A novel “engineering” approach to precision and accuracy in computing the greenhouse gas (GHG) effect on Earth’s temperature
67-page PDF, Rodney McInnis, May 2024
After this podcast was published, Will Happer sent this related email, reproduced here with his permission: “You can't really avoid estimating 0.8 C or something close to it for the feedback-free warming of the Earth caused by instantaneously doubling CO2. The issue is whether there are huge positive feedbacks that multiply this feedback-free warming by factors 4 or more, as claimed by IPCC, or whether the net feedbacks are negative, as they are for most natural systems, in accordance with Le Chatelier's Principle.
Rodney is right about the importance of the adiabatic lapse rates of Venus and Earth. Greenhouse gases and clouds determine the altitude at which the adiabatic lapse stops and heat transfer is dominated by radiation rather than convection. You must have convection, driven by the atmospheric heat engine, to maintain an adiabatic lapse rate. Otherwise, the conductive or radiative transfer of heat from warm to cooler air would drive the atmosphere to an isothermal (maximum entropy) state.
The entropy per kilogram of an adiabatic atmosphere is the same from the surface to the tropopause. But without convection, heat flow upward would increase the entropy per kilogram of higher altitude air, making the atmosphere stable to convection, and eventually making the whole atmosphere isothermal, with much larger total entropy than an adiabatic atmosphere. This sort of hypothesizing probably is more confusing than clarifying, but it is scientifically correct.
Roughly speaking, the heat source of atmospheric engines is the solar heated surface, the waste heat is dumped to space from the tropopause, where thermal emission from greenhouse gases can finally reach cold outer space. The work of the engine drives the winds and other atmospheric motions.”