The impression is gained that there is still no conclusive physical description of the global behavior of CO2 absorption/emission in the various reservoirs. There is a growing group that is convinced, the residence time of CO2 in the atmosphere is approximately 4 years. Another group assumes a significantly longer residence time of 30 years or more. Finding a common consensus between both sides appears difficult.
An attempt is made here to provide an approach. It can be viewed as a complement to other articles recently published in Science of Climate Change. We assume that there is a regular exchange of CO2 between the reservoirs, both in terms of absorption and emission. Without anthropogenic emissions, absorption and emission balance each other.
The approach assumes an equilibrium of CO2 concentrations between the various reservoirs. Any additional amount of CO2 introduced into the system is distributed in a constant ratio among the reservoirs.