Validity of “A Reconstruction of Regional and Global Temperature for the Past 11,300 Years”

It seems that Marcott et al isn’t all that it is cracked up to be. Dr. Easterbrook takes a good hard look at the paper.

Guest post by Dr. Don J. Easterbrook

(Note: Because of the far-reaching implications of the conclusions in this paper and the nature of the data, this review will be broken into several segments. This is Part I).

The news media has exploded with extraordinary claims of ‘unprecedented global warming’ asserted in a paper “A Reconstruction of Regional and Global Temperature for the Past 11,300 Years” by Marcott, Shakun, Clark, and Mix in Science. A NY Times headline reads “Global Temperatures Highest in 4,000 Years,” and proclaims that global warming will “surpass levels not seen on the planet since before the last ice age.”

Here are some of the truly extraordinary assertions in the paper:

1. “Current global temperatures of the past decade … are warmer than during ~75% of the Holocene temperature history.”

2. “Global mean temperature for the decade 2000–2009 …. are, however, warmer than 82% of the Holocene”

3. ~0.6°Cof warming from the early Holocene (11,300 yr B.P.) to a temperature plateau extending from 9500 to 5500 yr B.P.. This warm interval is followed by a long-term 0.7°C cooling from 5500 to~100 yr B.P. (Fig. 1B).

4. Early Holocene (10,000 to 5000 years ago) warmth is followed by ~0.7°C cooling through the middle to late Holocene (<5000 years ago), culminating in the coolest temperatures of the Holocene during the Little Ice Age, about 200 years ago.

5. “Global temperatures are warmer than at any time in at least 4,000 years.”

6. “Over the coming decades are likely to surpass levels not seen on the planet since before the last ice age.”

7. “Surface temperature reconstructions of the past 1500 years suggest that recent warming is unprecedented in that time.”

8. Our global temperature reconstruction for the past 1500 years is indistinguishable within uncertainty from the Mann et al. (2) reconstruction

9. A cooling trend from a warm interval (~1500 to 1000 yr B.P.) to a cold interval (~500 to 100 yr B.P.), which is approximately equivalent to the Little Ice Age (Fig.1A). This similarity confirms that published temperature reconstructions of the past two millennia capture long-term variability, despite their short time span (3, 12, 13).

10. “Global temperature of the early20th century (1900–1909) was cooler than>95% of the Holocene.”

11. “Global temperature….. has risen from near the coldest to the warmest levels of the Holocene within the past century.”

12. A heat spike like this has never happened before, at least not in the last 11,300 years. “If any period in time had a sustained temperature change similar to what we have today we would have certainly seen that in our record. ” It is a good indicator of just how fast made-climate change has progressed. (Marcott quoted on CNN)

They arrived at these conclusions by “reconstructing regional and global temperature anomalies for the past 11,300 years from 73 globally distributed records” “largely derived from marine archives (~80%),” including paleoclimate temperature proxies such as alkenone, planktonic foraminifera Mg/Ca 23, fossil pollen, ice-core stable isotopes, and Mann et al. (2008) tree ring reconstructions. Although a list of sources of the data from the 73 sites is provided in an appendix, nowhere is any real data presented, so assessing the validity or accuracy of the original data is not possible without digging out all of the source papers. Just how accurate are these marine temperature reconstructions? We really can’t tell without any original data for specific sites. There are two issues here: (1) How accurately can the paleotemperatures be measured, and (2) how accurate is the dating of the material? The accuracy of the paleotemperature measurement depends on the method used and since multiple methods were used, the results are a mixture of varying accuracies. Dating marine fossils (80% of the samples used in the study) depends on radiocarbon measurements, and the marine lag effect. Radiocarbon in marine organisms is generally 400-800 years older than land organisms, so correction factors must be used, and this affects the accuracy of dates.

Eighty percent of the source data sites were marine, so temperatures from 80% of the data set used in this paper record ocean water temperatures, not atmospheric temperatures. Thus, they may reflect temperature changes from ocean upwelling, changes in ocean currents, or any one of a number of ocean variations not related to atmospheric climates. This in itself means that the Marcott et al. temperatures are not a reliable measure of changing atmospheric climate.

The paper consists entirely of complicated computer manipulations of data (definitely not light reading for anyone but computer modelers) and conclusions. As Andy Revkin (Dot Earth) points out, This work is complicated, involving lots of statistical methods in extrapolating from scattered sites to a global picture, which means that there’s abundant uncertainty.”

Without any original data to assess, how can we evaluate the validity of the conclusions? The only way is to check the conclusions against well-established data from other sources. As Richard Feynman eloquently described the scientific method, once hypotheses (conclusions) are set out, their consequences can be checked against experiments or observations. If a hypothesis (conclusion) disagrees with observations or experiments, it is wrong. It doesn’t make any difference how beautiful the hypothesis (conclusion) is, how smart the author is, or what the author’s name is, if it disagrees with data, experiments, or observations, it is wrong. Period. So let us apply this method to the conclusions of this paper and test them to see if they are right or wrong.

First, let’s test the Marcott et al. 11,300 year temperature curve against the GISP2 Greenland ice core oxygen isotope record (Alley, 2000) (Figure 1 below). The Greenland ice core data is widely considered to be the ‘gold standard’ of quantitative paleo-temperature measurements with thousands of accurately dated analyses covering many thousands of years. From the Alley (2000) curve, it is readily apparent that temperatures during virtually all of the period from 10,000 to 1,500 years ago were warmer than at present and 85% of the past 10,000 years were warmer than present. The curve extends to 95 years ago, but even if we add 0.7°C for warming over the past century (dashed line), temperatures were still dominantly warmer than present.

clip_image002

Figure 1. Comparison of Greenland ice core temperatures and Marcott et al. temperatures for the past 10,000 years. (Top curve modified from Alley, 2000 based on data from Cuffy and Clow; bottom curve modified from Marcott et al., 2013)

Let’s compare this to the Marcott et al. conclusion “Current global temperatures of the past decade … are warmer than during ~75% of the Holocene temperature history” and “Global mean temperature for the decade 2000-2009 ….are warmer than 82% of the Holocene”(lower curve, Figure 1). The Marcott et al. conclusion is totally at odds with the Greenland ice core data. But why should we believe the ice core data rather than the Marcott et al. computer generated curve? Well, the ice core curve is based on thousands of isotope measurements that reflect paleotemperatures and the chronology is accurate to within about 1-3 years, whereas the Marcott et al. curve is essentially based on computer-manipulated data with multiple data types using different technologies with varying accuracy and chronology accurate only within hundreds of years. Marcott et al. assert that this doesn’t matter over a period as long as 10,000 years. But, of course, the accuracy of a body of data depends on the sum of the accuracies of its individual components, e.g. you can’t claim microscopic accuracy from a bulldozer, no matter how you manipulate the data.

What about the global implications of the Greenland ice core data? The cores come from specific sites on the Greenland ice sheet, so doesn’t the data pertain just to those particular places? That’s true, but the real question is does it mirror the global climate? The answer to that is definitely yes—correlation of temperatures from the ice cores with global glacial fluctuations is clear and unequivocal. Even small fluctuations of ice core paleo-temperatues can be accurately correlated with advance and retreat of glaciers globally (this topic will be expanded later). In addition, modern Greenland temperatures mimic global temperatures—comparison of temperature records from weather stations in Greenland with global temperatures confirm that Greenland marches in lock step with global climate (Figure 2). Thus, we can conclude that paleo-temperatures in Greenland ice cores are representative of global temperatures.

clip_image004 clip_image006

Figure 2. Comparison of Greenland temperatures

Let’s look at some specific features of the Marcott et al. curve. As shown in more than 3,000 publications, the Medieval Warm Period (MWP) is widely recognized to have been somewhat warmer than present Figure 1). In the past 10,000 years, at least six other warm periods of magnitude equal to the MWP occurred; nine other warm periods that were 0.5°C warmer than the MWP occurred; two warm periods that were 1°C warmer than the MWP occurred; and three warm periods that were 1.5°C warmer than the MWP occurred. All of these periods warmer than the MWP clearly contradict the Marcott et al. conclusions.

The Marcott et al. conclusions that “Current global temperatures of the past decade … are warmer than during ~75% of the Holocene temperature history” and “Global mean temperature for the decade 2000-2009 ….are warmer than 82% of the Holocene” are clearly contrary to measured, accurate, real-time data and thus fail the Feynman test, i.e., they are wrong.

This rebuttal addresses only part of the Marcott et al. paper. To include analyses of all the issues would take a much longer response, so this is just Part 1. The next part will consider some or all of the remaining conclusions listed at the beginning.

References

Alley, R.B., 2000, The Younger Dryas cold interval as viewed from central Greenland: Quaternary Science Reviews, vol. 19, p.213-226.

Cuffey, K.M. and Clow, G.D, 1997, Temperature, accumulation, and ice sheet elevation in central Greenland through the last deglacial transition: Journal of Geophysical Research 102:26383-26396

Marcott, S.A, Shakun, J.D., Clark, P.U., and Mix, A.C., A Reconstruction of Regional and Global Temperature for the Past 11,300 Years: Science, vol. 339, p. 1198-1201.

==============================================================

Geologist Dr. Don J. Easterbrook, Emeritus Professor at Western Washington University, who has authored eight books and 150 journal publications. His CV is here

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97 Responses to Validity of “A Reconstruction of Regional and Global Temperature for the Past 11,300 Years”

  1. Kurt in Switzerland says:

    “Thus, we can conclude that paleo-temperatures in Greenland ice cores are representative of global temperatures.”

    Just because a strong correlation was found in the 20th century doesn’t mean that this some correlation would also exist throughout the Holocene.

    Kurt in Switzerland

  2. lurker, passing through laughing says:

    Yet again the AGW prmotion industry relies on data with dubious provenance, doubtful precision and no real controls to make extraordinary claims.

  3. j ferguson says:

    Thank you Dr. Easterbrook for going over this paper. It is a bit dismaying that it should be receiving the widespread attention it is, including the NBC Nightly News, given that it is as shaky as you have shown us.

    It is equally dismaying that when the thing is thoroughly demolished, that never makes it to the mass media.

  4. Russ says:

    Reblogged this on If You Voted For It — You Own It and commented:
    We will not hear anything from the local lefty crickets on this post, as it does not fit the AGW Cults play book.

  5. jack morrow says:

    You can refute them everyday but they will continue their story because they are getting money to do so. Until the money stops , we will have to get use it.

  6. michael hart says:

    Haven’t read the paper (paywalled), but something to look out for: I recall (correctly, I hope!) the withdrawn Gergis paper as covered by Steve MacIntyre at Climate Audit-

    http://climateaudit.org/2012/07/24/was-gergis-et-al-withdrawn/

    -made use of a sweeping set of various proxies welded into a grand synthesis. I think they used a whole bunch of coastal proxies as generally representative of the oceans.

    During time periods when ice sheets are expanding/contracting and sea levels falling/rising, would it be possible to find any worse proxies than those located near the coast?

  7. Doubting Rich says:

    Kurt in Switzerland
    Dr Easterbrook did not confine his evidence to the temperature records. He pointed out that the Greenland data closely follow another reliable proxy, glacial extent.

  8. Theo Goodwin says:

    Marcott and friends included Mikey’s hockey stick:

    “8. Our global temperature reconstruction for the past 1500 years is indistinguishable within uncertainty from the Mann et al. (2) reconstruction.”

    Why would anyone do that? Mikey’s hockey stick is the poster child for how not to do research in paleoclimatology. In “hiding the decline,” the Team demonstrated that they had no concept of the empirical research necessary to validate the proxies that they used to obtain temperature measurements. When their proxies (trees rings) declined, giving evidence of lower temperatures rather than higher, they replaced their own data with thermometer readings that showed higher temperatures. But their real shortcoming as scientists was revealed in their lack of desire to discover what caused the decline in their proxies. They undertook no empirical research on proxies to learn what caused changes in them. Unfortunately for the field of paleoclimatology, the lack of empirical research to determine what actually causes their proxies (tree rings in this case) to grow or not is all but universal. In recent years, some fourteen years after publication of the hockey stick, Briffa has taken some steps to remedy The Team’s lack of curiosity. But that research has not informed The Team’s hockey stick.

    All proxy data must be subjected to rigorous experimentation for the purpose of validation. One cannot simply assume, as The Team did, that you know what causes changes in the growth patterns of your proxies. Until paleoclimatology addresses this need for validation, paleoclimatologists can hardly call themselves scientists.

    Marcott and friends simply bundle 73 studies that use proxies. The fact that they included Mann’s hockey stick demonstrates that they are uninterested in empirical science. At this late date, some fifteen years after publication of the hockey stick, there is no reason that we should have to address the scientific or moral errors involved in the hockey stick research and publication. I am shocked that NSF and one of its program directors would publicly express support for Marcott’s paper.

  9. John Tillman says:

    Kurt:

    Dr. Easterbrook stated that the Greenland ice core data do mirror global climate both since 1880 (Fig 2) & for paleo-temperatures. He wrote (& will write more):

    “Even small fluctuations of ice core paleo-temperatues can be accurately correlated with advance and retreat of glaciers globally (this topic will be expanded later)….(Discussion of modern data.) Thus, we can conclude that paleo-temperatures in Greenland ice cores are representative of global temperatures.”

    Please note also these references, dealing with the end of the Pleistocene & early Holocene:

    Alley, R.B., 2000, The Younger Dryas cold interval as viewed from central Greenland: Quaternary Science Reviews, vol. 19, p.213-226.

    Cuffey, K.M. and Clow, G.D, 1997, Temperature, accumulation, and ice sheet elevation in central Greenland through the last deglacial transition: Journal of Geophysical Research
    102:26383-26396

  10. numerobis says:

    Warming over the past century has been about 0.8C globally, but about double that in the Arctic. I don’t know the precise value for the location of the ice core; could be more or less.

    Regardless, the climate in one point is not the global climate. The Marcott paper (like an old paper by Mann et al) is notable precisely because they do the hard work of trying to get a global picture. You can’t refute their results by saying that in one location the results are different.

  11. Steve Keohane says:

    Thanks Dr. Easterbrook for this presentation. It is a real can of worms. In looking through any files I might add as information, I have a series of circumpolar histories by Amanda Graham, from Yukon college, an educator with an interest in circumpolar studies. In what I have read in a few of the paleo-histories, everything seems to observational science. No CO2, hysteria nor other editorializing. Haven’t found any gross inconsistencies with what I’ve read over the past fifty years,archeologically. There may be clashes with ‘climate science’.

    http://ycdl4.yukoncollege.yk.ca/~agraham//nost202/timetables.htm

  12. Peter Miller says:

    “BS baffles brains” is one of the oldest cons in the world.

    Very simply, it means if you want to sell a concept or something, which you know to be rubbish, you surround it with complicated, unverifiable ‘proof’. In addition, You elevate your language to a level where few can understand it.

    Mining scams and this type of climate science have a lot in common; I have uncovered lots of the former. In the case of ‘climate science’, the more obvious cases of BS are trumpeted by the likes of the BBC and the Guardian in the UK and by Al Gore’s cronies in the US.

    If there is no raw data and/or all complicated, unexplained re-interpretations of other research, then the new findings are almost 100% guaranteed to be complete BS.

    For most geologists, it is difficult to tell the methodologies apart of mining scams and much of today’s climate science.

  13. RHS says:

    How well can a record be interpreted when the record is written/created over several thousand years? Marine sediments would seem very difficult to “read” since there is ocean circulation and sediments from today may take over a year to be deposited. It just seems easy to find any message one would want…

  14. scarletmacaw says:

    Correct me if I’m wrong, but doesn’t the Ice core data measure temperature by using the O18/O16 ratio? If so, wouldn’t that ratio be tied to the global atmospheric concentrations rather than local, so that the ice core data DOES measure global temperature?

  15. Steven Mosher says:

    ‘The paper consists entirely of complicated computer manipulations of data (definitely not light reading for anyone but computer modelers) and conclusions. ”

    Nonsense. There is nothing very complicated in the paper. When a reviewer tells you that easy is hard, you should ignore the reviewer because he has just disqualified himself.

  16. Theo Goodwin says:

    numerobis says:
    March 11, 2013 at 9:39 am

    “Regardless, the climate in one point is not the global climate. The Marcott paper (like an old paper by Mann et al) is notable precisely because they do the hard work of trying to get a global picture. You can’t refute their results by saying that in one location the results are different.”

    What? A global picture? Eighty percent of their proxies are marine. Oceans are rife with changes that are peculiar to oceans. Marcott and friends did no empirical research to explore relevant oceanic changes for the purpose of validating their proxies. All of their work was done on models. Will we ever find a paleoclimatologist with instincts for the empirical? I believe that the answer is no.

  17. OssQss says:

    Who funded this ? I want to know if they wasted my tax dollars or $oros money………

  18. MarkW says:

    Anybody who includes tree ring data in any attempt to reconstruct past temperatures, has already indicated that they have no desire to model past climates.

  19. Proud Denier says:

    Both my wife and I reacted the same to the Marcott graph. Obviously it is the proxy data that is flawed.

  20. MarkW says:

    numerobis says:
    March 11, 2013 at 9:39 am

    I’m guessing that you didn’t actually read the article. Dr. Easterbrook gave evidence, with citations as to why the Greenland data accurately mirrors global temperatures.

  21. Matthew R Marler says:

    You have made 2 good points:

    1. The data are measures of marine temperatures;

    2. The reconstruction is different from the reconstruction based on the Greenland ice core data.

    The paper itself is good. I am suspicious of the large upward exclusion at the far right-hand edge of the figure, but I have not yet found any specific reason to distrust it. I have not yet read all of the supporting online material. They present comparisons of the mean temps for different parts of the globe. They computed the uncertainty intervals using bootstrapping, and the infilled missing data using the regularized EM algorithm; and they present the differences that arose among the different methods.

  22. manicbeancounter says:

    Within the paper, is there a list of the proxies, with location and period covered?
    The withdrawn Gergis Australasian temperature at least had such a list the data proxies. A quick look found no proxies on the mainland of Australia, but a number well outside the study area. Also, the further back in time that one went, the smaller the number of proxies.
    The major conclusions of that paper – that the 1990s was the warmest decade of the millenium was the result of the inclusion a coral data set from Palmyra Atoll – over 1300 miles outside the study area and with data that looks decidedly at odds with any other temperature reconstructions.

    http://manicbeancounter.com/?s=gergis

    Steve McIntyre also raised some valid issues on Gergis, that probably apply here as well.
    For him, the proxy selection method was crucially important.

  23. Lance Wallace says:

    Judy Curry has a link to a site that has done some interesting analysis by the blogger “Hank H” that deserves wider notice. He finds using the nine proxies that extend into the 20th century that no hockey stick is visible.

    http://suyts.wordpress.com/2013/03/10/the-hockey-stick-resurrected-by-marcott-et-al-2012/

  24. No matter what the data and no matter what the uncertainty, the solution is always the same: stop the future! Prohibit the use of stored energy in the form of petroleum, coal, and atomic fuels. Revert mankind to the technological status of the dark ages or even the stone ages along with the massive attendant drop in the number of living humans. It is 20,000BC or nothing.

    In any other field, such a thing would be called for what it is: a fraud, a scam, or a religion (as if there is any real difference). Yet our politicians go along with it and we keep voting them into office. It appears that we are doing it to ourselves as we dance as puppets on strings. However, even our puppeteers are puppets dancing on strings. Who then is controlling the strings? No one but the ideas we hold as unquestionable and unquestioned. Shouldn’t we at least ask why?

  25. Paul Matthews says:

    You don’t in fact need to look at any other papers topsee that this paper is nonsense, at least as regards the upward spike at the right hand end. It’s all there in their own graphs. (Matthew Marler you can’t have looked very hard!)

    Look at fig S5 in the Supplementary material (not paywalled, anyone can get this).
    fig S5 shows a reconstruction based on sites near the equator. There’s no hockey stick at all! Similarly S6 shows sites in Norway – again no spike.

    Their sec 6 and fig S10 shows that the number of proxies falls off from the total number of 73 to a very small number, so the spike must be just from a very small number of proxies. Fig S10 also shows that the picture is completely different at different latitudes – at 30-60S for example the temperature shot up 250 yrs ago and then levelled out, while at 60-90S it spikes up then back down again.

    In Sec 7 and fig S12 they test the sensitivity of their result to the choice of ‘time-step’. They claim that ‘some small differences occur’. But you only need to glance at fig S12 to see that this is
    false – the spike is entirely dependent on the choice of the ‘time-step’, and disappears if a larger timestep is used. A first rule of numerical methods is that if this happens your result is meaningless.

  26. NIWA accept that in New Zealand temperatures were much higher for most of the Holocene.

    http://notalotofpeopleknowthat.wordpress.com/2013/03/10/warmer-holocene-confirmed-in-new-zealand/

  27. Bob from the UK says:

    There´s too much evidence that doesn´t fit with the conclusions of Marcott et al. Glaciers in Europe were actually further back in the past than they are now and also there´s ample evidence from the Viking colonisation of Greenland being warmer. Don Easterbrook´s conclusions fit the evidence and there are no contradictions. I remember reading his predictions of cooling quite a long time ago and I´m quite impressed that the climate is responding accordingly. Certainly temperate latitutes in the Northern Hemisphere are experiencing colder winters and if I´m correct the glacial retreat has slowed down. One can see a trend,

  28. john robertson says:

    Timing is self explanatory, AR5.
    Standard IPCC team work, on queue and schedule.
    Grab the headlines, ignore the data and claim perfection.
    Once again, the claims of precedent and certainty, exceed the data.
    If you buy these claims of unprecedented warmth in 70-80% of last 11000 years,as meaningful wrt to global history, I have some Unicorn fence you really must have.

  29. Caleb says:

    I find it remarkable that this “A Reconstruction of Regional and Global Temperature for the Past 11,300 Years” by Shakeum Bakeum Mix (or whomever) gets such acclaim and even adoration, without much thought whatsoever. It seems painfully obvious to me that, if your so-called “science” comes up with the politically correct result, then everyone will smile and nod.

    How is it Truth has taken on the appearances of a spoil sport and party pooper who the “in crowd” does not want around?

    In comparison, voices such as Dr. Don J. Easterbrook’s will seem harsh. You cannot be agreeable when you do not agree. However Truth must be spoken.

  30. DayHay says:

    numerobis
    March 11, 2013 at 9:39 am

    Please see below:

    http://wattsupwiththat.com/2009/04/11/making-holocene-spaghetti-sauce-by-proxy/

    However, does GISP2 still apply to Greenland?
    So the study isn’t really accurate for Greenland, but does come up with a “global” number that does correlate somewhere? Which region would that be then?

  31. Paul Matthews says:

    Another thing to look at is the numbers in the excel file that you can get as part of the supplementary info (database S1)

    http://www.sciencemag.org/content/339/6124/1198/suppl/DC1

    The first few numbers in their “standard” reconstruction are:
    0.60 -0.10 -0.26 -0.26 -0.19 -0.16 ….
    and these are at 20 year intervals.
    So that impressive looking spike at the right hand end consists of only 1 data point!

  32. Steve McIntyre says:

    Although a list of sources of the data from the 73 sites is provided in an appendix, nowhere is any real data presented,

    This is untrue. Marcott provided a dataset with proxy data as used for the 73 proxies.

    There are many issues with this paper. It is very unhelpful to carelessly make this sort of criticism.

    I’ve looked closely at their data and will be commenting on the article.

  33. Robert of Ottawa says:

    Only 73 sites? Hmm …

  34. Steve McIntyre says:

    The comparison to GISP ignores an essential aspect of the Holocene. Orbital changes impact NH and SH differently and a comparison against a high-latitude NH proxy is hardly decisive.

    Again, there are huge problems and defects with this paper, but this particular criticism is not necessarily a criticism..

    Many of the ocean proxies used by marcott have the distinctive NH high-latitude Holocene Optimum pattern. The issues lie elsewhere.

  35. TomRude says:

    Mosher: if you slam Easterbrook then slam Revkin too “This work is complicated, involving lots of statistical methods in extrapolating from scattered sites to a global picture, which means that there’s abundant uncertainty.” What’s good for the goose should be good for the gander.

  36. Paul Matthews says:

    The next question is, where do these numbers at 20 year intervals come from?
    Looking through the excel file you can see that almost all of the proxies don’t have 20 year resolution. It says in the paper that the average is 120 years.
    You can also see, looking at the proxies, that they don’t have a spike at the end (which we’ve already seen from their own figs 5 and 6).
    I can only see one proxy, Agassiz-Renland, that has 20 year resolution and goes up in the last few points. Somehow they must have skewed their averaging so that this has a huge weighting for its final few points.

    This paper is a classic in climate science, surpassing even Mann’s greatest work.

  37. One admission that Marcott does make is that the LIA was the coldest period of the Holocene.

    And we are surprised we have warmed up a bit since?

  38. Jeff Condon says:

    If anyone has a copy of the pay walled paper, can they please forward it to me at my gmail acocunt- jeffid1@…

    Thanks,
    Jeff

  39. Anthony Watts says:

    @Jeff Condon – check your inbox

  40. Mindert Eiting says:

    Lance Wallace: Thanks for the link. Hank’s diagnosis is that the nine most recent proxies were adapted to Mann’s data. Is that true? I would like to know whether the most recent proxies were selected because of correlations with the surface temperature record.
    Theo Goodwin: If measurements from two sources diverge, one of them may be wrong or both. I have serious doubts about the surface temperature record since 1970. Where this record is used hockey sticks seem to appear as symptoms.

  41. Jimbo says:

    Over and Judith Curry’s there’s another deconstruction underway by Rud Istvan. Here’s a sample.

    …..The paper itself said, “…our temperature stack does not fully resolve variability at periods shorter than 2000 years…”

    Evaluate a 300-year MWP using methods lacking 300 year resolution and voila! The MWP turns into a blip diminished by the colder periods on each side…….

    http://judithcurry.com/2013/03/11/lets-play-hockey-again/

  42. Philip Richens says:

    Paul Matthews mentioned the odd spike in the last data point of the 5×5 reconstruction. Maybe worth adding that this final 0.7K rise is for the period 1920-40, which is in fact where the reconstruction finishes. I’ve also looked at the individual proxy data, and it is not at all obvious to my inexpert eye how how the spike arises – although I imagine that the records may be well-correlated only towards the end of the reconstruction. I’m looking forward to seeing Steve McIntyre’s analysis in due course.

  43. Jeff Norman says:

    Dr. Don,

    Thank you for making the effort. I sincerely hope that your subsequent parts are less superficial and allusionally ad hominen. Personally I would have assumed the individual data sets had been properly calibrated unless specifically demonstrated no to be calibrated. Good luck.

    Numerous people have pointed out the consistency of the reported error margins and the bizarre modern spike in the averaged data. Much to look at.

  44. One of the most damning is:

    6. “Over the coming decades are likely to surpass levels not seen on the planet since before the last ice age.”

    So, the authors of the study turned from attempting science to carnival prognostication. It’s not like the warming hasn’t taken a break over the last 16 years, and that there’s been this whopping .28F increase in global temps from 1990-2012. The report degenerated into alarmism and advocacy.

  45. Theo Goodwin says:

    Judith Curry has a guest post at her site. The following is the conclusion of her comment:

    There doesn’t seem to be anything really new here in terms of our understanding of the Holocene. Mike’s Nature trick seems to be now a standard practice in paleo reconstructions. I personally don’t see how this analysis says anything convincing about climate variability on the time scale of a century.

    I cannot imagine a harsher criticism of the state of paleo reconstructions.

  46. arthurpeacock says:

    Lionell Griffith says:
    March 11, 2013 at 10:55 am

    …a fraud, a scam, or a religion (as if there is any real difference).

    That wasn’t necessary or helpful.

  47. Robin Edwards says:

    What is required is the data file that holds the actual numbers from which their graphics were derived. Experience (and I hope common sense) tells me that one should trust nothing in the bizarre world of climatography until you have accessed the data (numbers) that lie behind the often fancy graphics. Thus, I really want to see the data for the last 200 years in numerical format. Only then can I make a considered judgement regarding the current rate of temperature change, or even the current temperature as put forward by the authors. Paywalls don’t help, do they?

  48. robinedwards36 says:

    Minutes later! Now I see that the data are available. Good! The authors seem to very forthcoming in providing links and suggesting (to me) some Google search terms. I like that.

  49. RomanM says:

    Lance Wallace (@ March 11, 2013 at 10:40 am:

    Only 25 of the 73 proxies actually have any data into the 20th century, and none of those shows a hockey stick shape either.

    The hockey stick is created by randomly varying the proxy temperatures and their estimated dates and then interpolating into 20 year intervals. This is done 1000 times for each proxy thus creating 1000 new sets of data. These are each anomalised with a base of their mean for the years 4500-5500 BP where all of the proxies have some observations. There is also some sort of infillling of proxies as well, but I haven’t looked into that yet.

    These results are averaged using some sort of area weighting.

  50. Theo Goodwin says:

    Mindert Eiting says:
    March 11, 2013 at 11:59 am

    “Theo Goodwin: If measurements from two sources diverge, one of them may be wrong or both. I have serious doubts about the surface temperature record since 1970. Where this record is used hockey sticks seem to appear as symptoms.”

    Mindert, Thanks for the shout-out to the lonely empiricist. None of our temperature records, including records of anomalies, are worth the paper they are recorded on. That is, they are worthless if you are interested in factual data rather than trends. Hey, if one is interested in trends only then he should just push ahead, no data is needed.

    We have made a start with the ARGO project but it is just a start. If NSF and other funding agencies were serious they would suspend funding until they convene a balanced committee that can reach decisions on what data collection technologies are needed.

    The genie in the movie Aladdin: Cosmic Power and an itsy-bitsy living space.

    The skeptic in climate science: Cosmic Theory and an itsy-bitsy factual basis.

  51. Given their statement that the LIA was the coldest point in the Holocene, and given some of the large variations in temperatures that we know about over the last 10000 years, it is difficult to see how a degree of warming since can have exceptional in historical terms.

  52. gocats says:

    Well, I looked this over, and just from looking at the graph I have a question: Are there sure they didnt change the scale at the end? IT is pretty clear that prior to the 20th century the graph has been smoothed and averaged in some way, but the only way they could possibly get a spike on a 1 year resolution is if they stopped that smoothing and averaging for the 20th century. How could this possible be valid when they clearly changed their methodology for the last 100+ years in comparison to the previous several thousand years? I am not a statistician or a scientist, but I do consider myself reasonably well educated.

  53. Joseph Murphy says:

    Steve McIntyre says:
    March 11, 2013 at 11:15 am
    I’ve looked closely at their data and will be commenting on the article.

    <<<<<<<<<<<

    Looking forward to it.

    @Mosh – If it is not that complicated for you I would like to here your opinion of it. No /sarc, incase my comment translates that way.

  54. Mosher you are not responding to Dr. Easterbrook, why is that? He seems to make a lot of valid points.

    In general how can “Climate Science” be reported with not one word about accuracy? No description of the level of error, or the precision to which the findings can be trusted? No other science would permit such egregious failure, not even political polling where they always report the percentage within which the results can be trusted. This “Climate Science” is fraudulent, an attempt to manipulate public opinion to keep the funding coming.

    Some day they will all have to wear raincoats in public as all they encounter will spit…..

  55. Hal44 says:

    Thank God for the Internet and its rapid response capability. When I first saw Marcott’s Mann-ian graph with the very smooth temperature bands from 1500 (BP) to 2000 (BP), flags went up fast.
    Just a matter of time until Steve McIntyre or John Christie would hopefully chime in with well-reasoned critiques.

  56. A. Scott says:

    Mosher … I agree with the several other comments … please offer your insight as to issues and what you see – clearly you have something worthwhile to contribute. We all benefit if/when you do. Thx.

  57. Kev-in-Uk says:

    Excellent post by Don Easterbrook – it still comes down to the same old thing though – and that is; that a proxy is still only a ballpark indicator at best, and in no way can be directly comparable to actual ‘calibrated’ measurements of the alleged ‘equivalent’ current climate proxy parameter – UNLESS, by some freak of nature, we find a proxy that is only ever affected by just ONE variable/parameter, from a directly comparable and ‘calibratable’ and CURRENTLY measurable equivalent climatic or ‘depositional’ variable/parameter as of ‘today’ – we are really just performing elaborate guesswork?
    To my knowledge, no such proxy exists (but if I’m wrong, perhaps someone can point me to it!) and hence, ALL proxy data needs to be consigned to the ‘POSSIBLE INDICATOR ONLY’ tray!
    Proxies are useful, sure, but in trying to build complex datasets, composed only of compounded proxies, moulded and tortured to extract alleged meaningful results is, to my mind, rather futile……… just my view.

  58. RomanM says:

    The hockey stick comes from the Supplementary Information of the paper:

    Fig. S3: 1000 realizations of the globally stacked time series (colored lines) and the mean (black line). Temperature anomaly is relative to the 4500-5500 yr B.P. mean. The realizations were derived using the Standard method (see below).

    It is formed from the manipulations on the 1000 artificially constructed “realizations”. No real proxies were harmed in the making of this hockey stick. :)

  59. AndyG55 says:

    Given that they are essentially measuring mostly sea temperatures it may be a reasonable constrcution over the long period. There is a LOT of water to provide buffering/smoothing effects !
    So long as you ignore the fake instrumental atmospheric spike at the far right, you can see that the current temperature is well below the rest of the Holocene.

    Its that fake spike at the end that is their “money” shot !

  60. Reich.Eschhaus says:

    Strange that so many comments on a self-proclaimed skeptical blog fail to see the obvious error…

    In Fig.1 the author adds .7º C to the Greenland temperature proxy data to show the readers where we are today. As a justification for using the Greenland data as a mirror for global temperatures the author points at the correlation between Greenland temperatures and global temperatures and illustrates this with Fig. 2. However, taking the data in the figures and the correlation for granted, the global temperatures have risen by .7º C whereas the the Greenland temperatures have risen by around 3º C in Fig. 2 during the same period! Thus, the correlation appears to be there, but the rise in Greenland is about 4 times or more stronger (hard to say exactly because the graphs have different endpoints). So, instead of adding .7º C to Fig. 1 the author should have added 3º or so. Look where you end up then!

    I can’t understand the author didn’t notice this himself, I really can’t.

  61. knr says:

    AndyG55
    The spike at the end is the entire point of the paper , by doing this they know it will make AR5 and receive much ‘Team’ support along with becoming part of AGW dogma. Its actual validity has nothing to do with this , this is after all ‘climate science’ where quality is a direct function of the support it offers to ‘the cause ‘

  62. rogerknights says:

    Critiques should also take note of proxy studies that were omitted. This omission would be a subtle way of putting their thumb on the scale.

  63. Matthew R Marler says:

    Paul Mathews, you are right, and I had not looked hard. you wrote: Their sec 6 and fig S10 shows that the number of proxies falls off from the total number of 73 to a very small number, so the spike must be just from a very small number of proxies. Fig S10 also shows that the picture is completely different at different latitudes – at 30-60S for example the temperature shot up 250 yrs ago and then levelled out, while at 60-90S it spikes up then back down again.

    That some places show the right-hand spike and some don’t is something I think is to be expected, and subdividing the sample into those series that spike recently and those that don’t may be informative. On the other hand, such post hoc subsample analysis has a multiplicity problem: you can always divide the sample into some series that have “more” of something and the others that have “less”, and with enough covariates you can easily find at least one that seems to discriminate the “more” from the “less” (almost) perfectly. Whether the sample is “representative” of the whole is always a problem. If it is, then the mean is adequate, even though every particular sample is different from the mean. That the number of samples drops off for recent dates is the biggest problem, I think. I don’t think they specifically tested for selection bias by examining whether the early temperatures were statistically related to later availability. If you find that, please let me know.

    If the right-hand spike is true, it can be smoothed out and made to disappear by smoothing with data sufficiently far back in time. So I think that your comment about “time step” is two-edged; maybe the spike is an artifact, or maybe it is something real that can be obliterated by a graphical or statistical technique chosen for that purpose.

  64. Manfred says:

    If this has similar results as Mann et al., there should be something wrong with it. Remember, once errors are removed from Mann et al papers, the hockey stick disappears and the medieval warm period reappears.

  65. Chem59 says:

    My problem with this paper is that it does not pass the “eye test”. The blade of the hockey stick in Marcott, et. al., is made up of exactly 2 points; the latest point, centered at 1940 (+0.6°C anomaly), and the next point centered at 1920 (-0.1 anomaly). Connected, they make the dramatic final rise in temperatures. However, when you look at the raw data, a very different picture emerges. Only 9 of the 73 proxies contain data (33 points in all) in each of the last 2 time periods. These 9 proxies should contain all the information required to make the blade. When a slope is calculated in the 1920-1940 time period for each of these 9 proxies, 5 show a negative slope (decreasing temperature), 3 show a positive slope and 1 shows no change. An average slope for the 9 relevant proxies is slightly positive, but nowhere near as dramatic as in Marcott’s plot. Could it be that Marcott’s statistical procedure has greatly overweighted the only 3 proxies with a positive 1920-1940 slope?

    It seems to me that the statistical massaging of the data has greatly exaggerated the slope of the final 2 data points – giving a much distorted account of what the data actually reveals. My experience with statistical modeling over the years has taught me that if your eyes and the stats output are telling you different things, go with your eyes.

  66. RomanM says:

    People are still looking for hockey sticks in the proxies. The “sticks” are simply not there.

    Of the 25 proxies which have any observations after 1900,

    14 have exactly 1 each
    4 have exactly 2 each
    2 have exactly3 each
    1 has exactly 4
    2 have exactly 5 each
    1 has exactly 8
    1 has exactly 10

    and the last two are amazingly flat!

    There are no 20th century hockey sticks in the proxies themselves.

  67. Even if all 73 proxies go all the way through the record ( which they don’t), and all are highly reliable indicators of temperature (which they are not), we have 4 per 10 degrees of latitude, and 2 per hemisphere of that.

    And they really expect us to believe that they can accurately measure what the global temperature was 5000 years ago?

  68. Gary Hladik says:

    “8. Our global temperature reconstruction for the past 1500 years is indistinguishable within uncertainty from the Mann et al. (2) reconstruction.”

    Uh-oh! Did we lose that pesky Medieval Warm Period again?

    Steve McIntyre says (March 11, 2013 at 11:15 am): “I’ve looked closely at their data and will be commenting on the article.”

    Is there another YAD06 in our future?

    http://climateaudit.org/2009/09/30/yamal-the-forest-and-the-trees/

  69. Manfred says:

    Reich.Eschhaus says:
    March 11, 2013 at 2:09 pm
    Strange that so many comments on a self-proclaimed skeptical blog fail to see the obvious error…
    …So, instead of adding .7º C to Fig. 1 the author should have added 3º or so. Look where you end up then!

    —————————————–

    I noticed that too.I think it would be best to compare with the actual measurement from the GIPS2 site.

    “The current decadal average surface temperature (2001–2010) at the GISP2 site is −29.9°C.”

    http://www.australianclimatemadness.com/2012/02/ice-core-data-shows-greenland-warmer-in-the-past/

    I would have additional issues,

    1. Greenland multi year ice and climate may be particularly influenced by black carbon warming and thus no longer representive for global climate.

    2. MCSHANE and WYNER have shown in their paper, that such reconstruction are not able to reproduce sharp run-up in temperature in the 1990s either in-sample or from contiguous holdout blocks, thus casting doubt on their ability to predict such phenomena if in fact they occurred several hundred years ago.

    Then this compares apples with oranges, sharp variation in measured temperature versus low frequency content several hundred years ago, where extrema are flattened by averaging and also different dating errors of different proxies.

  70. Tad says:

    How did this paper get published?

  71. Reich.Eschhaus says:

    “I think it would be best to compare with the actual measurement from the GIPS2 site.

    “The current decadal average surface temperature (2001–2010) at the GISP2 site is −29.9°C.””

    Yes, that is actually another omission from the author. I have not checked the numbers, so taking it at face value again, but if he had used this value then

    “2. “Global mean temperature for the decade 2000–2009 …. are, however, warmer than 82% of the Holocene” ”

    seems right on spot (by means of eye-balling ;) )

    “I would have additional issues,”

    We all have issues! ;) The reason for my original comment was however that the author can’t have it both ways. Showing the data in Fig. 2 that the Greenland temperature record apparently correlates with global temperatures but at an increased rate (4 times I estimated it from looking at the graph) and at the same time adding the global temperature increase to a record of Greenland temperatures to show that in the larger part of the referenced time frame it was warmer. It’s plain silly! His conclusions are not warranted in any way.

    Re: Black carbon and McShane & Wyner. I don’t know. There may be issues with black carbon but no clue what its effects are at the GISP2 site when the snow there is not melted to have black carbon decrease albedo there. The McShane and Wyner article was quite controversial if I remember correctly. Anyway, I was reacting on the on the logic of the piece above the line and there was no explanation there for why Greenland temperature differences are greater than global temperature differences.

  72. Bill Illis says:

    The problem with Greenland temperatures is that they change by 3 to 5 times as much as the global temperature does.

    Here is Greenland vs the estimated Global temperature since the start of the previous interglacial. Important chart for Greenland temperature watchers. -25.0C in Greenland at the last glacial maximum vs just -5.0C for global temperatures?

    Part of the problem is that the Greenland temperature estimates have been derived from an inaccurate borehole thermometry model. This has overstated the change in temperature over time by 2.0 to 2.5 times what really happened.

    Secondly, one of these Greenland ice cores with 5 times the global temperature change, the Agassiz-Renland ice core, forms the basis of the uptick of the blade in Marcott 2013. No other proxy provides for this uptick. Now Agassiz-Renland was certainly warmer in the Holocene than today but its warm Holocene temperatures are overwhelmed with a bunch of random Tex86 and mg/ca temperature proxies in the same period.

  73. john parsons says:

    Tad says:

    “How did this paper get published?”

    Tad, it got published by passing peer review at one of our most respected science journals.

    If Steve McIntyre, or the author of this thread, or any others wish to rebutt the paper’s findings; they should publish a paper showing how the authors have erred.

    Or they can simply proffer one more opinion on a blog. JP

  74. Tom BR says:

    My summary of this paper: Laughable, as it relies solely on propagation of error and statistically inadmissible data. Worse, the future is forecast based on hollow, inaccurate, and invalid conclusions of recent conditions — using nothing but non-comparable proxy data amalgamations. Sheeees ! What a joke.

    The foolishness of the Marcott et al paper forms a textbook-quality basis for how NOT to pursue and present scientific analysis.

    Shaun Marcott should be ashamed of himself.

  75. ferd berple says:

    “Global mean temperature for the decade 2000–2009 …. are, however, warmer than 82% of the Holocene”
    ==============
    Considering the Holocene is at least 10,000 years long , that means that 1800 years were warmer than the past decade. 1800 years were warmer. 1800 years.

    Yet the polar bears didn’t go extinct. Humans didn’t die out. 1800 years were warmer than present and we saw the birth of human civilization during the same time period. The development of agriculture, cities, law, science, medicine. During a time in which 1800 years were warmer than today!!!

    So, where is the problem? Get a grip.

  76. AndyG55 says:

    @knr says:
    AndyG55
    The spike at the end is the entire point of the paper.

    As I said.. the money shot.. the little bit of fakery that keeps the money coming in. :-)

  77. Manfred says:

    Reich.Eschhaus says:
    March 11, 2013 at 5:29 pm
    …“2. “Global mean temperature for the decade 2000–2009 …. are, however, warmer than 82% of the Holocene” ”
    …seems right on spot (by means of eye-balling ;) )…

    —————————————–

    Figure 1 still shows low frequency data averaged over multiple years. Shorter climate variations, particularly due to AMO, would be flattened out there and be invisible. That inflates the current temperature reading in the context of figure 1.

    From the 1940s and 2000s maxima and the minimum in between in Svaalgard’s plot, I would roughly estimate an AMO contribution of approx. 0.7 deg currently.

    So comparing apples with apples, and therefore AMO removed from the current value, I would use a value of around -30.6 deg in figure 1, which is, by the way, close to Easterborrk’s “current temperature” line.

  78. AndyG55 says:

    ps.. My main point was that Gisp2 is a land temperature, so naturally shows up all the warm points quite well (Holocene optimum, Mayan WP, Roman WP, Medieval WP etc.
    This little bit of fakery uses lots of ocean based proxies, so it would be understandable if the warm period were actually smoothed out quite a bit.

    Without their little instrumental land temp tail, it shows the TRUTH , being that we are still WELL BELOW the the average temperature for the whole of the Holocene.

    Seems they may have stumble over the truth, but quickly picked themselves up and carried on as if nothing had happened. Then by putting the fake tail on, have spun it into a CAGW piece of fiction.

  79. ferd berple says:

    Matthew R Marler says:
    March 11, 2013 at 10:36 am
    The paper itself is good.
    ===========
    You failed to note the obvious flaw. They combined data with different frequency resolution, but did not correct for the difference. The result is statistical nonsense all dressed up in a filly dress with plenty of lipstick.

    So what did the authors do? They grafted apples to oranges and called it pears. The blade is high resolution temperature data, while the lower resolution shaft is what we are getting.

  80. Reich.Eschhaus says:

    Manfred says:
    March 11, 2013 at 6:47 pm

    Nothing of that changes anything about the shoddy logic applied above the line.

    You are not trying to change goal posts, are you?

    You came up with -29.9, now you change it (and that’s me thinking I graciously accept the former number, now to be confronted with another number). Bringing up AMO? Who cares? Do you know anything about AMO in paleological record?

    Whataboutery! The article above the line is still lacking in substance….

    p.s. what do you mean with Figure 1? the upper or the lower part?

  81. Martin H. Katchen says:

    Ok Dr. Estabrooks. I get you . I have just one question. If the Medieval Warm Period is warmer than our own and the Eurasian Arctic Sea Route is almost clear for shipping, why don’t we have any evidence for travel to East Asia by the Vikings via the Kara and Laptev Seas and the Yensei and Lena Rivers at the very least? If not all the way around the Bering Strait to Japan? Why no comparable trade and travel between Han China and Europe via Siberian rivers (or Han conquest of Siberia for that matter) during the Roman Warm Period? And if these warm periods did not affect the polar ice cap and the circumpolar region , what is the climatic difference between those warm periods and the one we are living through that is affecting the polar ice pack? Obviously more research is necessary.

  82. RACookPE1978 says:

    The Vikings traded, raided, and established a presence deep into central Russia. Whether they would have gone “up” those rivers you mentioned depends whether there was “anything” to “go viking” INTO those rivers and “get” (plunder, rape, and steal) …… Deep into an uncharted wilderness? No prize at the end? No trade? No prize money except more trees? Why go there?

    Why not raid easier (and warmer!) simpler/richer villages in France, Normandy, Germany, England, Wales, Scotland, Ireland, Newfoundland, etc? There WERE riches and goods to take going west. Nothing to the east.

    The “Spice Road” went south across deserts and mountains to China. When was it running trade? When did the Chinese accept trade, and when did their bureaucrats deny it? You really cannot get from Siberia (across thousands of kilometers of tundra, trees, taiga and mosquito-infested wastelands pulling …. what? There were no roads, no food, no supplies. You want to pull sleds across Siberia, Manchuria, and THEN China just to load them up and pull them back across China, Manchuria, and Siberia just to load them on a open-top rowboat and go back around the Murmansk cargo trip to Norway? ??????

    Our merchant marine WWII didn’t even like that run – and it was 1/4 as far.

  83. John says:

    Six thousand years ago Northern Africa rapidly devolved from a verdant South America like Savannah into what is now the Sahara Desert. This begs the question, what anthropogenic vector caused this to happen?

  84. Ryan says:

    Celebrities stuck in heavy snow here in old England. Has to be one of the longest and coldest winters I can remember.

    Scientists talking about this decade being the hottest in 10,000 years are starting to sound decidedly loony tunes. They are really not doing themselves any favours. Now would be a good time for them to keep quiet until we have another drought or heatwave but they just can’t help themselves. I don’t think anybody is listening to them anymore. People are just starting to ask themselves “what has happened to our society when scientists, politicians, health experts and economists are talking the kind of nonsense that not even a highly suggestible moron could be convinced to believe?”

  85. DirkH says:

    It is scientific misconduct to splice together two measurement series with a factor of 600 difference in frequency resolution. The authors of that study are not fit for publishing scientific work.

    The NYT thinks that this drives a stake through the heart of skepticism. That is so unfathomable stupid one should prohibit them from ever publishing anything again, as they work actively to make the electorate incapable of making rational decisions.

  86. DirkH says:

    Martin H. Katchen says:
    March 11, 2013 at 10:39 pm
    “Ok Dr. Estabrooks. I get you . I have just one question. If the Medieval Warm Period is warmer than our own and the Eurasian Arctic Sea Route ”

    Interesting question but not related to the quality of the bogus study.

  87. johnmarshall says:

    Thanks for the effort. Rubbish is still rubbish however it is dressed.
    We now need to debunk the GHE theory. Easy to do but difficult to get the alarmists to listen.

  88. George says:

    The Holocene is a very short period of time, and 11,300 years is not even all of the Holocene. The last advance of continental glaciation ended, and the ice began to recede, about 18,000 years ago. Over this brief time the globe necessarily warmed, and the period referred to is part of that warming trend. Is this relationship worthy of a “research” paper? It just re-states information known to geologist for well over 100 years.

    Can we please start dealing with significant time spans?

  89. benfrommo says:

    Martin, who in their right mind would want to invade Siberia 1000 years ago?

  90. Hugh K says:

    Caution!!! Pop-culture climate science at work–

    Paper suggests unprecedented global warming – check
    Far-reaching implications of the conclusions in this paper – check
    Nowhere in the paper is any real data presented – check
    Computer-manipulated data – check
    Issue attention grabbing press release replete with alarmism and advocacy – check
    Assassinate character of those that will/would challenge paper – in the works…

    Anything else is irrelevant.

  91. Rob de Vos says:

    I have read the publication, have seen the datasets in the appendix, and can still not imagine how and fro which datasets Marcott et al could destillate the ernormous uptick of temperature during the last 150 years. Nullius in Verba has posted 3 graphs on this blog that go without saying. See his graphs at http://www.klimaatgek.nl. Can anyone inform me about the uptick at the end? Is it a copy of Mann’s graph?
    .

  92. phlogiston says:

    Bill Illis has got to the heart of it, only one record, the Greenland Agassiz-Renland borehole with anomaloously wide swings, has the hockey stick up-tick. At the end of the record the number of proxies falls toward zero so such anomalies become dominant. further back, the larger number of proxies smooth out the swings, thus a smooth curve.

    Here is a corresponding thought experiment. Start with a Holocene temperature curve looking like a computer mouse in profile, smooth curve with a maximum 8000 years ago and a smooth declining curve to today. Now make 73 exact copies of this curve. Add random noise to each of these copies, causing them to spike up and down. Then average all 73 together. The result will be a curve not significantly different from the initial curve – the same overall decline to the present.

    However, what we now do is to thin out the number of proxies toward the right hand end of the curve – representing the present time, so that most of the proxies end 50-200 years before present. And up to the latest time point, the number declines further till just one or two are left at the very end.

    Now you will see that the random up and down spikes of the few proxies left at the end of the reconstruction near the present time will cause much wider fluctuation at the end of the curve. This is a simple result of a catastrophic fall off in signal to noise at the end of the curve. With a 50% chance, you will get an upspike which can be trumpeted as a hockey stick.

  93. Ulric Lyons says:

    I think there is another cold period that is not expressed well in the Greenland series. Tracking back from the 8.2kyr event by 4627yrs was the start of the Younger Dryas, another 4627yrs back is the start of the Older Dryas. While 4627yrs forward from -8.2kyrs is ~3570 BP, there is a lot of glacial advance going on for a couple centuries either side of this date (1570 BC):

    http://www.geo.arizona.edu/palynology/geos462/holobib.html

  94. Martin H. Katchen says:

    Bemfommo, if the climate was warm enough, Siberia’s Yensei River would offer a quick trip to an ice free Kara Sea which in turn would take a ship to Norway and Britain. Under the right circumstances, Tang China could have been very interested in using that route. So once again, I ask the question: If the Medieval Warm Period or the Roman Warm Period or the Minoan Warm Period were warmer than our own , why did they not affect the Arctic sea ice the way this warm period is affecting Arctic sea ice? Is it because these other periods started from a base of more glacieated land to begin with the way the warming periods that initially ended the ice ages did? Or does CO2 driven warming affect the Jet Streamthat isolates polar air from warmer air differently than Mihailovich Cycle (Northern hemisphere winter at perihekion) warming does? Obviously, these are questions that Mann has not brought up, but I’m mentioning them because as the drawbacks in Mann’s hypothesis become apparent, the alarmists are going to raise these questions and we will need to have the answers to them before the alarmists do.

  95. Martin H. Katchen says:

    Also, as of 4 days ago, in C3 Science, a Russian study from Kamchatka reported through the study of chromatids that the Medieval Warm Period was 1-s degrees warmer than our modern temps of -13 C (in Kamchatka) and a maximum of 3.8 degrees higher than -13 degrees C according to Larissa Nazarova et. al Quaternary Science Reviews 2013.

  96. Lia, trying not be be chilled green on Saint Pat's Day in Toronto says:

    The Marcott paper is worth the read. However, the claim by the journal Science that publications there are more valid than publications here because they are “peer reviewed” falls apart with this review and post by Dr. Easterbrook who is clearly a qualified “peer” who finds valid fault. Science journal apparently cherry picks its so-called peers. Further, the Marcott paper falls apart not just scientifically but also through legal logic — to win a legal argument it is quite valid for lawyers to “argue in the alternative,” so allow me, if you will, to quickly make two points in that line:

    1) Scientifically, Easterbrook debunks scientist Marcott’s methods, but if Marcott’s trend plots are still possibly right accidentally rather than scientifically, then we move to argument 2:

    2) Accept Marcott’s claim that global temperatures naturally fell for thousands of years to and through the human-killing farm-killing “Little Ice Age” that finally reversed around 1850. Then, aren’t we collectively darn glad that the natural trend toward a new genocidal glacial advance finally stopped 160 years ago? If humans indeed helped warm our home planet they kept it out of protracted cold storage, and they should be praised for doing so — they saved it, they saved you, they saved the forebears of both Marcott and Easterbrook,

    Anyway you look at it Marcott should be glad he was not rolled into a snowman with leafless stick ears, eyes of coal and a carrot nose. Easterbrook did that metaphorically; it warmed my heart.

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