Pricking the Sky Dragon – Slaying the Sky Dragon Excerpt
The life of a climate skeptic is no holiday. We battle against a well-entrenched public misconception that is supported by most of the media and politicians. When we are invited to lecture on our “heresy” or to debate somebody that supports the conclusions of the Intergovernmental Panel on Climate Change (IPCC), we have to be prepared with ironclad arguments and equipped with scientific sources beyond reproach—and still we are frequently perceived as loonies. To wit, there is little fun in a skeptic’s career (but, to quote Gimli the Dwarf: “Certainty of death, small chance of success … What are we waiting for?”)—and one of the highlights of mine was being invited to contribute to the Slayer volume.
Recently (in October 2010) I published a considerably less ambitious skeptic’s book of my own in Slovenian: Podnebna prevara (The Climate Fraud, www.orbis.si). I was in the final editing process when news of the forthcoming Slayer book was announced, so I sought to establish contact with the authors to get a sneak peak at the material; I wanted to check whether I had made any blatant errors in my own work (I did not). After my book was already in print, I happened to come across the following little piece of “scientific consensus” that the IPCC flies by, so my first thought was to share it with Claes Johnson.
My involvement with the isotopic argument started when a fellow skeptic from the US became involved in a debate about the causes of global warming (a.k.a. climate change) and his opponent advanced the argument that CO2 from human activity—such as coal combustion—can be distinguished from “natural” carbon dioxide even far away from its emission, citing the IPCC’s Fourth Assessment Report (AR4) as the source.
In view of past practice of the IPCC—especially after Climategate—AR4 hardly seems to be an adequate corroborative source. It is pretty much as though the government of the People’s Republic of China cited proceedings of the Chinese Communist Party congress in support of its policies. Lest I be accused of misapplication of logic, let me make myself clear: the fact that AR4 is cited in support of an IPCC claim (or the proceedings of the Chinese Communist Party congress cited in support of Chinese government policies) does not make the claim false, but it offers no new information; it seems reasonable to assume that all IPCC publications support the IPCC’s claims (as all decisions of the Chinese Communist Party support the policies of the Chinese government).
Setting aside the above caveat, the AR4 “The Physical Science Basis does state the following on page 139 (“Chapter 2. Changes in Atmospheric Constituents and in Radiative Forcing”):
“The increases in global atmospheric CO2 since the industrial revolution are mainly due to CO2 emissions from the combustion of fossil fuels, gas flaring and cement production.” [1]
In addition, on page 139, there is an explanation of how CO2 from combustion of fossil fuels could be differentiated from other sources:
Emissions of CO2 from coal, gas and oil combustion and land clearing have 13C/12C isotopic ratios that are less than those in atmospheric CO2, and each carries a signature related to its source. Thus, as shown in Prentice et al. (2001), when CO2 from fossil fuel combustion enters the atmosphere, the 13C/12C isotopic ratio in atmospheric CO2 decreases at a predictable rate consistent with emissions of CO2 from fossil origin.
The substantiating source – Prentice et al. (2001) “The Carbon Cycle and Atmospheric Carbon Dioxide” – is an article in the IPCC’s Third Assessment Report (TAR, 2001), but we have already set such reservations aside.
For any reader that might be unfamiliar with isotopes, a brief explanation is in order. Carbon occurs in three types of atoms: 99{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} is the most common 12C with six protons and six neutrons in its nucleus, 1{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} is the slightly heavier 13C with six protons and seven neutrons, and the third isotope, 14C with six protons and eight neutrons, accounts for only 0.0000000001{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} of carbon atoms. It is unstable with a half-life of 5,730 ± 40 years and, although it is essential for determining the age of organic matter, it plays no further part in our story. All carbon isotopes are chemically identical, they differ only in weight.
However, when different isotopes are involved in biochemical reactions, it is quite common for a “bias” against heavier atoms to come into evidence. One might consider the following analogy: if a rational worker were presented with a pile of stones and told nothing more but to carry half of them up a flight of steps, it is likely that he or she would be “biased” against the heavier stones and that the new pile would contain more smaller stones than the average of the original heap.
Prentice et al. (2001) relies on measurements that clearly show such a “bias” in plants. Specifically, bodies of plants with C3type metabolisms contain (on average) 99.12{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} 12C carbon and 0.88{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} 13C, as compared to the atmospheric ratio of 99{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} 12C vs. 1{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} 13C. Prehistoric giant ferns and other plants that carbonized over eons into coal had a C3-type metabolism and therefore combustion of coal introduces CO2 into the atmosphere that contains 0.12{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} less of the 13C isotope; therefore, if present in sufficient quantities, this would eventually decrease the atmospheric concentration of 13C below 1{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117}. Prentice et al. (2001) makes the claim that such a decrease in atmospheric content of the 13C isotope has in fact been recorded in the Mauna Loa CO2 measurements from 1980 to 2005, and that therefore this must be due to human emissions of CO2 from combustion of fossil fuels.
However, there is a problem. C3-type plants are not extinct; in fact, they make up 95{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} of the mass of all current plant life!
Therefore, decay of 95{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} of present-day plant material also emits the 13C-deficient carbon dioxide supposedly characteristic of coal combustion—and CO2 emitted by plant decay is an order of magnitude greater than all humangenerated emissions.
To be fair to Prentice et al. (2001), one should note that the article attempts to apply the allegedly measured decrease in atmospheric ratio of 13C/12C to differentiate fossil fuel CO2 from that emitted by outgassing of the oceans (when the water warms up it releases some of the dissolved CO2 that it absorbed when it was colder), but the conclusion still does not follow: the allegedly measured decrease in the atmospheric ratio of 13C/12C could only indicate that (some of the) increased atmospheric content of CO2 may be due to any increased decomposition of C3-type plant material, of which human combustion of fossil fuels provides only some 10{154653b9ea5f83bbbf00f55de12e21cba2da5b4b158a426ee0e27ae0c1b44117} (and even that only provided that CO2 outgassed from the oceans is predominantly what is absorbed from the atmosphere, and not produced by C3-plants decaying in the water).
There is ample evidence that decay of plant material has indeed increased in the period investigated by Prentice et al. (2001). First of all, the atmospheric concentration of CO2 has risen, certainly in the second half of the twentieth century, and resulting carbon fertilization has enhanced plant growth, thereby producing more C3-type material for decay. Second, temperatures have increased during the last quarter of the twentieth century, and warmth not only enhances plant growth but also intensifies the rate of decay.
If the measurements of a decrease in the 13C/12C ratio cited by Prentice et al. (2001) are indeed correct (I have my doubts: it seems that such a small change could be well within the error margin of the method), the most one could conclude would be that emissions of gasified C3-plant material increased during the last quarter of the twentieth century—but not that this must be due to human combustion of fossil fuels.
Thus, the only conclusion warranted by the articles and measurements cited is actually that temperatures have probably increased during the last quarter of the twentieth century.
This is not news – we all know that temperatures have increased. Consequently, the 13C/12C argument seems to be just another piece of circular or unwarranted IPCC reasoning purporting to demonstrate that “global warming” (a.k.a. “climate change”, a.k.a. “global climate disruption”) is due to human emissions – which this very book so effectively demolishes.
‘Slaying the Sky Dragon: Death of the Greenhouse Gas Theory‘ first published in 2010 by various authors.
Reference:
[1] (www.ipcc.ch)
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