Analysis of CO2 residence times [atmospheric lifespan] suggests that 65% to 96.5% of the CO2 concentration increase since 1958 is natural.
According to a new study, the claim that increases in atmospheric CO2 are driven exclusively by humans relies on a made-up, disparate accounting model, with the residence time for natural emissions three to four years (which is consistent with actual observations), but CO2 from human sources is claimed to have a residence time of 50 to over 100 years. [emphasis, links added]
The 15 to 30 times longer residence time for human emissions is an imaginary conceptualization that is wholly inconsistent with (1) bomb tests (1963) and (2) seasonal CO2 variations found in real-world observations.
Human emissions account for under 5% of the total from all sources, natural and anthropogenic [man-made].