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.
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