For those who don’t know, Ross McKitrick of the University of Guelph co-authored the first paper with Steve McIntyre debunking Michael Mann’s first Hockey Stick paper, MBH98. Ross wrote this essay in today’s Financial Post, excerpts are below. Please visit the story in that context here and patronize their advertisers. – Anthony
Flawed climate data
Only by playing with data can scientists come up with the infamous ‘hockey stick’ graph of global warming
Ross McKitrick, Financial Post
Friday, October 2, 2009
Beginning in 2003, I worked with Stephen McIntyre to replicate a famous result in paleoclimatology known as the Hockey Stick graph. Developed by a U.S. climatologist named Michael Mann, it was a statistical compilation of tree ring data supposedly proving that air temperatures had been stable for 900 years, then soared off the charts in the 20th century. Prior to the publication of the Hockey Stick, scientists had held that the medieval-era was warmer than the present, making the scale of 20th century global warming seem relatively unimportant. The dramatic revision to this view occasioned by the Hockey Stick’s publication made it the poster child of the global warming movement. It was featured prominently in a 2001 report of the U.N. Intergovernmental Panel on Climate Change (IPCC), as well as government websites and countless review reports.
Steve and I showed that the mathematics behind the Mann Hockey Stick were badly flawed, such that its shape was determined by suspect bristlecone tree ring data. Controversies quickly piled up: Two expert panels involving the U.S. National Academy of Sciences were asked to investigate, the U.S. Congress held a hearing, and the media followed the story around the world.
The expert reports upheld all of our criticisms of the Mann Hockey Stick, both of the mathematics and of its reliance on flawed bristlecone pine data.
…
Most of the proxy data does not show anything unusual about the 20th century. But two data series have reappeared over and over that do have a hockey stick shape. One was the flawed bristlecone data that the National Academy of Sciences panel said should not be used, so the studies using it can be set aside. The second was a tree ring curve from the Yamal Peninsula in Siberia, compiled by UK scientist Keith Briffa.
…
But an even more disquieting discovery soon came to light. Steve searched a paleoclimate data archive to see if there were other tree ring cores from at or near the Yamal site that could have been used to increase the sample size. He quickly found a large set of 34 up-to-date core samples, taken from living trees in Yamal by none other than Schweingruber himself!Had these been added to Briffa’s small group the 20th century would simply be flat. It would appear completely unexceptional compared to the rest of the millennium.
Combining data from different samples would not have been an unusual step. Briffa added data from another Schweingruber site to a different composite, from the Taimyr Peninsula. The additional data were gathered more than 400 km away from the primary site. And in that case the primary site had three or four times as many cores to begin with as the Yamal site. Why did he not fill out the Yamal data with the readily-available data from his own coauthor? Why did Briffa seek out additional data for the already well-represented Taimyr site and not for the inadequate Yamal site?
Thus the key ingredient in most of the studies that have been invoked to support the Hockey Stick, namely the Briffa Yamal series, depends on the influence of a woefully thin subsample of trees and the exclusion of readily-available data for the same area. Whatever is going on here, it is not science.
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I wonder what Prof. Fritz Hans Schweingruber thinks of the use of his “Schweingruber series” ?
As if the validity of tree rings as temperature proxies wasn’t suspect enough; not only because of the separation of variables problem, but also the sampling statistics, particularly with core bored trees; you would think that one would want to gather as much available data from any site to show some sort of continuous history of that site.
After all, the temperature anomaly graphs from actual ground measurement stations, are each important for their own historical integrity; but there is less expectation that two different sites would fit together well, although they may both follow some major trend events.
So to me; being an ignoramus when it comes to tree rings, the integrity of the Yamal site ring data is served batter by using ALL the available trees; rather than ANY subsample of those trees, wedded with trees from some different site.
So although I can’t appreciate the fine points in Steve’s analysis; I can certainly see why why both Steve and Ross, would yell “tilt” at the way this data was originally handled.
No point in accusing Briffa of malfeasance; that is out on the limb as I see it; but it seems to me that he could have done a more scientifically clean job at the outset.
Certainly keeping the data secret for so many years doesn’t help his case.
On another matter, I see the JAXA ice graph for 2009 did finally cross back below the 2005 line; but then on looking at the DMI temperature graph, one might surmise that that dramatic temperature uptick temporarily slowed the ice expansion to allow the 2005 ice to get ahead; but now that the temperature has resumed its downward plunge, the ice curve seems to have steepened back up again.
I’m not going to propose any definitive mathematical relationship between those two graphs; but it is nice to see that they are not inconsistent with each other; and 2009 appears to be about to give us some perfectly boring normal ice expansion still heading in the direction of retreating from the 2007 low.
I have noticed the tendency of some of the regular AGW supporters who apparently work institutionally in this climate field, and post on WUWT, to belittle the comments of interested bystanders who are not active institutional researchers living off the taxpayer’s backs. Well we are simply not qualified to understand or be critical of the long established experts in the field.
The problem for those AGW supporters, is that we bystanders do no (at least I don’t) take our positions standing alone out in the park on a soap box peddling our wares.
We get our inputs from all the protagonists who are in fact equally expert researchers with long careers in this field; and on all sides of the issues.
So those who would nag at us here on WUWT, should stop worrying about what WE are saying or suggesting about climate matters; and start concerning themselves with the strong dissenting views of well recognized experts whose credentials are at least the equal of anybody the AGW supporters want to put up on a pedestal.
And the numbers of such expert workers in the field who are abandoning the AGW story in droves; is what they should concern themselves with. That is where WE bystanders are getting our clues; that the long held views that were all resolved and accepted as gospel 50 years ago; are crumbling under the revelations of modern research tools, that don’t support the religion that is still being taught in schools.
So I plan to continue to dig into the pile of rubble whenever my own credentials are suitable to the task; I’m not easily put off by the claims of those elites, who would say I should learn their witchcraft methodology first, before proposing alternative views.
George
Excellent explanation by Ross McKitrick….. Keith Briffa has pretty much disgraced himself…..
In light of what we now know, due to Steve McIntyre’s persistence and diligence, there can be little denying that Briffa was knowingly hiding the data because he knew that it would show his deliberate manipulation.
This paragraph is just so damning to Briffa….. “But an even more disquieting discovery soon came to light. Steve searched a paleoclimate data archive to see if there were other tree ring cores from at or near the Yamal site that could have been used to increase the sample size. He quickly found a large set of 34 up-to-date core samples, taken from living trees in Yamal by none other than Schweingruber himself!Had these been added to Briffa’s small group the 20th century would simply be flat. It would appear completely unexceptional compared to the rest of the millennium.”
OT
Another big win. The planets must be aligning and the gods smiling down on us.
Chicago was eliminated from the Olympics.
It would have elevated Obama to god like status if they had gotten the games, but now he is confirmed to be mortal.
I’m still confused ( I’m not a scientist) maybe someone can answer this.
Concerning the Hockey Stick Chart.
Is it tree ring data before 1850 and weather station data after?
George E. Smith (08:40:20) :¨
“I should learn their witchcraft methodology first, before proposing alternative views”
All important breakthroughs in science, art, etc. were made by outsiders.
A few examples: Famous architect Le Corbousier was the clean boy of an architec´s office, Thomas Alva Edison didn´t finish first grade school..etc,etc.
Both kind of people are needed, the discoverers and the followers, but not the liars.
He doesn’t really say much here though, does he? What about the analysis methods? Suitability? Anything scientific at all?
Well said George!
Down with the establishment! We are all experts now!
I love this website — I am not a scientist by any measure, but am a very concerned small businessman who never has bought into the AGW spin — Can you all help me out with an off – topic question — so I’m watching the news this AM, and there is Sigourney Weaver from Alien fame, and she is talking very authoritatively about the ocean absorbing CO2 and forming carbonic acid — so therefore shellfish are not reproducing, plankton are smaller and the coral reefs are shrinking — my bs antenna went up right away — so my question is, is co2 creating these type of terrible sounding conditions in the oceans ??
Best article I’ve read yet. I’m passing this one on to some folks in my address book because it’s very easy to understand.
This coming on the same day as Obama jumped the shark in Copenhagen is just too delicious to be believed!
Check out the aims and objectives of British climate science in this DEFRA/Hadley contract.
http://randd.defra.gov.uk/Document.aspx?Document=GA01012_6499_FRP.doc
It seems to me that Ross McKitrick’s reading of the National Academy of Sciences report on temperature reconstructions ( http://www.nap.edu/catalog.php?record_id=11676 ) is somewhat selective. For example, in the summary they say:
This statement would seem to contradict McKitrick’s assertion that “Most of the proxy data does not show anything unusual about the 20th century.”
They also make the following very important point:
I am also confused by McKitrick’s statement that “two expert panels involving the U.S. National Academy of Sciences were asked to investigate”. If he is referring to the Wegman panel as the other one (which was convened by the Republican majority on the Congressional Committee), I am not sure how it involves the U.S. National Academy of Sciences. Wegman was “past chair of the National Research Council’s Committee on Applied and Theoretical Statistics” but I don’t think his role on the the panel that the Republicans appointed was in any way officially associated with the NAS.
joshv on the AirVent blog found this one:
Gavin quoted HALF of a sentence, in support of his claim that McIntyre is accusing Briffa of intentional cherry picking.
The half he quoted:
“In my opinion, the uniformly high age of the CRU12 relative to the Schweingruber population is suggestive of selection” (McIntyre)
The full sentence:
“In my opinion, the uniformly high age of the CRU12 relative to the Schweingruber population is suggestive of selection – in this respect, perhaps and even probably by the Russians”
Good article in layman’s terms for all to understand. All this potential waste of trillions of dollars across the globe for TWELVE TREES .
Brent in Calgary
Robinson (08:28:01) :
Excellent and clearly written article by Ross. I don’t know how influential the financial post website is, but it seems the word is starting to spread out of the blogosphere as to how we’ve all been gamed by The Team.
Try spreading the word yourself. Find an articulate summary (such as that written by McIntrick)
I do, I do. I specialize in being a bigmouth about this stuff.
By the way, who is Mcintrick? The bastard love child of Steve and Ross? 🙂
The file stamp is more than likely date of creation, rather than date of copy to wherever it was copied to. In any case, I suppose you could put some files up on an obscure server somewhere for all to download, only never telling anyone where they were 😉 In both cases you’re likely to be thwarted.
Gordon Ford (08:20:51) :
PS – If the (t)ruth were known Canadian Conservatives are probably to the left of American Democrats!
As someone who has lived in both countries I can confirm your hypothesis.
For instance you will not find many Canadians, even true blue Conservative, who want to revert to a private heath care system.
On the other hand Steve McIntyre at CA has made it a point over the years to remind his more conservative readers that he is fact a liberal.
This latter fact is unknown to most AGW supporters (and foes too) here in the US.
While I usually chuckle when I read some troll drool that links McIntyre with the far right, this attribution of skepticism to the right is way off base. I know of several people personally who are “red banner” lefties that don’t buy the AGW line but support it for political reasons. I even know a few who are vocally skeptical and don’t support it.
Sad but true. The truth will only out when it is too late. The consensus rules even though it is not a consensus at all. Keep fighting for the truth. It will in any event manifest itself in the coming years but maybe not soon enough to save us all from the debilitating and potentially disastrous effects on our society.
Please help me clarify this… how many “old” trees are on Earth? Why such little sampling in such a remote area? If climate is global, could I just use the maple tree that is in my backyard (which must be 300-400 years old – it’s huge) and get my very own climate curve? On that note, maybe I would not trust that curve after all since every time it is a hot and dry summer (Fraser Valley, BC) it looses its bark.
See my email to Briffa. I’m not holding my breath…
Dear Professor Briffa, my apologies for contacting you directly, particularly since I hear that you are unwell.
However the recent release of tree ring data by CRU has prompted much discussion and indeed disquiet about the methodology and conclusions of a number of key papers by you and co-workers.
As an environmental plant physiologist, I have followed the long debate starting with Mann et al (1998) and through to Kaufman et al (2009).
As time has progressed I have found myself more concerned with the whole scientific basis of dendroclimatology. In particular;
1) The appropriateness of the statistical analyses employed
2) The reliance on the same small datasets in these multiple studies
3) The concept of “teleconnection” by which certain trees respond to the “Global Temperature Field”, rather than local climate
4) The assumption that tree ring width and density are related to temperature in a linear manner.
Whilst I would not describe myself as an expert statistician, I do use inferential statistics routinely for both research and teaching and find difficulty in understanding the statistical rationale in these papers.
As a plant physiologist I can say without hesitation that points 3 and 4 do not agree with the accepted science.
There is a saying that “extraordinary claims require extraordinary proof”.
Given the scientific, political and economic importance of these papers, further detailed explanation is urgently required.
Yours sincerely,
Dr. Don Keiller.
http://www.edmontonjournal.com/business/energy-resources/Climate+fears+based+lies+Calgary+told/2058176/story.html
Melanie Phillips in the ‘Spectator’ is saying that there is a problem with Science’s peer group process itself, which is a really huge issue.
IMO, it’s clearly a post-Enlightenment world now, and Science (at least as practiced by university staff for a living) is apparently slipping back into that region occupied by university theologists in pre-Enlightenment times.
To paraphrase an Enlightenment Joke used against those theologists and their ‘studies’ at that time; “How many angels can dance on the butt of a tree?”
RC’s post shows up in the Google News feed along side Ross’s article. Yet another indicator that RC has some serious PR flacks behind the scenes (presumably Fenton Communications) who know how to get a simple blog post to show up as a news story of equal weight to a Financial Post article.
Those of you who get frustrated by RC are under the mistaken impression that its a science blog. In fact, it’s a professional, highly sophisticated PR production.
I believe Delbeke’s observation deserves a closer look and consideration.
Wayne Delbeke (08:28:08) : “. . . If you subtract 800 from 2000 you get 1200 – so if CO2 increases follow warming by 500 to 800 years, is it possible that the Medieval Warming from 800 to 1500 is in part responsible for the increase in CO2 we see today . . .”
If that’s what the Vostock cores tell us, the rise in CO2 now has a new explanation.