In China, there are no hockey sticks

Fourier analysis on time series may be a lot of fun but until physical background of identified cycles is demonstrated it’s not more than just playing with numbers with zero predictive potential.

sombody should tell our so called australian prime minister about no hockey sticks. the goose has her head in the sand

Oh and the manufacture Solar and wind turbines. They haven’t come out to say there will be no warming or cooling, just in case. They picked a high altitude country too. Nevertheless, they have agreed on one point, it ain’t unusual….IF temps fall suddenly in the Northern Hemisphere that will be telling. Look as a kid in UK, both north and south, it was always cold and raining. We didn’t always have snow at Christmas time, but certainly Jan and Feb, even as late as Easter.
And for the next chapter, see what the other think of it.

Tree rings also show growth can be effected by drought or lack of rain, sunshine, etc.

Tree rings also show growth can be affected by drought or lack of rain, sunshine, etc.

True but there are ways of mitigating that. For example, select trees that live in areas that generally get very little / no rain at all during their growing season or trees that generally get way more than enough rain. Edge of treeline trees at high altitude work well because they don’t get a lot of rain anyway, most of their water is from snow melt, the trees are not close together and don’t shade each other, and temperature appears to be the primary growth limiting factor. Though they do stupid things like core strip bark bristlecones sometimes.
I don’t favor trees as temperature proxies because at best they only proxy for 2 (sometimes 3) out of the 12 months of the year.

M.A.Vukcevic says:
December 7, 2011 at 11:33 pm

I noticed when you posted on this last week that your analysis only looked for components with a period of 100 years or less. I remember noticing at the time that there seemed to be a component somewhat longer than 700 years and this analysis out of China finds an 800 year component. I asked in that thread if the 100 years was a limitation of your analysis software but maybe you answered me after I stopped following the thread or thought it was a nonsensical question given the length of the CET series.

Kasuha: “Fourier analysis on time series may be a lot of fun but until physical background of identified cycles is demonstrated it’s not more than just playing with numbers with zero predictive potential.”
It is more than just fun, Kasuha. The fourier analysis is done to show the dominant frequencies in the time series. That is a clue for where to look with regard to what is causing those dominant freqencies.
The hypothesis is that CO2 is a dominant driver of climate. This study provides a test for that hypothesis, as the CO2-driver is already in the timeseries. All we have done is increase the amount of CO2 and if it is dominant we should see it in the near future. Just by looking at the graph one sees that a rapid rise of temperature has always been followed by an immediate rapid decline of the same magnitude. I think that should give pause to all of us, really. If that is where we are heading, I’m off to buy some more coats.

Why have the Chinese decided to issue this particular set of lies at this particular time?

“The regularity of 600-year temperature increases and 600-year decreases (Figure 3) suggest that the temperature will continue to increase for another 200 years, since it has only been about 400 years since the LIA.”
Is this part: “about 400 years since the Little Ice Age” a typo?

You can check out who the authors ( LIU Yu, CAI QiuFang, SONG HuiMing,
AN ZhiSheng, Hans W. LINDERHOLM ) for:

Amplitudes, rates, periodicities and causes of temperature variations in the past 2485 years and future trends over the central-eastern Tibetan Plateau

are and their status in the academic/scientific world, together with some of the
citations they have in hand at:
http://csb.scichina.com:8080/kxtbe/EN/abstract/abstract504775.shtml
Not only was the study peer reviewed, but they did some of
field work too !

i’d love to know what mcintyre and jeff id think about that reconstruction. guess they would debunk it.

bushbunny says:
December 7, 2011 at 11:07 pm
////////////////////////////////////////////////////////////////
This report may influence chinese scientists and their political leaders. Reports such as this may be seen by the Chinese as a good reason not to get too concerned about AGW, and not to sign up to any world agreement unless it favours Chinese interests, ie., they get a dollop of cash, free industrial technology or otherwise assists in shifting the industrial power base their way from West to East resulting in their increased ecconomic might.
Whilst I welcome this study and whilst the resultant past temperature trends seem to fit in with what we know about history, before one crows too much it is important to bear in mind that this is based upon proxy reconstructions. Proxies are at best a rough and ready indicator of a ball park figure, and tree proxies in particular are poor proxies for temperature. Ring size reflects the then prevailing growing conditions and as Bushbunny states there are numerous factors (in fact many more than listed by bushbunny) that influence prevailing growing conditions.

There’s this, too:
http://www.arctic-frontiers.com/index.php?option=com_docman&task=doc_download&gid=242&Itemid=155
So we can probably say that the 60-ish year cycle is NAO/PDO
What is interesting in all of this (and now we get our tin foil hats) is if maybe some of these people knew this was coming. I mean, running paleo climate data through a spectrum analysis would be something one would think would have been done in the 1960’s. I wonder if they knew these cycles were going to peak at about this time and knew it was a great time to become rich and famous. Particularly Hansen. He was running around in the 70s telling people we were headed for an ice age if we didn’t stop burning coal. Then he changed to we are going to boil.
I wonder if this also adds to their sense of urgency and there apparent desperation in trying to get major regulations passed now. The rhetoric certainly has become shrill. I wonder if they realize that they have actually already run out of time.

Matt says:
December 7, 2011 at 11:48 pm
Does Bull stand for bulletin or bullshit? – I mean, where’s the magic word? Is it peer reviewed, is this a respected publication outside China? You were furious about Muller, obviously, because you didn’t like the conclusion. And now? Obviously, this time you like the conclusion – but what about peer review?
Is this this Matt?

Who cares about the climate, not NGO’s its about MONEY, always was, always will be. We have got to keep trying to stop them getting our cash for a false prophet (profit) sarc.

Finally! Tree rings you can believe in!
Do Chinese tree rings track local temps (unlike Russian ones)?

bill says:
December 8, 2011 at 12:05 am
Why have the Chinese decided to issue this particular set of lies at this particular time?
What sort of comment is this? Demonstrate to me that the “Chinese” angle has anything to do with it. “Issue” detracts from the fact that it was published. “Particular set of lies” implies they, the Chinese, have a whole set of lies. The term “set of lies” implies there are at least several lies being presented at this time. The word “lies” is a very provocative and serious and requires demonstrable proof that the what is being said is knowingly untrue. I’m waiting to hear why you are calling the Chinese multiple liars….Please explain.

Pete Miller~ Funny you should mention mann. Regarding what we have heard about just inputting Noise into his model, I have to wonder: would the Chinese data, plugged into mann’s model, generate a hockey stick?

Well it’s interesting; but I would quibble with their figure #3.
Their Stage IV straight line fit, seems reasonable, and it magically has the same magnitude slope as the three previous stages, but clearly the I, II, and III straight lines are really lousy fits to the data.
I do agree that the up down pattern is there, but they exaggerate the slopes in the first three to try and fool us into believing that the era since 1600 is just the same as earlier times, which it clearly isn’t.
But I agree with their general conclusion; the whole thing is a ho-hum so what ! And 2485 years of tree rings is a bit better than one yamal stunted weed tree.

Those who question the validity of this research because of the absence of a cause are missing the point. If one accepts that the data is real then the predictability of temperature fluctuations is startling irrespective of whether we know why it is happening.
They have taken a 1200 year period to identify the main frequencies and generate the Fourier coefficients. They have then applied these coefficients to generate a prediction for a completely different period spanning the years 835 to 1980. One only has to look at the correlation between actual and prediction to see that the match up is just astonishing.
My conclusion is that they are either right or they have manipulated the data in some way. I cannot really see that there is room for any other conclusion. My personal view is that they are right given that they have published the data necessary to allow other scientists to look for the same power spectrum and test their conclusions. They would not have done this unless they were confident. Mann et al please note.

bill at 12:03 am above:
Bill,
The journal date for the publication of the Liu, et al 2011 , sumaary was
October 2011.
If I’m reading the material correctly at:
http://csb.scichina.com:8080/kxtbe/EN/abstract/abstract504775.shtmlt
[Please be patient, this was very slow downloading for me numerous times.
A traceroute showed the problem was with the servers at the far end (Asia)
of which several were running slow.]
the main study was originally submitted in March of 2011 and revised in August.
The study went through an unhurried peer review and editorial process
prior to publication in October.
This was published long before the COP17 delegates were gathering… and Jo Nova
brought it to our collective attention just now in December.

Great feeling for an author, who, with physics, for everybody transparent and understandable, calculated the 800 year (to be precise: the 790 year) cycle. Being validated with field reseach …great! See German Amazon.de : Book: ISBN 978-3-86805-604-4.
History proves the 800 year cycle wordwide, even in the most remote areas of the world (such asTibet etc) and with above quoted physical calculations, that they really exist…. well folks, sit back for a couple more years and the Hockey-stickers will be the laughing stock of history soon in this very decade…..
JS

The first figure actually does show Mann’s hockey stick for the last 1000 years. Which is the time period over which he made his annalysis. It does not show a MWP but does show a LIA.
Doesnt answer the question – are trees good thermometers?
The Fourier analysis is very interesting and Iwould love to see links there to other cycles

Bloke down the pub says:
December 8, 2011 at 3:34 am
“Statistics isn’t my strong point, but in figure 1 the bottom SD curve doesn’t look right.”
Mine either. And actually, both sides of the SD curve look wrong. Shouldn’t the SD curves be equidistant from the mean? Unless they did it from the mean of the whole series rather than each data point.(Though I’m not sure I’ve ever seen it done that way) Maybe this isn’t a statistical analysis?

Liu Yu, Director of Earth Environment Institute of the Chinese Academy of Sciences, was interviewed about his paper by the South China Morning Post (Dec 4, 2011):
Where did you find trees more than 2,000 years old in a country with a long history of systematic logging? I need luck to find a tree more than 100 years old in the lowlands. But on some mountains of the Tibetan Plateau, where the altitude reaches up to 4,000 metres, I have run into forest after forest of Qilian junipers that have remained undisturbed for thousands of years.
How does a tree survive in that kind of harsh environment for so long? The Qilian juniper is one of the oldest surviving tree species on earth. In the high altitude of the eastern Tibetan Plateau, where poor soil, little rainfall and low temperatures make it impossible for other trees to survive, the juniper has perfectly adapted to the harsh environment by growing very slowly. We recently found one that is close to 2,000 years old, but less than 8 metres tall. In the study of tree rings, slow-growing trees provide information on variations in climate over a long period. Qilian junipers grow only in China.
Is the study of tree rings popular in China? Chinese researchers have studied tree rings for more than seven decades, and some scientists have produced original studies containing a trove of important data on the climate. But due to historical reasons, their research methods did not quite fit with international mainstream thinking, and therefore not widely recognised. Since the 1990s, as climate change has become a political and diplomatic issue, the study of tree rings has received increased government funding, allowing Chinese researchers to use the best tools and methods and produce well-received results.
Are the field trips fun? To collect samples, we sometimes need to dance with death. At altitudes of more than 3,500 metres above sea level, my research team has to combat low air pressure, a lack of oxygen, headaches and sometimes life-threatening illnesses. The best Qilian junipers for our purposes often stand alone on a cliff, where they can be fully exposed to the elements. We have to watch our step when approaching such trees. Some researchers from overseas have slipped and died in less-perilous situations. Most virgin forests of Qilian junipers are in areas inaccessible by road, and are barely, if ever, visited by humans. The remoteness turned each of my more than 20 data-collection trips over the past 10 years into unforgettable adventures. Standing so high up, with an ancient tree, one has the opportunity to enjoy some of the most breathtaking landscapes on earth.
Do you need to cut down a tree to take samples No, we do not cut down trees. Once a tree is selected, we use a long, fine tube similar to a chopstick to bore through the trunk and reach the core. It’s standard practice used by scientists for a long time and does not cause the tree any serious damage. In the laboratory, all the samples must be polished with sandpaper. The work is time-consuming because the samples cannot be used for measurement until they are smooth enough that, when put under a microscope, we can see a perfect outline of their cells.
What do you do with the data? Using a set of scientific techniques, we measure the width of the rings and convert the variations into changes in annual temperatures. We have published two papers in the English versions of Science in China – Series D: Earth Sciences and in the Chinese Science Bulletin.
What have tree rings told us about climate change over the last two millennia? Popular belief is that industrialisation has led to the fastest rate of warming witnessed by humans; that we are at the warmest time of the modern era; and that we are causing global warming by emitting carbon dioxide into the atmosphere. None of that fits the records in tree rings. In northern China, the warmest period occurred from AD401-413, which had an annual mean temperature 0.16 degrees Celsius higher than today’s. Other periods, including 604-609, 864-882 and 965-994 had temperatures higher than in recent decades. Our results are supported by historical documents from the period. Archaeological records in Loulan , Xinjiang , show that pomegranate, a fruit rich in vitamin C, was used as currency during the Eastern Jin dynasty (AD317-420). The fruit could not possibly have appeared in northern China without a climate much warmer than today’s. And we are not experiencing the most dramatic climate change in recent history, either. Over the past 2,485 years, the biggest climate change took place during the Eastern Jin dynasty. The period had two stages, with the temperature plummeting first and then soaring. In the warming period, the mean temperature [in the Tibetan Plateau region] increased suddenly from 1.66 degrees to 2.67 degrees in 30 years. In the cooling period, the mean temperature dropped to below that of the Little Ice Age [an abnormally cold period that lasted from about 1550 to 1850]. The coldest years, with a mean temperature of 1.38 degrees, occurred from 362-369, and the temperature was about 1.5 degrees lower than the mean temperature of the late 20th century.
So what causes climate change? We believe that the sun and atmospheric circulations play a vital, if not decisive, role in this. The millennial cycle of solar activity determines the long-term trends of temperature variations. Almost all sunspot minimums [periods of sometimes several decades when sunspots become rare] correspond with low-temperature intervals. Meanwhile, atmospheric circulations affect temperature changes from decade to decade. To quote Professor Zhu Kezhen , the father of climate change studies in China: “The big changes in the earth’s climate have been controlled by solar radiation, but the small changes by atmospheric circulation.”
Can tree-ring records tell us anything about the future? Our results show that the temperature continued to increase until 2006, and will now decrease until about 2068. After 2068, the temperature will increase again until 2088.
Do you think your research will help Beijing gain ground in climate negotiations? I am a scientist, and I know nothing about politics. But the climate- change debate, in my opinion, has more political significance than scientific. Diplomats can sit at negotiating tables talking about carbon caps while scientists have not reached an agreement on the role of carbon dioxide in global warming. But political decisions must be based on sound scientific foundation, or they will be useless, if not dangerous.
http://www.scmp.com/portal/site/SCMP/menuitem.2af62ecb329d3d7733492d9253a0a0a0/?vgnextoid=8ef931369d404310VgnVCM100000360a0a0aRCRD&ss=china&s=news

Good on the Chinese – sure.
How embarassed will we in `the free West’ be if it turns out that science in an authoritarian, communist state manages to turn out objective and correct analysis whilw efounder with politicised, agenda riddled rubbish.
Where is the self respect of our once great scientific establishment.For how long are natural scientists in the West going to sit on their asses and not speak out against this disgraceful stacked deck, that `climate science’ has become?
Disclosure: The Bear’s wife is Chinese. Guess that makes the Bear in the pay of evil sceptics, eh?

matt a~ I have looked at all of the graphs very carefully. I see massive ups and downs, where do you see a long, flat line?
Dare I ask what the ‘a’ stands for your name? I would guess it stands for [self-snipped]

Observer – thanks for that interview….. It had all sorts of wry comments re: ‘mainstream’ thought and ‘politics’ and importance of their own work. A Mann smackdown! Ha ha ha! ;-D

Tree rings are still poor proxies for climate. Too many variables leading to soft conclusions.
I would rather concentrate on the more important subject matter: who is funding the NGO’s and what is their agenda.

Liu Yu,
Director of Earth Environment Institute of the Chinese Academy of Sciences,
Would you be willing to take a student on board and show him a few `tricks` on how to do tree ring research ?,
his name is Mike Mann, he currently lives in America and would probably love to do a bit of travelling right now.

“What these results show is that there are cycles in the climate between good growth conditions and poor growth conditions for that species of tree in Tibet. “…
…and with some average synchronicity with similar good and poor conditions that affected trees elsewhere in the world, and that are also correlated with some other proxies or historical accounts of temperature.
Don’t forget Bayes. Data like this doesn’t stand alone — it is linked by Bayes to other datasets.
rgb

The Institute of Earth Environment Chinese Academy of Sciences (IEECAS) was established in Xi’an in 1999, it is based on the Stay Key Laboratory of Loess and Quaternary Geology, CAS, which was founded through the efforts of Prof. Liu Tunghseng, An Zhisheng and others in 1985. http://english.ieexa.cas.cn/
Jono – For information of CAS Earth Environment Institute on management of post-doctorate, such as application procedures, application form and application, etc, please contact Zhang Yingwen at zyw@loess.llqg.ac.cn.
Matt – Liu Yu, male, born in 1963, doctor, research fellow, doctor tutor and Director of Earth Environment Institute, CAS; winner of National Fund for Outstanding Youth and the State Council’s special allowance for experts with outstanding contributions. Mainly in climatologic research of tree ring; published more than 70 Chinese and English papers; his research results of tree-ring stable isotope were appraised as the “Curve most reliable in Asia and favorably comparable with tree ring isotope results from other three major continents in the world” by international authoritative experts in the field; he chaired more than 20 topics, including Class II topic of major topic under National Fund Committee, key topic, outstanding youth fund and Class II topics under 973 Program of the Ministry of Science & Technology, etc. He also keeps close international cooperation with Sweden, US, Germany, Russia and Korea, etc. He chairs the Institute in all aspects, with specific duties on Party affairs, education, supervision and audit.

Um, i don’t know, I think I still see a hockey stick at the end there …Just a little bit of a hockey stick….I think so… at the end there… see it?..Its there I’m pretty sure…

JThoms says:
December 8, 2011 at 4:48 am
Wow… Just Wow!!
“NotTheAussiePhilM says: December 8, 2011 at 1:50 am
Finally! Tree rings you can believe in!
Do Chinese tree rings track local temps (unlike Russian ones)?”
What a statement – boils down to: I believe that data – is that data valid !!!!!! all in a couple of lines!
Magically treemometers are accurate in China but just garbage when in Russia.
Wow.. Just Wow!
====================================================
Can I presume that you have no idea as to what the issue is with Russian temperature collection?

Thanks Observer, that interview was gold. The original post is interesting too of course.
I still think I’d take tree-rings over ice-cores as proxies, sure they are proxies, but if we had actual temperature measurements for the last 2000 years I reckon someone should be publishing them…
As for being just curve-fitting (and it does look pretty good curve fitting). 1. It raises real questions about the effect of CO2 as a ‘driver’ of tibetan climate because the current warming over the time series is not unprecedented whereas the current CO2 apparently is. 2. If the curve fitting identifies cycles and a plausible physical mechanism exists for those cycles, you then have a predictive, and hence falsifiable hypothesis.
As for lack of known short cycles, they’d be hard to pick up in a slow-growing, long-lived tree is my guess (you can have short, hi-res, or long low-res).

I’m pleased to see others using a wave analysis technique on proxie data similar to what I have been doing. Even more so in that their results are also similar. Take a look at my plot of SST anomalies based on ice core data. http://www.kidswincom.net/climate.pdf.

@ Peter Plail “whatever else tree rings show, they are a good proxy for human well-being.”
Good point! Very good point.
@ crosspatch and eyesonu “That they were well aware of the 60 year cycle and pushed so hard for regulations and now that time has run out would fully explain the last ditch effort we are seeing now. ”
Yeah, that has been my suspicion as well. The push for CAGW has been so well coordinated, so well funded, so well supported by the media, and such a good investment for those who desire more money and power — at some point collusion and planning becomes the simplest and most reasonable explanation.

I cannot support the conclusions until I see the original data, the methodology used, the assumptions made and can replicate the results.
I am old enough to realise that I can be fooled easily, especially by results which appear to confirm substantially my own beliefs.

There has just GOT to be better thermometers out there than tree rings.

“I am a scientist, and I know nothing about politics. But the climate- change debate, in my opinion, has more political significance than scientific. Diplomats can sit at negotiating tables talking about carbon caps while scientists have not reached an agreement on the role of carbon dioxide in global warming. But political decisions must be based on sound scientific foundation, or they will be useless, if not dangerous.”
Yup. That does sound like a scientist.
Certainly doesn’t sound remotely like Meltdown Mann.

Robert Brown says: “To which I would add that the FT of a 2400 timeseries is going to be dominated by modes with period 2400, 1200, 800, 600, 400… very nearly a priori — you’d have to have a rather special curve (one orthogonal to these modes by construction) in order for this NOT to be so.”
FT would be useless if all it did was “find” subdivisions of the sample length. And the sample length is 2485, not 2400, and the full-length ‘cycle’ is definitely absent. It does contain cycles of 50, 37, and 30 years. Yes, chaotically trending (i.e. not white noise) data will generate false cycles that cease to maintain into the future – hence your stock market remark. The question is then, are these cycles false or are they real cycles being detected? If climate is a combination of both cyclic (e.g. PDO) and non-cyclic (e.g. volcano eruptions) events, then we might expect some of these cycles to be robust to a reanalysis of subsections of the data, whilst others should destabilise. In any event, your warning about the possibility of (but not the necessity of) artifacts is correct, and some of these cycles almost must be artifacts for physical reasons (the existence of non-periodic climate influences). I doubt that the prediction will come true to any degree of precision, although there are other physical reasons to expect some cooling.

“Now some will argue that skeptics scoff at tree rings, and we do — sometimes — especially ones based on the wrong kind of tree (like the bristlecone) or ones based on small samples (like Yamal), ones with abberant statistical tricks that produce the same curve regardless of the data, and especially ones that truncate data because it doesn’t agree with thermometers placed near airconditioner outlets and in carparks. Only time will tell if this analysis has nailed it, but, yes, it is worthy of our attention.”
Skeptics would be foolish indeed if they bought the simple minded claim that measuring tree ring width, or any other proxy, can tell us what temperatures have been for thousands of years. The reason is that proxy work has been non-empirical. No one does empirical study on the proxy item to determine how it changes under various environmental conditions. What must be done if proxies are to be used is that experiments must be conducted on individual proxies to determine their rate of change as various important elements of their environment changes. Anything less is non-empirical. Anything less is whistling by the graveyard. Briffa whistled by the graveyard and when his tree rings diverged from what he expected he was left entirely flat footed not knowing what had caused the divergence. Surely, this trap for the non-empirical scientist is clear as crystal and need not be debated again.
Non-empirical proxy studies invite confirmation bias. Some climate scientists justify their claim that their proxies measure only temperature by selecting trees at the treeline of mountains. Then they say that the other variables have been minimized so only temperature is a variable and their study is objective. Is it not obvious that what they have done in fact is select proxies that maximize the impact on the study of the variable that they had predetermined to be most important, temperature, and minimized all other variables. That is confirmation bias writ large.

Peter Plail says:
December 8, 2011 at 1:36 am
“Whether or not tree rings are a good proxy for temperature, they are a precise indicator of conditions which are beneficial for tree growth. From this it would not be difficult to conclude that those conditions have a similar impact on other plant growth, including food crop yields.”
Only one is needed. Human management is incredibly beneficial for tree growth and it can be effective even when the climate has turned sour for plant growth in general.

JJThoms says:
December 8, 2011 at 4:48 am
Do Chinese tree rings track local temps (unlike Russian ones)?”
What a statement – boils down to: I believe that data – is that data valid !!!!!! all in a couple of lines!
Magically treemometers are accurate in China but just garbage when in Russia.
Wow.. Just Wow!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
and Observer says: (Quoting an interview…..)
Can tree-ring records tell us anything about the future? Our results show that the temperature continued to increase until 2006, and will now decrease until about 2068. After 2068, the temperature will increase again until 2088.
======================================================
JJ is correct. I take little comfort in treemometers that kinda sorta tell us what we already knew. In our zeal to believe this treemometer reading extraordinaire, someone should actually check the veracity of his statement. Now, I haven’t looked at local Tibetian temps, so maybe that’s what he’s referring towards in his oddly specific prediction/backcast. 2007 was warmer than 2006…… 2010 treemometer data was probably not available…..so, there’s that….
Can anyone tell me how we come to a reasonable assumption of what the low temps were while looking at the tree rings? Is there a negative ring growth which I’m not aware of? You see, when determining a mean like this, you need at least two numbers…. a high value AND A LOW! How does a tree ring determine the difference between 0°F and -40°F? It’s nothing but WAG. And we’re suppose to believe it was precisely 54.3° precisely 720 years ago. Whatever……

OB-I think SM and JI would apply the same intellectual rigour to this paper that is extended in all of their endeavours. If you don’t think they are motivated by scientific curiosity and honest intention to extend knowledge then you haven’t not been reading much. If this paper is crap, they will say so.

This would explain why my kid’s hockey team beat a Chinese team pretty soundly last summer at a Huntington Beach tournament.

Kasuha says:
December 7, 2011 at 10:51 pm
Fourier analysis on time series may be a lot of fun but until physical background of identified cycles is demonstrated it’s not more than just playing with numbers with zero predictive potential.

I agree that Fourier Analysis can be quite misleading when you are dealing with something other than a continuous signal. Having said that, their highest amplitude signal has a period of 110 years. It repeats 22 times in the 2500 year window. The second highest amplitude signal is 199 years which repeats 12 times in the window. They probably aren’t spurious.

Kasuha says: Kasuha says: December 7, 2011 at 10:51 pm
“Fourier analysis on time series may be a lot of fun but until physical background of identified cycles is demonstrated it’s not more than just playing with numbers with zero predictive potential.”
Fourier Analysis is but one of many tools, that attempt to understand complex systems & predict future directions. The climate system has yet to be completely understood, and use of different tools aid to that understanding.
Below is a comparison between Fourier & Empirical Mode Decomposition filtering, using the CRU data. Note there seems to be very good comparison in the results, by two very different mathematical.methods.
http://www.4shared.com/photo/2foIw4k7/CRU-Fig-6a.html
However it might be worthwhile to look at Signal Conditioning literature. The IEEE has a designated Group relating to that area. Or you can pick up a copy of “Measurement of the Power Spectra”, Blackman & Tukey, for a basic understanding of the Fourier methods, and Applications.
A side note, was that Drs. Norbert Wiener & Charles Draper worked together, using Fourier methods, to develop the Navy MK 14 gun sight during WWII. This later morphed into a A/C gun sight (B-29, F-86)..
As far as use of Fourier methods in the stock market, check out the TradeStation package, for starters.
.

I’m sure that the Team will roll out a “peer-reviewed” study in a few weeks attempting to refute this study. It seems to me that the only way they can try to refute this is to question the accuracy of “treemometers” which will cast doubt on the Mannian hockey stick. The Team’s other alternative is to ignore it. I can’t wait to see what they do (or don’t do).

I’m only a highly interested civilian when it comes to the study of global climate. But, it has always seems logical that cycles within cycles would dictate global climate. Starting with the sun and then adding things like the “Chandler wobble.”
Is there any research into the length of the cycle of the migration on magnetic north? This appears (to me) to be the best measure of the earth’s wobble.
http://en.wikipedia.org/wiki/File:NASA_54556main_nmppath2001_med.gif
Magnetic north was fairly stable for decades (centuries?) at it southern extreme and now is moving quickly toward Siberia. Will it reach a southern extreme and stay there for decade or centuries?
Could this be the 1324 cycle? The NH/world warmer when magnetic north is in Canada and colder when it is in Siberia? With relatively quick transitions in between the two cycles….
I wish I had the proper training to tackle this project myself…all I have is a hypothesis.

The second paper Liu Yu referred to is:
Annual temperatures during the last 2485 years in the mid-eastern Tibetan Plateau inferred from tree rings
LIU Yu, AN ZhiSheng, Hans W. LINDERHOLM, CHEN DeLiang, SONG HuiMin, CAI QiuFang, SUN JunYan & TIAN Hua
Science in China Series D: Earth Sciences
Received July 25, 2008; accepted December 22, 2008; published online February 3, 2009
http://cadata.cams.cma.gov.cn/nianlun/upfile/China%20Science.pdf
Supported by National Natural Science Foundation of China (Grant Nos. 40525004, 40599420, 40890051), National Basic Research Program of China (Grant Nos. 2007BAC30B00, 2004CB720200, 2006CB400503) and the Swedish International Development Cooperation Agency (SIDA, Grant to Hans W. Linderholm).

I have to agree with Matt … if this study showed an unusual warming in the 20th Century this blog would be tearing the paper to shreds lol

It’s interesting how well this matches what we know from historical records from Europe. I especially noted the very steep drop from ca 1550 to 1600. The 16th century was very warm in its first half, with some of the warmest summers ever in Europe, but the climate cooled dramatically in the second half of that century.

nomnom says:
December 8, 2011 at 8:55 am
Started at 900ad, ended around 1350ad. Just as the graph you posted says. Before and after. See? Or were making a joke?

nomnom says:
December 8, 2011 at 8:55 am
So this Tibet record shows the “MWP” happened before 1000AD
Yet the Central England Temperature record derived graph shows the MWP happened after 1000AD
http://andyrussell.files.wordpress.com/2010/05/ipcc_far_1000.png
Explain that one skeptics.

The Medieval Warm Period is portrayed differently depending on what proxy you are looking at. Liu’s graph shows a sharp peak just before the year 1000. It is similar in that respect to the graph produced by: Esper, E.R. Cook, and F.H. Schweingruber (2002). “Low-Frequency Signals in Long Tree-Ring Chronologies for Reconstructing Past Temperature Variability”. Science 295 (5563): 2250-2253.
There are lots of proxies. They don’t agree very well. Don’t get your shirt in a knot by trying to read too much into them. Historical evidence and proxies tell us that there probably was a Medieval Warm Period. It may have been warmer than it is now. That’s all we can say with much confidence.
http://en.wikipedia.org/wiki/Medieval_Warm_Period
http://en.wikipedia.org/wiki/File:2000_Year_Temperature_Comparison.png
p.s. I was a warmist until Mann tried to erase the MWP; that made me sit up and pay attention to the science.

Do we have all code and all data – used and not used – for this?

For everyone who see the HS in the first graph, here is the HS overlaid on Liu et al’s graph:
http://i40.tinypic.com/35c4bw9.jpg
Mann lacks 50-70% of variation in his reconstructions that Liu, Loehle and Moberg all seem to find. Is it not interesting what the HS would have looked like if it started only 50 years prior=FAIL.
Loehle with HS: http://i39.tinypic.com/2q3arlw.jpg
Loehle and Moberg: http://i46.tinypic.com/2lcvct1.jpg

This is scary. Feeding 6 billion people requires warmer, wetter weather with lots of CO2.
Just look at the graphs and compare the dates of the cool periods and the warm periods with economic boom and bust periods of the past.
If you want to read more, try Climate, History and the Modern World by H.H. Lamb. 2nd Ed. I have both 1st and 2nd.
During the cooling around the mid-1970s, Lamb thought an ice-age might be coming but in the 1990s decided that the Earth would continue warming. So he is no more reliable than anyone else about the future.
But about the impact of climates of the past he was a world class expert and well worth the read. The book sells for a ridiculous price on Amazon, but libraries can order it on inter-library loan.
To give you an inkling: Lamb describes the hardship caused by the Little Ice Age in Europe. Iceland was completely ice-bound for 2 years making it impossible to get the fish people needed to survive.

This will either be a resounding blow to AGW or “Chinagate”. We’ll see as the dust clears. This paper will be beaten to a pulp or become an icon or both.

The science is unsettled (ing).

Pardon me for being very direct, but something very important about statistics needs to be understood by all. You cannot go out and collect measurements of whatever, fail to do the empirical work that shows that the individual measurements are sound, then expect your statistical work to make up for the empirical work that you did not do. The principle is parallel to GIGO. I recommend calling the principle “NEINO” for “non-empirical in non-empirical out.”

nomnom says:
December 8, 2011 at 8:55 am
So this Tibet record shows the “MWP” happened before 1000AD
Yet the Central England Temperature record derived graph shows the MWP happened after 1000AD
http://andyrussell.files.wordpress.com/2010/05/ipcc_far_1000.png
Explain that one skeptics.

Tree rings measure only June/July temperatures. Maybe THOSE peaked in THAT location earlier. A tree ring series in one region can not give a signal for GLOBAL climate, only the climate in that location and only for June and July. There is still room for regional variation due to changes in storm track, etc. Also it could be there was a rainfall anomaly prior to 1000. One thing I have learned is that the ITCZ and monsoon rains tend to also track with the LIA (and MWP). So it could well be that they got increased precipitation in that location before the MWP temperatures peaked. But the fact remains that the SAME signal(s) in those data appear in other data as well.

crosspatch says” “Tree rings measure only June/July temperatures. Maybe THOSE peaked in THAT location earlier”
What if the two periods simply weren’t warm at the same time? Ie no global medieval warm period.

crosspatch says:
December 8, 2011 at 11:10 am
……..
Tree rings measure only June/July temperatures. …….
Tree rings do not ‘only measure temperatures’.
All tree rings show is the growth rate of the tree over that year. Provide water, nutrients, sun and a slightly cooler temperature – and you get a nice fat tree ring. Provide drought, low nutrients, obscured sun and hot temperatures – and you get an emaciated tree ring.
A challenge – run the validation experiment I proposed above (http://wattsupwiththat.com/2011/12/07/in-china-there-are-no-hockey-sticks/#comment-822884 ) show that it is possible to quantify the annual average temperatures accurate to 1 degC using tree rings using a double blind protocol. If the experiment shows that it is not possible to quantify temperatures from tree rings, then all papers using tree rings as proxies for temperatures should be withdrawn.
This is what scientists and engineers would do.

“Explain that one skeptics”.
But the best thing about climate science is, you don’t have to explain anything!
Cherry picking is also legitimate. Hockey Stick or Tibet, have to think about that one. I asked Ted, our Tibetan terrier, but he went for option 3, the sausage.
If they release their data and source code perhaps that will encourage Phil to have another look on his desk.

This analysis was also done with the temperature record from the UK (CET) with the same results. It is not just tree ring data that shows these cycles. See the link early in the comments.

Vukcevic,
Doesn’t look like it to me:
http://img709.imageshack.us/img709/4205/loehle3.jpg

And we can point to the temperature response since 2000 to show that the analysis apparently does have some predictive pattern. The tree ring survey does not contain data for those years yet the resulting waveform accurately depicts what we see in actual observations. In other words, unlike the now-discredited hockey stick hypothesis, this output is validated by actual observational data.

nomnom,
Your chart shows global temperature going up a full degree Centigrade in a short time. Where did that chart come from?

M.A.Vukcevic says:
December 8, 2011 at 11:52 am

I have a suggestion for an experiment.
Run your analysis on CET only to 1990. Now plot the composite wave and continue it past 1990. Now plot on that composite only temperatures AFTER 1990 which were not part of the analysis. That should give some idea of any predictive skill. Now do the same for another record. I suggested the Blue Hill Observatory as it is the longest continuous record and it was done by skilled observers. It would be the record I would put most trust in for accuracy in the US.
Another note about these cycles: depending on what their activation mechanism is, they could show different (or opposite) response depending on their location. Lets imagine there was some correlation with Markowitz Wobble (a roughly 30 year cycle). This would be expected to show up most strongly in records the farther North one goes as it would potentially have more impact on insolation in the North than in the tropics. So the relative strength of the various signals can vary according to region of the planet. If there is movement of weather patterns such as the ITCZ with the 800 year cycle, it might have a profound impact in one area and much less (or opposite) in another.
So the energy distribution among the various cycles found might be different in different regions (or even hemispheres) of the planet and the cycles could be out of phase between locations. This is one reason I do not favor creating ensemble sets where several data sources are added to create a composite. I would rather favor running the analysis on individual data sources and comparing the result. If you create an ensemble and attempt to run the composite signal of that ensemble through a “notch” filter to obtain, say, the 60 year cycle, maybe that doesn’t work if the signal is there but out of phase between members of the ensemble and they cancel. A slight shift of the monsoon can have a rather dramatic impact, particularly in mountainous areas with rather severe “rain shadows”. Growing conditions can suddenly vary considerably between two locations what are not separated by very much geographical distance and would be more of a topographical consequence of the change than anything else. So the same cycle may be there but out of phase. If I attempt to add the two data sets together, the signals might cancel to some extent and suppress the actual manifestation strength of the signal.

So, is this study going to be listed in the IPCC report? Or is it going to be “kept out somehow” even if means redefining what is peer-reviewed literature?

Does this data use thermometer data for the last hundred years, like Mann’s hockey stick, or did tey use tree ring data for the entire plot. If the latter, this study doesn’t suffer from the divergence problem, and may be a more accurate local temperature record.

The evidence in this paper is entirely consistent with the following post that I placed on another forum because it shows exactly the sort of pattern one would expect to see in a single region as the climate zones overhead shift latitudinally to and fro in the process of maintaining overall thermal equilibrium despite variations in forcing factors.
“Note that the ONLY effect of ALL factors capable of changing climate is to influence the rate of energy flow through the system. At any given moment all those factors are netted out to cause either slight warming or slight cooling.
The system can only respond to changes in the rate of energy flow through the troposphere in one way, namely the surface air pressure distribution which is intimately connected to the size and/or speed of the water cycle.
When the surface air pressure distribution changes significantly it does so by altering the relative sizes, intensities and average latitudinal positions of ALL the permanent climate zones.
If the net forcing effect of ALL variables is towards warming then the surface pressure redistribution acts to speed up the rate of energy flow through the system to maintain equilibrium by shifting everything towards the poles.
If the net forcing effect of ALL variables is towards cooling then the surface pressure redistribution acts to slow down the rate of energy flow through the system to maintain equilibrium by shifting everything towards the equator.
Once that is understood the only question to be determined is as to how far human CO2 emissions change the surface air pressure distribution as compared to sun and oceans.
Given the scale of the surface air pressure redistribution between MWP and LIA it cannot be much.
One can still debate the relative contribution of all the available variables so that is the next step.”

By the way, I love this comment over at CA:

The rule is: the MWP happened everywhere, so it was a local phenomenon. AGW is instead happening nowhere (in particular), so it’s a global phenomenon. Easy.

“So the relative strength of the various signals can vary according to region of the planet. If there is movement of weather patterns such as the ITCZ with the 800 year cycle, it might have a profound impact in one area and much less (or opposite) in another.
So the energy distribution among the various cycles found might be different in different regions (or even hemispheres) of the planet and the cycles could be out of phase between locations.”
Just so, and the main effect of a faster transmission of energy through the system from equator to space would be ‘excess’ warming at the poles just as we see now but in the Antarctic the effect would be much reduced because warm water cannot get under the ice and the continent is so large that warm winds don’t get to the centre though they do affect the West Antarctic Peninsula.
The global thermostat is actually a planetwide extension of Willis Eschenbach’s idea. It isn’t ‘just’ more convection in the tropics. It is actually the ability of the permanent climate zones covering the entire planet to shift latitudinally so as to provide the necessary negative response to ANY forcing so as to keep global temperatures within a relatively narrow range.
This paper is a picture of the process in action above one specific region.

crosspatch says:
December 8, 2011 at 11:47 am
So, you think tree ring width is a linear function of temperature? Please explain.

I’m suspecting that if you took the SST data and ran it through you are going to see the 60 year cycle as the dominant energy lobe and I would speculate that will be activated by the thermohaline circulation cycle.

So, you think tree ring width is a linear function of temperature? Please explain.

I do agree with Briffa that in certain locations, temperature is the primary growth constraint. This doesn’t hold in a global sense, only in very local conditions. The tree in my front yard is not a good temperature proxy. A tree near the edge of the boreal tree line might be. A tree that grows in an area that gets no rain during its growing season (so there is no variation in precipitation in June/July) in a mountain area near the high altitude tree line might also be.
In places where temperature is the overall constraint on annual growth, it may be a good proxy. But we can not say that a tree in such conditions NOW was always in such conditions. As I also said, things change. That same tree might have been under a persistent storm track 400 years ago. Giant Sequoia might be a better rainfall than temperature proxy, for example. A tree that has lived a very long time might alternate from being a rainfall proxy for some period of the record to being a temperature proxy. O18 analysis of the wood in each ring might be a better temperature signal than the width.
Generally, I don’t like trees being thermometers. If you find one that is, it is more luck than science. Traditionally trees have been used more as precipitation proxies than temperature.
But MOST importantly, this SAME sort of analysis has been run with actual temperature records and shows the same composite.
Also, for this case, it probably doesn’t matter if they are temperature or rainfall because the two often go hand in hand. You rarely see a significant multidecadal change in precipitation trend without it also being accompanied by a change in temperature. So bottom line is that overall growth conditions changed in a way that the graph depicts. Running a real temperature series (not a temperature PROXY), in this case CET, shows exactly the same cycles in play.
This is NOT a result unique to these trees.

would be ‘excess’ warming at the poles just as we see now

Can you give an example of this excess warming that we see now? I have been having trouble finding any. Southern Ocean sea surface temperatures seemed to have been trending flat from 1982 through 2007 but seem to have recently “stepped down” and appear to be establishing a new trend line about 0.2 degrees lower.
http://bobtisdale.files.wordpress.com/2011/12/13-southern.png
The Arctic Ocean is interesting in that it did trend upwards from 1997 to about 2005 but now appears to be reversing that trend.
http://bobtisdale.files.wordpress.com/2011/12/12-arc.png
At the same time, the temperature trend in the Indian Ocean appears to be the only ocean with an increasing trend. It was flat in trend from 1982 to 1996, rose from 1997 to 2002, trended down until 2008 and has had a significant uptrend since then.
http://bobtisdale.files.wordpress.com/2011/12/11-indian.png
Equatorial Pacific temperatures have been trending generally downward since the early 1980s:
http://bobtisdale.files.wordpress.com/2011/12/2-nino-monthly.png

nomnom says:
December 8, 2011 at 12:52 pm
Neither of those estimates match empirical observation, do they. You are entitled to your opinion, but you are not allowed to rewrite known history.

Anthony and Observer, thank you.
This goes into the evidence necessary for making decisions. I expect to see more records in the upcoming decade. It would be a mistake to give this data set and the resultant model too much or too little weight.
It will be interesting to see how close the observed tree ring widths are to the modeled tree ring widths in the future.

OK, forget about proxy reconstructions. This data shows the growth of these trees is rapid in the last few hundred years. It also shows they have grown at this rate or faster in the past. That by itself casts some serious doubt over the current warming trend being “unprecedented”.
That is assuming the data is not corrupted. That’s a pretty big nail in the AGW coffin all by itself.

The fundamental problem is that we do not have any good high-resolution temperature proxies in temperate regions that pre-date the thermometer. Every single one that I can think of would be “disturbed” by precipitation changes, flooding, etc. There are some fairly low resolution proxies but these aren’t good enough to “catch” things in the recent (Holocene) past that vary on annual or even decadal time scales. I would be interested in any speleothem research done in someplace like Mammoth Cave. I can find such work for the tropics in South America. The South American work seems to be another validating point showing the ITCZ greatly influencing rainfall and its general migration South in response to the decline of solar insolation decline in the Northern Hemisphere starting about 9000 years ago. What is most interesting to me is the sudden appearance of “noise” which they wonder is an ENSO signal that begins to appear only 4000 years ago. See figure 6 on the 126th page of this PDF thesis (page 104 of the document)
http://dare.ubvu.vu.nl/bitstream/1871/13246/5/8837.pdf
And I would also be interested in this paper if I can find it for free someplace:
http://geology.gsapubs.org/content/38/5/455.abstract
It looks like we can find some rather good data if it is located in exotic places to which someone might want to travel. We can’t seem to find anyone willing to travel to Kentucky to do it, though.

I see that “nomnom” is the nom du jour of the troll assigned to WUWT by The Team…
Well, OK, I’ll take a small bite out of the Troll Bait:
Dear NomNom, the globe does not ‘all go together as it goes’. It has time lags in some areas relative to others. It has oscillations that move in counterpoint. It has feedback loops and natural oscillations and teleconnections. Sometimes moving in opposite directions in different parts of the world.
Look up the AMO and the PDO and the ENSO. Learn about the way that the southern hemisphere often moves in opposition to the northern hemisphere in some time scales.
This is what is called “complex” behaviour. (As opposed to “the hobgoblin of small minds”, or a foolish consistency…)
So, you see, you can have a process that has onset in one place (like Europe) and takes a hundred years, or maybe even 200, to spread around the globe to other places.
I’ve frequently complained about the “over averaging” done to temperature data. (And been assaulted by the foolish for that statement). The simple fact is that averaging is done to HIDE things. (Often with very good results). I use a 25 day simple moving average to HIDE daily price movements in stock as they are largely news event driven. I want to see the longer term forces at work, not the daily noise. Hiding can be good… But sometimes hiding is bad.
In the case of global climate and weather cycles, averaging over the whole globe is bad. We know it is bad as we know there are longer cycle changes that affect different parts of the globe in opposition. (Yes, I really do want you to learn what the ENSO is and how the N vs S hemispheres have things that move in opposition). So averaging them together can HIDE what we want to FIND. Like the decline… (but I digress…)
Oh, and on the topic of cycles, I see that someone posted a link to Timo. He has a GREAT page on all the possible solar cycles. (I’m figuring folks can find it on their own…). There is also this interesting page that finds a lunar position driven cycle:
http://www.pnas.org/content/97/8/3814.full
Or, rather, many cycles. Plenty of real physical things that can drive the weather (even the long term weather cycles that warmers like to call climate, even though it isn’t…) on changes of durations up to 1800 and 5000 years.
Unfortunately for the warmers, things are kind of cold right now (and have been getting colder since we hit a peak in 1998 … you know last MILLENNIUM 😉
On the question of “did they know”: I suspect they did. Not only the Hansen synch change with the cold / warm 60 year cycle, but the way the “narrative” changes in sync with expectations just BEFORE those events ought to happen…
So we had “Global Warming” up to the late ’90s, then it morphed into “climate CHANGE” just as we hit the peak. Then just about the time the sun was about to go very sleepy, causing a UV plunge, shortening of the atmospheric height, and more violent winds – about like they were in the last similar event… Suddenly then we get “climate chaos” and stories of more wind related damage (hurricanes, tornadoes, ‘extreme events’) just a few years BEFORE they ought to happen from the shorter air column giving higher wind speeds (though of colder air…)
There is only so much “perfect accident” you can see before you start wondering where Remo is right now… (Google Remo Williams… 1985 or so, has Kate Mulgrew in it too)
So Occam’s Razor says the most simple explanation that accounts for all the known facts is that folks were seduced by power, believed in their own ability to pull off the dodge, and thought they were doing ‘the right thing’… but were wrong… THEN the schedule did not go as planed… Gang Agley as it were. They forgot that folks, especially the apathetic “rubes”, could take a Very Long Time to get on the band wagon. We had things building to a fever pitch in about 1985 – 1990… and The Folks didn’t quite notice… Took until about 2000 to really get on board. And by then they were behind schedule. Instead of a decade to show how The Solution Had Worked!, the were past the inflection point and into damage control… Time for “Climate Chaos”…
So now they are doing the last ditch histrionic SCREAM!!!!
And the rest of us are doing a “What? You overactor!” (in a Jim Carry kind of way:
http://youtu.be/eju7zSmHklA )
At any rate, we will now see, IMHO, a long drawn out process as folks both try to continue the effort ( This time for sure!) while trying to find ways to “distance themselves” from the inevitable fiasco as things go obviously cold. Very Cold…
BTW, for folks wondering where I’d gone:
I got a job on the other side of the continent. Then came home, Then had two wisdom teeth removed… (Yes, nearly 60 and still teething…. it’s those slow genes from the Neanderthal side, I’m sure 😉 but, to quote Independence Day: I’m BaaAAAAK!!!
Yeah, back short a couple of teeth… but hey, I can always gum ’em to death 😉
Per the posting: I think the Chinese have always done careful detailed (and sometimes over complicated) work. Looks to me like they are still doing careful work…
Oh, and per things that make trees grow: In the Pacific NorthWest they found that much of the nitrogen and phosphorus that got to the pine forest came from Salmon caught by bears, then carted off into the forest where bears do what they do in the forest… (“Does a bear Shxx … in the forest?”) So to the drivers of Tree Rings one must add salmon run size and Bear Poo….
I’m willing to assume that bear poo is not a major factor in Tibet Junipers… but you have to watch out for it. Especially in places with a lot of salmon… Like maybe Yamal… (Mann, have you looked at the POO climate driver? Maybe that’s the cause of the decline… not enough bear pooing in the forest… I’m sure POO is involved some way or another in the results…)

JJThoms says:
Wow… Just Wow!!
I looked up ‘Irony’ on Wikipedia, and this is what it told me:
“Irony (from the Ancient Greek εἰρωνεία eirōneía, meaning dissimulation or feigned ignorance)[1] is a rhetorical device, literary technique, or situation in which there is a sharp incongruity or discordance that goes beyond the simple and evident intention of words or actions.”
Just so you know, for future reference etc

It would be nice if there was a bit of recognition of simple sampling criteria rules. Looking at Figure 2 for example, Nyquist theory dictates that to properly observe/capture a specific frequency, one needs to record at a rate of at least double that frequency, and that’s assuming that the sampling is not out of phase in any way (imagine measuring daily temperature fluctuations by measuring twice a day. The waveform looks completely different if you measure at noon and midnight than if you measure at 6 PM and 6 AM). Furthermore, most experts would say that you shouldn’t assign any value or statistical merit until you have a sampling frequency of at least 6 to 10 times greater than the frequency being observed. If you don’t observe these parameters, you run the risk of aliasing your data, which will show up in a noise power spectra as incorrect frequencies amplitudes and, if memory serves, incorrect frequencies, too, particularly in more complex spectra where multiple discrete frequencies contribute.
Given that tree rings give you a 1 year frequency, they really should be putting a huge caveat with everything to the right of 0.166 (1/6) or even 0.1 (1/10).
On the flip side, the frequencies at 1324 A^-1 and 800 A^-1 should be considered dubious as well because only two full cycles of the 1324 frequency were experienced and 3 cycles for 800.
I do think a document like this is a very good step in the right direction (in contrast to the material put out by Mann, etc.), but the measurement science still has a very long way to go before the data is “tight” enough to merit the claims that many want to make about AGW. I suspect it will never get there w/o an enormous involvement from individuals expert in the measurement sciences.
I’d also say that I think a natural data set is infinitely more complex and less prone to high precision than a simple physical science calibration (perhaps calibration of a thermocouple), so the scientists are dealing with a very difficult hand. However, they should acknowledge that and temper their opinions accordingly.
JMHO,
HF

E.M.Smith says:
December 8, 2011 at 4:05 pm
“So, you see, you can have a process that has onset in one place (like Europe) and takes a hundred years, or maybe even 200, to spread around the globe to other places.”
Spot on. (It is called Empiricism – science, that is.)
Thanks for doing this spade work. Nomnom and his climate propaganda circle are working to wear us down. Their time is running short.