Guest post by Tony Brown
In March 2009 Leonard Weinstein, ScD provided an interesting thesis entitled ‘Limitations on Anthropogenic Global Warming’ which was carried on The Air Vent and subsequently updated here on this link;
The author provided much interesting information but in extending the CO2 record back to 1850 naturally used the accepted ice core figures rather than contemporary readings compiled by many leading scientists of the time. These historic CO2 records show a startlingly different view to our current understanding that levels of this trace gas were constant until the 20th century, then escalated rapidly.
Figure 1; The IPCC view of CO2 variations http://climatex.org/articles/climate-change-info/climate-change-impacts-oxfordshire-words-and-pictu/
Consequently in this article I have endeavoured to look at the little known social aspects of CO2 from the 18th Century onwards, in order to demonstrate that accurately measuring this gas was a common place occurrence and that the historic records appear to show that levels have changed little over the past 200 years. As general background, the British Govt then– as now– liked to regulate industries (in this case setting CO2 levels in factories at 900ppm in 1887) and didn’t tend to stipulate legally binding regulations unless they had the means to measure, enforce, and subsequently fine transgressors
Figure 2– Historic CO2 measurements http://www.biomind.de/realCO2/
Inevitably, in trying to tie all the complex elements of the social, regulatory, and scientific story together, there is a great deal of text, links and graphs. For those with limited time to explore the past in detail I have highlighted several ‘KEY’ links which will provide some context to the development of 19th Century CO2 measurements and their subsequent discarding by the IPCC.
The early days
CO2 was not of course discovered by Charles Keeling in 1958 nor even measured by him for the first time around that date. The composition of the atmosphere and the nature of the gases within it had been well understood for many years, partially due to the special circumstances of the mining industry. Interestingly the existence of CO2 and the nature of the atmosphere was recognised as far back as ancient Rome, because of mining; (As an aside many high level Roman mines in the Alps were overwhelmed by ice as the Empire declined as the climate turned down)
Extract from this link;
“As recorded by Agricola (1), Pliny (AD 23 to 79) describes how, in Roman times, gases dangerous to humans sometimes occurred in pits and wells. He also describes how they were detected by observing the behaviour of a dog or lighted candle when lowered down the shaft. They were removed by passing a current of fresh air through the workings. In British coal mines one such dangerous gas, almost certainly being encountered by the fourteenth century, was called ‘blackdamp’ or ‘chokedamp’. This was probably in response to the fact that its presence was indicated by naked flames being extinguished and humans suffocating. Blackdamp is now recognised as occurring due to the presence underground of oxidising processes, including breathing humans, burning candles and the spontaneous combustion of coal. Thus it would have been particularly prevalent in workings not scoured by a current of fresh air drawn in from the surface.”
Increasing need for coal in the fourteenth century was undoubtedly spurred by the lurch from the MWP into much cooler times.
The existence of CO2 itself, and its proportions in the atmosphere, was identified as far back as 1756 by Joseph Black, at the start of a rapid increase of chemistry knowledge that laid the foundations for our modern understanding of the subject. The nature of CO2 and its effects were well understood by the late 1700’s and the first measurements of CO2 concentrations were carried out around that time. These became increasingly accurate as the 19th century commenced, with measurements routinely undertaken in various fields including medical, mining and industry.
As far back as March 23 1778 Scheele provided the first definitive reading of the composition of the air and commented on similarity of readings wherever they were made. The following from this document;
“One figure in this early history of air-analysis shines out above all others that of the scholarly, isolated Scheele. That Scheele may rightly be designated as the pioneer in the study of the chemistry of the air few who examine the literature can deny. His results, while admittedly of no quantitative significance, do nevertheless imply a knowledge of the chemistry of the air, of its composition, and of the possibilities of change in its composition, which was expressed no more clearly by other writers many years later.”
Around this time Cavendish made some 500 samples of air by nitric oxide eudiometer and de Saussure took daily measurements for 3 years, this evolved into the more reliable hydrogen eudiometer. These were very accurate and those scientists taking measurements from around 1800 were well aware of the importance of geography, weather, wind, season, altitude, contamination etc when taking a reading.
CO2 readings from 1790 to 1820 should be considered interesting (and possibly approximately correct) but it is from 1820 onwards that the level of reliability increased enough for us to consider a meaningful proportion of them as a useful record of their time and place. In examining a few of the measurements taken at the time later in this article, it should be borne in mind that they are a fraction of many hundreds of thousands of independent readings taken by many scientists-several of them Nobel winners-from around 1830 to the advent of readings at Mauna Loa in 1957 by Charles Keeling.
It became common place to measure CO2 from the middle part of the 19th century and ensure action if they contravened agreed safety measurements in factories or mines, as laid down in local bye laws-mostly as a ventilation issue. Readings were taken outdoors, indoors or in known hot spots–such as in cotton factories– where allowance was made for spot contamination from sources such as gas lights.
Tyndall-a famous name of course in climate science- worked with Robert Bunsen, who was one of very many who took CO2 measurements.
Tyndall gave lectures to ‘working men’ at mines in the company of Huxley, the author of a compendium of studies of CO2 called ‘Physiography- an introduction to the study of nature” dated 1888. A fascinating section from his biography follows;
“In 1859, aged 39, Tyndall began investigating radiant heat and the acoustic properties of the atmosphere. Part of his experimentation included the construction of the first ratio spectrophotometer which he used to measure the absorptive powers of gases such as water vapour, carbonic acid (Which has the formula H2CO3 and is a name often given to solutions of carbon dioxide in water), ozone and hydrocarbons. Amongst his most important discoveries were the vast differences in the abilities of “…perfectly colourless and invisible gases and vapours…” to absorb and transmit radiant heat. He noted that oxygen, nitrogen and hydrogen are almost transparent to radiant heat, whilst other gases are quite opaque.”
Tyndall’s experiments also showed that molecules of water vapour, carbon dioxide and ozone are the best absorbers of heat radiation and that even in small quantities these gases absorb much more strongly than the atmosphere itself, a phenomenon of great meteorological importance. He concluded that among the constituents of the atmosphere, water vapour is the strongest absorber of radiant heat and is therefore the most important gas controlling the Earth’s surface air temperature. He said that without water vapour the Earth’s surface would be “held fast in the iron grip of frost”. He later speculated how “changes in water vapour and carbon dioxide could be related to climate change.”
By the mid 1850’s it was becoming recognised that in some work places various processes were being carried out that were possibly injurious to the operatives. This effect was commented on by the novelist Mary Gaskell who in 1859 wrote ‘North and South’ where she described the manufacturing processes in the cotton industry. This coincided with a study by Lethbridge in 1862 that looked at the problems of carbon monoxide and dioxide.
The Cotton Cloth factories act of 1889 was subsequently enacted setting actual limits for CO2 at 900 ppm (modern commercial greenhouses operate at up to 1100ppm). Setting a legal limit had been debated in Parliament for some 20 years prior to this and the relative success of the Act subsequently observed in Hansard. (The official record of the UK Parliament)
There was also a variety of legislation enacted to control a variety of problems in mines caused by various gases, including CO2. The various Coal mines acts of 1855, 1887, 1911 refer. The 1887 act identified specific legal limits for CO2. Before the various mine acts could be passed various Royal commissions were set up and some 25 can be accessed from here, commencing in 1842. Concerns often centred round ventilation issues;
In the following book more of the background that led to the Parliamentary Act can be read (page 154 onwards) which makes considerable mention of carbon dioxide in factories and how measurements should be controlled-by-for example- taking into account the gas lighting and the processes used to power various machines. http://188.8.131.52/search?q=cache:yoxDE4U_T94J:www.victorianlondon.org/publications/westlondon-2.htm+cotton+industry+carbonic+acide+levels+victorian+era&hl=en&ct=clnk&cd=7&gl=uk
A complete bibliography of the cotton industry and the activities of the Roscoe commission -who investigated the effects of the carbon dioxide levels for Parliament- can be found here;
Throughout the 19th century the measuring methods had become increasingly accurate, commencing at the start of the century at around plus or minus 3 % until by 1850 accuracy was said to be within 0.1%. Legislation led to a rash of ever more sophisticated methods for measuring CO2, including a patent around 1895. This level of accuracy was perhaps not surprising as the basic principles of chemistry were increasingly well understood as the century had progressed. Further reference to the social elements is here-of particular relevance is the section entitled ‘The first limits’.
In due course, as more sophisticated machines for measuring CO2 came into general use, market leaders established themselves, including Haldane and Sonden Patterson of Stockholm. Charles Keeling makes references to Prof Haldane who created a highly accurate device for measuring carbon dioxide in the 1890’s which was used in mining and medical situations (exhalation), his obituary linked below confirms his knowledge of the subject.
The following is in connection with Haldane’s work for the Admiralty in measuring CO2 levels for divers;
The device he invented became a portable version and was part of the standard equipment in various organisations including hospitals, as can be seen in this inventory;
This 1912 document has already been referenced in connection with Scheele;
http://www.archive.org/stream/carnegieinstitut166carn/carnegieinstitut166carn_djvu.txt In addition there are two other famous chemistry studies of especial interest, one of which has already been mentioned;
‘Physiography: An Introduction to the Study of Nature’ by T H Huxley published in 1885, where typical values converted to ppm are generally from 327 to 380. The measurements were carried out by Angus Smith and are originally given in his book ‘Air and Rain’ published in 1872. (The 327ppm recording was taken on top of Ben Nevis, Britain’s highest mountain at some 4000 feet). (This latter book is still available for free loan from the UK library service)
So do those early observations of CO2 match other data? There are numerous bibliographies that demonstrate the considerable scientific attention being paid to CO2 at the time and it is apparent that past generations of scientists are much more knowledgeable and meticulous than the IPCC give them credit for; The following information and quotations comes from the 1912 document, except where stated;
As an aside, there was friction even then between the two sides who had their own way of taking samples and who constantly criticised each others science. Kreusler being said to having taken ‘great exception to his critics’ over his methodology to which he retorted they related to ‘but one set of samples which had already been identified as false and withdrawn.’
The following CO2 sample figures (in ppm) are from well observed locations/times and conditions; (some indoors, some countryside)
Nov 1884 036 037 039 041 050 055 0389 0391 040 044 044 048
A week later under the same criteria;
049 540 380 410 416 430 400 370 370 400 440
Feb 1885 sees a set of consistent samples from a rural area;
350 340 340 340 351 and a week later 370 350 360 340 350
In 1902 Krogh took some Greenland samples said to be accurate to .0005 to .01%. measured at 700 ppm
“In a private communication from Dr. Krogh, he reports that a series of experiments made by him in Greenland in 1908 showed oxygen percentages ranging from 20.895 to 20.980, with an average of 20.945. The unusually high carbon-dioxide percentages of former years were not obtained, (up to 700) although two observations gave 0.055 per cent. Dr. Krogh also writes that in 1907 and 1908 Dr. Lindhard of Copenhagen made observations in northeast Greenland (Denmark Haven) using the identical modified Pettersson apparatus described by Dr. Krogh in a former paper. He reports that Lindhard’s results would be liable to about 0.001 per cent error, and they agreed perfectly with those found by himself on the west coast. Lindhard generally found about 0.035 per cent of carbon dioxide, but on one or two days it was below 0.03 per cent, and on 5 days out of 23, 0.04 per cent or more. The maximum value found was 0.062 per cent.”
The very high Greenland figures (620 to 700 ppm) appear absurd and the analysis at the time says;
“The one inexplicable phenomenon is the abnormally high percentage of carbon dioxide found in the air of Greenland by Krogh.” Recent examination demonstrates that there may have been previously unidentified volcanic activity that increased the background figure.
Independent sets of samples from another scientist made in Paris in 1903 registered 300ppm and in 1910 Bay of Genoa Naples; cloudless sky; temp, on Moist 0.034
Equipment evolved quickly throughout the 19th Century; “Eudiometric observations were exclusively relied upon during the first 50 years of the development of air-analysis, but later gravimetric methods were introduced by Brunner and Dumas in which the oxygen was absorbed by copper or phosphorus, and was subsequently weighed. Then there followed a return to the hydrogen-explosion method, which was advanced to the highest degree of accuracy by Bunsen, Regnault, Frankland and Ward, and Morley. Meanwhile the interesting method of Liebig, employing an alkaline solution of pyrogallic acid, and the copper eudiometer of von Jolly made their appearance.”
“Of particular significance is the fact that analyses made on the same samples sometimes showed extremely high values for carbon dioxide, ranging at times from 0.025 to 0.07 per cent.”
(Definition; The art or process of determining the constituents of a gaseous mixture by means of the eudiometer, or for ascertaining the purity of the air or the amount of oxygen in it.)
The document referenced provides hundreds of pages of equipment, techniques, samples readings and tips on ensuring maximum accuracy of readings.
“While the investigation was started primarily to study the oxygen-
content of the outdoor air, it was necessary to determine beforehand the carbon dioxide, since an alkaline absorbent for oxygen was employed; hence practically all the analyses are accompanied by simultaneous determinations of the carbon dioxide in the air. In the especially exact apparatus designed by Sonden and Pettersson, the carbon dioxide is determined to the third or fourth significant figure, but as the amounts of carbon dioxide that were to be used in our apparatus might at times reach 1 per cent, it was impossible to secure this degree of fineness in the calibration of the carbon-dioxide pipette, hence readings can be taken only to one-thousandth of 1 per cent. Consequently, since other methods are better adapted for securing accurate carbon-dioxide determinations, little stress has been laid upon the determinations made in connection with this research, although they are probably accurate to within 0.002 in all cases. The routine outlined was followed with practically no modification from April 5 up to Nov. 3, 1909. “
There then followed a long series of hourly and daily recordings observed in the referenced book, a fraction of which are reproduced here;
Table 50. Results obtained on sample of outdoor air with
first routine, April 5, 1909, 11 h 45 m a. m. 0.029 0.031
Table 51. Analyses of outdoor air made at the Nutrition Laboratory. 1 Series
1909. Apr. 5 onwards almost daily to June 3 and virtually every hour
Then Oct. 18 to December
0.031 .032 .028 .026 .029 .030 .027 .030 .027 .029 .030 .029
.030 .031 .032 .030 .031 .031 .031 .032 .032 .030 .030 .032 .030
.028 .028 ‘.028 .029 .029 .031 .028 .030 .029 .029 .029 .031 .029
.028 .030 .029 .031
Another series Table 52. Results obtained on sample of outdoor air with
second routine, November 4, igog, g b /o m a. m. 0.035 0.036
1909 Pleasant, warm and sunny.
0.034 .033 .034 .031 .029 .028 .029 .031 .032 .033 .032 .030 .030
.031 .031 .031 .032 .034 .032 .029 .031 .032 .030 .030 .028 .033
.031 .031 .030 .028 .028 .028 .028 .029 .030 .028 .031 .031.030
.030 .031 .030 .028 .033 .032 .032 .034 .030 .032 .033 .030 .029
.028 .030 .028 .030 .029 .030 .028 .030 .029 .030 .031 .031 .033
.030 .030 .033 .031 .032 .031 .031 .031
An experiment had to conform to strict criteria;
“…. would be thoroughly mixed and have a fairly constant composition. Employing precisely the same technical routine, samples of the cylinder air were frequently analyzed as a control on the analyses of the outdoor air.” The results of these analyses made between December 3, 1910, and February 9, 1911, are given in table 54.
1911. Dec. 9 2 56 p.m..032
Jan. 21 2 32 p.m. .031
Dec. 10 10 14 a.m. .031 3 43 p.m. .033
Dec. 13 12 02 p.m. .034
Jan. 23 9 37 a.m. .032
Dec. 15 11 52 a.m. .031 10 52 a.m. .033
Dec. 22 2 31 p.m. .033
Jan. 31 10 03 a.m. .032 3 43 p.m. .033
11 30 a.m. .033 4 52 p.m. .034
Feb. 9 .034
At this stage it became pointless to continue recording the information of thousands of samples, as the figures consistently show readings of up to around .034 or so throughout the daily readings made in Dec 1911 through to 1912- the measurement records can all be seen in the document referenced and confirmed in the various bibliographies available;
“The results of analyses of air taken near the laboratory showed no material fluctuation in oxygen percentage during a period extending from April 15, 1911, to January 30, 1912. This constancy was maintained in spite of all possible alteration in weather conditions, changes in barometer, thermometer, humidity, and wind direction and strength; furthermore, the experiments were made before, during, and after the vegetative season. The average result of 212 analyses showed 0.031 per cent of carbon dioxide and 20.938 per cent of oxygen. The analyses of air collected over the ocean, at two different times of the year, and on the top of Pike’s Peak, gave essentially similar results. The average results of all the analyses made in this research of outdoor air are summarized in table 72.”
That CO2 readings became commonplace in Victorian times can be seen here;
“It will be seen, therefore, that since there are a number of simple and accurate methods for determining carbon dioxide, so the time-consuming and complicated determinations of oxygen are entirely unnecessary.”
Comment on Methodology; “The wisdom of taking samples dry is seen from these results, since in all dry samples the percentage of carbon dioxide was found to be always normal.”
These apparently higher than expected historic CO2 figures are noted by this separate study in 1981;
“Abstract from articles The longest continuous record of measurements of atmospheric CO2 concentration available to date, that was made between 1877 and 1910 at the Montsouris Observatory in the outskirts of Paris, is presented and the methods used and the site are described…..
….Mean decadal values of the Montsouris series show a marked rise in concentration from 283 ppm in the first decade to 313 ppm in the second, with a small and non significant drop to 309 ppm in the third decade of the series. The results of the measurements are thus compatible with the hypothesis that a major and variable non-fossil fuel source of atmospheric CO2 was active during the last quarter of the nineteenth century.”
The link below leads to a 1917 study where the means to analyse CO2 is taken as the norm and viewed as a simple procedure. http://www.jbc.org/cgi/reprint/33/1/47.pdf
That CO2 levels can vary considerably in a year (readings taken weekly and averaged at Mauna Loa) might be surprising, but it does occur;
The above study by Keeling, (for example a location in Canada) ranges from 360 to 378ppm (seasonal changes amongst others)
The article from the following link examines the concept of urban CO2 domes and contains an interesting diagram;
Extract; “Idso et al. (1998a) measured air temperature, relative humidity and atmospheric CO2 concentration at a height of two meters above the ground at approximate 1.6-km (1.0-mile) intervals prior to sunrise and in the middle of the afternoon across four transect routes through the metropolitan area of Phoenix, Arizona, during a five-day period in January of 1998. These data revealed the presence of what they called an “urban CO2 dome,” the two-meter-height atmospheric CO2 concentrations of which were found to be as high as 555 ppm at the center of the city.”
The apparent considerable natural variation in CO2-see figure 3-due to ocean to air exchange (amongst other factors) puts the apparently irrational variable figures from the 19th Century onwards into context, yet IPCC AR4 suggests a remarkably constant 285ppm at this time, despite the expected outgasing and inflow caused by variability in ocean temperatures. The IPCC icon is Mauna Loa so it is instructive to go to the oracle so see what that says about variability;-this link shows how observations are made in general;
The following link goes into more detailed specifics;
Figure 4 shows the range of the mole fraction in ‘scatter’ measurements whilst figure 5a demonstrates real world conditions and the variation of CO2 in the atmosphere shown in the top part of that graph, and in the bottom section the effect when averaged out over a day, so the 335ppm to 368ppm again puts the observed variability in the historic samples in much better context. The overall effect of taking CO2 measurements at Mauna Loa situated on top of an active volcano at over 3000 m altitude and surrounded by a constantly outgasing warm ocean shall be left to others to debate, but the averaging disguises the considerable daily variability.
Outgasing of CO2 occurs when oceans are warm, interestingly the 1912 readings mentioned earlier contains this note;
“When the air-analyses were resumed in the fall, after a summer of unprecedented heat in Boston…”
“ANALYSES OF AIR FROM PIKE’S PEAK. (14000 feet altitude)
The interesting expedition to the top of Pike’s Peak made by Haldane,
Yandell Henderson, Douglas, and Schneider, in the summer of 1911, was
utilized in that these gentlemen kindly consented to collect samples of air for this research….possibly resulting from the extreme heat of the summer, which had been abnormal for this section.”
There are a number of interim observations we can make before examining in the next section as to why the figure of 280ppm pre industrial became the accepted norm.
* From Victorian times readings were taken widely and frequently
* Measurements were taken by established scientists using reliable methods
* Levels consistently show around 310 and above-with 330/350 frequently attained
* CO2 levels varied considerably throughout the period 1820-1957
* Allowance was made for possible disruptions to readings-for example sources of CO2 were identified-such as from gas lamps
*European CO2 levels immediately prior to the commencement of the Keeling data in 1957 appeared to be around 30ppm higher than he recorded
*Averaging disguises the ranges.
*The current levels of CO2 are not unprecedented if the historic records are accurate
Section Two How 280ppm became the accepted pre industrial norm.
At this stage it becomes necessary to examine why 280ppm became the figure accepted by the IPCC, even though there was overwhelming documentary evidence to show this figure was rather on the low side, and levels were anyway subject to much more fluctuation than modern records seem to indicate. (This paper does not go into the separate subject as to whether temperature rises first, followed by increased CO2, or the timescale of cause and effect)
Anyone reading the following should put themselves into the mindset of those creating the science of CO2 measurements from the 1950’s who were especially influenced by the measurements taken by an amateur meteorologist-G S Callendar- some years previously. The accessibility of data should also be taken into account-we take instant information for granted and can make ready comparison with numerous sources at the touch of a button. In making these caveats we look at this extract from the Book ‘The Callendar effect’ as this gentleman is known as the Father of the AGW theory and is someone who greatly influenced Charles Keeling.
“Callendar’s 1938 paper did not include a citation of Arrhenius’s 1896 paper, although there are many parallels between the two. Callendar analysed just one set of data on atmospheric CO2 content taken at Kew, near London, between 1898 and 1900. These data were taken near a source of CO2 and were analytically very uncertain. From this analysis, he concluded that at around 1900 the free atmosphere over the North Atlantic region contained 274 ± 5 parts per million (p.p.m.) of CO2. Then, after arguing that only a small fraction of the CO2 from combustion of fossil fuels would dissolve in the ocean, he calculated from an estimated global production rate of CO2 the amount that he thought would be there in 1936 (290 p.p.m.), 2000 (314–317), 2100 (346–358) and 2200 (373–396).
With a simple model of the absorption of infrared radiation, he worked out the amount of global warming to be expected from his predicted CO2 levels, concluding that temperature would then have been increasing at a rate of about 0.03 °C per decade. Callendar’s 1938 attribution of early twentieth-century warming to CO2 increase might have been believable if global cooling had not ensued in the 1960s and 1970s.”
Callendar was a noted amateur meteorologist and steam engineer. After reading his papers-and corresponding with him-Keeling used that research as the basis for his own estimates of CO2. From Callendars biography;
“In 1944 climatologist Gordon Manley noted Callendar’s valuable contributions to the study of climatic change. A decade later, Gilbert Plass and Charles Keeling consulted with Callendar as they began their research programs. Just before the beginning of the International Geophysical Year in 1957, Hans Seuss and Roger Revelle referred to the “Callendar effect” — defined as climatic change brought about by anthropogenic increases in the concentration of atmospheric carbon dioxide, primarily through the processes of combustion.”
Callendar examined 19th and 20th century CO2 measurements, and rejected those he considered inaccurate for a variety of reasons, the ones he selected led him to conclude that the pre-industrial CO2 level was about 290 ppm (G. S. Callendar, “The Composition of the Atmosphere through the Ages,” The Meteorological Magazine,vol. 74, No. 878, March 1939, pp. 33-39.) This seemingly low 280/290ppm figure is important, as it is the one that Charles Keeling subsequently accepted.
Among the criteria that Callendar used to reject measurements were any that deviated by 10% or more from the average of the region, and any taken for special purposes such as such as “biological, soil, air, atmospheric pollution”. The first criteria is said to be a rather circular argument, while the second seems to ignore the accuracy of the results. Whatever the validity of these exclusions, it turned out that the mean of 19th century samples he chose to include was 292 ppm. The mean of the samples he had available to include was 335-350 ppm (although these would have been towards the top end of the spread).
Selecting measurements from the low end of the spectrum was robustly justified in the article Fonselius and the history of CO2 measurement carried here;
Extract; “Fonselius et al. go on to discuss how CO2 measurements might be improved and collection extended, remarking that in the diagram,(contained in the link) the values used by Callendar and our mean values are encircled and we can see that our values fit in quite well.
This analysis seems at variance with the information now available and that Keeling later came to believe in the accuracy of the old measurements he had previously rejected as being too high is demonstrated in his own autobiography. Ironically Callendar in the last years of his life also doubted his own AGW hypothsesis. Similarly whilst Arrhenius’ first paper on the likely effect of doubling CO2– with temperature rises up to 5C– is often quoted, his second paper ten years later– when he basically admitted he had got his initial calculations wrong-is rarely heard. In this latter paper he estimated a figure of 0.7C for doubling, although the base CO2 measurement used might be contentious.
During the 19th century –and up to 1957 with the inception of the monitoring station at Mauna Loa– it was widely accepted that the ‘normal’ level for Co2 was 400ppm. As already mentioned the catalyst for overturning this long held belief was Callendar’s seminal paper in 1938 linking CO2 in the atmosphere with mans emissions of the gas and rising temperatures. This is the Callendar document concerned in its original 1938 book form; (KEY LINK)
After perusing Callendars’ extensive archives (available on DVD) his thought processes can be clearly followed in the numerous notes he made. He had compiled his theory and like many with a mission wanted to ensure the evidence supported it. The comment by Coste (see below) can not be beaten, as clearly Mr Callendar had been considered by his peers-if not by ‘someareboojums’- to have been highly selective in deciding which CO2 readings to use. The Callendar paper was severely criticised at the time-none more eloquently or politely than in this paper by renowned US meteorologist and science writer Giles Slocum who wrote a critique of it in 1954;
“At the time Callendar delivered his 1938 paper Mr J H Coste suggested that the accurate CO2 content at the turn of the century had been considered to be about 0.04 % and not the 0.029% indicated by the measurements cited ….and asked can we be sure that there has been any net increase at all?”
The elegant demolition of the Callendar theory -that man had increased CO2 readings from a constant 280ppm since pre industrial times-is linked below. (KEY LINK)
Those inclined to agree with the supposition that CO2 is a gas that varies substantially in concentration will be intrigued by this note recorded in Slocums’ paper as follows
“Since Callendar by basing his hypothesis on statistical data has tacitly invented the laws of statistical evidence, it is fitting to examine the validity of his procedure, that of using only the data he believed to be of the best quality available, rejecting the rest.”
The tiny annual linear increase in CO2 concentrations as recorded at Mauna Loa seems surprising, as it might be reasonably expected to reflect the considerable variations measured prior to 1957 which seems to reflect the size of the natural CO2 flux-particularly with the oceans– as can be seen in figure 3.
The interchange of CO2 was thoroughly discussed in this paper by Roy Spencer http://wattsupwiththat.com/2009/05/12/spencer-on-an-alternate-view-of-co2-increases/
All of which serves to illustrate that modern readings are at complete variance with the older ones, both in terms of concentrations and also as regards the degree of variability. The main case for the modern belief in the validity of Callendar’s figures –reflected in the Mauna Loa readings-lies in two pieces of evidence.
Modern evidence for escalating levels of CO2
The first concerns ice core readings which are said to confirm the pre industrial level of 280ppm. The linked paper is a detailed examination of how ice core samples are made and goes into the complexities of fractionation, whereby CO2 bubbles trapped in ice may become contaminated by levels from a different time scale.
The analysis of ice cores is a new and complex science that gives proxy readings many hundreds (and hundreds of thousands) of years after the event. Ice core accuracy is hotly disputed by such as Professor Jaworowski in this link;
Professor Jaworowski was comprehensively dismissed in this article
Carried here http://www.someareboojums.org/blog/?p=7
Extract; “To honor exceptional achievement in mendacity, I would like to present the Golden Horseshoe Award to that writer who has out-performed his or her peers in density of false statements per column-inch. To receive the first Golden Horseshoe Award, I can think of no more worthy recipient than Zbigniew Jaworowski.”
Jaworowski’s paper certainly had its faults but hardly warranted this sort of treatment.
At the start of this article I referred to Leonard Weinstein’s, ScD excellent and comprehensive thesis entitled ‘Limitations on Anthropogenic Global Warming’
This explores ice core methodology in some detail under the sub heading; “The Question of Reliability of Older CO2 level determination” from which this informative extract is derived:
“CO2 determined from glacier ice core gas bubbles has been used to indicate the atmospheric CO2 level at the time the bubbles formed. The frozen core sample is crushed to obtain the trapped gas from the bubbles and directly find the CO2 concentration. There is no direct supporting evidence that this is a valid technique. In order to examine the reasonableness of the process, the following discussion examines three possible issues.
The first issue arises from the porous nature of the compressing ice, which may take from about a hundred years to possibly as long as thousands of years before it seals off completely. This would result in diffusion averaging of composition, and very likely lose resolving even large variations in atmospheric CO2 occurring over shorter periods than the time to seal off. This is probably the cause of the near constant indicated CO2 composition over long periods.
The second issue arises from the comparison of levels and trends of CO2 made by other techniques. In particular, a set of measurements was made using the inverse relation between atmospheric carbon dioxide concentration and stomatal frequency in tree leaves to provide a method for detecting and quantifying century-scale carbon dioxide fluctuations (Wagner, F., Bohncke, S.J.P., Dilcher, D.L., Kurschner, W.M., van Geel, B. and Visscher, H. 1999. Century-scale shifts in early Holocene atmospheric CO2 concentration. Science 284: 1971-1973.). The results indicated CO2 levels varied considerably over the last several thousands years, and in some cases came much closer to present high levels than indicated in ice cores (to at least as high as ~348 ppm). In fact, a significant part of the difference between stomatal frequency based data and ice core data may be related to the first issue above.
The third issue relates to the CO2 content of trapped air being selectively reduced by dissolving in either a quasi-liquid or liquid layer. According to an article by John S. Wettlaufer and J. Greg Dashbears at: http://www.bushwalking.org.au/FAQ/FAQ_MeltBelowZero.htm
“Ice has a quasi-liquid film, a natural state of solid ice formed by a process called surface melting, at temperatures down to near –40OC”. This layer has some structural characteristics of the solid below it but has the mobility and solubility of a fluid. This layer can contain dissolved gases such as CO2. In addition, there is the possibility of some liquid water being present in the ice even at temperatures below normal freezing. The rise in summer temperature and prolonged sunlight could even form melt layers (possibly subsurface) during glacier formation. When the melt liquid forms, the high solubility in the liquid could preferentially (compared to O2 and N2) take in a significant quantity of CO2. At release of pressure, when cores are drilled and raised, there could be some preferential CO2 loss from the micro cracks in the cores, or the ice could retain excess CO2 separate from the air bubbles.
Conclusions from the above are:
1. The process of the formation of glaciers may result in temporal smoothing of results on a time scale long enough to miss large level variations of CO2 lasting possibly hundreds of years.
2. Some alternate techniques that determine CO2 concentration over time contradict the slow changing ice record, but this may in fact be due to 1). This could mean present levels are not quite so extremely high or unusually fast changing as thought.
3. Quasi-liquid films and liquid water occurring during glacier formation could be a significant source of CO2 removal from trapped air bubbles, especially near the freezing point. Significant amounts of CO2 may preferentially dissolve even in a small amount of quasi-liquid or liquid. This could result in a preferential reduction of the CO2 concentration in the larger gas bubbles.
The final result is not a demonstration that the results are wrong, but that there is some room for doubt for the reliability of ice core bubble composition to determine older CO2 concentrations in air, and a more reliable method to determine older CO2 atmospheric concentrations is badly needed.”
Certainly the question marks hanging over the complexities of this aspect of climate science does not enable this proxy method to automatically trump the observations of 130 years of direct measurement from 1830 up to Keeling’s own series of analysis commencing in 1957.
The second proof used to discount historic readings comes from analysing the man made ‘fingerprint’ of modern CO2;
“CO2 emissions coming from the use of fossil fuels will be comparatively poorer in carbon 13 (especially for coal, less for oil and gas) but will be exempt of carbon 14, as explained above.
It is now observed that the atmospheric CO2 is getting poorer in carbon 14 and in carbon 13. The decrease of the proportion of carbon 13 indicates that the increase of CO2 in the atmosphere can’t come from the ocean (otherwise the atmospheric CO2 would get richer in carbon 13), and the decrease of the proportion of carbon 14 implies – as it is the only possibility – that emissions deriving from the use of fossil fuels contribute to the accumulation of CO2 in the atmosphere.”
However this paper puts the data into a different context;
Extract; “For principal verification of the adopted PSR model, the data source used was the outcome of the injection of excess 14CO2 into the atmosphere during the A-bomb tests in the 1950s/1960s, which generated an initial increase of approximately 1000% above the normal value and which then declined substantially exponentially with time, with τ = 16 years, in accordance with the (unsteady-state) prediction from and jointly providing validation for the PSR analysis. With the short (5−15 year) RT results shown to be in quasi-equilibrium, this then supports the (independently based) conclusion that the long-term (100 year) rising atmospheric CO2 concentration is not from anthropogenic sources but, in accordance with conclusions from other studies, is most likely the outcome of the rising atmospheric temperature, which is due to other natural factors. This further supports the conclusion that global warming is not anthropogenically driven as an outcome of combustion. The economic and political significance of that conclusion will be self-evident.”
So the historic records have not as yet been irrevocably disproved by modern evidence and deserve serious re appraisal. The person who has carried out the most detailed scientifc examination of historic CO2 measurements is Ernst Beck, whose web site is linked here. It has many diasgrams, graphs, (from which Figure 2 came) and numerous links to contemporary papers which appear to demonstrate that CO2 was accurately measured back to 1830 at levels substantially higher than the IPCC currently concedes. (KEY LINK) http://www.biomind.de/realCO2/
One of the most rational opponents of Becks historical records and a proponent of the accuracy of ice cores and mans carbon fingerprint is Ferdinand Engelbeen. His web site contains much interesting information on all these aspects, although interestingly he remains something of a sceptic. KEY LINK
This article has of necessity been wide ranging in order to give a reasonably comprehensive overview of the subject with information from both sides of the debate. The author has looked at the social aspects-whereby CO2 measurement was a common occurrence from the early part of the 19th Century; the quality of the scientists concerned and accuracy of their methods; is aware of the growing knowledge of the chemistry of the atmosphere from that time; read the scepticism shown by many such as Giles Slocum; examined the manipulation of records by Callendar ;the endorsement of these selected figures by Charles Keeling and its acceptance by the IPCC without any real attempt to analyse the past, and finally examined the material that is said to disprove the validity of the old measurements.
Clearly if a constant CO2 level of 280 ppm had existed it should give a pretty constant climate through history and the Met office confirms this as follows;
Extract “Before the twentieth century, when man-made greenhouse gas emissions really took off, there was an underlying stability to global climate. The temperature varied from year to year, or decade to decade, but stayed within a certain range and averaged out to an approximately steady level.”
However this statement directly contradicts our accepted view of the world before Michael Mann, the IPCC and the Met office came along, as observations, numerous written records, plus actual instrumental records from the past do not confirm this bold assertion. Clearly temperatures did vary considerably in the past and if CO2 is a powerful climate driver it should surely move in unison with them-albeit the time lag of cause and effect is controversial.
Drawing on our knowledge before post modern climate science gained ascendancy, it is evident that even during the Little Ice age -which commenced around 1300- there has been considerable fluctuations in temperature to levels much colder than- and around as warm as– today, a period largely covered by this graphic;
If this chart could be extended back from 1300AD to around 800AD it would cover the Medieval Warm Period with temperature levels somewhat higher than today, but again with its peaks and troughs. The Roman optimum warm period-around 300 BC to 400AD would also show temperatures at similar levels to the MWP but again with peaks and troughs. (Few extended climatic periods are unremittingly warm or cold). The modern era of temperature measurements starts at 1850 (CRU) and 1880 (GISS) each coinciding with a downturn reflecting the last outbreaks of LIA conditions. Temperatures have trended up slowly since the low point of the LIA in the 1600’s
Actual instrumental records can be usefully represented by Central England Temperatures to 1660, a set described by Hubert Lamb first director of CRU as being a good reflection of the Northern Hemisphere and to a lesser degree global trends. The following link contains a graph showing CET.
Clearly the instrumental record appears to pick up much more temperature variation than it might be thought should occur with CO2 at a constant 280ppm pre–industrial (1750) or at 295ppm in 1900 and rising steadily to today’s values of 380ppm – a level said to be causing unprecedented warming. Looking at the climatic peaks and troughs illustrated in the graph stretching back from the modern era-and extending it with figure 4 through the LIA- it is a reasonable conclusion to draw that either CO2 is a weak climate driver, or that history has erased higher CO2 measurements that might explain those variations prior to the last half century, when our emissions are thought to be of such a significance that they are changing our climate.
This latter supposition was the approach I took in plotting a fraction of Beck’s records (shown as green dots) against CET records back to 1660 which appear on the graph linked above. Total cumulative man made CO2 emissions throughout this period are represented by the blue line along the bottom and come from CDIAC.
The temperature spikes make much more sense with these additional CO2 measurement points, and bearing in mind the well documented temperatures back to Roman times and beyond-to levels greater than and less than today- it is reasonable to conclude that in as much CO2 is a contributor to the climate driver mechanism, it is as part of natural CO2 variability within the overall carbon cycle whereby nature makes a far greater contribution than man.
We have a clear conundrum as the C13 C14 human fingerprint together with ice core analysis appear to directly contradict the work of our meticulous and conscientious forefathers who constantly strove to drive science forward. To dismiss historic CO2 records as irrevocably flawed and believe that modern science is perfect is to forget the lessons of the recent past. Climate Gate has shone a bright light onto surprising practices and the IPCC has lost credibility as the sole and infallible arbiter of climate science.
Consequently, I tend to believe that those who compiled the historic CO2 measurements present a more compelling case than modern evidence and would be confident that a significant percentage –but by no means all– of these historic CO2 records have an acceptable degree of accuracy, and that past levels were similar to today and fluctuated much more than we currently believe-possibly as natural temperature variations caused considerable interchange between ocean and atmosphere-an effect which dwarfs any input by man.
At best the case is ‘not proven’ as Scottish law might say, which seems surprising bearing in mind the fundamental importance of this measurement to the proposition of man made global warming. At the least-like global temperature records-the numerous historic measurements of CO2 warrant an independent audit.
My own web site which examines historic instrumental temperature records back to 1660 is linked here; http://climatereason.com/LittleIceAgeThermometers/