While many of the points made by Harde (2023)  are right, a few points are not right and need correction. That includes allegations of certain statements of the IPCC they never did or intended in the way that Harde interpretated.
I was preparing a large comment on the paper by Harde and Salby (2022) , but the comment by Andrews (2023)  was published before mine was finished. Most points I was preparing were already given by Andrews, so I don’t need to repeat them here.
Even if Andrews did mention several items in a simple way, that doesn’t mean that these remarks are wrong, neither is a more technical explanation right if the reasoning behind it is wrong…
The mass balance.
Whatever the CO2 sources and sinks in the atmosphere, the carbon mass balance must be closed at any moment of time. No carbon can created from nothing, no carbon destroyed. Except… 14C which is created by cosmic rays and destroys itself by radioactive decay. Because that are extremely small quantities, that doesn’t influence the mass balance of the bulk CO2 amounts.
Let us have a look at the mass balance over the past 60+ years since the exact CO2 measurements at Mauna Loa started, together with the South Pole:
Continue reading: Understanding Increasing Atmospheric CO2 by Hermann Harde.