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Plimer’s homework assignment

Filed under: — gavin @ 24 August 2009

Some of you may be aware of George Monbiot’s so-far-unsuccessful attempt to pin down Ian Plimer on his ridiculous compendium of non-science. In response to Monbiot’s request for explanation and sources for some of Plimer’s more bizarre claims, Plimer has responded with a homework assignment that is clearly beyond even his (claimed) prowess. This is quite transparently a device to avoid dealing with Monbiot’s questions and is designed to lead to an argument along the lines of “Monbiot can’t answer these questions and so knows nothing about the science (and by the way, please don’t notice that I can’t cite any sources for my nonsense or even acknowledge that I can’t answer these questions either)”. (Chris Colose and Greenfyre have made similar points). It’s also worth pointing out as Andrew Dodds has done that each question is actually referencing a very well known contrarian and oft-debunked argument, but dressed up in pseudo-scientific complexity.

However, as a service both to Plimer and Monbiot (as well as anyone else interested), we give a quick scorecard on the relevance, actual scientific content (whether the questions can actually be answered) and sources for discussion for each of the, to be charitable, ‘odd’ questions. For relevance, we grade each question on a scale from 0 to 5, 0 being irrelevant to the issue of detection and attribution of 20th Century climate change, 5 being extremely relevant. For scientific content, we rate the reasonableness of the question posed (i.e. does it make any sense at all), from A to F (A being a very well posed question, F making no sense). For sources, we generally point to a paper or discussion that addresses the real issue.

  1. From the distribution of the vines, olives, citrus and grain crops in Europe, UK and Greenland, calculate the temperature in the Roman and Medieval Warmings and the required atmospheric CO2 content at sea level to drive such warmings. What are the errors in your calculation? Reconcile your calculations with at least five atmospheric CO2 proxies. Show all calculations and justify all assumptions.
    • Relevance: 0 – poor. Basic logical fallacy. The existence of prior warm periods that may have been caused by different effects (such as solar changes, orbital variation, continental configuration etc.) does not imply that the human-caused increase in CO2 is not causing warming now.
    • Scientific Content: D – phenology (the distribution and timing of species) can potentially be useful for tracking climate changes, but it is just one of many different types of proxy information available, and has its own regional, temporal, and seasonal limitations. Even more problematic, it is well known that the patterns of surface temperature variability during the “MWP” – more accurately, the Medieval Climate Anomaly (MCA) – and LIA periods were spatially quite heterogeneous, and a record at one or two locations generally tells us very little if anything about global patterns. Even a cursory examination of the relevant recent literature (for instance, Osborn and Briffa, 2006) reveals that the pattern of warmth during the Medieval era was far regional in nature, and does not approach the truly global scale of warmth evident in recent decades.
    • Sources: Greater extent of vineyards today in England than in medieval times. Ice core records. Incoherence of the Medieval warm period.
  2. Tabulate the CO2 exhalation rates over the last 15,000 years from (i) terrestrial and submarine volcanism (including maars, gas vents, geysers and springs) and calc-silicate mineral formation, and (ii) CH4 oxidation to CO2 derived from CH4 exhalation by terrestrial and submarine volcanism, natural hydrocarbon leakage from sediments and sedimentary rocks, methane hydrates, soils, microbiological decay of plant material, arthropods, ruminants and terrestrial methanogenic bacteria to a depth of 4 km. From these data, what is the C12, C13 and C14 content of atmospheric CO2 each thousand years over the last 15,000 years and what are the resultant atmospheric CO2 residence times? All assumptions need to be documented and justified.
    • Relevance: 0 – pure misdirection.
    • Scientific Content: F – We know what CO2 and CH4 levels have been over the last 15,000 years and they oscillated within about 10 ppmv (CO2) and 100 ppbv (CH4) of their Holocene values since the start of the current era – until the industrial period (around 1750) since when CO2 has increased by 35%, and methane concentrations have more than doubled. In each case the values being measured today are way higher than anything measured in 800,000 years of ice core records, and likely higher than anything since the Pliocene (~3 million years ago). The idea that bacterial methane production at 4km in the Earth’s crust has anything to with this is laughable.
    • Sources: IPCC FAQ is all that is required. Do volcanoes produce more CO2 than human activity? Not even close.
  3. From first principles, calculate the effects on atmospheric temperature at sea level by changes in cloudiness of 0.5%, 1% and 2% at 0%, 20%, 40%, 60% and 80% humidity. What changes in cloudiness would have been necessary to drive the Roman Warming, Dark Ages, Medieval Warming and Little Ice Age? Show all calculations and justify all assumptions.
    • Relevance: 3 – clouds certainly have an effect on climate and understanding their variability is the subject of much research.
    • Scientific Content: F – The question makes no sense. Clouds at 0% humidity? Is humidity supposed to be globally uniform? And where should these cloud changes occur? The change for low-level clouds will be of the opposite sign to changes in high level clouds, and changes in the Arctic will give different answers than changes in the tropics. It should go without saying that Plimer is mistakenly assuming that he has accurate information for global temperatures over 2000 years.
    • Sources: Cloud Feedbacks in the Climate System.
  4. Calculate the changes in atmospheric C12 and C13 content of CO2 and CH4 from crack-seal deformation. What is the influence of this source of gases on atmospheric CO2 residence time since 1850? Validate assumptions and show all calculations.
    • Relevance: 0 – completely irrelevant.
    • Scientific Content: F – for those that don’t know ‘crack-seal deformation’ is a geologic process that causes the veins of crystals/minerals etc. in many rock types. (see here). Its relevance to atmospheric concentrations and isotopic composition is absolutely zero. It has no influence on atmospheric residence time – whether since 1850 or at any time in the past.
    • Sources Discussions of the actual carbon cycle and the real influences upon it.
  5. From CO2 proxies, carbonate rock and mineral volumes and stable isotopes, calculate the CO2 forcing of temperature in the Huronian, Neoproterozoic, Ordovician, Permo-Carboniferous and Jurassic ice ages. Why is the “faint Sun paradox” inapplicable to the Phanerozoic ice ages in the light of your calculations? All assumptions must be validated and calculations and sources of information must be shown.
    • Relevance: 0 – (again). The acknowledged climate changes in the past caused by natural events in no way implies that human effects are negligible today. Does the existence of forest fires caused by lightning imply that arson can never happen?
    • Scientific Content: C – There is a lot of interesting science related to deep time, but any discussion of such changes must be prefaced with the acknowledgment that our knowledge of greenhouse gases, temperatures or any other potential forcing or response is very limited compared to what we know about climate today or even in the last ice age. Given that we don’t know precisely what CO2 levels were (let alone CH4, N2O, ozone, aerosols, ice sheet configurations, vegetation distribution etc.), the attributions of climate change at this distance is speculative at best.
    • Sources: The faint young sun paradox.
  6. From ocean current velocity, palaeotemperature and atmosphere measurements of ice cores and stable and radiogenic isotopes of seawater, atmospheric CO2 and fluid inclusions in ice and using atmospheric CO2 residence times of 4, 12, 50 and 400 years, numerically demonstrate that the modern increase in atmospheric CO2 could not derive from the Medieval Warming.
    • Relevance:1 – There are amplifying feedbacks between climate and CO2 – which are most evident in the long ice cores from Antarctica, but this argument is trivial to dismiss without any recourse to ocean current velocities etc.
    • Scientific Content:D – You can calculate the change in CO2 per deg C global warming over long (multi-centennial) timescales from the ice age data – it’s roughly 100ppmv/5ºC = 20 ppmv/ºC. The increase in atmospheric CO2 in the last 200 years is now about 110ppmv, implying that any natural driver would have need to have been more than 5ºC natural warming in recent centuries. This would have been noticed by someone.
    • Sources: None required.
  7. Calculate the changes in the atmospheric transmissivity of radiant energy over the last 2,000 years derived from a variable ingress of stellar, meteoritic and cometary dust, terrestrial dust, terrestrial volcanic aerosols and industrial aerosols. How can your calculations show whether atmospheric temperature changes are related to aerosols? All assumptions must be justified and calculations and sources of information must be shown.
    • Relevance: 4 – aerosols are an important climate forcing, and their history through time (even in the 20th Century) are quite uncertain.
    • Scientific Content: C – Calculating the impacts of aerosols is quite hard, first because we don’t have great records for their distribution through time and space, and secondly there are uncertainties in how the mix with each other and how they interact with clouds. Forcing estimates for the human-caused changes in aerosols over the 20th Century therefore have quite large uncertainties associated with them and are a principle reason why attempts to constrain climate sensitivity from the recent record along have not been very successful. Volcanic effects are however quite well characterised, and actually provide one of the many lines of evidence for why GCM simulations are reasonable since they get the right magnitude and character of the volcanic effects on climate. However, there is no evidence whatsoever for large changes in interstellar dust changes in recent millennia and trying to pin recent warming on that is really grasping at straws.
    • Sources: Climate sensitivity and aerosol forcings.
  8. Calculate 10 Ma time flitches using W/R ratios of 10, 100 and 500 for the heat addition to the oceans, oceanic pH changes and CO2 additions to bottom waters by alteration of sea floor rocks to greenschist and amphibolite facies assemblages, the cooling of new submarine volcanic rocks (including MORBs) and the heat, CO2 and CH4 additions from springs and gas vents since the opening of the Atlantic Ocean. From your calculations, relate the heat balance to global climate over these 10 Ma flitches. What are the errors in your calculations? Show all calculations and discuss the validity of any assumptions made.
    • Relevance: 0 – again more misdirection. The throwing around of irrelevant geologic terms and undefined jargon is simply done in order to appear more knowledgeable than your interlocutor. The argument appears to that climate is changing due to tectonically slow changes the direct heat input from ocean sea floor spreading. This is absurd.
    • Scientific Content: F.
    • Sources: Definition of ‘flitch’.
  9. Calculate the rate of isostatic sinking of the Pacific Ocean floor resulting from post LGM loading by water, the rate of compensatory land level rise, the rate of gravitationally-induced sea level rise and sea level changes from morphological changes to the ocean floor. Numerically reconcile your answer with the post LGM sea level rise, oceanic thermal expansion and coral atoll drilling in the South Pacific Ocean. What are the relative proportions of sea level change derived from your calculations?
    • Relevance: 2 – pretty much irrelevant.
    • Scientific Content: C – isostatic issues in sea level are important on long time scales, and there is still an effect today from the deglaciation 15000 years ago. It contributes a decrease of about 0.3 mm/yr to the global sea level rise, compared to 3 mm/yr total (i.e. about 10%). If the idea was to imply that current sea level rise is simply the response to the deglaciation, then it was completely misleading.
    • Sources: Reconciliation of the sea level rise, thermal expansion and ice melt.
  10. From atmospheric CO2 measurements, stable isotopes, radiogenic Kr and hemispheric transport of volcanic aerosols, calculate the rate of mixing of CO2 between the hemispheres of planet Earth and reconcile this mixing with CO2 solubility, CO2 chemical kinetic data, CO2 stable and cosmogenic isotopes, the natural sequestration rates of CO2 from the atmosphere into plankton, oceans, carbonate sediments and cements, hydrothermal alteration, soils, bacteria and plants for each continent and ocean. All assumptions must be justified and calculations and sources of information must be shown. Calculations may need to be corrected for differences in 12CO2, 13CO2 and 14CO2 kinetic adsorption and/or molecular variations in oceanic dissolution rates.
    • Relevance: 5 – the carbon cycle is actually a key issue.
    • Scientific Content: A – understanding the carbon cycle given multiple constraints on the carbon fluxes (including some of the issues raised in the question) is important in showing that the ~35% rise in CO2 since ~1750 is in fact anthropogenic. This has been shown numerous times to be consistent with the known human emissions, increases in oceans and terrestrial carbon, the decrease in 14C content of the atmosphere, the decrease in 13C content in the atmosphere, the decrease in O2 in the atmosphere.
    • Sources: Read the FAQ.
  11. Calculate from first principles the variability of climate, the warming and cooling rates and global sea level changes from the Bölling to the present and compare and contrast the variability, maximum warming and maximum sea level change rates over this time period to that from 1850 to the present. Using your calculations, how can natural and human-induced changes be differentiated? All assumptions must be justified and calculations and sources of information must be shown.
    • Relevance: 4 – detection and attribution of climate change is an important issue.
    • Scientific Content: B – First principles calculations of climate variability are most closely approximated by GCMs and multiple modelling groups have done various Holocene simulations. Attribution of any climate changes requires model simulations with and without each particular forcing and for the Holocene, this involves changes in the orbit, greenhouse gases, solar, meltwater regimes, ice sheet change, aerosols etc. and a comparison of the signature of the responses with patterns observed in the real world. However, comparable data to 20th Century sea levels or temperature changes are not available going back to the beginning of the Holocene.
    • Sources: Attribution of mid-Holocene hydrologic changes to orbital forcing. Attribution of patterns of cooling at 8.2 kya to drainage of Lake Agassiz. Attribution of pre-industrial variability over the last millennia to solar and volcanic forcing (IPCC Ch8, p680+).
  12. Calculate the volume of particulate and sulphurous aerosols and CO2 and CH4 coeval with the last three major mass extinctions of life. Use the figures derived from these calculations to numerically demonstrate the effects of terrestrial, deep submarine, hot spot and mid ocean ridge volcanism on planktonic and terrestrial life on Earth. What are the errors in your calculations?
    • Relevance: 1 – irrelevant. Has nothing to do with current causes of species extinction nor sources of CO2.
    • Scientific Content: D – insufficient data exist to infer atmospheric composition, nor the sources of any hypothesised fluxes. We think that it is likely that mass extinctions are probably bad for “planktonic and terrestrial life on Earth” with very little error.
    • Sources: This is a good intro to the P/T extinction event which is fascinating even if mostly irrelevant to today.
  13. From the annual average burning of hydrocarbons, lignite, bituminous coal and natural and coal gas, smelting, production of cement, cropping, irrigation and deforestation, use the 25µm, 7µm and 2.5µm wavelengths to calculate the effect that gaseous, liquid and solid H2O have on atmospheric temperature at sea level and at 5 km altitude at latitudes of 20º, 40º, 60º and 80ºS. How does the effect of H2O compare with the effect of CO2 derived from the same sources? All assumptions must be justified and calculations and sources of information must be shown.
    • Relevance: 3 – radiative transfer is a key issue.
    • Scientific Content: F – the question as it stands makes no sense. How can using fossil fuel emissions of CO2 allow you to calculate the impact of total H2O? And why only three wavelengths? You would need the whole atmosphere distribution of water (in all three phases and which doesn’t exist outside a model) in order to calculate the radiative fluxes, and a full GCM to calculate all the other fluxes that influence the temperature. If Plimer is actually alluding to the impact of the direct injection of water vapour into the atmosphere from the combustion of hydrocarbons, then this makes even less sense since the perturbation time for water vapour is measured in days (rather than decades to centuries for CO2) and the relative importance of anthropogenic fluxes is much much less.
    • Sources: Importance of water vapour and clouds compared to CO2 for the total greenhouse effect (roughly, 50%, 25% and 20% once overlaps are apportioned). Complete irrelevance of anthropogenic addition of H2O. Calculation of radiative forcing for anthropogenic CO2.

In summary, the relevance of these questions is extremely low, and even when the basic question deals with an issue that is relevant, the question itself is usually nonsensical and presupposes many assumptions that are certainly not a given (at least in the real world). In fact, for the couple of cases where the scientific content is high, the answer is in contradiction to Plimer’s unstated assumptions. The most obvious use of these questions to support a ‘we don’t know everything, so we must know nothing’ type of argument, which is a classic contrarian trope, and one that is easily dealt with.

These questions have as much to do with a debate on human caused climate change as tribbles have to do with astrobiology. Both are troubling, but for very different reasons.

285 Responses to “Plimer’s homework assignment”

  1. 101
    chris says:

    re #81/#93

    Of course it depends by what you mean by “affect the climate”, dave. If you mean make a significant to global scale surface temperature rise, the anthropogenic enhancement of atmospheric greenhouse gases likely made a very substantial contribution to warming in the period 1800 to mid 20th century.

    The anthropogenic increase in atmospheric CO2 resulted in a rise from around 280 ppm in the late 18th century to around 297 ppm in 1900 to nearly 310 ppm around 1940 [*]

    The total expected anthropogenic global temperature contribution over this full period within a climate sensitivity of 3 oC is easily calculated. It’s 0.44 oC at equilibrium.

    So human emissions could account for most of the temperature increase during the period 1800 to mid-20th century. Of course the anthropogenic contribution was “mixed in” with natural solar and volcanic contributions so one doesn’t expect to observe a simple temporal relationship, any more than we expect to see a simple relationship nowadays.

    [*]D. M. Etheridge et al (1996) “Natural and anthropogenic changes in atmospheric CO2 over the last 1000 years from air in Antarctic ice and firn J. Geophys Res. 101, 4115 -4128.

  2. 102
    Nick Gotts says:

    Mike Strong@91,
    Tell me, do you feel the same way about those who trenchantly defend evolutionary theory against creationism, or get angry when the links between smoking and lung cancer or HIV and AIDS are denied for commercial or political motives? Because these are exact parallels: that AGW is real, and an urgent problem, is agreed by the vast majority of relevant scientific experts. Those claiming the state of the scientific debate is otherwise, do so either for motives of gain – the fossil fuel lobby – or because their political ideology (usually devotion to the “free market”, sometimes a kind of cornucopian Marxism) makes it impossible for them to admit that the problem is real and anthropogenic.

  3. 103
    CM says:

    Jeffrey, Lynn: Sacks declares climate activism a fallacy, tells us to never mind the greenhouse gas concentrations, and then wants us all to be part of developing his vision for a technophobic hunter-gatherer future. Why spend time rescuing glimmers of sanity from this text? Mind you, I am all for a constructive discussion of calamitous impacts, feedbacks and tipping points, explaining why uncertainty is not our friend, and arguing for moving towards a steady-state society with appropriate technologies. The future of which rather depends on us doing something now to keep GHGs down.

    Jeffrey, whatever the relative merits of hysteria and deception, hysteria is unhelpful, doubly so when it plays into the hands of deceivers. Lynn, thanks for the reading tips.

  4. 104
    Mark says:

    “None of you see it do you? The bias? The immediate raising of the hairs on the backs of your necks at the hint of any opinion that disagrees with your ideaology.”

    Or the hackles being raised by a troll who calls it an ideology.

    With the wrong spelling.

    It’s called “trolling” on the internet.

  5. 105
    Jimmy Haigh says:

    I reckon Professor Plimer will publish the answers to all of these questions in a peer-reviewed paper with a comprehensive list of references.

  6. 106
    simon abingdon says:

    #102 Nick Gotts

    “Because these are exact parallels” Exact? When was the link between smoking and cancer established by computer modelling? Read the following and tell me that it doesn’t raise even a small doubt in your mind about GCMs.

    From New Scientist 22 August 2009 p20

    “Clearly, composites are a work in progress. The trouble, says aviation engineer Philip Irving at Cranfield University in the UK, is that computer simulations often differ from reality. ‘Computer models are good at calculating composite displacement and stress levels, but they are not yet good at accurately predicting when they will fail,’ he says.

    But thanks to the Comet’s legacy of exhaustive fail-safe testing, he says, stringent real-world tests are mandatory, ensuring plane designers’ simulations are correct.”

  7. 107
    CM says:

    PS re climate activists and communication: “Positive thinking for a cooler world”, New Scientist’s editorial take on the APA report that Lynn already posted a link to earlier.

  8. 108
    Steve Brown says:

    @91: “…yelling at each other on blogs…discounting the possibility that both sides might be just a little-bit correct.”

    To quote Richard Dawkins: “In an argument with two opposing sides, it is a logical fallacy to assume that the truth lies somewhere in the middle of both arguments. Quite often, one side is simply wrong.”

  9. 109

    Mike Strong (91),

    There’s a fair bit of namecalling in your reponse for a self-professed well mannered individual.

    You seem to discount the possibility -nevermind the evidence- that one side is more wrong than the other.

  10. 110
    mauri pelto says:

    Hey skipper most of the worlds glaciers have not been retreating for 200 years. Almost all are now smaller than 200 years ago, but a majority of glaciers in the Alps and North Cascades advanced from 1950-1975. The widespread rapid retreat is since 1975.
    Global review
    Glacier by glacier review

  11. 111
    tamino says:

    Re: #91 (Mike Strong)

    I’ll tell you what I’m sick of: people who cry “listen to both sides” because they can’t or won’t recognize outright liars. Or do you think Ian Plimer is just expressing an honest difference of opinion?

    You’re trying so hard to keep an open mind that your brain fell out. As for your claim that you have manners, that’s hard to believe when you accuse RealClimate of being the “Rush Limbaugh of AGW supporters.” Shame on you, you hypocrite.

  12. 112
    chris says:

    re #106

    simon, your post is based on a bit of a non-sequiter! Nick didn’t say anything about computer models, and our concerns about the consequences of massive enhancement of greenhouse gas concentrations has got very little to do with computer models. So a reference to a composite modelling article is of close to zero relevance.

    The “exact parallels” refer (if I understand Nick Gott’s point) to a contrived, concerted and well-funded effort by vested interests, at manufacturing uncertainty in the face of rather strong scientific evidence.

    Incidentally Richard Doll’s evidence for a link between smoking and cancer was based on modelling (epidemiological modelling to assess attribution of causal factors) and as such bears a rather strong relationship to the studies of attribution based on current climate modelling. No doubt Professor Doll would have used a computer if he had access to one in the 1950’s!

    In fact the links between global warming and greenhouse gases are rather stronger than the epidemiological links between smoking and lung cancer exisiting then, at least in the early days of assessing causality and probably even through much of the 1970’s, since there wasn’t a good theoretical and empirical basis directing scientists to a causal link. So, for example, the initial expectations were that the causal factors for lung cancer were car fumes or tarmac, and the well-funded liars were able to muddy the waters for so long, because the causality was by no means self-evident.

    We’re in a much stronger position with respect to attribution, since we understand the greenhouse effect rather well, and know that raised levels will cause global warming. We certainly don’t need “computer models” for that.

    So your inference that the link between greenhouse gas enhancement and global warming was “established by computer modelling” is not only simply not true, it’s very silly also!

  13. 113
    Mark says:

    Steve Brown, (108) I’ve said that for AGES.

    Simon asks:
    “When was the link between smoking and cancer established by computer modelling?”

    By statistical modelling. There were people smoking for all their lives and not dying of cancer. This was touted as PROOF that smoking doesn’t cause cancer.

    And from your NS quote (which, by the way, isn’t about climate), your models DO say that the material will break.

    Rather like the climate models: if you put in more and more CO2 eventually you will raise the temperature by 5 degrees Celsius.

    It may not get it *exactly* right. But then that’s why the models and the AGW theory say that the sensitivity of temperature to CO2 is 2.5-4.5C per doubling.

  14. 114

    #91 Mike Strong

    Others have already expressed this more succinctly and in even better, so I almost did not want to reply, but the absurdity of fallacy you present is so strong it begs for correction.

    You have creatively strung together a tremendous number on non sequitur statements and insults about the argument as well as some very strong hypocritical statements in that you contradict yourself in your argument.

    You simply can’t reasonably argue, and sound sane, that you are sick of point counter point and get back to science in this argument when all contexts, are not considered.

    Your comparison of RealClimate to Rush Limbaugh is about as absurd a statement as I have ever witnessed.

    What you don’t seem to recognize is that RealClimate always recognizes when a point may be a little-bit correct… or did you neglect to read the article above (review the grading system Gavin used)?

    You also include yourself in the scientist/engineer category. What is your background, experience, specialty, where have you worked?

    Also, you link goes to a website called

    Does that mean you are starting a new blog where you will present your counter points to other peoples points, and vice versa?

    Might Yoda say: ‘The irony is thick with this one’ too.

    You see, it’s not about bias, it is about science, but science is about learning through the scientific method and that often entails argument, albeit a higher form that one experiences in the world of the political, or the media (the peer review and response process).

    You state:

    Get back to science. Evidence. Fact versus counter-fact. Peer review. Verification.

    But the relevant scientists doing the work have never left, so where does that leave your apparently confused argument? Right smack in the middle of irrelevance and logical fallacy heaven.

  15. 115
    simon abingdon says:

    #112 chris “a non-sequit[u]r!”?

    Nick Gott (#102) said “that AGW is real, and an urgent problem, is agreed by the vast majority of relevant scientific experts”.

    Why? Because the prognoses of computer modelling are believed by the consensus despite the (unavoidable) absence of any real-world verification.

    Boeing would be totally irresponsible if they relied solely on their computer models without the confirmation provided by real-world destructive testing.

  16. 116
    llewelly says:


    But then that’s why the models and the AGW theory say that the sensitivity of temperature to CO2 is 2.5-4.5C per doubling.

    Leaving out ice sheets melting feedbacks and carbon cycle feedbacks.

  17. 117
    J. Bob says:

    #91 Mike, your point was well proven by #111.

  18. 118
    Bagga says:

    Great smack down. Thanks. Plimer totally deserves it.


    Minor grammatical typo in the Relevance section of point 8

    “The argument appears to that climate…”

    presumably should read

    “The argument appears to be that climate…”

  19. 119
    chris says:


    oh well simon. You want to misrepresent Nick’s post and my post and talk about something that neither Nick and I are referring to. Fair enough. But why the pretence of referring to our posts?

    If you want to raise you separate point (which seems to be a notion that the consensus relating to the concerns over massive anthropogenic enhancement of atmospheric greenhouse gas levels is based on “the prognosis of computer models”)..then fine, but I certainly don’t believe that, I doubt Nick Gotts does either (he can tell us!), and neither of us said or implied such a thing.

    Your notion is an odd one to my mind! If it really is your purpose to wrestle the subject away from Nick’s (and my) point to yours, perhaps you can give us some insight on how you arrived at it…

  20. 120
    dhogaza says:

    Boeing would be totally irresponsible if they relied solely on their computer models without the confirmation provided by real-world destructive testing.

    Is this going to become the latest denialist meme? We must verify GCMs by destroying the world we live on?

  21. 121
    tamino says:

    Re: Trolls

    The trolls have shown up on this thread in great numbers. Like many, I have fallen into the trap of “feeding the trolls.”

    Let’s get back to the real topic: Ian Plimer and his book. I repeat from my first comment, that his real purpose with his questions is to avoid answering George Monbiot’s questions. So let’s change our focus to pressuring Plimer to answer what are very straightforward, relevant, and important questions. Like “Where did you get the graph in figure 3 of your book”?

    That’s an extremely simple question. So, Plimer, have you got the guts to answer?

  22. 122
    Rod B says:

    a brief clarification for chris (112): there is a world of difference between epidemiological modelling and physics-based active modelling, so I don’t think your asserted similarities and strong relationships are correct (though you go on in your post to kinda imply such). You’re correct that modelling is not used to prove global warming. But, by itself, that is an insignificant irrelevant statement. The significance of climate change is the degree (amount and timing) of climate change resulting from various levels of input — this derives virtually entirely from GCM models. You not only need the models to assess AGW, they are absolutely critical.

  23. 123
    Bob says:

    RE: Lindzen’s “On the determination of climate feedbacks from ERBE data”

    I have spent too much time in the past few days going over and over Lindzen’s paper. My understanding has some gaps which get better with every reading, but I’m finding some bothersome aspects to it. I’d rather not post my observations here… I’m a layman with an undergraduate training in science, math and modeling, but not a scientist. I don’t think it appropriate to even imply a critique by a person like myself in a forum of this nature (i.e. comments on a blog), especially before the people who’s job it is to do so have done so.

    But I would like some questions answered.

    Is there a real climatologist that would be willing to take a look at a short (1,500 words) analysis, and comment on it?

  24. 124
    Jim Galasyn says:

    Graph of the Day: Annual Inflow to Perth Dams, 1911-2009

    I’d be very interested to hear ideas on this “stepwise” decline in SW Australia rainfall.

  25. 125
    Urs Neu says:

    Re 69 (and also to 175 of the last post on technical issues)
    Klotzbach, Pielke etc. claims about Nocturnal Boundary Layer:

    First open question about these claims is, how measurements at 1.5 m above ground should lead to a warm bias in temperature trends, when warming is stronger at 10m above ground than near the surface? (as found in Lin et al, which they cite as basis). If the warming is smaller at the ground this would mean a cooling bias, I think.

  26. 126
    Nick Gotts says:

    “The significance of climate change is the degree (amount and timing) of climate change resulting from various levels of input — this derives virtually entirely from GCM models.” – Rod B.

    No, it does not – and you have been here long enough to know it. Climate sensitivity to a doubling of GHGs is constrained by evidence from past climates.

    “Because the prognoses of computer modelling are believed by the consensus despite the (unavoidable) absence of any real-world verification.” – simon abingdon

    Simply false – see above. Moreover, the models’ ability to predict response to volcanic eruptions confirms that they are accurate enough to be useful.

  27. 127
    cumfy says:

    Re 9,Some thoughts on Lindzen’s paper

    Lindzen attempts to show that there is a relationship between LW radiative flux anomaly and SST anomaly 20N-20S
    over a 15 year period. Sensitivity (K/(W/m2)) is estimated as the ratio of these properties.

    He also discusses the failure of some AMIP based models to replicate the ERBE observations, which I do not specifically comment on here.

    4 principal criticisms

    1. The analysis is constrained to tropical oceans.
    2. The heat budget for the 20N-20S area is not closed either in i)area or ii)total heat budget (particularly latent heat)

    3. Simply eyeballing the SST and OLR anomaly graphs together does not give a confident impression of a statistically significant relationship between LW flux and temperature anomolies

    4.Analysis is constrained to delta T of >0.2K, which for instance excludes The Pinatubo event which is clearly captured in OLR, ASR with little SST response.

    My main concern is with (2).
    The 20n-20s area of analysis:
    1 Is arbitrarily constrained

    2 Has boundaries across which there are significant oceanic and atmospheric meridional heat flux.
    These flux vary seasonally 2-8PW (equivalent 4-16Wm-2 globally or about 16-64Wm-2 over 20N20S oceans) at both 20N and 20S.
    A 10% interannual variation would be equivalent to about 6-7 Wm-2 over the 20N20S area

    3 Has an unbounded heat budget, particularly in latent heat, which whilst having a relatively uniform mean in the tropics:
    has considerable year to year variability:
    which is typically 5-15 Wm-2, much larger than the OLR variation
    and larger than the 7Wm-2 peak-to-peak OLR anomaly in Lindzen’s paper

    Consequently whilst the temperature variations may be correlated to a greater or lesser extent with radiative flux anomalies (<7Wm-2),they could be wholly or partially caused/explained by interannual variations in

    1 Meridional heat export across 20N and 20S (ocean or atmosphere)(?~6-7 Wm-2)
    2 Latent heat (5-15 Wm-2)

    which, if true, unfortunately renders any subsequent analysis of sensitivity (however well-founded in theory) redundant as the heat budget is not closed.

  28. 128
    Aaron Lewis says:

    Re 54: And wine was drunk for health reasons. Then the question come down to: “Will the grapes make a wine that is strong enough to kill the germs in the drinking water?”

  29. 129
    Edward says:

    Nick #126
    Which GCM predicted what in response to what volcanic eruption? I have been unable to find that information using the search feature on this web site. I thought the measurement of temp after volcanic eruptions was used to tune the the hindcasts of the models.

  30. 130
  31. 131
    Ray Ladbury says:

    Simon Abingdon and Rod B,
    It is incorrect to suggest that everything comes down to the computer models. You can sit down with pen and paper and get a rough estimation of the degree of warming to be expected from a doubling of CO2. Indeed, this is pretty much what Arrhenius did–eventually coming close to the currently favored climate sensitivity of 3 degrees per doubling. Tamino’s two-box model is also pretty straightforward:

    You can get 90% of the way there without a single CPU cycle, and the remaining 10% ain’t gonna rescue you.

    Simon Abingdon says: “Boeing would be totally irresponsible if they relied solely on their computer models without the confirmation provided by real-world destructive testing.”

    Simon, sure you don’t want to think that through again before calling for destructive testing of the planet?

  32. 132
    Craig Allen says:

    Jim Galasyne – Graph of the day – step change in Southwest Western Australian rainfall.

    I suspect that it may be related in part to the Indian Ocean Dipole.

    The most recent step change corresponds to the step change in south-eastern Australian rainfall – see here.

    I’ve seen a plot of estimates of the IOD index going back over a century, but can’t find it just now. The plots I found just now via google don’t go back past that first WA step change.

  33. 133
    Craig Allen says:

    Steven Brown #108 : “To quote Richard Dawkins: ‘In an argument with two opposing sides, it is a logical fallacy to assume that the truth lies somewhere in the middle of both arguments. Quite often, one side is simply wrong.'”

    The problem is that the pseudo-skeptics are a lot better at muddying the water than scientists are at clarifying it. For example, the pseudo-skeptics can point at bogus petitions like the Oregon petition. But where can you see a comparative tally of the opinions of scientists with for example their names and position against their publishing record. The ‘scientific consensus’ is not something that can be quantified and demonstrated to the public. Unfortunately scientists in general are too focussed on their labwork, field work and modelling too be bothered demonstrating a united front.

    I present to you the IPCC website as evidence of this. All that effort, all that expertise, and rather than present it in a manner that is going to have a chance of convincing the average Joe, they just plonk down hulking great reports expecting that it will be accepted as unassailable truth. It has been laughably easy for the denialists to demonize the IPCC because they haven’t even made even a minimalist effort to present their case in a convincing manner. I suspect it has a lot to do with the tendency of many academics to regard the unwashed scientifically illiterate unwashed masses with disdain. RealClimate and other such blogs are great, but they are fringe efforts while the bulk of the scientific community hide in their ivory towers and prattle to each other at their conferences; making important breakthroughs that will be ignored as elections come and go and politicians make momentous decisions that plot a middle course half way between poorly communicated reality and cleverly presented lunacy.

  34. 134

    “. . .where can you see a comparative tally of the opinions of scientists with for example their names and position against their publishing record.”

    Craig, did you miss this survey?

    This is less readily digestible, but closer to what you ask for:

    (I think Ray was the first person I saw link to this.)

  35. 135
    Lou Grinzo says:

    Craig (#132): Bingo! You provided a great summary of the communication gap that’s helping to create a very dangerous situation.

    There are two related issues that I honestly believe not nearly enough people in the reality-enhanced community appreciate:

    1. The deniers are not interested in winning debates, merely sowing enough doubt to delay action. That’s why they argue online so willingly and, some would say, as relentlessly as the Borg on Star Trek: They’re simply putting on a show for the mainstream voters who happen upon the online “debates”. The current situation is like a fight between a pro wrestler and Frasier Crane (from the US TV sitcom). One wants to put on a show and the other comes prepared with facts and expects to have a civil discussion.

    2. We’re at a hideous disadvantage. The other guys get to talk in bumper stickers and tell people things they want to hear (“don’t worry about CO2, it’s all a bunch of foo foo”), while we have to explain at least some of the underlying science to a mainstream that has very few scientists. (Even worse is the “dentist problem” that Michael Tobis has identified, the people with some training in science or a related field who insist on being “independent thinkers” and denying the evidence.)

    For a perfect example, consider Gavin’s and Joshua Wolfe’s book, Climate Change: Picturing the Science. I just finished reading this the other day, and it’s a darn near brilliant example of how scientists should communicate with lay people. (I’ve been a technical writer for about 20 years, and I was impressed to the point that I’ll pay the book the ultimate compliment: I wish I’d written it.) But how many mainstreamers will actually read it? I plan to buy several copies and give them to relatives for Xmas presents, but I’m guessing most will get stuck on a shelf, unread, for “lack of time”. Meanwhile, the other guys get to poke at Al Gore (I love the guy, but talk about an easy target for ridicule!), repeat their tired old nonsense for the 9,000th time, and swarm one web site after another.

  36. 136
    Craig Allen says:


    I note that that was an anonymous survey. I’d like to see scientists start being up front about their opinions.

    I’d like to see a regularly updated website listing all climate related peer reviewed publications and all the scientists who are the authors.

    The papers would ideally have links to at least their abstracts. They would be tagged according to the subcategories of climate science that they address and the list would be filterable by these categories. And they would all have their citation ratings clearly presented.

    A page listing the scientists would similarly be able to be filtered by the subcategories in which they had published papers. And the scientists would be given a credibility rating that is calculated from the quantity and quality (as measured by citations) of their papers.

    All scientists listed would be asked to vote on a set of key questions that are posed in a manner that is understandable by lay people. Plus there would be a place for them to make a statement of their position on the matter.

    If scientists are too timid, busy or lazy to give us their opinion, then we can conclude that those individuals choose to be irrelevant and ignore them.

    Let’s see it laid down on the table for everyone to see. We’ll finally be able to see/prove where the consensus really lies.

  37. 137

    Ray #131:

    Indeed, this is pretty much what Arrhenius did–eventually coming close to the currently favored climate sensitivity of 3 degrees per doubling.

    Actually Arrhenius arrived at 5.8 degrees C per doubling, including the water vapour effect assuming (contrary to current physics-based models where it is an emergent property) constant relative humidity. See pages 14 and 17 for the explanation (he finds 3.4 degrees C for a 1.5x increase).

    A fair comparison would be with the currently estimated 2.0 degrees C for CO2 + H2O only, as he was unequipped to do anything about aerosols, clouds, methane and the rest. So, almost 3x high.

    But hey, this was back in 1896!

  38. 138
    Anne van der Bom says:

    By Fourier analysis of the graviton spectrum, show that the increase in boson emissions in the plasma injector conduit causes a temporal positron anomaly in the dilithium crystal of a magnitude that follows the third Cochran theorem.

    If you don’t know the answer, that proves that I know all about warp drives.

  39. 139
    John says:

    Craig Allen #133 and Lou Grinzo #135

    Excellent posts.

    Some years ago I came across a book that described a novel technique to help you improve your running. “you should lean from the ankles to let gravity pull you forward.” Yes, you read right! “let gravity pull you forward”. I posted that this isn’t possible in a running forum and received some quite aggressive replies, including 1 from a guy that teaches this method. People can see that if you lean forward gravity will make you fall forward and your centre of gravity will indeed have moved forward. An author with ‘qualifications’ in sports science was telling them they can use this to help them run and a coach agreeing with him. What chance did my meagre protestations that a force cannot act perpendicular to its direction really have? The theory seems to make sense and explain what they observe and most importantly gave them hope of an easier solution to running faster. I couldn’t find a way to explain the impossibility of it in the same way.

  40. 140
    Mark says:

    “Leaving out ice sheets melting feedbacks and carbon cycle feedbacks.”

    That’s part of the huge variation.

    I.e. if you assume that there will be no ice sheet albedo change, you will be nearer 2.5C per doubling. This is highly unlikely. If you have easy melting of ice and a large change in albedo (say, for example, the ground underneath is the darkest of the soils), you get nearer the 4.5C per doubling.

  41. 141
    Mark says:

    Simon Says:

    “Why? Because the prognoses of computer modelling are believed by the consensus despite the (unavoidable) absence of any real-world verification.”

    No, because the physics says it will. CO2 impedes IR. If you disagree, please create a non-computer-model model of what the physics says will happen and present it here for review.

    The models say it will cause about 3C per doubling of CO2.

    Observational evidence agrees with that prognosis.

  42. 142
    simon abingdon says:

    #131 Ray

    “Simon, sure you don’t want to think that through again before calling for destructive testing of the planet?”

    Ray, I don’t think it’s the AGW dissenters who are calling for destructive testing: dismantling the world’s economies and starving millions of people should do the job.

  43. 143
    simon abingdon says:

    #137 Martin Vermeer

    “Arrhenius … was unequipped to do anything about aerosols, clouds, methane and the rest. So, almost 3x high”.

    And I wonder by what factor will he be shown to be wrong once we’ve understood the behaviour of clouds (which as we know cover more than 60% of the planet).

  44. 144
    Hugh Laue says:

    We can continue to present the science to those that have not closed their eyes in denial – continue pointing to “start here” on RC, and Weart’s History of climate science. Or the other useful sites demonstrating overwhelming scientific consensus.
    There are the trolls that quickly identify themselves by their wilful stupidity and have no genuine wish to learn. It’s sometimes fun to ridicule them but better to have a standard cut and paste pointer sending them back to where the science can be found.
    The Plimer’s of this world need to be cut off at the root and thanks to RC and the others here who are exposing such fraudulent and un-compassionate behaviour.
    We can also make ourselves heard through organisations such as – they have a climate change petition on the go now.

  45. 145
    Robin Levett says:

    @Aaron lewis #128:

    Re 54: And wine was drunk for health reasons. Then the question come down to: “Will the grapes make a wine that is strong enough to kill the germs in the drinking water?”

    The answer is almost certainly “Not relevant”. It’s the boiling that kills the germs, not the alcohol (although various organic acids found in wine have antiseptic and disinfectant properties).

  46. 146
    Robin Levett says:

    @simon abingdon #143:

    “Arrhenius … was unequipped to do anything about aerosols, clouds, methane and the rest. So, almost 3x high”.

    And I wonder by what factor will he be shown to be wrong once we’ve understood the behaviour of clouds (which as we know cover more than 60% of the planet).

    You are aware that our understanding has moved on since 1896, aren’t you?

    What are in your view the bounds of any cloud effects? Bearing in mind that clouds are both a positive and a negative feedback, depending upon whether it is day or night, or the cloud is high or low, or…?

  47. 147
    stevenc says:

    Kevin I find the Doran survey to be totally inadaquate for getting any sort of feel for where scientists stand on this matter percentage wise. The use of the word significant meaning it can be measured? Can you name any skeptic that I have heard of that wouldn’t have answered yes to this question? I find a much more interesting but still less technical poll then I would like to be the one conducted by S. Robert Lichter and published in 2008 by STATS and conducted by Harris Interactive. They did actually place some numerical values in some of the questions.

  48. 148

    Craig, it sounds wonderful. Are you nominating yourself to do it?

    If so, the second link should be a good start, as the table lists all scientists who have signed activist declarations (mostly concerned about, but a few skeptical of, AGW.)

  49. 149
    Chris says:

    re #142

    What strange notions you have simon. Who said anything about “dismantling the worlds economies”? The imperative based on understanding of the climate system and likely adverse consequences of considerably raised earth surface temperatures is a rational, incremental and progressive move to sustainable energy development. Why would anyone consider “dismantling the worlds economies”? An odd notion!

    Likewise the consequences of unconstrained greenhouse emissions (sea level innundation of coastal areas – the Nile delta, and Bangladesh regions are already suffering and there are large swathes of vulnerable areas), large scale resettlement of populations away from coastal regions, loss of mountain glacier-controlled irrigation (N. India, China, S. America), encroachment of rainfall-depleted regions prgressively towards the higher latitudes, are all expected to have massive effects on the abilities of people to feed themselves. Why would you want to contribute further to these problems? Is that really the aim of your trolling efforts?

    re #143

    The abundant analyses of climate sensitivites are largely empirical/phenomenological, simon and thus incorporate the effects of clouds. So we don’t expect clouds are going to “save us” from the effects of massive enhancement of greenhouse gas levels. Clearly clouds haven’t significantly opposed the rather significant warming of the last century and especially the last 30-odd years. In any case uncertainty obviously applies in both directions – recent evidence indicates that cloud effects may enhance greenhouse-induced warming (positive feedback):

  50. 150

    #142 simon abingdon

    I think it is quite bizarre when people that seem to have a level of cogent capacity that would allow for comprehensive reasoning to not understand that the monetary and a tremendous number of earth economies will be decimated by global warming.

    The only explanation I can think of for individuals such as yourself is ignorance or myopia or some combination of the two. I suppose you could claim naivete, but I doubt you would.

    You just can’t seem to connect all the dots. That does not mean you are wise in saying ‘we don’t know everything’, or ‘models can be wrong’, it simply shows you are unable to connect the dots required to understand what is happening.

    By the way, is, or is not, simon abingdon your real name? I don’t think you ever answered that question, or did I miss something?