Click images for more details



Recent comments
Recent posts

A few sites I've stumbled across recently....

Powered by Squarespace
« Josh 27 | Main | McIntyre in Die Weltwoche »

Tamino on the Hockey Stick Illusion

Tamino has a rave review of the Hockey Stick Illusion up at Real Climate. I'm reading it now.

A few initial observations - there is a lot of discussion of proxy selection rules in Tamino's piece. This is complex for those who aren't embedded in the nitty gritty of the science, but stand back and ask yourself this: if you have over 100 series in your database, and one of these is the fourth most important pattern in the tree rings of a couple of closely related tree species in one area of the western USA, how comfortable are you that this series should form the basis of the temperature reconstruction for the northern hemisphere? The idea that you can reconstruct hemispheric temperatures in this way is deeply unsatisfactory.

Tamino doesn't try to defend the use of the bristlecones. It's not clear why it's worth arguing about PC retention if everyone (including the NAS and Wegman panels) agrees that bristlecones are inappropriate.

The observation that "McIntyre argued that the entire Gaspe series should be eliminated because it didn't extend all the way back to 1400" is wrong. MBH had its steps starting at 50-year intervals. Gaspe should therefore have been in the 1450 step not the 1400 one. There is probably an argument that Gaspe should be excluded because the update that was taken didn't show the same shape (although it was never published and everyone seems to have subsequently forgotten where the actual location of the trees is).

There's a lot of discussion of reconstructions being hockey stick shaped. The critical issue is of course the relative warmth of the medieval and modern periods.

Remembering Matt Ridley's article about straw men? I am criticised for complaining that hockey stick shape proxies dominate reconstructions and apparently I imply "unfairly" so. I explain how the hockey stick shaped series come to dominate the reconstruction, but I don't imply unfairness as far as I remember. Of course, since Tamino doesn't actually quote anything I said that implies unfairness, it's hard to respond in a precise way.

I'm accused of quote mining re the "better for our purposes" quote. Given that I start by saying that an innocent explanation is possible, I'm not sure this is reasonable criticism. I don't think it's a "killer quote" but it was there and McIntyre raised it in his correspondence with Nature, so it needed to be discussed.

There are very few quotes of any kind from the book (go figure), but certainly some I'd like to use on the cover of the next printing:

"A narrative worthy of the best spy thrillers"

"...spins a tale of suspense, conflict and lively action, intertwining conspiracy and covert skullduggery, politics and big money".

My publisher is going to love it.

PrintView Printer Friendly Version

References (1)

References allow you to track sources for this article, as well as articles that were written in response to this article.
  • Response
    Response: obawqcnc

Reader Comments (229)

My final words on the topic over at RC, now back to work!

Gavin, the post I made in #167 was a summary of Montford's book as closely as I can remember it, sort of a review. I did not particularly bring in my personal opinions into this, other than the framing of montford's points. So asking me to retract a point made in a book in a review of that book is, well, pointless. your attempt to rebut my points are full of logical fallacies and arguing at points i didn't make. As a result, Montford's theses look even more convincing. Once you'e in a hole, you can try to climb out or keep digging. Well keep digging, Gavin. My final words: read the book.

Jul 24, 2010 at 8:37 PM | Unregistered CommenterJudith Curry

This forum is such a rich font of wisdom allied to plain common sense. Thank you all.

The bottom line remains always that this whole furore is about warming of a degree or two or three in the context of a few pixel wiggles in the last fingernail-width 100 years of the following diagram, where we are already at an exceptionately late stage of an interglacial. Worry about warming, with concomitant increased crop yields and biomass enrichment countered by slight rises of sealevel, compared to the disasterous privation and extinctions resulting of another glaciation, seems to me to be an orgy of perverse logic.

Jul 24, 2010 at 8:41 PM | Unregistered CommenterPharos

Read Gavin's response to Judith Currie's comments at RC.

I'm not qualified to comment on the technical details of statistical analysis.

However, I am qualified to comment on human behaviour. It's truly odd that Gavin retains his position as a spokesperson for the warmist side.

Can't the people with normal interpersonal skills on his team (I'm sure there are some, right?) see just how incredibly off-putting this guy is!

I sure wouldn't want him carrying my team banner. With Gavin and that old smoothie, Al Gore, in sales their side is sure to lose market share!

Jul 24, 2010 at 8:55 PM | Unregistered CommenterPolitical Junkie

what is a tamino? I thought it was some kind of rodent!

Jul 24, 2010 at 9:32 PM | Unregistered Commentersunderland steve

Just for those who are still interest, Gavin posted the following at RC in reply to one of my posts:

"[Response: Sorry, I thought this was clear to you. No-one is interested in the non-climatic processes (at least in this context) - these involve residual age-related growth trends, disturbances, diffusion (in ice cores perhaps), bioturbation (in ocean or lake sediments) etc. These are the elements that might make one set of proxies, or an individual proxy record a signal that is not related to the climate. The long-term non-stationary part is of interest - that is the part that is related to some external driver (CO2, solar, volcanoes, orbital forcing etc.). This imposes auto-correlations on the proxy signal because there that exists in the drivers. The last part is also of interest - it is the internal variability of the climate system and should be at least regionally coherent. But its time/space structure is also complicated - variations in the North Atlantic causing temperature changes in Europe for instance will have auto-correlation too. The last two components are what we want to derive (though the distinction between the two is hard to define). So when you are testing methods against noise, you are modelling the impact of the non-climatic processes only and I guarantee that they are not best modelled as a red-noise process with the sample auto-correlation from real proxies. - gavin]"

Gavin has just made the elementary error of describing a process as having auto-correlation because it is non-stationary. I thinnk he is out of his depth on this topic and it shows.

Jul 24, 2010 at 9:35 PM | Unregistered CommenterThinkingScientist

Appreciations to Judith for her post, particularly while inconvenient for her. When she has more free time, her considered conclusions on the CRU inquiries would be most welcome.

My diag ref above, for reference' comes from an essay as follows

This site also has an interesting survey on socio-political affinity of scientists in the US

This site is relatively new to me so I am not yet in a position to judge it, just that the above are interesting.

Jul 24, 2010 at 9:52 PM | Unregistered CommenterPharos

TS,I followed your posts and Gavins responses with interest. I like the way you stuck to your guns but don't think that Mr S was as appreciative:)
I think he somewhat misjudged you at first which explains why his bluster increased with successive posts.
It was interesting to note that he's increasingly taking the line that we shouldn't get too hung up about Mann's original HS findings as (a) it was a long time ago and we've moved on since then (b) oodles of other studies come to the same conclusions anyway and (c) anyone who questions the consensus has clearly not done their homework!
In his head, I suspect, that correlation is sufficient to prove causation when it suits ones belief.

Jul 24, 2010 at 10:13 PM | Unregistered Commenterroyfomr


Gavin's final replies to my last post show clearly to me that he has argued himself into a corner and either does not understand what I have been pointing out to him or now realises that his argument does not stand up. He has contradicted himself several times and provides lengthy and verbose responses to simple questions without answering the original question directly.

More imprtantly it has shown me something very interesting though which is the claim by WahlAmman2007 to refute the red noise test by saying it contains the "climate signal" is an assertion, it is not supported in their paper or anywhere and Gavin has failed to answer my points. It opens up an interesting area of analysis for me.

Jul 24, 2010 at 11:20 PM | Unregistered CommenterThinkingScientist

I apologise for bringing the Bish site into disrepute but I have posted on RC :(

Hello folks :)

The whole of this argument is really about CO2 and what it does or does not do to our planet.
Just before this interglacial levels of CO2 in the atmosphere dropped to 250 ppm. The estimated lowest level of CO2 required for vegetation to survive is 220 ppm.
During the last 2.5 billion years of climate history we know that levels of CO2 have been as high as tens of thousands of ppm but have been falling through the whole of the 2.5 billion years.
The Earth is under far greater threat from falling CO2 than from rising CO2.
A rise of 15 degrees C from todays temperatures would be highly inconvenient for many millions of human beings but that is only because we built our society and infrastructure during the rarest and most short lived climates the Earth ever experiences… an interglacial.
During the last 2.5 billion years the Earth has spent only 1% of that time in interglacials and already this interglacial is longer than most.
Should the world continue to warm even by as much as 15 degrees C it would simply be returning to its normal state (80% of the 2.5 billion year history)
Trying to take CO2 out of the atmosphere right now is lunacy.
Warming 15 degrees C would mean a lot of people moving house but would be survivable.
Should we return once more to an ice age (and the current solar minimum is not a good sign) then your wind farms will be useless and people will wonder why we did not spend money trying to prepare.

Jul 24, 2010 at 11:21 PM | Unregistered CommenterDung

Judith, awesome. Many thanks.

Jul 24, 2010 at 11:29 PM | Unregistered CommenterJosh

I am hoping that Judith Curry is beginning to see the modus operandi of Gavin, Tamino, and the rest who are firmly committed to their views and are closed to any other interpretation or mechanism other than Co2. Gavin (the black knight) has never let any of my posts past his "bridge". It is shameful and ultimately harmful to their views to not allow civil debate. Openness and clarity shall win the day. Rudeness, contempt, and especially censorship add water to an already slippery slope. I understand how parts of our climate operate, but the entire enchilada is still beyond our grasp. I enjoy the search, and read as much as I can on the subject (from both sides). The only definitive conclusion I have come to is; jeez we have a lot of work to do yet.

Jul 25, 2010 at 12:03 AM | Unregistered CommenterDavid Ball

TS, good luck on your journey. I distinctly took away the impression, from RC,
that it would be no mean task to shake you off,once you've determined a course of action.
It wouldn't surprise me if, at some time in the future, your "red-noise" probings turn into "red-mist" issues for dear Gav!
Best wishes and thanks.

Jul 25, 2010 at 12:09 AM | Unregistered Commenterroyfomr

A very educational set of exchanges. Particularly amusing to see the RC climatologists argue that the _removal_ of the lonely series that yield the hockey stick would constitute 'cherry picking'. But much kudos to Judith, Thinking Scientist, Atomic Hairdryer, and others for keeping so much work from happening on a Saturday. I appreciate Gavin S. too though he is clearly misplaced as a climatologist - such talent should really have found an outlet in the legal profession.

Jul 25, 2010 at 12:22 AM | Unregistered CommenterZT

Don Pablo de la Sierra wrote:

Why did the Hockey Stick become such a powerful icon? IT IS VISUAL!!!!

Over 99% percent of the people don't read, they look. That is particularly true of politicians. Just look at all the totally stupid and counter-productive legislation passed in the US Congress. Ask them if they read the bills and they give you a dumb look. Only the Irish Dáil has done worse.

We need VISUAL icons as well.

I’ve come up with a powerful and aggressive visual image: a pair of upraised hands decisively snapping a hockey stick (with its blade upturned at the right). It is based on the well-known (to warmists) logo of the War Resisters League, in which the hands are snapping a rifle. A large, easily readable caption around the perimeter of the button would read, “Gore Resisters’ League.”

It's a clear, clever "grabber." (It would work for T-shirts too.) I donate this idea free to any climate contrarian group that would like to sell and/or give it away as a way for people on our side to identify themselves and give a Bronx cheer to the climate consensus. Button-makers can be found on the Internet under “Custom Buttons.”

Following my suggestion, a kindly blogger named S. Weasel has created an image that comes close to my vision, here (then hit page-down twice):

But the caption around the perimeter is too small and fails to capitalize on the play on words involved in changing only the initial consonant of the phrase. (Also, the pair of hands should be redrawn so as not to be a direct copy of the hands on the War Resisters’ logo.)

Jul 25, 2010 at 12:28 AM | Unregistered CommenterRoger Knights

PS: Anyone who'd like to use that stick-snapping image on a book-cover is also free to do so.

Jul 25, 2010 at 12:35 AM | Unregistered CommenterRoger Knights

As one who was a little sceptical of Judith Curry's first entry to the climate blogosphere debate some time ago I offer unreserved compliments on her continuing efforts to put simple science ahead of politics and prestige.

She is a very worthy addition to the small band of those practising professionals with the intellect and courage to put their heads above the parapet to face down the wrath of the seduced, gullible or cowed "consensus".

Jul 25, 2010 at 1:11 AM | Unregistered CommenterAlan Wilkinson

Warmists even more pissed with Judith Curry's support of Montford:

Jul 25, 2010 at 1:29 AM | Unregistered CommenterHockey Schtick

Lots of head scratching over RC here. Some posters in this thread pinned it early (e.g. Shub). The intent of RC is to provide a scientific-sounding response to the critiques of the skeptics that are convincing enough for a large majority of the people pointed their way. RC has tons of links into it stating that it is the best source for scientific discussions so they are attempting to portray that image while not allowing their major points to be rebutted.

The main responses that Mann and company now allow are noise (inc tangents), rudeness, and ad hom attacks as long as they are pro-alarmist. Perhaps some over-the-top alarmist comments get censored, it's hard to tell. An essential type of challenge that they allow is the naive-skeptic-with-talking-point. Those are quickly and fairly effectively shot down by the RC regulars but are essential to give the appearance of openness. They allow almost any numbers of follow-ons by the naive skeptic as long as they ask easily answered questions. They also allow Curry's #168 challenges as shown in the current thread but only under the conditions that the thread is destined to reach many hundreds of comments because they know that those will be lost in the noise and will be portrayed as hit and run and/or giving in to their superior science (e.g. #189).

Gavin is obviously willing to spend considerable time and energy on responding to #168, yet essentially admits in #185 that he hasn't read the book and isn't going to. That should clearly tell us that RC is intended to portray an image rather than perform in depth analysis on the particular topic, no matter how loose and unscientific the hockey stick book might be. The category of challenges that get censored are in these and smaller threads with simple and direct contradictions to the thread's major topic. As a thread grows in size they can allow more of those in because those will be overwhelmed by the chaff, tangents, ad homs. He can admit that no single paper is perfect without having to discuss the imperfections which are always old news. Or he can get any number of his regular posters to post that for him.

Obviously there are also sincere attempts to defend the science and style at RC but those are overwhelmed by the noise from 190 and on. It is quite amazing to compare Steve M's censorship and the lack of censorship of the piling on in his threads. But it meets the goals of the site which is to provide overwhelming evidence to the untrained passerby that the (hockey stick) is rigorous science despite a few imperfections in some early papers.

Jul 25, 2010 at 2:02 AM | Unregistered CommenterEric (skeptic)

@Thinking Scientist
"My comment got through but not without edits.

Want to know what was edited? All references to Bishophill, CA and WUWT websites. Its like being in Harry Potter - He Who Shall Not Be Named."

I find this absolutely despicable, not to mention fundamentally disturbing. I consider this to be a moral crime. It is bad enough if one is simply censored completely, however to have one's comment actually edited to change its meaning is one of the most shameful acts one can do online and casts severe doubt on the perpetrator's actualy concern with anything resembling the truth.

Jul 25, 2010 at 2:23 AM | Unregistered CommenterKatabasis

It was a sad day when I found out the geniuses at RC think I am a buffoon...


Jul 25, 2010 at 3:11 AM | Unregistered CommenterKen Coffman

I wouldn't worry unduly, Ken.

Real Climate is as little renowned for a sense of humour as it is for fair play.

As Katabaisis rightly says its habitual editing and censoring to deliberately misrepresent is a moral crime, fortunately entirely counter-productive. Mocking it is ethically effective.

Jul 25, 2010 at 4:07 AM | Unregistered CommenterAlan Wilkinson

Sounds like Tamino is really, really sorry about writing that review. I have just returned from my -- hopefully last -- visit to Troll Land. It was fun reading, from a psychological view point. Clearly Judith Curry, Jean S, Thinking Scientist and Atomic Hairdryer did superb work in running both Tamino and his faithful side kick, Gavin, in circles on their own territory. That is the amazing part. The four of them, plus a couple others, invaded AGW Gruppenführer's private fiefdom, blew through their attempt to be in control and ran amok with reason, logic and fact.


While the Faithful still bleated like sheep, it was very interesting to read several of the "not-quite-sure" followers who now have doubts. That was where Tamino and Gavin did the worst damage to themselves. Many in the congregation now has doubts.

Roger Knights

I love your idea of breaking the Hockey Stick. It has an image that is particularly compelling.

And I might add Bishop you might consider writing a book about the fall of AGW. You could use Breaking the Hockey Stick as the title. You certainly have a ton of material to use already and we are just starting on the fall of AGW. It may take a year or so, but my guess is the IPCC Mexico City meeting will either not happen, or will occur behind locked doors in the broom closet. Just a guess, but I see momentum building.

Perhaps Josh could come up with an image of two hands, shackled with chains, but the chain broken, snapping overhead the Hockey Stick that is on the cover of HSI. It must be recognizable as the Mann Hockey Stick. Then we could have a contest with coming up with a motto. I know that there are several of you out there who are very good at that sort of stuff.

I like "Breaking the Hockey Stick" myself, but I am sure others can do better.

Alan Wilkinson

As one who was a little sceptical of Judith Curry's first entry to the climate blogosphere debate some time ago I offer unreserved compliments on her continuing efforts to put simple science ahead of politics and prestige.

I was once skeptical as well of her. And I too am fully won over and also offer my unreserved compliments. Good Job, Judith!

Thinking Scientist

Gavin has just made the elementary error of describing a process as having auto-correlation because it is non-stationary. I thinnk he is out of his depth on this topic and it shows.

While I haven't messed with statistics for 40 years, and I do not know Time Series Analysis as it was invented after I stopped playing with statistics, even I know better. Gavin is an ignoramus when it comes to statistics. That is very clear. Like Jean S, I am sure I would have flunked him in my statistics course. However, when you look at his "scientific method" it is little wonder that his statistics are a total joke.

By the way, excellent job of burrowing in like a tick and chewing on his knowledge. You can be relentless when you wish to be.

Jul 25, 2010 at 4:28 AM | Unregistered CommenterDon Pablo de la Sierra

Seems like my last comment on the issue got stuck to RC moderation queue for indefinite time. Here it is:

Jean S says:
Your comment is awaiting moderation.
24 July 2010 at 2:45 PM

Tamino: ” Jean S first says “the use of “Preisendorfer Rule N” is not described in MBH98 (or related literature).” He’s proved wrong.”

This is pathetic. What part of the word “use” you did not understand? MBH9X did not describe the use of Preisendorfer rule to tree ring selection anywhere. Instead the only short sentence (and the fact that the rule is not found in the released PCA code) about the issue leads one to believe that no objective rule was used, and the evidence shows that at least Preisendorfer rule N was not used consistently for all tree ring networks. It makes little sense to use it only for some networks.

Tamino: “First he says “Tree ring series are already in common units.” He’s proved wrong.

They’re dimensionless, each being scaled by its own mean, hence the mean of each series will profoundly affect the size of the variation — exactly what’s to be avoided. AND they’re not even describing the same thing, some are ring width data while others are ring density! Even if they weren’t dimensionless they couldn’t be in the same units.”

This is pathetic. You are sticking to the literal meaning of _my_ words “common units” without bothering to consider meaning/science behind them. When did my words become such gospel to you? The series (variates) are supposed to describe the tree ring growth, and in this sense they are in “same units”, and there is no reason for correlation PCA, and therefore one should use “standard” (covariance) PCA. However, among other things and as you observe, series are _divided_ by the mean, and it would be advisable to log transform the series. Followed by covariance PCA.

Jul 25, 2010 at 8:01 AM | Unregistered CommenterJean S

The defense of the hockey stick is moving beyond absurd. I remember JeanS writing 'Garbage' of Tamino's earlier defense of the hockey stick at 'The Open Mind', and I was witness to Tamino's banning of him immediately. I saw Ian Jollife chime in, months later, and run rampage sedately over Tamino's thesis.

So why does he keep his needle in the groove despite the increasing cacaphony? There is more than ignorance here; nor can this be explained by disingenuousness, What is the motive?

Sometimes I wish I didn't ask.

Jul 25, 2010 at 8:04 AM | Unregistered Commenterkim

@David Ball re The Black Knight. More like the knight guarding the bridge in Monty Python and the Holy Grail.

Jul 25, 2010 at 8:13 AM | Unregistered CommenterRayG

Struggle through to Comment #236, it is priceless; dhogaza responding in detail to jo abbess.

Jul 25, 2010 at 9:06 AM | Unregistered Commenterkim

Eric said,

Gavin is obviously willing to spend considerable time and energy on responding to #168, yet essentially admits in #185 that he hasn't read the book and isn't going to. That should clearly tell us that RC is intended to portray an image rather than perform in depth analysis on the particular topic, no matter how loose and unscientific the hockey stick book might be.

I would add that that image also depends on Gavin's own image as a sort of all-knowing, all-competent "climate scientist" who can answer any question thrown at him, and thus reassure the RC crowd. That implies never, ever, conceding that he might be wrong and that the skeptcs might have a point, which is also the game Tamino plays. Of course that has the consequence of making them look absurd when they genuinely don't have arguments nor know what they are talking about, but they must maintain the pretense for the sake of those who can't really follow the arguments but would spot any sign of "weakness" in them.

In the long run, of course, this has the effect of turning away the more intelligent readers who can see through their bs, leaving them only with the "please reassure me I'm not wrong in believing you Gavin" crowd. The reason neither Gavin nor Tamino realise that is, I think, that they genuinely believe that the vast majority of people are far less intelligent than they are - this trait of Gavin's became obvious during the intelligence-squared debate.

Jul 25, 2010 at 9:53 AM | Unregistered CommenterPeter B

Forgive me if I am stating the blindingly obvious. but the discussions at Real Climate remind me powerfully of the hatred and bile engendered by the 'Left' during my time at University. Especially to each other.

And I note also that though not an exact contemporary of mine, Gavin Schmidt was an undergraduate member of my college while studying Maths. Possibly even at the same time that John Houghton was a Fellow. It is only a small college (400 members). Apologies for them both on behalf of the rest of us.

Judith Curry is clearly suffering the fate of the apostate in any true religion...its a wonder that RC hasn't (yet) called for her severe and painful physical chastisement.

But Monty Python (often so relevant to the climate 'debate') satirised them even before their time

Jul 25, 2010 at 9:58 AM | Unregistered CommenterLatimer Alder

I can no longer find any of our posts on the Tamino thread, have they moved them or do I get my white stick out

Jul 25, 2010 at 11:15 AM | Unregistered CommenterDung

Ah I found them. It seems that at the bottom of the article you now only get the option of a popup window showing responses, we dont seem to be in that. However you can select INLINE RESPONSES from the right hand menu and we are in that. Well you peeps are, my response was moderated out :(

Jul 25, 2010 at 11:30 AM | Unregistered CommenterDung

Typical! As if it never happended. I wonder what they feel about this in a rare moment of self contemplation?

Jul 25, 2010 at 11:36 AM | Unregistered CommenterBarry Woods

There are quite a lot of posts complaining that we were ever allowed into their forum at all. The basis for this is apparently we are all so dumb that we spoil the intelectual atmosphere of their forum, it is not because they fear criticism it is that we were not worthy to criticise ^.^
Well I may not be worthy but most of you guys are more than worthy :)

Jul 25, 2010 at 12:37 PM | Unregistered CommenterDung

I noticed during the height of the debate over at Realclimate that 1st they didnt seem to understand what Steve and the Bish were both trying to achieve and 2nd that they dismissed any criticism of the Hockeystick because that is now old hat.

Steve has not taken sides in the AGW debate.
Steve does not claim to be an expert in climate science.
Steve just digs around in stuff that does not seem to make sense to him.
Steve wanted to dig into the Hockeystick and if Mann had been open about his methods? Well then we would not still be talking about it.
The time it took for Steve to get to the bottom of the cesspit made it an epic story.
The Bish simply told that story.

Jul 25, 2010 at 12:51 PM | Unregistered CommenterDung

I posted this at RC. Let us see how long it takes to appear


"(I lost the conservative, fundamentalist Christian bits as I became an adult, but my mother’s condemnation of dishonesty is a lesson I’ve never slacked on)"

You mean, you never gave up on relentless moralizing.

"They walk among us as embodied reproaches, as warnings to us - as if health, well-constitutedness, strength, pride and the sense of power were in themselves necessarily vicious things for which one must pay some day; how they crave to be hangmen. There is among them an abundance of the vengeful disguised as judges, who constantly bear the word "justice" in their mouhts like poisonous spittle, always with pursed lips, always ready to spit upon all who are not discontented by go their way in good spirits"

The last time, you took the same 'high route' approach was with Oppenheimer's Science magazine article at Collide-a-scape.

Why do you hang on every word she pronounces on comment sections - for instance, do you believe she just expressed her full spectrum of opinion with her long comment above? I doubt that she is on any metaphysical cusp, seeing as that she's been reading climate blogs for some time now, but as Jo Abbess points out, she is willing to engage, and all you can offer is that she conform to your sense of honesty?

I read her comment (available in its entirety and continuity, at Bishop Hill) and I came away with a different message, probably closer to what she wanted to convey. She lists some of the issues raised in Montford's book and then offers her opinion that these issues have be tackled positively and head-on. If Tamino and Gavin seeks to discredit the book, by saying these issues are non-issues, to an observer, it is clear that 'engagement' has not occurred and therefore their opinions on Dr Curry's understanding of the situation have not much of value.

Jo Abbess: Maybe skeptics assume the genial, fun-loving, gentle tone simply because that is the only moral tone and space available to them? The shrieking, moralizing, judgmental tone of finality and certainty - of every color - has been assumed by climatologists (scientist and advocate alike). Apparently they do not have the time, since they are privy to some revealed 'truth', for their fellowmen to catch up them or be educated by them - it is no surprise then, that those skeptical of a few aspects of AGW are driven to suspect the whole enterprise.

Monckton is, for example, belligerent and aggressive. See how that raises the blood pressure of AGW proponents everywhere. I would scarcely imagine that it is wholly due to objections to his 'science' alone - it is more likely due to an impression that only the establishment can don the patina of climate-righteousness which Monckton usurps.

Therefore some PR advice to a PR person - if you want to 'discredit' skeptics, you should drive them into the moral space, self-righteous warmists occupy today - a project I doubt would be anything easy at all.


Jul 25, 2010 at 1:15 PM | Unregistered CommenterAnand


Good points. As a side, I must admit that whenever I see "Dhogaza". I read it as "the Hogzilla". I must need new glasses, but his attitude does little to change my reaction to his nom de plume.

Jul 25, 2010 at 3:45 PM | Unregistered CommenterDon Pablo de la Sierra

I am a layman trying to get my head around this hockey stick thing. I have been following the climate science debates on various blogs for a while but am not entirely clear. I wonder if I might ask a few questions, in particular about the suggestion that the algorithum (is that the right word?) that Mann used will produce a hockey stick if red noise is used instead of data. My questions are these;
Is the above true?
What is red noise (in simple terms please)
Does it always produce a hockey stick for every run with red noise, or for only some?
Does the blade bit of the hockey stick always appear at the end of the run or can it appear in the middle of the run?
Is the blade of the hockey stick the same size with the red noise as it is when the data is used.

Thank you for taking the time to answer. I am going to ask the same questions at Real Climate to get the view of the other side.


Jul 25, 2010 at 5:23 PM | Unregistered CommenterFred Windsor

Peter B said "In the long run, of course, this has the effect of turning away the more intelligent readers who can see through their bs, leaving them only with the "please reassure me I'm not wrong in believing you Gavin" crowd."

I have noticed a few of their former readers on other boards who still want to believe the BS but think that RC is too elite or off putting. In other words, they don't quite see through the BS but sort of realize it might be. So they might read John Cook's site instead.

Jul 25, 2010 at 5:25 PM | Unregistered CommenterEric (skeptic)

Fred :)

There are far more knowledeable people than me on both websites and hopefully they will give better answers than me.
However I think what I will say is true:
The creator of the Hockey Stick refused to disclose his data and methods for at least 5 years and some say he still has not come clean. To me that is offputting.
Red noise is basically random data (there is still an argument about whether the red noise put through the hockey stick model really was random but I believe it was and it is easy to reproduce.
When red noise/random data was put through the hockey stick model by Steve McIntyre (10,000 times) it always gave a Hockey Stick.
The uptick (blade of the Hockey Stick) is always at the end.
The Hockey Stick model is wrong for a number of reasons:
1st The random data test as above.
2nd it contains tree ring data. Tree ring data is very unreliable as a proxy. When you take a sample from a tree and study the width and density of tree rings it is assumed that this is a signal of temperature. Wide, dense rings = warmth, narrow rings = cold.
Recent tree ring data also shows that they must respond to other things we dont know about.
Tree ring width/density is known to rely not only on warmth but also moisture and CO2 (which is a powerful plant food).
However recently some sites studied for tree ring data have shown narrowing of tree rings even though we know that temperature has been rising and CO2 has been rising. This has been happening now for about 30 years at least.
Tree ring data should not be used to indicate historical temperature because we can not be sure that tree ring width does indeed indicate warmth or cold.
3rd the statistical methods used to produce the Hockey stick have been attacked by a number of talented statisticians.
The accusation being that the model is designed to give a Hockey Stick whatever data is put in.
The explanation of this is contained in the first 2 chapters of "The Hockey Stick Illusion" and is much better than I could give :)

Jul 25, 2010 at 6:02 PM | Unregistered CommenterDung

As of now, my comment, posted above here, has not appeared. Many other posts bashing Dr Curry have appeared. I post with my real name at RealClimate. To any observer, what will it look like? It will appear as though Dr Curry has no points in her favor, has no one to speak for her, or share her outlook.

Any argument, any point and counterpoint, in online discussions, has a certain lifespan. Every argument peaks in intensity, claims and reverses are made within that period. If you control your opponents' claims/points from even appearing, but allow your side of the team - you have already taken your activities into the realm of advocacy as a scientist (apart from such a thing being the most detestable vileness you can encounter ).

What a bunch of losers.

Jul 25, 2010 at 7:16 PM | Unregistered CommenterAnand


What Dung said is generally quite correct, but I will try to give it a bit more meat for you to gnaw on.

What we think of as "static noise" is generally random frequencies with random amplitudes. It can be characterized in many ways, but is often discriminated into categories with names from the colors of the rainbow. I think it would be best if you went HERE and listen to it yourself. Red noise is also Brownian, which has nothing to do with the color Brown, but refers to the name of the scientist that described "random walk" of particles.

Now on to the test. Brownian movement is key to a number of statistical models, most specifically Time Series Analysis, which was (ab)used by Mann, Jones and others. There was a long and wonderful blog about all that in which a very knowledgeable statistician named VS patiently tried to explain it all. However, there is the old saying of "don't try to teach pigs to sing because you will only waste your time and annoy the pig" and from what I saw from Tamino and Galvin, he was wasting his time. But I digress.

What Steve McIntyre did was to take the "data correction" code used by Mann, Jones and others and when passing Red Noise through it, he got a hockey stick. He should have gotten a flat band of data. That is the Red Noise should have remained relatively unchanged from start to finish, but it mysteriously goes up hill at the end. That is VERY WRONG! And suspicious.

Now to return to VS and his lecture series -- he showed that the data Mann, Jones and others used to get their Destruction of Earth results had something called a Unit Root. That is very complex to explain unless you go into matrix algebra, but it suggests that the mean and variance of the data being used varies over time. The effect is often called "non-stationary". This is also VERY WRONG. There are many reasons why this can happen.

For example, there are more than one measurement system in use. That is, you might take the temperatures with Fahrenheit thermometers for part of the experiment and then Celsius for the rest and not convert one set into the other. That would cause the mean to shift (because the scales have different values for freezing water) and different variance (because the definition of the Celsius scale degree is much larger). While I doubt this particular artifact occurred, there are several others that might have.

One is you are actually working with different populations, like tree rings and air temperatures, and complex composites of both (sound familiar?).

Another reason is you are changing the population of recording sites over time. For example decreasing the number of stations you are using to calculate the temperature of California to say four along the coast line. I have looked for the Video where this tidbit is explained, but I am sure others will happily post it.

Another is you f#$!ed with the data. You cherry picked the numbers you liked, and threw away the numbers you didn't like. Another is you used a computer program to systematically shift some numbers after a particular time so blatantly that when you run random data through it, the hockey stick still appeared.

Just what happened, I can't say, but if there is a Unit Root, something is wrong. It should not be there. If it is, then you have either purposefully messed with the data or you made a serious data collection mistake. Mann is renown for this.Other BH thread here

Jul 25, 2010 at 7:27 PM | Unregistered CommenterDon Pablo de la Sierra


What is red noise (in simple terms please) -
In layman's terms, a line that wiggles up and down at random.

Does it always produce a hockey stick for every run with red noise, or for only some?
In McIntyre's simulations, it produced a hockey stick nearly all of the time (99% of runs had a 20th Century mean of 1 standard deviation away from the long term mean).

Does the blade bit of the hockey stick always appear at the end of the run or can it appear in the middle of the run?
Always at the end.

Is the blade of the hockey stick the same size with the red noise as it is when the data is used?
The size of the blade varies depending on the particular dataset used for the simulation. Typically, Mann's algorithm would produce a 1.5 standard deviations blade from red noise. The PC1 from the actual data was, IIRC, slightly larger than this.

Jul 25, 2010 at 7:34 PM | Registered CommenterBishop Hill

Red noise - Variations in the dataset under investigation that do not contain a sensible or meaningful signal. However, statistical manipulations like PCA may "catch" what appears to be a signal but the signal is essentially a chance pattern - just like a coin landing heads 10 times in a row. In PCA what appears to be a factor or signal may not appear when new data is analyzed that would be expected to have the same signal in it. One technique for handling this - though I am not sure how this works with relatively small data sets of time series data is to split your data set in half and see if the same set of factors/signals are present in the two data sets. The data sets should be randomly split. Essentially if you toss the coin another 10 times and heads agains shows up 9 or 10 times, then there is something about the coin that needs close inspection. The series of 10 heads is more likely to be a signal and not a random chance event.
I hope this helps.

Jul 25, 2010 at 8:33 PM | Unregistered CommenterBernie

"What is red noise (in simple terms please) -
In layman's terms, a line that wiggles up and down at random."

Yes and no...

White noise is purely random noise. Every point is - or ought to be - completely independent of every other point.

Red noise, as I understand it, is a little different, but much more relevant. Essentially you have use a random (white noise) series to compute the _change_ from the previous value in the series.

i.e. val(x+1) = val(x) + a random amount.

The effect of this is to mimic an annual average temperature series - the temperature of the world does not change completely randomly from year to year, but is rather more "last-years-average-plus-or-minus-a-little-bit"

This is the crucial thing. If you have 1000 red noise series, some will randomly have higher periods at varying times and some may not. Feed these 1000 series into the MBH algorithm and the short-centering will mine for just those series that have a hockey stick shape and that will dominate the result.

As our host here says in the book, it really is as simple as that.

Jul 25, 2010 at 8:55 PM | Unregistered CommenterThe Pedant-General

Thank you all for your replies. There is a lot for me to think about, it's not terribly straight forward is it?


Jul 25, 2010 at 9:44 PM | Unregistered CommenterFred Windsor

Steve McIntyre has a post up at CA:

Jul 25, 2010 at 11:27 PM | Unregistered Commentermovielib


I would like to add a response to your comments but I will have to do it tomorrow as it is late here.

It would also be helpful to know if you have any technical, science, music or other background as I can try and present a response that has some connection with something you are already familiar with (I teach this stuff to geologists: if they can understand it, anyone can!) :-)

Jul 25, 2010 at 11:27 PM | Unregistered CommenterThinkingScientist

I submitted this to RealClimate. I have little doubt that it has already been rejected. AGW deserves a real debate. RealClimate, to my disappointment, seems incapable of that.


I know that you won't publish this but the amount of abuse for Dr. Curry that you are allowing to be published here is counterproductive to the cause of climate change. I have great difficult in understanding just what you think that this abuse accomplishes. Your blog and climate scientists in general already have a reputation of arrogance and being dismissive of contrary evidence. The abuse heaped on Dr. Curry here will only reinforce those views and further discredit the cause that you are trying to foster.

AGW is a very important issue that has the potential for catastrophic consequences. It deserves a more thoughtful debate than that exhibited here.

Jul 25, 2010 at 11:29 PM | Unregistered CommenterSLP

Fred I would truly be interested in the response you got from realclimate? Also if you want to read a thoroughly good book and at the same time find out more about the Hockey Stick then pls read "The Hockey Stick Illusion". There is no heavy science in there and there is a very very short laymans guide to some basic statistics that is relevant to the discussion.

Jul 25, 2010 at 11:39 PM | Unregistered CommenterDung

Fred, if it were simple, where would the fun be?

Some of it becomes simpler when you parse it into plain english. So for noise..

White noise is more random, there's no connection between data points, they're randomly higher/lower, and it's what a standard random number generator should output, with each value generated completely randomly. Pink noise is a little different. For each value, the next value is given a random offset. So it's still random, but less random than white noise.

The RC illusion is suggesting that correctly generated, random pink noise somehow contains the temperature signal. If it's random pink noise, that can't be. Random noise, pink, white or whatever is standard test data used in signal processing. The analysis that paleoclimatology people do is to try and find meaningful signals in amongst the noise contained in their samples. If your test data is random noise, then there should be no signal detected, because it's random data. Generating a hockey stick shape means something is wrong with the processing used because it's finding an artificial signal in the noise. Something is very wrong if it generates a signal/trend from random data.

The extended debate then goes into whether there is any real, statistically significant signal in proxy noise, and if there is, whether that's really a temperature signal. Gavin alludes to the challenges in finding signal in noise in his response to ThinkingScientist that TS linked on the previous page. That's interesting both for the language Gavin uses compared to his more common, robust responses.

It all sounds very scientific but basically parses down to "it's all very complicated and we don't really understand". Or, with this part-

The long-term non-stationary part is of interest - that is the part that is related to some external driver (CO2, solar, volcanoes, orbital forcing etc.). This imposes auto-correlations on the proxy signal because there that exists in the drivers.

some rather bold assumptions I think, especially when he goes on to say-

I guarantee that they are not best modelled as a red-noise process with the sample auto-correlation from real proxies.

As I understand it, red noise is better synthetic data than white noise for testing given most biological processes are closer to red than white noise, ie stuff grows or shrinks in response to some impetus that may be positive or negative. White noise would be unrealistic because biological things don't randomly shrink or grow. Red noise to me would seem better for modelling and I'm a bit puzzled by his thinking.

Jul 26, 2010 at 12:45 AM | Unregistered CommenterAtomic Hairdryer

So what of a neutral lay-person trying to compare the Montford’s Hockey Stick Illusion and Tamino’s debunking? From my accountancy experience, it is normal to try to get a sense-check. What is the expected result? If it the actual is different from the expected, then difference needs to be reconciled. The MBH98, MBH99, and the subsequent reconstructions in the book, completely overturned perceived thinking.
The sense-check for the global temperature reconstructions can be from localized reconstructions from around the world, to see if the global pattern replicates the typical pattern. A website,, documents peer-reviewed articles estimating temperatures in the medieval warm period. For those that have a temperature estimate, those that agree with the hockey stick – that temperatures were lower than today – are out-numbered 5 to 1 by those that say temperatures were higher in the MWP. The raw median, median, and mode values are that temperatures were about 0.75oC warmer than today. The weaker, qualitative, studies have a similar picture. Those that suggest that temperatures in the MWP were similar to or lower than today are outnumbered more than 4 to 1 by those that suggest temperatures were higher. So when the more scientific, global, reconstructions come up with a novel, contrary, result, there needs to a full reconciliation to explain why. Without such an explanation, we just have McIntyre’s multi-layered* findings that the global reconstructions are critically flawed stands.

*Justification of McIntyre’s findings being multi-layered at

Jul 26, 2010 at 12:52 AM | Unregistered CommenterManicBeancounter

PostPost a New Comment

Enter your information below to add a new comment.

My response is on my own website »
Author Email (optional):
Author URL (optional):
Some HTML allowed: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <code> <em> <i> <strike> <strong>