Let me sum up the two previous posts to make the argument clear. The crucial observations come from an infrared satellite thermometer in radiative contact with the Earth + atmosphere, which selectively can measure the temperature of different frequencies. Reading of the infrared thermometer shows the following temperatures:
- 220 K for wave numbers 600 - 800 (attributed to the trace gas CO2 at the tropopause)
- 288 K for wave numbers 800 - 1200 (attributed to the Earth surface)
- 255 K for wave numbers below 600 (attributed to water vapor at 5km altitude).
- R(n) ~ T n^2
In other words, even with a vanishingly small presence of CO2 in the atmosphere, a sufficiently sensitive thermometer would be able to report a temperature of 220 K in the range 600 - 800, as the evidence of a powerful GHE.
Evidently the Nimbus 4 thermometer was sensitive enough to report in 1970 the temperature of the atmospheric trace gas CO2 (390 ppm = 0.039%) to be 220 K in the troposphere.
This opened to the CO2 global warming alarm based on the argument that even if CO2 is a trace gas, it has the power of changing the climate of the Earth, with the evidence being the visible ditch in the radiance spectrum documented by the reading of the Nimbus 4 thermometer.
But the ditch in the radiance spectrum is constructed from a selective reading of the temperature of CO2 and may not represent reality, only the reading of a vanishingly small effect by a very sensitive thermometer.
The discovery of the GHE is thus directly connected to the use of the sensitive Nimbus 4 thermometer:
- The major effect of atmospheric CO2 is evidenced by a very sensitive instrument, as if an elephant is discovered by a microscope!