Comment by Ken Gregory moved from Greenhouse Heat Engine.

Last month I asked Ferenc Miskolczi to calculate a 60 year trend of optical depths using radiosonde data I compiled from the NOAA Earth Systems Research Laboratory to confirm his prediction of constant optical depth. We finally got the results:

*There has been no increase in the effective amount of greenhouse gases in the atmosphere during the last 60 years.*

Miskolczi’s theory shows that the atmosphere maintains a “saturated” greenhouse effect, controlled by water vapor content. The theory predicts the optical depth will remain approximately constant at 1.87. This is a longterm equilibrium value, but will vary over the short term with El Nino/La Nina, etc. Our atmosphere holds just that amount of water vapor that allows the maximum radiation of heat into space. This causes a constant greenhouse effect, so as CO2 increases, water vapour decreases.

This graph shows the global relative humidity trends.

The average relative humidity at the 300 mbar altitude has declined by 21.5% from 1948 to 2007.

The results of Miskolczi’s calculations using his line-by-line HARTCODE program are given here.

The calculations are independent of any greenhouse theory and contains no assumptions on how the greenhouse effect works. The 60 year average optical depth of 1.869 matches the theoretical 1.87.

In 60 years of CO2 emissions, the optical depth trend line has increased about 0.03%, which is nothing, resulting in no temperature change. The result confirms the theory, and shows that the total effective amount of greenhouse gases have not increased in 60 years. Therefore, the warming during the last century was not due to greenhouse gas emissions.

The blue line on the graph shows what the optical depth trend would be if only the CO2 is changed, with water vapour held constant. This is the no-feedback case. The trend line shows 0.3% increase over 60 years. By my calculations, using Eq. 18 and 28, Su increases by 0.131%. The corresponding temperature increase is 0.083 C. During this 60 years, the CO2 content increased 24.6%. So the temperature change at co2 doubling is 0.26 C.

This agrees with the estimate of 0.24 C on page 22.