Recently we’ve discussed several aspects of the raging controversy around climate blogger Steve McIntyre and dendrochronologist Keith Briffa and the supposed destruction (once again) of the “hockey stick” temperature graph.
A few commentators have suggested that more attention should be paid to McIntyre’s actual “analysis” of Briffa’s Yamal tree-ring chronology, and less to his outrageous accusations (not to mention all the inconvenient evidence that those accusations were completely without foundation).
Now that Keith Briffa has delivered his promised detailed response in an article co-written with Thomas Melvin, it is a good time to do just that. Here, then, is a review of the various problems I and others have pointed out in comments here and elsewhere over the past while, along with highlights from Briffa’s response.
First, here is the abstract of Briffa’s article .
At http://www.climateaudit.org/?p=7168, Steve McIntyre reports an analysis he undertook to test the “sensitivity” of the “Regional Curve Standardised” tree-ring chronology (Briffa, 2000; Briffa at al., 2008) to the selection of measurement data intended to provide evidence of long-term changes of tree growth, and, ultimately inferred temperature variation through two millennia in the Yamal region of northern Russia. It would be a mistake to conclude that McIntyre’s sensitivity analysis provides evidence to refute our current interpretation of relatively high tree growth and summer warmth in the 20th century in this region. A reworked chronology, based on additional data, including those used in McIntyre’s analysis, is similar to our previously published chronologies. Our earlier work thus provides a defensible and reasonable indication of tree growth changes during the 20th century and in the context of long-term changes reconstructed over the last two millennia in the vicinity of the larch tree line in southern Yamal. McIntyre’s use of the data from a single, more spatially restricted site, to represent recent tree growth over the wider region, and his exclusion of the data from the other available sites, likely represents a biased reconstruction of tree growth. McIntyre’s sensitivity analysis has little implication, either for the interpretation of the Yamal chronology or for other proxy studies that make use of it.
At the same time, Briffa has also released a commentary on the use of the Yamal tree-ring chronology in multi-proxy studies and in the IPCC WG1 Fourth Assessment Report (on which Briffa was a co-ordinating chapter author).
So far, McIntyre has only addressed the latter piece and has yet to respond to the Briffa’s detailed Yamal analysis. And who can blame him? Briffa’s response effectively demonstrates once and for all the vacuity of McIntyre’s analysis and conclusions.
At this point it might be useful to display Briffa’s map showing the various Yamal locations discussed below.
Figure B
This map (after Hantemirov and Shiyatov, 2002, Figure 1) shows the area of the southern Yamal peninsula from which the tree-ring data were collected. Sub-fossil locations are shown as black dots (note that only those with rings dating to the Christian era were used in the analyses discussed here). Red dots mark the locations of the living-tree collections discussed in the text. The larch tree line is indicated by the downward pointing arrows and the spruce tree line by the upward pointing arrows.
As I see it, here are the most obvious problems with McIntyre’s analysis, most of which I have previously discussed here and elsewhere (with hat tips to dendros Jim Bouldin and Delayed Oscillator).
- There was never any cherrypicking of recent live core samples, nor could there have been. The Yamal data set of sub-fossil cores was supplemented by 17 long-lived cores collected, measured and analyzed by the Russian team of Hantemirov and Shiyatov, and the same data set was used in the Russian team’s initial chronologies and Briffa’s subsequent analyses.
- This confusion on McIntyre’s part may have also led him to misidentify the most recent 12 live-tree samples as a “selected” or “cherrypicked” subset of the live set, whereas it turned out that the other five were simply of earlier provenance and present all along.
- The 34 (or 33) Schweingruber Khadyta River data set set included 18 recent live cores, but also a number of older dead trees. The inclusion of the entire set obfuscates the point of the “sensitivity” test, which was ostensibly to “replicate” Yamal by adding or substituting a set of recent live samples.
- The Khadyta data set was collected at a specific location in the very south of the larger Yamal region sampled by Hantemirov and Shiyatov. The microsite characteristics of Schweingruber’s site are unknown (although it is worth noting that these trees are south of the spruce tree line, whereas the other live tree sites are to the north). In any event the broader regional sampling of the Russian team is swamped by the Khadyta data set, when all samples are simply processed together without proper regard for site weighting.
- Finally, Briffa repeats the obvious observation, made here and elsewhere, that the original raw tree-ring data set was not CRU’s to give out. Briffa does note that the original researchers had always granted access upon request. (It’s still not clear if McIntyre has actually ever bothered to communicate directly with Hantemirov).
Briffa’s analysis deals with all of the above issues and I won’t repeat all of the details here. However, the following points are noteworthy.
- The new analysis does include 35 recent samples from shorter lived trees, apparently published here for the first time. This larger data set lays to rest objections that the original live set was too small, or somehow biased because the trees were longer-lived.
- Briffa’s analysis correctly compares the behaviour of the recent live portion of the Khadyta set to the equivalent live samples from three other Yamal sites. (Briffa apparently did not notice McIntyre’s mistaken inclusion of the older dead tree Khadyta samples, which only serves to obscure McIntyre’s analysis).
And what are the results? Briffa convincingly shows that:
- The Khadyta River live set shows anomalous lack of growth after 1970, when compared to the other three Yamal sites.
- Nevertheless, inclusion of the Khadyta set has little effect on the overall chronology, even when the recent live core Khadyta set is added to the original Yamal data set.
This last conclusion, of course, appears diametrically opposed to McIntyre’s contentions. To understand this conflict better, let’s take a closer look at Briffa’s analysis.
Details of Briffa’s sensitivity tests are in the web article entitled “Exploring potential biases in the Yamal RCS Chronology: sensitivity to the inclusion of modern data from specific sites”. Briffa shows chronologies for four different data sets, all using the same subfossil data set, combined with various live tree sample sets. The chronologies are all standardized using RCS (regional curve standardization) on the period from 1-1600 AD, as this contains the common sub-fossil portion of the various data set variations. RCS accounts for age-related differences in tree growth, and creates a “unitless” ring-width index set to an average of 1 over the standardization period.
The four data sets include:
- Yamal AD (the original Yamal data as used in Briffa et al 2000 and other publications)
- Yamal KHAD (with 12 Yamal AD live cores excluded and 18 Schweingruber Khadyta cores included).
- Yamal AD KHAD (with all of the original Yamal AD, including the most recent live 12 series, plus the Khadyta 18).
- Yamal All (which includes Yamal AD, the Khadyta 18 and 35 additional series from the three Yamal locations shown above).
One issue, of course, is that Yamal showed strong growth in the final 1991-96 period, for which there is no data in Khadyta River data set. It’s true that there were only five trees in the original Yamal data set for the final year. However, the incorporation of additional shorter-lived trees has now expanded the data set (there are 12 more tree-ring series to 1994 from the POR site and an additional 10 up to 1996 from the YAD site).
Here is the interannual tree-ring standardized growth for the four data sets from 1950-1996.
An examination of inter-annual tree-ring growth shows only a small reduction in the final growth “spurt”, as seen in the difference between Yamal AD KHAD (magenta) and Yamal All (black). Both the original and expanded Yamal standardized chronologies attain a level greater than 3. (N.B. In this period Yamal AD and Yamal AD KHAD are identical of course; hence the superimposition of Yamal AD Khad magenta curve on top of the Yamal AD blue curve). It can also clearly be seen that, as Briffa states, “the ‘KHAD-only’ chronology is clearly anomalous in the recent period compared to the other series”.
The smoothed versions of the series show a similar story.
But even if the data is truncated at 1990, there are still puzzling differences between Briffa and McIntyre for what should be equivalent “sensitivity” tests.
Here is the 1850-2000 portion of Briffa’s “sensitivity test” chronologies, but this time truncated at 1990.
Notice that Yamal AD KHAD (magenta) rises from 1 to about 1.63 from 1900 to 1990, while Yamal KHAD (which excludes 12 Yamal AD live series) descends to about -0.80.
Now here is the corresponding chart from McIntyre.
McIntyre’s soberly-named “little bit pregnant” green curve corresponds more or less to Briffa’s Yamal AD KHAD, that is the original chronology with the addition of the Schweingruber Khadyta set. But somehow it only rises from 1 in 1900 to 1.3 in 1990, about half the rise Briffa finds. As well, the McIntyre’s Yamal KHAD curve appears to descend lower than Briffa’s, to about 0.7 instead of 0.8. Finally, McIntyre’s Yamal AD only rises to about 2.4, instead of 2.8.
These differences could be due in part to different standardization. Briffa uses the period up to 1600, in order to fix a reasonable common standardization between all data sets, but it’s not clear what McIntyre did. It’s possible that he standardized on the entire data set. But there may be other differences, due for example to McIntyre’s inclusion of the entire Schweingruber data set, instead of only the live tree portion, or different RCS implementation or smoothing.
In any event, Briffa’s analysis is far more complete and compelling and clearly demonstrates the robustness of the Yamal chronology, as well as demonstrating that the Schweingruber site is anomalous when compared to other Yamal sites.
Certainly as more data is added the “blade” portion of the Yamal regional chronology may change slightly, as for example seen in the early peek at Hantemirov’s forthcoming updated chronology using more than 200 live tree cores. But Briffa’s conclusion still stands; nothing in McIntyre’s analysis refutes “the current interpretation of relatively high tree growth and summer warmth in the 20th century in this region.”
It’s a sad commentary that, as Briffa ruefully noted, he was compelled to answer McIntyre by releasing his analysis directly to the public, bypassing the normal channels of peer-reviewed science.
Make no mistake: this is not about “doing science differently” in the internet age. There is precious little science in McIntyre’s analysis. But his barely veiled insinuations of scientific fraud have been exaggerated and trumpeted by a chorus of scientifically illiterate commentators spouting ideologically driven nonsense. Briffa’s list of such commentary, which includes The Telegraph and The Register in the U.K., barely scratches the surface. In Canada’s National Post alone, Ross McKitrick claimed that “Whatever is going on here, it is not science” and Lorne Gunter asserted that Briffa “kept reducing the number of trees from … his sample of scores of trees”.
With the U.N. Copenhagen climate conference still two months off, we can expect ever-mounting volleys of such hysterical attacks.
It’s time for scientists to ponder how to respond effectively. A good start would be a joint statement from the leading national science academies decrying both the gross distortions of climate science and the defamatory attacks on scientists emanating from the right-wing media. Enough is enough.
Deep Climate 
Nice to see the self-styled (and yet, somehow, persecuted…) arbiter of science exposed.
Still, he does serve as better and better debating short-cut; any approving reference to Steve’s statements signals that you can turn to something else.
Very nice post. And Briffa’s, poor soul, was excellent, too (hopefully now he can get back to science).
Has anyone pointed this out to Briffa or, for that matter, McIntyre?
Excellent DC! Just excellent. And Kudos to Briffa– the contrarians keep distorting, and the good science stays on track, as it has done for how long now?
Wonder if Briffa has filed a libel suite against M&M? He could and should, although his health is probably more important than wasting more time on M&M fallacious allegations. But honestly, how will they ever learn if there are no consequences for their actions?
Would it be wishful thinking for M&M to issue an apology to Briffa et al. in a press release made available to major international media outlets? I know, but one can always dream…..
Who will M&M’s next victim be I wonder? Lindzen perhaps (read sarc)?
Briffa is teaching others as well. Weren’t people saying that this Schweingruber site shouldn’t be included because it doesn’t correlate with the temperature record? Now the authors are saying that it IS reasonable to include this site.
Here is an idea. How about Briffa et al. offer to have McIntyre as a co-author? McIntyre declines, then he admits he does not trust his own work (you would think that he would jump at the opportunity to get a paper published); McIntyre agrees, then he once and for all concedes that the dendro “Hockey Stick” stands.
MikeN, which “people”? I might have stated that in my own small section of the universe, but I did not see how those who did the heavy lifting (like DO, as reported by our host) came to that conclusion. What I did read was that these data had a divergence problem and that adding the data did not affect the conclusion.
There is, of course, a much bigger lesson to be learned, and that is how an unfair criticism gets magnified, as writers rely on McIntyre and his acolytes for information.
For dragging Keith Briffa’s name through the mud, a lot of people owe him an apology, but I doubt that will happen.
Steve McI has made offers of coauthoring before.
Mike N “Steve McI has made offers of coauthoring before.”
So McIntyre has finally conceded that he agrees with the dendro Hockey Stick?
Anyhow, it is clear that McIntyre, Gunter, McKitrick, Pielke and everyone else who, in their blind zeal, blindly jumped on the ClimateAudit bandwagon to make a sincere apology to Briffa. Are they man enough to do so, or do they think that they are above admitting to errors? The irony is that McIntyre demands of people to fix their mistakes, no matter how trivial, now can he do the same for a glaring error of his own? If he does not apologise, his reputation, as that of Pielke et al. will be tarnished, not Briffa’s reputation as they had originally hoped to do. This is all going to backfire ClimateAudit.
Anyhow, now we wait for the guilty parties mentioned above to summon the courage to apologize to Briffa et al.– not just on their blogs, but in the form of a press release.
MapleLeaf, I don’t believe that McIntyre and his followers feel that they did anything wrong. This will become part of the “hockey stick is broken” saga (first Mann, then Briffa – Amman! The Team!)
Deech56 “MapleLeaf, I don’t believe that McIntyre and his followers feel that they did anything wrong.”
Don’t be fooled they likely know very well what they did/do was/is wrong, but will never admit it because it would undermine their mission. Either that or they are delusional enough to actually believe that their crusade is the right and honorable battle to win. They will not capitulate, even though McKitrick in particular should be making a public apology to Briffa. I suspect that McKitrick is not man enough, nor professional enough, to do so. Hopefully he proves me wrong.
Anyhow, ClimateAudit will likelycontinue their manic crusade of character assassination undeterred, feed the misinformation and rhetoric to the media, and even allow McKitrick to abuse his academic standing to defame scientists whose work is not consistent with their ideology. Some would argue that there is only one word that might make them behave in a responsible and reasonable manner, and that is “lawyer”.
The dendro Hockey Stick stands, not to mention the other independent proxies which do not use dendro chronologies.
Anyhow, this Briffa fiasco has shown them for what they really stand for……
PS: I wonder if Gunter is losing any sleep? A lawyer could be knocking on his door any day now at the rate he is going.
Don’t underestimate the role of bender, Raven and the other trolls, as well as McKitrick.
Eli, just who is “bender”?
Eli,
I think McKitrick is more important, at least in Canada, because he has had a platform via the National Post and the Fraser Institute. I’m planning a post on his fact-challenged and defamatory diatribe in the National Post. When I parsed it closely, it shocked even me. Stay tuned.
ML,
Bender and Raven are McIntyre acolytes who have been spotted out and about around the internet.
DC,
Thanks. But who are they really? I doubt ‘bender’ is his/her surname?
Don’t know who they are. Eli, should I?
Have you seen McIntyre’s latest post responding to the main substance of Briffa’s online material?
It’s as much an attack on Gavin Schmidt as it is about Briffa’s work. Take this for instance:
Steve:
“Briffa took some care not to associate himself with untrue allegations made by Gavin Schmidt and others. Briffa observed that “subsequent reports” had misrepresented not merely his work, but also my original posts:”
Briffa:
“Subsequent reports of McIntyre’s blog (e.g. in The Telegraph, The Register and The Spectator) amount to hysterical, even defamatory misrepresentations, not only of our work but also of the content of the original McIntyre blog, by using words such as ‘scam’, ‘scandal’, ‘lie’, and ‘fraudulent’ with respect to our work.”
Steve:
“While one understands that Briffa is more concerned about false allegations made against himself than false allegations made about me, it would have been constructive if Briffa had more explicitly disassociated himself from misrepresentations by Gavin Schmidt such as the following:”
It’s certainly a stretch, IMO, to take what Briffa said here and to think he was writing that about Gavin. As you showed anyway, Gavin’s characterisation is fair given McIntyre’s repeated insinuations and careless use of language. His later denial that he ever said or implied such things appear implausible. The published articles in the right wing newspapers appear defamatory because if they were accurate representations of CA it would show that the author of CA to be an hysterical nutjob being, as they were, full of explicit and over the top accusations. Instead, the comments made at CA by SM stop just short of being explicit accusations of deliberate malfeasance yet strongly imply it. Thus, indicating that he is just ethically challenged and no more.
I’ve seen it now.
Briffa took the high road in his responses, and was a little too charitable to McIntyre. But I’m not sure he read all the comments, and of course McIntyre’s writing style is elliptical. I agree Gavin was closer to the mark.
Briffa also pointed to Ross McKitrick’s early comment, which was a resume of all Steve’s posts on Yamal. That comment connected the dots of defamation a little more clearly than McIntyre did. But it’s all based on McIntyre’s assertions.
But I’m not sure that he’s seen McKitrick’s National Post piece (which fleshes out that early comment). It’s pretty unbelievable.
http://network.nationalpost.com/np/blogs/fullcomment/archive/2009/10/01/ross-mckitrick-defects-in-key-climate-data-are-uncovered.aspx
A couple of key falsehoods to get everyone riled up:
and
Needles to say, Schweingruber was not a co-author of the 2008 paper. He has never even collaborated with original Yamal researcher and Briffa co-author Rashid Hantemirov. But that doesn’t stop McKitrick from hurtling headlong on to the inevitable conclusion:
Shouldn’t McIntyre “explicitly disassociate [sic] himself” from McKitrick’s misrepresentations? Except that McIntyre probably agrees with them – it was all based on his insinuations and analysis. But at least he should repudiate the outright fabrications.
I just want to quote two short sentences from Briffa’s reply.
“While trees at each of the sites that we originally used show high average growth after 1970, the KHAD trees upon which McIntyre focused exhibit anomalously low growth, below the long-term mean, at this time.”
and
“Judged according to this criterion it is entirely appropriate to include the data from the KHAD site (used in McIntyre’s sensitivity test) when constructing a regional chronology for the area. However, we simply did not consider these data at the time, focussing only on the data used in the companion study by Hantemirov and Shiyatov and supplied to us by them. ”
And then leave it up to the readers to decide whether this was merely an “oversight” or whether it was indeed cherry picking.
Neither oversight nor cherry picking. As Briffa noted “we simply did not consider these data”. The simple fact is that Briffa HAD data from this region, and had no reason to go look for more data.
@Medhurst
“I just want to quote two short sentences from Briffa’s reply.”
This is cherry picking, isn’t it? You are dishonest. I have to say, you are a little “Stevo”.
Regarding Marco’s argument that “The simple fact is that Briffa HAD data from this region, and had no reason to go look for more data.”
The data Briffa used supported his hypothesis but the data he “simply did not consider” did not support his hypothesis. Coincidence? We’ll never know for sure but I believe that Briffa et al would have carefully considered all the data they had.
[DC: The “data they had” did not include Schweingruber’s Khadyta River archive. The data was available in archive, but typically co-authors consider the data they are most familiar with and not unpublished chronologies from other researchers. There is nothing suspicious whatsoever in this. And, of course, Hantemirov has been adding to his own data, with many more live cores to come in the next months.
On the other hand, McIntyre’s initial analysis removed 12 of 17 live cores from Hantemirov and substituted 34 cores from Schweingruber. The blended “little bit pregnant” reconstruction was only added a couple of days later. And even then it did not include all of the data. Now that’s how to cherrypick!]
Pingback: Kylmää vettä MOT:n niskaan « Gaia
At the beginning of three consecutive comments, Deep Climate wrote on November 2:
MapleLeaf responded:
Deep Climate replied three days later:
Back in May of 2007, Steve Bloom ID’d him as an Objectivist:
Strong ideological commitment. Those who are in it for the money tend to do brief posts and basically argue as if their heart really isn’t in it. Heck, they may even be inclined towards kidding around some. But bender isn’t like this. He was tenacious — and that kind of tenacity (and general nastiness, I might add) typically involves ideological commitment. And the only people he wanted to debate were the climatologists themselves. So yes, as Eli says, he is a troll — one motivated by ideology. Same sort of thing we saw in Steven Mosher when he first showed up — although hardly to the same degree.
[DC: I want to clarify that I am not interested in bender’s identity, nor that of any commenter for that matter. The only possible exception would be if there were strong evidence that an anonymous commenter was a paid troll. I see no evidence of that at ClimateAudit from the brief time I spent there.
I tend to agree that almost all opposition to climate science seems driven by ideological bias, especially when that opposition comes from those motivated only by their convictions. However, I don’t share what I take to be Eli’s evaluation of the relative importance of such commenters in the public discourse, but it’s possible I’m missing something.
Finally, I’ve taken the liberty of correcting Steven Mosher’s name.]
Re DeepClimate [my post above.]
Over at Desmogblog I get the distinct impression that there are some individuals who are actually getting paid, but at most places they do seem to be the exception. As for remembering peoples’ names, once I was making out a check, and when came time for my signature I drew a blank…
Ah, Steve is at it again, see here where he takes an interesting article about the changes at the ecotone between L. Sibirica and tundra and tries to use it to indict Briffa’s work. A few problems with this:
1) The transitions which are noted as remarkable seem to be taking place in uplands, rather than river bottoms.
2) The transitions seem to be taking place in fairly young individuals. The HS live samples are all older trees.
3) This paper confirms a large increase in temps in the region in the 20th C (.9 C). It also shows a large increase in precipitation. Growth is correlated with both of these factors.
It would seem to me that this paper confirms Briffa (2000, 2008), so I am puzzled why the feces flinging monkeys (feel free to substitute a different description if you can think of one) over at CA are so happy to find this.
The other article is here. In this piece Steve seems to be arguing that HS collected and Briffa used inhomogeneous samples. Briffa defines inhomogeneity as using samples which would be expected to respond differently under the same external forcing. Think different species or very different habitats. Here the species were all Larix Sibirica and they were apparently (see map above) collected in river bottoms withing 50 km. of each other.
I’m having trouble what Steve thinks he is on to and why he thinks that Briffa doesn’t understand how the method that he, Briffa, developed. I guess Steve is just desperate for more attention.
I think you should read the Devi et al paper a little more closely. Then relate it to the discussion thread.
Regarding your point #3, there is considerable increase in precip during the 20th century. If trw is strongly correlated with precipatation *and* temperature then how should a chronology be interpreted? RCS cannot distinguish the cause of the environmental signal.
In single stem forms, ring width is correlated most strongly with previous year summer temps, with precip playing a smaller role. Winter precip plays a bigger role in creeping and upright multi-stem forms.
Most of the stems from upright multi-stem forms are fairly young, not the 200-400 year old cores in the live samples from HS.
RN, read more closely. After vertical growth starts to appear in the early 1900’s, TRW increases in the older *HORIZONTAL* stems of the multi stem clusters. Figure 8 shows this effect quite clearly.
–
Here is the relevant quote:
“The change from creeping to vertical
growth led to significant growth enhancements of the
multi-stemmed trees, as indicated by the increases in
the ring widths of the horizontal stems of multistemmed
trees (Fig. 8). Approximately one to two
decades after the stems had started to grow vertically,
ring widths increased 2- to 10-fold, which were much
greater than the increases in ring width of singlestemmed
trees during the same period.”
I’ll guess I’ll go back to “flinging feces” now.
Yep, but since chronologies are typically bored at chest height, why would that affect the samples bored by HS?
Still flinging feces.
So chest height sampling is typical in dendro TR sampling is it?
First off, even if you were right (you’re not), do you really think (snicker…) that HS would have excluded an old horizontal stem because they don’t deviate from a vertical scale for a (more or less) horizontal tree? They somehow can’t figure this out or something?
From: “A Manual and Tutorial for the Proper Use of an Increment Borer”; Grissino-Mayer, Tree Ring Research, Vol 59 (2), 2003
“Because most dendrochronological studies require the maximum ages for living trees be attained, coring at breast height (ca. 1.3-1.4 m) is rarely justified. Obtaining cores at breast height is useful only when coring trees (such as pines growing in plantations) to help standardize calculations of the potential yield of wood for a given stand. Many dendrochronologists extract cores as close to ground level as possible while still allowing room for the handle on the borer to turn.
From my reading of the article, the multi-stemmed trees discussed are mainly up the slopes near the altitudinal tree line. The valley bottoms feature a very high proportion of single stem forms.
My understanding is that Hantemirov and Shiyatov sampled along the rivers (i.e. at the bottom of river valleys). I’m not aware of evidence that their samples included multi-stem forms.
Layman, this is from Wiki:
Effective use of an increment borer requires specialized training. Samples are taken at breast height or stump height of the tree depending on the user’s objectives.
And I would urge you to look at the photos in the source you cited. What height are the cores being taken at? Breast height. So while what you state may be true for some circumstances, it is not always true. My understanding for dendroclimatological as opposed to strictly chronological studies it is customary to core at breast height.
It is also interesting to note that the Graybill cores which Steve makes such a fuss about all seem to have been drilled considerably above the base of the tree. In fact the only picture of actual drilling I found in Steve’s little photo show had a core being taken at what? That’s right, breast height. Obviously, practices differ. Please provide evidence that HS did something other than sample at breast height from upright stems from trees in bottomlands. If you cannot do this (hint, write to the author with your question, don’t accuse him of incompetence and/or fraud in your communication) please provide some rationale that when, presumably, looking for trees fairly typical in growth form, they would disproportionately sample tree growth forms which make up less than about 1/3 of the population.
And DC is right on. The paper repeatedly talks about looking at these phenomenon within 50 m (vertical) of the species line. If you look at the map, you will see that HS sampled along river bottoms and not in uplands.
Trust me RN, if H&S had no apriori reason to exclude horizontal stems they would have been sampled, chest height or not. If you can find a citation which confirms there was nothing under chest height for HS then go ahead an have a go at it.
Not sure where you are getting that from DC. Could you point me to where you read that?
Figure 4 shows the tree distributions at various altitudes in the 3 transects and the majority of the multistems were at the lowest elevations sampled. On the east slope transect, single stems are dominant at all altitudes. In the other two transects, the distribution is more even. As you move up slope in the SE and NE transects, there are proportionaly more multistems (still less overall than lower elevations).
Figure 6 shows the ages of the single and multistems. Note that for the older trees, the proportion of single vs multistem is allmost even with one transect mixed and single stem dominant in east slope and multistem dominant in SE slope.
DC, it is a fair point that there is no evidence that their samples included multistem forms. But there is no published metadata which would categorically rule it out either. I think it is a fair question to ask.
Yes, in general, the proportion of single stem is higher at the lower elevations. Overall, among the stands surveyed more than 80% of the trees are single stem according to the authors. The percentage is presumably even a bit higher in the lower “closed” and “open” forests.
I do see the Northeast slope has 38% multi-stems in the closed forest. But that’s at 220 m.
In the denser Southeast slope, the multi-stems go smoothly from 13% at 197m closed forest to 57% at the 265m “tundra-species” line.
Also, the Yamal sites are somewhat to the north east of this study’s location. I have no idea of the topography in the area, or percentage of multi stems along the river terraces.
I’d say these are questions best asked of Hantemirov, but I’d be surprised if he would have sampled trees with such an obvious confounding factor.
As you know, I personally don’t go as far in harsh language as some. But I do find there’s a lot of unfounded speculation in the whole discussion of the multi stem larches.
If I turn out to be wrong in that, so be it.
These are fair points DC. I don’t intend to discuss the multistem trees of Devi et al as some kind of smoking gun which falsifies Yamal. It is, and remains, an interesting question.
So far I have not seen any reason why this matter should not be explored. If it turns out to be a non-issue then “so be it”. 😉
Layman,
The most recent recruits were all single stem forms and therefore closer to the species line. Earlier recruits were multi stem or creeping. Bottomlands contained mostly single stem forms.
“Bottomlands contained mostly single stem forms.”
As I mentioned to DC, this statement does not hold true if younger trees are excluded. The ratio for older trees is almost even. A large majority of multistems were found at the lowest elevations. The dominance of single stems in the eastern transect does not appear to be related to elevation as single stems were dominant at all altitudes.
I think you misunderstand. The youngest single stem trees are found or near the species line. Single stem dominate in the closed forest.
If I am misunderstanding something, I would appreciate it if you could cite the relevant quote or figure.
Layman Lurker quotes:
Fair enough.
*
Later Layman Lurker states:
So let me get this straight. You are going on the hypothesis that the experts didn’t know any better than to avoid the multi-stemmed trees — even though they were dendrologists — scientists who specialize in the interpretation of tree-rings and the conditions of tree growth? Are you entertaining this merely as some sort of logical possibility?
Would you argue that it is possible that they committed murders — given the fact that we can’t categorically rule out that possibility?
*
Lay Lurker stated:
So you bear no responsibility for providing evidence that authors sampled the trees without any regard on their part for such variability, but it is incumbant upon Deep Climate to demonstrate that they didn’t make so elementary an error? Will you be expecting him to demonstrate that there are no leprechauns too?
*
Lay Lurker stated:
Well you could certainly explore it. Perhaps even bring back evidence of such gross negligence on their part if you should happen to find it. Better yet you could do one of your own studies, control the variables, rely upon recognized principles to objectively demonstrate that certain proxies suggest a different temperature record. Then get your study published in a peer-reviewed journal. That is how science is generally done. Then if your record differs from theirs this may provide justification for further, more detailed and exacting studies.
And if I may now return to the previous statement yours, “It is, and remains, an interesting question.”
What is it that makes it an interesting question? The fact that you can arbitrarily suggest that specialists didn’t commit some elementary error since they didn’t specifically state that they avoided it? The fact that this permits you to throw “mud” on a study that you find politically inconvenient? That you can arbitrarily focus on this one piece of evidence and suggest ad hoc reasons for arbitrarily dismissing it or its justificatory weight? That you can do so while ignoring extensive body of studies that similiarly demonstrate the warming of the past century and how unusual it has been in relation to the paleontological record?
Here is a short list of a few such studies:
Robert N. Harris and David S. Chapman (1997) Borehole Temperatures and a Baseline for 20th-Century Global Warming Estimates, Science, Vol. 275, pp. 1618-1621
ftp://ftp.gfz-potsdam.de/pub/home/se/nina/Material-zur-Geothermie/Literatur/harris-science-1997.pdf
Rowan T. Sutton, Buwen Dong, and Jonathan M. Gregory (2006) Land/sea warming ratio in response to climate change: IPCC AR4 model results and comparison with observations, Geophysical Research Letters, Vol. 34, L02701, pp. 1-5
Click to access Sutton_etal_GRL2007.pdf
S. Levitus, J. Antonov, and T. Boyer(2005) Warming of the world ocean, 1955–2003
Geophysical Research Letters, Vol. 32, L02604
Click to access Levitus_etal_GRL2005.pdf
Brian J. Soden et al. (4 Nov 2005) The Radiative Signature of Upper Tropospheric Moistening, Science, Vol 310, pp. 841-843
Click to access Soden.pdf
Gian-Reto Walther et al (28 Mar 2002) Ecological responses to recent climate change, Nature, Vol 416, pp 389-395
Click to access Walther%20et%20al%20Nature%202002.pdf
Eric Rignot et al (FEBRUARY2008) Recent Antarctic ice mass loss from radar interferometry and regional climate modelling, Nature Geoscience Vol 1, pp. 106-110
Click to access 2008_Rignot_NatGeo.pdf
Michael Zemp et al. (2009) Six decades of glacier mass-balance observations: a review of the worldwide monitoring network, Annals of Glaciology 50, pp 101-111
Click to access a50a018.pdf
Hamish D. Pritchard et al (15 Oct 2009) Extensive dynamic thinning on the margins of the Greenland and Antarctic ice sheets, Nature;461(7266),971-5
Click to access extensive-dynamic-thinning-on-the-margins-of-the-greenland-and-antarctic-ice-sheets.pdf
A. Cazenave (18 October 2008) Sea level budget over 2003–2008: A reevaluation from GRACE space gravimetry, satellite altimetry and Argo, Volume 65, Issues 1-2, Pages 83-88
Click to access SeaLevelRise2008.pdf
You can play Descartes all you want, staring in disbelief at your own hand since you can’t actually prove beyond all doubt that it exists. You can invent all sorts of scenarios in which the presence of your hand would be illusory. Hallucinations, demons, brains in a vat, aliens and so on. You might choose to think such an exercise interesting. However, in the world of empirical science at least, when multiple independent lines of evidence transmit justification to the same conclusion, the conclusion generally receives far greater justification than it would from any one line of evidence in isolation from the rest — and arbitrary cartesian scenarios count for next to nothing.
Timothy, you may well be right – this might be a well known and elementary issue for dendros. Maybe the “multistem” effect in larches is well documented in the literature and no dendro would ever sample a multistem. I am not a dendro and I don’t know. But if it was *not* well known or documented in literature, I would expect that H&S would have sampled the multistems (if present) because not to do so would have been selective, and that is a no no. Unlikely deviations in the collected data could then be tracked back to multistems through the metadata and identified as an inhomogeneity. IMO, such an excercise should have been included in a publication so that it could be properly reviewed.
The way I read the Devi et al paper, multistem larch would have made up a significant portion of the old trees at all altitudes in 2 of the 3 transects sampled. RN reads it differently. If he can support this by pointing out the parts of the paper that I have missed I am totally open to that.
The reason I find this “interesting” is that if my understanding is correct, then it seems at least plausible that multistems could be represented in a similar way in H&S sampled area – roughly 200k away.
Layman, I suggest that you look at table 1 and look at the altitude of the various stand types. Then look at table 2 and look at the stand composition.
It is interesting to note, however, that at species line, especially on the east facing transect, that single stem forms predominate. This is counter to my experience tagging along with plant biologists looking at treeline structures in the Sierras of California where multistem forms (Krumholtz) tend to predominate at the species line. Clearly something odd is happening at the species line.
But we are not discussing what is happening at the species line. At the lower elevations, in the closed forest, single stem forms dominate as would be expected given the advantages that upright trees would enjoy.
Yes single stem forms dominate at lower elevations, but we must narrow it down further to older trees. Figure 6 shows us that a majority of of the single stem trees in the closed forest are also young (less than 100 years). IOW the proportion of old trees which are multistem in the closed forest is significant.
Layman, Figure 6 doesn’t break out structure by stand type, it shows the breakdowns by transect slope orientation.
Multi stem trees are cross hatched, single stems are red. So looking at the data transect by transect, you see the SE slope is almost all young trees (therefore for the closed forest single stem type is almost all young trees). The NE slope a few old trees which are single stem, but it is obvious that this cannot account for the majority of the stand density at lower elevations. The east transect is virtually all single stem regardless of elevation or age. However, the majority of old single stems are in this transect.
LL,
Consider this key passage:
The point is Devi et al a site in a different region (Polar Urals) and different topography (slopes rather than river terraces). The area discussed is one where the majority of trees are young and the site reflects the effect of 20th century warmth close to the upward moving altitudinal tree line.
The data does show that in general the proportion (and age) of single stem trees decreases with altitude.
But more importantly, there is no evidence whatsoever that this site has any application to Hantemirov’s Yamal sites. For one thing, there is evidence that this site is partly precipitation limited. Hanemirov’s river terrace sites are chosen to be temperature limited as much as possible. For another, Hantemirov was primarily interested in old trees, so he would not have chosen sites with so much new growth.
I’ll say it again – the discussion of Devi et al at CA is unfounded speculation. Nothing more.
If McIntyre or anyone else thinks otherwise, they should communicate any questions they have to the researcher (Hantemirov in this case).
I think you’ve had plenty of chance to express a dissenting view. But the discussion is becoming very repetitive.
DC, thanks for being patient and letting me post on this. I agree there is not much more to add.
Layman Lurker wrote:
The fact that you were able to find it in the literature strongly suggests that it is well known. And dendrochronologists might reach for multi-stems — while controlling for this effect — if they were interested in precipitation rather than temperature — where temperature is best indicated by the tree ring growth of single stems.
Furthermore, you are using a point that has been established by experts in dendochronology in order to arbitrarily undercut the conclusions of experts in dendochronology in some other area — as a layman and without evidence. But one could just as arbitrarily suggest that the difference that dendochronologists have observed between multistem and single stem was some sort of artifact due to their failure to control for someone slipping in at night and giving the multistems plant food.
*
Layman Lurker wrote:
One is being selective when one selects larches over other conifers, e.g., spruce (piea obovata) or birch (betula tortuosa) which are also found in the area. And one needs to be selective when controlling for variables — as closely as possible, holding all but one constant — so that the remaining variable may be used as a proxy for some other variable, in this case, tree ring width for temperature rather than precipitation. We know that multistem growth is much more dependent upon precipitation whereas single-stem growth is much more a function of temperature. Good reason for selecting the single-stem over the multi-stem, wouldn’t you think?
Would you consider controlling for variables a “no no”? Trees were selected from the river bottoms as tree growth along slopes would be much more dependent upon the angle of the slopes, both relative to horizontal and relative to the angle of the sun — or for that matter, prevailing patterns of atmospheric circulation. If you believe that controlling for other variables is a “no no,” then it would appear that Briffa doesn’t agree with you. Then again, it would appear that you don’t agree with yourself — insofar as your entire argument revolves around the need to control for multi-stem vs. single stem.
*
There is a game that is often played by those who do not like where the evidence leads. They will focus upon one line of investigation only — that which they regard as most vulnerable. In paleoclimatology, at least in recent years, it has often been dendochronological investigation — because dendochronological evidence has been weaker than other forms of evidence for the paleoclimate temperature record. Thus for example they will continue to focus on the dendochronological even in the face of Mann’s most recent work that shows a robust hockey stick independently of dendochronological evidence altogether.
More recently Briffa has been at work showing how it is possible to define a fairly rigorous methodology that strengthens the sort of justification one is able to obtain from dendochrological evidence. This is unpopular among those who prefer playing games over peer reviewed science. Real Climate has pointed out that there are plenty of hockey sticks that in no way depend upon dendochronological evidence here that are all saying more or less the same thing with regard to the temperature record. I have pointed to a variety of papers representing a rather varied set of lines of investigation above between which there is a similar agreement. And I have also pointed out that a conclusion supported by multiple, independent lines of investigation generally receives far more justification than it would from any one line of investigation in isolation from the rest.
*
You have a game of sorts going, one in which you do not actually have to prove any allegations or even supply evidence for their basis, but merely introduce “reasons” for doubt based on mere logical possibilities. Then according to the rules of this game as they have been tacitly layed down, it is up to those you are playing against to prove those allegations are wrong — and to supply the relevant evidence as part of those proofs. As long as they choose to play by these rules and argue with you over the fine details of dendochronology, this artificially elevates its apparent relevance in establishing the temperature record and creates the appearance of a genuine controversy with regard to that record. No wonder you find this an “interesting” game.
I choose not to play. Rattus Norvegicus has apparently chosen to play a little while longer — and is at least making some points that are genuinely interesting. That is his perogative. Regardless, I think it worthwhile to identify the nature of the game and the actual stakes that it is being played for, and that is mine.
“There is a game that is often played by those who do not like where the evidence leads. They will focus upon one line of investigation only — that which they regard as most vulnerable.”
“You have a game of sorts going, one in which you do not actually have to prove any allegations or even supply evidence for their basis, but merely introduce “reasons” for doubt based on mere logical possibilities.”
“You have a game of sorts going, one in which you do not actually have to prove any allegations or even supply evidence for their basis, but merely introduce “reasons” for doubt based on mere logical possibilities. Then according to the rules of this game as they have been tacitly layed down, it is up to those you are playing against to prove those allegations are wrong — and to supply the relevant evidence as part of those proofs. As long as they choose to play by these rules and argue with you over the fine details of dendochronology, this artificially elevates its apparent relevance in establishing the temperature record and creates the appearance of a genuine controversy with regard to that record. No wonder you find this an “interesting” game.”
Got to hand it to you Timothy, you’ve seen through my scam right from the start. I guess I am going to have to retreat and hone my skills a little more if I’m to have any hope of pulling this off. 😉
Timothy,
I agree with every point you have made. Layman Lurker (any by extension, McIntyre) is engaging in what is known in evolutionary circles as the Gish Gallop. By citing a graph which does not show what he claims it shows and then making additional claims which are not supported by the paper he shows that he is doing the Gish Gallop.
My guess is that (since this is not reported explicitly in the paper) that most of the studied transects fall between the upper edge of the closed forest (established for >100 years) and the species line, since this is the primary area of interest. After all, they seemed to be looking and collecting data on changes in growth forms in an area where the treeline was expanding and not at the structure of established forests. If you look at the map of where the HS samples were taken. Your point about being the Devi et al site being precipitation limited is a good one. Trees in riverine valleys, where the HS samples were taken would, because of the higher water table, not be presumed to be limited by the availability of water. But then these are the sorts of considerations which go into site selection when doing dendroclimatological studies.
However, the next stride in the Gish Gallop is already taking shape with McIntyre’s “homogeneity” analysis. There is one glaring error in Steve’s analysis: by looking athe the growth curve of only living samples he introduces what Briffa refers to as “modern sample bias”. He further confounds this error by only considering cores from the two slower growing sites (KHAD and JAH) vs., apparently, the entire subfossil sample set and YAD and POR vs. once again, the entire subfossil data set. The problem with this approach is that he is comparing trees which grew during a different forcing regimen (the living samples) with the entire subfossil series whose trees grew in a variety of forcing regimens, thereby missing the point of RCS standardization entirely. This is not what Esper, et. al. did in the paper he cites as authority at all.
In addition, Steve asserts that this is a statistical question, something which I beg to disagree with. This is a biological question and since the sites are similar and the species are identical for both modern and subfossil samples the a priori assumption is that growth regime would be similar. Steve has done nothing except show that modern sample bias is real.
RN,
I made a similar comment on homegeneity analysis over at Delayed Oscillator:
DO’s reply
DO’s post goes into detail on why comparison of RCS curves at different times is inappropriate. Worth a look for anyone interested in these issues.
DC,
Au contraie, mon frere. Jeff wants to show that if you remove the modern climate signal you don’t get a hockey stick. Which of course is what happens. The only problem is that the analysis is invalid, completely missing the point of what RCS is trying to do.
Of course you will never be able to get someone who is bent on misunderstanding dendroclimatological techniques to understand this.
RN,
The two analyses are similar, with McIntyre throwing in the specious comparison to Esper’s homogeneity analysis.
I think we’re making the same point: RCS is designed to preserve the climatic signal. CA and acolytes are misusing it in ways that remove the climate signal. All of the analyses that treat the 12 live-core separately have this problem.
Delayed Oscillator put it very well in his Yamal IV post:
Rattus Norvegicus,
I have dealt with creationists some myself — and have a decided interest in evolutionary biology. I was a member of DebunkCreation for perhaps two years and helped found the British Centre for Science Education. But what most interests me are retroelements and their origin and role in evolution. From the RNA World to the hypermutative tandem repeats left in coding, intronic and regulatory regions as the result of template switching by LINEs and and SINEs, to the origin of LINEs and spliceosomal introns in infectious elements known as mobile type II introns, to origin of LTR-retrotransposons in the fusion of a LINE with a DNA transposon and retroviruses in the acquisition of an ENV-gene by a LTR-retrotransposon, to the role played by endogenous retroviruses in the creation of a barrier to the mother’s immune system in placentas.
*
What you said regarding the riverbed’s high water tables got me to thinking. Earlier you had stated:
Layman Lurker replied:
… and of course no evidence was offered at that point.
*
If you go back to look at his response to Deep Climate here, he states:
But what are the “trisects”?
Deep Climate had stated:
Deep Climate refers to “slopes.”
Looking at Devi et al 2009 figure 4, they aren’t speaking of trees but of biomass, and in that figure they make no reference to younger trees. Furthermore, you see that they are likewise referring to “slopes”: the SE, NE and E — just as Deep Climate had. So we aren’t speaking of riverbed at this point but of the region between the the crest and the valley. And while it is true that more multi-stem mass is found in closed forest as opposed to say tundra where there is very little biomass for either single stem or multi-stem, the closer one gets to closed forest, the more tilted things become in favor of single-stem.
Responding to Layman Lurker, Deep Climate states in greater detail than what I had arrived at on my own:
To this, the full extent of Layman Lurker’s response is:
As such, not only has he misrepresented to you his response to Deep Climate on a variety of points, but he had more or less raised a white flag on the particular set of issues he was debating with Deep Climate at that point. Frankly I hadn’t seen much of any of this until I had looked over it rather closely this morning — after writing nearly all but the first paragraph and very last sentence of what follows below — in response to your statement that, “Bottomlands contained mostly single stem forms.”
*
If the same effect that Deep Climate identified holds of a population shift from multi-stem to single stem in moving from tundra to closed forest applies the closer one gets to riverbed, then by the time one actually reaches the riverbed single-stem should clearly dominate — just as you had stated.
But why? In place where the water table is high one would expect the canopy and brush to be high as well. Reaching the sunlight will be at a premium. A plant’s best chance at survival will be achieved by growing tall as quickly as possible. Any extraneous investment — such as with multistem growth — will be wasteful and will in all likelihood result in a high mortality rate at each stage in development. And of course as the plants grow they will be encroaching upon one another, so there will be competitors for sunlight at each stage in a plant’s development.
Thus if anything, the ratio of single-stem to multi-stem should be more tilted towards the single-stem the further one progresses in the stages of development, not less. And trees generally have a very high rate of mortality going from sampling to mature brush, so single-stem would no doubt be strongly selected for under such conditions. Thus it would be the near absence of adult multi-stem larches in the area which would explain the rarity of the multi-stem saplings. What multi-stem saplings might be there would in all likelihood be from a parent tree found much higher up, with the pine cone falling down and per chance being carried there by a flood or by the stream itself. They would be entirely weeded out within a few generations were it not for an occasional transplant.
In any case, I should try to keep it short today — I have a fair amount of catchup to do after a case of the flu.
Rattus Norvegicus wrote:
I believe I can see what you mean. The forcing is of course what results in climate change — along with the climate feedbacks. And in essence a tree carries within it its history, a history that includes the earlier climate regimes that it saw as it was maturing.
It will have responded to the precipitation and temperatures that it saw by developing in a particular way. It will be just as if you a child were born at a higher altitude that child would be subject to greater arteriogenesis in response to the lower partial pressure of oxygen.
These internal resources that the organism develops as the result of its earlier history are what it has with which to respond to its environment at a later time. Thus for example, if one takes the child that grew up at a higher altitude to a lower one the child will have greater stamina for long-distance running than it would if it had been growing up at that lower altitude all along.
*
Rattus Norvegicus wrote:
The resources and other marks of its history… so it would seem.
Rattus Norvegicus wrote:
So the “a priori assumption” would be the null hypothesis, and by identifying the evidence against the null hypothesis, in essence Steve has provided support for the very thesis he was arguing against. Some would call that “poetic justice.” In any case, I like it.
Timothy,
Yes, I believe that Steve has just identified the climatic signal. Of course the other mistake he is making is that he has reduced the sample size to such an extent that it is not possible to get a valid RCS curve. Steve’s analysis has so many errors and ignores so much of the published research on developing RCS curves that anyone taking it seriously is credulous in the exteme.
In a somewhat related development, RC has published a post describing a new bristlecone pine dendrochronology study published in PNAS. I haven’t checked, but we should be ready for the all-important blog review of this paper by the Team shortly. Wonder if my recent adversary (see link) will pick up on this.
I think McIntyre is on it already.
By the way, for some reason your comments have to be fished out of the spam folder. Not sure why, but it could be the URL you use.
Thanks, DC. The local commentary can be pretty spam-like. I will leave the website blank this time.
From what I read, Salzer’s study makes it much more difficult to reflexively toss out the BCP data – and bolsters the reconstructions of Mann, 2008. They point out that the temperature dependence may be iffy for the younger wood from over 2K years ago. But the blog review has started.
DC, RN, you will be interested in the following book – “Methods of Dendrochronology, Applications in the Envrionmental Sciences”. Specifically to chapter 2, section 1, written by Schweingruber, Kairiukstis, and Shiyatov on tree sample selection. It is a google books link, so not all book pages are included.
http://books.google.ca/books?id=zr8Ucld6FYcC&pg=PP13&lpg=PP13&dq=Schweingruber,+F.H.,+L.+Kairiukstis+and+L.+Shiyatov+(1990).+Sample+Selection.+Methods+of&source=bl&ots=ZgEm0rIQKG&sig=4qSNXkL9FJvFgx8NiuNgz8s2N2k&hl=en&ei=mu4ES8HNJ8a_ngep6f3ACw&sa=X&oi=book_result&ct=result&resnum=6&ved=0CB4Q6AEwBQ#v=onepage&q=Schweingruber%2C%20F.H.%2C%20L.%20Kairiukstis%20and%20L.%20Shiyatov%20(1990).%20Sample%20Selection.%20Methods%20of&f=false
The following passage (page 27/28) speaks to sampling height: “To obtain the longest possible ring sequences with a minimum of individual variability, samples are taken at breast height.”
It appears that RN was correct on this point.
There is also discussion of apriori stand, site, and tree selection criteria for live trees which you will also find interesting – particularly references to age, sample size, and closed vs. open stands in order to isolate the climate signal.
No mention specifically of excluding multi stem trees. In the absence of any references to the contrary, I do not believe such trees would be excluded merely on the breast height criteria as the need to satisfy sample randomness would be paramount. It would seem more logical instead to choose a point sufficiently removed from the base which would minimize the individual variability.
Reasons for apriori selectivity must have a scientific foundation. In an example at CA, Rob Wilson spoke of excluding scarred trees from sampling based on the considerable research which documents the bias.
As I have qualified before, I am not suggesting that such a foundation does not exist, nor am I suggesting that multi stems must have been represensted at the H&S sites.
Then we can only conclude that you’re suggesting that your own knowledge of the subject is pitiful, though growing slowly as you read and learn.
Why not spare us your polemics altogether since you’re now saying, in essence, “I have nothing useful to say regarding Briffa et al”?
This is absolutely unbelivable that the most critical political and economical decisions mankind ever made planning its future are base on completely unclear, metodology dependent, and bias-sensitive assumptions about climate change.
In my humble opinion – if facts are that one bloody tree-ring may matter billion Euro expenses from the public money in the name of “climate protection” – I entirely refuse the whole concept and would rather spend this money on something much better validated.
[Unsupported, vague and manifestly false accusations removed per comment policy.]
Ziggi, yeas creating dendro chronologies is a tricky and difficult science. That is why we, fortunately, have numerous other methods for generating temperature reconstructions (ice cores, lake and ocean sediments, corals, bore holes etc.). Funny then, how how these independent proxies agree remarkably well with each other.
And the theory behind the radiative forcing of GHGs goes way back to Fourier’s seminal work in the early 19th century. Not to mention the fact that GHG forcing has nothing whatsoever to do with the reliability (or not) of dendro chronologies.
But I see that those in denial have done a fine job convincing you otherwise.
On the other hand – you must agree that each method of climate study gives results what are prone to serious variations on slightest change of the input data and, each of these study gives us different assumption of the trend (results vary from temperature rise of 0.005 Celsius per ten years to up to 0.6 Celsius per decade. This is rediculous and of course – this is more a political bias what results and what methodology you want to consider more relevant.
On to of that – this is the most important – while scientific data are of this nature – nobody should come to public like Al Gore – with simple and “no doubt” message as if he ate all wisdom.
We are talkin about massive cost for all of us and in case there is so much scientific hesitation I can’t treat it otherwise as an attempt to rob my pocket under the flag of pointless “global warming fight”.
Simply – I do not agree to pay a penny if such information is valid:
Click to access fulltext.pdf
And as dispute with this message is more than sophisticated debate on the edge of any meaning – I would rather trust in God than pay my money to greedy politicians and zealous eco-activists.
Ziggi,
You cite one study for one site chronology (Tornetrask in Fennoscandia).
Grudd was also co-author of Briffa et al 2008, which includes three broader regional chronologies, including Fennoscandia and Yamal.
http://rstb.royalsocietypublishing.org/content/363/1501/2269.full
Broadly speaking, that study showed increased 20th century warmth (relative to MWP), as one moves further east across Eurasia.
You have to look at the overall picture, not just one particular site or region.
[DC: Ziggi, you are repeating yourself. That’s enough now.]
Hmm,
As you wrote in the “about” section:
“I look at the organizations that propagate climate science disinformation and the public relations professionals who have worked behind the scenes to ensure maximum impact of that disinformation.”
It seems you already presume any form of critical scepticism towards scaremongering interpretation of very uncertain scientific data (or data providing various results dependent on slightest input change) is “disinformation”.
I do not think this is appropriate assumption – I would rather think you are biased and effectively filter discussion when it turns into “wrong” direction.
Regards,
[DC: I don’t “presume” or “assume” anything. Rather my assertions were based on two years of researching astroturf organizations like Friends of Science, think tanks Fraser Institute and deceptive ol-industry funded PR operatives like Tom Harris and Morten Paulsen. After six months or so of blogging, I’ve seen nothing to change my initial assessment.]
Then I would really like to know how actually you did come to the point when you believe that we have strong and convincing evidence for future climate scenario (so that immediate and counter-reaction of massive cost in needed to save the climate) while myself got to the conclusion that all predictions are based on extremely non-linear models what generate significant varations in their results dependent on slightest change of their input data and the model itself?
[DC: Sigh … I’m letting through the first part of your comment, against my better judgment. The details you bring up are way off topic, though, as you have already been warned.
I have read several chapters of IPCC TAR and AR4, which are fairly conservative summaries of the science, and have made a point of absorbing specific papers of interest to me. As well, I have examined the “skeptic” arguments in some detail, and not one holds up to scrutiny (and that includes the latest kerfuffle concerning the selection of emails stolen from CRU). In fact, I consider the intellectual dishonesty and vacuity on the skeptic side as a major corroboration of climate science.
But, for the last time, I am not interested in discussing the overall state of climate science on this thread. So further comments along these lines, including oblique or explicit references to the CRU hack will be edited or deleted.
And, yes, I will be posting on specific aspects of the CRU hack. You’ll just have to be patient for a little longer.]
OK, honestly – I am not “sceptic” in a common sense. I do not deny Global Warming nor scientific scrutiny of the GW advocates.
Anyway – I see some bias in the discussion on the subject:
1) Annoying trend to neglect the meaning of MWP or even the actual existence of such a warm period in the past.
[DC: The MWP has been discussed in detail in the IPCC reports.
I have no idea what you mean by “scientific scrutiny” of the GW advocates. Perhaps you could cite some relevant papers or at least a raise a specific issue.
The rest of your points are off topic. ]
Mann et al. (2009) just published an article you might like to read. If you cannot get Science then go to:
http://www.skepticalscience.com/Was-there-a-Medieval-Warm-Period.html
Scott,
This article missess many new finings and is completely biased!
Specifically I mean the following readings:
http://rstb.royalsocietypublishing.org/content/363/1501/2269.full
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/ljungqvist2009/ljungqvist2009recons.txt
http://www.springerlink.com/content/c1411j3532u1n241
http://www.agu.org/pubs/crossref/2009/2009GL037375.shtml
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WH8-4N6Y5S4-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1118491268&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=2643629537af9d6d9e2c9648d72fd4ad
Nope – dozens of new findings show clearly MWP was a global phenomenon and it is stygmatic global warming advocats first denied it’s existence and now try to put it into “local” frame.
Funny “local” indded – spead through 5 continents :-)))
Your cites are somewhat, shall we say, lacking.
The first cite, to Briffa et. al. 2008 in no way contradicts the Mann article.
The second cite is to a collection of raw paleo data. Huh?
The Esper paper presents an opinion which may have been correct at the time the paper was written (or may not have been correct) in the wake of the release of AR4. The Mann result does not make this paper incorrect, nor does it make the Mann result incorrect. All we can say at this time is that the jury is still out.
The fourth cite says that the climate was humid during the time frame of the MWP, not that the climate was warm (chalk up one for Mann).
The final paper has nothing at all to do with climate. Rather it seems to be looking at the efficacy of a particular mite as a proxy for human population levels.
I suggest you bone up on the research and come back with papers which make your point better.
re “It’s time for scientists to ponder how to respond effectively.”
The assault on climate-change science is beginning to resemble a DNS attack, and there’s no question it’s very effective in fora where formal rules of evidence and the right of cross-examination do not apply.
Where such conditions ARE enforced, science can more than hold its own: consider the Dover evolution case of a few years ago.
We know the denialosphere has deep pockets – to which we unwillingly contribute every time we buy gas for the car; perhaps it’s time to spread the wealth.
Are there any lawyers out there who can explain why unjustified comments accusing scientists – either as individuals or organizations – of fraud cannot be tried for libel?
[DC: I’m not a lawyer, so I’ll defer to those with more expertise. However, in most jurisdictions libel is not a criminal offence. Rather it is a question of civil law, and only the persons or organizations who were libelled would have standing to bring an action. Libel laws, and therefore chances for success, vary greatly from country to country.]
Rattus,
You play a nasty game – whatever you want to tell sounds like you are not on the position to accept what “raw paleo data” taken from all around the globe show:
The records show an amplitude between maximum and minimum temperatures during the past two millennia on centennial timescales ranging from c. 0.5 to 4°C and averaging c. 1.5–2°C for both high and low latitudes, although these variations are not always occurring synchronous. Both the Medieval Warm Period, the Little Ice Age and the 20th century warming are clearly visible.
[DC: The paper is here:
http://www3.interscience.wiley.com/journal/122225084/abstract?CRETRY=1&SRETRY=0
ORIGINAL REFERENCE:
Ljungqvist, F.C. 2009.
Temperature proxy records covering the last two millennia:
a tabular and visual overview.
Geografiska Annaler: Physical Geography, Vol. 91A, pp. 11-29.
However, there is no temperature reconstruction or analysis of the temperature proxies. So this paper does not address the question of MWP vs recent temperature, nor does it contradict Mann et al. 2009.
Rest of the comment is off topic and has been removed per comment policy.]
A better link is here.
I have to say that I am rather underwhelmed by the paper. The author bases his discussion, which does not contradict Mann, et. al. 2009, on 71 proxies. Mann used ~1200 proxies with greater geographical distribution. I have to say that I would take an actual analysis of the data vs. the eyeballing approach taken in this rather weak paper.