As I mentioned in my earlier article, global warming/climate change has had a long and chequered history.
Putting aside the obvious jokes about rain dancers et al, I’ll focus on the people often cited as having given birth to the concept of, and provided evidence for, the ‘greenhouse effect’ and anthropogenic global warming (AGW). As you will often see these names used as an ‘appeal to authority’, it’s as well to have some knowledge of the back story.
An important point to bear in mind is that the early proponents of the hypothesis (also known as ‘the hothouse theory’) based much of their research on laboratory experiments. By this I mean enclosed environments where they were working on theoretical concepts and took little account of factors involved in the real world. Despite the advances in measuring and monitoring, using modern tools such as satellites and radiosondes, the whole cAGW hypothesis is still, at its core, based on experiments and calculations conducted in the early years of the last century and the tail-end of the 1800s.
Without minimising the work of those scientists mentioned on the previous page, it would be reasonable to start with those whose scientific theories have been used in forming the “cAGW myth”.
Fourier was a French mathematician and physicist born in Auxerre and best known for initiating the investigation of Fourier series and their applications to problems of heat transfer and vibrations. The Fourier transform and Fourier’s Law are also named in his honour. Fourier is also generally credited with the discovery of ‘the greenhouse effect’.
There are a couple of points to consider here.
Tyndall was a prominent 19th-Century physicist. His initial scientific fame arose in the 1850s from his study of diamagnetism. Later he studied thermal radiation, and produced a number of discoveries about processes in the atmosphere. Tyndall published seventeen books, which brought state-of-the-art 19th-Century experimental physics to a wider audience. From 1853 to 1887 he was professor of physics at the Royal Institution of Great Britain in London.
From the middle of the 1800s, Tyndall became involved in what we would now call ‘climate science’. To summarise Tyndall’s achievements you can get a taster here.
In terms of this article, let’s focus on a few points.
Arrhenius was a Swedish scientist, originally a physicist, but often referred to as a chemist, and one of the founders of the science of physical chemistry. He received the Nobel Prize for Chemistry in 1903. The Arrhenius equation, lunar crater Arrhenius and the Arrhenius Labs at Stockholm University are named after him.
Arrhenius developed a theory to explain the ice ages, and in 1896 he was the first scientist to attempt to calculate how changes in the levels of carbon dioxide in the atmosphere could alter the surface temperature through the greenhouse effect. He was influenced by the work of others, including Joseph Fourier and John Tyndall. Arrhenius used the infra-red observations of the moon by Frank Washington Very and Samuel Pierpont Langley at the Allegheny Observatory in Pittsburgh to calculate absorption of infra-red radiation by atmospheric CO2 and water vapour. Using ‘Stefan’s law’ (better known as the Stefan Boltzmann law), he formulated his greenhouse law. In its original form, Arrhenius’ greenhouse law reads as follows:
if the quantity of carbonic acid [H2CO3] increases in geometric progression, the augmentation of the temperature will increase nearly in arithmetic progression.
Arrhenius’ theory was disputed by Knut Ångström, who posited the idea that carbon dioxide and water vapour absorb infra-red radiation in the same spectral regions, thus challenging the efficacy of atmospheric CO2 as an infra-red absorber. This debate on absorption still runs today – settled science, anyone? The calculations that Arrhenius worked on were, primarily, to discover whether the Earth, via atmospheric warming, could avoid slipping back into another Ice Age. Further more he notes, a few years later, that a warmer Earth would be beneficial in attempts to feed a growing population.
Again, I’ll leave you to read the full Wikipedia entry but I’ll highlight some interesting points worth noting.
Having considered those whom, it could be said, might be credited with forming the backbone of the our modern-day obsession with ‘greenhouse gases’, we move into the modern era and consider, primarily, one key name.
Callendar was a respected steam engineer and also an amateur meteorologist. In 1938, he worked on and revived the theory of climate change based on the known effects of atmospheric carbon dioxide. He believed that rising global temperatures and rising CO2, from increased coal burning, were closely linked.
Based, at home, in West Sussex, Callendar, working with meteorological data gathered from sites around the world, produced a theory of infra-red absorption by trace gases, and then noted a correlation between rising carbon dioxide and rising temperatures. This, in due course, was christened the “Callendar effect”.
Today, when reading any MSM article relating to CO2 and the threat of cAGW, the phrase ‘a doubling of carbon emissions from pre-industrial times’ has become a standard trope pumped out with little examination of its literal meaning. These articles (should they expand into any sort of detail) then go on to quote that this ‘doubling’ is from the base figure of ~280ppm. I hope I’ve shown, in the previous post, that 280ppm cannot, by any stretch of the imagination, be classed as a rock solid foundation on which to build this hypothesis. The next section discusses how Callendar arrived at the figure quoted and why it should be treated with a certain amount of caution.
In the opening chapter of his paper, Callendar makes the following apparently simple statement;
I. THE RATE OF ACCUMULATION OF ATMOSPHERIC CARBON DIOXIDE
I have examined 21 very accurate set of observations (Brown and Escombe, 1905*), taken about the year 1900, on the amount of carbon dioxide in the free air, in relation to the weather maps of the period. From them I concluded that the amount of carbon dioxide in the free air of the North Atlantic region, at the beginning of this century, was 2.74 ± 0.05 parts in 10,000 by volume of dry air.
I would remind you of the chart on the previous page which clearly shows that this ‘pre-industrial’ level, as chosen by Callendar, and subsequently used as a basis of comparison ever since, is very much open to debate.
A search of Proceedings of The Royal Society’s archive for 1905, returns four papers submitted by Brown and Escombe in that year; Callendar refers to these studies more than once in his own 1938 paper.
These papers generally relate to the effect of CO2 on the ability of plants to complete their transpiration cycle. (If this is of interest you can find plenty of information on the Web discussing the development of high CO2 levels used by modern commercial growers.)
Of the four Brown and Escombe papers it would appear that the most significant is their study relating to CO2 levels measured at Kew Gardens. It makes interesting reading when you see the actual variations in carbon dioxide levels through the course of a year. The highest level measured during their studies was 360ppm although they treated that as an outlier due to weather conditions. Nevertheless, when someone tells you that 360ppm is unprecedented, you know what to tell them and where to find the information.
So there we have it! We appear to have constructed the whole hypothesis of cAGW on the basis of 27 determinations focussing on one specific month’s CO2 levels, over a period of 4 years, at one location (Kew).
Again we find another key cornerstone of the cAGW story that is open to critical analysis. Of course, this, in itself, is not sufficient to throw the whole concept on the scrapheap but should make one ask oneself “is the science settled?” I have no doubt that Callendar was honest in his approach to his work, and believed he had found a significant link between CO2 and temperatures, but it’s clear that he failed to take into account the possibility that natural forces drive the climate and that CO2 levels subsequently increase due to the natural warming. I have found nothing in my researches that indicate that Callendar studied any palaeontological data or considered the many earlier records of the enormous climate changes over the millennia. Many studies have since arrived at the conclusion that variations in CO2 levels can lag temperatures by several hundred years. In layman’s terms, ‘He ended up putting the cart before the horse’.
It is interesting to note the following, which underlines the limited historical research he carried out. Bearing in mind that the time-scale he was using coincided with the Earth’s recovery from the Little Ice Age, therefore, combined with the growth in human endeavour engendered by the Industrial Age, it’s hardly surprising that temperatures and carbon dioxide levels appeared to run in parallel.
Further on, in his 1938, paper Callendar states the following;
6. THE OBSERVED TEMPERATURE VARIATIONS ON THE EARTH
Coming now to the actual temperatures which have been observed near the earth’s surface during the recent past, these measurements have provided an almost overwhelming mass of statistical detail, including many millions of accurate and standardized readings of temperature. The period to which these standardized observations refer is generally not more than 65 years and often less. It is a matter of opinion whether such a period is sufficiently extended to show a definite trend in world temperatures.
I wonder how he subsequently viewed the post-war cooling and whether he reconciled that with his conviction in a coupled link between CO2 and the climate? Certainly the harsh winter of 1962-3 must have made him think. Nowadays we can fire up our computers and take stock of cyclic patterns such as ENSO (the variability of El Niño & La Niña), which appears to have a greater correlation to the climate’s changing patterns. Virtually all of the recent research funding has been focussed on substantiating the link between CO2 and cAGW and, unfortunately, not much else; Callendar’s work laid the foundation, but I would suggest he was wrong in thinking that the warming trend of his era was primarily due to human emissions.
I have no wish to diminish the work of Guy Callendar, who was instrumental in many important areas, not least in his contributions to Britain’s war effort during WWII. Although I have mentioned the limited historical climate research Callendar appeared to consider in preparing the 1938 paper, his interest in the subject didn’t wane. In 1939 he wrote a paper on “The Composition of the Atmosphere Through the Ages”. Again, in 1940, he produced a review of observations of atmospheric CO2, and 1941, a review of spectroscopic measurements of the absorption band of CO2, the pressure broadening of spectroscopic lines, and the meteorological effects of atmospheric radiation. I haven’t been able to track down the first of these. In any event, its findings have made no apparent difference to the use of his earlier work as a key setting-off point for the cAGW bandwagon.
Callendar, if working in the modern era, would be very much a bit player, as his areas of expertise, would, according to the ‘consensus’, disqualify him as a ‘climate scientist’. That comment would only apply, of course, if he were in the ‘contrarian’ camp.
A more complete biography can be found here;
There are other names that have become synonymous with the story in recent times – e.g. Keeling – but they are not quite as important in the true historical context as those I have discussed above. To gain an insight into some of the other names, and their impact, the following links provide a fuller history on the subject;
One closing remark that I would like to leave you with, and I would ask you to bear in mind, is that much of the work of scientists at the time was involved in discovering how the Earth moved into, and out of, the various glacial periods and if carbon dioxide had any controlling effect. In fact many, including Arrhenius and Callendar, felt that increasing CO2 levels would be beneficial to mankind. It has become very difficult to find anyone in the alarmist camp who will even countenance that possibility nowadays. Maybe there is some truth in the old saying;
‘Good news never sold any newspapers’.