FALLS CHURCH,VIRGINA, March 30, 2017 – When John Tyndall demonstrated in 1861 that carbon dioxide, and other gases, had the ability to absorb thermal radiation, he theorized that atmospheric changes in the quantity of these gases could cause climate change. Thus began the debate as to how much would the temperature rise if C02 quantities were to double?
An early attempt to calculate this was done by Svante Arrhenius in “On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground“, 1896 and without going into the physics and math, his prediction was that a doubling of carbon dioxide would increase Earths temperatures by 5-6 degrees Celsius on average.
Tyndall, Arrhenius and other leading scientists of their time were studying gases and earth’s temperature in hopes of being able to explain the glaciation periods and broadly, the ice ages.
Scientist wanted to explain how 20,000 years ago, Northern Europe was buried in layers of ice and how it all melted away. Their theory was that greenhouse gases were, in some way, causing these glaciation periods.
It would take until the 1970’s, through the study of ice core and sea sediment samples, that Serbian astrophysicist and mathematician, Milutin Milankovitch’s theory known as Milankovitch cycles would be validated as the cause of glaciation occurring every 100,000 years.
He resolved to develop a mathematical theory of climate based on the seasonal changes Earth goes through in relationship to the Sun causing variations in solar radiation hitting Earth.
An Ice shelf two miles thick over present day New York City whose tailings formed what is Long Island is the result of the last glacial period that ended some 20,000 years ago.
By 1900, Knut Angstrom had the results of his experiments showing carbon dioxide to be less effective in trapping heat because the absorption band of carbon dioxide overlapped with that of water vapor.
Also, it was noted that the amount of carbon dioxide currently in the atmosphere at the time saturated the absorption band, thus, any additional carbon dioxide would have little effect.
This is where the issue stood until in 1938 when Guy Stewart Challendar reignited the debate by presenting his calculations supporting Tyndall and Arrhenius and their conclusions that carbon dioxide had a strong heating effect.
Also, in 1932 Martin and Baker discovered that carbon dioxide existing in many different absorption bands meaning it was not fully saturated as Kurt Angstrom had postulated, making it possible to trap more heat.
In 1950, Strong and Plass observed that heat that escaped the absorption band for carbon dioxide at lower atmospheres can be trapped again in the upper atmosphere where carbon dioxide had not fully saturated the absorption bands.
They also found that less absorption occurs at higher altitudes in the atmosphere. Gilbert Plass made his prediction that a doubling of CO2 in the atmosphere would cause an increase in temperature of 3.6 degrees Celsius in 1956.
He also argued that the overlapping of the absorption band at lower levels in the atmosphere with water vapor was overstated due to the more even distribution of carbon dioxide in the whole atmosphere and the concentration of water vapor at lower levels in the atmosphere.
The debate begun by Tyndall is now divided into two camps represented on one side by Knut Angstrom and his theory that CO2 plays a small role in changes to the climate and temperature and on the other by Svante Arrhenius, who believe CO2 to be a main driver in climate change and temperature.
Despite claims that the science is settled, as it relates to CO2, this is precisely the state of climate science today. We know CO2 has heat trapping properties, we do not yet know what doubling of CO2 would do to earth’s temperature.
Worried about man made carbon dioxide increases, Arrhenius believed “the slight percentage of carbonic acid in the atmosphere may, by the advances of industry, be changed to a noticeable degree in the course of a few centuries.”
By 1904, ironically, he would suggest it could benefit Earth making the climate “more equable”, and allowing for more plant growth to help feed a growing population.
“It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiment, it’s wrong.” – Richard P. Feynman
In 1896, when Arrhenius made his prediction, CO2 levels were around 290 ppm (parts per million) and the average temperature was 56.7 degrees Fahrenheit or 13.7 Celsius.
Carbon dioxide levels have now reached 400 ppm in 2017, at a rate faster than Arrhenius calculated, with a 0.8 degree Celsius increase in average global temperatures as reported by NASA Earth Observatory.
Another aspect predicted by greenhouse gas theory is an upper tropospheric hotspot. Dr. Roy Spencer, Principal Research Scientist at the University of Alabama in Huntsville and former Senior Scientist for Climate Studies at NASA’s Marshall Space Flight Center, as recently as May of 2015 has maintained that satellite and radiosonde (weather balloons) do not reveal evidence of a hotspot in the upper troposphere, but warming that is the same as surface warming measurements.
From a paper released in August of 2016 written by economist James Wallace, climatologist John Christy and meteorologist Joseph D’Aleo
“These analysis results would appear to leave very, very little doubt but that EPA’s claim of a Tropical Hot Spot (THS), caused by rising atmospheric CO2 levels, simply does not exist in the real world,”
“Also critically important, even on an all-other-things-equal basis, this analysis failed to find that the steadily rising atmospheric CO2 concentrations have had a statistically significant impact on any of the 13 critically important temperature time series analyzed.”
Thomas Stuart has been studying climate science and the global warming debate since 1996.
This is the first in a series of articles addressing the actual scientific research surrounding multiple aspects of the history of climate science.