See also the exercise for restoration of balance at 70 km.
Note the CO2 band at 667 cm-1 is saturated at 300 ppm,
except for the wings of the band. Hence the radiative forcing for changing
from 0 ppm (gray) to 300 ppm would be ΔF=28.32 W m-2; changing
radiative forcing from 300 ppm to 600 ppm is ΔF=3.39 W m-2.
An increase in CO2 from 0 ppm to 300 ppm reduces outward radiation, which by definition is a
positive radiative forcing, with ΔF=28.32 W m-2.
An increase in CO2 from 300 ppm to 600 ppm produces radiative forcing of
ΔF=3.39 W m-2.
A constant temperature increase ΔT=1.02 K in the troposphere (from 0 through 11 km) is able to
restore the outward infrared irradiance F↑ at 20 km to its original value.
frame 4. If relative humidity remains constant (and thus specific humdity rises) as temperature increases,
then ΔT=1.50 K.