The data for the Briffa et al. version of the hockey stick looks to have been selected to support the IPCC position. This follows a pattern.
Dr. Hansen, GISS leader adjusts their temperature records constantly, disproportionately favouring warming.
NOAA has been accused of omitting unsupportive data.
Both venues are favoured by the IPCC.
Now the Hadley CRU, another IPCC favoured org is under the microscope.
I waited till today to see what sort of defence would be mounted. None so far.
The AGW zombie staked with another hockey stick. Jump to the end for links to the original articles in full.
(Layman's guide to the intrigue link)
Steve McIntyre, nemesis of warmist scientists has uncovered and deduced evidence of either enormous incompetence or outright deception on the parts of the hockey stick team and Climate Research Unit of the Hadley Centre associated with the UK Met. Office. Data used to produce the hockey stick came from that archived by the CRU. That data appears to have been selected from a much larger sample. When all the data is considered, something remarkable comes to light. Warming disappears. This truly remarkable piece of detective work demands at the very least a nobel peace prize, preferably that which the IPCC and Al Gore will be returning.
From Steve's post - Yamal: A "Divergence" Problem link:
Here's a re-cap of this saga that should make clear the stunning importance of what Steve has found. One point of terminology: a tree ring record from a site is called a chronology, and is made up of tree ring records from individual trees at that site. Multiple tree ring series are combined using standard statistical algorithms that involve detrending and averaging (these methods are not at issue in this thread). A good chronology–good enough for research that is–should have at least 10 trees in it, and typically has much more.
1. In a 1995 Nature paper by Briffa, Schweingruber et al., they reported that 1032 was the coldest year of the millennium - right in the middle of the Medieval Warm Period. But the reconstruction depended on 3 short tree ring cores from the Polar Urals whose dating was very problematic. www.climateaudit.org/?p=877.
2. In the 1990s, Schweingruber obtained new Polar Urals data with more securely-dated cores for the MWP. Neither Briffa nor Schweingruber published a new Polar Urals chronology using this data. An updated chronology with this data would have yielded a very different picture, namely a warm medieval era and no anomalous 20th century. Rather than using the updated Polar Urals series, Briffa calculated a new chronology from Yamal - one which had an enormous hockey stick shape. After its publication, in virtually every study, Hockey Team members dropped Polar Urals altogether and substituted Briffa's Yamal series in its place.
www.climateaudit.org/?p=528. PS: The exception to this pattern was Esper et al (Science) 2002, which used the combined Polar Urals data. But Esper refused to provide his data. Steve got it in 2006 after extensive quasi-litigation with Science (over 30 email requests and demands).
3. Subsequently, countless studies appeared from the Team that not only used the Yamal data in place of the Polar Urals, but where Yamal had a critical impact on the relative ranking of the 20th century versus the medieval era.
4. Meanwhile Briffa repeatedly refused to release the Yamal measurement data used inhis calculation despite multiple uses of this series at journals that claimed to require data archiving. E.g. www.climateaudit.org/?p=542
5. Then one day Briffa et al. published a paper in 2008 using the Yamal series, again without archiving it. However they published in a Phil Tran Royal Soc journal which has strict data sharing rules. Steve got on the case. www.climateaudit.org/?p=3266
6. A short time ago, with the help of the journal editors, the data was pried loose and appeared at the CRU web site. www.climateaudit.org/?p=7142
7. It turns out that the late 20th century in the Yamal series has only 10 tree ring chronologies after 1990 (5 after 1995), making it too thin a sample to use (according to conventional rules). But the real problem wasn't that there were only 5-10 late 20th century cores- there must have been a lot more. They were only using a subset of 10 cores as of 1990, but there was no reason to use a small subset. (Had these been randomly selected, this would be a thin sample, but perhaps passable. But it appears that they weren't randomly selected.)
8. Faced with a sample in the Taymir chronology that likely had 3-4 times as many series as the Yamal chronology, Briffa added in data from other researchers' samples taken at the Avam site, some 400 km away. He also used data from the Schweingruber sampling program circa 1990, also taken about 400 km from Taymir. Regardless of the merits or otherwise of pooling samples from such disparate locations, this establishes a precedent where Briffa added a Schweingruber site to provide additional samples. This, incidentally, ramped up the hockey-stickness of the (now Avam-) Taymir chronology.
9. Steve thus looked for data from other samples at or near the Yamal site that could have been used to increase the sample size in the Briffa Yamal chronology. He quickly discovered a large set of 34 Schweingruber samples from living trees. Using these instead of the 12 trees in the Briffa (CRU) group that extend to the present yields Figure 2, showing a complete divergence in the 20th century. Thus the Schweingruber data completely contradicts the CRU series. Bear in mind the close collaboration of Schweingruber and Briffa all this time, and their habit of using one another's data as needed.
10. Combining the CRU and Schweingruber data yields the green line in the 3rd figure above. While it doesn't go down at the end, neither does it go up, and it yields a medieval era warmer than the present, on the standard interpretation. Thus the key ingredient in a lot of the studies that have been invoked to support the Hockey Stick, namely the Briffa Yamal series (red line above) depends on the influence of a thin subsample of post-1990 chronologies and the exclusion of the (much larger) collection of readily-available Schweingruber data for the same area.
Calls for an explanation or resignations have been made. I would go further, I believe that on an issue of such importance, let's face it, the world has been inconvenienced to a huge degree and people have died as a direct result of policies based on the data, the veracity should be tested in court.
Leading UK Climate Scientists Must Explain or Resign link
by Jennifer Marohasy
[...] Mr McIntyre’s analysis of the data – which he had been asking for since 2003 – suggests that scientists at the Climate Research Unit of the Hadley Centre associated with the UK Met. Office have been using only a small subset of the available data to make their claims that recent years have been the hottest of the last millennium. When the entire data set is used, Mr McIntyre claims that the hockey stick shape disappears completely. 
Mr McIntyre has previously showed problems with the mathematics behind the ‘hockey stick’. But scientists at the Climate Research Centre (CRU), in particular Dr Briffa, have continuously republished claiming the upswing in temperatures over the last 100 years is real and not an artifact of the methodology used – as claimed by Mr McIntyre. However, these same scientists have denied Mr McIntyre access to all the data. Recently they were forced to make more data available to Mr McIntyre after they published in the Philosophical Transactions of the Royal Society - a journal which unlike Nature and Science has strict policies on data archiving which it enforces.
This week’s claims by Steve McIntyre that scientists associated with the UK Met. Office have been less than diligent are serious and suggest some of the most defended building blocks of the case for anthropogenic global warming are based on the indefensible when the methodology is laid bare.
This sorry saga also raises issues associated with how data is archived at the UK Met. Office with incomplete data sets that spuriously support the case for global warming being promoted while complete data sets are kept hidden from the public – including from scientific sceptics like Steve McIntyre. (continues)
From the comments:
Richard S Courtney Oct. 1st, 2009 link
[@] Nick Stokes: You wrongly assert to me:
"Richard “Briffa failed to state any criteria he used for his selection.”
This just isn’t true. He said
“Siberian larch (Larix sibirica) data from the area immediately east of the northern Ural Mountains, previously used by Hantemirov & Shiyatov (2002), were used as the Yamal regional chronology”
He’s using a data set which was previously used in the literature, and has made that clear. So you have to make a case that it was nonetheless necessary for him to use this alternative data. And I just can’t see it.”
Sorry, but your claim supports my statements that you dispute.
“Data which were in the possession of Briffa have been obtained for scrutiny by the scientific community. This revealed that there was a large data set and Briffa selected from that data set for conduct of his analysis. He published that analysis and its results.
Briffa failed to state that he had selected from a larger data set
Briffa failed to state any criteria he used for his selection.
These failures invalidate Briffa’s analysis. Indeed, they are a severe scientific malpractice that is tantamount to fraud in that they misrepresent the analysis which Briffa conducted.”
It does not matter that Hantemirov & Shiyatov (or anybody else) had used that selection: perhaps that is all the data that was available to them.
But it does matter that Briffa had the full data and chose to use a sub-set of it for an unstated reason. His paper could, for example, have claimed that he used that sub-set for comparison to Hantemirov & Shiyatov (2002) but, of course, that comparison study would have been a different study for a different purpose than the paper Briffa published.
Clearly, you have not grasped the point, so compare these two statements:
“We analysed the available data”
“We analysed a selection from the available data but we are not stating our reason(s) for making that selection and we will not allow others to see the data we chose not to use.
Can you not understand the difference?
The statement of a prima facia case of scientific malpractice against Briffa is not – as you assert – “ridiculous”: it is simply fact.
vg Oct. 1st, 2009 link
I think resign will be the minimum. I would not be surprised if major lawsuits are initiated worldwide for damages etc… once the reality of this sinks in. I still think it will take a few more days or weeks. The AGW are of course hoping this will go away with time.. so no discussion on this allowed. Im sure this is their policy currently. There is no choice for them now.
So there you have it. Strong evidence that harmful AGW aka climate change is at least a misconception and very likely the result of malpractice. The IPCC must be aware that the data was dodgy because of their excellent review procedure. What say you Ban ki-Moon?
Jennifer Marohasy's post link
Steve McIntyre's posts
Briffa's Avam-Taimyr Series link 1
Fresh Data on Briffa's Yamal #1 link2
Yamal: A "Divergence" Problem link3.
The prettiest contrarian, Jo Nova condemned it with vigour: link
DT writer James Delingpole commented on the HS a couple of days ago: link
Mail and DT columnist Chistopher Booker wrote earlier in September: link
Physicist Lubos Motl: link
Air Vent: link