You are behind the curve, modern thinking is that old oil from the ground is new CO2 and bad, but new oil from current crops doesn't have to be counted because it is from the CO2 presently in the air and emissions are a net zero.
I guess the actual measurements will have to be adjusted for this if they don't show a true reduction over time.
True, oil from the ground contains CO2 long ago 'sequestered.' What is the difference between that 'old' CO2 becoming new plant life vs having 'new' CO2 becoming new plant life? I agree that in the former case there is an aggregate increase in surface CO2 (as opposed to the Carbon being sequestered in the earth) compared with the latter case where the surface CO2 is constant. My question is, that if in the latter case the burning of current plant life will result in future plant life (surface sequestering of carbon) why is it such a stretch to not presume that the former case (where 'old' carbon is pulled out of the ground) will not follow the same carbon cycle and result in more plant life (surface sequestering)? If the 'Carbon' we pull out of the ground is 0.3% of the whole natural carbon cycle, we will have 0.3% more plant life. Much of this additional plant life will return the the soil. Is it really relevant that it is not deeper in the ground?