The struggles of Mother Jones fact checker, Jaeah Lee, (see video here) to locate the “decline” in the IPCC assessment report is an object lesson in the effectiveness of the IPCC’s strategy to hide the decline. That she ultimately succumbs to bafflegab from Keith Briffa, declaring “case closed”, is not the main lesson of her video. The main lesson is the success of IPCC’s efforts to hide the decline, even from a fact checker looking for the decline.
The efforts of a young and inexperienced fact checker contrast with the negligent failure of the “seven inquiries” to do likewise. Consider for a moment that none of these reports contained an analysis of “hide the decline” that answered the reasonable questions of the most junior fact checker. None of them even contained a graphic showing hide the decline.
While Jaeah made a few mis-steps along the way and unwisely relied on Mann and Briffa as sources, her struggles to figure out the meaning of Hide the Decline are an object lesson that should embarrass the climate science community.
Jaeah begins her story about trying to find the decline:
We thought it would be easy. Boy, were we wrong.
She then gives a short description of proxies and says:
We put on our magnifying glasses and set out in search of the data….
Like me some years ago (or anyone else), she began her quest with the 2001 IPCC Report:
Figure 1. IPCC Figure shown in MJ presentation.
She couldn’t find the decline in this figure and asked “where was the so-called decline”?
We started out with the 2001 IPCC report, the leading authority… This graph illustrated historical temperatures…… All of these lines told more or less the same story. That starting in the 20th century, the earth warmed at an unprecedented rate. But where was the so-called decline?
Here Jaeah provides vivid testimony on IPCC’s success in hiding the decline. Climategate emails show that IPCC authors were worried that showing the Briffa reconstruction (with the decline) would “dilute” their message. Jaeah’s impression of the IPCC graphic is testimony to their success in hiding the decline. Defenders have argued that the decline is reported in specialist literature and that interested readers could learn about the decline there. But that wasn’t what Jaeah did. She got the desired impression: “All of these lines told more or less the same story.” This was the fundamental deception of Hide the Decline.
Six years ago, having read about the decline (indeed Briffa’s absurd cargo cult was one of the factors that led me into the field), I wondered the same thing about the IPCC graphic – where was the decline – see CA post here, leading me to do a blowup of the graphic, only then discovering that there had been an unreported deletion of post-1960 in the IPCC graphic.
But back to Jaeah’s story. She asked scientists for data and “the more we dug for the answers , the more we grew confused.” She reports:
Several scientists sent us data sets. One started to showed a decline, but the data ended in 1960. We emailed Mann, the originator of the graph. … Mann said that we were looking at the wrong tree ring sets and pointed us to an article published in 2002 in Science. When we plotted this data set, we saw a clear decline around 1960 but still had no idea what happened after 1960.
Here Jaeah is experiencing one part of the frustration in trying to deal with the Team, but she didn’t get the Full Monty treatment. The Team sent her data without her having to resort to a Freedom of Information request. They also tried to answer her questions. However, even with full Team cooperation, the data that she was sent didn’t show the decline, as seen in the next figure, which is a screenshot of her plot of the data that she was sent. It can be conclusively identified as the (truncated) Briffa et al 2001 reconstruction as archived (see here) up to and including the deletion of data after 1960. In their graphic, they’ve added 14 deg C to the archived version (which is in anomaly deg C). The graphic below plots the archived version plus 13 deg C (the overlay at 14 deg C is exact.) For her smooth, Jaeah used a 40-year rolling average (rather than the gaussian smooth that Briffa normally used). My quick experiments indicate that this was done using forward values (rather than centered), without padding, but all available values – thus the smooth extends into the 1990s, although the underlying Briffa version ended in 1960.
Figure 1. Motherjones starting point. Red- as plotted by MJ. Black- Briffa et al 2001 version plus 13 deg C.
As she noted, Jaeah could not locate the decline in this data. This is not surprising. The decline had been deleted from the data. (Looking forward a little here, the Climategate letters were the first time that data after 1960 became available for the Briffa et al 2001 reconstruction – as reported shortly after Climategate at CA here.)
Frustrated, Jaeah turned to Mann for clarificationm who, as noted above, told her that they were looking at the “wrong tree ring sets”, directing them to Briffa and Osborn (Science 2002). Jaeah extracted this data set and showed it in her video as shown below, observing:
When we plotted this data set, we saw a clear decline around 1960 but still had no idea what happened after 1960.
Here Jaeah’s task is complicated by the Gang Who Can’t Shoot Straight. She extracted the Briffa version from the graphic in Briffa and Osborn (Science 2002), but this version is actually identical to the version that she started with. So there’s no difference. Mann’s claim that she had used the “wrong data” is the Gang not shooting straight. In the figure below, I show a gaussian smooth of the Briffa et al 2001 data. Up to a displacement, the two series are evidently the same. So the reason why the Briffa and Osborn 2002 version still didn’t show the decline was that the decline had been deleted from it as well.
Figure 2 . Screenshot of Mother Jones version of Briffa series in Briffa and Osborn 2002.
Jaeah, like many of us, was stumped. Then, in language that precisely tracks the very first mention of Climategate, Jaeah says: “a miracle happened.” The miracle was that they “received a letter from Briffa”. An explanation from the Team – a miracle indeed. Cynics might observe that this sort of miracle only seems to happen to the faithful.
Jaeah recounts her brush with the holy as follows:
He explained that the particular sample did show a decline after 1960 possibly due to increased exposure to carbon dioxide. But that sample data was computed in a way that wasn’t scientifically useful. Meaning basically that all the fuss over the decline came from one obscure data set showing tree ring densities in high latitude regions.
At this point, Jaeah, apparently overcome by the miracle, seems to have swooned and ceased checking facts. To my knowledge, no one has ever suggested that additional carbon dioxide caused a decline after 1960. Nor is there any scientific reason why it should. On the contrary, there is considerable evidence that carbon dioxide increases plant growth; indeed, the anomalous growth of Graybill’s bristlecones – which are integral ingredients in the Mann et al 19998-99 and many subsequent reconstructions – was attributed by Graybill and Idso to increased carbon dioxide.
Nor was the Briffa reconstruction based on “one obscure” data set. The decline was observed in an extremely large data set (389 sites in the Schweingruber network) covering the Northern Hemisphere that had been selected ex ante as being temperature dependent. In fact, the data sets that didn’t show the decline were the ones that were more vulnerable to small and problematic data sets i.e. Yamal and bristlecones, described in the past at CA as respectively cocaine and heroin for paleoclimatologists, who are addicted to these proxies.
Jaeah continues:
When that data was computed in one specific way, that formula gave scientists the wrong idea about the earth’s climate. When they realized it, they stopped using that formula on tree ring for temperatures after 1960. And relied on things like say actual recorded temperatures.
Jaeah’s final graphic is entitled “Briffa post 1960 data finally” and, as shown below, includes data after 1960. Presumably this was included in the “miracle” email from Briffa, though Jaeah didn’t say. As CA readers know, post-1960 Briffa data was first obtained in a Climategate email shortly after the IPCC Lead Authors meeting in Arusha (this version is plotted below.) The Mother Jones version looks related, but the scale looks a little different.
Figure 3. Mother Jones “Finally” with Climategate version (light grey). Smooth as described above. 1960 shown in dotted red.
Jaeah’s conclusion is not warranted from the facts. She states:
so really the mystery of the decline was no mystery at all. Just a messy debate resulting from poor communication and misinterpretation.
Jaeah’s original puzzlement was why the IPCC report didn’t show the decline – an issue that was not investigated by any of the inquiries. (Thus, Jaeah could not locate an explanation in the inquiries.) While the deletion of adverse data can be traced back to Briffa and Osborn 1999 and Jones et al 1999 (both published in first half 1999), the Climategate emails show serious concern at the IPCC Lead Authors about the Briffa version in the Zero Order Draft (which had both a decline and lower centennial variability). Folland had observed:
But the current diagram with the tree ring only data [i.e. the Briffa reconstruction] somewhat contradicts the multiproxy curve and dilutes the message rather significantly.
Folland added caveats that they wanted the “truth”. Mann replied:
everyone in the room at IPCC was in agreement that this [the Briffa reconstruction] was a problem and a potential distraction/detraction from the reasonably concensus viewpoint we’d like to show w/ the Jones et al and Mann et al series.
Mann continued that he didn’t want to give “fodder” to skeptics:
So, if we show Keith’s series in this plot, we have to comment that “something else” is responsible for the discrepancies in this case. [Perhaps Keith can help us out a bit by explaining the processing that went into the series and the potential factors that might lead to it being “warmer” than the Jones et al and Mann et al series?? We would need to put in a few words in this regard] Otherwise, the skeptics have an field day casting doubt on our ability to understand the factors that influence these estimates and, thus, can undermine faith in the paleoestimates. I don’t think that doubt is scientifically justified, and I’d hate to be the one to have to give it fodder!
The “solution” to the problem eventually adopted by IPCC (whether it was Mann or Briffa or both is not material to the fact that it was some combination) built on the tactic already tested in Briffa and Osborn (Science 1999) – delete the inconvenient bits. This has nothing to do with “poor communication and misinterpretation”. Critics are not misinterpreting what they did. They understand precisely what they did and do not accept it as valid scientific methodology, with Richard Muller speaking sharply on this point.
Jon Stewart’s analysis remains the most acute;
It means nothing…He’s just using a trick to… hide the decline. It’s just scientist-speak for using a standard statistical technique for calibrating data in order to …. trick you…into not knowing about ….the decline.
Climate Audit 
113 Comments
Jaeah should look at one of these two items (ideally, both) to continue her investigation:
1) The lack of any statistical foundation for how any of the multiproxy studies were done, given their non-snooped input data.
2) The key data in virtually all multiproxy studies are based on tree ring sets, all of which show very high between-tree variance (six sigma deviations, as observed by McIntyre). Investigate the claim that this was just one dataset that had problems.
Skeptic John Cook put together the last word on “Hide the decline”:
http://www.skepticalscience.com/Mikes-Nature-trick-hide-the-decline.htm
End of story.
Steve: Cook’s article is not the “last word”. It’s barely the first word. He doesn’t understand it at all. Remember that there are different tricks: Keith’s Science trick, Mike’s Nature trick and Phil’s Combo trick.
Mike,
John Cook has it all wrong. I haven’t the time to set straight all of his misunderstandings. Perhaps Steve will choose to do so or perhaps not. If you had bothered to read ClimateAudit, you would be able to find the errors in Cook’s treatment for yourself.
Briefly, Mike Mann hid the decline first in MBH98, published in Nature. Phil Jones used a similar but slightly different “trick” on Briffa’s data. Both were hiding the divergence because they do not want people to know tree rings are not reliable proxies.
But that is not the end of the story.
Steve: Ron, you don’t have this right either. Hide the decline is really Keith’s Science trick. Mike’s Nature trick was dealing with a slightly different problem. Jones’ Combo trick used both.
I’m sorry for Mike and Ron but Steve’s second correction made me laugh out loud. That’s how we learn.
Mike, Mike –
Just because a website is called “skepticalscience” does not mean that the site is actually skeptical of the current “climate science” consensus.
John Cook, the “skeptic”, also does not show a graph which includes the hidden decline. He spends pages talking about how “hide the decline” and “Mike’s Nature trick” are different things (Duh!) but never shows the post 1960 Briffa decline that was hidden. These guys continue to game the sheeple.
Jaeah looks as a bright, honest and determined girl. I hope she reads this post and pushes her research further ahead.
The paleoclimate science community’s “communication problem” is that they need to learn to stop telling lies and start sharing data.
A lie for the sake of promoting a deeply held religious belief is still a lie.
Yes, this IS a “communication problem”…
Mike Roddy, if you accept John Cook’s obfuscation as the final word, you are not seeing what you think you are seeing. Check ‘The Hockey Stick Illusion’ and you may find John Cook’s ‘Last Word’ is not based on evidence.
For homework Jaeah should read the pertinent posts at Climateaudit. She should have called Steve instead of Mann. Is there a chance of that?
Steve- she called me and I talked to her at some length. Unfortunately she didn’t ask me about the matters in her video. I would have been happy to deal with the things that Mann and Briffa were unable to.
I wonder who Jaeah found more helpful in her quest for the facts – Steve, Michael Mann, or Keith Briffa? I hope that Jaeah will comment, given the analysis available to her here, but (realistically) it may be difficult given her employer.
If Ms Jaeah was fact-checking a story based on research into the Gulf oil spill paid for by BP, I wonder if she would go to the BP-paid scientists – and only the BP-paid scientists – in order to understand what was going on. Or if the article was on GM seed stock, would she restrict herself to questioning Monsanto scientists?
Lesson #1 on fact-checking – you don’t ask the teller if he’s telling the truth.
I stand by John Cook’s analysis. Ron Cram, if you read Cook’s blog post, you will find the post- 1960 tree ring decline, something that has been fully discussed in the journals since 1995. In any case, tree ring proxies are only one of many ways to measure paleoclimate, and there is solid agreement among all of the other proxies and temperature records. It is indeed rapidly getting warmer, and humans are mostly responsible.
As for Mike and Ron’s tricks, they were both investigated by several professional scientific bodies- including NAS and NOAA- and exonerated, except for charges of bitchiness and a reluctance to instantly respond to all requests for data (since it was taking up so much of their time).
I recommend Cook’s Skeptical Science for calm and well reasoned analysis of these and related issues. I don’t expect to win converts on this blog, but hope that some of you keep an open mind and investigate the actual climate science in detail.
And I remain open to a debate with Steve on these issues. My age and education are similar, so it would be a more or less level playing field. And I am also open to outlier arguments, including from those who lack full credentials. It should, after all, come down to the hard evidence alone, and our training enables us to evaluate that well enough for a lay audience.
Mike R
John Cook’s blog is one you go to if you want reinforcement for AGW, but not for an in-depth analysis. He leaves out the critical parts.
Re “investigated” and “exonerated”. Sorry, wolves cannot investigate wolves. All those bodies did was issue a statement. Steve has done several posts on all of them – suggest you read them – they are much more thorough and reasoned than anything Cook does.
I have read skeptical science and he has no explaination. He simply asserts, without evidence, that we known that divergance did not occur elsewhere in the tree ring record.
YAWN! Tiring to see insubstantial points again and again. Yeah OJ was also acquitted. At in that case the gloves did not fit. In case of the investigations you cite the glove fitting was not even tried.
I much prefer whitewash to exonerated. I think the investigations claim that they agree that what was done was justified in order to avoid confusing the message. I read this as an admission that the series are basically noise and have zero value in adding substance to the debate. However, I see your mind is already made up on this point.
Mike:
Is there any explanation of the content of your last comment other than that you did not read Steve’s original post above?
And if against all appearance you actually did why did you think it was a good idea to bore us with your boilerplate language about the exoneration by professional scientific bodies without responding to Steve’s critique of the poor quality of those inquiries?
Why would Steve debate you if you don’t read what he writes or ignore it?
How do you expect to “win converts”? By asserting and asserting and asserting?
And what in the world does your puzzling comment about your age have to do with a logical argument?
Please look at figure 1 of Hide the Decline: Sciencemag #3 (https://climateaudit.org/2011/03/23/13321/).
Not only was the decline after 1960 deleted, but the data before 1550 was deleted also. The pre-1550 data “dilutes the message” even more than the post-1960 data. It is a testament to Steve’s persistence that this finally came out more than a decade after publication. It should be an everlasting shame to the Team and its supporters that, to put it kindly, this lack of transparency was so effective for so long.
Steve: In Briffa et al 2001, pre-1550 values are shown. Briffa et al 2001 used principal components instead of averages and got something that looked more like MBH.
Thanks.
lol, yes Mike R……… Nothing says exoneration like, “we were unable to reconcile the divergent accounts [of Solomon versus the NOAA attorneys]”
As far as Cook goes, I believe he’s sincere enough, but his level of understanding the issues of dendrochronology, specifically in regards to the “team” that Steve references isn’t anywhere close to Steve’s. (Nor the average regular reader here.) I would engage, but I don’t see how arguing with Cook by you as proxy for Cook would be productive. If you truly with to understand the issues, you should start at the start right here @ climateaudit. The chronology of the issue is a great read.
I perceive CA as the catalyst of the skeptical movement on the blogosphere. The great irony being as to why it came to be.
I don’t comment much here, but do make it a point to pop by from time to time. CA remains at the top of my bookmark list regardless of the computer I sit at.
Mike Roddy, if you read Steve’s recent post here, you will see why Cook is wrong in his description of Mike’s trick. This is also pointed out to Cook by Jean S in the first comment of the discussion thread.
Mike says: “It is indeed rapidly getting warmer” but that is not the point. Anyone can see that. The question is, do the tree rings work as a good proxy that can be trusted back in time where there are no thermometers to check them with? And if they decline after 1960, then how can we trust them in 1550?
@Craig Loehle –
(This may be a touch O.T.)
Underlying everything else, yes, this is the $64,000 question. It is where my head goes, I know.
And if tree rings aren’t reliable, does that, by extention, apply to other proxies, too? One must at least ask if the other proxies have used tree rings for calibration of their dating. If so, how much DO we know? Anything at all? If sizable divergences in tree ring data can happen even during the instrument period, what hope is there for reading anything into them in the earlier periods?
“My age and education are similar, so it would be a more or less level playing field.”
You flatter yourself. You don’t adress any of the points Steve made, yet you stand by Cook? You’re trying to play squash with SM but you forgot to bring a racquet.
Mike Roddy: if you read Cook’s blog post, you will find the post- 1960 tree ring decline, something that has been fully discussed in the journals since 1995.
Mike, the post-1960 decline is a problem, because it calls into question the general reliability of those tree-rings as proxies for temperature. While the problem was discussed, it was never resolved. Lacking an explanation, Briffa made the assumption that the problem was restricted to the 20th C :
However, there’s a more natural explanation – tree-rings are not reliable temperature proxies, being affected by multiple variables, and they’re complex adaptive organisms whose reactions to changing environments are not sufficiently understood to permit reliable recovery of the past temperatures. (To make it worse, rarely, if ever, do we have a knowledge of the other variables either).
Briffa’s unsupported assumption was used as a reason to keep and use the earlier portion of the series as temperature proxies. Do you recall being informed, , when viewing the decline-hid reconstructions, that they were based on an unproven (and unjustified) assumption?
oneuniverse:
Re: SteveGinIL (Apr 23 12:45),
One thing which sometimes gets lost here is that there is a theory about how tree rings can be a proxy for temperature without the other variables interfering. Basically it says to look for trees living in a place where temperature is the limiting factor. Basically this would be trees near the upper tree line where there is adequate moisture due to snow melt but temperatures will determine how wide the rings will be. It sounds good, but part of the trouble is that the spring temperature increase can be delayed by heavy snowfalls and using things like strip-bark trees introduces a mechanical interference with any actual temperature signal there might be.
OT
This is all ot folks…
Mike,
I can’t speak for any of the US investigations on this, but the UK investigation charged with looking into the science didn’t consider any of the papers in dispute. Nor did it call for evidence from the people disputing the papers, it didn’t have time, the results were out within a month of the “inquiry” starting. So, no, they haven’t been investigated, at least in the three inquiries in the UK. Nor have the allegations of deletion of emails subject to FOI requests, Russell told the Parlimentary ScTech committee he didn’t raise the subject with Jones because it would be tantamount to asking him if he’d committed a crime.
If the post 1960 tree-ring decline is so readily obvious, so thoroughly discussed since 1995, why didn’t the MJ fact-checker pick up on it?
There is an easy way to settle this Mike, do you support a John Cook vs. Steve McIntyre debate?
There’s a degree of mean spiritedness that’s required on the part of the Team to do something like this to a young person who is trying to build a reputation and career in the journalism business. In the emails, the Team took smug comfort from the fact that critics would be unable to develop the level of “sophistication” (to use their word) necessary to figure out what they had done. I disagree. I think even someone without a technical background (like Jaeah) can marshal the “sophistication” necessary if she sets herself to the task. My advice to Jaeah is that she should admit to having been hoodwinked (once) by the Team and now has an opportunity to make her mark by publishing the most hard hitting correction that the world has even seen.
A good place to start is here: http://www.youtube.com/watch?v=8BQpciw8suk (even thought Muller, a fairly sophosticated guy, gets it a bit wrong). Steve can fill in the rest for her.
The young ladies fact checking skills match the science of climatology as it currently is presented.Perhaps her embarassment of being so easily fooled will now produce some real fact checking.Starting with the hacking statement, some fact to support her very first assertion would help establish credibility. Climategate,those pesky emails, a gift that just keeps on giving, must be tough trying to defend the indefensible without realising the error of ones way. Whats next for Mother Earth? That the staff actually read the CRU emails? Cross check public/private statements of the team for this time?Read the FAR summary of science?Fact check the IPCC? Interview M&M as to the background of these emails? Research the scientific method? Thanks for posting the link I needed the laugh.
Steve, if this post is intended to be instructive reading for Jaeah, may I suggest richly hyper-linking the text to your previous posts that contain the actual legwork and substance. As it is, to someone unfamiliar with the body of work at Climate Audit, there’s a risk that it may come across as just a set of assertions.
Very poorly phrased, sorry..! I didn’t mean to imply this post itself lacks substance, only that it is drawn largely from your previous work.
Steve,
“shortly after the IPCC Lead Authors meeting in Aruba”
For Aruba read Arusha? (Tanzania, not Venezuela).
Great post. Fact-checkers often mistake detail for understanding in my experience.
Matt
Steve: 🙂
Aruba is NOT Venezuela; Aruba is an island of the coast of Venezuela and a former dutch colony. Officially autonomously nowadays, Aruba still has strong bonds with the Netherlands (see wikipedia for more details).
Sorry to be Off Topic, but I couldn’t let this one slip.
Wellington, yes, I read Steve’s post, and have been following this entire issue for several years. Here’s an even better guide of the Briffa/Yamal hide the decline hockey stick controversy:
http://www.realclimate.org/index.php/archives/2009/09/hey-ya-mal/
The point is that even if the tree ring proxies have been toyed with- something that would have destroyed the reputations of the IPCC authors involved- it doesn’t make any difference. It’s still getting warmer, as the 20 other non tree ring hockey sticks demonstrate. Tree ring disputes and temperature station questioning are peripheral strategies to destroy the credibility of climate scientists. This method succeeds only among those who have not taken the trouble to study the science in detail.
Steve; the realclimate post is complete disinformation. Take the bristlecones out of the other studies and they are sparse indeed. WHy the climate science community has continued to defend the validty of bristlecone-based reconstructions baffles me.
Mike Roddy says: “as the 20 other non tree ring hockey sticks demonstrate”–this is false if you mean “independent” studies. The multiple studies in the spagetti graphs have overlapping data and mostly depend on a few questionable proxies such as bristlecone pines (about 20 trees with abnormal growth resulting from damage), Yamal larch (a handful of trees with abnormal growth resulting from recovery from shrub form), upside down Tiljander sediments disavowed by the original author as valid in recent centuries due to construction interference with the climate signal, and so on. Without these handful of proxies the shape of the curves changes dramatically in most cases. Why do they insist on using these few trees and refuse to correct the sediment proxy?
And in so doing pull the carpet from under the IPCC….One can only hope.
Mike, if you have a detailed look at the different proxy reconstructions, you will see that they contain several of the same suspect data series (Yamal, bristlecone pines, upside down Tiljander,…), with or without tree rings and are far from independent of each other. If you exchange these few series with some other (equally cherry picked) series, one can show that the MWP was (much) warmer than the current warm period. Simply said, there are too few reliable series before 1600 to warrant any conclusion about the temperatures of the MWP compared to today. And there are essential differences in the different reconstructions: some are HS like with very little variability, others are bathtube like with a huge MWP-LIA difference. In the latter case, the influence of natural variability (solar, internal) is huge and there is little room left for any influence of CO2.
That all has nothing to do with attacking the credibility of climate research, only that these researchers have destroyed their own credibility by cherry picking series, deleting portions of data, replacing undesired data by more convenient ones,… All to hide the decline. If any proxy doesn’t follow the temperature trend today, how can we be sure that that didn’t happen in other warm periods?
Some people in my country were sent to jail, because they did exactly that to hide the decline of their sales for their shareholders…
It is also cherry picking to leave out the bristlecones; the one yamal tree; etc.
In electronics a NTC thermistor varies resistance with temperature. The variation for each part follows a fixed curve. But this varies between devices from the same series. A calibraqtion is required to give an accuracy of better than 5C. A simple straight line fit will do 0 to 70C but the actual shape is a curve. Does this make it wrong to use thermistors as temperature sensors – I hope not!
Use a zener diode of 5v1 rating and the temp coefficient is either +ve or -ve. However each device will always respond the same way to temperature. Is it therefore not possible with calibration to use these to sense temperature?
Also the decline in proxy response was not hidden but openly discussed. PLUS there is obviously no decline in rising temperatures.
The only problem is – does the non linear response from the 60’s negate the previous 200years where they do respond to temp? Then is the previous n00 years where no comparison can be made valid?
I do not think Briffa believes his tree are good thermometers. But what else is there. Sceptics want (quite rightly) proof that the climate is not cyclical but how do you get this – Wait? (perhaps taking the world to a place no one wants) try to use proxies (but this is no proof!!! What else is there?
Ford, your knowledge of science is underwhelming!
So, it’s OK to use proxies which have demonstrable physical characteristics that negate their reliability as proxies not only some of the time, but throughout their entire lifetime. Next, you’ll tell me it’s OK to use the sediments that have been disturbed by human agricultural activities because to do otherwise would be defined as “cherry picking”…
LOL! Nonlinear response???! You call a sudden reversal of the supposed relationship between the proxies and the temperatures a simple case of nonlinear response? In your example, you state that “each device will always respond the same way to temperature”. I assume that you mean that the “device” does not arbitrarily flip that relationship at various times as was the case with the proxies in question so that your example is spurious and does not address any of the concepts involved here.
How about good science?
Ford, the main problem with tree rings is that they have a temperature optimum: below and above the optimum, tree ring growth is smaller than at the optimum temperature (besides other variables like precipitation). Thus if several tree ring series show a negative response to higher temperatures today, how do you know that there were no periods in the past where the temperature was as high or higher than today and the tree rings did respond in the same way with a divergence in the wrong direction?
Strip bark pines are bad proxies anyway: in the same region one can see stumps of trees which did grow above the current treeline, proving that regional temperatures during the MWP were some 3°C higher than today. The strip bark shows only a growth spurt as a response to the stripping, which has nothing to do with local temperature. Even the NAS panel said that strip bark trees shouldn’t be used as temperature proxy. Thus why are these still used in near all reconstructions?
F.E. Agree about the optimum completely. Have said the same myself.
I also agree that this could (if the reason) cause a lack of mwp.
So some trees fail the thermometer test at certain temps.
So how, in a tmely fashion, do you prove AGW or not.
Are you prepared to wait another 50 years for proof – will it be too late??
Energy conservation must be a good thing – vehicles are capable of 40mpg without any problems There is no need (but maybe a desire) for 20mpg vehicles. Which is the sensible path?
snip – blog policies discourage attempts to prove or disprove AGW in three paragraphs
I had absolutely no intention of attempting to prove or disprove AGW in three paragraphs or at all. I was responding to the comment above which seemed to indicate that doing exactly that was a requirement of some kind.
Snip away if you feel its necessary but please don’t mischaracterize what was said to those who can’t read it.
Ford, it is this kind of response that is so infuriating. It is completely possible to agree that energy conservation is a good idea, and also agree that this science wasn’t well done. The two actually have nothing to do with one another.
snip – policy
Ford: the difference between calibrating a thermistor and a treering proxy is that the trees are biological organisms with complex responses. The bristlecones, yamal larch show abnormal growth that makes them suspect–why use them when there are literally thousands of other trees to use? If your thermister calibrated nicely on tuesday but differently when you recalibrated it on wednesday, would you use it?
if there was nothing else I would have to. Suggest a better proxy!
If a proxy is meaningless, it makes no sense to use it. Would you use chicken entrails just because you don’t have a better proxy? There are other proxies that are based on more of a physical chemistry relationship, rather than a biological response, such as mineral ratios in foram in ocean sediments, or cave deposits. These are a little more work to date and have not been studied as much–maybe they deserve more attention.
chicken entrails do not respond to temperature.
I think you would agree that trees do not grow at -40C but grow quite well at 20C Trees respond to temperature (and many other things of course). The entrails are jusat that – entrails!
Good analogy. Split Screen Video:Climate scientists moving tree-ring-bore-cores around on the table puzzling and prodding. Other half, 150 A.D. oracles, moving entrails around on the table puzzling and prodding. I am pretty sure that both methods accuracy are similar.
We’ll skip the ritual disemboweling involved in the second screen.
Re: thefordprefect (Apr 23 09:03),
Who says there is a better proxy? If I suggest I have invented a perpetual motion machine and you find a flaw in it, do I have a right to reply, “Suggest a better perpetual motion machine before I’ll give up on mine!” Proxy temperature reconstructions may just be impossible with the resolution which is necessary to evaluate CAGW.
A better simily: I someone tells the captain of the Titanic the temperature ichanges indicate that there may be icebergs ahead. Should the captain steam full spead until in the dark a lookout spots a berg a few hundred meters away and then take avoiding action or should the captain tell the engine room to make alittle less CO2 (slow up)?
snip – please do not editorialize on policy or economics
Ford, why do you insist on using such simplistic analogies which never quite capture the elements of the situation?
The changes being advocated by the warmist sector can hardly be termed “slowing up”. In your analogy, it would be more appropriately described as the captain removing the engines, refitting the Titanic as a galley and then telling the passengers to row… and all of this based on scant, but exaggerated evidence. Anyway, what makes you believe that we are on the Titanic? 😉
And in fact that is exactly the concern of a lot of people. That a set of scientists believe that there are icebergs ahead, so they carefully construct their conclusions to always be consistent with that belief. They feel it is their moral responsibility. I believe that science works best when it less concerned with political outcomes.
We are in still water. There may be a precipitous waterfall out there. We may be drifting towards it backwards, forwards or sidewayst.We don’t know which direction we should be steaming in, if any. Some passengers claim to have magic binoculars.
How about thousands of other trees with no hockey stick response? Have you ever read any tread on Climate Audit? Abanneh update of the bristlecones? Or Sweingruber’ sites in Siberia with much larger sample than Briffa’s Yamal proxies? And other non-tree ring proxies?
why is it ok to throw away all hockey stick responses??? Is this cherry picking?
When you have one tree out of twelve giving an hs shape, what makes that one tree right and the rest wrong?
Because of Team processing, a few trees out of a large set will procuce a hockey stick. Their algorithm looks for hockey-stickness.
You may want to search the site for earlier discussions of this
phenomena.
As I recall, the McIntyre processing produced vague hockey sticks of miniscule amplitude from red noise.
As I have said many times before (and been told its cherry picking) we have reasonably accurate temperature record of the last 200+ years, trees that do not respond to temperature sufficiently can be weeded out. Already trees that are in the tropics are not sampled (weeds) most non stressed trees are not sampled (weeds), trees of the wrong species are not sampled (weeds).
Some time ago I showed that by taking photos in light levels below the capability of the CCD sensor and adding them the noise from random thermal effects can be removed. I know what the camera was pointing at (the 200 year temperature record) I therefore know I can throw away the invalid photos (non responding trees) – What would be the point in incorporating photos of obvious different subjects, that will not help to extract the real picture (temperature) from the noise. This is not cherry picking – this is using intelligence!
Re: thefordprefect (Apr 24 05:46),
What you failed to grasp from your photo demonstration is that in this case we are trying to pull an unknown signal out of the noise.
Simplest example is found in the stripbark BCP’s (bristlecone pines for newbies). Go review the Almagre story again (categories on the left).
With stripbarks, we showed the ‘signal’ varies by 300%+ depending on exactly where you take the core sample. And there is plenty of visual evidence that maybe, just maybe, the measured high-growth pulse might be related to trees’ response to the mechanical bark stripping: no surprise that when most of a tree’s bark is stripped away, all its growth is focused on the narrow remaining strip.
Even more interesting: the nearby non-stripbark trees don’t show the “signal.”
Bottom line: the surmise that those trees are responding to temperature is quite shaky.
Back to your analogy: to make the comparison more valid, let’s make it a whole set of cameras (multiple tree samples), located in a public place, and you don’t get to watch them (trees were growing under unknown conditions over the centuries). During the month of shooting, the cameras are sometimes adjusted or moved by forces unknown (stripbark, landslides, lightning strikes). Some cameras will likely be broken (trees downed and not sampled).
To follow the analogy, when you go to pick up the cameras, the only ones you get to use are the ones that have clearly been interfered with (stripbark). The more extreme the interference, the better. Any camera still in its expected/normal place is ignored.
That’s what has been happening with the focus on stripbark and other anomalous trees.
You recall this incorrectly. Teh red noise hockey sticks were of eh same magnitude as the tree ring hockey sticks
Steve: as happens too often, Ford is simply repeating an absurd talking point that has been too readily accepted by the credulous “community”. In a singular value decomposition, the PCs (left matrix) are constrained to have a sum of squares of 1. Since there are 581 values from 1400-1980, the “amplitude” is necessarily very small in the PCs from red noise (as it is for PCs from tree ring data.) MBH methodology re-scales these to a standard deviation of 1 and then uses them in a regression scheme (the rescaling is actually redundant). Thus it is the shape that matters. I’ve shown that you can “get” similar reconstructions from red noise as from tree ring data.
It’s not a point that’s been claimed by Mann himself, Wahl and Ammann or by the NAS panel or IPCC.
Steve:
It’s theatre of the absurd, climate style. Somehow I can’t help linking this with my face to face encounter with Lord Acton after I’d watched him being questioned by the Parliamentary committee on science and technology on 27th October last year. Soon after I got talking to Professor Calculus in the corridor some UEA media relations expert felt the need to interpose himself and ‘deal with my query’. But by then I’d done what I’d came for – reminded Acton of what he’d said publicly when face to face with Steve in the wine bar after the Guardian debate in July. Had he found the facts Steve had ‘got completely wrong’ on Climate Audit, as promised? Er, no. He’d looked, been unable to locate them and, surprise surprise, not contacted Steve to tell him this. “Are things deleted on the website?” he asked slyly. My time to say, firmly, “No.” And then the PR man was upon us.
The point throughout is that Acton was never meant to be face to face with Steve McIntyre. It’s a vital part of the plan: that Steve only gets to meet the online timewasters peddling the absurd urban legends of climate. A very mediocre Vice Chancellor of UEA having personal interaction with Him Who Shall Not Be Named – that was way out of bounds for the PR gurus of Consensus HQ. We’d all just seen how badly Calculus came off in open debate with McIntyre, with Fred Pearce, Doug Keenan and even George Monbiot helping out.
Thus R. Drake in the privacy of Portcullis House was too much for the good Lord three months later. It’s this inability to face the music at any level that has done such damage to UEA and the Team generally. Thanks gentle host for maintaining dignity and focus despite all of it.
How embarrassing: everything I wrote above was true – except it was Trevor Davies, not Edward Acton! Urban legends indeed. My apologies.
Craig Loehle Apr 23, 2011 at 9:25 AM mentions
” cave deposits. ”
Perhaps you do not mean speleotherms here, but I have filed this quote about stalgmites on my computer under the filename ‘Good Grief!”
quote
A USEFUL STARTING POINT FOR SPELEOTHEM CLIMATE RECONSTRUCTION
IS TO ASSUME THAT:
· every sample has a different response to climate, and that even two stalagmites ten cm apart in the
same cave will have different climate signals.
· that non-linear responses should be expected due to the inherently non-linear hydrology of karst
· deeper, slower dripping samples will show more linear responses, but will also be lagged and
maybe even have no response to surface climate. In contrast, shallow and fast dripping stalagmites will be
very responsive to climate but will be more difficult to calibrate and understand.
· Most climate proxies preserved in stalagmites are a complex mixture of soil, vegetation, rainfall,
evaporation, hydrological and geological processes.
unquote
Lots of wiggle room with those when a quick foray through the different deposits will show teleconnected signals from… well, anywhere you’d care to name. A fitting substitute for tree rings?
Sometimes, when we have no information, it is better to act in accordance with that lack (or not act at all), rather than assume bad information is correct for the sake of something, anything, to excuse our actions.
JF
Okay –
Your assertion here is dead wrong.
First: Bristlecones have been shown to be poor proxies.
Second: Steve M, when he looked at Briffa’s study that included Yamal, he did two things. Steve reconstructed WITHOUT the Yamal, but with the (much larger sampling) nearby Schweingruber sites (which should never have been left out in the first place). The hockey stick disappeared. Steve M then included both Yamal and the Schweingruber cores, and the hockey stick wasn’t there. ONLY when the nearby Schweingruber cores were left out did the hockey stick appear.
Briffa wrote a rebuttal to this, just before Climategate, which was then lost in the brouhaha of Climategate. In it, Briffa misrepresented everything Steve had done. No single “fact” Briffa asserted about Steve M’s reconstructions was true. So far as I know, it is the only rebuttal CRU has come up with, and it is 100% flawed.
Mike, I’ll be aside your delusional assertion about peripheral issues. Though, I would remind you that Mann’s hockey stick was iconic for the warmist agenda. As far as your “It’s still getting warmer..” assertion, I’d have to ask, since when? Compared to what time frame? It gets warmer every day. Every season has a temp change as to years, decades, centuries, eons…..
re: the Gavin’s Hey Yamal post (in relatively happy days for RC before Climategate deflated the tires on their buggy)
Gavin shows the discredited MBH hockey stick, and then seven other graphs (excluding the final one of his name) purporting to show independent support for the hockey stick shape of Mann’s recon.
1. Oerlemans – warming begins ~1850, not ~1900 like the HS.
2. Osborne and Briffa – warming from ~1810 (pre-industrial revolution), not ~1900 like the HS
3. Boreholes – warming from ~1700 – no hockey stick
4. Ice core CO2 concentrations – not a temperature reconstruction, irrelevant
5. Kaufmann 2009 – the study used the Tiljander sediments, not considered a temperature proxy for the period of the ‘blade’ of the hockey stick, in an upside-down orientiation, lending a hockey-stick like uptick to the recon. (Also, if you zoom in to the final segment of the graph, you’ll notice a divergence between the black line (w/ yamal), and blue line (w/out yamal) – the blue line has a much milder rise.)
6. M08 blue line (full network without tree-rings) – there’s nothing visible of the blue line beyond 1820, so no hockey stick is demonstrated
7. HadCRUT3v instrumental record – no hockey stick, as there’s nothing for the preceding centuries – it would needs a flat multi-century ‘shaft’ to make it a hockey stick.
So, in fact none of the graphs are in agreement with the MBH hockey stick (which had 900 years of gentle cooling with little variation, followed by rapid warming in the 20th C).
From Skepticalscience to Realclimate. That is going from the frying pan into the fire. It is now obvious that you either have not read the Climateaudit posts or you do not want to understand them. You should restart with the Hockey Stick debate on the left margin.
Mike: “The point is that even if the tree ring proxies have been toyed with- something that would have destroyed the reputations of the IPCC authors involved- it doesn’t make any difference. It’s still getting warmer, as the 20 other non tree ring hockey sticks demonstrate.”
As a matter of course you should check everything you read in realclimate very carefully before quoting it. If you have a non-tree hockeystick let’s know which one it is, but before you do please be aware that there are literally hundreds of reconstructions that don’t use trees that show a quite distinct MWP.
I don’t believe anyone is saying it isn’t getting warmer, it has been since around 1650 the end of the Little Ice Age. The “hockeystick” wasn’t about it getting warmer it was about the 20th century being unique in getting warmer, thereby tying in (in their usual ham-fisted way) CO2 and CO2 only with the rise in temperature. Which it may be, but the first duty of the scientist is to present the unadulterated data and not manipulate the mathematics to get results they want. Read Andrew Montford’s Hockey Stick Illusion, read it and where you have problems ask realclimate.com to point to what he’s got materially wrong. Better still do pretend to be a sceptic and you will either be censored, or the answers will make you consider what side you’d rather be on, whoever is right.
I wish this Mother Jones author had spent more time looking for the trick rather the decline.
What an utter mismatch it all is: one or two smart Canadians against NASA, the East Anglia, the Royal Society, the National Academy of Sciences, Joe Romm, Charlie Manson, Schwartzenegger, Big Al, and millions more. And the Canadians win, hands down!
Well, Since they issued one correction their text, I imagine people could write them and ask them to correct the video.
Be nice and polite folks
Too bad Mother Jones didn’t go to Wikipedia:
http://en.wikipedia.org/wiki/Climatic_Research_Unit_documents#Climate_reconstruction_graph
There’s some fluff at the start but the discussion and charts are sound. Charts straight from CRU, as it happens, though perhaps not presented quite as they would like .
Cheers — Pete Tillman, who wrote most of the section, ims
Why is it that whenever somebody raises the so called “divergence” issue/problem somebody has to explain that it has been “discussed” before in ivory towers?
When is somebody going to concede that for more than 50% of “the great last 30 years of the hottest years ever on the planet” that they don’t know the answer and that therefore the last 30 years might not actually have been….?
Briffa still has a project running on the subject, due to end in May 12:-
The Dendroclimatic Divergence Phenomenon: reassessment of causes and implications for climate reconstruction
http://www.cru.uea.ac.uk/cru/research/
Scroll to find, there is a project description that I will have to leave to my betters to interpret.
There doesn’t seem to be a link as to where the funding is coming from?
Maybe in a year’s time we will be treated to a tablet of stone?
Without a credible answer or a “we don’t know” (an equably acceptable answer) more and more people will draw the “hidden” conclusion.
The resolution of this issues lies in one direction only.
good finding Green Sand. So a non-problem about an obscure data set has turned into a multi-year research project. Nice.
Great find. I am quite pleasantly impressed with the very frank description. Reading the emails one gets the impression that Briffa wishes he had done that study years ago when divergence was first apparent. Good for him to be pursuing the matter.
‘Dendroclimatic Divergence Phenomenon’ – the well-known but still unresolved late 20th C divergence of dendroclimatology from normal science.
I agree with the others – good find.
I note that Briffa’s project notes/preliminary abstract states:
This roundly refutes waht Briffa told Jaeah (quoting Steve M.):
Briffa refutes himself. It is either “one obscure data set” or it is the problem of “divergence in many tree-ring data sets around the Northern Hemisphere.” Keith, caught in another blow-off of someone trying to get at the facts, threw his “miracle” at Jaeah, and she bought it. It was just one li’l ol’ insignificant data set, not somefin none o’ da unsophisticated Mother Jones readers should trubble demselves wiff.
Green sand –
One more thing about Briffa’s study…
Oneuniverse quoted Briffa above thus:
Thus, it is most likely that Briffa will make some assertion that, yes, there is a divergence – and humans are the cause of it. I’d like to go on record as having predicted this. Briffa is not going to say to the world, “Look, tree rings really aren’t any good as proxies. Sorry, we have to find some other means of reading past temperatures.”
How he will use humans to explain the “Other Divergence Problem” – the pre-1550 one – remains to be seen. I suspect he will blow it off and hope no one notices.
Steve you should put the title in quotes,
Jaeah’s “Investigation”
Steve: As I said in the article, I think that she tried harder than the academic inquiries. Given that academic inquiries with senior people didn’t even try to analyze the problem, why be harsh on someone who at least tried?
That maybe true but her change from “investigator” to one of the faithful after the “miracle” warrants it.
I would give her an A for effort if you she tried to contact you.
I agree with Steve M here. Do give her some credit. She did do more than the inquiries. (I commented about that elsewhere here.) And, Steve, I agree with you being “decent” about it.
Of course, as is pointed out above, Briffa’s explanation makes no sense in the real world (where CO2 actually improves plant growth). But besides not making sense, does the explanation even explain? Does Briffa contend there some huge change in CO2 exposure from 1959 to 1960 and forward? Do trees stop being temp proxies at a certain CO2 concentration? And if the data processing was not “scientifically useful” after 1960 why was it ok before 1960?
I think you have to willfully suspend some critical thinking skills to hear that nonsense and announce “case closed” at the end.
Taking the instrumented period first, in the 20 years or so since the main dendrothermometry papers were written, the pattern of global instrumental temperature has changed, with a visible and probably verifiable flattening since about 1998.
If the same pattern applies to localities where the significant or disputed dendrothermometries arise, then a resampling, recalibration and reinterpretation should be done with the recent temperature series calibrating the tree ring measurements, then extrapolating into past centuries for so long as there are adequate sample numbers.
It has long puzzled me that hockey stick spaghetti graphs show such poor correlations between authors. Let’s recalibrate them all to modern temperatures and let the spaghetti fall as it may. I can so no reason why hockey stick advocates have not done this as a matter of course.
Increasing atmospheric CO2 causes increased growth in trees.
Increasing atmospheric CO2 causes decreased growth in trees.
The ‘real trick’ is to hold such two contrary views and keep a straight face when saying both.
Mac,
It is no problem at all if you expect that no one in the press will question you on the obvious contradiction. The Team uses the press for support and uses ad hominems to attempt to descredit our attempts to get at the truth.
Mac – I don’t know about CO2, but I do know that the same effect can be observed (and demonstrated) with H2O. If your house plant has stopped growing, the two most likely explanations are too much water or too little water.
I can’t find it now, but I DID see recently a graph showing 3 different tree types graphed vs temperature, and on that graph there did seem to be an optimal temperature. Both below and above that temperature tree ring growth dropped off rather quickly. So, it is possible that higher temps DO mean less growth, beyond that optimum temperature.
I thought that graph was here on CA. In the last 2 weeks.
OT
I exchanged a couple of light emails with Jaeah Lee.
Since I expected the Mother Jones piece to be worse than it turned out I was helpful but terse. I pointed her to my previous posts which accurately described events and answered a clarifying question or two, but did not speak to her.
At least Mother Jones has a fact-checker, distinguishing it from the NY Times.
When SteveM discusses the struggles of Mother Jones fact checker, Jaeah Lee, I wonder if he describes her efforts with tongue in cheek. Certainly she lacks the credentials of a technical fact checker and would have to be considered, from the account of her efforts here, rather naive and trusting or, on the other hand, someone who went into her “investigation” with a conclusion in mind and proceeded through the acceptable journalistic motions before she came upon the sought for miracle. I most often settle on just not knowing any better over any motivational influences in matters such as these, but here I am tempted to go with the latter. Miracle indeed.
I wrote my post above without going to the video. After viewing the video, I could only chuckle and wonder how SteveM makes some of his comments with a straight face. Case closed.
Has anyone considered the possibility that temperatures actually did decline abruptly post-1960; and through a process of intercontinental teleconnection taking place at distances measuring thousands of kilometers, these exquisitely sensitive treemometers were able to detect a precipitous decline in temperature over those large areas of the earth’s surface not covered by conventional temperature measurement devices?
I honestly have never gotten what the big deal is here.
Normal procedure would have been to just throw out the diverging data set.
Then, no one would have even known about this at all. Big deal. We have real thermometers for the 1960s.
And, personally, as far as reconstructing paleoclimate, tree rings are probably not the most reliable anyway. I just don’t get why people are making a big deal about it.
For another thing, everyone points to the line in the graph — I sure would be looking at the range of uncertainties (confidence interval). It is quite broad.
Take out the diverging tree rings, leave them in, so what?
Steve – if you take out the tree ring series, you don’t have much left for the canonical reconstructions. Mann’s non-dendro recon uses upside-down Tiljander sediments.
The Team is quite happy to throw out “divergent” dendro series and keep bristlecones and Yamal, there’s no botanical reason why these are magic trees. And in the case of bristlecones, problems with strip bark.
The “big deal” is that the tree rings are needed to make reconstructions that show alarming rates of warming, to get rid of the Medieval Warm Period, and unprecedentedness. These recons are even used to test climate models over the past 1000 yrs. It does not do to just “throw out the diverging data set” because if the trees responded to temperature by growing less after 1960, why not in earlier times, and if these trees, then why not other trees you decided to keep?
snip – OT
snip – OT
I love this.
As rudimentary and naive as Jaeah Lee’s ‘fact check” was, it does seem obvious that it was still miles more in depth than the panel inquiries. Though she didn’t ask any skeptics (the accusers) for what their side of the issue was, she did at least look at the numbers and try to determine what the problem was.
Did she came up short? Yes.
But she did a better job than Oxburgh. Yes, I know. That isn’t saying much, is it? Reading tea leaves would have been better than Oxburgh.
Brilliant, brilliant work. McIntyre deserves the climate science communicator of the year and decades awards. He is the best analyst working in climate science today.
MoJo’s stated value system.
“Principally we’re about good journalism, following a story no matter where it takes us. We are interested in protecting the little guy and uncovering injustice. We also believe in good storytelling and coverage that surprises. We have no interest in preaching to a choir.”
It looks like once Mojo got the answer they were looking for in this journey of theirs they stopped looking further and declared to all and sundry problem solved. They forgot that the ‘little guy’ in all this was scientific integrity and not the scientists who indulged in trickery.
“Normal procedure would have been to just throw out the diverging data set.”
No, proper scientific procedure is to throw away the theory when it diverges from the data…. period. The converse does however allow you to pretend to proove anything you want to gullible people.
We trust this riposte will be forwarded to Mde Shepherd in her MJ cubicle to “read, learn, and inwardly digest.”
On matters of scientific practice and principle, pleading ignorance due to lack of technical expertise is a canard. Purporting to provide a comprehensive, objective overview by spinning verbalisms acceptable to clunking ideologues wastes everybody’s time.
It’s most likely that tree growth slowed due to the stunting properties of tropospheric ozone, even at low background levels:
“Air pollution may cause short-term (acute) damage, which is immediately visible, and long-term (chronic) damage, which can lead to gradual tree decline. Long-term damage may predispose trees to other disorders, making diagnosis difficult.” http://pubs.ext.vt.edu/430/430-022/430-022.html
More links to research here:
http://witsendnj.blogspot.com/2011/07/profound-negative-impacts.html
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