What’s wrong with this graph?

A regular here recently offered us this PDF from Willie Soon and Lord Monkton’s Science and Public Policy Institute and asks what is wrong with the graph in there.

i-35688596a9dfb47c970ddb0ca104130d-10yr-CO2-temp-thumb-500x339-48295.jpg

As it happens, Michael Tobis has already taken a look at another very similar construction and identified three deceptions (he kindly called “bugs”) in what is technically correct data.

  1. different smoothing is used on the two types of data. Temperature is presented in monthly mean whereas CO2 looks to have had the seasonal rise and fall removed. This gives the impression of a steady rise in CO2 in stark contrast to the jitters of temperature.
  2. the choice of vertical scale dramatically exaggerates the change in CO2. In the last hundred years, CO2 has risen 100ppm, temperature about .8 oC yet this graph puts the same .8 oC of vertical temperature scale against only 35 ppm of vertical CO2 scale, a factor of three times inflation.
  3. a very short time frame eliminates 90% of the instrumental record and leaves us with much too little temperature data from which to determine a significant trend. Climate is defined as the 30 yr statistics of weather, you can not see a trend in it from 15 years of data.

Michael kindly provides an improved graph with none of those issues.
i-2254861c805aaebcf1845458da14a4d3-40yr-CO2-temp-thumb-500x378-48299.png

40 years of data is enough to discern the signal from the noise, the vertical scale of the graph is fair to both data sets and the smoothing is monthly for both. The lie SPPI is trying to pedal, that CO2 and temperature do not correlate, has vanished along with the emperor’s clothes.

Robert Grumbine has an educational post “Does CO2 over the modern instrumental record correlate with Temperature?” Yes, it does.

82 thoughts on “What’s wrong with this graph?

  1. Obama man,

    You got the wrong website by mistake, suggest you go to whatreallyhappened.com

    Back to reality,

    Firstly to Chris, yes i agree stats can and are used to make ones case look a lot better than it really is. The original intent of the graph was to highlight a rising CO2 whilst temps have stagnated. Coby then used the graph to suggest a denier (me) was trying to pull the wool over everyones eyes. To be honest the scaling issue never crossed my mind as my intent was to merely remind all that temps are still not playing the game.

    Skip,

    Thats OK i understood what you meant, you do raise a good point in that if the temps/weather vary in one day or from one to the next then short term observations may be useless.

    Max,

    Are raising two points here? From a standpoint of CO2 being the major climate driver then we should see (a) seasonal changes in temp as we do in CO2 and (b) a higher temp as CO2 increases.

    I am not sure about (a) i tend to agree with Skip and others on short term stuff (seasonal) but with (b) i do agree which was the whole point of the graph as i said above.

    After reading all above posts (and all were good) is it fair to say that we are indeed measuring/seeing the warming from increased CO2? however can we see any warming from the theoretical +ve feed backs?

    A follow up question to Joseph’s (47), i read a study (cant remember which) where they tried to do GHG experiments and yes lab conditions are not the same as real world. Having said that i seem to recall CO2 to be a stable molecule so maybe not much would change however H20 was a different story as the molecule would react differently under different conditions which of course made it for less predictable in the real world, hopefully someone out there can shed a lot more light (pun intended) on the subject than i.

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  2. @maxwell

    “I’m not sure which ‘claim’ you are referring in this comment. Could you please be more specific? That will help me produce some evidence for it.”

    It’s OK, you go on to give an example in Bell’s theorem.

    Also, if you read my very first comment, I stated in no uncertain terms that I see the correlation between CO2 and global mean temperatures as fact. So I don’t know how one can come to the conclusion I am trying to dismiss this correlation. If it seems I am saying that, I apologize for the confusion. I’m not trying to dismiss the correlation.

    It’s primarily the statement “But I would like to point out that temperature is going to correlate well with any parameter, physical or not, that has increased linearly since the 1950’s.” And others that are similar

    “The question remains, however, how much of an influence [of CO2]?

    That’s the larger point I am making. Correlation in measured data reflects something about reality, while a physical model may or may not reflect something about reality. One must fit the model to data.

    In the case of greenhouse gas (CO2 specifically) forced warming, I think that the data fits the model to a degree that allows to see that there is an influence. Again, the question remains as to what amount of the historical temperature trend is due to increased CO2 concentrations.”

    A question that, in the broad sense remains to be answered. The IPCC has a range of sensitivity estimates, some say the range is set too high, others too low.

    “My problems with the second graph don’t have to do with whether or not there is correlation, but more to do with the fact that the relative scales aren’t present and whoever made the graph did so in a way that makes it seems as though there is a one-to-one relationship between CO2 concentration and global mean temperature, which is not supported by data. Such a quantifiable relationship is still unknown and will likely remain so into the near to mid-future (25 years I say to stick to something).”

    It’s a woodfortrees graph with CO2 offset by -340. I agree that, to some extent, this forms a false impression but the first graph perform the same trick (overlaying the two lines in the same way) and the second graph illustrates the (to me greater) falsehood that is the truncation of the time series. Regarding this quantifiable relationship, the trouble with waiting (say) 25 years to firm up the science before acting will mean, should the higher range of sensitivity estimates apply, that the task will be a huge degree harder than if we act now. Of course if the sensitivity turns out to be at the low end of the estimates then the task will still be much larger in 25 years than it is already.

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  3. crakar:
    “Coby then used the graph to suggest a denier (me) was trying to pull the wool over everyones eyes.”

    Make no mistake here, crakar, I think of you as a victim, not the perptrator.

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  4. Dr. Grumbine,

    thanks for the link and paper. It’s looks like a very interesting analysis. It’ll take me some time to come to grips with the math.

    I do find it interesting that given the import of this paper it was not cited in chapter 9 of the AR4. I would imagine that a paper that finds solar and CO2 forcings accounting for almost 90% of the observed variation in the global mean temperature would appear in the chapter on the ‘detected’ CO2 signal of the most comprehensive report on climate change put together by the scientific community.

    We’ll see what I find on it.

    Thank you though. I want you to know that after recommending Washington and Parkinson, I now have it on my night stand. Thanks for that too.

    Joseph,

    ‘Are you asserting that the normal mode of a CO2 molecule in ‘nature’ is different to what it is in the lab, so its infrared absorption properties would also be different?’

    Umm, no. I am asserting that even though the normal modes of CO2 are the same in the atmosphere as they are in the lab, as well as any other parameter that we can determine in the lab, knowing that information doesn’t really help find the CO2 signal in the historical temperature time series.

    It was that context in which I was discussing experiments versus statistical methods.

    Information on the normal modes or point group of CO2 is important in formulating a simple physical model, which even Arrenhius could do (without quantum mechanics or group theory) over 100 years ago. This information, however, did not make it any easier for him to quantify the influence of CO2 in climate.

    Chris S,

    ‘It’s primarily the statement “But I would like to point out that temperature is going to correlate well with any parameter, physical or not, that has increased linearly since the 1950’s.” And others that are similar.’

    I don’t understand what about this statement invalidates the notion that I think the correlation between temperature and CO2 concentrations is fact. I was pointing out that correlation is meaningful to a certain point.

    ‘Regarding this quantifiable relationship, the trouble with waiting (say) 25 years to firm up the science before acting will mean, should the higher range of sensitivity estimates apply, that the task will be a huge degree harder than if we act now.’

    How are we quantifying the ‘degree’ of difficulty in dealing with human emitted CO2? How is implementing changes to the way we produce energy, transport ourselves and produce goods to maintain our standard of living going to be harder in the future than it already is?

    This is the argument I don’t really understand. You raise concerns over my pointing out specifics about correlations and then basically speculate on what will or will not be easier or harder in future based on totally qualitative measures.

    As I told skippy, when it comes to political action, it becomes a matter of opinion. In my opinion, we don’t need more action than more research and the same slower progress toward more efficient consumption of resources. You might disagree, but that’s simply your opinion. I think it’s hard to make a definitive argument for or against ‘action’ because it just becomes a matter of opinion at some point.

    Cheers.

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  5. Maxwell @55

    The IPCC reports focus on what has been learned since the last report, rather than on a complete survey of everything ever learned. For all that many papers are cited, not all of them are. Not even close. And not even all the papers that I would want to see cited if I were writing a given chapter.

    To take an easy example, the variations in the earth’s orbit are discussed. The oldest paper on the topic that gets cited is Berger, 1978. While that’s now old, the idea (as you can get an idea from the title of Berger, 1988) comes from Milankovitch, 1941. And if you were more interested in the topic, you’d also read Milankovitch’s 1930 and 192x works, and Croll and Adhemar from the 1800s, none of which are cited, but all of which are important in understanding the history of the idea of the influence of orbital variations on climate. Scientists tend not to be historians; I have some leanings that way is all.

    I also was not trying to give you busy work in suggesting that you read the papers that cite Thomson’s 1997 and 1995. It could be that later work has found an error in what he did. I doubt it, but it could have happened.

    I’ll mention too that over at my blog I hang out a post from time to time specifically for questions to be asked. They’re always open. The most recent is February’s ‘Dare to ask a question!’ I don’t always have answers, and sometimes it takes a while to get one when I do. But usually I or a reader can shed some light.

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  6. Dr. Grumbine,

    ‘It could be that later work has found an error in what he did.’

    From what I have read, it seems that researchers now lean more strongly on sulfate aerosols as a component in the historical time series of temperature. In Thomson’s analysis he finds that he can get almost 90% of variation in temperature from just solar and CO2 concentration changes. I think that if there is an error, it is likely in that physical model.

    Also, when GISS put together their overview of climate model simulation results in 2002, internal variability was considered as a ‘source’ for some of the warming. I haven’t thoroughly read that monster of a paper, so I’m not sure how much weight they gave to such internal factors causing warming.

    ‘To take an easy example, the variations in the earth’s orbit are discussed. The oldest paper on the topic that gets cited is Berger, 1978. While that’s now old, the idea (as you can get an idea from the title of Berger, 1988) comes from Milankovitch, 1941. And if you were more interested in the topic, you’d also read Milankovitch’s 1930 and 192x works, and Croll and Adhemar from the 1800s, none of which are cited, but all of which are important in understanding the history of the idea of the influence of orbital variations on climate. Scientists tend not to be historians’

    I think this is not really pertinent to the notion that Thomson’s paper is ‘old’ and therefore not worth citing.

    Milankovitch’s (and I would imagine older work as well) is now part of the standard canon of climate science. I’m sure the important points and contributions that older work made are now in text books that the current generation of climate scientists used in training as students. In many case, I’m sure those text books get cited in place of older work.

    For the same reason, when I write a paper on molecular physics, I’m not going to cite Niels Bohr for the idea of quantized electronic orbitals. If one doesn’t know he contributed that, then they likely won’t get much out of the paper in the first place.

    Thomson’s paper, from just 13 years ago, was in a high profile journal for a conference called ‘Carbon Dioxide and Climate Change’. Not only that, when checking the references, I found a ‘Thompson’ who was cited three times with papers dating back to 1998. That’s just as old as Thomson’s paper.

    Again, I have not read the paper thoroughly so I’m not sure what the issue is. I do know that using measures like times cited, publication merit and institution can be meaningful.
    In the case of climate science, I don’t see why we wouldn’t want to see if the most high profile scientific organization had used a particular publication (especially from as revered a journal as PNAS) to come to their conclusions.

    Thanks for your comments.

    Cheers.

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  7. maxwell and crackar, please review this linked video featuring Dr. Richard Alley entitled “The Biggest Control Knob: Carbon Dioxide in Earth’s Climate History”

    http://www.agu.org/meetings/fm09/lectures/lecture_videos/A23A.shtml

    It will correct several misconceptions the pair of you seem to have.

    By the way maxwell your continued spouting of such spurious term as “point group” and “normal modes” really are showing that you are trying to blind us with pseudo-science when you say (yes I know you later denied it) that CO2 in a lab reacts differently from CO2 in the atmosphere. You get full marks for obfuscation but a zero on your chemistry test since you know (or should know) that they are meaningless in the context which you are trying to use them i.e. effects of IR on atmospheric temperature versus lab measurements. That is obfuscation at its worst since naive people will actually think that you know what you are talking about.

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  8. maxwell says:”If so, I think that’s a rather terrible notion of ‘signal’. From a signal processing perspective, one would expect to be able to pick out the seasonal modulation frequency in the atmospheric CO2 concentration from the overall global average temperature. It’s a well-defined frequency and if CO2 is modeled to have a strong forcing in the overall temperature signal, finding that modulation should not be that difficult. As far as I understand it, however, this has not been done.”

    The anomaly plots removes seasonal variation in temperature, so one most emphatically should not expect to correlate that with seasonal CO2 variation. You could do it, just add the mean monthly temperatures back to the data.

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  9. Umm, no. I am asserting that even though the normal modes of CO2 are the same in the atmosphere as they are in the lab, as well as any other parameter that we can determine in the lab, knowing that information doesn’t really help find the CO2 signal in the historical temperature time series.

    @maxwell: I see what you mean now, but it would be wrong. Knowing the absorption properties of CO2 as observed under controlled conditions is quite helpful. If you only had the instrumental temperature record to go by, and (say) a hypothesized algorithmic relationship between CO2 and equilibrium temperature, you can still come up with a model, but it won’t be as accurate. That’s especially true when you’re considering multiple greenhouse gases, because of the curse of dimensionality.

    Let me try to illustrate with an analogy (although I couldn’t think of any really obvious ones.) Suppose you wanted to model sea level rise as a function of temperature. You can do it by just looking and statistically analyzing instrumental data, but it would be much better if you can start out with some fundamental knowledge about ice melt and thermal expansion derived in the lab under controlled conditions, wouldn’t it?

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  10. t_p_,

    the second graph presented in this post does have the seasonal variation of CO2 concentrations. It was this graph I was discussing.

    Ian,

    ‘You get full marks for obfuscation but a zero on your chemistry test since you know (or should know) that they are meaningless in the context which you are trying to use them i.e. effects of IR on atmospheric temperature versus lab measurements.’

    That comment should be directed at Joseph, not me. He said,

    ‘@maxwell: But you do realize that there are well-designed experiments (and very precise data, actually) showing that CO2 and other greenhouse gases absorb electromagnetic radiation at certain wavelengths but not others, right? This is known since at least the mid 1800s.’

    bringing in the idea that the lab experiments were of importance in this discussion. I merely pointed out that knowing particular molecular parameters like a point group or normal modes do not inform us on how to find the CO2 contribution in the historical temperature time series. In was in the context of the CO2 contribution to the historical temperature time series that I discussing experiments versus statistical manipulation. He took that comment out of context, as you have done, yet again.

    Furthermore,

    ‘By the way maxwell your continued spouting of such spurious term as “point group” and “normal modes”…’

    the point group and normal modes of CO2 are not spurious in the larger context of the greenhouse effect because it is the point group and normal modes (well, a combination of them) that informs us that CO2 absorbs IR light and is a greenhouse gas. Those might be ideas that some others here find interesting or want to look further into. They are interesting to me at least.

    Cheers.

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  11. maxwell said:”t_p_,

    the second graph presented in this post does have the seasonal variation of CO2 concentrations. It was this graph I was discussing.”

    Note that I said temperature anomaly does not include seasonal variations. This is critical to your point “From a signal processing perspective, one would expect to be able to pick out the seasonal modulation frequency in the atmospheric CO2 concentration from the overall global average temperature.”

    In other words, one graph has seasonal variation, the other has it removed. There is absolutely no reason to expect to see the seasonal variation in the temperature anomaly graph. It is trivial to add it back in.

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  12. the point group and normal modes of CO2 are not spurious in the larger context of the greenhouse effect because it is the point group and normal modes (well, a combination of them) that informs us that CO2 absorbs IR light and is a greenhouse gas.

    It is spurious in the sense that there are databases that already tell us what we want to know, i.e. the absorbance of a gas at a given wavelength, temperature & pressure.

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  13. Anyone who has studied chemistry is aware of IR absorption by various molecules. maxwell’s “modes” refer to the different vibrational states which are excited by the specific wave lengths. My hazy memory of this suggests that there are four modes with CO2, however, I seem to remember that only three are IR active (asymmetric stretch, vertical bend and horizontal bend; the symmetric stretch is not IR active).

    This is of course immaterial to temperature increase when LWR is emitted from the surface. When the energy is taken in by the IR active molecules it doesn’t matter which mode is involved. The molecules could be wagging their wings or even giving deniers the finger, what is important is the quantity of energy retained and re-emitted.

    maxwell is doing a great job of muddying the waters with all his grandiose words.

    The bottom line is CO2 is IR active, thus increasing concentrations result in more energy being retained in the atmosphere and thus leading to rising global temperature and climate change.

    Do not get confused by maxwell’s obfuscation, it looks like he may be succeeding, don’t let him.

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  14. Ian,

    ‘maxwell is doing a great job of muddying the waters with all his grandiose words.’

    I don’t understand what the hell you guys are arguing about. It’s like you needed something to argue about and manufactured this.

    Joseph’s original comment to me, in the context of my discussing climate experiments versus statistical manipulations was,

    ‘But you do realize that there are well-designed experiments (and very precise data, actually) showing that CO2 and other greenhouse gases absorb electromagnetic radiation at certain wavelengths but not others, right? This is known since at least the mid 1800s.’

    My response to him in comment #40 was,

    ‘Not only do I realize this fact, I do these types of measurements on a daily basis as well as constructing models that help us predict where we will and will not see changes in the interactions of molecules with electromagnetic fields.

    My experiments, and those of the past, are not that informative, however, when trying to parse out the causal effects of atmospheric CO2 on the climate.’

    Then you said in response to notion of normal modes in particular or molecular physics in general,

    ‘This is of course immaterial to temperature increase when LWR is emitted from the surface. When the energy is taken in by the IR active molecules it doesn’t matter which mode is involved.’

    which was my point the whole time! The information determined in the lab doesn’t really inform our ability to do climate science other than to tell us CO2 is a greenhouse gas. I appreciate you working so hard to make my argument for me. It’s good to have such partnerships in knowledge.

    You guys have a nice weekend.

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  15. maxwell, stop obfuscating. You are just sowing confusion so that your morals can be spread to others. You are a delayer or as Frank calls them, inactivist. You deny that there is a need to do something about AGW.

    Muddying the waters by use of grandiose words and terms may work with some people but it won’t work where contributors have a reasonable knowledge of science.

    All you are doing is using delaying tactics. You continually turn people’s arguments around and try and confuse them. You are just playing with words, not discussing science. You are not a lawyer or politician are you? That is how they behave.

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  16. IAN PATRICK FORESTER GO TO YOUR ROOM!

    (It makes no sense in context but I’ve decided I want to do that from time time.)

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  17. “maxwell is a typical denier throwing confusion about everything all over the place”

    I disagree, Ian. Maxwell’s questioning comes from a place of some knowledge and much curiosity, it seems to me. With so many know-it-alls in these here debates, a genuinely skeptical, inquisitive approach is something to be cherished. I’ve been disappointed to see genuine enquirers alienated by people leaping to conclusions, probably edgy from the frustrations of dealing with true denialists. But I suspect in this case Maxwell isn’t the skittish type.

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  18. Thank you for a very useful website.

    You asked: what is wrong with this graph? I would respond: many things.

    1) The time-series is just too short given between-year variability. Hence Phil Jone’s absolutely correct but widely mis-interpreted comment about what happens when trying to calculate statistically signifant trends using noisy time-series data. You just can’t do it.

    2) The time-series plotted use different smoothing methods based on monthly (temperature) versus smoothed (seasonally detrended) CO2 data. That is inappropriate if one intends to use a common X-axis time scale to overlay two series. Either justify the choice of smoothing methods or just don’t do it at all (e.g., see Krebs 1989).

    3) The choice of left-hand and right-hand Y-axes is arbitrary. Yes, the plots look nice and they fill up the vertical space in such a way as to portray a convincing correlation to untrained eyes. In your words they “are fair to both data sets” and represents what any decent graphics designer would do. I strongly disagree with both you and Michael in this regard. You miss the essential point. One could choose any Y-axis scaling BUT that would not change the essential statistical correlation…the two variables are indeed highly correlated regardless of Y axis scaling.

    4) WoodForTrees.org is a marvelous interactive resource and a useful visualization tool. But seeing more reporting of actual test results might improve the scientific literacy of viewers to this (and other) sites. Many people use Excel, which contains a minimal but useful array of statistical functions that allow calculation of simple Pearson correlations. That and a freely available set of statistical tables (google is your friend) would allow visitors to download raw data, set up a dataset, run a test, and evaluate to their own satisfaction what the results suggest.

    5) In science one generally chooses not to throw away data if they might sometimes later become useful. Choosing a start date of 1979 is fine if you only wish to analyse satellite data. Choosing 1956 might be fine if you only wanted to compare the first quantitative ice measurement data (from the USS Nautilus voyage in 1958) with more modern methods. Choosing HadCrut (from 1880 versus NOAA/GISS data from 1900) also makes a difference depending on what you wish to do. But for your purposes, the Mauna Laua CO2 extend back to 1958, and that should have been the start date for these graphs.

    6) That “correlation does not equal causation” hardly constitutes a “new idea”; it was discussed some time ago by scientists who were demonstrably smarter than me and who therefore preferred arguments based on “the preponderance of evidence” (e.g., Popper 1968).

    “What is wrong with this graph?” is not as useful a question as “what other mechanism might explain recent observed observations on the strength of known physics, chemistry, and biological principles”? Enquiring minds would like to know…

    <<<<<<<<<<<<<<<<<<<<<<<<<<<<<
    Krebs, C.J. 1989. Ecological methodology. HarperCollins (New York, NY). 654 pp.

    Popper, K.R. 1968. The Logic of Scientific Discovery. Second edition. Hutchinson (London). 127 pp.

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  19. Coby,

    I followed your link in post #74, and I nearly fell off my chair laughing!! Thanks for that!

    At the start of the link, there are a couple of follow-on links, one of which is too the interestingly titled “The Climate Scum” website. Here is a direct link to a hilarious post.
    http://theclimatescum.blogspot.com/2010/05/correlation-what-correlation.html

    If you don’t wish to follow the link and have your brain fried by the sheer idiocy of what deniers think, here is a quote for you too all laugh (or cry) at:

    “….This simple graph disproves two of the most egregarious lies of the IPCC cabal: (1) it is getting warmer and (2) the warming is due to CO2. There is clearly no correlation between temperature and CO2! The increase in CO2 is instead caused by the medieval warming period: as we know from the ice cores, CO2 lags 800 years behind temperature…..Using the current CO2 levels as a proxy for past temperatures, we can also conclude that it was about 100 degrees warmer 800 years ago, a period of great prosperity when they built the great cathedrals in Europe, Richard Lionheart (to the right) defeated the islamofascists, Chinese fleets sailed around the Arctic ocean and the Inca and Aztec civilizations were at their peaks. If 100 degrees Kevin was so good for humans 800 years ago, why should we worry about a couple of tens of degrees during the 21st centuries? Only the bedwetting ninnies and nincompoops of the IPCC watermelon (green outside, red inside) fruit sallad could object, because they hate humankind!…”

    So – current warming is caused by the MWP. It was 100 degrees warmer 800 years ago (that’s 100 degrees KEVIN – LMFAO!!!), and we shouldn’t worry about a few tens of degrees of warming!!! And islamic terrorists were a problem even then apparently.

    But of course, as moronic as this sounds, it gets worse. How about this for a quote from “DenialDepot”, one of the other links on the page:
    http://denialdepot.blogspot.com/2009/04/co2-levels-may-have-been-over-2000ppm.html

    “….The scientific consensus is that in 1200AD the climate was excruciatingly hot. Plagues and disease swamped the world and people were dying of heat exhaustion. The situation got so bad that the Vikings moved to a large snow covered island north of Iceland to escape the heat. The ice on this island subsequently melted and so the Vikings called it Greenland. Greenland soon became the wine and farming capital of the world….Didn’t last though. Eventually the climate shifted back again and the Vikings were wiped out by ice….”

    Of course, as they explain, the reason it was so hot in 1200AD was because CO2 levels were 5 times (2,000ppm) what they are today. I’m not sure where the evidence for this comes from, but there you have it folks!!! Proof positive that it is all a fraud – just ask your local village idiot.

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  20. And where do you think i get all my info from Mandas? The villiage idiot knows all like the base hairdresser remember?

    By the way if you are going to pursue a career in comedy you will need to expand your repertoire. He are some ideas you could mull over.

    GW is causing sheep in Scotland to shrink.

    If you are going to make a factual documentary about AGW how do you get your message across without actually revealing any facts? You simply throw in a cartoon and some snippets from a Hollywood disaster movie, the only hard part is keeping a straight face when you accept your award.

    Selling carbon trading to the world is easy but once again the only hard part is keeping a straight face when you collect the cheque(s).

    How do you sell a book about increasing occurrences of cyclones/hurricanes when they have actually been decreasing? You simply put a photoshopped image of about 10 cyclones all over the face of Earth on the front cover.

    Do you think Mann is a big fan of ice hockey or do you think he prefers the more girly version? I think the latter.

    How do you get a photo of a poley bear floating on an ice cube where none exist? Photo shop of course.

    In light of the recent Long Cao study do we now chop down all the trees?

    Supplementary, do you think it would be better if we sprayed the Amazon with Agent orange rather than employ lumber jacks as the aerosols produced by the turbine engines will add to the cooling effect?

    And finally all artifacts that are discovered under retreating glaciers located in areas inhospitable today which show human habitation no more than 1,000 to 2,000 years ago are placed there under clandestine operations and are all part of Lord Monktons global network of climate change denying conspirators. A network whose only concern is to ensure the destruction of the human race by any means possible.

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  21. Barry and t_p_,

    thanks for the vote of confidence. It seems that most of the time, when someone questions the conclusions put forth by Coby here (or others elsewhere), this questioning automatically elicits a defensive response from like-minded contributors.

    This is a very interesting scientific issue for me and I have put quite some time into trying to understand it more thoroughly.

    One question to t_p_, on the issue of seasonal variations in the temperature (or anomaly), if this quantity is supposed to reflect a global mean, why doesn’t the averaging over the surface of the earth get rid of the seasonal variation? That is, why does this variation have to be ‘taken out’? Shouldn’t the averaging over the whole earth get rid of this variation since, on average, there are no seasons?

    Thanks again for your comments.

    Cheers.

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  22. Shouldn’t the averaging over the whole earth get rid of this variation since, on average, there are no seasons?

    That’s an interesting question. I’ll go off on a tangent here, but I’ve looked at the seasonality of the equator in GHCN v2 (using my open source tool – GHCN Processor.) There’s clear temperature seasonality at the equator, with a high in March and April, and a low in July and August. This pattern is sustained for several degrees north of the equator — which is pretty much contrary to what you’d expect for the NH.

    It’s not a huge difference between seasons – maybe one degree Celsius.

    My guess is that it has to do with the Earth’s current eccentricity.

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  23. maxwell, the seasonal cycle in global average temperatures is mostly due to the much greater proportion of land in the NH. The oceans have much more thermal inertia so the greater area of ocean in the south causes a smaller seasonal cycle than in the north. The land area difference is also why CO2 has a seasonal cycle even though the N and S cycles are opposing.

    There is a similar difference for a similar reason in the N and S anamoly, see here for example.

    Interesting about the equatorial pattern though…perhaps is has more to do with rainfall and cloudiness.

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  24. maxwell asked:”One question to t_p_, on the issue of seasonal variations in the temperature (or anomaly), if this quantity is supposed to reflect a global mean, why doesn’t the averaging over the surface of the earth get rid of the seasonal variation? That is, why does this variation have to be ‘taken out’? Shouldn’t the averaging over the whole earth get rid of this variation since, on average, there are no seasons?”

    I did not know until recently that the global mean was not the same for each month. However, it is a fact, and we know what that means for a beautiful sounding idea (seasons average out).

    Have you looked at an advanced undergraduate text, such as Houghton’s Physics of Atmospheres? That is the one I have perused – won’t pretend I have worked the problems, but then again I am not claiming skepticism about its accuracy.

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  25. I pointed this out on Grumbine’s website too.

    A much more appropriate variable to correlate with is e.g. net forcings. And even then you need to invoke a simple atmospheric-ocean model like the 2-box models used by Tamino, Lucia, Nick Stokes and others. In this model, there was a 1-year delay + an e.g. 30 year delay. But you still need to use total forcings not just the CO2 portion.

    There is no expectation of a direct linear correlational relationship between CO2 and GMT. If you play this game long enough, you’ll end up getting burned, because data are model are guaranteed to eventually diverge.

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