[update: Tyler Robinson has replied in comments — Tim /update]
Talkshop contributor ‘Cementafriend’ has emailed me with an interesting critique of parts the 2013 Robinson & Catling paper Common 0.1 bar tropopause in thick atmospheres set by pressure-dependent infrared transparency
. He is an engineer and tells me that:
I have had actual experience with combustion and heat transfer. I have designed burners for coal, gas, oil and waste fuel materials. I have measured CO2 in exhaust gases, down coal mines and even in the atmosphere.
The presence of OH in the atmosphere is due to the reaction CH4 +O3 > CH3OH +O2 (of course other organics can also be oxidised by O3 but the quantity of these is tiny).
The reaction claimed CH4 +OH> CH3 +H2O is not correct. CH3OH (methanol or methyl alcohol sometimes known as wood alcohol which is poisonous) can exist as a molecule. In water this can form the ions CH3+ and OH-.
CH3OH is highly soluble in water at ocean/lake surfaces and also in drops of water in clouds. However, there is little O3 in the atmosphere up to 11,000 km and that is why CH4 persists in the atmosphere now at around 1.7 ppm.
It seems that just as there are “Climate Scientists” making up false relations in physics, thermodynamics & heat transfer (luckily they have not touched mass transfer), there also seem to be “astrophysicists” and “astrochemists” making up new chemistry & reaction kinetics.
Another point about the Catling paper is the assumption from a Karl and Trenberth paper of the contribution for clear sky greenhouse radiation of approx 60% from water vapor, 25% from CO2, 8% from ozone and 7% from other gases and aerosols. That ratio does not even occur in a combustion gas with say 12% CO2. In the atmosphere the radiation from 400 ppm CO2 at an average temperature of say 250K is so small it is insignificant and could not be measured. Water vapor in the atmosphere varies over different parts of the globe and is said to average about 2.5%. The range of e-m frequency of radiation for water vapor is at least 10 times that of CO2. So in a clear sky water vapor is by far the dominant (over 90%) radiation emitter from the atmosphere to space.
Two other problems which both have been neglected. Firstly, the radiation window which Trenberth has published as 40W/m2 has been calculated by the late Dr (Chemical Engineer) Noor Van Andel to be 66 W/m2 and it appears that Trenberth in email correspondence confirmed that in writing. (This means there is no need to have backradiation in the calculation of a global energy balance).
The second neglected point is that droplets of water and particles of ice in clouds also radiate to space. Both ice and water have high emissivities over the range of temperatures in the atmosphere (including the frequency range of around 14.8 micron in which CO2 can radiate). In the range of frequency around 14.8 micron satellite measurements can not distinguish how much radiation is from CO2 and how much of it comes from a) the surface or b) from droplets of water & ice particles in clouds.