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I caution against imputing malfeasance at this point and suggest softening the following sentence:

"The 12 trees were certainly not selected at random, and the data from these trees do not match data from many, many similar trees that were excluded from the study."

As I understand it, if Briffa does not have very solid scientific reasons for the construction of his series the majority of evidence for "unprecedented" warming in our time will be invalidated.

That fact should be broadcast far and wide, but only after the proper period of response and review. There may yet turn out to be justification for the Briffa/Yamal constructions. All of these revelations are very recent. For now I think it best to err on the side of caution.

However, there can be no justification for withholding data and obstructing the efforts of others to validate these constructions. This is an area where you can shine a harsh and bright light. It is time publications like Nature and Science begin to hold their authors accountable for honest and transparent process. It is time that the political process recognizes that proper scientific publication process has not been enforced in this extremely important area of climatology.

that and $3 will buy you a latte.


It seems difficult to imagine any valid, scientific reasons to justify the exclusion of the many trees which predominantly showed the opposite trend. This cannot have been accidental. If the authors wanted only a small sample size for recent trees to match the small sample sizes of much older trees (for statistical balance), then they could have sub-sampled 12 trees from all of the recent tree samples, so long as they also provided information about the variance of all trees in value and direction.

The hockey stick was the iconic figure in Al Gore's movie, used repeatedly in the IPCC 3rd report and is used in the latest UN report (albeit eggaggerated and credited as Hanno 2009) as well as in the Australian report justifying their ETS. Already touted as the most discredited study in modern history, the hockey stick has become an embarrassment to real science. If a satisfactory explanation is not forthcoming, the scientists involved deserve a very public punishment. Given that this figure really started all the hysteria of global warming, these revelations are explosive. Their withholding of data, aided by the journals, is inexcuseable.

I don't have a suggestion specifically about what you've written but one of the best layman language descriptions of the Hockey Stick debate was written by a British Journalist, Bishop Hill. I never fully understood the all the arguements that McIntyre-McKintric made with respect to the hockey stick issues until Hill laid it out. The Hill story is convincing without these new revelations that the Hockey Stick was nothing but a statistically designed club to beat the fence sitters into submission to the warmist story. If it turns out that the authors were hiding data that contradicted the data presented, the actions of this group sinks to a new level. A good scientist should be the harshest judge of his own hypothesis. Heaven knows other good scientists will put it to the test, that's what they are trained to do. The new archived raw data may indicate that the hockey team had the data all along that disprooved their conclusions. If a judge found a prosecutor had withheld strong exculptory evidence, what do you think he would do?

Schweingruber is a person, not a kind of tree - Fritz Schweingruber, from Switzerland.

Thanks Sean for the kind words.

More comments for TF:
There is a nuance to the bit about the Royal Society. The journal in question (Phil Trans Roy Soc B) has a policy that data should be archived before publication. The data was used in Briffa's paper in 2008, but the journal didn't enforce the policy at the time. When McIntyre wrote to ask them for the data, they agreed to enforce the policy retrospectively.

Whether Yamal is weighted or not depends on the methodology of the particular study it is used in, and it is used in many.

The bit about choosing data that matches the instrumental records is wrong, although climatologists may argue otherwise. You can't "peek" at the data beforehand to see if it matches the instrumental records. It's not a valid technique. If you take a bunch of red noise (i.e. random) series, select all those with twentieth century upticks and add them together, you get a hockey stick because the ups and downs cancel in the early sections, but there are only ups in the twentieth century. You therefore have to choose trees that should respond to temperature because of their location (northern treeline, upper treeline on mountains) and use those, without looking to see what shape they have.


You've done 2 very good things here: 1) You come across as very fair and non-judgmental towards those responsible for the selective data use, and 3) you've done a brilliant job of explaining all the heavy science-speak to laypeople. Heck, I have a formal science education (in Chemistry) and I still have a tough time fully understanding McIntyre's writings.

>No. According to McIntyre there are a total of 252 data series in the Yamal set. The '12' figure refers only to those with data extending to 1988 or later... the cores taken from trees which were still alive. These are Russian Larch trees so, if we assume they took samples from the oldest trees they could find, we're probably looking at values going back to about 1800, not 1000.

The Kaufmann 09 paper has data for proxy number 22 going back to year 5, and this appears to be Yamal.

>Which is, to me, a rather central point because... there actually WAS a dramatic temperature rise over the past 30 years. Known fact. No proxies required. So... if we take everything McIntyre says as 100% valid what we've got is that throwing in this other data he says should be included... yields a result (no recent warming) we KNOW to be wrong. Think on that. His stated objection is that they >didn't< add incorrect data into their study.

And this is the central issue not just of this report, but of every hockey stick paper ever made.
Keep in mind, you are not looking at thermometers here. You are looking at trees, or other biological indicators. It is not known for certain that these trees are indicators of temperature. If you look at 12 samples, and say that they show warming, when you have a larger sample that does not show warming, how can the results be used? You are saying these 12 trees are good thermometers, but those are not. Why? Because the answers matched up. It could be that they are matched up by random chance, and these trees do not tell us anything about temperature in the past, for which we do not have a temperature record to check against.

The studies themselves have the same problem, in that they filter out proxies like Yamal, while throwing out the ones that don't show 20th century warming.

>including Michael Mann's famous hockey stick chart.

The original hockey stick chart doesn't use the Yamal proxy.
It has many other problems, incluing the use of strip-bark and decentered PCA.

>The data, which the scientists had refused to release for a decade, came to light when the Royal Society of London demanded they archive their findings before publishing their latest paper.

I'm not sure if it's the Royal Society of London. THey appear to just call themselves The Royal Society, and it is for the UK and the Commonwealth.
A quibble, but the paper in question was published in 2008. They did not archive until McIntyre notified the journal Phil Trans Roy Soc after publication that they were in violation of policy. McIntyre tried this with Science in 2006 and they said the authors referred to the original paper so they didn't have to archive. The data was put up sometime in the last 6 months, probably Sept 8 or 9.

>Because the data from the Yamal series is weighted, which just means it is given more numerical importance than some other data, changes in Yamal have a disproportionate effect on all the research conducted by this team of scientists, going back to 1998.

This depends on the study and the type of math used. I would drop the word weighted which has a specific math meaning, and just say its use creates a hockey stick shape in averages because of its 20th century high values. Also Briffa's Yamal was published in 2000, and McIntyre lists the earliest use of it in a climate reconstruction as Mann and Jones 2003, and the original Briffa 2000.

>If McIntyre's criticism holds up, it will also have a follow-on effect on many other scientific publications that have referenced this work.

OK, but there is no chance of a retraction of other papers. McIntyre has not highlighted a math error.

>When it is replaced by data from a set of trees called Schweingruber, one can see the difference with the naked eye

Schweingruber is the name of the scientist. He produced many series.
This one is Khadyta River, with an id called russ035w.

>So this may be the reason they only selected 12 trees out of hundreds available to measure.

I think it's worse than this. They measured more and only selected these 12.

>The chart and the methods used to produce it were actually investigated by a Congressional Committee, which found that Mann et al had made serious errors and that their conclusions were not warranted.

It wasn't the Committee that did the investigating, but a panel of the National Academy of Science and a panel of statisticians.
Also conclusions not warranted is the opposite of what they concluded. The NAS and I think Wegman as well said that the conclusions were warranted given other studies. Both reports said the methods were not valid.

Briffa is not a RealClimate contributor.

CBD, the way they get data going way back is that at any point in time, only some of the samples are alive. You would like to get a large number for each time period, to balance out other factors. For example, if a neighbor tree dies, a tree will grow more because of more sunlight, nutrients, etc. That is the issue with Yamal.
Also, another pair of scientists processed the same Yamal data, and came up with a different shape, that does not have the same hockey stick shape.

CBD, the same author Briffa developed a series in 1995 called the Polar Urals. This was found to have many problems, specifically it only had 3 trees for some time periods, and they updated it later with more tree samples. When they updated, they found medieval temperatures to be higher than modern times. This proxy was then not used by Briffa and instead he used the Yamal proxy which showed warmer modern times than medieval. So there he selected the proxy he would use.

The accusation is that he only used some trees to get an extreme hockey stick shape.

The publication was "Transactions of the Royal Society B" - "B" for 'biology".

For US audiences, I would write " 'Transactions of the Royal Society' (of Science)", for clarity. Newton was a member. But laymen do not know unless they are science geeks who reference published lit.

MikeN Has done a pretty thorough job and pretty much hit anything I would have said and more. I would like to point out that from what I've seen on CA and AV McIntyre has a VERY solid case for claiming that Briffa has Cherry Picked his data to come to a predetermined outcome. On top of that, since 2000 there are a number of papers that use the Yamal data, and for whatever reason, use the same weighting methods.
From what I've read, I see NO REASON to weight the Yamal 12 cores as significantly as has been done while compelling CONTRADICTING evidence exists and is widely known. Unfortuneately, this kind of malarky is part-n-parcel with certain "Professional Alarmists". (I sometime hesitate to call them Scientists as their methodsand actions fly in the face of ethical scientific principals.)

As to CBD's logic that there was a temp spike for 30 years as FACT, and anything contradicting it should be thrown out... well, considering Watts' work at Surfacestations.com and the known FACT that data collecting methods outside of the us leave a considerable amount to be desired (IE: Phil Jones and the dog who ate his CRU archives, The russian Sept/Oct mixup where the temp data from the preceeding month was carbon copied to the next month and turned in as actual temps, and the 1990 global rural station droput coinciding with a spike in global temp that same year.)... well, I wouldn't go so far as to say that the 30 temp spike is FACT, concidering we aren't really sure how much of the global temp rise is ARTIFACT from poor data gathering, station dropout, and UHI.
Let's not be so hasty to be throwing out contradicting data, ust because we don't like it. We'd be making the same mistake as Mann, Briffa, Etc...


MikeN is misleading on a crucial point:

" The NAS and I think Wegman as well said that the conclusions were warranted given other studies. Both reports said the methods were not valid."

"...the conclusions were warranted given other studies"??? The Wegman said no such thing. His report, unlike the NAS one chaired by Texas A&M pprof Gerald North, did not mince words that could be misinterpreted.

"While the work of Michael Mann and colleagues presents what appears to be
compelling evidence of global temperature change, the criticisms of McIntyre
and McKitrick … are indeed valid. ..

"I am baffled by the claim that the incorrect method doesn’t matter because
the answer is correct anyway. Method Wrong + Answer Correct = Bad

(Wegman, E., 2006. Response of Dr. Edward Wegman to Questions Posed by the
Honorable Bart Stupak . Available at:

The NAS report is more muddled, since the conclusion wrote that Mann's inferences were a "plausible" interpretation, even if they could not uphold it - eg, early data for the last one-thousand years was too sparse.

This got entirely F****d UP by the media as Christopher Horner documented in his "Politically Incorrect Guide to Global Warming" (see end of chapter 5 or 6). Therein, you will see how CNN and the Boston Globe reported that global warming was even more certain because of the NAS report!

Of course, Mann had spome-time collaborators on the NAS committee since denrdo and paleoclimatrology is a small field and the politics of the matter necessitated such "balance." Chairman Gerald North indicated "we just winged it," conducting no quality checks of their own. Thus, the conclusions were softened. However, the internals of the report fully uphold M&M.

Having seen North lecture after the IPCC was awarded the Nobel Peace Prize, one wonders how he could have said (to Congressional Committee-perhaps Joe Barton or Imhofe) when asked about Wegman, North said his committee was in essential agreement with Wegman's report.

I believe North simply didn't read it, or at least not in much depth. He could not, have said the above, if he did.

As his lecture showed, North upheld the IPCC AGW dogma. But with the second breaking of the Hockey Stick, one wonders if he might rethink the claim that it was independently supported. This was his claim when I asked him about it after he standard IPCC lecture to a packed house at the University of Colorado at Boulder, November 2007.


I think you misinterpret what MikeN was saying. He seems to me to be saying that McINTYRES points were validated by BOTH Wegman, and North.

One last thing about the thermometers. If they cherry-picked ones that matched current temperatures, and we know that trees that are good thermometers now are good ones in the past, then this is an OK method. A problem with this study is that the trees do not live very long. So by throwing out the trees that are bad thermometers in the current period, you now have a mix of good and bad trees for the year 1200, while in current times you have all good trees. So now you can't compare the two periods.
I think additional discussion should go to the examiner article which is posted.

Have you looked at Huybers, comment on ``Hockey sticks, principal components, and spurious significance'' by McIntyre and McKitrick [2005], Geophysical Research Letters, 2005. Its on his Harard website. He agrees there are errors and then says McIntyre made errors of his own, very subtle one. http://www.people.fas.harvard.edu/~phuybers

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