The longstanding claim is CO2 (greenhouse gas) top-of-atmosphere (TOA) forcing drives climate change. But it is too cold at the TOA for CO2 (or any greenhouse gas) to exist.
Image Sources: Schneider et al., 2020, NASA, UCAR, CGA
TOA greenhouse gas forcing is a fundamental tenet of the CO2-drives-climate-change belief system. And yet the “global-mean longwave radiative forcing of CO2 at TOA” (Schneider et al., 2020) may not even exist.
It is easily recognized that water vapor (greenhouse gas) forcing cannot occur above a certain temperature threshold because water freezes out the farther away from the surface’s warmth H2O goes.
CO2 is in its solid (dry ice) form at -78°C and below.
Therefore, TOA CO2 radiative forcing cannot exist if CO2 cannot be a greenhouse gas at the TOA.