I'm continuing (occasionally) to try to collect links and resources here. What I want to end up with is one or more summary comments in which I list some intro points and links to relevant threads on several blogs. I'm thinking most of an aid for new or recent arrivals in the climate blogosphere. When I began reading some of these climate blogs just over a year ago I was faced with many thousands of threads across nearly a decade (just counting CA, WUWT, BH, and a few other interesting blogs). Andrew's books and articles offer some of the best overviews of relevant areas, of course. I'm simply trying to assemble what I wish I could have found sooner, another avenue for a new arrival to get a rough lay of the land in order to select some topics for further reading.

Jim Bouldin (Real Climate contributor but independent spirit) continues to challenge the technical basis of long term temp. reconstructions, although he emphasizes that he thinks the scientific case for concern about CO2 and temps is well established on other grounds (sensitivity, atmospheric physics, etc.). I'm not trying to get into those areas on this thread, of course, but simply mentioning that b/c Bouldin is criticizing analytical methods in dendro it doesn't mean that he's turned in his Real climate card. Still, his series is now up to 8 parts and implies that tree ring studies cannot at this time be understood as a scientific basis for millenial temp. reconstructions:

Dendroclimatologist Jim Bouldin criticizes methodological basis for long term temperature reconstructions from tree ring proxies

The three issues are:

(1) ring width, being the result of a biological growth process, almost certainly responds in a unimodal way to temperature (i.e. gradually rising, then rather abruptly falling), and therefore predicting temperature from ring width cannot, by mathematical definition, give a unique solution,
(2) the methods used to account for, and remove (“detrend”) that part of the long term trend in ring widths due to changes in tree age/size are ad-hoc curve fitting procedures that cannot reliably discriminate such trends from actual climatic trends, and
(3) the methods and metrics used in many studies to calibrate and validate the relationship between temperature and ring response during the instrumental record period, are also frequently faulty.

Each of these issues by itself would be a serious problem, but collectively they render unreliable all long-term estimates of climate change from ring widths. Worse, there are also several other issues that I don’t have time to get into, at least for now. These involve (1) the several issues dealing with which seasonal/monthly periods are the most important to the ring response, and how that determination should be made, and (2) subsequent steps in the climate reconstruction process, by which single sites are combined in various ways to give larger scale estimates. The well known, but still unresolved divergence phenomenon between multi-decadal variation in climate and ring response during the instrumental record period is potentially affected by all three of the issues discussed here, but especially the first one.

Yes, I've been following Bouldin's series.... Looking forward to the upcoming post(s) on what happened with his PNAS submission and what his manuscripts may offer to the world. I don't know where his current journey is taking him, but Bouldin seems to know a lot more about closed minds and groupthink than he might have expected to find a few years ago when he joined the RealClimate team.

I just remembered this from last summer and posted this at CA now, but I think it's also appropriate to collect here as a reminder that there seem to be odd practices with handling of data in some of these "hockey stick" proxy studies.

Compare..... last June when discussing the paucity and odd selections of long term proxy data in Gergis et al (20..?), Steve noted a very curious truncation of proxy data from Law Dome in Mann et al (2008).... (my emphasis added):

Mann and Gergis both odd in handling of Law Dome ice core proxy data

[Steve McIntyre] "...Law Dome also plays an interesting role in Mann et al 2008 – one that I hadnt appreciated before, but will re-visit. Mann et al 2008 used Law Dome O18, but did not use the long Law Dome O18 series that he had used in Mann and Jones 2003 (with its inconvenient MWP) – which would have had an impact on the sparse SH network. Instead Mann’s version of Law Dome O18 went only from 1761-1970 (!) It is a truncation of an obsolete version. I’ll discuss this backstory in another post as well...."

CA post on Law Dome and Mann et al (2008)

"Interesting" to use a truncated version of the data in 2008....

h/t Shub for this link to a David Stockwell 2006 article with a fascinating discussion of generating hockey sticks from red noise:

Reconstruction of past climate using
series with red noise, David Stockwell, March 2006

Ray Pierrehumbert in 2005 on the "educational" value of the hockey stick

23
Raymond T. Pierrehumbert says:
1 Mar 2005 at 6:32 PM

It is true that, as evidence that global warming is underway in accord with basic physics,
the hockey stick is just one item of evidence among many, and not even the most important one. However, there is a legitimate reason for putting so much energy into defending it. The “hockey stick” is an excellent educational tool. Much of the evidence and theory is complex and hard to explain. We are short on scientifically respectable arguments that can be immediately grasped by the public. I know from my own use of Mann et al when it first came out that it was a very good aid to public education about the nature of the problem. This is what it means to be an “icon.” The downside of an icon is that if it turns out to be wrong, or vulnerable, then skeptics can just try to pull down your icon and imply that everything else comes down with it. The Kilimanjaro glacier is also an icon of sorts, and Crichton’s disinformation on tropical mountain glaciers has similarly started working its way into the press.

(Note in passing: Skeptics have their icon’s too. Remember the satellite data that was supposed to show there was no warming? Why is it that there was not as much press attention paid to how wrong skeptics were about this? It’s as if they’re coated with teflon; they look bad to us, but I don’t think they look as bad as they ought to to other folks.)

Good question, Diogenes. I have seen various skeptic arguments that surface temp records can be seen to be exaggerated upward if satellite measurements differ (are lower), but not an argument of "no warming" per se. More like no worrisome warming, based upon other arguments about natural variability, etc.

I think alarmists get a lot of their mileage in arguments by sliding around between discussions of catastrophic claims vs. much more gradualist claims. They try to portray all varieties of skeptic as rejecting (in denial etc.) any claim that climate/temp. can vary AT ALL or that human activities can have any effects at all, ever, upon climate.

Speaking of "games" -- word games and more -- I want to keep a record here of how Real Climate was handling "hockey stick" debates back in 2005-07, because as I begin to review that period I find that RC functioned as a propaganda site and not as a forum for robust discussion of the science. Here are a couple of items from a thread which Paul Matthews linked at Climate Audit today:

Thanks, Paul Matthews, that is a helpful post for understanding the matter. I didn't read all of the comments but this one jumped out at me on a quick skim:

The *Real* Real Climate

Jonathan Posted Nov 18, 2008 at 2:03 PM

As a little experiment I tried posting on RealClimate (on the Mountains and Molehills thread), pointing out that I was a highly experienced and well qualified scientist who was less than entirely convinced by the AGW orthodoxy. Unsurprisingly I got somewhat flamed. So I posted a polite and fairly detailed reply, which simply disappeared into Gavin’s erratic censorship device. No explanation why, and it was far more on topic than most of the thread.

Continuing my experiment I used another account (FredB) to post a snide personal attack on myself. This was swiftly approved, despite contravening RealClimate’s stated policies. No surprise there then.

I sent in a third post pointing out this out. Deathly silence.

Any lingering doubts I had about RealClimate’s honesty have been completely dispelled.

Of course the procedure in clearly spelled out by Michael Mann in one of the Climategate emails -- block or delay critical comments in order to completely control the messaging for propaganda purposes:

Feb 9, 2006 from Mann to Osborn and Briffa cc Schmidt

> Anyway, I wanted you guys to know that you’re free to use RC in any
>> way you think would be helpful. Gavin and I are going to be careful
>> about what comments we screen through, and we’ll be very careful to
>> answer any questions that come up to any extent we can. On the other
>> hand, you might want to visit the thread and post replies yourself.
>> We can hold comments up in the queue and contact you about whether or
>> not you think they should be screened through or not, and if so, any
>> comments you’d like us to include.
>>
>> You’re also welcome to do a followup guest post, etc. think of RC as
>> a resource that is at your disposal to combat any disinformation put
>> forward by the McIntyres of the world. Just let us know. We’ll use
>> our best discretion to make sure the skeptics dont’get to use the RC
>> comments as a megaphone…
>>
>> mike

Ahhhh, since my follow up comment to Johanna over at CA has been "Zambonied" (sure I understand why, the whole discussion of influence was OT), I hope I may leave it here in case anyone stumbles upon it and wants to discuss.

http://climateaudit.org/2013/04/03/tom-curtis-writes/#comment-409756

The frustration I was trying to express has nothing to do with Steve Mc or Jean S or anyone else at CA. They are pursuing exactly the analyses they want to do and therefore should do.

When I discuss influence and the "wider world" whether in relation to climate science or to widening circles of IPCC, govt's and media, the general public etc., it is no reflection at all on CA folk (or Andrew et al) if I say that I don't see them (yet) having nearly the impacts needed. Yes, there have been influences, both scientific and non-scientific. I'm simply noting that we have a very long way to go, IMHO.

As for "seven year old emails" I'm not interested in anyone's personal pique or vendettas per se. I am simply trying to understand why I takes so long to affect the discussion among many self-styled Very Serious People both in and out of science.

====================================================

Skiphil
Posted Apr 4, 2013 at 11:35 AM |
Your comment is awaiting moderation.

Johanna,

With respect, I disagree that the “McIntyres” are doing just fine in the wider world. Yes, Steve and others have done much outstanding work, and some inroads have beem made at getting more serious attention beyond a few friendly blogs, but the overwhelming dominant effect of the Marcott study so far is from all the hyperventilating headlines and media stories, which will not be retracted or rewritten as new critical information becomes available. As for the insular RealClimate echo chamber and its “sealing” embrace of the Marcott FAQ etc., there is no reason at all to think that anything has changed in how RC and similar outlets operate. The tightly controlled insularity can be seen now, not only seven years ago.

For those who will emphasize that only the “peer reviewed” literature matters to the progress of “the science” — that is plausible on a span of decades, but in spans of months to years it is clear that there are still grave failings….. As in how studies like Marcott et al. (2013) and Shakun et l. (2012) can sail through, while it is exceedingly difficult (not impossible but far too difficult to allow robust debate) for critical and rival interpretations to see the light of day.

Speed
Posted Apr 4, 2013 at 12:32 PM |

Skiphil wrote, ” …the overwhelming dominant effect of the Marcott study so far is from all the hyperventilating headlines and media stories, which will not be retracted rewritten as new critical information becomes available.”

Perhaps Steve should be writing and distributing press releases instead of the blog.

Just kidding.

johanna
Posted Apr 4, 2013 at 12:37 PM |

I think that sinking Gergis et al is a pretty good example of how well Steve and Jean S and others are doing. The “wider world” is a term you introduced – not mine. It takes a while for things to percolate through the many filters between these arcane discussions and the rest of the world, but eventually they do. Being forced to withdraw a paper because it is rubbish is noticed in the small world of climate science, as well.

You misunderstand my point. It is not whether Real Climate or whoever are still up to whatever was revealed years ago. Quite possibly, they are.

But conflating seven year old emails with what is happening today just seems like pursuing vendettas. They are two separate issues, unless you can demonstrate a tangible link.

Adding this Amazon reader review of Mann's book, thanks to Andrew's tweet about it:

Customer Review

188 of 398 people found the following review helpful
A Tale of Two Hockey Stick War Books, March 11, 2012
By Robert Tamaki
Amazon Verified Purchase(What's this?)

http://www.amazon.com/gp/cdp/member-reviews/A1QXIKWOLUTMQH/ref=cm_pdp_rev_title_1?ie=UTF8&sort_by=MostRecentReview#R2Z9NJVEA0L1D1

This review is from: The Hockey Stick and the Climate Wars: Dispatches from the Front Lines (Kindle Edition)

For those who are familiar with the various contours of the Hockey Stick debate over the past nine years, there is only one thing that needs to be said in this review: the name 'Montford' does not appear anywhere in Mann's book - not in the main body, not in the footnotes, and not in the index.

For those who haven't a clue what I am talking about, I am referring to the book by Andrew Montford, "The Hockey Stick Illusion" (HSI). Montford's work presents the alternative perspective on the so-called Hockey Stick War, a work that came out in the wake of Climategate 1. He carefully and extensively documents all of the minutiae of the hockey stick debate, including detailed, but fully readable, explanations of the controversial scientific and statistical points, the twists and turns of the publishing and peer review processes, the outcomes of the congressional hearings, the manipulations of the IPCC process, and the discoveries of undisclosed problems with successive "hockey stick" studies. Overall, the book is a damning indictment of Mann's scientific method and his maneuvers to try to cover over his errors. For Mann to completely omit any mention of this book is a telling admission that he does not want his readers to hear "the other side" of the story.

This omission is a characteristic of the book as a whole. Rather than responding in a meaningful way to the significant and documented criticisms that have been raised by many, he fills his book with a lot of bluster, hand-waving, and accusations that his opponents are simply 'corporate/industry/fossil fuel/-funded, well-organized deniers, who have been thoroughly discredited.' Of course, he provides scant evidence to substantiate these accusations, particularly with respect to his most prominent detractor, Steve McIntyre. But the rhetorical effect is very powerful, and it no doubt persuades many (as evidenced by the number of 5 star reviews here).

One hears repeatedly that Mann's work was vindicated by the NAS study - a point that Mann relies upon in his book. However, those who have actually read the NAS study, and those who have actually read or listened to the House Energy and Commerce Committee hearings realize that Mann's methods were thoroughly repudiated by both Wegman AND the NAS panel. Under sworn testimony, Gerald North, chair of the NAS panel, was asked if he disputed the conclusions or the methodology of the Wegman's report. He responded, "No, we don't. We don't disagree with their criticism. In fact, pretty much the same thing is said in our report." Yet, Mann is somehow able to conclude that "In the end, the conventional wisdom was that Barton and gang fared poorly in the two days of hearings that summer" (Locations 3461-3462). This statement can only be supported if you assume that Mann is the sole possessor of "conventional wisdom."

There have been two primary criticisms (and dozens of secondary ones) leveled against Mann's hockey stick reconstruction: questionable statistical methods, e.g. incorrect PC analysis and poor validation statistics; and the reliability of tree rings as temperature proxies (bristlecones and foxtails in particular). However, Mann completely omits discussion of any criticisms of tree rings as a temperature proxy until he begins discussion of his 2008 paper. This in spite of the fact that he had just finished discussing the Loehle 2007 paper, which was explicitly conducted with a view to create a millennial scale temperature reconstruction without using tree rings. Nevertheless, he is constrained to begrudgingly address these criticisms because his 2008 paper was written ostensibly to demonstrate that the hockey stick is preserved without the use of tree rings. Nevertheless, amongst the many problems with this study (e.g., the use of upside-down contaminated sediment records, data infilling, truncated divergent series), the most striking was that the reconstruction only yielded a hockey stick if either bristlecones were included OR the contaminated, upside-down Tiljander sediment record was included. Take both of these out, and the hockey stick disappears! Mann 'forgets' to mention this part of the story, even though he eventually admits this in the Supplementary Information to the paper.

Mann's discussion of the Yamal tree ring record of Briffa is equally intriguing. This proxy series from the northern Russian peninsula of the same name was one of the dominant hockey stick-shaped series used in multiple temperature reconstructions. The raw data for this series had been withheld by Briffa until late in 2009, when he was forced by the journal Phil Trans B to archive his data (after 9 years). With the release of this data, McIntyre quickly realized that the sharp upward trend of the late 20th C was the result of a mere 10 cores in 1990, dropping to 5 in 1995. Moreover, amongst that paltry few, a single tree (YAD06) with an 8 sigma 20th C deviation was shown to be almost solely responsible for the Yamal hockey stick shape.

Of course, Mann neglects to share this tidbit of information in his discussion of Yamal. However, he does make a most remarkable statement, claiming that "Most climate reconstructions either didn't use the Yamal series in question anyway", for which he adds the end note: "This includes the hockey stick itself" (Kindle Locations 3944-3945). This is a starkly disingenuous comment. Both MBH98 and MBH99 pre-date the publishing of Yamal in Briffa 2000 and thus it was unavailable to the hockey stick. More than that, Yamal appears in no less than 10 of the so-called "independent" reconstructions that supposedly "confirm" the hockey stick, of which 5 are included in the IPCC AR4 Spaghetti graph (Mann's Figure 12.1). Most egregious, though, is that Mann himself uses Yamal in Mann and Jones 2003, Mann et al (EOS 2003) and Jones & Mann 2004. Hardly insignificant.

There are many more problems with Mann's work, which can't possibly be fully explored here. His discussion of Climategate deserves many pages of comment for the ways that he sidesteps the most troubling aspects of the whole affair. There are stories of imaginary spreadsheets, incorrect use of statistical terminology (i.e., "censored"), self-contradiction, allegations of criminal misconduct, manipulation of IPCC reviews, the Wahl & Ammann study and much more.

So if you are interested in the history of the hockey stick, do yourself a favor. By all means read Mann's story. But read the "Hockey Stick Illusion" as a companion book - and then you decide which account is more credible.

adding this comment which I posted on Unthreaded, since it gives some useful context to anyone finding this discussion thread:

Steve Mc makes a succinct contrast between 1998 reconstructions of Briffa and Mann, noting how different the methods and results proved to be, and also how different the reception/popularity in the paleo field proved to be. Briffa's work highlighted the "divergence" problem (until it was papered over and ignored), and 15 years on that seems not to be seriously addressed by devotees of tree rings for milennial temperature reconstructions.

I think this is a fundamental point in understanding the "hockey stick wars" -- that the people (Mann et al.) who engaged in the dodgy machinations in 1998 immediately became stars of funding, prestige, and success in the field.

The dynamics of acclaim, funding, and influence for the "welcome" messaging may provide important case studies for how science and policy can be led astray. Science should indeed prove self-correcting given enough time, but for the past 15 years paleo climate science seems stuck in a Mann-made rut.

from Climate Audit thread:

Posted Dec 2, 2013 at 3:53 PM

Robert wrote: “The alternative approach that we have seen has included downloading everything from a paleodatabase and running gridcell correlations etc… to build a reconstruction which I think of as being less convincing – even when done by statisticians.”

[Steve McIntyre]:

At the NAS panel workshop in 2006, Malcolm Hughes made an interesting comparison between two styles of reconstruction. (1) relying on multivariate methods to extract a “signal” from everything in a databank. Hughes called this the “Fritts method”, though more aptly the Mann method for most readers. Choosing small subsets from large collections is a lowbrow variation. (2) collecting data according to ex ante criteria and using simple averaging methods. Hughes called this the “Schweingruber method”.

The Schweingruber method is almost never used in current paleoclimate studies. Briffa et al 1998, 2001 were based on the Schweingruber dataset. This is the dataset with the famous decline, which Briffa failed to show in some important graphics, notably, in conjunction with Mann and Osborn, in IPCC TAR.

Mann’s reconstruction gave him fame and success, while Briffa’s occasioned zero interest and left Briffa near destitute for grant money. In my opinion, the contradiction between the Mann et al 1998 reconstruction and the Briffa et al 1998 reconstruction – both taken from large populations of tree ring sites – ought to have stimulated great interest among specialists to explain the discrepancy. Instead, in part because of Briffa’s decision to hide the decline, the divergence problem remained essentially unexplored for over a decade. Even today, the issues have mostly been papered over (through citation of the execrable article by Cook, normally a very capable scientist), rather than settled.