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Climate Skeptic Fool's Gold

Posted on 19 August 2011 by dana1981

Over the past 40 years, global climate models have become dramatically more advanced and complex in their representations of the Earth's climate system.  In the 1970s, when our understanding of the global climate (and our computing power) were still relatively rudimentary, some simple climate models nevertheless yielded global warming predictions which have turned out to be very accurate.  In the 1980s, climate models and computing technology improved, and so did climate scientists' predictions using those models.  Today's climate models are so advanced in their representation of the Earth's complex climate, that they run on some of the world's fastest supercomputers.  As climate models are able to represent the climate more and more accurately, their predictions will continue to improve as well.

Some climate "skeptics" tell us that climate model predictions are worthless because they're just that - models.  It's true that like all models, climate models will never be perfect, but that doesn't mean they can't be useful.  Climate models have already proven that they can make accurate predictions

The reason that even simple climate models nearly four decades ago were able to accurately predict the ensuing global warming was that they're based on physics.  For example, we've known since British physicist John Tyndall's laboratory experiments in 1859 that greenhouse gases like carbon dioxide trap heat.  In 1896, Swedish scientist Svante Arrhenius calculated how much the planet would warm in response to a doubling of the amount of carbon dioxide in the atmosphere, and his estimates were not far off from climate scientists' today.  Because it's based on solid fundamental physics, climate science has aged like a fine wine.

Nevertheless, some scientists distrust the conclusions drawn from modern climate models, and have taken to creating simple models of their own.  The most well-known of these climate model "skeptics" is Roy Spencer from the University of Alabama at Huntsville.  Dr. Spencer has become notorious for frequently using variations of a simple climate model - not too dissimilar from those climate scientists were using in the 1980s - to make wild claims that mainstream climate science is wrong, and man-made global warming is nothing to worry about.

The real problem is that while most climate modelers constrain the possible values of their variables based on physical reality, Dr. Spencer does not.  One example of these variables is the ocean mixed layer (the upper part of the ocean where, due to the wind blowing at the surface and stirring the upper layers, the ocean has about the same temperature and salinity).  Measurements have shown that the ocean mixed layer ranges from about 25 to 200 meters below the ocean surface, and for a model as simple as Dr. Spencer's, the value should be around 100 meters.

However, intead of constraining his variables using physical measurements and then running his model to see if it fits observations, Dr. Spencer just runs his model without limits and tweaks the parameters until it matches the data.  This is a practice known as "curve fitting" or "cooking a graph".  In one instance where he concluded the climate is not sensitive to changes in greenhouse gases, Dr. Spencer's results used a mixed layer depth of 700 meters.  In a recent study in which he concluded that more heat is lost to space than climate models show, amongst numerous other problems, Dr. Spencer's model used a mixed layer depth of 25 meters.  In other cases, Dr. Spencer has used models with as many as 30 fully adjustable, unconstrained parameters.  With so many variables and apparently no desire to match physical reality, Dr. Spencer's model could spit out literally any answer.  As the famous mathematician, John von Neumann said,

"With four parameters I can fit an elephant, and with five I can make him wiggle his trunk."

And as Dr. Barry Bickmore added,

"give me more than 30 parameters, and I can fit a trans-dimensional lizard-goat and make rainbow monkeys shoot out its rear end."

Dr. Spencer is not the only scientist to conduct this sort of curve fitting exercise in recent months.  Two other climate "skeptic" scientists, Craig Loehle and Nicola Scafetta, published a paper arguing that the majority of the global warming over the past 40 years has been caused by the 60-year astronomical cycles of Jupiter and Saturn.  These scientists failed to explain physically how Jupiter and Saturn's orbital cycles could have such a large influence on the Earth's temperature.  Instead, they just tried to see how well they could fit global temperature measurements over the past 150 years using a very simple model with 60-year cycles.

Loehle and Scafetta's model was so simple, in fact, that it only consisted of one short formula that I was able to plug into a spreadsheet and run in about five minutes.  I ran the model backwards in time to see how it would compare to past temperature reconstructions, including one that Loehle himself created in a previous paper.  The 60-year cycle was nowhere to be seen, even in Loehle's own temperature reconstruction, and after a few hundred years, the model diverged dramatically from the data.

L&S failure

Their model is just too simple to accurately re-create global temperature changes, and unlike real climate models (even the simple versions in the 1970s), Loehle and Scafetta's model is not based on physical reality.

Nevertheless, these curve fitting exercises have drawn a lot of attention.  Forbes magazine ran a story on Spencer's study, written by James Taylor of the right-wing think tank Heartland Institute.  The article exaggerated Dr. Spencer's findings, and managed to cram the words "alarmist" and "alarmism" into his eight-paragraph article fifteen times.  Despite Forbes' long history of misrepresenting climate science resesarch, the popular search engine website Yahoo decided to re-publish the biased Forbes article.  Many other media outlets ran stories on Spencer's study.

The other problem is the media's exaggeration of these studies' impacts.  The man-made global warming theory is based on many, many lines of evidence.  It seems as though every "skeptic" paper is touted as the silver bullet which is going to disprove the entire theory.  It's actually very rare for a single study to overturn a scientific theory.  In most cases, when a paper arrives at the opposite conclusion of all other studies in the field, it's because there are fundamental flaws in the paper.  This is quite clearly the case for the Spencer and Loehle & Scafetta papers, and yet predictably, they're being touted as silver bullets by those who don't know any better, but want to believe the man-made global warming theory is wrong.

This is why an independent inquiry found that even the BBC has been giving climate "skeptics" too much air time.  We should certainly pay attention to any good scientific research, but we shouldn't assume that a study's results overturn the body of scientific evidence just because we want it to be true.  How many times must "skeptic" silver bullets turn out to be fool's gold before we stop assuming that they've disproven the robust man-made global warming theory?

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Comments 1 to 27:

  1. This fool's gold comes in so many forms, to the relatively less educated eye that only sees what they want to see, you can just recycle and recycle and the layperson can't tell the difference. It's increasingly not a question of expounding on the science, it's overcoming irrational denial. Though I'm sure this has been discussed before.
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  2. Climate models require a surface energy balance to couple the atmosphere and ocean/land responses--hence a specification of the latent heat transport into the atmosphere due to evaporation is required.This transport is about 80W/m2,as compared to a CO2 radiation flux of about 2 W/m2.Can you present a model for the latent heat transport based on "sound physics", with an associated error bound that is less than 2W/m2? Without such a component model the larger" climate model" cannot claim to be physics based and will be seriously limited in its ability to predict the effect of CO2 on future climate change.
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  3. Could you give a source for your figure of 80 W/m2?
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  4. I am guessing 80 comes from the Trenberth energy budget. On the same diagram, notice that total backradiation is around 333. The CO2 radiation flux is more like 66 (see Schmidt et al, 2010 - the 1.7 (<2) is forcing from pre-industrial levels. However, I am somewhat lost on Anthony Mills question. latent heat transport is of course part of a model, but I am lost as to how this is much affected by anything except temperature and isnt an energy transport off-planet. I think discussion of this belongs in Model are unreliable
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  5. 1998 is still the hottest year in recent times, and this year is shaping up to maintain the lack of warming. It's a bit hard to have confidence in these models when they predict warming, but Earth stubbornly refuses to cooperate. It would be nice if, after 13 years, we actually saw some real warming. Long term, the models might be right, but eventually we need some correlation with current data, if we are to believe them.
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    Moderator Response: [Dikran Marsupial] "It hasn't warmed since 1998" is currently the 9th most popular skeptic canard. Ocassional periods of a decade or so are expected to show little or no warming (or even slight cooling), even in the presence of a long term warming trend (see Easterling and Wehner for details). This happens because natural variability (due to things like ENSO) have a larger magnitude than the expected warming trend due to CO2 radiative forcing, and so the former can temperarily mask the latter. However the variability is quasi-cyclical and so averages out to zero on climate relevant timescales (e.g. 30 years). If you want to defend your analysis, please do so on the "no warming since 1998" thread where it will be on-topic.
  6. rhjames, just to back up the moderator response (and presuming you're not just a robot), please go read Tamino's most recent. You'll find some data where the later values level off in just the way you describe. Problem: it's model-produced data: just a positive linear trend with noise. As Tamino says: "There is absolutely no doubt, none whatsoever, that the actual trend is not only upward, it’s at exactly the same rate throughout, it didn’t stop or slow down or level off. We can be quite certain, because the data were made that way." The point: even in data we know 100% has a positive trend, there will be fluctuations given noise. So: fluctuations in real data doesn't mean there isn't a trend, any more than a chilly April after a warm March means it's winter. Not rocket science.
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  7. I'm actually just trying to find support for the models. This thread seems to be about models, so I thought it appropriate to comment here. My point is that models, once developed, should predict future data. I'm not saying that a short term flattening means that the long term upward trend isn't correct. It seems to me that because of this flattening, it's just too early to claim model compliance, as they are still relatively new, and coincided with the flattening. I see in comment 4 that there is a thread "Models are unreliable", so it's probably best if I try to transfer to that thread to find these answers. Thanks.
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    Moderator Response: [Dikran Marsupial] Read the Easterling and Wehner paper I mentioned in my previous comment. Both the instrumental record and model output show occasional periods of little or no warming even with increasing CO2 radiative forcing. The models do predict that this will happen, they just can't predict when it will happen, because it is a chaotic effect.
  8. Re # 2- I agree that the statement/assertion is itself unintellible. But perhaps the idea is that the CO2 flux is being obtained by difference, rather than by an independent measurement....hence could be a cumulative measurement error. Refering to Trenberth's Energy Balance The heat retention estimate due to not reaching steady state for the level of greenhouse gases is 0.9 w/M2. Since the overall flux is ~341, this seems pretty small vs the naive expectactions of % accuracy on an energy balance this complex...and such eyeballing can lead people astray. Of course the CO2 effect on flux isn't being measured by difference...but rather by the outgoing radiation from TOA and its spectral distribution....if I've got this right.
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  9. rhjames - it's too early to verify model accuracy if you only look at data starting in 1998. But I don't know why you would do that, since we have an instrumental temperature record that spans back into the 19th century, and proxy data long before that. The models are accurate.
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  10. To add to dana's comment, hindcasting (seeing how models reflect past changes) is a way (probably the best way) to test their accuracy. It is testing the model against real data without having to wait for it to happen.... And as dana very clearly showed in this post hindcasting is not employed by Loehle and Scafetta.
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  11. My apologies:an attempt to be brief led to a misleading statement.The"about 2W/m2 "was intended to be an indication of the change in radiation forcing due to observed CO2 increases,and this change is at least an order of magnitude less than the latent heat transport.My comment is a response to dana's statements "Climate models have already proven that they can make accurate predictions" and"Because it is based on solid,fundamental physics,climate science---" Central to computer climate models is the coupling at the air-ocean/land interface through a surface energy balance in which the latent heat component is so much larger than the changes in CO2 radiation forcing under consideration .Can this component be calculated using"solid fundamental" physics with a meaningful error bound? If not ,I doubt whether the models can make satisfactory "predictions" of CO2 effects.
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  12. Mills - yes to questions. You might like to consider how much difference it would make to planetary energy balance if latent component was out was 5%. It will affect the accuracy of predictions about heat distribution, but the energy imbalance remain, ergo, planet continues to heat up. This discussion belongs in "Models are unreliable".
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  13. Anthony Mills, I have put a further comment here
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  14. scaddenp:I appreciate your comments.I simply wish to make the point that"computer climate models" do not use "solid fundamental physics"to describe some important phenomena,and should not be overrated.I took exception to Dana's statement"---climate science has aged like a fine wine" Penfolds Grange it is not! However I would like to see a citation to a latent heat transport model based on fundamental physics that has been used in a computer climate model.
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    Moderator Response: [Dikran Marsupial] Actually climate models do use "solid fundamental physics" (for example fluid dynamics) to describe "some important phenomena" (emphasis mine). The reason they are not 25 year old Laphroig cask strength (not a fan of the grape) is that they don't include all the important phenomena, and because the temporal and spatial resolution is limited by computational expense. As GEP Box said "all models are wrong, but some are useful". Current AOGCMs may not be "Penfolds Grange", but that doesn't mean they are not drinkable, or even quite palatable.
  15. 14, Anthony Mills, Your assumptions about models are just that, and they are very, very, very wrong. You are so far off it's laughable. I encourage you to research things in substantially more depth before making such unsubstantiated claims, while insisting that others prove to you that they are false. You might want to read this: Introduction to Climate Dynamics and Climate Modeling The section that pertains directly to your ridiculous reference to latent heat is here in the chapter/section on heat transport. Want a basic, simple model you can use yourself, that includes latent heat? Try STELLA: Modeling Earth's Climate System with STELLA STELLA II for Mac and PC But really, it took me 75 seconds to find this stuff by googling "latent heat transport climate model". Was it really that hard for a "skeptic" to do the same? As far as a citation... how about Effects of Dynamic Heat Fluxes on Model Climate Sensitivity: Meridional Sensible and Latent Heat Fluxes I just have to say, I am so tired of "skeptics" who "know" everything because they don't bother to actually look for just a couple of minutes.
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  16. Anthony, I might add that if you want to discuss the internals of the climate models, you might prefer to post at where you are talking to the people that build them.
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  17. 15.Sphaerica. Your comments are inappropriate. Please read my comments more carefully before responding. The first line of my comment (2) addresses the "surface energy balance",as does my comment (9). Your references are irrelevant. I suggest you google "surface energy balance"and learn something about the topic. Further,I suggest you study an appropriate textbook on heat and mass transfer to learn about the basic physics needed to describe latent heat transport from a water/air interface. 16.Scaddenp. I guess you are right--thanks.
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  18. 17, Anthony Mills, Enlighten me. What do you know about models and their inadequacies, that I don't? Explain yourself more clearly.
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  19. On 2, 11, 14, 17, Anthony Mills' statements... It's strange how this (emphasis mine):
    Central to computer climate models is the coupling at the air-ocean/land interface through a surface energy balance in which the latent heat component... Can this component be calculated using"solid fundamental" physics with a meaningful error bound? If not ,I doubt whether the models can make satisfactory "predictions" of CO2 effects.
    which is a clear question and evidence of ignorance on the matter, supplemented by a skeptical but utterly foundation-less doubt. This later turned into this confident declaration:
    I simply wish to make the point that"computer climate models" do not use "solid fundamental physics" to describe some important phenomena,and should not be overrated. ... I would like to see a citation to a latent heat transport model based on fundamental physics that has been used in a computer climate model.
    So where did this conclusion come from? What is the evidence for it? Why the sudden change from question to confident knowledge? His response to a response to his vague request for evidence (and isn't it odd how he needs evidence to prove his assumption wrong, but not to make it in the first place?):
    Your comments are inappropriate. Your references are irrelevant. ...learn something about the topic. I suggest you study...
    As if no one can understand the mystical complexities of latent heat but someone who posts four very vaguely worded and utterly unsupported comments on a blog comment thread... comments which do nothing more than utterly without supporting foundation question the validity of the models. And yet, from the original post above:
    Today's climate models are so advanced in their representation of the Earth's complex climate, that they run on some of the world's fastest supercomputers.
    Hmmm. So whom should we trust here?
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  20. Tyndall mayn't have been the first!
    we've known since British physicist John Tyndall's laboratory experiments in 1859 that greenhouse gases like carbon dioxide trap heat
    I chanced upon a delightful wee monograph stipulating that Tyndall was beaten to the punch by three years, by a certain Eunice Foote at "the 1856 AAAS annual meeting in Albany, New York." Though her work wasn't published, it was noted down by a journalist, thus:
    "Prof. Henry then read a paper by Mrs. Eunice Foote, prefacing it with a few words, to the effect that science was of no country and of no sex. The sphere of woman embraces not only the beautiful and the useful, but the true. Mrs. Foote had determined, first, that the action of the rays increases with the density of the air. She has taken two glass cylinders of the same size, containing thermometers. Into one the air was condensed, and from the other air was exhausted. When they were of the same temperature the cylinders were placed side by side in the sun, and the thermometers in the condensed air rose more than twenty degrees higher than those in the rarified air. This effect of rarefaction must contribute to produce the feebleness of heating power in the sun's rays on the summits of lofty mountains. Secondly, the effect of the sun's rays is greater in moist than in dry air. In one cylinder the air was saturated with moisture, in the other dried with chloride of lime; both were placed in the sun, and a difference of about twelve degrees was observed. This high temperature of sunshine in moist air is frequently noticed; for instance, in the intervals between summer showers. The isothermal lines on the earth's surface are doubtless affected by the moisture of the air giving power to the sun, as well as by the temperature of the ocean yielding the moisture. Thirdly, a high effect of the sun's rays is produced in carbonic acid gas. One receiver being filled with carbonic acid, the other with common air, the temperature of the gas in the sun was raised twenty degrees above that of the air. The receiver containing the gas became very sensibly hotter than the other, and was much longer in cooling. An atmosphere of that gas would give to our earth a much higher temperature; and if there once was, as some suppose, a larger proportion of that gas in the air, an increased temperature must have accompanied it, both from the nature of the gas and the increased density of the atmosphere..." May be familiar to some contributors here, but a new one to me. Marvelous bit of history.
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  21. 20, barry, That is so cool! If it's not a hoax it should be brought into the mainstream, with Tyndall and Arrhenius, at ever mention of past climate science.
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  22. The Eunice Foote writeup is very interesting. If accurate it seems like a fairly simple way to demonstrate the greenhouse effect to 'skeptics'. I wouldn't have thought that the extra warming within a glass cylinder would be significant enough to be measured by a thermometer... let alone 20 degrees warmer. Granted, this was apparently a 100% CO2 demonstration, but still an easy way to blow numerous 'skeptic' arguments (e.g. 'the CO2 effect is saturated') completely out of the water.
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  23. Wow, nice find barry! I wonder if Tyndall heard about this piece of work? If this is correct, Eunice Foote certainly deserves to be mentioned as Sphaerica says, a further demonstration of the antiquity of this branch of science. And in its day a major coup for a female scientist.
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  24. I found the pdf on Eunice Foote seventh in the list on a google search, where the terms were the title of John Tyndall's 1859 paper: "Note on the Transmission of Radiant Heat through Gaseous Bodies" I'd be curious to know if other people find the article close to the top, as I did. Suggests it's a popular link, doesn't it? Good news - you HAVE to love google and diligent librarians. I think this is confirmed. Check this link: If you want to backtrace, I got that link from here, which I got from here. First search term was the title of the David Welles digest, "Annual of Scientific Discovery", and it was dead easy to do the rest. I think that has to be legitimate. Agreed?
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  25. 16 decades later I am excited for Eunice Foote. Raymond Sorenson, the author of the monograph, should be congratulated.
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  26. BTW, I emailed Gavin Schmidt suggesting a short feature at realclimate on this footnote in science history. I make the same request here. Ray Sorenson has replied to an email from me laying out a little detail as to how he came across the entry in Annual of Scientific Discovery, and another interesting item regarding a near-simultaneous discovery of the heat absorbing properties of CO2 by another researcher (1863). I've asked for permission to reproduce portions of the email and provided him a link to this thread. I'll update here if he has any issues with this.
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  27. I was all gung-ho for Eunice Foote to get a bit of recognition, but there haven't been many takers. Spencer Weart emailed that he'd include her in his history of science website when he next updates it.
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