Guest Post by Peter Morcombe
Verity Jones kindly provided a soap box for me to compare the theories of Nikolov & Zeller to those of “Climate Scientists” exemplified by Scott Denning. If N&Z are right the huge sums of money governments around the world are committing to “Mitigating” CO2 emissions can have no effect on global temperature.
In the discussion that followed supporters of Scott Denning were asked to provide an equation expressing the relationship between atmospheric CO2 and global temperature. David Appell was bold enough to take the challenge by citing Arrhenius’ 1896 paper. Arrhenius makes the counter intuitive assertion that minor components of the atmosphere such as water vapor and CO2 overwhelm the effect of the bulk of our atmosphere:
“The selective absorption of the atmosphere is……………..not exerted by the chief mass of the air, but in a high degree by aqueous vapor and carbonic acid, which are present in the air in small quantities.”
Arrhenius goes on to develop a relationship between CO2 concentration and global temperature as summarized in his “Table VII” predicting the variation of temperature (oC) as a function of CO2 concentration:
The Arrhenius figures are in italics. A weighted average has been calculated that follows the function shown above. “A” in the above table represents the concentration of CO2 as a ratio to 280 ppm (the approximate CO2 concentration in 1896). The Arrhenius theory is elegant in its simplicity and it is still the theoretical basis for the “Catastrophic Anthropogenic Global Warming” theory. Let’s take a closer look at what it implies.
With the benefit of hindsight we can test Arrhenius’ predictions against the observed warming from 1896 to the present. According to NCDC the average global temperature increased 0.7 K compared with ΔT = 5.43 log(2) (395/280) = 2.7 K. The Arrhenius prediction is not even close but there are other problems.
The trouble with “Halving”
The Arrhenius theory can be used to predict the effect of high or low CO2 concentrations. Arrhenius’ specific predictions are shown in blue while halvings are shown in yellow. In 1896, Earth’s atmosphere contained ~2,200 Giga-tonnes of CO2, so 20 halvings would reduce this to about 2 million tonnes which means it would take another 115 halvings to get down to just one CO2 molecule.
At that point the temperature would be over 400 Kelvin below absolute zero. As this is a physical impossibility the Arrhenius theory fails this sanity test. While one can excuse Arrhenius for overlooking this, modern “Climate Scientists” should have either abandoned the Arrhenius’ theory or modified it to address this issue.
The trouble with “Doubling”
According to James Hansen, adding CO2 to the atmosphere will cause a “Runaway Greenhouse Effect”. After 18.3 “Doublings” the partial pressure of CO2 on Earth would be identical to the surface pressure on Venus. In Fig. 1, the corresponding “Delta T” is 99 K above the 1896 value of 287 K = 386 K. While this sounds pretty scary, it is far short of the observed surface temperature on Venus which is ~350 K higher. A spectacular “Fail” for James Hansen.
The temperature increase predicted by the Arrhenius theory can be expressed as a “Forcing” in Watts per square meter. While the sun delivers about 1,367 W/m2 only half of the planet is illuminated at any given moment and over 30% of the incoming radiation is reflected. The average power absorbed is ~345 W/m2.
After ten doublings the partial pressure of CO2 would be 0.29 bars and the forcing would be ~345 W/m2, equal to the solar radiation absorbed at Earth’s surface. This would imply that all the outgoing “Thermal Infra-Red” had been captured by the CO2 and returned to the surface. This is not physically possible so it seems that the doubling effect also fails another sanity test. Once again one can excuse Arrhenius but not modern “Climate Scientists”. In fact the maximum amount of outgoing radiation that can be captured by CO2 and returned to the surface is ~15 Watts/m2 as explained in the “Unified Theory of Climate Revisited”.
Thanks to satellites and modern instrumentation climate scientists such as Scott Denning have access to more accurate data than was available in 1896. Consequently, the modern estimate of the effect of a “Doubling” is ~1.2 Kelvin instead of the 5.4 K assumed by Arrhenius. See Fig. 3.
As mentioned earlier the global average temperature has risen by ~0.7 K since 1896. Back then there was ~280 ppm of CO2 in the atmosphere compared to 395 ppm today. Using the formula ΔT = 1.2 log(2) (395/280) the warming should be 0.6 K, in reasonable agreement with observations. So far so good for Denning but things got worse for Hansen’s “Runaway Greenhouse Effect”. After 18.3 doublings (to 93 Atm.) the predicted warming is only 22 K for a temperature of 309 K. For comparison the N&Z pressure based theory predicts a surface temperature of 628 K on Earth at the same pressure compared with 739 K on Venus.
Here is another “Sanity Check” for the Denning theory. The Vostok ice cores show wide temperature excursions as the planet experienced a series of glaciations over the last 700,000 years. Currently, Earth is enjoying an “Inter-Glacial” with temperatures about 10 K higher than at the peak of the last glaciation. Twenty thousand years ago the temperature was 10 K lower than today. Arrhenius wanted to explain “Ice Ages” in terms of CO2:
“….one might in this way probably find an explanation for temperature variations of 5o-10o C.”
If there was any validity to Fig. 3 the CO2 concentration would have been 8 halvings lower than today or 1 part per million. The Vostok ice cores show that the CO2 concentration never fell below 190 ppm. This failure is beyond spectacular.
No matter whether one takes the Arrhenius idea in its original or updated form it does not come close to explaining observations on Earth or Venus. The theory fails a string of sanity checks and yet scientists around the world act as if it had some validity.
It is puzzling that theories based on thermodynamics explain observations with good precision yet they receive little attention. In 1969 Carl Sagan’s correctly predicted the surface temperature of Venus by applying the concept of “Adiabatic Lapse Rate” from the cloud tops down to the surface. More recently N&Z’s 2011 “Unified Theory of Climate” has accurately predicted surface temperatures on many planets and moons.
My conclusion is that it does not matter what the science says when politics and money dominate.