Skip to comments.Broken Hockey Stick! (Global Warming Scam Busted)
Posted on 10/29/2003 10:15:44 AM PST by Dan Evans
In a stunning scientific paper just published in Energy and Environment, the infamous `Hockey Stick' as developed by Mann, Bradley and Hughes in 1998 has been comprehensively discredited - using the same data sources and even methodology used by the Hockey Stick's original authors.
According to McIntyre and McKitrick [Energy & Environment ref];
" The data set of proxies of past climate used in Mann, Bradley and Hughes (1998, MBH98 hereafter) for the estimation of temperatures from 1400 to 1980 contains collation errors, unjustifiable truncation or extrapolation of source data, obsolete data, geographical location errors, incorrect calculation of principal components and other
On this website, the Hockey Stick's conclusions about past climates were challenged (see `The Hockey Stick: A New Low in Climate Science') on the basis of direct comparison with numerous other scientific studies which found that late 20th century climate was in no way remarkable when compared with previous `pre-greenhouse' centuries, especially the warmer Medieval period.
However, McIntyre and McKitrick have challenged the `Hockey Stick' on its own turf by subjecting it to an `audit, using the same data and assumptions, and developing a temperature reconstruction from similar principles. It was a classic replication exercise, so necessary in science. The result is shown below -
The McIntyre-McKitrick reconstruction (blue) shows earlier climates to be warmer than the late 20th century, a conclusion supported by numerous other scientific studies, whereas the `Hockey Stick denies this reality. It seems that through a combination of tabulation errors, truncating data series for no valid reason, and `bridging gaps in data with little more than guesses, the `Hockey Stick' authors created a thoroughly false picture of past climates, which was instantly embraced as policy by the UN-IPCC and the greenhouse industry it leads. It became influential in convincing pro-Green policy-makers like former US vice-president Al Gore, that late 20th century climatic warmth was without precedent in human history.
Not only did the `Hockey Stick' fly in the face of a mountain of evidence from other sciences which contradicts its conclusions, but thanks to McIntyre and McKitrick, we now know that the Hockey Stick is internally flawed as well, since its own data sources, properly read, do not support its conclusions either.
This raises the question of the scientific bona fides of climate science itself. McIntyre and McKitrick have exposed fundamental scientific flaws in an influential scientific paper which was fully peer reviewed by `experts' from the greenhouse industry and published in a top journal. Their audit of the databases and statistical processes which lay behind the `Hockey Stick called for first-order statistical skills above all else, and it is here that they have exposed the incompetence which lay behind the original `Hockey Stick' concept. There have been many other instances of deeply flawed science being given an uncritical green light for publication by reviewers from this science, but the question must now be asked whether their pretensions to scientific status can be justified by their performance.
Energy and Environment is one journal that has stood up for free debate on this and other issues of public importance, and is to be commended for publishing this long-awaited and damning critique of the `Hockey Stick'. To facilitate public debate, the journal has taken the unusual step of making the full McIntyre-McKitrick paper freely available online.
But I've seen the junk produced by the creationist crowd by taking selected pieces of fact and extrapolating fiction from it. So I have to take this with a grain of salt.
nice to see John Daly is finding something to keep his mind engaged while going through another round of alcohol rehab.
Sorry, you got the wrong guy;
As you can see, the man you are referring to is 36 years old, blond and is British. The man who wrote this article is older, dark-haired, a little gray around the temples and lives in Tasmania.
I just read the questions posed to Mann & Co. at M&M's site:
http://www.uoguelph.ca/~rmckitri/research/trc.html and it doesn't look like he even tries to answer. However, he does try to obfuscate by raising arcane statistical issues. Here a letter from Prof. Fred Singer that is a lot more to the point: Dear All
There is an additional point I would like to add to Aynsley Kellow's
1. As Knutti/Joos/Stocker correctly point out, the IPCC conclusion, i.e.,
that the 20th century was the warmest in 1000 years, is based on the
instrumental record of surface temperature and NOT on the Mann et al
reconstruction. They should have said "SOLELY based" since Mann et al
stopped in 1980, at which point their temperature did not exceed the
2. Mann et al do not show proxy temperatures beyond 1980. When I
questioned him regarding this matter 3 years ago, he replied by e-mail that
there were no suitable data available. I had found several proxy records
[1-6] that extended well beyond 1980; none showed higher temperatures.
3. I have now examined several dozen more ; again none show higher
4. I conclude therefore that -- contrary to Mann -- many data sets ARE
available; as far as can tell, none agree with the instrumental
SURFACE record; all agree with the satellite and balloon data that show NO
appreciable atmospheric warming trend after 1979.
5. Hence, the IPCC conclusion is not tenable
Best Fred Singer
1. Briffa K.R. 2000.Annual climate variability in the Holocene:
Interpreting the message of ancient trees. Quat. Sci. Rev. 19: 65-73 ;
2. Broecker W. S. 2001. Was the medieval warm period global? Science 291:
3. Dahl-Jensen, D., Mosegaard, K., Gundestrup, N., Clow, G.D., Johnsen,
S.J., Hansen, A.W. and Balling, N. 1998. Past temperatures directly from
the Greenland Ice Sheet. Science 282: 268-271;
4. Jacoby et al 1996 Mongolian tree rings and 20th century warming, Science
273: 771-773; Jacoby and DArrigo 1997 Proc Natl Acad Sci USA 94: 8351;
5. Naurzbaev, M.M. and Vaganov, E.A. 2000. Variation of early summer and
annual last two millennia inferred from tree rings. J Geophys Res 105:
6. Thompson L. G. et al. 2000. Ice core evidence for climate change in the
tropics. Science 289: 1916, Fig 6B
7. Singer, S.F. 2003. Science 301, 595 .
8. A full account is submitted for publication elsewhere.
and it doesn't look like he even tries to answer. However, he does try to obfuscate by raising arcane statistical issues.
Here a letter from Prof. Fred Singer that is a lot more to the point:
As it is still "early" in the evaluation of this publication the and controversy that it has created (or is in the process of creating), it appears to me that both sides have succeeded in making the issue confusing and with a seeming atmosphere of ignominy. Meaning: they're succeeding in making a major mess out of this.
Mann's been arrogant, and he didn't treat their requests with respect. (Given the attacks he's been subjected to, MAYBE that's expected, but now he's made it worse.) As for McIntyre and McKitrick, it doesn't look to me like they did the amount of checking and double-checking that they should have done before going to the presses with a major announcement of apparent "bad science" on the part of Mann et al. The subsequent editorializing also shows a impatience to influence public opinion without first doing some fact-checking. The NRO piece by Murray includes some material that previous editorials didn't; I think everybody should have waited about two weeks for the scientific community to weigh in before declaring Mann's work unsound. (To be sure, the editorials don't go quite that far, but they sure make a lot of implications.)
OK, moving on: as previously discussed with "neverdem", Mann et al. used the modern instrumental period to calibrate the proxy temperature data. They call 1902-1980 the "training interval". That allows a comparison of the proxy data to the instrumental data. If more recent proxy data are examined, they can't be directly compared because they haven't been calibrated the same way.
And also note that Singer's claim that the satellite data shown no appreciable warming since 1979 is inaccurate. All analyses of MSU and AMSU tropospheric temperature data shown some degree of warming, ranging from about 0.4 C /century to 1.2 C /century. The current "best" trend from the Spencer and Christy analysis is the MSU2LT data, a combination of MSU and AMSU data, that shows a 0.74 C/century trend.
I agree that Mann was uncooperative with McIntyre and McKitrick, and because of that, he will have an uphill battle in the minds of the general public convincing them that his analyses are correct, after the editorial commentaries on the McIntyre and McKitrick paper.
However, given that there are independent analyses of climate proxy data that show the same general patterns as the Mann et al. papers, and which do not show the big peaks that McIntyre and McKitrick derived from the erroneous data set that they analyzed, it's unfortunate that the McIntyre and McKitrick paper as written is in error. They didn't compare their results to other researchers results; they were focused on Mann. They've thus succeeded in doing two things: they've shown that Mann is an arrogant academic that does not wish to descend from his Olympian perch; and two, they've shown the danger of publishing without first checking to see if you've done everything correctly.
But they've won the public-relations battle, so perhaps they've done what they set out to do (put Mann's work in a bad light), whether or not they were ultimately correct or not.
I read that pdf file and what I see is a growing trend, not only in this case but others, to find statistical excuses for adjusting the data set upwards.
The argument with Mann's data analyses is not with the instrumental data record that covers the late 1800s to present. So he's not "adjusting the data upward". The argument is that his data analyses reduced the apparent scope and intensity of the Medieval Warm Period warmth and the Little Ice Age cold. When you look at his results and the results of other groups, it's apparent that both periods are present, but their variability is minimized because global data sets have been created. For example, if you compare Mann's data to Esper's Northern Hemisphere tree-ring data, Esper's data has more variability, which is an expected result.
Now we have two authorities stating that it is bad science (Wegman and Jolliffe), as was obvious to most unbiased scientists from the beginning (that includes M&M).
It is interesting that you were much more open minded and skeptical 5 years ago. What changed?
Intriguing that the quote was about the old M&M paper.
The short answer would be: more data. A longer answer would go into the types of data: a lot of phenological indicators (as I've noted) -- quite a few things in the most recent IPCC report that might have gone unnoticed by those just reading the summary for policymakers -- some pithy comments by Frank Wentz I discovered by accident -- the summer sea ice trend -- and there's more, a lot more. I don't have three hours to write it all down.
I'd be curious to know what you think I was more skeptical about. I've felt that I always was consistent on increasing atmospheric CO2 concentrations causing warming, and hewing to a mid-range (2-3 C) projected global temperature increase by 2100. I credited the hockey stick critics with doing necessary work to address discrepancies in that line of research, while always seeing the paleoclimate research as only contributing to, and not defining, knowledge of how the modern climate is changing. Mann and Co. coming out with another paper that reignites the sound and fury is a distraction, because it creates emphasis on sidebar questions like "was the MWP actually warmer or only just as warm as now?" and "if it warmed up in the past naturally, then there's no proof that the warming now is non-natural, is there?" (Pardon me while I choke.)
As this discussion has progressed, I've become increasingly dismayed by the constant barrage of inaccurate, incorrect, and repetitively reiterated discredited and misunderstood arguments trotted out by the increasingly vocal skeptics, which are accepted credulously by those who view climate change solely as a political issue. My dismay has certainly affected my tone.
In your post above you appear to not have made up your mind and were skeptical about Mann’s claims. Today you just dismissed the MWP with a red herring counterargument and Mann’s continued attempts to localize the MWP to Greenland have gained your tacit approval (is Mann the distraction or Mann’s critics?) Mostly it’s your tone that has change partly from the continued repetition of old arguments, and partly from the hardening of your position in general. You were quite successful in countering Mars is warming and numerous other arguments made countless times. Now you have the impression that the denialists are switching arguments (a claim made over and over on RC), when you are only looking at the Rush Limbaugh arguments. The truth is that the skeptics and the AGW proponents have both stayed more or less consistent over the last decade but their idealogues have varied wildly (Mann’s changes in tactics being a perfect example).
However, given that there are independent analyses of climate proxy data that show the same general patterns as the Mann et al. papers,
The argument is that his data analyses reduced the apparent scope and intensity of the Medieval Warm Period warmth and the Little Ice Age cold.
So was I skeptical about Mann's claims? I guess the central claim then was that this period was the warmest in 1000 (2000?) years, globally. Whether or not I was skeptical at the time (I don't remember how skeptical I was or whether I really concerned myself with that particular claim), I was unsurprised when it turned out that there wasn't very good data allowing any quantitative comparisons going back more than 400 years -- hence you can't say that the MWP was warmer than now or vice versa, you can just say now and then were both clearly warm periods.
So now the question might be posed: what about the most recent paper (i.e., Mann et al. 2008)? If I read Climate Audit correctly -- and I haven't bothered with the new paper -- then there's only a "skillful" reconstruction back to 1500, so any results before that are not "skillful". If that's true, then I would think any direct quantitative comparisons are still kinda stupid.
And I will note, as I know I've done numerous times before, that it's not the actual value of the temperature that's as important as the rate of change. Looking at the paleoclimate record solely as an indicator of when abrupt climate changes happened and not concentrating on absolute temperatures, it is clear that times of maximum ecosystem disruption occurred at the times of most rapid climate change. (Unsurprising.) Knowing what I purport to know (and what I think I know) about the current climate indicates that we are on the verge of a very rapid climate change. And I know what that means for ecosystems.
So what about Mann? In summary, he got hired to do a job. He's doing that job by continuing to publish in the field that the university which hired him expected him to publish in. Unfortunately, the controversy that has dogged his earlier efforts has made him a lightning rod, and any further criticism that sticks (and some of it might) will serve as a further example to those who are aleardy convinced of it that the whole scientific understanding of global warming is unsound.
And since I know that's utterly idiotic, there's no point in my pursuing the arcania of centered or non-centered PCA. This is a sideshow. The main show is going on under the big tent.
It's not just arcania of centered or non-centered PCA. It's Briffa's Yamal series Think we'll see corrections to the dozens of papers using the series?
In red above subset of data used to create the hockey stick used as part of dozens of other hockey stick papers. In black, the full set of data known to the researcher.
Environmentalist lies ping!
You must have creationists confused with evolutionists:
- Piltdown man.
- Nebraska man.
- Feathered chinese dinosaurs.
You psuedo-science groupies will stop at nothing!
The confusion is in your mind, as usual.
Have you ever seen a global warming fraud that you didn’t love?
The site is blocking down-loads.
It has to be something a drama queen would love.
It has to give liberals power to force middle class citizens.
It must cause the United States to give extra money to Africa.
And it has to give power to democrats and the so-called "intellectuals" on college campuses...
Pandemic = complete government control/police state
For liberals this has to be something that's mildly plausible - enough to trick most of the people for a while. And long term. It has to be costly and have enough buildup time for Hollywood idiots to jump on the bandwagon and do "fund raisers"...
A pandemic's too quick.
Lol, the phony enviro-wackos were caught lying? What a surprise!
I'm not aware that I'm in love with any global warming frauds. If you're going to call something a fraud, you'll have to justify what and why.
Yes, if they are necessary. Now, the reason I say yes is that the large-scale process of scientific peer-review, i.e., publishing new analyses, is ponderously self-correcting. If the time-series was used (or constructed) erroneously, and this bears out under scrutiny, then there will be new analyses that update and improve the old incorrect analyses.
Be that as it may, McIntyre has a specialty. I think he's doing a good job of keeping the practitioners on their toes and accelerating some necessary introspection. If he's finding errors that need to be corrected, I hope to h*ll they are corrected, ASAP.
Quoting Robert Procter: "The tobacco industry started responding particularly in the 1950s with propaganda. Thats when they started their doubt campaignthe manufacturing of doubt, the manufacturing of ignorance. It was really rather new, certainly on the scale at which they pursued it. It was a new way of using science as an instrument of deception. And thats become important recently. Franchised down into the global warming issue are the same techniques. Demanding ever-greater precision, invoking doubt, questioning the physical methods. Raising alternate possibilities. The whole realm of smoke screens and distractions."
Now, I am not quoting Procter to indicate that legitimate scientific concerns about data accuracy, interpretational bias, methodological misapplication, experimental cross-checking, instrumental calibration (et cetera, et cetera, et cetera) should not be entertained. They should be; and as I said, science is ponderously self-correcting, it takes time to move a heavy weight if a heavy weight needs to be moved. What I am saying is that the "throw everything against the wall without applying cognitive or quality filters to see if anything sticks", just to create a perception of doubt, IS disreputable.
By George! I think you’ve gotit!!!
Good statement. As I see it, there are three issues that need to be resolved. The first was the subject of this thread, the statistics that included an approx 1900 center for PCA causing the effect that any set of red noise time series would produce a hockey stick. I think that has been beaten to death. Second is the whether the data represents temperature. I think the key is that the ability of proxies to represent temperature is not a constant. Third is public access to all the data. There was data that was ignored and data that was discarded, but all of it needs to be made available.
This is just “Saul Alinsky” tactics applied to scientific data. A great deal of bogus or unsubstantiated “data” is dumped in with a few smidgens of real factual evidence, then the entire mix is “weighed” statistically, with the outcome already concluded, then plugging in the “data” to extrapolate BACKWARDS from that conclusion.
It looks almost like good solid work.
Until the foundations of a lot of the “data” is examined.
One biggie that is missed, is the peculiar nature of the very common substance, water, which can exist as a solid, a liquid and a gas, simultaneously, with each state having very different characteristics. When changing from one state to another, HUGE amounts of heat energy are either gained or lost, which is a factor insufficiently considered in terms of rate of heat changes.
In order to change into ice, a LOT of heat has to be lost. Conversely, to melt ice to become water, requires an equal amount of heat to be put back INTO the mass of water molecules. To change from water to water vapor, an even greater amount, some nine times as much as needed to change ice to water, for a given mass of water molecules, is needed to effect that change.
The heat absorbed is from the sun. The heat lost is radiated out to space during the hours when that face of the earth is turned away from sunlight. There is an almost even amount of heat lost at night as there is heat received during the day, on a day-to-day basis. But small increments of gain or loss are cumulative over time, resulting in global warming or cooling. NEITHER CONDITON IS FATAL. Most life here on earth adjusts nicely.
No, he died several years ago.
Outstanding post. Thank you.
Are they going to go back and correct the truncation of Briffa's reconstruction at 1960? Is Briffa going to explain what he meant by
"For the record, I do believe that the proxy data do show unusually warm conditions in recent decades. I am not sure that this unusual warming is so clear in the summer responsive data. I believe that the recent warmth was probably matched about 1000 years ago. I do not believe that global mean annual temperatures have simply cooled progressively over thousands of years as Mike appears to and I contend that that there is strong evidence for major changes in climate over the Holocene (not Milankovich) that require explanation and that could represent part of the current or future background variability of our climate. (Briffa, Sep 22, 1999, 0938031546.txt)"http://climateaudit.org/2009/12/10/ipcc-and-the-trick/#more-9483
Simple question: is truncating Briffa's reconstruction at 1960 propaganda (albeit a small example) or not? No need for a PhD in paleoclimatology, just read the emails and give your answer.
It would be propaganda to depict global temperatures over the 20th century without indicating that there was a change in the methodology used around 1960. I haven't seen examples of that. Usually the instrumental record is clearly delineated.
As for Briffa, I don't know if he'll further explain what he said in the quote you provided. I like what he says at the end. Proving the first part of the statement, however, is different than proving the second part of the statement.
“I haven’t devoted a lot of intellectual resources into trying to understand why the divergence problem happens, I only know that it means that the tree ring methodology for correlation with temperature stops working around 1960.”
If they have just cause to believe the correlation doesn’t work from 1960-2009, then how can we be confident the method DID work for 1000 AD?
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