UPDATE: The Climate Audit server is getting hit with heavy traffic and is slow. If anyone has referenced graphs in blog posts or news articles lease see the mirrored URL list for the graphs at the end of this article and please consider replacement in your posting. I’ve also got a mirrored article of the Climate Audit post from Steve McIntyre. -Anthony
UPDATE2: Related articles
Update: A zoomed look at the broken hockey stick
A look at treemometers and tree ring growth
===
We’ve always suspected that Mann’s tree ring proxies aren’t all they are cracked up to be. The graph below is stunning in it’s message and I’m pleased to present it to WUWT readers. I’m sure the Team is already working up ways to say “it doesn’t matter”.
The QOTW this week centers around this graph:
The quote of the week is:
I hardly know where to begin in terms of commentary on this difference.
– Steve McIntyre, Climate Audit in Yamal: A “Divergence” Problem
The graph above shows what happens to the “Hockey Stick” after additional tree ring data, recently released (after a long and protracted fight over data access) is added to the analysis of Hadley’s archived tree ring data in Yamal, Russia.
All of the sudden, it isn’t the “hottest period in 2000 years” anymore.
Steve writes:
The next graphic compares the RCS chronologies from the two slightly different data sets: red – the RCS chronology calculated from the CRU archive (with the 12 picked cores); black – the RCS chronology calculated using the Schweingruber Yamal sample of living trees instead of the 12 picked trees used in the CRU archive. The difference is breathtaking.
I’ll say. Ding Dong the stick is dead.
This comparison to CRU archive data illustrates the most extreme example of scientific cherry-picking ever seen. As Steve writes in comments at CA:
Also keep in mind the implausibly small size of the current portion of the Yamal archive. It would be one thing if they had only sampled 10 trees and this is what they got. But they selected 10 trees out of a larger population. Because the selection yields such different results from a nearby population sample, there is a compelling prima facie argument that they’ve made biased picks. This is rebuttable. I would welcome hearing the argument on the other side. I’ve notified one dendro of the issue and requested him to assist in the interpretation of the new data (but am not very hopeful that he will speak up.)
See the complete report on this new development in the sordid story of tree ring proxies used for climate interpretation at Climate Audit. And while you are there, please give Steve a hit on the tip jar. With this revelation, he’s earned it.
The next time somebody tells you that tree rings prove we are living in the “hottest period in 2000 years” show them this graph and point them to this Climate Audit article.
Here’s a “cliff’s notes” summary written by Steve’s partner in publication, Ross McKitrick:
Here’s a re-cap of this saga that should make clear the stunning importance of what Steve has found. One point of terminology: a tree ring record from a site is called a chronology, and is made up of tree ring records from individual trees at that site. Multiple tree ring series are combined using standard statistical algorithms that involve detrending and averaging (these methods are not at issue in this thread). A good chronology–good enough for research that is–should have at least 10 trees in it, and typically has much more.
.
1. In a 1995 Nature paper by Briffa, Schweingruber et al., they reported that 1032 was the coldest year of the millennium – right in the middle of the Medieval Warm Period. But the reconstruction depended on 3 short tree ring cores from the Polar Urals whose dating was very problematic. http://www.climateaudit.org/?p=877.
2. In the 1990s, Schweingruber obtained new Polar Urals data with more securely-dated cores for the MWP. Neither Briffa nor Schweingruber published a new Polar Urals chronology using this data. An updated chronology with this data would have yielded a very different picture, namely a warm medieval era and no anomalous 20th century. Rather than using the updated Polar Urals series, Briffa calculated a new chronology from Yamal – one which had an enormous hockey stick shape. After its publication, in virtually every study, Hockey Team members dropped Polar Urals altogether and substituted Briffa’s Yamal series in its place.
http://www.climateaudit.org/?p=528. PS: The exception to this pattern was Esper et al (Science) 2002, which used the combined Polar Urals data. But Esper refused to provide his data. Steve got it in 2006 after extensive quasi-litigation with Science (over 30 email requests and demands).
3. Subsequently, countless studies appeared from the Team that not only used the Yamal data in place of the Polar Urals, but where Yamal had a critical impact on the relative ranking of the 20th century versus the medieval era.
http://www.climateaudit.org/?p=3099
4. Meanwhile Briffa repeatedly refused to release the Yamal measurement data used inhis calculation despite multiple uses of this series at journals that claimed to require data archiving. E.g. http://www.climateaudit.org/?p=542
5. Then one day Briffa et al. published a paper in 2008 using the Yamal series, again without archiving it. However they published in a Phil Tran Royal Soc journal which has strict data sharing rules. Steve got on the case. http://www.climateaudit.org/?p=3266
6. A short time ago, with the help of the journal editors, the data was pried loose and appeared at the CRU web site. http://www.climateaudit.org/?p=7142
7. It turns out that the late 20th century in the Yamal series has only 10 tree ring chronologies after 1990 (5 after 1995), making it too thin a sample to use (according to conventional rules). But the real problem wasn’t that there were only 5-10 late 20th century cores- there must have been a lot more. They were only using a subset of 10 cores as of 1990, but there was no reason to use a small subset. (Had these been randomly selected, this would be a thin sample, but perhaps passable. But it appears that they weren’t randomly selected.)
http://www.climateaudit.org/?p=7142
8. Faced with a sample in the Taymir chronology that likely had 3-4 times as many series as the Yamal chronology, Briffa added in data from other researchers’ samples taken at the Avam site, some 400 km away. He also used data from the Schweingruber sampling program circa 1990, also taken about 400 km from Taymir. Regardless of the merits or otherwise of pooling samples from such disparate locations, this establishes a precedent where Briffa added a Schweingruber site to provide additional samples. This, incidentally, ramped up the hockey-stickness of the (now Avam-) Taymir chronology.
http://www.climateaudit.org/?p=7158
9. Steve thus looked for data from other samples at or near the Yamal site that could have been used to increase the sample size in the Briffa Yamal chronology. He quickly discovered a large set of 34 Schweingruber samples from living trees. Using these instead of the 12 trees in the Briffa (CRU) group that extend to the present yields Figure 2, showing a complete divergence in the 20th century. Thus the Schweingruber data completely contradicts the CRU series. Bear in mind the close collaboration of Schweingruber and Briffa all this time, and their habit of using one another’s data as needed.
10. Combining the CRU and Schweingruber data yields the green line in the 3rd figure above. While it doesn’t go down at the end, neither does it go up, and it yields a medieval era warmer than the present, on the standard interpretation. Thus the key ingredient in a lot of the studies that have been invoked to support the Hockey Stick, namely the Briffa Yamal series (red line above) depends on the influence of a thin subsample of post-1990 chronologies and the exclusion of the (much larger) collection of readily-available Schweingruber data for the same area.
MIRROR URL’s FOR MAIN GRAPHICS IN THE CLIMATE AUDIT POST:
If anyone has referenced the Yamal graphs at CA in blog posts, please use these URL’s so that they get loaded from WordPress high traffic server.
http://wattsupwiththat.files.wordpress.com/2009/09/count_comparison1.gif
http://wattsupwiththat.files.wordpress.com/2009/09/rcs_chronologies_rev2.gif
http://wattsupwiththat.files.wordpress.com/2009/09/rcs_merged_rev2.gif
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Dave Wendt (03:21:43) :
I know that this may come as a shock to you but people actually measured the tree ring widths of the mountain hemlock in the Pacific North West and compared these widths with actual measured temperatures experienced at the sites to come to the scientific conclusion that tree-ring widths (at least for these trees) were good indicator of ambient temperature.
Why are humans so willing to rush after the herd? Just because Steve Mc. shows that one particular tree ring proxy record [all be it an extremely important proxy record] is wrong, it is totally unscientific to then brand all tree-ring width proxies as being shonky.
I sure that Steve Mc. does not believe that we should stop using all tree-ring proxies to measure past temperatures. What (I beleive that) he is saying is that we need to be very careful to rule out other factors, other than temperature, that could have an effect upon tree-ring growth.
And of course, we should always realize that proxy records should always a
little suspect because they are never as good as actual measured temperatures.
Ninderthana nobody said all tree ring data is fraudulent. They said the particular tree ring data which on which Mann’s Hockey Stick theory was, with statistical certainty, not only wrong but deliberately fraudulent.
Scientificaly that is enough, by definition, to discredit the entire catastrophic warming movement who, at the very best, accepted it without attempting verification.
Joel:
“New York Times magazine piece from 2002 in which the CEO John Browne of BP describes how BP exceeded a Kyoto-sized cut in emissions.”
And now that idiot Browne has gone, hasn’t BP done well!
And I’m not even sure what the point is you’re trying to make, other than that Browne is another rent seeker.
Sorry to pick a nit, but how about fixing the “it’s” (should be “its”) in the paragraph below?
It’s getting quoted, e.g. on CCNet.
/Mr Lynn
It was the apparent over-perfection of the Mann Hockey-Stick as pointed out in several convincing climate-science skeptic videos and the revelation that the carbon-dioxide greenhouse effect was self-limited by a logarithmic law of diminishing effect that led me to doubt the scientific validity of the publically accepted global warming theory.
This state of doubt remains even in the face of finding other sources that seem to debunk those videos as being nonscientific propaganda from various industrial and political interests.
All this talk about fake global warming and hockey sticks…I’m getting woody.
Ninderthana–
See the “REPLY: In a nutshell at (20:45:26) above. To selectively include data is not science. To frustrate access to the source data is telling.
Surprisingly, my CIF comment lasted until sometime today – presumably because of a lack of overnight mods.
Not only has it been modded, it’s been completely disappeared. Further sad evidence that a once-honourable newspaper has become an evidence-burying propaganda rag, on some issues at least.
Mann doesn’t need to fight this. He can still be famous. He’s this generations Trofim Lysenko!!!!!!
Neil Craig said at (02:47:18) :
Ninderthana nobody said all tree ring data is fraudulent.
###################
My comments:
Below is the comment by Dave Wendt that ridiculed the use of tree-ring data as temperature proxies. I was responding to that particular post.
I have no dissagreement with the Steve Mc. original post.
###################
Dave Wendt (03:21:43)
Given that tree ring temp proxies tend to be offered with resolution far finer than decadal or centenial time scales, that the only confirmation you offer for the single example you quote is another proxy, of perhaps equally, dubious provenance, that there seems to be mounting evidence that the correlations quoted between various proxies for temps is more a product of the statistical manipulations arising from between the ears of the people constructing the proxies than of anything happening in the real world, and that you failed to address the argument I offered that tree foliage maintaining temp ranges narrower than ambient makes it virtually impossible for a tree to create an accurate record of that ambient temp, I’d have to say you fell miserably short of providing proof for your final assertion.
############
This is a complete load of rubbish.
You are correct Ninderthana I hadn’t spotted that one.
RACookPE1978 (18:51:14) :
I didn’t proofread carefully.
Wilmking and Singh claim that in their research, they
Like you, I consider such intense cherry picking unprofessional, and hence, as I tried to point out below the paragraph, their claim of “eliminating” the divergence, absurd.
Two questions that might be asked: should they get some points for admitting their selectivity? (And) What did the unused 83% of their database show?
Joel Shore (19:59:27) :
philincalifornia says:
When he was accepting the $5-600 million grant from BP at Lawrence Berkeley Labs, Chu’s comments regarding AGW were far different from what they are now. Strangely, although I can’t say I have Googled extensively, links to those press releases do not appear to be readily available.
Well, with your description, it took me about a minute to find this press release: http://berkeley.edu/news/media/releases/2007/02/01_ebi.shtml And, I don’t I don’t see where Chu addresses AGW directly but he talks of “clean sustainable alternative energy sources”.
But, I am also a little confused as to why you think his views would have been different in 2007…The implication seems to be that this would be because he was accepting money from BP.
———————————-
No actually, that would be the wrong implication. I don’t know why his publicly stated views changed.
If you had found the press release(s) I was talking about you would understand, but those releases seem to have disappeared from the net. His position was one shared by many, which is that he didn’t believe the science was settled on AGW, but that even if the AGW theory turned out to be wrong eventually, it would be a mistake not to work right now on, for example biofuels (the subject of the BP grant), in case it turned out to be right. I think you’re going to have a hard time believing that one Joel, but at the time, I was consulting on a cellulosic biofuel program that was funded by another large oil company, so it was my business to absorb such information into my brain.
cross-posted from Tim Blair, I couldn’t resist my own bon mot:
“The Hockey Stick is now re-named the Limp Stick.”
Do spread the word…
George E. Smith (10:38:58) :
DENDO-CHRONOLOGY ?? Isn’t that what tree ringers call their niche of bio-science ?
Hey, George, it is called DENDRO-CHRONOLOGY.
Dendro=tree in greek (same linguistic root btw), so it is “tree chronology”.
I agree that the discipline has been very useful in dating ancient stuff, and also that its use as a universal proxy is unwarranted.
Artwest
Our “evidence-burying propaganda rag” seems to have deleted most of this afternoon’s comments! I have just left one suggesting that this lacks democracy, so I don’t suppose it will be there for long.
Dear old Grauniad – you’d think the arts graduates that run the place would at least have read some George Orwell, but maybe they have and didn’t realise it was satire…
Ninderthana (08:15:04) :
###################
Dave Wendt (03:21:43)
Given that tree ring temp proxies tend to be offered with resolution far finer than decadal or centenial time scales, that the only confirmation you offer for the single example you quote is another proxy, of perhaps equally, dubious provenance, that there seems to be mounting evidence that the correlations quoted between various proxies for temps is more a product of the statistical manipulations arising from between the ears of the people constructing the proxies than of anything happening in the real world, and that you failed to address the argument I offered that tree foliage maintaining temp ranges narrower than ambient makes it virtually impossible for a tree to create an accurate record of that ambient temp, I’d have to say you fell miserably short of providing proof for your final assertion.
############
This is a complete load of rubbish.
Nicely reasoned counterpoint. The paper I referenced is still behind the paywall at Nature, so I’ll have to make do with this quote from UPenn’s press release about its publication;
The research, published online in this week’s Nature, contradicts the longstanding assumption that temperature and relative humidity in an actively photosynthesizing leaf are coupled to ambient air conditions. For decades, scientists studying climate change have measured the oxygen isotope ratio in tree-ring cellulose to determine the ambient temperature and relative humidity of past climates. The assumption in all of these studies was that tree leaf temperatures were equal to ambient temperatures.
Researchers at Penn, using measures of oxygen isotopes and current climate, determined a way to estimate leaf temperature in living trees and as a consequence showed this assumption to be incorrect. This is an unfortunate finding for the potential to reconstruct climate through tree-ring isotope analysis but a boon to ecologists because it creates potential for the reconstruction of tree responses to both average climate and climate change over the last couple of centuries.
In the light of this information and that provided by Anthony in this post
http://wattsupwiththat.com/2009/09/28/a-look-at-treemometers-and-tree-ring-growth/
perhaps you could detail for me the exact mechanism by which you envision a tree managing to encode precise temperature information about the environment where it grows within its growth rings. I’m generally of a skeptical nature but I am always willing to accept new learning if I find it convincing.
What appears to be under discussion here is ‘dendro-thermography,’ a science so new that I find only a few web-hits on this term. My apologies if there is a more official term for this study. I *presume* that the width of each tree-ring primarily indicates how favorable growing conditions were during the year it formed.
That might include the average annual temperature and precipitation, health of the tree, insect attacks, PH of the available moisture, carbon-dioxide concentration in the atmosphere, and the altitude at which any given tree was collected. It may also be possible to do a detailed chemical and isotopic analysis of each ring to further define the conditions that obtained during its growth year.
I make no claim as to knowing the exact methods of analysis or data-reduction being used.
Climate Change doesn’t really matter in terms of the need to transition into a renewable energy economy. Fossil fuels will run out eventually and will keep on increasing in price until they do.
As the debate over warming continues the permafrost melts releasing CO2 and CH4. So even if you win your battle it doesn’t really matter because the war is out of your reach…
Ding Dong the Stick is dead,
the Stick is dead, the Stick is dead,
Ding Dong, the wicked Stick is dead……..in the land of OZ
Anyone hear of cognitive dissonance? The belief amongst the AGW devotees will now strengthen. For same reason that anyone who believes strongly in something will find a way regardless of the facts to continue in that belief. People hate to be wrong.
“”” anna v (12:19:44) :
George E. Smith (10:38:58) :
DENDO-CHRONOLOGY ?? Isn’t that what tree ringers call their niche of bio-science ?
Hey, George, it is called DENDRO-CHRONOLOGY.
Dendro=tree in greek (same linguistic root btw), so it is “tree chronology”.
I agree that the discipline has been very useful in dating ancient stuff, and also that its use as a universal proxy is unwarranted. “””
Thanks Anna; both for the speeling correction, and for the Greek translation; it’s good to know you are out there, to mind our pi-s and rho-s for us.
You see I was thinking in terms of “dendrites” which admittedly does have the rho in it; but is dendrite derived from the same Greek root as tree ?
Learn something new every day at Anthony’s Playpen.
Spector (14:29:22)
My previous point was a disagreement with ring proxies for Temps. Given the dozens of factors in play for tree ‘growth’, and the tendency of any environment to differentiate in very noticeable ways, though the area may be small (see ‘clos’), the short length of this tree’s cycle can represent one tenth of the ‘available time’ for growth in its niche, working rather robustly to eliminate the possibility of a ‘generalized’ datum for a substantial area. In essence, one may as well define a growth ring as indicative of soil aeration due to subterranean nematodes. That vector not well dispersed, as well.
Let me quote from an email to a colleague with the link to this article:
“I will criticize these guys for their lack of lucid conclusions. You have to catch the drift out of the entire article to see the glaring truth.”
I have seen the light, but I am a hopeless old science-nerd. Not everybody is, but they will put it together if you spell it out at the end. They will look back at the graphs and say “AHA, I see what he means!”
Good summary here:
http://www.theregister.co.uk/2009/09/29/yamal_scandal/
Nice to see in it something approaching MSM!