November 14, 2005
Why Does the Hockey Stick Debate Matter?
Posted to Author: Others | Climate Change
Post by Ross McKitrick
Roger Pielke Jr. has posed a challenge to Michael Mann and us to briefly explain why each of us thinks the ongoing hockey stick debate matters. The technical content of the debate is summarized elsewhere (here and here; Our papers are linked under the heading “articles” (right hand column), and an overview paper by Ross McKitrick is here) and I won’t re-cap it here. That it matters is demonstrated by the enormous traffic on blog sites, the volume of comments to science journals, the opening of a Congressional investigation, etc. Obviously a lot of people find that it matters.
So: why does it matter?
1. It matters because it concerns the validity of an influential scientific paper. Mann’s 1998 and 1999 papers (which I’ll call “MBH”) have been heavily cited and highly influential. The paleoclimate field seems to have organized itself around them: other papers since then have gained prominence in proportion as they appear to back up MBH, whereas papers that contradict it have little prospect of being published or are relegated to lower-profile outlets. A popular icon in paleoclimate circles these days is what can be called a “spaghetti graph,” showing a pastiche of climate reconstructions from a small group of authors who call themselves the “Hockey Team”. They agree on few details, other than that the Medieval Warm Period is not as warm as the 20th Century.
Yet MBH turns out to have major flaws that fundamentally undermine its conclusions. These issues are interesting in their own right because MBH is a famous paper. But they also have wider scientific implications. MBH was “helped” along to its conclusions by some very convenient decisions about small changes to methodology, small edits to data series and not-so-small decisions about using contaminated bristlecone data. Maybe some of the other studies that appear to confirm MBH were also “helped” along so they would appear to agree with it. Efforts to evaluate the whole spaghetti graph has encountered maddening secrecy by the other authors concerning their data and methods, just as with MBH. But enough has been discovered to support a couple of assertions.
(a) The other spaghetti graph diagrams lack robustness. They all depend on delicate editing of weak data and just-so methodology. None are al dente: these are very soft noodles, and a plateful of weak results does not add up to a strong conclusion.
(b) There is an unexamined problem of spurious statistics in multiproxy constructions. Hockey team methods mine autocorrelated proxy data for simple correlations with autocorrelated temperature data. It is a classic recipe for spurious results, as has long been known in econometrics following the seminar studies of Granger, Engle and Phillips. What was predictable on theoretical grounds is now emerging empirically: proxies that extend past 1980 have no explanatory power for recent temperatures. And by implication, the existing corpus of multiproxy studies provides spurious information about the historical climate. Despite occasional claims of technical rigour, none of the spaghetti graph lines come from papers where the spurious regression problem was dealt with.
2. It matters because it exposes the uncomfortable reality about journal peer review. MBH(98) was published in Nature, considered by some the world’s “leading” scientific journal. Nature never verified that data were correctly listed: as it happens they weren’t. Nature never verified that data archiving rules were followed: they weren’t. Nature never verified that methods were accurately stated: they weren’t. Nature never verified that stated methods yield the stated results: they don’t. Nature undertook only minimal corrections to its publication record after notification of these things, and even allowed authors to falsely claim that their omissions on these things didn’t affect their published results.
In light of this, it is far past time for a wide-ranging discussion on what ‘peer review’ actually is. Policymakers routinely appeal to it as some kind of quality assurance guarantee. But obviously it isn’t. It serves some purpose internal to the world of scientific publishing, but policymakers’ beliefs about what peer review guarantees are for the most part sheer fantasy.
3. It matters because it exposes the uncomfortable reality about the IPCC. The IPCC’s use of the hockey stick was not incidental: it is prominent throughout the 2001 report. Yet they did not subject it to any independent checking: revealing an astonishingly cavalier attitude to the quality of their case. This raises the question of whether anything in the report was subject to serious, independent checking. They allowed chapter authors to heavily promote their own work with little or no oversight. They published false claims about the hockey stick’s statistical robustness and have never made any effort to retract them. On the basis of the MBH claims, their 2001 report reversed their 1990 conclusions about the MWP, and over-rode their 1995 warnings about not relying on bristlecone data, in order to promote the conclusions implied by the hockey stick. They encouraged governments around the world to rely heavily on a graph they themselves had not independently checked. One reason the hockey stick debate matters is because it exposes as worthless the guarantees given up to now about why the world should rely on the IPCC.
In this light I have no patience for the reaction by scientists to the Barton investigation. Why shouldn’t legislators begin asking questions about how the IPCC (and its allies in the science community) produce their reports? Policymakers have strong evidence that the IPCC process did not actually involve the rigorous checks and balances that they boasted of when releasing their 2001 report. It would be negligent of lawmakers not to open a wide-ranging investigation of this. Anyone who thinks the Barton investigation is unnecessary must think that IPCC reports don’t really matter: but they do, which is one reason why the hockey stick debate also does.
4. It matters because it exposes the uncomfortable reality about how governments use scientific information Canada (and many other countries) used the hockey stick heavily in their promotion of the Kyoto Accord. It is still prominent in government publications. Canada boasts of having spent $3 billion on climate change initiatives, much of it going to research. Yet for all the billions of dollars spent, and for all the proliferation of staff working on the matter, no one in government checked the hockey stick. Even when Canada’s chief climate science advisor and the Prime Minister’s own scientific advisor were personally informed about flaws in the hockey stick, no effort was made to remedy the government’s error. We have never been contacted by a single federal government scientist or other staff member for information on this topic, even though Environment Canada has in the past made heavy use of the hockey stick and more recently has issued communications supposedly providing “expert” commentary on my work, commentary that is predictably fallacious. Governments apparently use science when it suits them, as a promotional policy tool, with little regard to the facts of the matter. Perhaps it is naïve of me to have expected otherwise, but the realization still disappoints.
5. It matters because it exposes an uncomfortable reality about the culture of climate science. It took two outsiders to do all this work. Climate scientists in the field ignored the glaring problems in MBH for five years, and only seemed to get engaged after Stephen McIntyre and I began publishing our work. Since then the “engagement” of climate scientists has primarily consisted of ridicule, nitpicking, obstruction and catcalls from prominent scientists, especially those involved with the IPCC and the University Corporation for Atmospheric Research on Colorado. The few who have offered support tend to do so privately or anonymously.
We have tried to get data and methods from a long list of IPCC scientists who published prominent papers. The near-universal response is a hostile refusal to disclose, followed by stonewalling, delay and excuses. Lately a few have taken to publishing gripes and grievances about me in Eos. They complain that they don’t have time to archive their data sets, yet they seem to have lots of time to write editorials complaining about my inquiries.
These climate scientists seem to want to have things both ways. They are demanding that society set costly policy based on their work, yet they refuse to allow scrutiny of it. As a resident alien in IPCC-land, I have found it to be a culture of secrecy and conformity, to a degree that is incompatible with a healthy, vigorous intellectual culture. They can’t escape external investigation forever, and when it happens I believe a lot more skeletons will fall out of the closets.
And I do not believe I am alone in drawing such conclusions. The opening of the Barton investigation is the tip of the iceberg. The big scientific organizations that hyperventilated about it failed to note the ridiculous contradiction in their position. They insist that the scientific community should be left alone to handle the task of reviewing and critiquing influential studies, yet they not only failed to do it when it was needed, but routinely acquiesce in the widespread culture of secrecy that effectively prevents it from happening. It was only a matter of time before these issues got put on the table and subject to a top-to-bottom examination. The hockey stick debate seems to have been a catalyst, one more reason it matters to so many.Posted on November 14, 2005 06:03 AM
Steve and I began by pitching ideas to each other, both written in the first person (i.e. Steve). In the end we couldn't decide how to merge them so we sent both in. The first-person references in the final 3 paragraphs are on Steve's behalf, though of course they are my views as well.
Posted by: Ross McKitrick at November 14, 2005 10:30 AM
These guys have had their hearing (in GRL) and now they're just whining about not getting backed up by von Storch and Huybers. Their game has now shifted to preparing the ground for an attack (abetted by the AEI/WSJ/Barton/Inhofe axis) on the forthcoming AR4. I'm sure everyone will think highly of Roger for assisting them with that effort.
P.S. -- Roger, regarding McKitrick in particular, aren't you just a tad embarassed to be providing a forum to someone who has been shown to have engaged in out-and-out pseudo-science? I refer here to the book with Essex and the paper with Michaels.
Posted by: Steve Bloom at November 14, 2005 03:33 PM
Since I'm pretty sure MBH won't be responding here, you'll probably have to make do with my answer to the question, which is given here: http://mustelid.blogspot.com/2005/11/big-picture.html but can be summarised as "if anyone were, hypothetically, to enquire why *others* should continue to care about it... Why is this fight important to the rest of us? The answer is: you shouldn't. It isn't."
Posted by: William Connolley at November 14, 2005 03:38 PM
Also, http://www.meteo.psu.edu/~mann/shared/articles/MannetalJClimate-inpress05.pdf may be of interest (hat tip: John Fleck: http://www.inkstain.net/fleck/?p=1193)
Posted by: William Connolley at November 14, 2005 04:03 PM
I appreciate your comments here, but have to admit being baffled by your criticism of us for asking the priciples involved in one of the the most public debates on climate change to enage the rest of us in answering "so what?".
For the record we offered Mann and colleagues the same opportunity. They declined, though a few have participated in the comments, such as William Connelley. That offer still stands and they have the same forum.
Here at Prometheus we think that debate is advanced by engagment and providing fora for discouse, and not by silence and exclusion. We have faith that our readers are perfectly capable of evaluating competing claims, which is one reason why we seek to publish different points of view.
Posted by: Roger Pielke Jr. at November 14, 2005 04:54 PM
Steve Bloom, William Connolley :
Posted by: fFreddy at November 14, 2005 05:30 PM
In defense of the IPCC, I think it's important to remember what it's purpose is: to summarize the peer-reviewed scientific literature. If there are errors in the peer-reviewed scientific literature, then the IPCC will contain the same errors.
In that view, expecting the IPCC to somehow quality check or verify the peer-reviewed scientific literature would create more problems than it would solve. If the IPCC did take on that responsibility, who would check them? What would happen if the IPCC decided that MM05 was a bunch of crap, and should be omitted from their summary? That could easily happen, and I could only imagine the howls of protest that would result. There would be accusations of a cover-up, of suppression of dissent, etc. It would create a big mess (yes, bigger than the present one!).
I view the present controversy about the hockey stick as evidence that the scientific system works. If the scientific community were attempting to suppress dissenting views, then GRL would never have published the MM paper, and other scientists would not drawn into the debate. At present, the scientific community is evaluating the contrary claims. That's the way science improves our knowledge.
Posted by: Andrew Dessler at November 14, 2005 10:13 PM
How about Nature?
Where is the R script that replicates Mann to the last decimal? How then can "the scientific community evaluate the contrary claims" ?
Posted by: Hans Erren at November 15, 2005 01:12 AM
Freddy - I noticed that neither you nor the poster have addressed any of my points. I take it that means you agree with me. No? Right - so please cut out the tedious rhetorical games.
Hans: if we paid attention to every paper rejected in Nature we'd be drowning in nonsense. As for R: since Manns code was fortran, why on earth do you expect him to re-code his stuff in R just for your personal pleasure?
To take up one of the points: "other papers since then have gained prominence in proportion as they appear to back up MBH, whereas papers that contradict it have little prospect of being published or are relegated to lower-profile outlets". This is nonsense. Can you say "Moberg"?
Posted by: William Connolley at November 15, 2005 06:25 AM
Did Mann release the complete fortran code then?
As for Moberg, his proxies are also not available.
Which brings us to the major discovery of M&M:
Sorry, that ain't science,
Posted by: Hans Erren at November 15, 2005 08:14 AM
Hans asks: "How then can 'the scientific community evaluate the contrary claims' ?"
The answer is ongoing, in the scientific literature, by M&M and a host of others. There's a quite rich record of publication on this question using different data sets and different methodologies, all attempting to refine our understanding of paleoclimate record.
That's where the discussion is going on that is useful to our understanding of climate changes past, present and future. This "hockey stick" argument has just become a tedious sideshow, distracting from the important discussions.
Posted by: John Fleck at November 15, 2005 08:56 AM
Let me jump in here and observe that every one of the comments thus far have ignored the actual texts of McIntyre and McKitrick.
This can only be for a few reasons. Perhaps the arguments are so compelling that respondents are caught speechless. Somehow I doubt this. Perhaps engaging these issues would distract attention from what doesn't matter (to most of us), and I have to be careful here because I am heading right back into the territory of unwelcomed metaphor:
So let me turn the challenge back to our various commenters and lurkers, so what about "so what"? I promise to give my 2 cents by the end of the week!
Posted by: Roger Pielke Jr. at November 15, 2005 09:21 AM
Ok Roger, here're my thoughts on the importance of the hocky stick debate:
1) important politically. much like the missing weapons of mass destructions in the iraq debate, advocates opposed to mitigation efforts can use this mess as an anvil to hammer their scientific uncertainty argument. (e.g., see arguments in post above)
2) minor importance scientifically. the temperature of the MWP gives us some information about past climate variations. while an interesting scientific question, the warmth or not of the MWP does not change the fact that the earth is presently warming and that we expect it to warm in the future. do I think this debate could/should fundamentally change the scientific community's view of anthropogenic climate change? not in any major way (although I always keep an open mind about these things).
3) should you care about the debate? I do, because I love a good science fight. also, contrary to those who think this shows how the scientific system failed, on the contrary I think this is an example of how well science works. those criticizing science should spend some time reading the latest issue of GRL instead of demanding a stool sample from Mann.
Posted by: Andrew Dessler at November 15, 2005 09:55 AM
Why is the Hockey stick debate so important? Because if the Mann study is correct than there is very strong evidence that CO2 is the main driver of climate change. If it isn't, then CO2 is not the main driver and may not be a primary driver of climate change. THAT is the reason it is so important! It is fundamental to the whole debate of Anthroprogenic global warming.
Following on of Mr. Connolley's links, I found the following statement to be the summation of his stance:
"The world is getting warmer, we're causing it, and it will continue to get warmer in the future."
The first statement is generally excepted as true. For the last 30-40 years, all data indicate a warming trend, not dissimilar to the warming recorded at the beginning of the 20th century.
The second part is not only speculation, it is also contrary to the data. Had he said, "we appear to be causing some of it." then I would have no complaint, for it would allow for the general uncertainty that is actually quite large, as well the input of 'natural' variability, for which the evidence is quite strong, despite the fact that our understanding of natural variability is best described as rudimentary.
Such an emphatic statement (we're causing it) is not only unscientific, but reveals a faith-based component to his argument.
The third part ("...and it will continue to get warmer in the future.") is also faith based if stated as a certainty.
I also found Mr. Dressler's comment, "those criticizing science should spend some time reading the latest issue of GRL instead of demanding a stool sample from Mann." very disturbing. The request has been for the data and methodology used to get the results of a very important climate study. The results of this study are being used to dictate global policy that effects every man, women and child on the planet. If that is not important, than what is?
Posted by: Jim Clarke at November 15, 2005 10:43 AM
I disagree with Mr. Clarke's assertion that the results of the hockey stick prove or disprove that CO2 is driving the most recent warming. The hockey stick sheds light on whether the temperature of the MWP relative to today. This has little to say about the recent warming, and even less about whether continued increases in CO2 will cause continued warming. I hypothesize that this misunderstanding is why people attribute more importance to the debate than it should have.
I would also ask Mr. Clarke why the present debate, occurring in the pages of GRL, is not acceptable to those who doubt MBH? Will it not eventually get the correct answer? Do you want a stool sample from Mann because his refusals to give it to you is infuriating? Or is this just a really good argument that you can use to pursue a political agenda? Please enlighten me.
Posted by: Andrew Dessler at November 15, 2005 12:08 PM
What Andrew said.
I think the debate is important because it highlights what the denialists have, and what they must do and say to make their argument (hi Jim).
That is: the M&M idea is the first thing to come along that has a ghost of a chance at actually being something real, as opposed to being simply made up, or conflation, cherry-picking, overemphasis of unimportant factoids (hello Han), etc. So it gets plenty of play wherever you turn, evidenced by the number of defenders that have already shown up here.
If these two can actually go out and write a real paper of their own [with data they collected and analyzed to make their point] showing how their idea is robust (I won't hold my breath), this debate may go somewhere. So there's a glimmer of hope for the denialists, but that glimmer is being trumpeted as a bright light. More than trumpeted - it is a big ol' brass band, with dancers and an MC.
But at this point, the only thing we have is a website with some rabid fans (hi, fFreddy), willing to flood the zone with the singular, tenuous arguments.
The debate is important because do we let arguments such as: "The request has been for the data and methodology used to get the results of a very important climate study." become policy. This is the core of that argument: MBH hasn't taken his valuable time to make his data available to the plumber down the hall! I'm curious to know whether at any point in the past a scientist was sternly denounced for not making his lab notes available for amateurs to look over.
When I see similar calls for Novartis, Stiglitz, all the Vioxx scientists, nuclear physicists, and other scientists and macroeconomists whose work " [a]ffects every man, women and child on the planet" to make their data available to the lay public, maybe then I'll be less...skeptical. There are serious questions about global macroeconomic policy. Better let the night watchman audit the World Bank's projections.
Arguments like these that the denialists rely on are why the debate matters - this is all they have. There is nothing else in their bag o' tricks: no models, no alternative theory, nada.
Posted by: Dano at November 15, 2005 01:09 PM
The back side of the moon is made of green cheese.
Posted by: Hans Erren at November 15, 2005 02:48 PM
Hmm, spaghetti graph, pastiche of climate reconstructions from a small group of authors who call themselves the “Hockey Team”. Should I repost to alt.troll?
Posted by: Eli Rabett at November 15, 2005 06:29 PM
"I'm curious to know whether at any point in the past a scientist was sternly denounced for not making his lab notes available for amateurs to look over."
Are you serious, Dano? If so, then what makes a scientific paper different from a fatwa or a Papal edict?
What is special about science is that it is objective and is grounded in emperical evidence. If we are jut supposed to take the word of Grand Poobahs, then we are talking about a religion, not science.
Posted by: Lex Spoon at November 15, 2005 07:14 PM
"What is special about science is that it is objective and is grounded in empirical evidence. If we are jut supposed to take the word of Grand Poobahs, then we are talking about a religion, not science "
Thanks for the religious references. That helps find the fear.
I'm still curious to know whether at any point in the past a scientist was sternly denounced for not making his lab notes available for amateurs to look over. Folk seem to want to argue that this statement means notes shouldn't be made available at all. This argumentation just helps make my initial point above, and thanks for that.
But anyway Lex, you - perhaps inadvertently - missed the point. Look and reflect upon the word 'amateur'.
The entire constructed narrative that gets disseminated by fans of the website arises from 2 amateurs huffy over someone not fully cooperating with them, and takes off from there.
I think perhaps we've learned from this that some data quality standards need to be enacted. That's what we have so far (I missed making that point earlier).
In every other matter, the debate over the robustness of their arguments continues and no conclusions can be drawn.
This despite the brass band trumpeting the premature touts, the distracting disco lights in our eyes, the confetti falling into the punch, and the MC purrrrring into the microphone about the quality and firmness of the pasta at the table.
I'll leave some bandwidth for other readers to talk about Roger's topic.
Posted by: Dano at November 15, 2005 07:54 PM
Amazing. Here we have two lengthy posts about "why the hockey stick matters" by each of the "M"s, and all we get by way of response is a chorus of "NO IT DOESN'T".
No defense of the IPCC's iconic use of the hockeystick? No defense of the Hockey Team's consistent refusal to disclose data or methods? It "doesn't matter" whether recent warming is unprecedented or not?
Posted by: James Lane at November 15, 2005 08:03 PM
re: iconic use of hockey stick.
The use of the hockey stick in the IPCC WGI report looks quite reasonable to me. It is only mentioned once in the summary for policymakers (bullet three under "An increasing body of observations gives a collective picture of a warming world and other changes in the climate system.") and in that bullet, it says that the hockey stick is "likely" true --- meaning, in their nuanced language, that there's an approx. 25% chance this statement is wrong. Considering that this was written in 1999-2000, that statement looks like it reflects the peer-reviewed literature that existed then --- which is what the IPCC's reports are supposed to do.
Individuals and advocacy groups might have used that plot extensively and misrepresented the IPCC's confidence in it, but that's hardly the IPCC's fault. Again, I can't help but feel that advocates are using this argument as a way of tainting the science to push a preferred policy position that is not supported by the vast majority of the science.
As far as the argument over why the hockey stick is important, I agree that it's important. As I said in my post above, I don't think it's important because the argument is over a crucial scientific point. It's important because it's become a political issue. And I note that in his post, Dr. McKitrick also doesn't argue that it's an important scientific question. He argues that it's important because MBH is iconic, peer review is sloppy, IPCC is sloppy, etc. Once we all agree that the actual scientific content of the question is not important, then we can move on to argue about the implications of the alleged "sloppy" science.
Posted by: Andrew Dessler at November 15, 2005 09:01 PM
"It is only mentioned once in the summary for policymakers (bullet three under "An increasing body of observations gives a collective picture of a warming world and other changes in the climate system.") and in that bullet, it says that the hockey stick is "likely" true --- meaning, in their nuanced language, that there's an approx. 25% chance this statement is wrong."
Could you explain how the IPCC assigns a probablility to this statement?
Posted by: James Laneq at November 15, 2005 09:13 PM
The authors of the relevant section of the IPCC read the peer-reviewed literature and assign a probability based on their expert judgment. That opinion is, of course, peer-reviewed by other experts, by member governments, and in a public review. This is described in footnote 7 of the IPCC TAR WGI SPM.
Let me know if you have any other questions.
Posted by: Andrew Dessler at November 15, 2005 10:37 PM
You have to be kidding me? It's all peer reviewed, so it's all hunky-dory.? You can assign probabilities of being "right" by some sort of arbitrary consensus? I don't think so.
MBH is shot full of holes. Innaccurate descrtiption of method, failure of R2 cross-validation statistics, non-robustness of sensitivity to inlusion/absence of bristlecones.
Yet the IPCC assigns this a "75%" correctness ( your words).
As a lay person (but strong on statistics), it doesn't inspire much confidence in anything else the IPCC has to say.
Posted by: James Lane at November 15, 2005 11:12 PM
Dano writes; "But anyway Lex, you - perhaps inadvertently - missed the point. Look and reflect upon the word 'amateur'.
The entire constructed narrative that gets disseminated by fans of the website arises from 2 amateurs huffy over someone not fully cooperating with them, and takes off from there."
I can understand a Creationist advancing 'ad hominem' and 'appeal to authority' (or lack of) arguments but I would have thought Roger's blog worthy of better than that.
"Why does the Hockey Stick Debate matter?" Because it touches on ever-present threats to good science - data manipulation, dodgy methodology and selective reporting in the name of a fashionable concensus and acceptance by those who publish and those who administer science funds.
Posted by: Michael Mayson at November 15, 2005 11:41 PM
I'll second Michael's comments. Steve McIntyre is a peerless statistician, and the argument about MBH is primarily statistical.
What really surprises me is that Dano knows this very well, and to cast an "amateur" slur seems well beneath him.
What are you on about Dano?
Posted by: james lane at November 15, 2005 11:57 PM
"In that bullet, it says that the hockey stick is "likely" true -"meaning, in their nuanced language, that there's an approx. 25% chance this statement is wrong. Considering that this was written in 1999-2000, that statement looks like it reflects the peer-reviewed literature that existed then --- which is what the IPCC's reports are supposed to do. Individuals and advocacy groups might have used that plot extensively and misrepresented the IPCC's confidence in it, but that's hardly the IPCC's fault."
Perhaps it was the fault of the Chairman of the IPCC, Dr. Robert Watson, who said in his Report to the COP6 meeting on November 20, 2000, that "It is UNDISPUTED that the two last decades has been the warmest this century, indeed the warmest for the last 1000 years" (EMPHASIS added).
Posted by: Ian Castles at November 16, 2005 04:08 AM
I'm taking a wild stab in the dark here, but I reckon that if they had been aware of any significant evidence to dispute it, they might not have said it was "likely" in the TAR. Of course, if you want to reserve "undisputed" for cases where no septic has ever disagreed, it wouldn't be possible to judge whether the Earth was round or flat. You can win a pedantry point for that, if you want.
Posted by: James Annan at November 16, 2005 06:57 AM
Responding to Eli above: In comparing the version I wrote with the one appearing here some editing happened after it left my hands. The last sentence of the 2nd paragraph now says: "A popular icon in paleoclimate circles these days is what can be called a “spaghetti graph,” showing a pastiche of climate reconstructions from a small group of authors who call themselves the “Hockey Team”. They agree on few details, other than that the Medieval Warm Period is not as warm as the 20th Century.".
What I wrote was "A popular icon in paleoclimate circles these days is what I [Steve] call a “spaghetti graph,” showing a pastiche of vaguely hockey stick-shaped climate reconstructions from a small group of authors I’ve [Steve] nicknamed the “hockey team”. Their apparent agreement is taken to be a kind of mutual validation."
I prefer my wording.
Re Dano's "I think perhaps we've learned from this that some data quality standards need to be enacted. That's what we have so far (I missed making that point earlier)." Data quality is hard to judge or specify in a set of rules. I'd settle for data and methods disclosure rules being enacted for papers that are being cited in debates over public policy, whether they are in economics or paleoclimate or elsewhere. And I'd like to see an independent government agency overseen by academic societies given the task of enforcing the rules and verifying reproducibility. As for being an 'amateur', we've been writing about statistical issues on which we're qualified. Journals like Nature require authors to make their data available to any interested reader, and I think there's good reason for that.
re Dano's point "If these two can actually go out and write a real paper of their own [with data they collected and analyzed to make their point] showing how their idea is robust (I won't hold my breath), this debate may go somewhere." Our 'point' is that the statistical basis for comparing the state of the present climate to that of 9 or 10 centuries ago is not strong enough to support the assertions of the IPCC on the matter. We have written real papers showing this, with data we collected and analyzed. The debate has gone somewhere.
Posted by: Ross McKitrick at November 16, 2005 09:15 AM
You object to the IPCC's providing expert scientific opinion about the hockey stick? How would you estimate our confidence in MBH? Would you interview 100 people at your local Safeway? Or perhaps you'd go to Circuit City to get a more "technical" crowd. The bottom line is that when you ask the scientific community for their opinion on issues of policy importance, the best you can do is to get a large group of experts to give you their opinion, then get that peer-reviewed by several other groups. If you think you know of a better way to get expert scientific advice, then PLEASE PLEASE PLEASE tell us all.
If your Watson quote is accurate, then it clearly does misrepresent our confidence in the hockey stick. As I said in a post up above, the IPCC's written report is, in my opinion, bulletproof. Any exaggerations are due to advocacy groups or individuals making inappropriate statements.
I continue to note that no one is seriously arguing that the hockey stick is an important debate scientifically. It appears that everyone agrees that it's import lies in what it tells us about the quality of climate science. I think this is an important realization.
Posted by: Andrew Dessler at November 16, 2005 10:20 AM
Thank you Ross:
I agree with your data quality assertion. In the argumentation I used re 'amateur', there are two parts to this, briefly: the expertise of statisticians is appreciated and the departments I was a part of had strong partnerships with the stats folk. The stats folk I know check stats, they don't presume to know more about certain plant communities than I do. Interestingly, some rabid fans want to use another curious form of argumentation, wherein statisticians know more about plant communities than I do (or, say, dendro than X); this lack of knowledge is surely inadvertent for some and deliberate for others.
The rabid fans of your (Steve's?) website take this message a few steps further, however, and appear to want to argue that data should be available for the janitor to mull while swabbing the deck. Janitors pondering spaghetti diagrams is not scientific integrity and thus the argumentation smacks of ideology or politics.
We all know if I have credentials and the PI has time, I'm likely going to get their data. All the hand-waving and disco lights attempts to distract us from this fact.
BTW, someone needs to fix this talking point if you're serious about your words - retroactively applying non-existant DQ standards and then stomping our little foot when they're not followed doesn't fly.
Re your 'point', I say again your assertion would be more robust and acceptable if you take a lovely fall walk in the woods, hunt for some yummy mushrooms, and core some trees while you're at it. The colors will be lovely. Talk about what you found while you fry up the shroomies [dry some for later so you can have winter soup while writing up the paper]. In my view, if you're serious about your words, this action will speak louder than your words and perhaps repair some damage wrought by the bad/ill-advised/no advice received tactic.
I look forward to hearing about what mushrooms you found, reading your paper and following the resulting discussion.
Posted by: Dano at November 16, 2005 11:00 AM
Just to clarify one point. Policy relevance in present Kyoto-type negotiations is surely not the only measure of scientific interest. People who are interested in climate history for its own sake can be legitimately interested in whether the Hockey Stick (or more generally the Hockey Team) has validly "gotten rid of" the MWP.
It seems that few IPCC climate scientists are interested in climate history for its own sake. Their interest seems to be whether climate history tells a story that helps sell climate policy. If it doesn't, then it appears that it "doesn't matter" to them. "Professionals" has more than one meaning. I actually have some interest in climate history for its own sake - which is a more complimentary interpretation of "amateur". I was interested in Bronze Age archaeology prior to being interested in climate and many archaeological events are attributed to climate change. I would be very pleased if some of my present research led to interesting results in this area, although I am far from being able to do this at present.
Contrary to Dano's characterization of our work, the principal conclusions of our studies on MBH pertain to the study itself; the lugubrious striptease of MBH methods and data is an entirely separate story.
I've always tried to make clear that I'm not arguing the larger issue of the impact of 2xCO2, although, to the extent that any detection and attribution models or other models are tuned on MBH99 or other multiproxy studies, there would be a knock-on effect. I think that this is possible, especially with Crowley and Hegerl's work, but have not specificially verified the point.
One of the key issues in our proxy research is how the statistics are handled. I don't think that I'm entitled to James Lane's flattering description (although it made me feel good); however, in the land of multiproxy climate science, I do view myself somewhat as a one-eyed man in the land of the blind.
Statistical issues relating to confidence intervals, spurious regression and autocorrelation in proxies are handled by multproxy authors, such as Mann and Briffa, in my opinion, incompetently. We've published examples from MBH and I've discussed many other examples in other studies at www.climateaudit.org, which I'll try to publish at some point. I don't see how anyone can describe the statistical practices of Briffa or Mann or Jones as "professional"; it would be generous to describe them as amateur. It frustrates me that people rely on this sort of tripe. I think that the authors must realize the precariousness of their work and this is one of the reasons for their stridency. Confident people would not place so many roadblocks in the way of the study of their work.
Anyway I don't want to give the impression that there is no scientific or statistical interest to the hockey stick. However in terms of the main policy issue, I recognize that the main policy issue of the impact of 2xCO2 can be argued without it. Our point here is that the level of due diligence and disclosure required for sound policy is much more than the casual due diligence of journal peer review and that it's always a good idea to do a post-mortem on mistakes.
Another point that we probably didn't make clear. IPCC scientists seem to take a narrow view of what an assessment report is: in their minds, the assessment report is simply a literature review and contains no independent due diligence. The public, on the other hand, seems to be unaware of these caveats and treats it as though it has carried out independent due diligence. They treat it more like a prospectus - using "prospectus" in its securities sense (i.e. the final offering to the public), not its science project sense (i.e. the project outline).
Most of you are probably not familiar with tort law, but there was a landmark case, Hedley Partners in the U.K. House of Lords, but applied internationally, which I think has lessons for IPCC. In Hedley Partners, professionals were held not to be able to contract out of due diligence obligations when third parties reasonably assumed that they would carry out due diligence. It would be interesting to consider IPCC obligations in such terms.
Posted by: Steve McIntyre at November 16, 2005 11:34 AM
I liked your post because it makes an important point: people do not understand the limitations of the IPCC (are you there, Mark Bahner?). The scientific assessment process is indeed an expert literature review. Assessments are predicted on the idea that due diligence is best carried out by the scientific community through the normal channels of publication and peer review. As evidence, just look at the recent GRL with your and several other articles. To me, that is due diligence by the entire community in action. Could the IPCC have done this good a job?
Expecting the IPCC to perform those types of analyses that are presently in GRL is impractical. How do you select which scientists vet hockey stick papers? Do you get MBH? MM? Both? Do you need due diligence on the people doing due diligence? Which articles receive due diligence? The idea is, in my opinion, both unworkable and much worse than the present system. But maybe you have an idea for a credible process that avoids these pitfalls. If so, please let us know.
Once people realize the limitations of the IPCC (or any assessment), I think a lot of this discussion will quietly go away.
Posted by: Andrew Dessler at November 16, 2005 12:24 PM
Andrew Dessler, Yes Robert Watson, Chairman of the IPCC, told COP6 in The Hague in November 2000 that it is "undisputed" that the last two decades of the twentieth century were the warmest for the last 1000 years. The statement quoted above is directly from Watson's report on the IPCC website at http://www.ipcc.ch/press/sp-cop6-2.htm
Posted by: Ian Castles at November 16, 2005 01:13 PM
Andrew, I'm not familiar enough with the processes of organizing a scientific prospectus to fully prescribe how to do things better. However, the principles of full, true and plain disclosure (including disclosure of adverse results) are always a good guideline and IMHO too little understood by climate scientists.
Given that the process appears to be no more than a literature review of articles themselves having undergone minimal due diligence, I think that there's too much undeserved self-congratulation on the wonders of the IPCC process.
The IPCC needs to state in a crystal clear way that it has NOT carried out any due diligence of its own and that journal due diligence is minimal. This would be obligatory disclosure in a securities prospectus. It should be stated in superbold characters in a prominent location in all summaries as it would be in a prospectus.
I think that there are some things to consider that would improve matters at minimal extra effort.
Data availability: I acted as a reviewer for IPCC 4AR and requested data for some unpublished studies. The IPCC WG1 Technical Support Unit refused to obtain it on the grounds that they were not going to do "secretarial" duties for me, although I would have thought that that was an obligation of a secretariat. I approached several authors directly who refused. The authors then complained back to IPCC WG1, who advised me that my contacting the authors was a breach of the confidentiality under which I was acting as a reviewer (as I presumably knew about the papers only through the IPCC review process) and that my duties as a reviewer were limited to ensuring that the IPCC text reflected what was reported in the journal, as opposed to carrying out any actual due diligence; and that if I engaged in similar further contact with authors, I would be expelled as an IPCC reviewer. I asked to appeal the initial refusal by the IPCC TSU past Susan Solomon, but this was refused. This doesn't seem like a very good process to me.
I don't think that authors should review their own materials. This is a recipe for problems. Even von Storch agreed with this in an earlier discussion of these issues on this blog. Someone mentioned on this thread that they couldn't think of any actual misstatements in IPCC TAR. Well, IPCC TAR incorrectly stated that the MBH98 reconstruction passed a variety of cross-validation skill statistics, which is false. If they had disclosed that the MBH98 reconstruction had a cross-validation R2 of ~0 and still achieved narrow confidence limits, everyone would have laughed at it.
I think that it would be a good idea to have some truly independent analysis of at least one of the big climate models - not by fellow travellers, but by competent disinterested engineers/scientists. It would take some time and would cost a little bit of money (but not much in the scheme of things), but it's the type of thing that helps reassure people who are worried that the modelers are trying a little too hard.
I think that a good airing of what people can expect from an international scientific prospectus is a really good idea and that climate scientists should support this. What better venue than the Barton Committee. They have a great deal of experience with public disclosure and due diligence. They are also an audience that scientists should be glad to attract. I don't think that people should be so quick to assume that they don't have a genuine interest in the topic. But they also don't want to be "promoted" - in the stock sense of the word.
In passing, I'm shocked that MBH made such saucy answers to them. In their shoes, I'd have made much more straightforward answers.
Posted by: Steve McIntyre at November 16, 2005 01:54 PM
Andrew Dressler wrote:
"I would also ask Mr. Clarke why the present debate, occurring in the pages of GRL, is not acceptable to those who doubt MBH? Will it not eventually get the correct answer? Do you want a stool sample from Mann because his refusals to give it to you is infuriating? Or is this just a really good argument that you can use to pursue a political agenda? Please enlighten me."
I think the real question is, Mr. Dressler, do you still beat your wife? At least I find that question as pertinent as the ones you asked me. I made no reference to the debate in GRL, but I also see no reason why we should limit discussion of reality to one particular forum.
I specifically said that no one wants a stool sample from Mr. Mann, (that the accusation was somewhat disgusting) and then explained what people were asking for and why. Your question is not only disgusting but illogical: "Do you want a stool sample from Mann because his refusals to give it to you is infuriating?" Since his refusal followed the request, it is very silly to argue that the request was initiated by the frustration generated from his refusal.
Propably the most common tactic used by someone loosing a debate, is to avoid the subject at hand and personally attack his opponent. When you question my 'political motivation' of a strictly scientific topic, I can only assume that your are loosing the argument.
Back to the issue at hand. I never said the 'Hockey stick' proved anything. I specifically said that, if correct, it would provide strong support to the assumption that CO2 is the main climate driver of Earth's tropospheric temperature. That is perhaps the most far reaching assumption of the IPCC report, and the most critical! If it is not true; if there are natural factors that have a comparable or larger impact on global climate change, then the IPCC report is hardly worth the paper it is printed on. If 'natural' factors are dominant, then there is no point in trying to predict future climate until we understand the natural factors.
In order for that assumption to be true, one can not have variable climate, similar to what we are experiencing today with increasing CO2, during times of relatively stable CO2. The assumption demands that relatively stable CO2 should result in a relatively stable climate and increasing CO2 should result in wider climate variability than stable CO2 concentrations. Conventional climatology (pre 1995) did not support the assumption, characterising such climate shifts as the Roman and Medievel Warm Periods and the Dark Ages/Little Ice Age cold periods all ocurring under (relatively) stable CO2 conditions.
Since the computer models operate on the CO2 assumption, they could not and can not model these climate fluctuations. The scientific process demands that the theory should be augmented to match the observations, but with climate change science, we continually find the observations being augmented to match the theory! The warm and cold periods long studied and accepted needed to be smoothed over to give the theory credibility. That is what the 'Hockey Stick' does. That is why the 'Hockey Stick' is so important. It supports the underlying assumption of CO2 as the primary driver of climate change, which is the bedrock of the entire theory and IPCC report! If it is not correct, and climate is naturally quite variable, the entire theory must be reworked and the calls to action are unfounded and detrimental.
If Mann et al are dismissing their study as being 'unimportant', it indicates that they have no concept of the issue at all. It is vitally important that we understand the variability of past climate before we can hope to predict the variability of future climate. The Mann study gave the theory some much-needed support. Without it, the magnatude of anthroprogenic global warming becomes little more than a scientific guess based on an unsupported assumption.
Posted by: Jim Clarke at November 16, 2005 01:59 PM
In the ClimateAudit.org discussion surrounding this call, I commented that, for the purposes of this debate,
1. M&M get to assume that their technical contributions are valid, but
2. they do not get to assume that the entire edifice of AGW therefore collapses.
From my outsider POV, I'm disappointed that the responses seem to be rehashing the technical and process complaints, which are well covered elsewhere, rather than explaining why policy makers should care, which after all was the explicit purpose of the debate. Icons and personality disputes aside, do CO2 emissions matter, after integrating all the evidence? And does the hockey stick debate affect the answer?
I think we might be starting to come to a consensus, though: McIntyre writes above that "the main policy issue of the impact of 2xCO2 can be argued without it [the hockey stick]", and Mann, in declining to contribute here, linked the RC "What if the hockey stick were wrong?" post. The consensus I'm hearing is "paleoclimate doesn't matter to policy", but perhaps this is premature.
(As an aside, hockey stick as icon is old school, so very 1998, with global tipping points being the new hotness -- for proof, see the article by some art prof in the Oct 27 Nature, the journal which best defines what's trendy and fashionable in science today.)
Posted by: TFox at November 16, 2005 02:07 PM
Re #3 - Steve Bloom. We wrote this article because we were requested to by Roger Pielke and not because we had any apprehension about the Comments and Replies at GRL. Our Replies were peer reviewed and accepted. We stated that both von Storch/Zorita and Huybers had failed to replicate essential aspects of MBH98 and this rendered their respective conclusions that the MBH98 errors did not "matter" completely meaningless.
We have fully answered every point in VZ and Huybers. In fact, I was reassured after the process simply because these two Comments failed. That does not mean that the correspondence is pointless; in fact, I think that it enabled us to state some points more clearly than in our original article.
I was irritated that realclimate publicized the Comments without describing the Replies and then refused to allow me to post up at realclimate rebutting the claims. This sort of defensive and petty behavior is all too typical of the Hockey Team and is one of the things that provides little reassurance to civilians and spectatots as to their confidence in their own results.
Posted by: Steve McIntyre at November 16, 2005 02:09 PM
TFox - paleoclimate comes into play in another way. The CO2 case ultimately is resting on models. Then the question is whether a given model can replicate a variety of earth periods. I'm not familiar with the ins and outs of all the models, which are coming fast and furious for the 4AR. I'm unaware of any model that can develop an ice age from little Milankowitch perturbations, although they seem to work a little better once they have an ice sheet. Here they cheat a little as the ice sheet seems to be classified as a "forcing", when from a Milankowitch point of view, it is surely a feedback on some scale.
I think that there's very considerable evidence for a warm MWP outside Europe, in the form of elevated treelines in the Polar Urals and Siberia and in the Rockies, and undoubtedly elsewhere. Has this modeled? I haven't seen any because there's such a commitment to the non-existence of the MWP.
I think that paleoclimate is instructive for tuning models. There's a considerable amount of effort being spent on this and this is commendable. I find IPCC tends to be a little too self-congratulatory to climate models and you have to read between the lines to see the pitfalls. I'd like a little les promotion and a little more candour.
Posted by: Steve McIntyre at November 16, 2005 02:21 PM
You write: "I also see no reason why we should limit discussion of reality to one particular forum." Absolutely right. You are free to discuss this issue anywhere and with anyone. But the real question is in what forum is the issue going to be best resolved? A blog like realclimate or cliamteaudit? I doubt it. The pages of a peer-reviewed journal is in my opinion the place where debates like this are most likely to reach a reliable conclusion.
Let me restate/rephase my question from my last post: do you think the scientific debate presently going on in GRL will (eventually) reach a robust conclusion about the relative warmth of the MWP? I'm curious what you think. If not, where should the debate be taking place in order to get the best answer?
As far as your argument about the scientific importance of the hockey stick, I'd point you to Steve M's quite reasonable response to TFox above. A knowledge of past climate variations is crucial for testing climate models, and clearly a knowledge of the MWP will help do that. But the argument that if the MWP was as warm as today, then humans are not altering the climate or the climate will not warm over the next century is unsupported by the scientific literature.
Steve: The best current thinking is that the little ice age was caused by solar forcing. There are observations that sunspots basically disappeared during that period, leading some to speculate that solar output decreased. If you assume that the sun dims, it's easy for a model to get a little ice age. Of course, we don't have any measurements of solar output from back then, so one must view that explanation with caution. But in any event, it could not possibly be orbital variations --- they are much too slow.
Posted by: Andrew Dessler at November 16, 2005 02:54 PM
Andrew, the "scientific literature" which purports to show that the MWP was cooler than the modern period is what's at issue here i.e. the hockey stick and its cousins. You can't simply assert that the "scientific literature" shows this, when we're questioning the validity of these studies. I'm not jsut questioning MBH; all of the Hockey Team studies are compromised by proxy selection and methodology. I made no attempt to argue this in the post, as there are many technical issues. But please don't assume that the proxy evidence of MBH or the other multiproxy studies (including Moberg) are sufficient to assert the point with any conifdence. That doesn't prove the opposite. However, I am intrigued by the evidence of higher treelines in the MWP in many different places of the world. This evidence is not considered by the Hokcye Team, but is very suggestive IMHO.
Posted by: Steve McIntyre at November 16, 2005 04:50 PM
I frequently wonder if I'm in the Twilight Zone.
Steve McIntyre writes, "IPCC scientists seem to take a narrow view of what an assessment report is: in their minds, the assessment report is simply a literature review and contains no independent due diligence."
Steve, it's far worse than that. The IPCC scientists have committed absolutely blatant--even admitted!--scientific fraud.
Look at these two statements. They're by James Hansen, the Father (or Godfather?) of global warming alarmism:
"Emphasis on extreme scenarios may have appropriate at one time, when the public and decision-makers were relatively unaware of the global warming issue. Now, however, the need is for demonstrably objective climate…scenarios consistent with what is realistic under current conditions."
“Also the IPCC predilection for exaggerated growth rates of population, energy intensity, and pollution calls into question the realism of their results.”
Or this statement by Stephen Schneider (also an IPCC TAR author):
"This sweeping revision depends on two factors that were not the handiwork of the modelers: smaller projected emissions of climate cooling aerosols; and a few predictions containing particularly large CO2 (carbon dioxide) emissions."
How can those three statements be interpreted as anything but an admission that the IPCC committed fraud with the deliberate attempt to alarm "the public and decision-makers"?
Posted by: Mark Bahner at November 16, 2005 05:35 PM
Steve - a quick comment before I post a full essay tomorrow, because this comment isn't relevant to that essay. You continue to call a loose group of guys the Hockey Team and you named in Monday's post "Mann, Jones, Briffa, Bradley, Cook, Schweingruber." This struck me as smacking of conspiracy mongering, so I asked a contact in dendro about these relationships. He is very well positioned to comment but wishes to remain anonymous considering the personal releationships involved. And he said, in essence (I'm paraphrasing, but I'll use quotes):
"He doesn't know that Jones might not get along with Ed [Cook] so well. Or that Cook and almost everyone else don't like Bradley. They'd hammer each other if someone did something foolish. ... He obviously doesn't know Ed 'tight-ass when it comes to analysis' Cook."
So in light of that insider view, I think your charactarization of a close-knit fraterinty of researchers patting each other on the back is off base. I think you're raising some good points, but this one isn't worth harping on.
MB - you are the classic troll: http://www.kuro5hin.org/?op=special;page=comments#trolls
take a breather. That horse has been dead for a long time and your shoulder must be getting very sore.
Posted by: kevin v at November 16, 2005 07:09 PM
Let's ensure the disco balls, brass band, and prolix authors don't distract us from our understanding that the MWP didn't have atm CO2 ppmv at today's levels.
Why _wouldn't_ today be warmer than the MWP with atm CO2 having been anthropogenically increased by a third-ish? I've seen no models, papers, graphs, IR iris diagrams, sketches, PowerPoint presentations, .avis, goat entrails, papyruses, Tarot results, nothing from the septics explaining this. Nada.
So asserting today is just another cycle as in the past, and this helps inform the future is, of course, problematic wrt policy. This is a policy site, after all.
It does nothing for society and policy-makers if we demonize scientists as...how are they characterized by the fans above...robed priests. With what will we inform our policy makers? Free market data? Oh, wait.
Lastly, let's not be distracted from the fact that the shocking, saucy pushback is reacting to a-holey behavior, not from fear over having vast funding sources cut, or a secret found out, or whatever talking point comes next. If I angrily scream - red-faced and spittle-spewing - at my GF, it's kinda dumb for me to argue *post facto* that she should sit quietly and answer me civilly.
We'd like for that to happen, but who expects it? I mean, other than those who tell us we should, else some findings are invalid.
So, that's another reason why the debate is important: keeping your tenuous tout in play means there's still some time to delay...
Posted by: Dano at November 16, 2005 07:20 PM
Mr. Dressler wrote:
"But the argument that if the MWP was as warm as today, then humans are not altering the climate or the climate will not warm over the next century is unsupported by the scientific literature."
Correct, but I was not making any such argument. The question is not and has never been about whether humans have an impact on climate or even if higher levels of CO2 have a warming affect. It has always been about the magnitude of these effects.
The models indicate that the effect is large and the results could be detrimental enough to warrant an immediate change in global energy usage; a task that is much easier said than done. The obvious question is, are the models accurate?
Perhaps the strongest argument that they are not (but certainly not the only argument) is that the models do not have the ability to reproduce past climate. But if the hockey stick is accurate, it provides the computer models with a connection to reality. It provided real world evidence that the CO2 assumption, on which the models are based, was correct. Namely that a relatively stable CO2 content coincided with a relative stable global climate, and increasing CO2 coincided with increasing temperatures. It presented physical evidence (not proof) that the virtual models might actually have some skill.
To say that the hockey stick is not important is disingenious. It was pivitol for the IPCC. It provided decision makers with a connection between the models and the real world. Most of the worlds population will never understand a fraction of the complexities of climate change, but the hockey stick made the point very clear and simple: 'the climate was stable until we started emitting CO2, and now it is warming.'
Take away the hockey stick and what do we have to connect the models with reality? Very little, and nothing that is easily grasped by the masses. In fact, reality generally indicates that the models are woefully insufficient and not capable of successfully predicting future climate.
I agree that the validity of the hockey stick does not prove anything either way, and the models can still be 'right' even if the hockey stick is 'wrong'. But our knowledge of climate change is far too tenouis to be speaking in such absolutes. What we are really doing is weighing evidence in order to make important decisions.
Take away the hockey stick and the only real world evidence that the models have skill is that global temperatures have erratically warmed while CO2 concentrations have steadily increased over the last 150 years. That may seem like a pretty strong argument until you consider that natural ocean, atmospheric and solar cycles do a better job of explaining the warming than CO2 does. Again, this does not indicate that increasing CO2 has no effect, just that its effect is much less than what the models indicate, and therefore, not a dire threat to the global ecology.
Lets face it, even if the latest recalibration of the satellite and balloon data are correct, they only support the minimum temperature predictions of the IPCC, and that is assuming that 100% of the observed warming is the result of increasing CO2; an assumption that is not supported by the evidence.
Aside from a flimsy coorelation to measured temperatures, the hockey stick was the only striking evidence that the models had skill. If it is not accurate, and past climate really was as variable as many suspect, than the evidence grows that the models have little skill.
It is not up to skeptics to 'prove' that the climate models have no skill. It is the responsibility of those who support the models to show that the do have skill, especially if they then ask us to reduce our lifestyles based on those models. If we should no longer count the hockey stick as evidence of the validity of the theory of significant man-made global warming, then there is little left. That is why the debate over the hockey stick is important.
Posted by: Jim Clarke at November 16, 2005 07:35 PM
you wrote: "the "scientific literature" which purports to show that the MWP was cooler than the modern period is what's at issue here i.e. the hockey stick and its cousins. You can't simply assert that the "scientific literature" shows this"
I'm not sure which statement of mine you're objecting to. If it's the statement that the IPCC represents the peer-reviewed literature, then I do believe it does. Remember that the TAR was written in 1999-2000, and the statements in the TAR were completely reasonable when it was written. I also think the statements in the TAR are properly caveated. For an expanded discussion of this, see my 11/15 9:01 PM post.
You wrote: "Take away the hockey stick and what do we have to connect the models with reality? Very little, and nothing that is easily grasped by the masses. In fact, reality generally indicates that the models are woefully insufficient and not capable of successfully predicting future climate."
I have to disagree with this. Most of the effort in evaluating the models is spent working on the last 150 years, for which we have (comparatively) excellent data. The models do a quite good job of simulating that period. e.g., see Fig. 12-7 from the IPCC TAR WGI report, and accompaying discussion. So, take away the hockey stick and you are left with an enormous body of work on validating the models over the last 1.5 centuries.
I also disagree with your statement: "Aside from a flimsy coorelation to measured temperatures, the hockey stick was the only striking evidence that the models had skill" for the same reason. It is not true because it ignores the efforts to model the last 1.5 centuries. This is not to say that comparisons against the MWP are not useful --- I agree with you on that point --- but comparisons vs. the hockey stick hardly constitutes a test that would falsify the models.
Ultimately, I still feel the hockey stick debate is of minor scientific importance.
Posted by: Andrew Dessler at November 16, 2005 08:37 PM
I was looking forward to your post on this, and it did not disappoint!
Here's my question to you: if the IPCC is such an obvious fraud, why was it endorsed by a blue-ribbon panel of the National Academy? And through policy statements of the AGU and AMS and AAAS? Is there a conspiracy afoot? Are you and Jesse A. the only ones who see the truth? Am *I* part of the conspiracy?
Posted by: Andrew Dessler at November 16, 2005 08:42 PM
Kevin - the term "Hockey Team" is not mine. If you google "realclimate hockey team", you'll see some provenance starting with perhaps http://www.realclimate.org/index.php?p=111. While the authors may squabble among one another from time to time, they have all coauthored leading multiproxy studies: Jones and Mann  and Mann and Jones  are not independent of Mann, Bradley and Hughes [1998, 1999] or Jones, Briffa et al  or Briffa, Jones et al  or Bradley and Jones  or Rutherford, Mann, Bradley, Hughes, Jones, Briffa, Osborn  or Bradley Hughes and Diaz .
Posted by: Steve McIntyre at November 16, 2005 09:18 PM
Could you please stop attributing statements to me that I didn't make? The only other James on this thread is Annan, and he didn't make those statements either.
Posted by: James Lane at November 17, 2005 02:26 AM
I think RPKjr’s position is that the hockey stick debate is a distraction from discussing real policies and is causing paralysis.
My position is that this is an intentional strategy. There are people and groups who oppose regulation of economic activities, and taken measures to insure that these laws are not enacted. For example the mining industry vehemently opposed the passage of environmental laws, and after the environmental laws were passed they fought to weaken them. As I have seen in my professional experience I know at times they attempt to ignore or subvert laws that regulate the mining industry.
The substance of M&M’s statements is not really about the science. The substance is about the regulations that are based on the science. To stop climate change regulations M&M are trying to subvert the science.
Posted by: Joseph O'Sullivan at November 17, 2005 05:18 AM
I think RPKjr’s position is that the hockey stick debate is a distraction from discussing real policies and is causing paralysis.
Posted by: Mr. Any at November 17, 2005 06:03 AM
My position is that Joseph O'Sullivan is trying to protect 'scientists' who don't show their work.
It took 300 years to replicate Fermat because he didn't publish his method. Do we have to do the same in climate science, or should we ask the scientists while they are still alive?
"Because Fermat refused to publish his work, his friends feared that it would soon be forgotten unless something was done about it. His son, Samuel undertook the task of collecting Fermat's letters and other mathematical papers, comments written in books, etc. with the object of publishing his father's mathematical ideas. In this way the famous 'Last theorem' came to be published. It was found by Samuel written as a marginal note in his father's copy of Diophantus's Arithmetica. "
Posted by: Hans Erren at November 17, 2005 06:04 AM
Hans, the relatively recent (early 1990s) proof of Fermat's Last Theorem by Andrew Wiles is one of the most remarkable accomplishments of recent times in my opinion. Wiles' methods are completely out of range for Fermat and it seems much more likely that Fermat didn't have a proof at all or maybe a proof that applied for n=4 or n=3, but not generally.
As an aside, 2005 seems to be the year that mathematicians have decided that Russian mathematician Grigori Perelman has proved the Poincare Conjecture. People have been considering his proof for about 3 years. Perelman has not published his proof in a peer-reviewed journal. For people interested in exotic uses of entropy, google "perelman entropy" and you'll find some very difficult papers. Cheers, Steve
Posted by: Steve McIntyre at November 17, 2005 07:33 AM
This column from the San Francisco Chronicle seems relevant to this conversation:
Posted by: Roger Pielke Jr. at November 17, 2005 08:57 AM
My apologies. I meant Jim Clarke. That's why they call it "dope."
Posted by: Andrew Dessler at November 17, 2005 09:21 AM
Roger, that Debra Saunders piece is quite thin on the specifics. In fact, it's quite close to sounding like something out of the home offices of Heritage or CEI.
Had a scientist spoken like that in public, would we, as in the past with statements thin on specifics, have received stern umbrage from certain policy bloggers, or would we have enjoyed a post on what and how that information could have been better stated?
Posted by: Dano at November 17, 2005 09:29 AM
Dano- Thanks. What are you wondering? Take Saunders' opinion as her opinion, not mine. It is a data point in how the skeptic issue is perceived by some. If you'd like another perspective, RealClimate has a post today, coincidentially enough, on skeptics and the media.
Posted by: Roger Pielke Jr. at November 17, 2005 09:50 AM
Your argument that the models have done well at modeling the past 150 years of climate has two major flaws. The first and most obvious is that climate has been around a lot longer than 150 years! If the models really grasp Earth's climate, then they should not be verifiable only to a miniscule portion of climate history. Perhaps you would argue that we only have 'good' temperature measurements for 150 years, to which I would say compared to what? Frankly, I think we only have good measurements for about 30 years, but we do have ample evidence of past climate and past climate change from many different sources for most of the Holocene and beyond. While not as detailed as satellite data, general trends (and that is what we are talking about) are certainly discernable through a perponderance of the evidence.
The biggest example of past climate change, the ice-age cycles, can not be predicted by the climate models. Atmospheric CO2 content appears to have been relatively stable while the Earth went through about 18 ice-ages and interglacial warm periods. With stable CO2, the models predict stable climate, not the roller-coaster ride of temperatures we believe to be reality.
The second biggest flaw is that scientist should go with the theory that best fits the data and not the one they desire to be true. While the planet has been generally warming for the past 150 years, nearly half of the warming occured when CO2 was rising slowly. When anthroprogenic CO2 began to increase more rapidly, global temperatures cooled, in direct contradiction to the theory. While plausable arguments for this cooling have been presented, they are not very compelling, and it still begs the question: how can any factor override the warming effect of increasing CO2 if CO2 is the primary climate driver?
While models based on AGW theory generally hindcast for 150 years, known natural cycles of ocean currents and solar activity combine to explain the observations even better than CO2! (These forces also explain the last 1,000 years quite well, while AGW does not.) Again, I am not suggesting that CO2 has no effect, but the evidence does not support the assumption that it is the main climate driver; the assumption on which the computer models are based.
I find it somewhat disingenious that the pre-1850 data is deemed insufficient to test the theory because it is not detailed enough, while the post-1850 data details are glossed over as being unimportant in comparison to the general trend. (Not an argument you made, but one that has been employed elsewhere.)
If you thought that Debra Saunder's piece was thin on the specifics, you should read the article she was referencing. It was a typical hit-piece on the skeptical view, complete with ad-hominem attacks and suggestions of corrupting influences, while totally avoiding any discussion of the facts or the arguments. While Debra graciously supplies her e-mail for comment, the authors of the original article where not so accessible. In an attempt to point out a few gross errors and misleading statements to those authors, I was rather dismayed to discover that they teach journalism to young, idealistic minds at Berkley. If they were teaching 'Techniques in Propaganda' it would have been more in line with the editorial they submitted. I found no evidence of journalism skills.
Posted by: Jim Clarke at November 17, 2005 04:19 PM
I have two thoughts:
I could go on, but there's a more important point to be made here:
your last post makes no effort to argue that the temperature of the MWP is of particular importance. I'm not saying it's completely unimportant --- everyone agrees that we want as much past climate data as possible to validate GCMs and to understand the climate in general, and the MWP is another data point. but it is clear that the situation is not, as you claimed in a post:
we clearly have a lot of data and research.
thus, I think it's clear that hockey stick is of minor scientific importance. so the question turns to whether it's important because it tells us something about the quality of climate science, the IPCC, etc.
Posted by: Andrew Dessler at November 17, 2005 09:15 PM
MBH defenders on this site often say that it is unreasonable to ask MBH for their "notes" and other details. I can see their point. So, since MBH will not address the problem of the bristlecones, among other criticisms by M&M, and since M&M have shown with complete openness that MBH's conclusions are not valid given especially the spurious bristlecone data, then the debate should be over. M&M should be the authoritative answer to the question whether it can be shown by these proxies that the 20th century is the warmest in 1000 years and that the 1990s was the warmest decade. This is clearly how science works. If someone can refute a claim such as that made by MBH, and the scientist making the claim is not able to overturn that refutation, then the claim was false.
Posted by: John Hekman at November 18, 2005 12:24 PM
"M&M should be the authoritative answer to the question whether it can be shown by these proxies that the 20th century is the warmest in 1000 years and that the 1990s was the warmest decade."
Sorry, M&M can never achieve such a status without relevant degrees, experience and peer-reviewed studies that are more than just comments on the work of others. My prediction is that McIntyre will get very little traction scaling up his attack to the entire hockey team.
Posted by: Steve Bloom at November 18, 2005 04:50 PM
Andrew Dessler writes, “I was looking forward to your post on this,…”
Posted by: Mark Bahner at November 18, 2005 04:56 PM
"M&M should be the authoritative answer to the question whether it can be shown by these proxies that the 20th century is the warmest in 1000 years and that the 1990s was the warmest decade."
By dint of what? Number of words written on a blog or in comments somewhere?
That's just your wishy-wish.
Posted by: Dano at November 18, 2005 06:17 PM
Oh, look: a Mark Bahner post.
How far do I have to paginate down before I get to content I want to read?
Posted by: Dano at November 18, 2005 06:18 PM
"...it's pretty obvious that funding for global warming research would decline significantly, if the ***truth*** about the likely very modest warming was widely known."
Not a chance. The fact that we are getting such obvious and worrisome symptoms out of the even more modest warming we've seen thus far creates much more of a demand for further research than existed in 2000. For example, the models failed to predict the current Southern Ocean warming that is having unfortunate effects on the stability of the Antarctic ice. Sounds like *more* climatology jobs to me, not less. There are lots of other examples.
Posted by: Steve Bloom at November 18, 2005 06:24 PM
Getting back to original question:
Its astonishing that many people here who argue for AGW now seem to believe that the MBH98 'hockey stick' is not important. It is VERY important scientifically as well as politically.
Taking the scientific points:
If the climate of even the past 1000 years varied significantly, possibly through variability in other factors such as solar insolation then LIKELY the present rise in temperature may be caused by the same natural factors. Anthropogenic contributions may also be contributing but HOW MUCH?
That is why the hockey stick is important scientificially - either you have an unprecedented situation (temperature flat for 1000 years followed by a steep rise) that you need a NEW factor to explain it (possibly AGW)
OR if the global climate of the past 1000 years has been much more variable and even been warmer ~800 years ago than now then MAYBE these natural factors are doing the same thing now and modern factors such as AGW contribute SOME, but maybe only minor amounts of warming.
If this was a debate on the precise value of the magnetic moment of the top quark then most people would not bother, but politically too this is huge to all of us since upon the whole question of whether we are doing something unprecendented to global climate hinges hundreds of billions of dollars, yen, euros etc of world economy. If natural effects dominate anyway and a medieval warm period or little ice age is going to happen to us anyway then we had better learn how to live with it and adapt.
Posted by: IL at November 19, 2005 02:10 AM
One thing that seems to have been hardly mentioned in this thread is the effect of the hockeystick on the public. The hockeystick chart, to the layman, is a powerful representation of dramatic and unprecedented temperature change in the 20th century.
As it happens, it was the hockeystick that first got me interested in global warming. I sw the chart on the front page of the Sydney Morning Herald, thought "WTF?" and started googling.
I, for one, resent having been "sold a pup", and I'm sure that many others (if they knew) would feel the same way.
Posted by: James Lane at November 19, 2005 04:10 AM
The supporters of the Hockey Stick don't defend it as being correct, they simply say it doesn't matter.
Here's a challenge for them. Stake your reputation and say that you believe the Hockey Stick to be 100% correct.
Or if, as you say, the Hockey Stick doesn't matter, it won't matter if you say it's incorrect will it?
Posted by: MarkR at November 19, 2005 06:45 AM
First of all my thanks to Roger are hosting such an interesting topic.
Dr. McKitrick raises some interesting points about peer-review, however I believe that he misses the bigger picture in terms of what the Hockey Stick Debate means for the future.
One of the interesting things about climate science, is that the field is broad enough for almost anyone to focus in on an area of their strength. Consequently, the field of paleoclimatology tends to attract those who are interested in fields such as statistics, and proxy indicators. However, my own view of climate science is based on my background in engineering and physics and thus from my point of view the Hockey Stick Debate does not matter.
I think we are approaching the point where we can measure greenhouse effect directly such as has been done by Rolf Philipona. He has two papers out that first discuss the direct measurement of downward shortwave and longwave radiation.(1) and another that looks at water vapor and in particular its source(2). While this work is restricted to central Europe, as we start to gather this information from over the globe it should become apparent what is the role of GHG in driving climate. This approach is independent of the results of the Hockey Stick Debate.
However I will add a specific comment on Dr. McKitrick’s emphasis on the Barton Investigation. While he seems to feel that this is significant from a science point of view, I feel that the facts actually show it to be a fairly crude attempt at directing hostility towards scientists who produce results that are not palatable to certain political stands. As I have argued on ClimateAudit the request from Barton was either poorly worded or excessively onerous. I find it highly unlikely that the wording was an accident, which would lead me to believe that it was based on political intimidation tactics. This is further backed-up by the amount of work that the committee has done since receiving Mann's and others responses. From a WSJ article at the end of October: “Mr. Neal said the committee staff hasn't yet begun a detailed analysis of the information it collected from scientists.” They received responses in July so they have been sitting on it for 3 months.
I would like to close with a personal observation. While the exchange often appears heated, I have exchanged e-mail communications with individuals from both M&M and the Hockey Team. Without fail, I have found these communications with individuals to be both helpful and courteous no matter which side of the debate they are on.
1) Radiative forcing - measured at Earth’s surface - corroborate the increasing greenhouse effect, GEOPHYSICAL RESEARCH LETTERS, VOL. 31, L03202, doi:10.1029/2003GL018765, 2004
2) Anthropogenic greenhouse forcing and strong water vapor feedback increase temperature in Europe, GEOPHYSICAL RESEARCH LETTERS, VOL. 32, L19809, doi:10.1029/2005GL023624, 2005
Posted by: John Cross at November 20, 2005 08:43 AM
That's funny, it diametrically opposes my historical findings:
Posted by: Hans Erren at November 20, 2005 02:09 PM
M&M share their code. MBH won't. Thereby asking to be taken on trust. M&M are true scientists in the Richard Feynman mold. MBH are academic poo-bahs and not real scientist-truth-seekers.
Posted by: TCO at November 20, 2005 02:55 PM
TCO, your 'real scientist-truth-seekers' is just constructed narrative.
Up until today, apparently, that tactic wasn't in your discourse mode.
In case anyone is confused, just because a researcher won't give information to someone trying to besmirch their name doesn't mean they are not real scientist-truth-seekers.
That's just hooey, at best.
Posted by: Dano at November 21, 2005 12:14 PM
It's the old bait and switch. Base your reputation on something, then when you're all sinecured, say that something don't matter no more. Man, it's a great scam if you can get it!
Posted by: Duno at December 20, 2005 09:15 PM
Re: “In case anyone is confused, just because a researcher won't give information to someone trying to besmirch their name doesn't mean they are not real scientist-truth-seekers.”
Arguable interpretation of why there is an RFI. But accepting of the premise, the information was supposed to be archived and available in the first place. And regardless of motive, what better way to demonstrate “robustness” – aren’t “robust” and “adversarial” in your dictionary? Would it be constructed narrative (bowing to your experience), to say that the besmirch-fearing researcher has either a shallow interest in being robust, or a disbelief in the adversarial system and the discovery process? What do you think Bürger and Cubasch ’05 meant by the term robust? Bürger, G., and U. Cubasch (2005), Are multiproxy climate reconstructions robust?, Geophys. Res. Lett., 32, L23711, doi:10.1029/2005GL024155.
As TCO pointed out, M&M make the information available. Ross McKitrick even fulfills information requests to Tim Lambert -- we all know Dr Lambert isn’t out to confirm any of Dr McKitrick’s results. I'd say that separates the two camps in terms of access policy in a rather obvious way -- wouldn't you?
Posted by: McCall at December 28, 2005 09:13 PM
Let's see if the hockey stick is a factor in this:
Will be showing periodically over the next days
The hockey stick was very prominent in this NOW:
I saw 30 minute episode tonight -- mostly spoke about "the consensus," the politics and the funding.. There was little/no science at all -- some ice cores and ocean temps (not much detail in either discussion). The was the (IMO) biased implication that government funded reasearch -- GOOD ... industry funded research -- BAD (or suspect).
Posted by: McCall at December 31, 2005 02:55 AM
re: "constructed narrative" and anyone's (TCO's for instance) "discourse mode."
One has to bow to your expertise on this subject as a leading poster of the "constructed narrative."
re: "because a researcher won't give information to someone trying to besmirch their name"
Perhaps one should add "robust" to your inquiry of definitions (e.g. "improper")? Setting aside your inflammatory and absurd implication, in your dictionary does "robust" have an escape clause for valid arguments made by "besmirching" statisticians in search of enough data for replication? Or worse, does the NSF now need to codify existing policy and procedure with exceptions of those judged not intending to "besmirch" the author? Was this exception covered in: Bürger, G., and U. Cubasch (2005), Are multiproxy climate reconstructions robust?, Geophys. Res. Lett., 32, L23711, doi:10.1029/2005GL024155.
While editing the dictionary and NSF's policies and procedures, make sure "hooey" gets a redefinition too.
Posted by: John McCall at January 1, 2006 12:53 PM