release even more CO2 but it depends on the chemistry of the rocks.

Question: How much carbon dioxide is in a volcano?