According to the authors,
Using a 3D idealized global circulation model (GCM), we systematically examine the thermodynamic effect of atmospheric mass on near-surface temperature. We find that higher atmospheric mass tends to increase the near-surface temperature mostly due an increase in the heat capacity of the atmosphere, which decreases the net radiative cooling effect in the lower layers of the atmosphere. Additionally, the vertical advection of heat by eddies decreases with increasing atmospheric mass, resulting in further near-surface warming.The authors find,
"The convective fluxes may decrease with increasing surface pressure due to an increase of the moist adiabatic lapse rate and therefore an increase of the near surface temperature [Goldblatt et al 2009]
Increased atmospheric mass, which decreases low-latitude radiative warming and high-latitude cooling, tends to flatten the meridional temperature gradient and this may ... trap heat at the surface."According to the authors, a doubling of surface pressure causes a large surface temperature warming of 15C after all feedbacks.
The authors conclude,
An increase in atmospheric mass causes an increase in near-surface temperatures and a decrease of the equator-pole near-surface temperature gradient. Warming is caused mostly by the increase in atmospheric heat capacity, which decrease the net radiative cooling of the atmosphere.Thus, the gravito-thermal greenhouse effect has been modelled to cause a ~15C surface warming per doubling of atmospheric pressure on Earth. This is compared to a ~3C surface warming per doubled CO2 according to the [faulty] IPCC models.
The ~33C gravito-thermal greenhouse effect on Earth leaves no room for an additional 33C Arrhenius radiative greenhouse effect, thus ruling out any significant greenhouse effect from increased CO2.