Making up the facts about climate change?

Climate Change Factors

Upton Sinclair said

“It is difficult to get a man to understand something when his salary depends on his not understanding it.”

Let’s just try to understand a fairly straightforward question. I don’t mean straightforward as in ‘easy to determine’ , but as in ‘you’d think it might have a definite, clear answer’. Here it is:

How much carbon dioxide do volcanoes emit?

This seems exactly the kind of question we should be able to answer if we want to be able to say anything serious about climate change (see the top left box of the diagram). It also seems to be the kind of thing that scientific observation and measurement ought to be able to help us with.

Furthermore, it would in principle be perfectly reasonable to conclude that we don’t actually have an answer yet because it’s just too hard to measure volcanoes with existing methods and technology. A little humility never hurt anyone.

So here goes with the answer.

First, the United States Geological Survey claims:

“Human activities release more than 130 times the amount of CO2 emitted by volcanoes.”

Second, Ian Plimer’s book Heaven and Earth states:

“Volcanoes produce more CO2 than the world’s cars and industries combined”. (p. 413)

Since there is a difference of a factor of around 130, it’s reasonable to suppose that these contrasting answers cannot both be correct. Inconveniently, however, the Plimer source does not actually state how much carbon dioxide is produced by volcanoes.

When challenged on this discrepancy in an interview, Ian Plimer did not deny the USGS figures but claimed they were only measuring terrestrial, not oceanic volcanoes: “85% of the world’s volcanoes we neither see nor measure… They leak out huge amounts of carbon dioxide… That does not come into the USGS figures nor does it come into the Intergovernmental Panel on Climate Change’s figures.”

Is this correct? Vulcanologist for the USGC, Dr Terrence Gerlach replied:

“I can confirm to you that the “130 times” figure on the USGS website is an estimate that includes all volcanoes – submarine as well as subaerial … Geoscientists have two methods for estimating the CO2 output of the mid-oceanic ridges. There were estimates for the CO2 output of the mid-oceanic ridges before there were estimates for the global output of subaerial volcanoes.”

The USCG site actually lays out the figures:

“Scientists have calculated that volcanoes emit between about 130-230 million tonnes (145-255 million tons) of CO2 into the atmosphere every year (Gerlach, 1999, 1991). This estimate includes both subaerial and submarine volcanoes, about in equal amounts. Emissions of CO2 by human activities, including fossil fuel burning, cement production, and gas flaring, amount to about 27 billion tonnes per year (30 billion tons) [ ( Marland, et al., 2006) – The reference gives the amount of released carbon (C), rather than CO2, through 2003.]. Human activities release more than 130 times the amount of CO2 emitted by volcanoes–the equivalent of more than 8,000 additional volcanoes like Kilauea (Kilauea emits about 3.3 million tonnes/year)! (Gerlach et. al., 2002)”

Human CO2 emissions relating to energy are also detailed in the EIA Energy Outlook 2009 (using figures from the Energy Annual 2006), with the similar result of 29bn metric tons in 2006.

The IPPC reports tend to refer to radiative forcing (RF) and it is in these terms that they describe the impact on the climate of volcanoes:

“Because of its episodic and transitory nature, it is difficult to give a best estimate for the volcanic RF, unlike the other agents. Neither a best estimate nor a level of scientific understanding was given in the TAR [Third Assesment Report]. For the well-documented case of the explosive 1991 Mt. Pinatubo eruption, there is good scientific understanding.However, the limited knowledge of the RF associated with prior episodic, explosive events indicates a low level of scientific understanding (section2.9, Table 2.11)” (Forster et al.  p. 195)

It seems strange that rather than refer to the low level of scientific understanding about volcanic radiative forcing, which the IPPC report concedes, Plimer would make unreferenced assertions about volcanic emissions of carbon dioxide. He is, after all, a professional geologist. Would such a person not know that scientific claims are supposed to be backed up with data, or references or… anything at all? Would he not also be able to work out that even if terrestrial volcanoes were only 15% of all volcanoes, as he seemed to claim, the total CO2 emissions of these plus the ‘85%’ of volcanoes supposedly not included by Gerlach and the USGS would still amount to nowhere near the amount emitted ‘by the world’s cars and industries combined’?

The volcano issue is just one of many climate change ‘facts’ that are contested by Plimer, and then re-contested by others, including Ian Enting’s fairly detailed critique of Plimer’s book.

So, would a reasonable person be entitled to conclude that Prof Plimer’s figures are organised on the basis of the preconceived desire to deny anthropic climate forcing? This may or may not have something to do with the fact that he is the director of three mining companies – which we might dub the Sinclair effect (remember the salary that depends on not understanding). Or he may have convinced himself on other grounds, such as an entirely novel and undocumented understanding of the carbon dioxide emissions of volcanoes.
He doesn’t seem to think the directorships could influence his opinions in any way, since science is science whoever does it. But it is clear that Plimer’s book has been used to support climate change denial and has bolstered the positions of a number of influential people.

We should scarcely bother with Plimer’s book – after all, it has been said of it:

“It is not “merely” atmospheric scientists that would have to be wrong for Plimer to be right. It would require a rewriting of biology, geology, physics, oceanography, astronomy and statistics”.

The point of this little polemic is to note how even something as seemingly straightforward (though hardly simple) as the amount of carbon dioxide emitted by volcanoes is the subject of contestation.

We don’t primarily argue about the interpretation of facts, as many would like to believe. We argue about the facts themselves.

Even though to me and to others it appears Prof Plimer has failed to give any reference for his assertion that volcanoes produce more CO2 than the world’s cars and industries combined, he still manages to influence the climate change debate by appealing to people who either already agree with his general view, or who aren’t in a position to query his detailed working  (lack of it, that is). It’s interesting that a number of commentators on Plimer’s book have been impressed with the large number of references it contains. Would one more, detailing all those gassy undersea volcanoes no one else knows anything about have been all that hard to provide?


Forster, P., V. Ramaswamy, P. Artaxo, T. Berntsen, R. Betts, D.W. Fahey, J. Haywood, J. Lean, D.C. Lowe, G. Myhre, J. Nganga, R. Prinn, G. Raga, M. Schulz and R. Van Dorland, 2007: Changes in Atmospheric Constituents and in Radiative Forcing. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Gerlach, T.M., 1991, Present-day CO2 emissions from volcanoes: Eos, Transactions, American Geophysical Union, Vol. 72, No. 23, June 4, 1991, pp. 249, and 254-255.

Gerlach, T.M., McGee, K.A., Elias, T., Sutton, A.J., and Doukas, M.P., 2002, Carbon dioxide emission rate of Kilauea Volcano: Implications for primary magma and the summit reservoir, Journal of Geophysical Research, Vol. 107, No. B9, 2189, doi:10.1029/2001JB000407.

Plimer, Ian. 2009 Heaven and Earth. Connor Court Press.


8 thoughts on “Making up the facts about climate change?

  1. Just listened to a commentary with Ian Plimer on ABC from back in October, so thought I’d trawl for further discussion. There wasn’t much in the commentary about the information here, but rather he seemed to be making the argument that: CO2 has been greater and climate warmer in the past with various consequences, not all detrimental to human life; and that climate will and should change.
    It is an important question for the body politic. Communities probably accept that change is inevitable. They are therefore interested in whether they can: resolve the change and re-establish status quo lifestyle, or resolve the disadvantage from the change. Both require adaptive behaviours but the adaptation may be different.
    In the case of anthropogenic waste, regardless of the argument about climate change, and regardless whether it can really be halted or not, I think there is a strong case for policies that encourage communities to become more energy self-sufficient, because this will make communities more resilient to global changes. It seems that only ‘green’ technologies can be built at a community scale. And this is precisely what we need to both stabilise global warming but also to make communities reilient to change from all environmental change throughout the world. With population growth the latter is surely inevitable.

  2. I accept that some people will be motivated by economic interest either deliberately or unconsciously to misrepresent the facts. But that doesn’t explain the willingness of others–particularly members of the general public– to believe them. What does–I think you agree!– is a cultural commitment to individualism that in turn shapes their perceptions of what is in their interest. So we can almost stand Sinclair on his head: it is difficult to get a person to understand that it doesn’t pay (i.e., isn’t in his interest) to believe in some culturally satisfying state of affairs

    1. Agreed – I’ve been thinking about the good people at the Heartland Institute (to pluck one lobby group from the air), who are paid not huge sums of money to defend the interests of oil companies and cigarette manufacturers. The standard criticism of these is that they are cynical manipulators of the facts. I disagree, and would suggest that they (along with all of us) are actually manipulated by opinions sincerely held. Where do these opinions come from? We don’t analyze this as much as we could. The subject of this post, Ian Plimer, may be a director of mining companies, but there are plenty of other mining company directors who don’t feel moved to write books about how climate change is natural.

  3. the usgs is a perfect example of sinclair’s statement because they stand to have long and well paid jobs if the govt can move forward with the dubious and not well supported goal of cutting human emissions greatly to affect earth’s temperature. this article by fourcultures fails to examine the methods used by usgs to get to the data they happily share because it benefits the people working at the usgs and the govt in general. the estimates they use are based on nothing more than very uneducated guesses – they don’t know how many volcanoes there are beneath the sea and they don’t know how active one or more may be 24/7. they can’t accurately measure how much co2 come out of an erupting volcano because a) they don’t have the equipment in place and b)the method of measuring co2 does not preclude other sources of the co2 or even take into account the variables. in short this kind of article is pure nonsense and seeks to discredit one author while ignoring the legion of award winning scientists that are not convinced by the usgs ‘data’. LOL. oh and don’t forget the emails between climate change ‘scientists’ that were divulged and showed intentional falsification of data to further their own jobs.

  4. Your site is long on stats, graphs and complaints about the “conservatives” not believing in this body of work. One of the reactions I see is that well meaning folks such as yourself tend to jam this stuff down other people’s throats. Al Gore did your cause no favors by doing a forecast of the coming doom in his writings lo those many years ago. He got himself extremely rich and nothing he predicted came to pass.
    The thing you should remember is that while you hold your fellow man in contempt he is watching you too. We the people feel the contempt coming from folks like you and you discredit yourself before you have a chance to explain your position. You may want to first humble yourself by calling out the extremists of your groups. Then maybe you can gain some credibility and state your case.

    1. Thanks for reading, Vincent. I hate to discredit myself but I guess I’ll just have to learn to live with it. It’s a while since writing the original post but I think the point was as follows: 1) It is just wrong to claim that volcanoes produce more CO2 than the world’s cars and industries combined, as Ian Plimer did on p.413 of his book, without providing some actual measurements. This is basic science. 2) A more obvious way of criticising the IPCC would have been to point out that they themselves acknowledge that there is a low level of understanding about the ‘radiative forcing’ associated with volcanic activity.

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