By Norm Kalmanovitch
Time to get back to basics and proper scientific definitions. In matters of global temperature change first we should address the Geophysics and then Climatology in that order!
Geophysics is the scientific discipline under which the processes that control global temperature fall. Climatology is the scientific discipline under which the study of global temperature changes falls.
I am a geophysicist so I get the first word on what, and especially what doesn’t control global temperature changes.
Outgoing longwave radiation (OLR) has been measured by satellites since 1979 increasing from 231W/m2 in 1980 to 233W/m2 today with an average of roughly 232W/m2 over the past 38 years.
Energy balance requires that net incoming energy equals outgoing energy which means that total solar irradiance (TSI) minus albedo must be equal to outgoing longwave radiation.
TSI as measured on the old scale is 1366W/m2 but since this is incident energy and therefore relative to the cross sectional area of the Earth (πr2)
OLR is measured relative to the entire earth surface (4πr2) so to equate these we need to divide TSI by 4.
This gives us a value of 341.5W/m2 for TSI equated to OLR
Since net incoming energy must equal outgoing energy we get the equality of
341.5W/m2 minus albedo equals 232W/m2 requiring an albedo value of 109.5W/m2 or 32.06%.
If there was no atmospheric insulation slowing down the rate of cooling according to the Stefan Boltzmann law the earth’s surface would be heated to the temperature of 252.91 K which would radiate the 232W/m2 into space as observed with OLR measurements.
The actual average surface temperature as determined by the proxy of near surface air temperature is 14.15°C or 287.30 K.
The reason that this 287.30 surface temperature is 34.39°C warmer than the calculated effective radiating temperature of 252.91 K is that atmospheric insulation slowed down the rate of cooling, forcing a higher and higher surface temperature that would overcome the atmospheric insulation enough to allow OLR of 232W/m2.
This insulation is provided mostly by the roughly 50% variable cloud cover present at any given time and by water vapour in the atmosphere.
The insulation is also provided by CO2 in the atmosphere which is responsible for about 10% of the insulating effect. Once CO2 in the atmosphere reaches the 300ppmv concentration level there is virtually no further insulating effect and since the atmosphere is now above the 400ppmv CO2 concentration level, there is no detectable change in atmospheric insulation from CO2 which remains at the same roughly 10% of the total atmospheric insulating effect; regardless of how great the increase in CO2 concentration.
What can be taken from this simple explanation is that CO2 in the atmosphere contributes to insulation and insulation slows down the rate of cooling (or warming) and therefore does not cause warming (or cooling)!
At the current CO2 concentration level of over 400ppmv further increases in CO2 concentration (regardless of source) have virtually no additional insulating effect and therefore have no further effect on slowing down the rate of cooling!
Us geophysicists are rather simple folk and need to bring things down to basics and ‘first principles’ such as energy balance and the Stefan Boltzmann Law without having to bring in complications such as whether the Earth radiates like a blackbody or if we need to correct the Stefan Boltzmann constant “σ” for emissivity.
By simply staying true to first principles, we can easily prove the ludicrous conjecture of CO2 emissions causing dangerous global warming to be completely false.
Our only failure is calling this surface temperature minus effective radiating temperature geophysical metric for atmospheric insulation “the greenhouse effect” which appears to have confused everyone into believing that this is an effect when it is merely the subtraction of a theoretical temperature value from a measured surface temperature value!