Climate sensitivity as the effect on the Earth surface temperature of doubled atmospheric CO2, is by IPCC estimated to an alarming + 3 C. The idea is that CO2 by acting like a "greenhouse gas" blocks radiation from the Earth and thus causes warming. This is a very primitive idea and as such it may well be wrong.
- The Earth surface is heated by incoming energy from the Sun, and the Earth-atmosphere system radiates an equal amount of energy from an outer boundary or top of the atmosphere TOA at the tropopause at a pressure of 0.2 - 0.3 bar.
- The surface temperature is determined by the lapse rate from the temperature at TOA.
- In an atmosphere without thermodynamics of advection (still air) energy would be transported from the Earth surface to TOA by a combined process of conduction and radiation, which would require a linear temperature profile with constant lapse rate equal to the dry adiabatic lapse rate of 10 C/km as the maximal rate of a stable atmosphere without advective overturning (thus establishing the Loschmidt gravito-thermal effect).
- The observed lapse rate in the real atmosphere with thermodynamics of advection is 6.5 C/km.
- Increasing thermodynamics would thus tend to decrease the lapse rate and with a temperature of TOA unchanged, would thus cause global cooling.
- The logic is that more vigorous thermodynamics would transport energy more efficiently from the Earth surface and thus cause cooling.
The rationale is that conduction/radiation passively operates on a temperature gradient/lapse rate maintained by exterior forcing, while thermodynamics/advection actively works to decrease the gradient/lapse rate. To see the active part dominate the passive would not be surprising.