From the Telegraph:
The ‘hockey stick’ that became emblematic of the threat posed by climate change exaggerated the rise in temperature because it was created using ‘inappropriate’ methods, according to the head of the Royal Statistical Society.
By Louise Gray, Environment Correspondent
Professor David Hand said that the research – led by US scientist Michael Mann – would have shown less dramatic results if more reliable techniques had been used to analyse the data.
Prof Hand was among a group of experts charged with investigating the “climategate” email scandal that engulfed the University of East Anglia’s Climatic Research Unit (CRU) last year.
Sceptics claimed that the hacked messages showed scientists were manipulating data to support a theory of man-made global warming.
However the review, led by Lord Oxburgh into the research carried out by the centre, found no evidence of ”deliberate scientific malpractice”.
Lord Oxburgh said the scientists at the research unit arrived at their conclusions ”honestly and sensibly”.
But the reviewers found that the scientists could have used better statistical methods in analysing some of their data, although it was unlikely to have made much difference to their results.
That was not the case with some previous climate change reports, where “inappropriate methods” had exaggerated the global warming phenomenon.
Prof Hand singled out a 1998 paper by Prof Mann of Pennsylvania State University, a constant target for climate change sceptics, as an example of this.
He said the graph, that showed global temperature records going back 1,000 years, was exaggerated – although any reproduction using improved techniques is likely to also show a sharp rise in global warming. He agreed the graph would be more like a field hockey stick than the ice hockey blade it was originally compared to.
“The particular technique they used exaggerated the size of the blade at the end of the hockey stick. Had they used an appropriate technique the size of the blade of the hockey stick would have been smaller,” he said. “The change in temperature is not as great over the 20th century compared to the past as suggested by the Mann paper.”
…
Prof Hand praised the blogger Steve McIntyre of Climate Audit for uncovering the fact that inappropriate methods were used which could produce misleading results.
======================
Complete article here
J.Peden (11:02:00) :
“Briffa’s methods did the same thing via cherry picking the “correct” trees from within a population, in contradiction to why in statistics you analyze a whole population to begin with to see if it correlates with a known measure”.
Briffa’s first selection was limited in numbers. Then came Mcintyre’s selection
also limited in numbers. They contradicted each other. Later, Briffa (et al)
analyzed everything available from Yamal area. I am sorry, but the whole
material was closer to Briffa’s first selection and Mcintyre’s selection was
the anomaly.
The give away is this: “Had they used an appropriate technique the size of the blade of the hockey stick would have been smaller,” So where is this new graph constructed using the “appropriate technique” that has a smaller blade? Well it doesn’t actually exist, Professor Hand is talking nonsense.
JK: From the linked Telegraph article:
Prof Mann, who is Professor of Earth System Science at the Pennsylvania State University, said the statistics used in his graph were correct.
“I would note that our ’98 article was reviewed by the US National Academy of Sciences, the highest scientific authority in the United States, and given a clean bill of health,” he said. “In fact, the statistician on the panel, Peter Bloomfield, a member of the Royal Statistical Society, came to the opposite conclusion of Prof Hand.”
JK: Sorry, Prof, you just lied again. By omission of the fact that the US National Academy of Sciences Wegman report had harsh words for your paper:
JK: The Wegman report was commissioned by congress and done by the National Academy Of Sciences. Wegman is a world renowned statistical expert and former head of the National Academy of Sciences statistics division. Surface Temperature Reconstructions for the Last 2,000 Years – This free PDF was downloaded from: nap.edu/catalog/11676.html )
Wegman Report, item 7, page 49 (MBH is the hockey stick paper): Our committee believes that the assessments that the decade of the 1990s was the hottest decade in a millennium and that 1998 was the hottest year in a millennium cannot be supported by the MBH98/99 analysis.
JK: MBH98/99 are the papers that brought us the hockey stick.
Wegman Report, item 7, page 49: The cycle of Medieval Warm Period and Little Ice Age that was widely recognized in 1990 has disappeared from the MBH98/99 analyses, thus making possible the hottest decade/hottest year claim. However, the methodology of MBH98/99 suppresses this low frequency information. The paucity of data in the more remote past makes the hottest-in-a-millennium claims essentially unverifiable.
Wegman Report, item 6, page 49: Generally speaking, the paleoclimatology community has not recognized the validity of the MM05 papers and has tended dismiss their results as being developed by biased amateurs.
Wegman Report, page 49: 1. In general we found the writing of MBH98 somewhat obscure and incomplete. The fact that MBH98 issued a further clarification in the form of a corrigendum published in Nature (Mann et al. 2004) suggests that these authors made errors and incomplete disclosures in the original version of the paper. This also suggests that the refereeing process was not as thorough as it could have been. . .
Wegman Report, page 49: 2. In general, we find the criticisms by MM03, MM05a and MM05b to be valid and their arguments to be compelling. We were able to reproduce their results and offer both theoretical explanations (Appendix A) and simulations to verify that their observations were correct. . .
JK: MM03, MM05a are the blogger’s papers that exposed the errors. See ClimateAudit.org
Wegman Report, page 49, item 3: . . Because the temperature profile in the 1902-1995 is not similar, because of increasing trend, to the millennium temperature profile, it is not fully appropriate for the calibration and, in fact, leads to the misuse of the principal components analysis. However, the narrative in MBH98 on the surface sounds entirely reasonable on this calibration point, and could easily be missed by someone who is not extensively trained in statistical methodology. Dr. Mann has close ties to both Yale University and Pennsylvania State University. We note in passing that both Yale University and Pennsylvania State University have Departments of Statistics with excellent reputations9. Even though their work has a very significant statistical component, based on their literature citations, there is no evidence that Dr. Mann or any of the other authors in paleoclimatology studies have significant interactions with mainstream statisticians.
Wegman Report, page 49: 8. Although we have not addressed the Bristlecone Pines issue extensively in this report except as one element of the proxy data, there is one point worth
mentioning. Graybill and Idso (1993) specifically sought to show that Bristlecone Pines were CO2 fertilized. Bondi et al. (1999) suggest [Bristlecones] “are not a reliable temperature proxy for the last 150 years. . .
Wegman Report, page 52: Conclusion 4. While the paleoclimate reconstruction has gathered much publicity because it reinforces a policy agenda, it does not provide insight and understanding of the physical mechanisms of climate change except to the extent that tree ring, ice cores and such give physical evidence such as the prevalence of green-house gases. What is needed is deeper understanding of the physical mechanisms of climate change.
Wegman report, page 4: In our further exploration of the social network of authorships in temperature reconstruction, we found that at least 43 authors have direct ties to Dr. Mann by virtue of coauthored papers with him. Our findings from this analysis suggest that authors in the area of paleoclimate studies are closely connected and thus ‘independent studies’ may not be as independent as they might appear on the surface.
Thanks
JK
mikael pihlström (13:23:07),
If you have a problem with a chart, there are a number of ways to handle it.
You can do your own search for the chart’s provenance, like I did. The original, I believe, is from a magazine article, but I can’t recall which one it’s from.
Or, if you think the chart is not accurate, you can draw your own chart, like Michael Mann did.
Or, you can simply disregard the chart and move to another article, since it bothers you so much because it shows what everyone else knows, but lacks the name of the person who converted the data into chart form.
Or, you can stop commenting on this site, which you wrongly disparage as posting unethical charts – screaming it in capital letters.
But please, quit nitpicking everything you think you’ve found, to try and discredit anyone who doesn’t think like you do. That doesn’t work here. You have been told repeatedly that your belief requires evidence to be convincing.
If you want to see a genuine, manipulative fraud, see jim karlock’s post above about Michael Mann. And since you actually seem to believe Keith Briffa, and his peer review pals, and how they manipulate the system, you should certainly read Caspar and the Jesus Paper.
It’s a very easy read. In only a few pages it gives a very revealing picture of the corrupt climate peer review process. Even Michael Mann is featured. It will open the eyes of anyone not blinded by alarmist true belief.
Where did the diagram come from? See McIntyre Climate Audit May 9 2008:
‘Where did IPCC Figure 7c come from?’
It seems to have come primarily from a Lamb publication on the MWP in 1965.
Smokey (15:20:32) : ‘
“Or, if you think the chart is not accurate, you can draw your own chart,”
Whatever you say, however strange to my ears, I can accept as your freedom
of expression. But, this concerns a minimal standard of journalistic
ethics. You know the anonymous graph with two wrong names beneath it is misleading. If I had not read that Prof Hand’s version was referred to as
a field hockey stick (that is it ressembles Mann’s hockey stick more than your
Spagetti stick) i would have been fooled.
Just add some words: Note: the graph is not from the Telegraph/ or D. Hand.
I can’t edit your main page
david elder (15:46:55),
Thank you. Now, would someone please hand mikael a hanky and tell him it’s all better now? Thanx.
bob (09:13:00) :
Has McIntyre shown that the statistical methods did indeed produce different results, rather than could have produced misleading results.
In other words, any evidence that the hockey stick graph is wrong?
Anyway MBH98 is obsolete anyway, and maybe it is time to stop arguing that it is faulty or misleading, as there is better data in more recent publications.
Michael Mann pioneered the use of bad proxies, and others rapidly piled on. Briffa’s stick even uses dead trees that show it was never warm enough for the trees to exist.
I’ve been thinking of an analogy.
Say law enforcement has solid evidence that a body is buried in a field. So they dig 1000 holes and one hole has a body, thus confirming the evidence.
Then, along comes Mann and uses the 999 empty holes to prove that no body was really there after all. Others pile on and viola!!!
Lots of studies showing no body.
Only one study showing there was a body.
Overwhelming evidence!!!!
CRU has a new project; The Dendroclimatic Divergence Phenomenon: reassessment of causes and implications for climate reconstruction. http://www.cru.uea.ac.uk/cru/research/
And who is Principal Investigator? Yes, you guessed it, Briffa.
Quote:
“It suggests that the degree of warmth in certain periods in the past, particularly in medieval times, may be underestimated or at least subject to greater uncertainty than is currently accepted. The lack of a clear overview of this phenomenon and the lack of a generally accepted cause had led some to challenge the current scientific consensus, represented in the 2007 report of the IPCC on the likely unprecedented nature of late 20th century average hemispheric warmth when viewed in the context of proxy evidence (mostly from trees) for the last 1300 years. This project will seek to systematically reassess and quantify the evidence for divergence in many tree-ring data sets around the Northern Hemisphere.”
“Based on recent published and unpublished work by the proposers, it has become apparent that foremost amongst the possible explanations is the need to account for systematic bias potentially inherent in the methods used to build many tree-ring chronologies…”
The project start and end dates are 12/09 – 05/12. Look at the start date. Could this be coincidence?
Who is funding this work?
” mikael pihlström (14:07:36) :
J.Peden (11:02:00) :
“Briffa’s methods did the same thing via cherry picking the “correct” trees from within a population, in contradiction to why in statistics you analyze a whole population to begin with to see if it correlates with a known measure”.
Briffa’s first selection was limited in numbers. Then came Mcintyre’s selection
also limited in numbers. They contradicted each other. Later, Briffa (et al)
analyzed everything available from Yamal area. I am sorry, but the whole
material was closer to Briffa’s first selection and Mcintyre’s selection was
the anomaly.”
Surely it comes down to this. either recently “de-glaciated” topsoil contains vegetable matter that carbon dates to 800-1400 AD or it does not. If it does we can put the hockey stick in the sin bin with the phlogiston, the ether and the indivisible atom. If not then the MWP can go there instead. Stop tweaking the hypothetical models and go get some results, you know, do some science….
JK: Look a little closer. The Wegmen report was not connected to the NAS. The NAS offered to do a study for the House committee, but the Rep leadership said no, and asked Wegman instead. Wegman, a respected statistician who happens to have many connections to the military and defense industry – he was an early supporter of Regan’s SDI program – was critical of Mann. Later the NAS did a politically independent study and supported Mann’s work. Mann also responded to Wegman. The debate is legitimate, but you put the NAS on the wrong side.
Of course the most important point is that Hand said “any reproduction using improved techniques is likely to also show a sharp rise in global warming.” So, you can continue throw spit balls at those nerdy scientists from the back row, or you can get serious and play a constructive roll in figuring out what we can do to avoid or mitigate the major problems climate is very likely going to cause.
Note: I am not affiliated with the deepclimate blog, although I have posted there. Nor am I a statistician.
Obviously, now that the Brits & Scots have whitewashed the CRU component of The TEAM… they are backfilling in blame to anyone they think can handle it.
I would have thought that GB was more mature than this – can’t they just admit that they are all frauds – and should be imprisoned.
Regular readers know that nothing that Mann has done can be substantiated – even Dr. Jones is smart enough to know that he had been caught – and admitted no increase in temps since 1995.
Of course we know that, collectively, The TEAM is responsible for multiple capital crimes against humanity – and should be jailed now.
A case can be made that an extreme diversion of precious economic and scientific resources has transpired – causing loss of life and misery to many.
If you are a cheat and you have been caught – “Mann up” – and take your punishment.
Oh, and please help us find the REAL RAW TEMP DATA – maybe some honest Scientists can then determine if there is really anything going on.
Here is the WUWT link to the battle of the graphs
http://wattsupwiththat.com/2009/07/08/the-medieval-warm-period-linked-to-the-success-of-machu-picchu-inca/
(sorry mod, put it in the wrong article first by mistake)
OT but really very important IMHO.
Does anyone else think the EPA has screwed up again re: CFL’s.
I think disposal kits, fully disclosed instructions and mandatory recycling procedures and facilities should be required as a condition of selling the CFL’s.
These same people brought us MTBE and now we have contaminated ground water all over –
Shall we add Mercury Poisoning to the same ground water?
Or, is this a set up for a recent law school grad?
RockyRoad (10:35:33) :
The latter part of your post took some deciphering. Mainly because you pretty much ignored the heuristics that allow is humans to ignore spelling errors.
1) Usually should start with the right letter, (applies to some extent with end letter).
2) Transpositions should be adjacent
I know there are other factors but these are two of the main ones.
DaveE.
@Jonathan Drake (16:03:08) : “The project start and end dates are 12/09 – 05/12. Look at the start date. Could this be coincidence? … Who is funding this work?”
The funding request, that is the grant proposal, must have been submitted months before the start date. I’m surprised they don’t list the funding agency and the amount. Most scientists like to brag.
JD, I found the funding source: the Natural Environment Research Council. See the bottom of page 3 of the link below.
http://www.nerc.ac.uk/funding/available/researchgrants/awards/2008/standard-december.pdf
Ah, an article by Louise “copy and paste” Gray, Environment Correspondent. Why the heck the Telegraph pay her and Geoffrey Lean is beyond me. Poor people are still in denial!
jim karlock (14:41:34) :
JK: From the linked Telegraph article:
Prof Mann, who is Professor of Earth System Science at the Pennsylvania State University, said the statistics used in his graph were correct.
“I would note that our ‘98 article was reviewed by the US National Academy of Sciences, the highest scientific authority in the United States, and given a clean bill of health,” he said. “In fact, the statistician on the panel, Peter Bloomfield, a member of the Royal Statistical Society, came to the opposite conclusion of Prof Hand.”
JK: Sorry, Prof, you just lied again. By omission of the fact that the US National Academy of Sciences Wegman report had harsh words for your paper……
=====
You are mistaken. You should apologize to Mann for calling him a liar.
Wegman’s report is available online at
http://climateaudit.files.wordpress.com/2007/11/07142006_wegman_report.pdf
It doesn’t say Mann’s Hockey Stick is wrong.
What it does say:
“Overall, our committee believes that Mann’s assessments that the decade of the 1990s was the hottest decade of the millennium and that 1998 was the hottest year of the millennium cannot be supported by his analysis.”
So the Wegman report is saying small parts of the Hockey Stick are not supported by Mann’s analysis. Over the length of the millennium (1,000 years)
the analysis does not support the claim that
1998 was the hottest year or the 1990’s was the hottest decade. Maybe they were, maybe they weren’t.
The National Research Council agreed with Wegman on those two points but but found additional evidence supports Mann’s basic conclusion that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years.
“The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes both additional large-scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators, such as melting on ice caps and the retreat of glaciers around the world, which in many cases appear to be unprecedented during at least the last 2,000 years.”
The National Research Council Report is available at
http://books.nap.edu/openbook.php?record_id=11676&page=3
Wegman on Mann’s Hockey Stick:
“The fact that the answer may have been correct does not justify the use of an incorrect method in the first place.”
Posters interested in the controversy over Mann’s temperature reconstruction,”the hockey-stick curve,” may want to read Richard L. Smith’s report on presentations at an American Statistical Association session titled “What is the Role of Statistics in Public Policy Debates about Climate Change?”
Ed Wegman of George Mason University gave a talk
focusing on the statistical flaws in the Hockey Stick that, in his view, render much of the current literature on this subject of doubtful validity. J. Michael Wallace of the University of Washington presented the broader findings of a NRC panel that acknowledged the statistical issues raised by Wegman, but defended the hockey stick based on a broader scientific context.
“The NRC report reviewed a number of other reconstructions of the temperature record based on proxy observations and believed that the Mann et al. claim that the last two decades were the warmest of the last 1000 years was entirely plausible.”
Wegman’s response was “the fact that the answer may have been correct does not justify the use of an incorrect method in the first place”
or
“Method Wrong + Answer Correct = Bad Science.”
The report is available in a 2007 ASA newsletter at http://www.amstat-online.org/sections/envr/ssenews/ENVR_9_1.pdf
I wonder what Wegman thinks Method Correct + Answer Wrong equals?
Wren (20:06:57),
Your apologies for the shenanigans in Mann’s game playing count for nothing.
If Mann’s Hokey Stick was legit, it would still be used. It’s not.
Smokey (20:12:15) :
Wren (20:06:57),
Your apologies for the shenanigans in Mann’s game playing count for nothing.
If Mann’s Hokey Stick was legit, it would still be used. It’s not.
====
It’s legit, and it’s still used.
“It’s legit, and it’s still used.”
Not in the new UN/IPCC Assessment Reports. Why? Because it’s been debunked.
Explanation here: click