Apparently volcanoes make CO2 when convenient. Most of the time the claim is that volcanoes produce much less CO2 than humans. But when convenient for the global warming argument, the claim is that volcanoes produce huge amounts of CO2.
BTW – over 100,000 years, vegetation and the oceans produce 20 million gigatons of CO2. That is 4,000 times more than what the author is claiming for the volcanoes. He must have placed very accurate sensors around the planet back during the Paleocene to be able to measure to such precision.