Geologist Dr. Sebastian Lüning and Prof. Fritz Vahrenholt found a Japanese tree-ring temperature reconstruction from 1995, one that should have been heeded by the IPCC and Michael Mann before they took the world on a 10-year joyride in the stolen car of “climate science”.
Here’s the Google translation of their article, with some fixes of my own to help it along written in [brackets]. I don’t vouch for total accuracy in the translation, but it is the best I can do.
UPDATE: 2:45PM PST Pierre Gosselin has graciously agreed to allow his translation to be posted here, so I’m eliminating the Google translate version – Anthony
By Sebastian Lüning & Fritz Vahrenholt
(Translated and reposted here at WUWT with permission, copyright English text NoTricksZone)
Leading representatives of the IPCC tried for years to have policymakers and citizens believe the pre-industrial temperature history was more or less uneventful and was the ideal climate ondition that we should all strive to maintain. The warming of the 20th century, on the other hand, was completely unusual, something dangerous. However, as we now know, the page turned a few years ago and the notorious Hockey Stick chapter ended. The flawed curve was taken off the market and the Medieval Warm Period and Little Ice Age reappeared.
As is often the case in history, it is in retrospect difficult to comprehend how this historical joyride could have happened to begin with. It started at the end of the 1990s with a doctoral thesis by Michael Mann, and did not end until about 10 years later – thanks to the discovery of the scientific scandal by Steve McIntyre and Ross McKitrick (see the book The Hockey Stick Illusion by Andrew Montford). Today it is difficult to fathom how the main players and proponents of the Hockey Sticks are still able to act as experts and public opinion shapers.
One of the main excuses used back then was that the Medieval Warm Period and Little Ice Age in Europe and North America were local phenomena. At other locations on the planet the temperature anomalies were more than evened out (e.g. Stefan Rahmstorf, Gerald Haug). For years we had to listen to their tales and we had to trust these “specialists” for better or for worse. Moreover, we paid them with our tax money so that they could deal exclusively with the climate and carry out the tedious work all this entails.
However, anyone who knew a little something about the scientific literature soon began to wonder. The Medieval Warm Period and the Little Ice Age as a local North Atlantic phenomenon? A nutty claim. Naturally these characteristic temperature fluctuations had been described for other parts of the world. Here we report on a case study from Japan which had appeared in the Geophysical Research Letters already in 1995, in other words, in the years before the Hockey Stick episode.
In the early 1990s, Japanese scientists Hiroyuki Kitagawa and Eiji Matsumoto extracted eleven tree ring cores from cedars on the South Pacific southern Japanese island of Yakushima. The cores contained tree-rings going back some 2000 years. The researchers determined the carbon 13 isotope values and found the delta-13-C values fluctuated in a characteristic manner (see Figure 1).
What did these fluctuations mean? Carbon-13 amount is influenced by a number of factors, among them temperature. The Japanese scientists calibrated the isotope development on trees of different elevations (and thereby temperature level) above sea level. Using this method they were able to come up with a formula that could be used for computing the temperature value using the isotope change. The results showed that temperatures over the previous 2000 years in South Japan fluctuated over a range of 5°C. The course of the temperature fluctuations takes on a shape that is very well known to us (see Figure 2). A clear millennium cycle is depicted. The cold period of the Migration Period, the Medieval Warm Period, the Little Ice Age and the Modern Warm Period are clearly recognisable. Moreover, this climate development is well documented in Japanese historical records.
Therefore, it is incomprehensible that with the clear Japanese data from the year 1995, the talk of a “local North Atlantic phenomenon” would go on for years after the data’s publication.
The two Japanese scientists even took it a step further. They carried out a detailed frequency analysis of their data and found characteristic cycles with periods in the range of several decades and centuries. Among others, they discovered a period of 187 years, which coincides with the known Suess/de Vries solar activity cycle. In a similar manner the 70 and 89-year Gleissberg-cycle was identified. In their results the authors saw a clear sign that the climate of the last 2000 years in southern Japan was predominantly influenced by solar activity fluctuations. The IPCC appears not to have been at all interested in the study. Indeed it did not fit with their climate catastrophe picture.
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NOTE: Commenter Peter Gulutzam made this observation in comments. The original Google translation correctly noted “…the southern Japanese island of Yakushima…” but Gosselin’s version incorrectly identifies it as a South Pacific Island. I’ve made the correction and notified Mr. Gosselin – Anthony
Did you know that several (Japanese) cedars in Yakushima are more than 3,000 years old?
tonyb says:
June 17, 2012 at 1:56 pm
Bearing in mind that we pour scorn on Manns tree rings as being an unreliable proxy for temperature for a myriad of reasons (limited growing season, susceptibility to local micro climates etc) we shouldn’t rush in to praise this study just because it tells us what we want to hear.
IF the methodology of using C13 to correlate to temperature is considered so accurate, as others say above, why don’t we apply it to other tree ring studies-such as Manns? Sorry, tree rings might be just about acceptable at dating or demonstrating moisture levels in the summer, but a global thermometer accurate to fractions of a degree? I don’t think so.
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I’m not qualified to say that C13 correlates to temperature or not. It sounds like what they did using C13 from indivual rings of many trees agrees with other data and historical records that show MWP and LIA. I think the “biggie” here is that there was a study using tree rings like Mann’s did (though he seems to have relied on just one tree ring) that didn’t show a hockey stick and, since it didn’t show humans had done something that needed to be taxed and controlled, was ignored by the IPCC.
I think the title should be “In Japan there Are No Hockey Sticks” to couple this to http://wattsupwiththat.com/2011/12/07/in-china-there-are-no-hockey-sticks/
I added that link to my list of all-time favorites in my guide to WUWT at http://home.comcast.net/~ewerme/wuwt/index.html , I ‘ll tack this one on too.
I think it’s much more important to link those two together than linking to Michael Mann.
Looking at the time axis, the reconstruction seems to end around 1950. Since about half the warming that makes up the blade of Mann’s hockey stick occurred since then, this would seem to account for some of the discrepancy. (The first graph above includes the recent instrumental record). This reconstruction being local rather than northern-hemispheric would also account for some more of the discrepancy, as others have noted. It is to be expected that it would have higher variance than a global reconstruction. Anyone knows the exact year this reconstruction ends?
Reblogged this on The GOLDEN RULE and commented:
A bit like flogging a dead horse, except that that statement literally applies to a useless object. The basis for alarmist AGW theory is scientifically unjustifiable, it remains alive and true. However, although the blogging supporters continue to believe it and persist in vocal defence, just as we persist in vocally advocating the injustice, the governments adopting “counter” warming schemes have already made their beds in which they can lie together with the IPCC and its masters.
Pierre-Normand says:
June 17, 2012 at 7:04 pm
Looking at the time axis, the reconstruction seems to end around 1950. Since about half the warming that makes up the blade of Mann’s hockey stick occurred since then, this would seem to account for some of the discrepancy>>>>
The point of contention here is the existance of the MWP, which this graph clearly shows, in opposition to Mann. The discrepancy in question has nothing to do with post 1950 temps.
In my opinion, Mann’s tree-ring reconstructions were never meant to find the MWP or LIA. They were meant to confirm the current warming, and proclaim it “unprecedented”.
All of the tree rings were put through a process that found those that correlated well with just the temp record. They never looked for those that found TWO items (temp record and MWP). If the entire series were re-run looking for the MWP or LIA, they’d probably find several trees that matched.
But they’d lose the hockey stick in the process.
Entirely off topic but here in the US it’s “Father’s Day”, so, Happy Father’s Day to all those to whom it may apply, whether you carry a hockey stick or not.
tonyb says:
June 17, 2012 at 1:56 pm
This is not a global study. Trying to apply C13 stuff to something like Mann’s might work, but there would have to be a clear methodology to link the C13 data from the different regions sampled. They’re good at splicing temperature to tree ring data, so I’m sure they could do it.
Given research that shows the MWP and LIA were global events, regional studies that don’t need to splice different sources have a place in the discussion. As with any scientific paper, the rsults should be reproduced and other proxies that do record sub-freezing periods should be examined if there are decent ones.
David,
The WMP extends from roughly AD 800 to AD 1400. Mann’s reconstruction featured above only extends back to 1000AD. It has very wide error bars back then. The temperature anomaly during the last part of the MWP is quite consistent with mid-twentieth century temperatures, albeit significantly below current temperatures.
It is difficult to make any genuine comparison with Kitagawa and Matsumoto. The spread in temperatures is about 4C, compared with Mann’s 1C. The anomaly during the MWP seems to be around +1C on average but we don’t know what the baseline calibration of the proxies were (What is the 0C anomaly relative to?). The last point in the graph features an anomaly or +2C around 1950. This would be much warmer than the MWP average! But it is merely local and this last temperature is not statistically significant anyway owing to the large variance.
I am not faulting Kitagawa and Matsumoto; only some of the inferences made here. Someone who can access the paper would usefully inform us of the the baseline of the temperature anomaly and the end date of the reconstruction.
People should not praise this proxy simply because they like the answer. Do any of the readers whose praise is so fulsome know anything about the reliability of C13 as a temperature proxy? Didn’t think so.
In addition, contrary to the assertions of the authors, this series has been used as a component in a number of multiproxy studies. It’s in the Yang et al 2002 China composite, which in turn is used in numerous multiproxy studies. I recall it being used in other studies, though I don’t recall which off hand.
The MWP-modern comparison is an interesting question, but no conclusions or moral should be drawn from this series.
Thanks Steve McIntyre. I see that there is a post on Climate Audit about Yang et al 2003 that features this proxy. And Yang et al 2003 is used in Mann and Jones 2003 among other places.
My only question is this: how many studies regardless of the source have to tell the same story about the LIA and MWP before we start to accept it as fact and that either these multiple studies somehow coincidently all came to this same result somewhat magically, or do we accept that perhaps somehow these are simple validation on each other?
I don’t think we should ever jump to conclusions based on ONE study, but at some point when you have study after study showing the same thing and that only faulty statistics as performed by Mann et al show the other side, you have to ask yourself whether we trust the results from bad statistical modeling or the multitude of studies that showed the same thing.
Now some may say that this is the same argument as Mann et al who said that countless other studies using the same faulty statistics justified and otherwise validates his methodology…however that is not the same thing. We are talking about different methods coming to the same conclusions. Doubtless, we can never say for certain what the past was like in the LIA and/or MWP as although multiple studies show the existance of both, they all seem to differ on the actual highs and lows and the in-betweens….but we can say for certain that any study that does not show them perhaps missed something somewhere.
KnR says:
Its always been an oddity that although the alarmists will tell us the MWP does not have enough evidenced to support the idea it was ‘world wide’. There more than happy for a far more restricted range of evidenced, indeed down to ‘one tree’ at times , to be more than enough to support the claim of climate doom.
That’s when they arn’t trying to flat out deny the MWP (along with the RWP and LIA).
I suspect they use a simple metric. If it supports their claims it’s “global”, if it dosn’t then it’s “local”.
Hu McCulloch says:
June 17, 2012 at 1:45 pm
d13C doesn’t necessarily have the same problems as TR width, so this may be a useful new class of proxies.
Indeed, this is the difference between using an established proxy and pseudo-proxies determined after the fact to be “proxies”.
Far from being forgotten, the Kitagawa & Matsumoto (1995) study has been used in various meta-analysis of proxy reconstructions. For example, Ljungqvist (2010) “A new reconstruction of temperature variability in the extra-tropical northern hemisphere during the last two millennia” which concludes (despite some differences with Briffa and Mann) that,
“Our new two-millennia long extra-tropical Northern Hemisphere (90–30°N) temperature recon-
struction supports a distinct Medieval Warm Period and an even more distinct Little Ice Age, fol- lowed by a rapid twentieth-century warming. We also find a pronounced Roman Warm Period and support for the Dark Age Cold Period. Our reconstruction is actually the first to show a Roman Warm Period as warm on a hemispheric scale as the twentieth century. The amplitude of the reconstructed temperature variability on centennial time-scales exceeds 0.6°C and thus supports the conclusions of those previous reconstructions that have shown the largest low-frequency pre-industrial temperature variability. Substantial parts of the Roman Warm Period, from the first to the third centuries, and the Medieval Warm Period, from the ninth to the thirteenth centuries, seem to have equalled or exceeded the AD 1961–1990 mean temperature level in the extra-tropical Northern Hemisphere. Since AD 1990, though, average temperatures in the extra-tropical Northern Hemisphere exceed those of any other warm decades the last two millennia, even the peak of the Medieval Warm Period, if we look at the instrumental temperature data spliced to the proxy re- construction.”
Unfortunately, it doesn’t support the idea that MWP temperatures were any warmer than at present.
As i made the comment first, I am delighted to be able to say that STeve M agrees with something I said 🙂
I would remind people that I do believe in the MWP and LIa and indeed have written on them. However, tree rings have many faults as a thermometer not the least being that trees have a short growing season and are suspectible to their local climate. In pointing to this grave shortcoming in Manns work we should also be sceptical of other tree rings studies purporting to pick up an a temperature signal of considerable accuracy.
I wrote about Manns Reconstructions (using mostly tree rings) here;
http://judithcurry.com/2011/12/01/the-long-slow-thaw/
tonyb
Apparently even Fritz Vahrenholt was not entirely certain of the results in his paper. He stated in an interview with European Energy Review that for many years he believed in the IPCC reports and even used a Hockey Stick graph in his presentations.
He realised that the IPCC had misguided people about the Medieval Warm Period after reading Andrew Montford’s book, The Hockey Stick Illusion, and learning about the difficulties encountered by Steve Mcintyre.
In 2010 he was asked to review a report by the IPCC into renewable energy. He found many errors and noted that much of the summary had been written by Greenpeace who concluded that by 2050, 80% of our energy could be produced by renewables. He found this unscientific and started to reconsider the IPCC’s Assessments.
He discovered that the IPCC was essentially a political organisation and that one third of the core writers of the 2007 Summary for Policymakers were connected to Greenpeace and the WWF. He wondered what people would think if the core writers had been from Exxon or Shell. “Would that be acceptable?” he asks.
He further states that climate models cannot simulate the Pacific decadal Oscillation or the Atlantic Multidecadal Oscillation and that these oscillations are moving into a cooling phase in tandem with the sun moving to a less active phase. As a result he predicts cooling until 2035 or even 2050.
Steve McIntyre says: June 17, 2012 at 9:27 pm
People should not praise this proxy simply because they like the answer. Do any of the readers whose praise is so fulsome know anything about the reliability of C13 as a temperature proxy? Didn’t think so.
As Steve, TonyB, and others have said, there is an issue. How can it be decided in a reasonable way, whether any measure is a good proxy?
I learned a lot when I compared the notorious Yamal treering proxy records to a lot of reasonably proximate thermometer records. It was clear that pretty well all the thermometer records moved in step over both short periods and long periods of time – whereas this did not happen with the treering records. To me, this discovery meant that I felt I could trust each of those thermometer records – because they jived with each other in many small and large details.
In this study, the oxygen isotope record has been shown to jive with several different factors, in a similar way. Solar cycles and elsewhere-recorded evidence for MWP and LIA. To me, these factors mutually reinforce each other.
This might seem like the rightly-failed technique of screening for fit between 1850 and 1900 – failed because it cannot help but produce hockey sticks. But it is not the same. It is requiring fits on several counts, much more like a key individually cut. Sure, in the end it could all be coincidence. But we can consider statistical probabilities on that too. And I think the Japanese study wins on these counts.
The other Phil says:
@Otter
Do you think this is a helpful way to advance the discussion?
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The above article has gained (from the count on my page elsewhere) over a hundred more viewers. Not much compared to this site, I know, but How many do you suppose will see it on stoke’s page?
The issue with tree rings is not the dating of the ring but to what extent one can extract a temperature profile/signal from the growth ring. In my opinion all tree ring studies fail because of the difficulty of extracting a true and representative temperature signal from the ring.
Since Japan is a narrow island nation growing conditions are likely to be heavily influenced by conditions of the surrounding oceans, and one may therefore expect to see some correlation with ocean cycles.
It cracks me up everytime the LIA is called “regional to the north atlantic”… When you go visit the glaciers in New Zealand’s south island, there are signs showing how far the glacier has retreated since the LIA… indeed, it was there that I learned about the LIA.
Otter, I wasn’t talking about the linking, but the insults.
On another thread I was going to ask why instead of attempting to use tree-ring widths as thermometers rather than simply looking at the isotopes in the rings. Cellulose binds up carbon and oxygen so there should both C13/C12 and O18/O16 both of which are known to correlate to temperature. Interestingly there actually are numerous studies that have been conducted – no time for links at the moment – and the ones I could actually look at all found evidence of events like the Little Ice Age. That may be sampling error, but …
What really is notable is that isotope studies on wood really do not seem to be popular with the team at all.
richard verney says:
June 18, 2012 at 2:28 am
The issue with tree rings is not the dating of the ring but to what extent one can extract a temperature profile/signal from the growth ring. In my opinion all tree ring studies fail because of the difficulty of extracting a true and representative temperature signal from the ring.
Since Japan is a narrow island nation growing conditions are likely to be heavily influenced by conditions of the surrounding oceans, and one may therefore expect to see some correlation with ocean cycles.
AGW climatology seems to be one of the few fields where tree-ring isotopes are are not used regularly. Isotope profiles from White Mountain Bristlecone pines were employed to calibrate C-14 profiles to yield better C-14 dates, since the rings give an absolute date. In fact those studies revealed the underestimate of the original half-life figure for C-14 as well. It should also be possible to obtain ratios of the hydrogen isotopes as well. In short wood should contain sever proxies that would provide a check on how well ring thickness correlates to temperature without even resorting to calibrating to thermometers.