Aeronautical Engineer challenges IPPC Climate Change CO2 theory/narrative

The following interesting informal paper was kindly sent to me by an aeronautical engineer who decided to investigate the controversy over the Co2 theory. He investigated a treatease by Gordon Vigurs on the subject written by an engineer who’s spent a lifetime working with heat transfer problems and modelling gas-turbine (“jet”) engines for control systems. It’s an informal paper, not published, but he claims it is the most rigorous analysis he has ever seen and only deals with the greenhouse theory from first principles.
You can download the PDF here:
It’s hosted at this page: https://gvigurs.wordpress.com/2019/04/
The concepts directly address the greenhouse theory. He claims page 14  is the key to understanding why the subject has become so contorted and misunderstood stating
“Note the term “epsilon”. That is the emissivity of the gas (what makes it a “greenhouse gas”). It allows the gas to absorb heat at a slightly faster rate, however (and this is the key point), it doesn’t change the amount of heat the gas can absorb. That is determined by other characteristics (such as the density) and the amount of heat being radiated into it. Once the gas reaches an equilibrium temperature, it radiates out as much as it absorbs.
However, there is a second subtlety that is important: It radiates heat back down – as per ‘greenhouse effect’ Wikipedia. However AT THE EQUILIBRIUM TEMPERATURE (<—that is the important bit) the downward flux and upward flux are equal and opposite. There’s no additional accumulation of heat because no heat transfer. (A bit like two people at either end of a rod, pushing on it towards each other. The forces are in balance and opposed so the rod doesn’t move). So any additional heat gets radiated to the upper layers.”
He claims it does demonstrate how the greenhouse gases simply don’t trap any heat beyond what their regular heat capacities (determined by pressure and density) allow them to.
Here is his general commentary on the Co2 theory: https://gvigurs.wordpress.com/2019/07/10/on-duff-science/