I actually did some research, and delivered a course in Environmental Legislation for three semesters at Moscow Industrial University. There are huge margins in estimations of both consumption and production of CO2. We lack actual data from one side and we have too many stakeholders with vested interest in "raising awareness about climate change", and selling more "cleaner" cars to take this subject seriously. Ever asked yourself how much of the CO2 footprint the "green" car have? Its way larger than Ford T.
But you'll note, again, that the data I referred to isn't about what cars do or do not emit specifically. It is about whether volcanic eruptions track with significant increases in CO2 in the atmosphere.
Notice how all but one of the individual annual volcanogenic carbon outputs, estimated above, dwarf the global subaerial volcanogenic carbon outputs estimated by both Gerlach (1991) & Kerrick (2001).
If CO2 levels are rising overall, and you claim volcanic eruptions utterly dwarf man made emissions, then years with volcanic eruptions should show an increase in atmospheric CO2 outside of the trend, and years without them should be flatter.
This is not shown in any of data.
But now you claim plants and algae are consuming all the volcanic CO2. So where is the overall increase coming from then? And I'd they are doing this, why, in non-eruption years, does CO2 not fall greatly due to all this biomass?