Reply To: Questions regarding DPF.

[Brian H]

mchargue wrote: I read the entire paper. From the conclusions comes,
—–
From what we understand about the underlying
processes, uptake of atmospheric CO2 should react not to a
change in emissions, but to a change in concentrations. A
further analysis of the likely contributing processes is necessary
in order to establish the reasons for a near-constant AF
since the start of industrialization. The hypothesis of a recent
or secular trend in the AF cannot be supported on the basis of
the available data and its accuracy.
—–

It seems clear that the author is talking about the a atmospheric fraction (AF) that is ‘nearly constant’ since the start of industrialization. All the talk about increases seems to be speaking to the increase in the amount of CO2 industrialization injects into the atmosphere, and to the amount of natural sequestration that’s taking place.

The take-away point seems to be that the concentration of CO2 in the atmosphere is nearly constant, and has been for some 150 years.

Pat

Indeed. The 45% which persists beyond one cycle is a result of mixing, which is counter-balance by “other” CO2 which is sequestered by the same bio-geological processes which have turned most of the planet’s supply into limestones, etc., over the past few hundred million years.
If anything, the density and mass of the atmosphere have dropped considerably over that time span, possibly by a factor of 2 or more, over that time, so the total mass of CO2 has probably gone down substantially.