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.
Read the complete story at the Financial Post
Sorry…I should have made it clear that the block-quote there in my previous post is from Jerry Haney, not brazil84.
The sad part in all of this is that, after the chickens come home to roost, so to speak, and the devastation wrought by poorly implemented measures which have risen from a chicken-little threat is finally realized, it is Science as a whole that will be degraded in the public esteem. I fear the backlash will be terrible.
“I’ve spent a lot of time discussing the science, but as the examples of cigarette smoking and evolution demonstrate, one is not going to be able to convince people on the basis of the science if they are sufficiently motived by their own biases not to believe it.”
So what? It’s impossible to convince someone of anything if they are sufficiently motivated by their own biases not to believe it.
An advocate will normally advance the strongest possible arguments and evidence in favor of his or her position. In the case of cigarette smoking, the best evidence is the fact that people who regularly smoke are much more likely to die from lung cancer. The fact that the surgeon general has determined that smoking causes lung cancer is interesting but only secondary.
Similarly, if somebody claims to have built a perpetual motion machine, the best argument against him is the fact that he is trying to make money by getting investors instead of simply selling his free electricity to his local power company. The fact that most physicists would hold that such a machine is impossible under currently accepted models is important but secondary.
And what about with CAGW? The best evidence in favor of CAGW is that people have constructed untested computer simulations which are consistent with past temperatures and future catastrophic warming. Which is weak evidence at best and warmists know it. Which is why they must resort to arguments from authority.
Joel Shore (11:49:49) : “They were chosen by the Republican majority to deal only with a narrow issue …”
As were the NAS panel also, I presume? So other than ad hominen attack are you saying that the Wegman panel conclusion was wrong?
“That being said, I think that Wegman showed poor judgment in going beyond his competency to address issues where he really did not have the background.”
But of course you do. You don’t seem to have any problem stating your own opinion but denigrate others who state theirs and who also (quite coincidentally?) disagree with yours. How quaint.
Joel Shore (11:49:49) : As for “appeals to authority”, while such appeals may not logically prove something to be true, it is generally true that scientific authorities are trusted more than just the “Average Joe” on scientific issues for very good reason. And, this is why “skeptics” tend to come up with grand theories to explain why all the scientific authorities are aligned against them.
There you go again. First establishing, by generalization, rather than by substantiation, that “scientific authorities” (“authorities” are entirely relativistic, btw) are more trustworthy, then expanding to the logical fallacies that a) all “skeptics” are “average joes” (pejorative all on its own), followed by the strawman that all “skeptics” believe “all the scientic authorities are aligned against them”. It seems the paranoia is yours, not the “skeptics”.
What McIntyre, and a good many “scientific authorities” are saying and showing, loudly, that many other “scientific authorities”, are, to use your own words, “going beyond their competency to address issues where they really do not have the background”. This includes some significant name brands in the Official Climatology.
brazil84 (12:12:48) :
But if CAGW was an acromym for Computer Aided Global Warming then the models are surely the strongest argument, eh? 🙂
Coppin:
“This includes some significant name brands in the Official Climatology.”
I agree. Anyway, which would be better evidence against McIntyre:
(1) Wegman was wrong on some important point where he came down on the side of McIntyre; or
(2) Wegman was appointed by Republicans.
DAV:
🙂
Nice suit Ross.
brazil84: I think you are missing the point. You are saying, “AGW is different because the evidence isn’t good whereas for the dangers of cigarettes and for the correctness of evolution, the evidence is good.” However, this is just your own personal judgment. To the cigarette companies and their proponents, including a few scientists, the evidence wasn’t good for a long time after it was good enough for most scientists. To the creationists, the evidence for evolution still isn’t good.
So, the question is, how are we to objectively tell when the evidence is good? And, it seems to me that the best way to do so is to have the reputable scientific bodies evaluate the scientific evidence. Having people who don’t like the conclusions second-guess them and demand their views to be taken seriously by policymakers is a recipe for the complete politicization of science. (It is fine and healthy for such second-guessing to occur within the scientific enterprise itself, although it works a lot better when it is done more through journals than blog postings.)
DAV says:
Actually, if my opinions were in strong contradiction to the opinions of nearly all of the scientists actively working and publishing in the field, then I would not really expect very many people to take my opinions very seriously. Similarly, I don’t think people should take Wegman’s opinions on climate science very seriously; his opinions on the details of the statistical method are entitled to more respect because that is his area of expertise. However, as I have noted, it is generally agreed now that the methods used by Mann et al is in the words of the NAS report, “not recommended” and indeed most scientists have moved on in the last decade, including Mann et al. themselves.
Paul Coppin says:
Not really. It has generally been widely accepted (across the political spectrum) that the National Academy of Sciences is an authority on scientific issues…and, in fact, its very charter is to provide scientific information to the federal government. And, it seems to have generally worked very well. And, there are other respected institutions such as the analogous bodies in other countries (like the Royal Society in London), AAAS, and the various professional societies such as the AGU, AMS, and APS. In this case, it is not like there is any great schism with some of these authorities on one side and some on the other.
Rather, the “authorities” on the other side consist of a few scientists who all get together at conferences sponsored by the Heartland Institute. Now, it takes a pretty warped view of the world to conclude that all of the scientific bodies that I mentioned have been corrupted and politicized and the Heartland Institute is now the upholder of non-politicized science!
“brazil84: I think you are missing the point. You are saying, ‘AGW is different because the evidence isn’t good whereas for the dangers of cigarettes and for the correctness of evolution, the evidence is good.'”
First of all, I said nothing about evolution because we are not allowed to discuss evolution on this board. If you wish to discuss evolution, feel free to post to my blog.
Second, I am saying nothing about AGW, because there is little doubt that mankind’s activities are likely to have some kind of warming effect on the climate. The question is about CAGW.
Third, it is you who is missing the point. I do maintain that the evidence for cigarette smoking causing lung cancer is good and the evidence for CAGW is not good, but that’s not my point.
Let’s assume for the sake of argument that the evidence for CAGW is strong. In that case, proponents of CAGW would need only to point at the evidence without relying on arguments from authority. And yet proponents of CAGW appeal to authority seemingly without end.
“And, it seems to me that the best way to do so is to have the reputable scientific bodies evaluate the scientific evidence. ”
If you had to make one and only one point to convince someone that smoking cigarettes causes lung cancer, what would that point be?
“If you had to make one and only one point to convince someone that smoking cigarettes causes lung cancer, what would that point be?”
Perhaps a better question would be this:
What is the very best piece of evidence that smoking cigarettes causes lung cancer?
“To the cigarette companies and their proponents, including a few scientists…”
Are you aware that one of those scientists was Ronald Fisher, himself? It would seem that statisticians are to be ignored regardless of stature if they hold minority opinion and regardless of the fact that the basis of the majority side is statistical in nature. Who would be better at passing judgement on statistical studies? Makes me wonder about how you yourself select authority.
You really should reconsider you stance on authority. Apparently you are here to proselytize so take some friendly advice on salesmanship: It’s a bad idea to assault the judgement of a man you are trying to convince — especially so by pointing out his terrible choice in mates and friends.
Also, try to keep to the point. If you have in pearls of wisdom why would you want to continuously bury them under extraneous BS? Not only are you making it undesirable to search for them but they will also smell better when examined.
brazil84 made a rather pointed observation posed as a simple question:
You are concentrating on (2) when applying yourself to (1) would be more productive. Why? Lacking your answer, you must forgive us our cynical assumption.
“As for “appeals to authority”, while such appeals may not logically prove something”
They don’t. We are in agreement.
“…it is generally true that scientific authorities are trusted more than just the “Average Joe” on scientific issues for very good reason.”
So we go from stating that Appeals to Authority don’t prove anything…
…to the same Appeal to Authority worded in the form of a generalization.
A waste of time, disk space, and bandwidth. 😉
Andrew
Joel says “It is fine and healthy for such second-guessing to occur within the scientific enterprise itself, although it works a lot better when it is done more through journals than blog postings.”
How many “Scientific” journals asked to see Briffa’s raw data when he published his results? Ans: one. How many journals accepted articles using Briffa’s [snip] results without asking for the raw data which we now know to be completely inadequate. “The Russians only gave him the 12 trees” is the current excuse by Gavin at the censoring RealClimate site. Why don’t you go over there and ask how many studies used Briffa’s [snip] results without the raw data? Ask him when those studies will be redone. He will say, it doesn’t really matter. We have moved on. Look over here at these boreholes!
Sorry about that. I did not mean to imply falsified. I merely meant processed, but got a bit carried away. Thanks for cleaning.
“Andrew_KY”
Oh sh*t. My identity slipped out.
Back to my Impenetrable Fortress in the Arctic Ice Caves! Mwuahahahaha! 😉
Andrew
brazil84:
(1) There are only so many times that one can repeat scientific arguments that are being ignored. Believe me, I have done so many times. Go look and see how many times I have explained in gory detail to Smokey why graphs he has posted are deceptive. There is only so much one can do to try to convince someone of something if they don’t want to be convinced.
(2) Science is hard and the climate science is especially hard. There is no shortcut “killer” argument or “smoking gun” piece of evidence. One simply has to look at and evaluate the totality of the evidence, which is what the appropriate scientific bodies have done. This is, in fact, why people who contest scientific consensuses in the public sphere, whether they involve AGW, evolution, or smoking can do so with such success.
(3) You’ve presented no evidence that those arguing the link between cancer and smoking or arguing the case for evolution cite authority less. I mean, what exactly is one to say to someone who just keeps saying that the scientific evidence doesn’t convince them? At some point, you have to say, “Well, fine. However, it does seem to convince people who seem more qualified to judge.”
Well, the reason why I haven’t argued that, as I have explained already, is that it is not so much that Wegman was wrong but that he is irrelevant. The science has long moved on from the issue of whether the specific method that Mann et al wrote up in their first paper in this field is a good method. The NAS report addresses the broader questions that are actually more relevant (and it doesn’t get sidetracked into analysing Mann’s social network). That is why the NAS report lives on whereas the Wegman report has essentially vanished into obscurity except amongst those of a certain persuasion.
Eric (skeptic): So, now that Steve McIntyre has the data that Briffa used and he has the various data from the Mann et al. (2008) article and he has written innumerable confusing blog posts about them all that have received worshipful responses from his acolytes, when are we going to see the journal articles by him? Why is it that he seems more interested in addressing his followers and writing posts that then prompt various other blog posts and columns in the echo chamber rather than actually addressing his scientific peers?
Even some skeptics like “TCO” seem to have tired of McIntyre’s approach.
“Even some skeptics like “TCO” seem to have tired of McIntyre’s approach.”
Add the Appeal to TCO to the list of logical fallacies. 😉
WOW. I did not see that one coming.
Yes, I’m back already. 😉
Andrew
“There are only so many times that one can repeat scientific arguments that are being ignored.”
So what? If your scientific arguments are ignored, it’s unlikely your appeals to authority will accomplish anything either.
More likely, your scientific arguments are being rebutted so you are retreating to the usual refuge of warmists — appeals to authority.
“There is no shortcut ‘killer’ argument or ‘smoking gun’ piece of evidence.”
Yep. There isn’t even any convincing evidence, and that’s the problem.
“You’ve presented no evidence that those arguing the link between cancer and smoking . . . cite authority less.”
And I haven’t made such a claim either. So what?
Let’s do this. I have two simple questions for you:
(1) In your opinion, what is the very best evidence that smoking cigarettes causes lung cancer?
(2) In your opinion, what is the very best evidence that the CAGW hypothesis is correct?
________________
“Well, the reason why I haven’t argued that, as I have explained already, is that it is not so much that Wegman was wrong but that he is irrelevant. The science has long moved on from the issue of whether the specific method that Mann et al wrote up in their first paper in this field is a good method. ”
In that case, the fact that he was (apparently) appointed by Republicans is irrelevant too. And yet somehow you felt the need to mention it.
I notice a difference between Ross McKitrick and Steve McIntyre. Ross McKitrick pulls no punches and is pretty forthright in what he has to say.
Steve McIntyre on the other hand after exposing what seems to be, at the very least, an enormous misrepresentation of one proxy, to show alarming unprecedented global warming in the last 50 years, on the basis of which the IPCC declared as such, seems to spend the rest of his time almost apologising for his discovery.
This gives ammunition to his detractors who say his discovery is of no consequence and he does this kind of thing just to score brownie points.
Joel,
I’m not sure if the spam filter ate my last post or not. Will try again. Steve has exhaustively and carefully reported on his results. On the subject of this thread he published here:
http://www.climateaudit.org/pdf/mcintyre.workshop05.pdf
followed up many times including here:
http://www.climateaudit.org/?p=548
Scroll to figure 2. That’s all the information he had regarding Briffa Yamal.
Finally last week he got the raw data:
http://www.climateaudit.org/?p=7241
Looking at this new figure 2, do you see the problem?
Joel, worshipful? Most of Steve’s regulars correct him regularly. His 05 paper on Polar Urals was followed on his blog in 06 with Yamal mean ring width versus Briffa’s RCS with a greatly exaggerated HS shape. Now he finally has the raw data and the mean ring width from 06 appears to be correct, but not the RCS.
Alan
Thanks for your explanation.
So to be clear the hockey stick chart is comprised of instrument data for the 20th century and tree ring data for pre 20th century?
As this chart shows.
http://minnesotansforglobalwarming.com/m4gw/2009/10/03/RisingTemps.jpg
Here is the original source
http://www.pca.state.mn.us/oea/reduce/climatechange.cfm
And the new revelation is if you use just the tree ring data for the 20th century as well the temperature remains flat.