Atmospheric Concentration of Carbon Dioxide

Early chemical measurements of the concentration of carbon dioxide in the earth’s atmosphere have been suppressed by the Intergovernmental Panel on Climate Change. 

Chapter 1 of the IPCC Fourth Report (1), entitled “Historical overview of Climate Change Science” makes no mention of any early measurements. 

Weart (2) in his “History of the Carbon Dioxide Greenhouse Effect” also makes no mention of them. 

Yet Beck (3) has provided an annotated list with links to internet access of almost 200 references to peer reviewed academic scientific journal articles containing some 40,000 measurements of atmospheric carbon dioxide by chemical methods between 1800 and 1960. Comprehensive data sets in more than 390 papers were ignored despite contributions from prominent scientists like Robert Bunsen, Konrad Roentgen, and J S Haldane or the Nobel Prize winners August Krogh and Otto Warburg. 

The earliest listed publication in 1800, and others from 1809-1816, are by Theodore de Saussure. He was the son of Horace-Benedict de Saussure, who invented the Hot Box (which resembled a greenhouse) which was the basis of the theory of the climate developed by Jean Baptiste Joseph Fourier in 1822 and 1824 which is claimed to have originated the greenhouse effect. Yet the measurements of atmospheric carbon dioxide by de Saussure’s son are completely ignored. 

Other early references by Letts and Blake 1802 and 1719-15 from The Royal Dublin Society give an additional list of early measurements. 

Beck (4-5) has published several summaries and commentaries on the early measurements and include an argument with Ralph Keeling (6). 

Most of the early measurements were from Northern Europe. Beck considered that the earliest measurements were subject to various errors but the widespread use of more reliable equipment, particularly the Pettenkoffer titrimetric method in 1812 led to high accuracy, with a maximum 3{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} error reducing to 1{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} for the data of Henrik Lundegardh (1920–26).

The measurements selected by Beck were from rural areas or the periphery of towns, under comparable conditions of a height of approx. 2 m above ground at a site distant from potential industrial contamination. They showed a variation with time of day, of season, and of wind speed and direction, making it difficult to derive a local average, There were frequent measurements of concentrations higher than those reported as background concentrations by NOAA at present. 

These measurements were carried out by real people with proper instruments in a large number of localities. They give a much better appreciation of variability and change in atmospheric carbon dioxide concentration over the period than the deductions from gas trapped in ice cores which are from unrepresentative locations and subject to much uncertainty (7).

In 1958 Charles Keeling, introduced a new technique for the accurate measurement of atmospheric CO2 using cryogenic condensation of air samples followed by NDIR spectroscopic analysis against a reference gas, using manometric calibration. Subsequently, this technique was adopted as an analytical standard for CO2 determination throughout the world, including by the World Meteorological Association. 

The climate models sponsored by the Intergovernmental Panel on Climate Change are based on the belief that the global climate has a “balanced“ energy which is only changed by increasing concentrations of carbon dioxide and other greenhouse gases. These gases are assumed to be well-mixed so that their concentration, all over the world, is a constant at any one particular time, increasing only with human emissions.

In order to support this theory Keeling at the Scripps Institution of Oceanography,“discovered” that there was an almost consistent “background” concentration of carbon dioxide which could be identified from suitable sites and shown to increase with carbon dioxide emissions, which could be considered to apply globally. 

The procedure required to identify this background is described in some detail by Tans and Thoning (8)  for the observatory at Mauna Loa. 

Measurements whose standard deviation fell below a specified minimum were rejected. On average, over the entire record, there are 13.6 retained hours per day with background CO2. The rest were rejected as “noise”. 

Beck (9) has discussed the Mauna Loa measurements. Comparison between old wet chemical and new physical methods in 1958 and 1967 on sea and land give a difference of about +10 ppm for the new procedure.

A similar procedure has been described for New Zealand (10).

At Baring Head maritime well mixed air masses come from the Southerly direction, and a baseline event is normally defined as one in which the local wind direction is from the South and the standard deviation of minute-by-minute CO2 concentrations is <<0 .1=”” 6=”” font=”” for=”” hours.=”” more=”” or=”” ppmv=””>

This “background” concentration is supposed to be well-mixed and to be unaffected by sources and sinks.

Yet the oceans are themselves contaminated with sources and sinks. (11)

 

The region around Mauna Loa includes areas with CO2 emissions, and much of the rest is a sink. It is understandable how difficult it is to get a sufficiently constant sample. 

In order to claim that there is such a thing as a background CO2 it has been necessary to ensure that all measurements everywhere in the world are made from samples from over the oceans. Measurements over land surfaces have been comprehensively discouraged. 

Yet the greenhouse effect is about emissions, namely “contamination” It is crazy, to take all this trouble to make measurements which do not involve the emitted gases themselves, but only a small fraction that is considered to be well-mixed, then to claim that it is these background figures which apply to the entire atmosphere.