In a recent post, I challenged the Dendro Truth Squad to root out use of precipitation proxies in multiproxy studies (which the NAS Panel also encouraged avoidance of). Instead of illustrating this with bristlecones one more time (although they obviously occur in a high desert), I illustrated the challenge with the example of Dulan junipers, located in a high dry desert in China. This prompted the following anonymous response from an angry dendroclimatologist via our valued occasional correspondent, Rob Wilson, saying:
A second case in point is the broad Project for the Dendro Truth Squad’ stone you hurled up on this page. Those in the know, who really know the science, know not to use that chronology and know who still use that chronology. The work that uses that chronology for a temperature reconstruction is less-respected than others. Please, do not cast the whole field as deceitful or ignorant of this. You state that it is not your intention to slander the whole science, but why post the picture of that tree and make road statements, make a separate post about it and string a long list of papers that use that chronology if you are not trying to undermine the science? Why not post the longer string of papers that DO NOT use that one site? The final point, you and others are beating some extremely dead horses. The people and papers you audit’ is very selective. You ignore more recent work that surpasses others.
“Recent work that surpasses others”. The mouth waters at the thought. One almost expects to hear the Hallelujah Chorus playing as rose petals are strewn in the path of the work that surpasses all others. How could I have overlooked the work that “surpasses” all others? I emailed Rob to identify the work that “surpasses” all others so that I too could come and adore it.
Would it be in a humble dwelling or a royal palace? Actually I was wondering about something more mundane: did it use bristlecones or foxtails? Did it use Yamal or Polar Urals? I realize that these are pretty mundane question when you’re supposed to be adoring and the Hallelujah Chorus is playing at full volume with a 2500-member choir (the assembled IPCC scientists).
I could hardly wait for Rob’s answer. Disappointment. Rob said that he didn’t know which studies his friend had in mind and had no personal suggestions. He was merely relying comments from his friend and don’t shoot the messenger. Anyway, angry dendroclimatologists, if you know of a study that “surpasses all others”, please tell me so that I too can come and adore it.
As to the dendroclimatologist’s accusation that I’ve been “selective” in the studies that I’ve discussed, I can hardly think of a more ridiculous accusation. I’ve discussed virtually every multiproxy study at one time or another: not just MBH, but Crowley and Lowery 2000, Jones et al 1998, Briffa et al 2000, Esper et al 2002, Moberg et al 2005, Osborn and Briffa 2006, Hegerl et al 2006, plus many proxy studies including ocean sediments, alpine lake sediments, you name it. I’m trying to understand the evidence; if there’s something relevant, I’m interested. I’m particularly interested in studies that are supposed to be definitive. I’m not trying to pick on the worst studies; I’m trying to focus on the best studies. MBH was supposed to be the best so that’s what I looked at. I didn’t look at it because it was supposed to be the weakest. If there’s something interesting that I should be aware of, I’m all ears. I’d love to read the recent work that “surpasses” all others and I’ll be happy to discuss it here. So any dendroclimatologists out there – if there’s something that I’m overlooking, I’ll look at it. (And yes, twq, I tracked down Gou et al 2007, which is barely off the press and will talk about it, but it would be nice if dendroclimatologists were not always “moving on”.)
I found the following statement from the angry dendroclimatologist particularly repugnant:
Those in the know, who really know the science, know not to use that chronology and know who still use that chronology.
IPCC is obliged to use “peer reviewed” articles. So it’s not enough for “those in the know, those who really know the science” to be aware of the problems. They can’t operate like a type of masonic order with secrets reserved for the elect. If “those in the know, who really know the science” know that there is a problem with using a certain chronology as a temperature proxy, then they have a responsibility to enter that knowledge into the literature. If for some reason, they’ve attempted to do so and publication was thwarted, then they had responsibility as IPCC reviewers to enter that knowledge into the IPCC review process. As an IPCC reviewer, I exercised my right to obtain all review comments of chapter 6 of the First Order Draft and I can tell you that no dendroclimatologist made such a comment in the review process.
Secondly, I did not slander dendroclimatology by listing papers that directly or indirectly used Dulan junipers as a temperature proxy. Truth is a defence to slander and it is a matter of fact – uncontested by our correspondent – that Dulan junipers were used directly by Crowley and Lowery 2000 as a temperature proxy and indirectly via the Yang composite in the other listed papers. Yes, there are papers that don’t use Dulan junipers either directly or via the Yang composite, but the list is about the same length and these latter papers all use bristlecones and foxtails. The salient point is that IPCC uses papers that are apparently “less well-respected” without telling us which ones they are. (BTW I’m not arguing here that the presence/absence of Dulan junipers has a material impact on these reconstructions; however, the presence/absence of bristlecones/foxtails, also from high desert, obviously do have a material impact on many reconstructions, as does such trivial permutations as the use of Yamal versus Polar Urals on others.)
I have never said or suggested that the whole field is “deceitful” or “ignorant”. I’ve reported favorably on a number of dendro articles – Wilmking et al 2004, 2005; Driscoll et al; Naurzbaev et al 2004 (including Hughes); Miller et al 2006; some Russian articles. I’ve even said that D’Arrigo et al 2006 is a much better article than the more prominent Osborn and Briffa 2006 (which is heavily applied by IPCC 4AR). Martin Wilmking has written in, agreeing that my coverage of his articles was timely and fair and expressing confidence that I would report work that supported the Team as well as work that didn’t.
Words like “deceitful” and “ignorant” are words that are used in tort law. To the best of my recollection, I’ve never used either word in connection with angry dendroclimatologists and neither really expresses my views (although I would be hard-pressed to think up a complimentary adjective to describe the 1960 truncation of the Briffa et al 2001 reconstruction in IPCC TAR). People have obligations and duties beyond merely not being “dishonest” or “ignorant”. Drawing from my own experience with public disclosure in mining business, I’ve suggested that scientists have duties of “full true and plain disclosure” and of due diligence, neither of which are exhausted by merely not being “dishonest” or “ignorant.”
The IPCC said that additional proxies show “coherent behavior”. Yet we see all sorts of discordant behavior in dendroclimatology – not just between sites, but, as Wilmking and Pisaric have shown, even within individual sites. IPCC 4AR did not cite Wilmking or discuss the problem. Did dendroclimatologists acting as authors or reviewers have an obligation to identify these problems? Yes or no. If they did, why didn’t they do so? Until these and related divergence problems are sorted out, IPCC should place very specific caveats on dendroclimatological results that go well beyond any of the caveats in the Second Draft and are inconsistent with the SPM claim of “coherent behavior”. If dendroclimatologists acting as authors and reviewers don’t bring out these issues and problems, then they can hardly complain when people question how they discharged their duties in the IPCC process.
Gou et al 2006
Here’s another interesting twist to the angry dendroclimatologist’s claim that: “Those in the know, who really know the science, know not to use that chronology [the Dulan juniper chronology of Wang et al 1983]”. It turns out that the circle of the elect appears to exclude well-known dendroclimatologists Gordon Jacoby and Edward Cook.
Here is a plot of the Dulan juniper series from the smoothed version used in Crowley and Lowery 2000 (just so you get your eye in.) We do not consider here the question of whether this particular series is a plausible proxy for temperature (and, given the undoubted evidence that temperatures rose in the 20th century, as well as the nearby desert, one might at least raise an eyebrow as to whether this is a plausible temperature proxy).
Figure 1. Plot of email data from Crowley for Crowley and Lowery 2000. The citation for this series is Wang Yuxi, Liu Guangyuan, Zhang Xiangong Li Cunfa: 1983, The relationships of tree rings of Qilianshan Juniper and climatic change and glacial activity during the past 1000 years in China, Kexue Tongbao, 28(12):746-750.
Now here is the top panel of Figure 3 from Gou et al [Ann Glac 2006]. I draw your attention to the top series, which has a rather similar shape to the Crowley and Lowery 2000 series although the Crowley and Lowery has a 20th century uptick not present in the top panel – more on this later). Gou et al 2006 say that their top panel is a “tree-ring width chronology from Tianjun, Qilian Shan”, citing Yang B 2003. Adv. Earth Sci., 18(2), 285—291, an inaccessible publication. Tianjun is near Dulan (you can see it in the Shao et al PAGES location map.)
Figure 2. Caption to Gou et al 2006 Fig. 3. Temperature series and glacier advances in the northeastern TP. (a) Standardized decadal-scale proxy records reflecting surface air temperature for sites in the northeastern TP and 50 year means of regionally averaged temperature anomalies (after Yang, 2003): (1) tree-ring width chronology from Tianjun, Qilian Shan; (2) water temperature in Qinghai lake; (3) tree-ring widths from Dulan Qinghai; (4) d18O of Dunde ice core; (5) regionally averaged temperature. (b) Glacier advances (black bars) in northeastern Tibet (after Zheng and others, 1990; Wang, 1991). (c) Tree-ring width index reconstructed from the Animaqin mountains, which is negatively correlated with summer maximum temperatures. The y axis of the tree-ring width index has been reversed.
While this particular Yang B publication is inaccessible, I located two other publications by Bao Yang in 2003: Yang, B. et al [Quat Sci Rev 2003] and Yang, B. et al [Chin Sci Bull 2003]. Both of these publications included panel drawings with a Tianjun tree ring series as shown below.
This is obviously the same series as the one illustrated in the top panel of Gou et al 2006. This series also looks like the Crowley and Lowery version (other than the 20th century uptick in the latter) and, like Crowley and Lowery 2000, is attributed to Wang et al 1983.
Now there is much else to be said about the original Wang et al 1983 series, which turns out to be based only three cores from south-facing sites north of the Qaidam depression – with one of the cores being taken about 150 km away from the other two. Wang et al give locations of their cores which prove to be close to sites studied in Shao et al 2004 and described by them as spring precipitation proxies. I’ll get to that on another day.
However, going back to the original Crowley version. It is indisputably a version of the same series as the one used in Yang et al 2003 and Gou et al 2006, but it contains a 20th century uptick that is absent in the Chinese versions. What is the basis for this? Unfortunately we won’t know because Crowley “misplaced” the original version of his data. (The actual plot in Wang et al 1983 is actually a little different again than either version.)
The point today is this: if Rob Wilson’s angry dendroclimatologist friend is right and “those in the know”, those “who really know the science”, know not to use this particular series as a temperature proxy, then its use by Jacoby and Cook can only mean that Jacoby and Cook are not yet 12th-order masons. Maybe Rob’s friend should let them in on the secret handshake.