Cherry Picking With Tamino

Tamino calls the mid-1970s the start of the “modern global warming period” and reports temperature trends from that date.

http://www.woodfortrees.org/plot/hadcrut3vgl/plot/hadcrut3vgl/trend

Never mind that the long term trend is about one third of the post 1975 trend.

Tamino prefers to measure temperature trends starting just before the positive phase of the PDO began. I can’t imagine why.

Cherries are tastiest when they are bright red.

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52 Responses to Cherry Picking With Tamino

  1. Leon Brozyna says:

    I am reminded of a sci-fi story I read a few decades ago about a planet near the galactic center. Their civilization was puzzled by archeolgical remains which suggested that theirs wasn’t the first highly advanced civilization on the planet. They were also awaiting a rare astronomical event, an eclipse that happens only once every few thousand years. Normally, their sky is always illuminated by the many nearby stars; however, they are looking forward to the pending eclipse. There were some who suspected that there was a connection to the periodicity of eclipses and the regular collapses of civilizations. Suddenly it’s revealed that when their sky becomes dark for the first time in thousands of years and they discover that the universe is much bigger than they suspected, everyone goes mad. Even those scientists who suspected the truth and were prepared, couldn’t stand the truth. And so the cycle is repeated. Reminds me of climate scientists, except they don’t go mad. They just change their tune and start warning of a pending ice age for a generation, til it’s time to change their tune again and start a new generational warning about global warming. And on and on and on …

    • TimC says:

      That was “Nightfall” published Sept 1941 by the great Isaac Asimov. When the sky darkened once every 2050 years the citizens went mad without any light and they burnt the civilisation down as they had no other technology to generate light. (Of course the story would have to start at mid-cycle today to avoid accusations of cherry-picking, and would lose most of its impact.)

  2. Dikran Marsupial says:

    It isn’t cherry picking as Tamino performed an objective test that shows a change point in about 1975. So the data “chooses” 1975, rather than Tamino. If you want to demonstrate that it is a cherry pick, you would need to show that there are other change point detection algorithms that give a different set of change points, and that Tamino chose the algorithm he used to get the result he wanted.

    Now if you disagree about the reason for 1975 being a change point, that is a reasonable argument, but it isn’t a case of cherry picking.

    • Mike M. says:

      This is why you lose the public on the global warming issue. Normal people look at the chart and then look at Tamino’s egghead reply and they “Bullshit!” Just like aerosols and particles are used to explain the cooling that occurred during the prior cool phase of the PDO. Just like when you use worthless proxies to tell us that the consensus that existed for decades about the MWP was wrong.

      The people that believe in the CAGW boogie man WANTED to believe from the first moment they heard of it. It fits their world view perfectly. That’s why they will believe any contorted, twisted, RC approved explanation given to them.

      • Dikran Marsupial says:

        Sadly you are right, “normal” people often do respond to “egghead” stuff (a.k.a. science) by saying “bullshit!” if they don’t like the conclusion (and swallowing it hook line and sinker if they do), even if they have no understanding of the underlying physics. There is a lot of that on both sides of the debate. It does nothing to advance the science or resolve the debate.

      • Dikran Marsupial says:

        BTW, it is also the reason the “warmists” win on influencing policy. The policymakers by and large are of well above average intelligence and are more swayed by rational argument than they are by gut reaction. They are quite capable of understanding the “egghead” stuff, and equally capable of understanding the flaws in the strong conclusions from weak analysis that are so common in the “sceptic” camp.

      • Paul H says:

        No Dikran, policymakers buy into global warming theories for two main reasons -money + power.

      • Philip Finck says:

        Dikran;

        I interact with the government people who make policy, and I sit around the table when the info. is dreamed up that goes up the line to the policy folks (I am ashamed to admit). Let me assure you that said people are not “by and large are of well above average intelligence”. That is utter crap. One must presume that you include yourself in this position of mental superiority? Your comment is not only silly, it is rude and demeaning and only reflects back on your self.

        Its also typical. Anyone who supports AGW is of a mentally and socially elevated position. Anyone who disagrees is a dragging their hand on the ground, smoking, gun toting, retard.

        PS I only use the word `retard’ since it has a historic significance in the nature of the bizarre comment that you made. Having a child with autism I well understand the stigma attached to such a word.

        You really shone a light inside your mask with your statement revealing the true inner mechanisms of your bloated, self important, superior thinking.

        PPS No insult intended to those of of use that own and use firearms in a legal, safe fashion (I’m in that category).

      • Dikran Marsupial says:

        I think if you read my comment you will find I said that attitude was common in both camps (which it is) – “There is a lot of that on both sides of the debate.”. Secondly there are plenty of highly intelligent people who are skeptics, and whom I hold in high regard, such as Roy Spencer and John Christie. So your characterisation of my views is, shall we say, uncharitable (i.e. incorrect).

      • Philip Finck says:

        I am not the one who said, quote, “by and large are of well above average intelligence”. My comments are not `uncharitable, i.e. incorrect. Whether you hold a few scientists in high regard or not, that I cannot determine or comment on.

        That has absolutely nothing to do with your statement re: above. That was what I commented on, and that is what your reply does not address at all and all you did was deflect away from your own statement …since it makes you look pretty bad.

      • Dikran Marsupial says:

        That was a comment on the policymakers, not the “warmist” camp, so I wasn’t complementing the opposition. The policy makers are indeed of above average intelligence, who wouldn’t want their country to be run by the best and brightest brains availablle?

        Both “sceptic” and “warmist” camps have people of average, above average and below average intelligence, and I made no comment on that. I commented on the intelligence of the policymakers, not the lobbyists or activists or general public. That is your misunderstanding.

      • truthsword says:

        Okay Dikran, I have been quite just laughing at most of your posts and shaking my head at the others, but when you say policymakers are above average intelligence, no one… and I mean no one, left, right, or center believes that (outside of said policymakers). That is the single most farcical statement I have heard in climate discussion to date, and that is saying something. You have rendered anything else you have said or will say null by those words.

    • harry says:

      Dickram, why are you such a sad twat?

    • What are you talking about Dikran ? The problem with Tamino’s claim is painfully obvious to anyone with an “open mind.”

      • Dikran Marsupial says:

        Perhaps it is, but it isn’t cherry picking as tamino used a change point algorithm which identifies a change point in the mid seventies. That isn’t cherry picking, just a disagreement between you and him on what caused the change point.

      • truthsword says:

        You must know, Dikran, that you are making youself look just silly by calling “cherry picking” on Steven for something that wasn’t, then turning around and defending for Tamino for something that can certainly be called “cherry picking”.

        At first you try to come across as reasonable and in command of your version of the facts, but you can’t help it, you are doomed to continually shoot yourself in the foot with “policymakers are above intelligence” and “it’s wonderful when Tamino does it and horrible when Steven does it” cherry picking statements.

  3. Brendon says:

    Just to be clear Steve, is this what you are talking about?

    http://tamino.wordpress.com/2010/08/13/changes/

    • I’m talking about the fact that Tamino uses an obviously cherry picked start date, not his lame attempt to justify it with another cherry picked start date.

      Look at the full Had-Crut data series. His cherry picking problem is painfully obvious
      http://www.woodfortrees.org/plot/hadcrut3vgl/plot/hadcrut3vgl/trend

      • Brendon says:

        By “modern global warming period” I assume he means the part where GHG are having the greatest impact?

        I’m more inclined to say the Modern Warming due to GHG emissions is probably the incline from 1950 onwards. But then I only have a small amount of knowledge about the other effects that also affect temp.

        I do know the aerosols and solar activity contribute to the fluctuations in surface temps, but I rely on the climate scientists to recnstruct what impact this has on the planet.

        My efforts would be amaturish by comparison – something I’m all to happy to admit. 😉

    • Philip Finck says:

      HOLD IT! That article says that he visually picked change points. That is beyond beyond belief. This guy is supposed to be a top researcher? Tere are rigorous mathematical methods to determine the `inflection points’ in such a time series. I watched a presentation at a conference recently where a mathematics professor showed the calculations and identified inflection points in the rate of sea level rise in the Halifax, Nova Scotia tide gauge records. He had some great modern inflections and drew many conclusions based on the timing of the inflection points.

      I did not want to insult him in public so I didn’t point out that:

      He used raw data without the appropriate meta data.
      The inflection point was the year when the map datum for the hydrographic charts was corrected, i.e. re-zeroed.
      That with said correction to subsequent data the inflection point disappeared.

      But then I am not one of the “by and large are of well above average intelligence”. 🙂

      • Dikran Marsupial says:

        The initial change points are given by eye, but a determinstitc algorithm was then used, which picked the “inflection points” automatically. If the change points were out, the algorithm would have converged on different values so it isn’t a cherry pick.

        Ultimately it seems to me that the argument is not whether there was a “change point” in about 1975, that much is obvious from just looking at the data. Instead the argument is about what caused the change point, tamino things it is AGW, Steve thinks it may be something to do with ENSO (there is no analysis so at the moment it is just observaion and hypothesis). Incorrectly accusing tamino of cherry picking only obfuscates the substantive issue.

      • I see the change point. It was the PDO shift of 1977.

        His 2.0/century trend is based on using a half PDO cycle – and is completely bogus both mathematically and scientifically.

      • Dikran Marsupial says:

        Sorry Steve, Tamino’s change point algorithm (although rather basic) is quite reasonable. As I said if you disagree about why there is a change point, then make that argument. An unnsuportable accusation of cherry picking, just weakens your argument.

        If you want to show that PDO is responsible for the warming though, you need robust analysis (not just observation and hypothesis) and propose a mechanism that explains not only the correllation but also the strength of the effect. The climatologists have already done this for AGW (maybe not to your satisfaction, but it has been done).

      • “There are None So Blind As Those Who Will Not See”

      • Dikran Marsupial says:

        O.K. Steve, I get the picture, you don’t want to go beyong observation and hypothesis. That may be enough for you to draw conclusions, others require analysis. However I can see that attempts at reasonable discussion have about ended, and you have started with the insults instead, so I’ll leave you to it.

      • “Lies, damned lies, and statistics”

      • Philip Finck says:

        I went back and re-read the above cited document. I couldn’t find any mention of the “determinstitc algorithm was then used, which picked the “inflection points” automatically”.

        Perhaps your right but it doesn’t indicate that in the paper.

        He chose inflection points in a linear trend that is composed of a series of differing slope segments. Then calculated lines of regression on the visually picked segments. Picked intersection points of the various line segments (picked by eye), then calculated slopes and some error estimates.

        Unless there is another paper with more detail, is is (as he said rudamentry(sp) analysis for basing the `modern CAGW warming period. A proper calculus based method for picking inflection points (change points is not the proper terminology), is basic 1st or 2nd year calculus. Or at least that is what I remember from my degree in marine geophysics with a minor in calculus.

      • Dikran Marsupial says:

        It was a rudimentary method, but the point is he used an objective method for chosing the change points so it wasn’t a cherry pick.

        The reason you didn’t find “deterministic algorithm” etc. is because it wasn’t a quote, it was my summary of what he did. Iteratively finding change points by looking for the intersections of straight lines is a perfectly reasonable algorithm, and it is deterministic given the start points.

      • JR says:

        Dikran – Tamino cherry-picked because he blames the trend after 1975 on global warming but he ignored the similar trend from the early 1900s. There’s a change point there too, ya know.

      • Dikran Marsupial says:

        I suspect that he would say the trend in the first half of the 20th century is primarily due to solar forcing (as that is what the IPCC say). However the solar forcing doesn’t explain the warming in the second half of the 20th century. It is possible for the two warming periods to have different causes.

      • JR says:

        Dikran – What you “suspect” and what Tamino “says” are just speculation. As you say yourself above, you need robust analysis (not just observation.

        It is possible for the two warming periods to have different causes. It is also possible that the two warming periods have the same cause. There are also other possibilities…

      • Dikran Marsupial says:

        The IPCC reports already contain the robust analysis of the attribution of both spells of warming. Tamino was merely providing a simplified demonstration/explanation for us laypersons. If you want the robust analyses, download a copy of the report from the IPCC website.

      • JR says:

        Dikran – From the IPCC report: Both detection and attribution rely on observational data and model output.

        If there is a problem with the observations, model output, or both, then there is a problem with the attribution analysis.

      • Dikran Marsupial says:

        Yes of course, which is why the IPCC report explicitly states what the attribution is dependent on so as not to make stronger claims than are supported by the analysis.

        However you can’t pick and choose, if you reject the analysis of the IPCC attribution analysis as there may be a problem with the observations, you wil have to reject Steve’s attribution excercise as well (he doesn’t actually perform any anlysis) as there may be a problem with his observations as well.

      • JR says:

        Dikran – I am not “picking and choosing”. I never said whether or not I accept Steve’s analysis. I was objecting to your claim that Tamino did not cherry pick, when he clearly did.

      • truthsword says:

        Dikran, did you use the words “The IPCC reports already contain the robust analysis”, okay, I’m just gonna let that speak for itself.

      • ChrisD says:

        The IPCC report is largely a synthesis of papers in the peer-reviewed literature. That being the case, it’s not sufficient to simply diss the report. You really have to go back to the papers that it summarized and show where they’re wrong.

  4. glacierman says:

    DM Said:

    “If you want to show that PDO is responsible for the warming though, you need robust analysis (not just observation and hypothesis) and propose a mechanism that explains not only the correllation but also the strength of the effect. The climatologists have already done this for AGW (maybe not to your satisfaction, but it has been done).”

    What robust analysis have the climatologist done to explain how AGW caused a change point in 1975? Climate models? What are the feedbacks used in those models to get the forcing seen? What robust analysis has been done to quantify the feedback mechanisms?

    • Dikran Marsupial says:

      Try reading the IPCC WG1 scientific basis report, it was compiled specifically to give answers to that sort of question. Chapters 8 and 9 are probably the most relevant as they discuss modelling (which is where feed back will be discussed) and attribution.

  5. glacierman says:

    I actually see this assertion by Tamino as a good thing. If he is correct, temps will continue to go up and should accelerate based on feedbacks caused by increased CO2. If they don’t, his hypothesis will be demonstrated to be lacking.

    If the temps are tied to some cycle and he cherry picked the upswing, that will be very obvious in time.

  6. Mike M. says:

    Marsupial: The unwashed masses know enough to band together and throw out the supposedly above average intelligence found in Washington. All of this discussion becomes moot after November 2nd. Then the Alarmists can go back to feeling morally and intellectually superior on obscure internet forums. It’s obvious they didn’t know what to do when handed the reins of power anyway.

  7. glacierman says:

    DM Said:

    “Try reading the IPCC WG1 scientific basis report”.

    That is what I thought you would say.

    I would not consider what you referenced as robust analysis.

    • Dikran Marsupial says:

      Steve has provided no analysis, just observation and hypothesis. Noting a corellation is not an analysis. On that basis, I’ll go with the IPCC (i.e. mainstream science) until Steve provides some credible analysis. I am not against Steve’s hypothesis, it is just that correllations are easy to find, correllations with a plausible mechansim that can explain the required strength of effect is rather more tricky.

  8. Scott says:

    So lets assume Tamino is right and 1975 really does represent some sort of turning point in the whole scheme of things. If so, doesn’t that strongly indicate that CO2 is not the culprit (or at least not the only)? Go pick any good ‘ol CO2 plot and it shows an increase well before 1975. Example:

    http://planetforlife.com/gwarm/glob1000.html

    -Scott

    • ChrisD says:

      If so, doesn’t that strongly indicate that CO2 is not the culprit (or at least not the only)?

      The various clean air laws had really started to be effective by 1975. If, as many climate scientists believe, aerosols were a factor in the cooling that we experienced prior to that date, then the reduction in aerosols would have had the effect of unmasking CO2-influenced warming.

      So, the answer to your question is, “Not necessarily.” There’s a possible explanation for why temps dipped and then started rising, even though CO2 had been steadily going up the whole time–there was a counter-influence that we ameliorated.

      • Scott says:

        I do research in a field related to aerosols (development of aerosol instrumentation actually), and the words “believe” and “possible” are definitely appropriate here. No one really cared about aerosols until the London Smog Episode of 1952 killed people, so no data at all before then other than anecdotal evidence. Aerosol instrumentation wasn’t capable of giving decent aerosol info until about 30 years ago, and many people say the current capabilities of aerosol instrumentation still aren’t acceptable.

        Now I’m not knowledgable on what one would call “aerosol proxies” of past info, but I don’t see how one could make any sort of decent inferences of past aerosol behavior (please let me know if you have suitable references on this). We simply don’t know much about how aerosol composition affects the indirect effect (light scattering) vs. the direct effect (light absorption)…not now, and definitely not in the past. While most of the general community points to “sulfate aerosols” as the important point, the picture is nowhere near that clear.

        And while primary aerosol emissions in the modern world have decreased in the last thirty years, the total change in aerosols is much less clear because natural (biogenic and geogenic) aerosols themselves show huge variability. Additionally, the effect of human emissions on secondary aerosol formation is also a big unknown.

        Basically, to make the conclusion that you’re referencing, one has to assume that natural aerosol effects are essentially constant and the human contribution on top of that (a) was significant, and (b) increase steadily until the mid-70s. From what I’ve seen, the evidence for these two assumptions is no better than the evidence that the majority of observed warming is due to (c) natural oscillations, (d) UHI, or (e) a combination of the two. Basically, to support ‘a’ and ‘b’, the best evidence is in fact the lack of warming in the period and the assumption that there should have been CO2-based warming instead.

        -Scott

  9. Thrasher says:

    Lol. Who is this DM guy who stalks every one of Goddard’s blog posts?

    If you do not understand the ocean cycles and how they play a dramatic effect on global temperatures, then you probably should go read up on them before discussing climate change any further.

  10. Pingback: The Meaning Of ‘Climate Consensus’, In A Single Picture « The Unbearable Nakedness of CLIMATE CHANGE

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