More facts against the Mann – ‘late 20th century warming has not been unique within…the past 750 years ‘

Earlier this week, in Facts against the Mann, we noted how some ice core data cast doubt on Michael E. Mann’s recent claim that: 

“overall warmth of the globe and northern hemisphere today is substantially greater than during Medieval time”

This was made in the context of an invective filled rebuttal in the Nevada City, CA Union newspaper, over a column questioning the validity of Mann’s work, citing McIntyre and McKittrick’s work. Sauer wrote:

McIntyre and McKitrick’s work led to a U.S. Senate investigation that debunked Mann’s hockey stick theory that 1998 was the hottest year in the last 1,000. The Senate investigation also found the study of the social networking of the paleoclimatology world showed how close it was and how often a small group of scientists both co-wrote and peer-reviewed papers for each other. In addition, no statisticians were ever involved in their research work or peer review articles.

In response, Mann hauled out the usual tired old hate-filled libel:

Mr. Sauer parroted baseless talking points that have their origin in fossil-fuel industry-funded climate change denial propaganda, not honest scientific discourse.

Source: http://www.theunion.com/opinion/columns/18308425-113/michael-mann-columnist-peddles-discredited-fossil-fuel-industry

Jim McIntosh writes on the WUWT Facebook page:


[A] recent paper suggests tree ring proxies (which underpin Mann’s Hockey Stick Graph that largely kicked off the global warming scare) have underestimated past temperatures, which creates the misimpression that current warming is unique.

esper-2015-tree-ring-compare
Recently published hard science. And bound to never be reported in the media.

” In other words, the new methodology allowed the researchers to capture the low-frequency climatic signals that were systematically eliminated in the MXD data sets. Thus, as a consequence, earlier warm periods during the late 14th and 15th, and 17th centuries “appear warmer” and “have been retained” by this new method, leading the team of six researchers to conclude that “late 20th century warming has not been unique within the context of the past 750 years.”


From the Esper et al. 2015 paper, note that the black line represents the instrumental record. The reconstruction, in red, shows Medieval Warming Period is clearly seen to have temperatures greater than the current modern period. As for the divergence of the instrumental record against the reconstruction, it is important to note that the trees sensing temperature aren’t near human habitation as most of our observing thermometers are, but rather in the Pyrenees mountains.

esper-2015-tree-ring-reconstruction

Here is the paper by Esper. et al. 2015, bold mine.

LONG-TERM SUMMER TEMPERATURE VARIATIONS IN THE PYRENEES FROM DETRENDED STABLE CARBON ISOTOPES

Abstract:

Substantial effort has recently been put into the development of climate reconstructions from tree-ring stable carbon isotopes, though the interpretation of long-term trends retained in such timeseries remains challenging. Here we use detrended δ13C measurements in Pinus uncinata treerings, from the Spanish Pyrenees, to reconstruct decadal variations in summer temperature back to the 13th century. The June-August temperature signal of this reconstruction is attributed using decadally as well as annually resolved, 20th century δ13C data. Results indicate that late 20th century warming has not been unique within the context of the past 750 years. Our reconstruction contains greater amplitude than previous reconstructions derived from traditional tree-ring density data, and describes particularly cool conditions during the late 19th century. Some of these differences, including early warm periods in the 14th and 17th centuries, have been retained via δ13C timeseries detrending — a novel approach in tree-ring stable isotope chronology development. The overall reduced variance in earlier studies points to an underestimation of pre-instrumental summer temperature variability derived
from traditional tree-ring parameters.

Full paper here: https://www.blogs.uni-mainz.de/fb09climatology/files/2012/03/Esper_2015_Geochron.pdf

What I find most interesting is their graph showing how they calibrated the  δ13C data against the instrumental temperature record. While not a perfect match, with R values being rather low, the reconstruction does seem to capture the trend effectively.


esper-2015-tree-ring-calibrationIt seems to me, that δ13C analysis is a better match than tree ring widths by themselves for determining past temperatures, though like anything to do with tree growth, there are many other factors determining growth as outlined in Liebig’s Law of the Minimum. Hence, uncertainty will likely always be large.

[added] I wonder if  Mann’s Bristlecone Pine tree core samples from MBH98 still survive, and what they might say if a δ13C analysis like Esper did was run on them?

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101 thoughts on “More facts against the Mann – ‘late 20th century warming has not been unique within…the past 750 years ‘

  1. This reconstruction is based on one location so it does not represent a fundamental challenge to Mann’s global reconstruction.

    • Mann’s MBH 98 was heavily weighted on one proxy at one location, Sheep Mountain. McIntyre notes:

      Because Graybill’s bristlecone chronologies were so heavily weighted in the Mann reconstruction, demonstrating out-of-sample validity at Sheep Mountain and other key Graybill sites is essential to validating the Mann reconstruction out of sample.

      In the Figure below, I’ve started with the Sheep Mountain chronology as used in Mann et al 1998 (left panel). As CA readers are aware, it has a very dramatic HS-shape and is heavily weighted in the MBH reconstruction. Indeed, without the Graybill bristlecones, the MBH reconstruction is basically noise.

      Source: http://climateaudit.org/2014/12/04/sheep-mountain-update/

      So, “Luke” if Mann heavily weights a proxy in one location to make a global claim, does that make it OK for him, but not for anyone else?

      [note: this comment was edited shortly after posting to fix an error in block quotes formatting -Anthony]

      • I think Anthony should know that Luke haunted Jennifer Marohasy’s site for years. So far he’s been well behaved here, but he gets very upset very quickly.
        The Mann is Luke’s great hero and he especially likes it when fools uses the wrong data for temp reconstruction and use data upside down etc. Luke just loves this kind of deception.

      • Saying one chronology was heavily weighted is not the same as saying it was the only one heavily weighted. The new paper does not in itself refute MBH 98 or any of the many of papers showing the recent warming is unique for hundreds of years. The new paper certainly makes no such claim. It would be useful to see someone include this data in a global reconstruction to see if it has a significant impact.

      • Andy wrote: “if Mann heavily weights a proxy in one location to make a global claim, does that make it OK for him, but not for anyone else?”

        Neither YOU nor Mann should be using a proxy from one location (or overweighted at one location) to draw conclusions about hemispheric or global temperature. M&M and others proved a decade ago that the methodology in Mann’s original Hockey Sticks was badly flawed.

        McShane and Wyner and the debate they prompted indicates to me that the published confidence interval around all published reconstructions depends on the statistical model applied and probably are too narrow.

        Esper (2015) is important because it shows that dC13 data produces a different reconstruction that retains more variability than reconstructions using TRW or MXD measurements at the same site.

      • Paul,

        I studied H. H. Lamb long, long ago and by doing so knew that the CO2 scare was horse feathers from the get-go. It is a crying shame that they have turned the CRU that he founded into the citadel of falsehoods that it is now. A crying shame.

    • Luke:

      You say

      This reconstruction is based on one location so it does not represent a fundamental challenge to Mann’s global reconstruction.

      Even Mann did not say his fr@udulent reconstruction was “global”: he claimed it was only for the Northern Hemisphere.

      If you desire to defend the indefensible then you could at least try to know what you are trying to defend.

      Richard

      • Richard

        “…[D]efend[ing] the indefensible then you could at least try to know what you are trying to defend.”

        LOL. Good point, but I think the warmest horse is out of the barn on that one.

      • @Richards “Even Mann did not say his fr@udulent reconstruction was “global”: he claimed it was only for the Northern Hemisphere.”
        That’s not my understanding. After the HS was broken others were saying the MWP was only a Northern Hemisphere thing. not world wide. correct me if I’m wrong.

      • old construction worker:

        You write:
        blockquote>@Richards “Even Mann did not say his fr@udulent reconstruction was “global”: he claimed it was only for the Northern Hemisphere.”
        That’s not my understanding. After the HS was broken others were saying the MWP was only a Northern Hemisphere thing. not world wide. correct me if I’m wrong.<
        I write to correct you.

        The pertinent paper is
        Mann ME, Bradley RS & Hughes MK, ‘Global-scale temperature patterns and climate forcing over the past six centuries’, Nature, v.392, 23 April 1998
        and it can be read here.

        The paper’s title says it addresses “Global-scale temperature patterns and climate forcing” and this does imply that the paper provides global scale reconstructions, but the paper’s contents provide northern hemisphere (NH) reconstructions and mentions some asserted global effects.

        Its Abstract says

        Spatially resolved global reconstructions of annual surface temperature patterns over the past six centuries are based on the multivariate calibration of widely distributed high-resolution proxy climate indicators. Time-dependent correlations of the reconstructions with time-series records representing changes in greenhouse-gas concentrations, solar irradiance, and volcanic aerosols suggest that each of these factors has contributed to the climate variability of the past 400 years, with greenhouse gases emerging as the dominant forcing during the twentieth century. Northern Hemisphere mean annual temperatures for three of the past eight years are warmer than any other year since (at least) AD 1400.

        The first sentence of the Abstract implies that the reconstructions in the paper are “Spatially resolved global reconstructions of annual surface temperature patterns over the past six centuries” but those plots are NOT the so-called ‘hockey stick’ which – as the final sentence in the Abstracts says – is of “Northern Hemisphere mean annual temperatures”.

        The (possibly deliberate) ambiguity about geographical extent of the temperature reconstructions is also in the body of the paper, for example, this

        The long-term trends in the reconstructed annual mean NH series (Fig. 5b) are quite similar to those of decadal Northern Hemisphere summer temperature reconstructions, showing pronounced cold periods during the mid-seventeenth and nineteenth centuries, and somewhat warmer intervals during the mid-sixteenth and late eighteenth centuries, with almost all years before the twentieth century well below the twentieth-century climatological mean. Taking into account the uncertainties in our NH reconstruction (see Methods), it appears that the years 1990, 1995 and now 1997 (this value recently calculated and not shown) each show anomalies that are greater than any other year back to 1400 at 3 standard errors, or roughly a 99.7% level of certainty. We note that hemispheric mean values are not associated with globally or hemispherically uniform trends. An example of the global pattern for an historically documented35 ‘‘very strong’’ El Nin˜o year (1791) is shown in Fig. 6 top panel, demonstrating the classic warm eastern tropical Pacific and cold central North Pacific sea surface temperature patterns. Analysis of ENSO variability in these reconstructions is discussed in more detail elsewhere.

        The sentence saying
        “We note that hemispheric mean values are not associated with globally or hemispherically uniform trends.”
        is hidden in the paragraph I here quote.

        Clearly, the temperature reconstruction known as the ‘hockey stick’ is for the NH but the paper implies its reconstructions are global. Competent peer review would have demanded that this ambiguity be clarified.

        I hope this answer is sufficient.

        Richard

    • Good point. There are no references to any of Mann’s papers in this paper. The paper does not even contain the word “global”.

    • When you get time from your skywalks get, go to Steve Mc webs site and find the small number, as in a handful of tree that contributed to Mann-rection

    • Felix, it would help if you actually understood the concepts you were trying to defend.
      The issue was the claim that it is invalid to use one proxy to represent the entire world.
      As has been pointed out, for several time periods, Mann’s paper did just that.

      As to being the warmest for the last couple of hundred years, so what. It’s warmer than it was at the bottom of the little ice age. Most people would consider that to be a good thing.

  2. “I wonder if Mann’s Bristlecone Pine tree core samples from MBH98 still survive, and what they might say if a δ13C analysis like Esper did was run on them?”

    Is that a wood chipper I hear starting up?

  3. Dear Dr. Mann;
    If you should happen to see this, please note how Esper et al. changed colors on their graph when they changed datasets; a much more elegant and forthright method than the one you used.

    Have a good day Sir, from one of the persons you banned from your facebook page

  4. The oceans2k results say we’re far from anomalously warm. Seems that Mann’s results contradict them…yet both are used to portray that man has has a large fingerprint in creating unnatural warming.

  5. Since the Holocene Optimum 8000 years ago the earth has been in a gradual overall cooling trend which has continued up to today punctuated by spikes of warmth such as the Roman ,Medieval and Modern warm periods.

    The main drives of this are Milankovitch Cycles which were more favorable for warmer conditions 8000 years ago in contrast to today , with prolonged periods of active and minimum solar activity superimposed upon this slow gradual cooling trend giving the spikes of warmth I referred to in the above and also periods of cold such as the Little Ice Age.

    Further refinement to the climate coming from ENSO, volcanic activity , the phase of the PDO/AMO but these are temporary earth intrinsic climatic factors superimposed upon the general broader climatic trend.

    All the warming the article refers to which has happened since the end of the Little Ice Age, is just a spike of relative warmth within the still overall cooling trend due to the big pick up in solar activity from the period 1840-2005 versus the period 1275-1840.

    Post 2005 solar activity has returned to minimum conditions and I suspect the overall cooling global temperature trend which as been in progress for the past 8000 years ago will exert itself once again.

    We will be finding this out in the near future due to the prolonged minimum solar activity that is now in progress post 2005.

    • The continued reluctance of consensus climate science to properly place current global temperatures within the context of the entire Holocene and the single-minded concentration upon climate models which predict (with little hard evidence) a complete reversal in a matter of years the natural decline in global temperatures which has taken place over many thousands of years is a betrayal of the scientific method and of the people who depend upon science to reliably inform them about the world in which they live.

  6. Conclusions

    “As a consequence, earlier warm periods
    during the late 14th and 15th centuries appear warmer,
    though not statistically significant, compared to the late
    20th century.
    A major constraint of the new reconstruction is the
    substantial difference in recent temperature trends caused
    by post-1850 δ13C correction procedures. The correction
    applied here, accounting for atmospheric 13C/12C ratio
    and plant physiological effects, appeared most suitable as
    it produced a timeseries without any trend in residuals
    after regressing against instrumental temperatures. However,
    developing objective criteria for post-1850 correction,
    independent of the goodness of fit with instrumental
    target data, are needed to establish δ13C based reconstructions
    as an additional proxy for studying climate variations
    over past millennia.”

    read the section on the “correction” process..

    ahem… adjusting raw data again…

    • –ahem… adjusting raw data again…–

      Does this have anything to do with adjusting raw data.
      One gets say pictures of say Pluto from raw data; which are processed to make images.
      Altering the raw data, rather than a copy of the raw data, would be wrong

      • gbaikie

        You can do whatever you want to pictures of Pluto (or your selfies) – nobody is claiming that is scientific evidence supporting global warming (or any other) theory.

        If you understood science, you wouldn’t have to be reminded of this.

    • It’s okay to adjust if it shows unprecedented warming, so why not adjust to show this is a ho hum nothing special warming.

    • It’s a temporal thing Mosh, there’s nothing wrong with adjusting raw data at the time when a weather station is moved/changed, or hasn’t worked. It’s adjusting raw data after it’s been used for 80-100 years that’s smelly.

    • I love the way warmists find one point that they don’t understand, and then harp on it over and over again.
      Adjusting data is ok so long as you present the raw data, plus your methods and reasons for adjusting.
      This allows others to review your adjustments and determine if they are reasonable and correct.

      When your climate scientists start doing this, they will come in for a lot less criticism.

  7. A caution related to taking one part of the globe and extrapolating global synchronicity (click on link below and then click on the “[PDF] from columbia.edu” link). Given what we currently observe under a given weather pattern variation/climate regime, it is often the case that certain warm and cold patterns describe a climate regime. The land will be cold here but warm there. Or maybe less cold here while warm there. Or an oceanic warm pool will shift positions with a cold pool (PDO anyone?). Or the jet stream loops further to the East instead of over the North American plains. Who is to say that during the MWP, there was NOT extensive Antarctic sea ice while Greenland was host to Viking farmers? A case in front of our noses: We have been and still are in a warm period and Antarctic sea ice has been above its mean.

    So no, proxies all over the globe may not show a consistent, synchronized warm trace. Instead they may be marked by variations that could indeed be the pattern when a warm period is upon us, and is what Mann uses mistakenly to dismiss the existence of a global MWP climate regime. When a cold period is upon us, we will see a different pattern. If Mann is alive at that time, he may resurrect global warming as the Antarctic ice for example, begins to show evidence of shrinking. Why is that a good bet? Mann does not appear to be a person willing to learn. Unfortunately, this debate is peppered on both sides with folks like him.

    https://scholar.google.com/scholar?hl=en&q=Inter-hemispheric+temperature+variability+over+the+past+millennium+Raphael+Neukom&btnG=&as_sdt=1%2C38&as_sdtp=

  8. Invasion of Batu Khan[edit]
    The vast Mongol hordes of around 35,000 mounted archers, commanded by Batu Khan and Subutai, crossed the Volga River and invaded Volga Bulgaria in the autumn of 1236. It took them a year to extinguish the resistance of the Volga Bulgarians, the Cumans-Kipchaks, and the Alani.

    Sacking of Suzdal by Batu Khan in February 1238; miniature from the 16th-century chronicle.
    In November 1237, Batu Khan sent his envoys to the court of Yuri II of Vladimir and demanded his submission. A month later, the hordes besieged Ryazan. After six days of bloody battle, the city was totally annihilated. Alarmed by the news, Yuri II sent his sons to detain the invaders, but they were soundly defeated. Having burnt down Kolomna and Moscow, the horde laid siege to Vladimir on February 4, 1238. Three days later, the capital of Vladimir-Suzdal was taken and burnt to the ground. The royal family perished in the fire, while the grand prince retreated northward. Crossing the Volga, he mustered a new army, which was totally annihilated by the Mongols in the Battle of the Sit River on March 4.

    Thereupon Batu Khan divided his army into smaller units, which ransacked fourteen cities of modern-day Russia: Rostov, Uglich, Yaroslavl, Kostroma, Kashin, Ksnyatin, Gorodets, Galich, Pereslavl-Zalessky, Yuriev-Polsky, Dmitrov, Volokolamsk, Tver, and Torzhok. Chinese siege engines were used by the Mongols under Tului to raze the walls of Russian cities.[4] The most difficult to take was the small town of Kozelsk, whose boy-prince Vasily, son of Titus, and inhabitants resisted the Mongols for seven weeks, killing 4,000. As the story goes, at the news of the Mongol approach, the whole town of Kitezh with all its inhabitants was submerged into a lake, where, as legend has it, it may be seen to this day. The only major cities to escape destruction were Novgorod and Pskov. The Mongols were advancing on Novgorod but unexpectedly turned back at the site mentioned as Ignach Cross, of which the exact location is not known. Refugees from southern Rus’ moved mostly to the northeast, into the forested region with poor soils between the upper Volga and the Oka Rivers.

    In the summer of 1238, Batu Khan devastated the Crimea and pacified Mordovia. In the winter of 1239, he sacked Chernigov and Pereyaslav. After many days of siege, the horde stormed Kiev in December 1240. Despite the resistance of Danylo of Halych, Batu Khan managed to take two of his principal cities, Halych and Volodymyr-Volynskyi. The Mongols then resolved to “reach the ultimate sea”, where they could proceed no further, and invaded Hungary and Poland.

    Yes its Wikipedia, but the above gives you a good account. Oh and do note the dates, and that this is Russia. Ah can we say medieval warm period.
    michael

    • Each Mongol soldier kept three or four ponies, with more animals in the logistics train, so imagine a ravening horde with perhaps 120,000 horses.

    • And where did all these Mongolians appear from? Currently most of Mongolia is a frozen wasteland for a good part of the year frequently afflicted by Zuds (deep deadly freezes that kill anything outside, like say war ponies). I believe Mongolia became something of a temperate garden at the start of the MWP allowing the Mongol hordes to flower.

    • Very sensible explanation. About 700 – 800 years earlier (about 450 – 550 AD) a ‘mini-ice age ocurred and drove the Germanic and Slavic tribes to occupy totally or partly the Roman Empires ‘West and East’. The cooler weather up North was however favorable to the Southern regions at first drier but later wetter ones. The Middle East and North-Africa flourished both again. The population boom in Arabia supplied numerous nomad-warriors to both the Byzantines and Sassanids. After the devastating wars between those empires, some of these nomadic warriors were able to supplant them and conquer the entire Middle-East and North-Africa (700 – 800 AD).. Towards 900 – 1.000 AD they adopted a creed now known as Islam. The onset of a new warming and drier period wasn’t very beneficial for that region. The Crusaders came (1.100 AD) and won and finally the Mongols came also and devastated the entire Middle-East (1.250 AD).

  9. I recently cut down some trees in my garden.
    Upon examination the pattern of tree rings shows no evidence that seasonal variation of temperature existed in previous years. i.e there was formerly no variation in temperature between winter and summer.
    These finding are in striking contrast to the evidence provided by historical accounts.
    I also searched in the local pond for the plane, MH370 and did not find it.
    Hence, seasonal variation in temperatures did not formerly exist and the plane MH370 does not and did not ever exist.
    When I extended my tree ring examination to show modern yearly variation the technique showed fundamental limitations. i.e. it failed to correspond to established reality.
    As a result I have bodged the representation of my findings by chopping off the familiar modern period and replacing that section of the graph with some other stuff which was derived from another methodology.
    The result of all of these efforts is frankly a big pile of shit which I intend to force upon the world, for ideological reasons. And for the sake of self-promotion.
    People will still be discussing the fruits of my witless bullcrap, even in a decade or two.
    Which is success of sorts.
    In addition, MH370 has still not been found. Proving that my initially assessment is still valid.
    P.S. thanks for all the money.

    • I have three ash trees in my back yard which somehow have been missed by the Emerald Ash Borers that have invaded Ohio. I do not plan to cut them down unless the borers find them but they do point out the idiocy of using tree rings for determining temperature. I planted the trees about 20 years ago on the same day. They are about 50 feet apart. All three trees have different trunk diameters ranging from 10 to 14 inches.
      Why are they all different?
      DNA?, depth of water table?, amount of sun they receive?, variations in nutrients in the soil?
      If Michael Mann we to cut them down and study their tree rings which one would he use to determine the temperature over the last twenty years?

      • Short answer: none of them.
        Since dendroclimatology fails to reproduce modern warming. The so-called divergence problem.
        As explained here on wikipedia:
        “While the thermometer records indicate a substantial warming trend, tree rings from these particular sites do not display a corresponding change in their maximum latewood density or, in some cases, their width. This does not apply to all such studies. Where this applies, a temperature trend extracted from tree rings alone would not show any substantial warming. The temperature graphs calculated from instrumental temperatures and from these tree ring proxies thus “diverge” from one another since the 1950s, which is the origin of the term. This divergence raises obvious questions of whether other, unrecognized divergences have occurred in the past, prior to the era of thermometers”.
        It certainly does raise that question. It’s the question that we have all been asking.
        The entire exercise also raises the question that you allude to. Which is the question of whether the temperature is actually the most significant factor in determining the growth rate of trees.
        And even if it is, then how are we to eliminate the influence of other competing factors.
        These are the questions that should have been asked, even if this enterprise had been a project for secondary school.
        However, since the results were signed off by an “expert in the field”, the world failed to ask these questions and failed to demand the answers.
        Then there is the issue of the truncation of a graph showing data from one methodology and the supplanting of the modern period with data derived using an altogether different technique.
        At best misleading, at worst plain deception.
        In summary what was presented is wrong in so many ways that it should be regarded as having almost no connection with reality whatsoever.
        Throw in the fact that the scientist behind it was motivated to prefer a certain outcome and we are beyond wrong. We are beyond “not even wrong”.
        It is mind boggling that so many kinds of wrong were compressed into such a minor piece of guff and then sold to the world as “science”.

      • You don’t need to cut them down. All you need is what is known in forestry as an increment borer. It takes a neat core of the tree. It does take some practice to accurately hit the heart of the trunk. Mann would clearly use the one that laid on the most growth most recently.

  10. Lots of great refutation to Mann’s research upthread.

    I went to the Union’s site and read the columns, but noticed no one appears to be able to comment on them. I’m a Californian, so it affects me personally.

    Mann made several claims in his rebuttal,two of which we know to be patently and ridiculously false , especially the one about SKS. Heck, they’ve even deleted my comments there (haven’t even gone there for years, but they are how I found WUWT and so for that I’m grateful –smile) and I try my best to behave in a reasonable civil manner in public (even if I’m mostly anonymous) including online.

    Perhaps this is an opportunity to make Mann put up or shut up in public.
    As a “scientist” he needs to validate his claims of :”funding by the fossil fuel industry”, and “a website run by a scientist”, by providing the facts for all to read: Which specific “fossil fuel industries” are funding which specific scientists (including the ones on which smear campaigns have been attempted but unfounded)? Who exactly is the “scientist” that runs SKS and in what field does he hold advanced credentials?
    He is the one who made reference to “talking points”. Lets call him out on his own propaganda.

  11. Esper has long been a thorn in Mann’s side. Mann has on occasion attempted to bully him, but Esper has remained independent and resolute.

  12. Mann “et al”‘s motto: “Any delusion to reach the desired conclusion”.

    And as long as I’m treading on sueable ground, yet another replay of…

    Stopping By Yamal One Snowy Evening
    by Guess Who

    What tree this is, I think I know.
    It grew in Yamal some time ago.
    Yamal 06 I’m placing here
    In hopes a hockey stick will grow.

    But McIntyre did think it queer
    No tree, the stick did disappear!
    Desparate measures I did take
    To make that stick reappear.

    There were some corings from a lake.
    And other data I could bake.
    I’ll tweak my model more until
    Another hockey stick I’ll make!

    I changed a line into a hill!
    I can’t say how I was thrilled!
    Then Climategate. I’m feeling ill.
    Then Climategate. I’m feeling ill.

  13. All the climate propaganda could perhaps be renamed “Goebbels warming.” All you have to do to bust the consensus myth is to look at the Cook et al “study” Of the 4,000 odd that offered an opinion from the 11,944 sample size, only 64(some suggest it is just 41) articles gave a qualified verdict that humans are the dominant cause of global warming/climate change. This is around 1%-this is a consensus?. Classifying those papers that used very much inconclusive terminology(weasel words-may, might, could) as positive evidence of a consensus is blatantly misleading. Real science is about qualified conclusions.
    Do note, climate “action” can only make any sense if humans ARE the dominant cause of global warming/ climate change. If humans were say 50% of the “problem”, totally destroying humanity would only “fix” half the “problem.”

  14. Don’t forget that the Lloyd study looked at the last 80 centuries and found nothing unusual or unprecedented about our slight recent warming. In fact he found about an average 1 C deviation per century.
    Our warming comes after the end of one of the coldest periods of the last 10,000 years, called the LIA. And the HAD 4 data only shows about 0.8 C since 1850. They’ve been conning us for over 30 years.
    Here’s Lloyd’s abstract————-

    .O.Box 652 Cape Town 8000 lloydp@cput.ac.za
    ABSTRACT
    There has been widespread investigation of the drivers of changes in global
    temperatures. However, there has been remarkably little consideration of the
    magnitude of the changes to be expected over a period of a few decades or even a
    century. To address this question, the Holocene records up to 8000 years before
    present, from several ice cores were examined. The differences in temperatures
    between all records which are approximately a century apart were determined, after
    any trends in the data had been removed. The differences were close to normally
    distributed. The average standard deviation of temperature was 0.98 ± 0.27
    o
    C.
    This suggests that while some portion of the temperature change observed in the
    20th century was probably caused by greenhouse gases, there is a strong likelihood
    that the major portion was due to natural variations.

    And here’s the study———— http://www.researchgate.net/publication/276276180_An_Estimate_of_The_Centennial_Variability_of_Global_Temperatures

  15. Too much fun:

    “As a consequence, earlier warm periods during the late 14th and 15th centuries appear warmer,
    though not statistically significant, compared to the late 20th century.”

    We already understand that the the era centered on the MWP (9th -11th centuries) were as warm, or warmer than today. Adding a few hundred additional years to the warm period lends in understanding how forests w/ mature trees were growing in the then future path of the Mendenhall and Exit Glaciers up in Alaska, only to be be buried under the ice as it did advance, and now to be revealed once again, as this naturally occurring warm cycle is just getting under way.

    May the wonderful warmth continue.

    • Temperatures remained higher than now into the 14th century. They deteriorated through the 15th and 16th centuries (Spoerer Minimum), hitting bottom in the depths of the LIA in the 17th century (Maunder Minimum). There was improvement for part of the 18th century, but the LIA cooled again during the early 19th century (Dalton Minimum).

  16. From the shadows.

    Rather ask yourself why in the world , the expert global panic guy would be so worried by an op-ed piece in a ‘chuck wagon’ (my own opinion because I consider my own county paper the squares villi screamer ) paper op-ed piece he felt that he had to slam down on this?

  17. baseless talking points that have their origin in fossil-fuel industry-funded climate change denial propaganda

    That’s all that Manns got? The man has gone beyond pathos into tragedy. Is he worthy of pity now?

    Nah.

  18. Leaving aside whether it’s appropriate to take a study of one area as a refutation of Mann’s work which claimed to reconstruct temperature of the entire northern hemisphere, how are you guys not bothered by the fact pretty much the entirety of this reconstruction is adjusted? The first 800 years or so of it gets adjusted:

    The removal of δ13C level differences and age-trends
    resulted in a millennium-long record indicating higher
    chronology levels back in time, compared to its non
    detrended “raw” counterpart (Fig. 2). The detrending
    procedure corrected the systematically lower δ13C values
    of biologically younger rings likely triggered by the (i)
    uptake of CO2 enriched ambient air from soil respiration
    (Francey and Farquhar, 1982), and (ii) decreased hydraulic
    resistances and higher stomatal conductance of smaller
    trees (McDowell et al., 2002). As a consequence, the
    residual timeseries, between the raw and detrended chronologies,
    increases from –0.26°C in the 17th century to
    –0.74°C in the 13th century.

    Then the everything after 1850 gets adjusted:

    A major constraint of the new reconstruction is the
    substantial difference in recent temperature trends caused
    by post-1850 δ13C correction procedures. The correction
    applied here, accounting for atmospheric 13C/12C ratio
    and plant physiological effects, appeared most suitable as
    it produced a timeseries without any trend in residuals
    after regressing against instrumental temperatures. However,
    developing objective criteria for post-1850 correction,
    independent of the goodness of fit with instrumental
    target data, are needed to establish δ13C based reconstructions
    as an additional proxy for studying climate variations
    over past millennia.”

    The authors themselves even caution that the adjustments may not be right:

    Our new δ13C based reconstruction seems to capture
    20th century temperature trends better than the existing
    MXD records. The performance improvement is largely
    determined by the applied atmospheric CO2 correction.
    We considered the Kur, Fen, and Atm corrections in our
    reconstruction attempts, choosing the annually resolved
    reconstruction containing the least trend in residuals after
    calibration against instrumental summer temperatures
    (–0.01°C/decade for Kur, +0.06°C/decade for Fen, and
    –0.10°/decade for Atm; Fig. 6). However, the decision to
    favor one δ13C correction scheme over another is generally
    not well justified (Treydte et al., 2009), and perhaps
    represents the most significant constraint of the new
    summer temperature reconstruction presented here.

    When temperature station records get adjusted, people throw fits claiming it is no longer “data.” When these guys adjust their data, everyone gets excited and labels it “facts” and “hard science.” Whats up with that?

    • brandon…
      EWhen glaciers recede, and reveal corpses, mining tools, trees and the like, what is one to make of it?
      Many would conclude that tress and mines and people were there before the glaciers advanced..what is your conclusion?
      the people dug holes in the ice and dropped their tools, mined the earth and dragged trees into the ice? really?

    • Brandon,
      Sometimes, data adjustments could be likened to brushing the hair out of one’s eyes. But some adjustments have been wielded as a tool, conveying a rendered truth as if seen by a blindfolded man, facing a window with curtains drawn.

      • Alan Robertson:

        Brandon,
        Sometimes, data adjustments could be likened to brushing the hair out of one’s eyes. But some adjustments have been wielded as a tool, conveying a rendered truth as if seen by a blindfolded man, facing a window with curtains drawn.

        And remarkably, the distinction seems to always be whether or not one likes the results which arise from the adjustments. Amazing how that happens, no?

      • Brandon Shollenberger,

        And remarkably, the distinction seems to always be whether or not one likes the results which arise from the adjustments. Amazing how that happens, no?

        Your conjecture has merit, but only in narrow regard. Manipulation of data to return a result which satisfies an agenda is purposeful lying.

      • “And remarkably, the distinction seems to always be whether or not one likes the results which arise from the adjustments. Amazing how that happens, no?”

        And coincidentally, the people doing the adjusting always get exactly the result that they like, don’t they?
        The result, by the way, that just happens to back up the story they are pushing.
        You are wrong, though.
        It is not in the slightest bit amazing.
        It is 100% predictable.
        Isn’t it?

    • ‘Mann’s work which claimed to reconstruct temperature of the entire northern hemisphere’ but in pratice only covered a very small part of it , although that has never stopped Mann’s supporters from claiming it is ‘valid ‘ for the whole planet .

      When Mann ‘claims ‘ it is always best to be carrying salt with you.

    • Nobody is claiming the tree-derived temperatures are “data”, Brandon. But when you have a highly calibrated instrument measuring the exact quantities under consideration (I.e. Temperature by a thermometer) then it’s a bit different to say “that guy back in 1938 didn’t know what he was doing, so I’ll simply lower his measurement until I get a result that fits my thesis”

      • Taylor Pohlman:

        Nobody is claiming the tree-derived temperatures are “data”, Brandon.

        Um, this post explicitly says things like:

        What I find most interesting is their graph showing how they calibrated the δ13C data against the instrumental temperature record.

        So clearly, the adjusted values are being labeled data like I said. The only quibble you can raise is that the “temperatures” derived from tree rings aren’t being labeled data, but I never claimed they were. I said the authors results, which depend entirely upon adjustments, are being promoted as good with their “data” being accepted despite the massive amounts of adjustments it undergoes.

        But when you have a highly calibrated instrument measuring the exact quantities under consideration (I.e. Temperature by a thermometer) then it’s a bit different to say “that guy back in 1938 didn’t know what he was doing, so I’ll simply lower his measurement until I get a result that fits my thesis”

        That’s not the rationale for any of the adjustments. If you think that’s a fair characterization of the reasoning behind any adjustment to temperature data, you have no idea what you’re talking about. If you’re just intentionally misstating the case to paint people as doing inappropriate things you know they don’t do, you’re being dishonest. Either way, your comment is pretty bad.

  19. The graphs shown in the above article look awfully noisy, with low correlation to every version of every version of GISS and NCDC (even as of 2008 and most curves significantly differ from GISS/NCDC versions of around 2000), every version of HadCRUT (even the satellite-TLT-correlating champion Hadcrut3 and the older HadCRUT2), even paleoclimate composites that rightwingers like such as sometimes Moeberg and especially Loehle. Also, usage of JJA without mention of full-year figures gets me quick to suspect cherrypicking.

  20. “I wonder if Mann’s Bristlecone Pine tree core samples from MBH98 still survive”

    If they do, they won’t for long.

  21. d13C in the old xylem we call wood seems a very dubious proxy for temperature. The xylem carries water and nutrients up from the ground. Are you measuring the 13C from the roots? Is the notion that 13carbohydrate produced by photosynthesis and dispersed by the phloem shows up in the current year xylem? Or was that last year’s stored in the roots.

  22. Speaking as a layman, if there can be no way of accurate computer measurement of global cloud/water vapor and there is no inclusion of sunspot activity in these hypotheses – what are we all talking about?
    Please convince me in a good old Occam’s razor way. Like the majority of the world’s governments are apparently being convinced.

  23. I posted a comment on Mann’s facebook page under his post regarding that article. I bet it gets deleted.

    “Dr. Mann, you stated that Skeptical Science is a scientist run site. Would you please tell us the name of the scientist that runs that site? Also, what is his field of expertise?”

  24. With all this talk of reconstructions, I did want to make a joke about my desire to “reconstruct” somebody’s face.
    But, unfortunately the object of my joke appears already to be an eager litigant with zero sense of humour.

  25. Proxy also captures temp fiddling, notably the year before satellite record started – temp is pushed down to give a steeper upslope. I think a corrected instrument record would give a better R#2 factor. It would be worthwhile to do a number of similar tests to verify the instrument record is systematically fiddled as we can be sure it has been.

  26. This is a local record. If you want to take it as representative of a global record then you have dug yourselves a trap and then fallen into it. If this were a global record, you would have just eliminated the LIA as a global phenomenon. You don’t really want to do that, do you?

      • Tony
        Your admonition should be directed against the majority of other correspondents here who, apart from a few, quite clearly think this paper is about about Mann and the hockey stick. No doubt they are taking their cues from the introduction. If the article had simply quoted the title and abstract from Esper’s paper and said “ Here is a paper about the Pyrenees which tells you nothing about the validity or otherwise of the HS” would the comments have been the same?

      • The comments are irrelevant. You were commenting on the post, I was summarising the post. If commenters can’t understand plain english, as possibly you have difficulty with, I can’t help you.

      • Tony,
        So you agree that my comments were correct and those of other commentators were , in your words, irrelevant. I am sure they appreciate that.

  27. I know little of science and have even less understanding, but great admiration for, all of you knowledgeable writers. Even so, there is a place for such as I on this site since I have followed Mark Steyn’s remarkable fortitude and patience in this important battle. So on a lighter note and with little intellectual credentials, I offer this:

    With wit and elan
    Steyn comments to Mann
    In a word your hockey stick sucks
    What’s next you boob
    A graffic to prove
    The circumference of tree-ring pucks?

  28. I’ll be the antagonist, although I know I will get a lot of negativity. Climate change is real, humans are contributing, and we are going to see big changes in the near future. It’s already happening. I have a cousin who does mass farming in Oklahoma and would not be considered a liberal at all. She was recently telling me how massive the changes have been in the last 10 years. When you can plant your crops, what crops you can grow, how much they will yield. These are the people on the ground that really see the effects. Most of us are spending our time in climate controlled buildings and don’t realize that the extra rain, longer springs, droughts, etc are very REAL for people that depend on predicable weather cycles.

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