What planet is he on?

Could Ian Plimer be right or is he so far from the truth that he is off on another planet somewhere?  [for those who need a Plimer Primer, his ICCC presentation is here, (video, audio coming soon); alternatively check out sympathetic and antagonistic reports of interviews with him]. I wasn’t familiar with his book before the conference and I enjoyed hearing him speak in Chicago: he was entertaining, he made me think and I enthused about what he said (more below). However, I got a blog comment that said:

If you fancy yourself an intellectually honest person, you ought to read http://en.wikipedia.org/wiki/Talk:Ian_Plimer#Volcanoes_.26_CO2_section[Update – this page of WP has now been replaced but a copy is here]

Now I’m used to hearing speculation from scientists at conferences; we often revel in it even when we secretly exchange glances with raised eyebrows and say “X was a bit far-fetched, but interesting if he was right”. Much of what Plimer said was just that – speculation that current estimates of CO2 emissions from volcanic activity are too low. He talked about what we don’t know and currently only estimate. His first bullet point conclusion was:

“Most major sources and sinks of CO2 [are] either ignored or grossly underestimated”

I read the Wikipedia editors’ discussion, for that’s what the link was, and you know what, it really enlightened me to the thinking behind Wikipedia. It also refers to consensus figure from US Geological Survey, which quotes total volcanic emissions of 130-230 million tonnes CO2/y [1], with human emissions coming in at 27 billion t/y. Still, I like to check facts for myself – since I haven’t read Plimer’s book and any research he might cite – is there recent published information that would up the volcanic emissions figure?

Well, I’ve done a bit of searching and a bit of reading.  Most usefully I found a literature review [2] through Skeptical Science; although submitted in 1999/2000 it does provide an overview of a range of values, of which, for global volcanic CO2 flux, the reference used by USGS (Gerlach, 1991) is one of the lowest. The highest estimate is 367 Mt/y. This is based on both terrestrial and submarine volcanoes and includes eruptive and non-eruptive degassing (from craters, fissures and volcanic flanks).  Non-eruptive degassing is generally regarded as underestimated.

Looking for more up-to-date estimates of degassing (not an exhaustive search however), I found a number of interesting references which either corroborate or provide upward estimates of regional degassing.  For example a study in Iceland reported that, while two independent estimates of natural CO2 emissions range between 1 × 108 and 2 × 109 kg year−1, direct CO2 flux measurements from four of the approximately 40 geothermal/volcanic systems in the country amounted to 3 × 108 kg year−1, indicating that these estimates of the total natural flux may be too low [3].  A 2007 study of CO2 degassing from a large area in central Italy also suggests previous underestimation. The total CO2 discharged from the study area was 0.9 × 1011 mol/y (just under 4 Mt/y), about five times higher than a previously published baseline value for terrestrial CO2 emissions [4].

I also found in the literature many instances of newly discovered submarine volcanic activity. One of the most spectacular was reported in June 2008 – a NASA and US National Science Foundation funded expedition explored part of the 1,800-kilometre-long Gakkel Ridge, which cuts across the Arctic from Greenland to Siberia [5]. It is one of least accessible of the planet’s mid-ocean ridges where molten rock rises up from inside the earth creating new crust.

“The scale and magnitude of the explosive activity that we’re seeing here dwarfs anything we’ve seen on other mid-ocean ridges”

said Sohn, [a geophysicist from the Woods Hole Oceanographic Institute] who studies ridges around the world. The volume of gas and lava that appears to have blasted out of the Gakkel volcanoes is “much, much higher” than that seen at other ridges [6].

One reference that Plimer did cite was the ‘discovery’ (and upward estimate) of volcanic seamounts reported in 2007 [7]. University of Cambridge scientists designed a computer programme that was able to analyse the huge amount of data in the sonar lines – some 40 million kilometres of linear profiles from research vessels that have been criss-crossing the oceans since the 1960s. The programme was able to identify volcano-like shapes in the data. They found evidence of 201,055 underwater cones, 10 times more than have been found before, and estimate that in total there could be about 3 million submarine volcanoes, 39,000 of which rise more than 1000 meters over the sea bed.  We still know virtually nothing about the history and activity of most of these.

What about minerals? That was the other major thrust of the presentation – carbonate minerals – and how much of the Earth’s CO2 is locked up in them, produced from a variety of processes:

  • submarine hydrothermal precipitates
  • submarine basaltic alteration (ophiolite formation)
  • igneous carbonate rock (carbonatites) [8]
  • weathering of calcium and magnesium silicates as a sink for atmospheric CO2 [9]

What Professor Plimer was actually saying was that natural geological production of CO2 was currently underestimated and that if we accounted for rates of CO2 production averaged over a more realistic geological time (our recent history being reasonably volcanically inactive) and added these to other natural sources, human CO2 production would pale into insignificance.  So he talked about volcanoes and supervolcanoes and periods when areas such as the Deccan Traps spewed lava and CO2 in truly gargantuan quantities. Yes, we do live in relatively quiet times (fortunately) and major eruptions have been few in the past century, with even Pinatubo only emitting some 42 Mt of carbon dioxide in 1991. But averaged over time – geological time – volcanism is more important to the carbon cycle than current activity suggests.

Yes, a lot of what he said was hyperbole, but it is his opinion; after years of dry academic publications it must be fun to stand up and talk as he does. And you know what – I think Ian Plimer and his speculations are more firmly rooted on this planet that any of the wild forecasts of the IPCC models. But then you probably expected I would say that 😉


  1. Gerlach (1991) Present-day CO2 emissions from volcanoes. Eos, Transactions, American Geophysical Union, 72 (23):249 and 254-255.
  2. Mörner and Etiope (2002) Carbon degassing from the lithosphere. Global and Planetary Change 33:185–203
  3. Ármannsson et al., (2006) CO2 emissions from geothermal power plants and natural geothermal activity in Iceland. Geothermics 34(3):286-296
  4. Frondini et al., (2008) Carbon dioxide degassing from Tuscany and Northern Latium (Italy). Global and Planetary Change. 61(1-2):89-102
  5. Sohn, et. al. (2008) Explosive volcanism on the ultraslow-spreading Gakkel ridge, Arctic Ocean. Nature 453:1236-1238
  6. http://www.canada.com/topics/news/story.html?id=81bb2fd3-63f1-476f-b0be-f48c0dc90304
  7. Hillier and Watts (2007) Global distribution of seamounts from ship-track bathymetry data. Geophys. Res. Lett. 34:L13304
  8. http://www.geology.sdsu.edu/how_volcanoes_work/Unusual%20lava.html
  9. Brady (1991) The effect of silicate weathering on global temperature and atmospheric CO2. J. Geophys. Res. 96:18,101-18,106.
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16 Responses to What planet is he on?

  1. tonyb says:


    In his book Plimer makes claims based on volcano numbers that are not main stream and which he does not attempt to corroborate. I criticised him at the time and think he got the decimal point in the wrong place which wasnt picked up in editing.

    However a few months ago I attended a dinner at Cambridge University and sat next to a volcanologist who told me that very recent research appears to indicate that we have underestimated the number of volcanoes by 10 to 100 times(not 10 to 100%).

    Very many of these were underwater and in polar regions.

    This has implications not only for the volume of Co2 expelled (which I had always understood to be tiny) but also for the potential underwater warming of ice (which I had always understood to be minimal)

    Now it may be that Plimer did get the decimal point wrong in his book OR that he was ahead of the game but didn’t explain himself… What is certain is that our knowledge of volcanoes appears likely to be rewritten in the next few years.


  2. Anonymous says:

    “”If you fancy yourself an intellectually honest person, you ought to read http://en.wikipedia.org/wiki/Talk:Ian_Plimer#Volcanoes_.26_CO2_section“”

    Anyone who says such a thing is a wanker. Doubly so for using Wikipedia as a reference.

    The quality of Wikipedia varies according to the contentiousness of the topic. When it comes to, say SCSI information, it is excellent. When it comes to other subjects, much less so.

  3. VJones says:

    @tonyb, being a relatively recent starter in understanding climate issues I have not investigated much more than the basics outside of the temperature record, since that is my primary interest. I have, however always been interested in volcanoes and geology; I’ve just never taken note of quantities and numbers before, but it has been interesting to do so.

    @anonymous, exactly! The comment and the pages of opinion (at the link) just confirmed my thinking about wikipedia anyway.

  4. tonyb says:


    SteveM used to ban comments on CA when they concerned;

    a) Ernst Beck
    b) Underwater volcanoes melting ice.

    IF Volcanoes are much more common-and more active-than we currently believe, the possibility of them causing some ice melt may need to be revisited. How the co2 from underwater volcanoes contributes to ocean acidification may also need to be re-examined.

    I use the words If and MAY. As good sceptics we need to treat the new information with caution.


  5. VJones says:

    @tonyb, if I ever get to the stage where I have more blog comments than a few per day, perhaps I could have the luxury of a ban policy 😉

    Re volcanoes melting ice – I did not mention that – you did. Any of the references I read about submarine volcanoes at high latitudes said this was unlikely. Gakkel is in 4km depth of water IIRC. And YOU are the Beck fan – not me.

    As for ocean acidicification. Plimer did mention this an felt that seawater buffering was too important. It is an area I’d certainly like to read more on, having scratched the surface of the chemistry a while back.

  6. tonyb says:

    Hi Verity

    Yes, you probably need to run a blog of a certain size before you would want to ban anyone!

    I am not a ‘Beck fan’-I started looking at the history of CO2 measurements- not their accuracy- well before I became fully aware of Beck. I think he has unearthed some interesting data that warrants better auditing. Currently they are routinely dismissed.

    My comment about melting ice was to point out that there appear to be a lot more to volcanoes than we had previously believed. As yet I don’t think any of us know if they have a much greater impact on Co2 and related matters than mainstream science currently asserts.

    A small volcano many kms under the ice is likely to have very little effect on its melting, however many large volcanoes nearer the surface could. I don’t know either way. I’d sure like a big research grant to find out though 🙂


  7. VJones says:

    Hi Tonyb,

    Sorry if my replies to you seemed prickly – I didn’t mean them that way!

  8. While I liked Plimer’s “Heaven and Earth”, his views on volcanoes did not make much of an impression. He has other much more interesting arguments.

  9. KevinUK says:


    For my recent 50th birthday, i was given a book token. yesterday I decided to finally spend it on purchasing some climate books so I went to Waterstones. Under the ‘Science’ section I was somwwhat surprised to see ‘An Inconvenient Truth’. Why wasn’t it in the Fiction section instead?

    Anyway I purchased Plimer’s ‘Heaven and Earth’ and Peter Taylor’s ‘Chill’. I’ve started to read ‘Chill’ and so far it’s a very interesting read as i didn’t realise that such a committed environmentalist like Peter Taylor clearly is and has been could write such a damning (of global warming) book.

    I’m looking forward to reading ‘Heaven and Earth’ soon after I’ve finished ‘Chill’. What did you think of Plimer’s book? Which IYO are the good (convincing) parts and which the not so good parts?

    • gallopingcamel says:

      I was a little surprised by Plimer allowing himself to be sucked into a debate with Monbiot on volcano gas emissions. In my opinion this is one of the weakest points made in “Heaven and Earth”.

      Plimer does a pretty good job pointing out that history (RWP, MWP and LIA) is at variance with the IPCC position. Also with the ice core evidence that shows temperature leading CO2 concentrations in most cases. Also the geological record which shows that polar ice caps are not the norm for this planet.

  10. tonyb says:

    Hi Kevin

    I reviewed Chill for another web site around 6 months ago. Quite a tough read but very interesting. We then had a very long thread on the book in which Peter participated. He is as you say an environmentalist but also a realist and he is somewhat dismayed by the way the science has been hijacked by Ngo’s and Governments.

    If you ever see that he is giving a talk in your neck of the woods he is well worth listening to.


  11. D Bonson says:

    On the wiki article listed above, please note that William “Stoat” Connolley has edited that page 14 times. It may be more productive to actually contact Plimer himself for clarification than refer to an online source that cannot be used for citations in respected organisations.


    “All told, Connolley created or rewrote 5,428 unique Wikipedia articles. His control over Wikipedia was greater still, however, through the role he obtained at Wikipedia as a website administrator, which allowed him to act with virtual impunity. When Connolley didn’t like the subject of a certain article, he removed it — more than 500 articles of various descriptions disappeared at his hand. When he disapproved of the arguments that others were making, he often had them barred — over 2,000 Wikipedia contributors who ran afoul of him found themselves blocked from making further contributions. Acolytes whose writing conformed to Connolley’s global warming views, in contrast, were rewarded with Wikipedia’s blessings. In these ways, Connolley turned Wikipedia into the missionary wing of the global warming movement.”

    • Verity Jones says:

      Thanks for pointing it out but I was aware of his input on this particular one and his stranglehold of info on Wikpedia in general. The point of the blog was quite subtle but was that I like to check my own facts. Actually the comment and what it referred me to made me laugh – I mean “intellectually honest” – WP? Oh LOL!!

  12. Frank White says:

    I wish that Ian Plimer had written the book before I did my master in Earth science. Reading his book, I saw that I missed plenty in the text books we used and not just stuff in climatology.

    Plimer’s book is such a huge and meaty tome that a few typos had to get through. I seem to have mislaid the book so I can’t give the page reference, but I found at least one real blooper and a couple of puzzling statements that arose probably because he rewrote sentences in such a way that the overall meaning seems to be contrary to what he intended. I was going write to him and then forgot.

    In my opinion, people who don’t read much don’t make allowances for typos and misbegotten sentences, so when they do find them they tend to make much ado about it. Plimer has spent at least 50 years in Earth science and has probably forgotten more than I know. So I was not particulary bothered about this big blooper and a couple of doubtfuls because I was confident that some words went adrift.

    I had no problem with his text on vocanoes though or outgassing in general. My supervisor was (and is) a geologist so we got a thorough grounding in plate tectonics, a field that is still full of surprises.

    Plimer is a good read and if you can’t make sense of a couple of sentences here and there just mark the page and move on.

    • Verity Jones says:

      Frank, good to have your perspective. I am not a geologist, but listening to him as a scientist I had no problems with what he said. He was/is trying to make people think differently and, whether they end up agreeing with him or not, that is always a good thing. He may make some errors, but that’s not a problem for me either.

    • KevinUK says:


      I’m on page 165 of Chapter 4 – The Earth at the moment and so have just finished reading about the development of single cell and multi-cellular life on our planet. Fascinating! It’s piqued my interest in this subject so once I’ve finished his book I think I’d do some further research into the subject i..e on the origin of life on our planet.

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