First here is Dr. Keith Briffa’s response in entirety direct from his CRU web page:
My attention has been drawn to a comment by Steve McIntyre on the Climate Audit website relating to the pattern of radial tree growth displayed in the ring-width chronology “Yamal” that I first published in Briffa (2000). The substantive implication of McIntyre’s comment (made explicitly in subsequent postings by others) is that the recent data that make up this chronology (i.e. the ring-width measurements from living trees) were purposely selected by me from among a larger available data set, specifically because they exhibited recent growth increases.
This is not the case. The Yamal tree-ring chronology (see also Briffa and Osborn 2002, Briffa et al. 2008) was based on the application of a tree-ring processing method applied to the same set of composite sub-fossil and living-tree ring-width measurements provided to me by Rashit Hantemirov and Stepan Shiyatov which forms the basis of a chronology they published (Hantemirov and Shiyatov 2002). In their work they traditionally applied a data processing method (corridor standardisation) that does not preserve evidence of long timescale growth changes. My application of the Regional Curve Standardisation method to these same data was intended to better represent the multi-decadal to centennial growth variations necessary to infer the longer-term variability in average summer temperatures in the Yamal region: to provide a direct comparison with the chronology produced by Hantemirov and Shiyatov.
These authors state that their data (derived mainly from measurements of relic wood dating back over more than 2,000 years) included 17 ring-width series derived from living trees that were between 200-400 years old. These recent data included measurements from at least 3 different locations in the Yamal region. In his piece, McIntyre replaces a number (12) of these original measurement series with more data (34 series) from a single location (not one of the above) within the Yamal region, at which the trees apparently do not show the same overall growth increase registered in our data.
The basis for McIntyre’s selection of which of our (i.e. Hantemirov and Shiyatov’s) data to exclude and which to use in replacement is not clear but his version of the chronology shows lower relative growth in recent decades than is displayed in my original chronology. He offers no justification for excluding the original data; and in one version of the chronology where he retains them, he appears to give them inappropriate low weights. I note that McIntyre qualifies the presentation of his version(s) of the chronology by reference to a number of valid points that require further investigation. Subsequent postings appear to pay no heed to these caveats. Whether the McIntyre version is any more robust a representation of regional tree growth in Yamal than my original, remains to be established.
My colleagues and I are working to develop methods that are capable of expressing robust evidence of climate changes using tree-ring data. We do not select tree-core samples based on comparison with climate data. Chronologies are constructed independently and are subsequently compared with climate data to measure the association and quantify the reliability of using the tree-ring data as a proxy for temperature variations.
We have not yet had a chance to explore the details of McIntyre’s analysis or its implication for temperature reconstruction at Yamal but we have done considerably more analyses exploring chronology production and temperature calibration that have relevance to this issue but they are not yet published. I do not believe that McIntyre’s preliminary post provides sufficient evidence to doubt the reality of unusually high summer temperatures in the last decades of the 20th century.
We will expand on this initial comment on the McIntyre posting when we have had a chance to review the details of his work.
K.R. Briffa
30 Sept 2009
- Briffa, K. R. 2000. Annual climate variability in the Holocene: interpreting the message of ancient trees. Quaternary Science Reviews 19:87-105.
- Briffa, K. R., and T. J. Osborn. 2002. Paleoclimate – Blowing hot and cold. Science 295:2227-2228.
- Briffa, K. R., V. V. Shishov, T. M. Melvin, E. A. Vaganov, H. Grudd, R. M. Hantemirov, M. Eronen, and M. M. Naurzbaev. 2008. Trends in recent temperature and radial tree growth spanning 2000 years across northwest Eurasia. Philosophical Transactions of the Royal Society B-Biological Sciences 363:2271-2284.
- Hantemirov, R. M., and S. G. Shiyatov. 2002. A continuous multimillennial ring-width chronology in Yamal, northwestern Siberia. Holocene 12:717-726.
Now a few points of my own:
1. Plotting the entire Hantemirov and Shiyatov data set, as I’ve done here, shows it to be almost flat not only in the late 20th century, but through much of its period.
How do you explain why your small set of 10 trees shows a late 20th century spike while the majority of Hantemirov and Shiyatov data does not? You write in your rebuttal:
“He offers no justification for excluding the original data; and in one version of the chronology where he retains them, he appears to give them inappropriate low weights.”
Justify your own method of selecting 10 trees out of a much larger data set. You’ve failed to do that. That’s the million dollar question.
Briffa Writes: “My application of the Regional Curve Standardisation method to these same data was intended to better represent the multi-decadal to centennial growth variations necessary to infer the longer-term variability in average summer temperatures in the Yamal region: to provide a direct comparison with the chronology produced by Hantemirov and Shiyatov.”
OK Fair enough, but why not do it for the entire data set, why only a small subset?
2. It appears that your results are heavily influenced by a single tree, as Steve McIntyre has just demonstrated here.
As McIntyre points out: “YAD061 reaches 8 sigma and is the most influential tree in the world.”
Seems like an outlier to me when you have one tree that can skew the entire climate record. Explain yourself on why you failed to catch this.
3. Why the hell did you wait 10 years to release the data? You did yourself no favors by deferring reasonable requests to archive data to enable replication. It was only when you became backed into a corner by The Royal Society that you made the data available. Your delays and roadblocks (such as providing an antique data format of the punched card era), plus refusing to provide metadata says more about your integrity than the data itself. Your actions make it appear that you did not want to release the data at all. Your actions are not consistent with the actions of the vast majority of scientists worldwide when asked for data for replication purposes. Making data available on paper publication for replication is the basis of proper science, which is why The Royal Society called you to task.
Read about it here
Yet while it takes years to produce your data despite repeated requests, you can mount a response to Steve McIntyre’s findings on that data in a couple of days, through illness even.
Do I believe Dr. Keith Briffa? No.
Sponsored IT training links:
Guaranteed success in NS0-154 exam with help of 650-177 practice test and up to date 642-515 exam dumps.
One of the advances in silviculture I’ve been waiting for is sterile trees. A lot of the reduction in growth for old wood is due to production of seed. If you could eliminate this, you’d get more wood, less pine cones.
Every now and then a tree naturally appears that is sterile and they grow unnaturally quickly at old age. A famous example was the “golden spruce”, or Kiidk’yaas about which a book was written. It had yellow needles which reduced its efficiency at photosynthesis, but since it was also sterile, it grew fairly quickly.
Tried to post a note to RC about taking a look at these sets of tree ring data before they dig themselves farther into a hole
http://www.climatedata.info/Proxy/Proxy/treerings_introduction.html
or look at long term temperatures
http://www.rimfrost.no/
but it was to much for the “gatekeeper”. I guess they don’t like me.
Leif Svalgaard said:
“Although YAD061 looks like an outlier, the other trees do show a rise from ~1820 to today [albeit smaller] so the record [based on those threes] does not look entirely flat to me.”
I agree, but what does the rest of the series show? From seeing these individual trees, all from the same area displayed above, I conclude that any interpretation can be put on any collection depending on the results desired. All data available must to used to balance the picture with only the outliers excluded, i.e. depending on the sample size you through out the top x and bottom y samples before calculating.
In this case he’s kept the data secret long enough that CO2 changes will be implemented as desired because of the wide use of this data influencing many other reports.
“10 years on Dr Briffa says he and his colleagues are working to improve the robustness of the results showing that tree ring data reflects climate change!
He has been working for teny ears, not to improve the robustness of the results, except in the negative sense, by refusing to yield the data he is protecting the claimed robustness from being exposed as not robust.
fix typo please, ten, not teny
The gig’s up:
http://bishophill.squarespace.com/blog/2009/9/29/the-yamal-implosion.html
Gary (09:55:37) :
“OK, regardless of hard feeling about past behaviors, real and imagined… Extracting a pound of flesh, as Shylock learned, isn’t without its costs. By all means the debade should be open and rigorous, but this reply has little if any nastiness and ought to be treated fairly.”
Reasonable point Gary. Except that Briffa writes with the clarity of a PR obfuscationist. And in doing so leaves the ad homs and “nastiness” to the RC Team. There, nastiness, ridicule and condescension toward skeptics remain the Team mandate.
Mr. Briffa and his defenders need to respond not only to the data manipulation charge – but also to the stonewall charge. There is little doubt that the years of delays and impediment to review have made their whole enterprise more than a little suspect.
Briffa is at the CRU, where the climate models that fueled the whole AGW (choose your noun of preference) started. The climate modelers needed evidence that substantiated the assumptions and conclusions of their models. Briffa obliged.
Which is not to say Briffa deliberately misrepresented the data or conclusions. Whenever post hoc selection of data occurs, so does confirmation bias.
As noted above, dendro studies need randomized sampling to have any scientific validity.
Since this won’t get posted at RC, I might as well post it here. The reason this event is so damaging to AGW science is that a dozen or so proxy studies were based on Yamal data that was processed, not raw. Basing a proxy study on raw data is acceptable, but basing it on data that has been filtered and then smoothed is not. Briffa’s withholding of his data is poor practice but his choice. But the further use of his processed results is inexcusable.
I have posted two comments on RC. It seems only one was posted. I am disappointed on the quality of debate RC allows.
As a layman, i am very disappointed by the quality of the rebuttal on this issue by the pro-AGW.
Bret (14:24:18)
Take 1000 cores and find 10 with a hockey stick shape? All that says is you found 10 hockey stick shaped cores because the trees were fertilized, segregated, better watered, etc.
But take 1000 cores and get 1000 hockey sticks? Now you have something. Take 1000 in 10 places around the world and get 10k hockey sticks? now you really have something.
Also matching to the instrument record is tenuous at best seeing the measurement bias. When you restrict the instrument record to just a few locations near the trees, you have an even better chance of UHI or something similar.
black humour: “In the Wild West they’d find a tree and…”
Correction to my previous post, 100% hockey sticks is not necessary at all, but a majority would be significant. But my previous point of selecting individual cores based on a correlation to the instrument record still stands. It is no more valid than matching them up to CO2 (which some do) or rainfall (which some do) or the number of sparrows in Rosslyn VA (which some do too). With a big enough set to sample from you can always get matches to anything.
If Briffa explains that these 10 trees were selected completely randomly from a much larger number of cores, that would be satisfying, at least for that location. Then that process would need to be repeated at many other locations around the world.
“The substantive implication of McIntyre’s comment (made explicitly in subsequent postings by others) is that the recent data that make up this chronology (i.e. the ring-width measurements from living trees) were purposely selected by me from among a larger available data set, specifically because they exhibited recent growth increases.”
Yes, and I still believe it now.
@ur momisugly P Wilson (11:46:42) :
Boreholes go back much further than 500 years. This study goes back 2,000 years:
Huang, S. P., H. N. Pollack, and P.-Y. Shen (2008). A late quaternary climate reconstruction based on borehole heat flux data, borehole temperature data, and the instrumental record, Geophys. Res. Lett., 35, L13703, doi:10.1029/2008GL034187.
Here is an image from that article (striking isn’t it?):
http://www2.sunysuffolk.edu/mandias/global_warming/images/borehole_3.gif
Figure 7d (Huang, Pollack, and Shen, 2008) shows the following: a broad cool minimum around AD 200 that was followed by a warming that peaked AD 1200–1400; the Medieval Warm Period (MWP)), a subsequent cooling to a minimum around (AD 1700–1800; the Little Ice Age (LIA), followed by rapid and substantial warming in the past few centuries. The reconstructed peak temperatures in the MWP appear comparable to the AD 1961–1990 mean reference level, with the bold mid-range curve slightly below. None of the borehole reconstructions show MWP peak temperatures as high as late 20th century temperatures, consistent with the conclusions of both National Research Council (2006) and Intergovernmental Panel on Climate Change (2007) about the warmth of the MWP. The LIA temperature minimum shows an amplitude about 1.2 K below the MWP maximum, and about 1.7 K below present-day temperatures.
@ur momisugly Scott A. Mandia (11:49:39) :
Anthony’s reply: Not all – check the latest main page story. Too much money flowing around uncontrolled in our government science programs apparently, you’re just on the low end of the totem pole. – A
No problem, tomorrow night’s Mega Millions jackpot is $44.2 million after state and federal taxes. I will be posting from Hawaii on Saturday! 🙂
@ur momisugly Tim Clark (11:56:42) :
Huh? I said “regardless of proxy” which means corals, sediments, cave deposits, boreholes, ice cores, etc. NOT just tree rings.
@ur momisugly kim (12:00:53) :
I have to admit I love your passion but not your statements. If you were a scientist you would understand how we think and that it goes against our nature to have “group think.” There may be exceptions but it certainly is not the rule.
The Nobel Prize goes to the first person that can show why we are all wrong about AGW. That is quite an incentive. Ah, but to have one’s name said along with Galileo, Darwin, and Einstein…..
@ur momisugly brazil84 (12:02:21) :
The fact is that the hockey stick DOES NOT keep appearing regardless of proxies and study authors.
Wrong.
@ur momisugly jlc (12:47:02) :
Look at borehole data. It is quite compelling. I have a link and some references for you:
http://www2.sunysuffolk.edu/mandias/global_warming/determining_climate_record.html
Huang, S. (2009). Brief introduction to the geothermal approach of climate reconstruction. Retrieved September 20, 2009 from Borehole
Temperature and Climate Reconstruction Database: http://www.geo.lsa.umich.edu/climate/approach.html
Huang, S. P., H. N. Pollack, and P.-Y. Shen (2008). A late quaternary climate reconstruction based on borehole heat flux data, borehole temperature data, and the instrumental record, Geophys. Res. Lett., 35, L13703, doi:10.1029/2008GL034187.
Pollock, H. (2005, December). Reconstruction of ground surface temperature history from borehole temperature profiles. Retrieved September 29, 2009, from http://home.badc.rl.ac.uk/mjuckes/mitrie_files/docs/mitrie_borehole.pdf
Tamino. (2007, May). Notes from Underground. Retrieved September 20, 2009 from Open Mind Website: http://tamino.wordpress.com/2007/05/20/notes-from-underground/
@ur momisugly Peter Plail (13:09:14) :
It seems to me that, at the moment, the entire edifice of US and European environmental and economic policy if balanced precariously on a few Siberian treestumps
Peter, step back a second. Do you really believe that thousands of brilliant scientists are going to stand together and tell the world that $ BILLIONS need to be spent to fix a problem that a “few Siberian treestumps” tells us about?
There is a tremendous amount of evidence that humans are warming the climate and that we are now dominating natural forcing mechanisms.
Click the link on my name and see what I have presented which is, to the best of my knowledge, a pretty fair summary of what these thousands of scientists are finding. I am just the messenger – I do not do any research. I have nothing to gain by taking this position and I never voted for Gore. In fact, I am a registered Independent. More importantly, I am a scientist that seeks to know what the heck is going on.
I obviously am an AGW supporter and I have a viewpoint that is quite different than most here at WUWT. I appreciate that WUWT allows me to post my dissenting comments and, to give props to WUWT and its posters, I have learned a great deal by their replies. This latest Yamal controversy which I think is “much ado about nothing” has led me to research proxy data and I am more knowledgeable now.
@ur momisugly Jeremy (14:34:11) :
I never said we should stop questioning data. I think when the data keeps looking the same perhaps we should start thinking that maybe it is accurate. The NASA example you give is comparing apples to oranges (or should I say Tang?)
@ur momisugly Jakers (15:47:43) :
Isn’t it just amazing that the entire field of climate change was resting on just 10 or 12 trees!
Even Steve McIntyre doesn’t believe this. The hockey stick does not discount the instrumental record which shows tremendous warming in the modern era, especially the last few decades. Trees or no trees.
————————————————-
A person at RC posted an interesting observation. CA, and subsequently WUWT, got into a tizzy because it appeared that only a subset of tree data was being used to reconstruct past climate. Posters at these two sites asked why not use ALL of the tree data instead of a subset?
Shouldn’t all of the data be better than a small subset?
Now let us think about surfacestations.org. The claim there (and often here) is that the full NOAA station record is contaminated by UHI and we should only use a SUBSET of validated rural stations. I think it was 70 out of 1221?
So is this cherry-picking (according to CA and WUWT) or is this just using the “best data” (Briffa) to get the correct reconstruction?
Touche’
“…based on the application of a tree-ring processing method applied to the same set of composite sub-fossil and living-tree ring-width measurements provided to me by Rashit Hantemirov and Stepan Shiyatov which forms the basis of a chronology they published (Hantemirov and Shiyatov 2002)”
This isn’t Adam blaming Eve, is it?
“My colleagues and I are working to develop methods that are capable of expressing robust evidence of climate changes using tree-ring data”
Was a grant given to you based on this premise? Is this why you are working to develop these methods?
Jeremy (14:58:25)
Well said, Jeremy.
Leif Svalgaard (09:14:03) :
does not look entirely flat to me
Ahh, but does it look like a Hockey Stick? That would be the issue at hand, wouldn’t it, sir? Maybe you weren’t aware of a graph called the Mann Hockey Stick.
Have you heard of a movie with a man named Al Gore in it called “An Inconvenient Truth”? That graph was featured in it.
Statisticians, scientists, economists, professors, politicians, and many other people from all walks of life have looked in to the issue of this ever so slightly important ingredient to the topic of global warming.
You may wish to take some time to brush up on the topic of global warming before commenting on it.
Or maybe I should lower my expectations of you and ask if you have ever heard of a thing called “GLOBAL WARMING”?
We all know this was cherry-picking, pure and simple.
And we all know that tree rings are not thermometres.
And we all know the team like them because of their cherry-picking potential.
And we all tired of having to pussy-foot around calling the kettle black.
You don’t think the climate ever changes, and he has to explain himself on that basis, he has to be ashamed of himself? He made no reference to AGW.
Bugs:
I see other problems with the Briffa quote. I don’t really think Briffa meant to say it, but by implication he is saying the previous methods were not capable of expressing evidence of climate changes in a robust manner.
This is fine as long as the summaries for those previous papers be changed to:
Now that this data is available any scientist, statistician, engineer, or mathemtician (etc) who is on the fence about global warming will have something to work with for themselves which will influence them one way or the other!
Thank you Mr. McIntyre. And thanks to the Royal Society for the pressure!
Scott A. Mandia (18:12:27) :
The hockey stick does not discount the instrumental record which shows tremendous warming in the modern era, especially the last few decades. Trees or no trees.
0.23C over the past 3 decades
http://www.drroyspencer.com/wp-content/uploads/UAH_LT_1979_thru_Aug_091.jpg
is that tremendous warming? it’s only .7666/century which is the same as the 20th century.
Mandia:
Nobody is saying to use a subset.
The whole point is to demonstrate that the record, as it stands, is completely contaminated and essentially useless.
See, unlike SOME people, the vast majority of “skeptics” actually understand how Science works. The correct course of action would really be to discard all past temperature records (which ARE unreliable, no sane individual can possibly argue otherwise) and BEGIN AGAIN.
And, while beginning again, throw out the ridiculously applied concept of a “precautionary principle” as CAGW proponents want to see it applied.
While they’re at it, the CAGW proponents could learn some reading comprehension, and stop hanging out at a corporate sponsored, highly edited “blog” for their information.
“Ecotretas (10:24:00) :
It’s interesting to see the grants Briffa’s involved in:
£106,423: ECOCHANGE- Challenges in assessing and forecasting biodivesity and ecosystem changes in Europe
£125,000: Climate Change – Fellow 1 -modelling of the Earth’s climate
£123,789: Process-based methods in the interpretation of tree-growth/ climate relationships
£121,880: To What Extent Was The Little Ice Age A Result Of A Change In The Thermohaline Circulation?
£226,981: Quantitative applications of high resolution late Holocene proxy data sets: estimating climate sensitivity and thermohaline circulation influences
£3,732: Statistical callibration of Eurasian tree ring records.
£1,000: ARC (Academic Research Collaboration) :Long tree ring chronologies in the Alps.
Taken from http://go2.wordpress.com/?id=725X1342&site=wattsupwiththat.wordpress.com&url=http%3A%2F%2Fwww.cru.uea.ac.uk%2Fcru%2Fresearch%2Fgrants.htm
Grabbed a copy, just in case.
Ecotretas”
Interesting, that’s a lot of bling! Also, the earliest grant starts in 2003, he’s been granted for many years, must be a wealthy, and all of a sudden healthy, man by now. Glad to see where some of my tax pounds went…down the drain it seems.