Reposted from Jo Nova’s site
Chinese 2485 year tree ring study shows shows sun or ocean controls climate, temps will cool til 2068
A blockbuster Chinese study of Tibetan Tree rings by Lui et al 2011 shows, with detail, that the modern era is a dog-standard normal climate when compared to the last 2500 years. The temperature, the rate of change: it’s all been seen before. Nothing about the current period is “abnormal”, indeed the current warming period in Tibet can be produced through calculation of cycles. Lui et al do a fourier analysis on the underlying cycles and do a brave predictions as well.
In Tibet, it was about the same temperature on at least 4 occasions — back in late Roman times — blame the chariots, then again in the dark ages — blame the collapse of industry; then in the middle ages — blame the vikings; in modern times — blame the rise of industry. Clearly, these climate cycles have nothing to with human civilization. Their team finds natural cycles of many different lengths are at work: 2-3 years, 100 years, 199 years, 800 years, and 1324 year. The cold periods are associated with sunspot cycles. What we are not used to seeing are brave scientists willing to publish exact predictions of future temperatures for 100 years that include rises and falls. Apparently, it will cool til 2068, then warm again, though not to the same warmth as 2006 levels.
On “tree-rings”
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.
Some will also, rightly, point out this is just Tibet, not a global average. True. But the results agree reasonably well with hundreds of other studies from all around the world (from Midieval times, Roman times, the Greenland cores). Why can’t we do good tree-ring analysis like this from many locations?
Jo
Amplitudes, rates, periodicities and causes of temperature variations in the past 2485 years and future trends over the central-eastern Tibetan Plateau [Chinese Sci Bull,]
Figure 5 Prediction of temperature trends on the central-eastern Tibetan Plateau for the next 120 years. Blue line, initial series; orange line, calibration series, 464 BC–834 AD; purple line, verification series, 835–1980 AD; red line, forecasting series, 1980–2134 AD. (Click to enlarge)
There are beautiful graphs. Have a look at the power spectrum analysis and the cycles below…
ABSTRACT:
Amplitudes, rates, periodicities and causes of temperature variations in the past 2485 years and future trends over the central-eastern Tibetan Plateau
Amplitudes, rates, periodicities, causes and future trends of temperature variations based on tree rings for the past 2485 years on the central-eastern Tibetan Plateau were analyzed. The results showed that extreme climatic events on the Plateau, such as the Medieval Warm Period Little Ice Age and 20th Century Warming appeared synchronously with those in other places worldwide. The largest amplitude and rate of temperature change occurred during the Eastern Jin Event (343–425 AD), and not in the late 20th century. There were significant cycles of 1324 a, 800 a, 199 a, 110 a and 2–3 a in the 2485-year temperature series. The 1324 a, 800 a, 199 a and 110 a cycles are associated with solar activity, which greatly affects the Earth surface temperature. The long-term trends (>1000 a) of temperature were controlled by the millennium-scale cycle, and amplitudes were dominated by multi-century cycles. Moreover, cold intervals corresponded to sunspot minimums. The prediction indicated that the temperature will decrease in the future until to 2068 AD and then increase again.
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Figure 1 Tree-ring-based temperature reconstruction for the central-eastern Tibetan Plateau during the past 2485 years (gray line), the 40-year moving average (thick black line) and the 40-year running standard deviation (thin black line); the horizontal line is the mean temperature for the 2485 years. (Click to enlarge)
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Figure 2 Power spectrum analysis of the 2485-year temperature series. (Click to enlarge)
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Figure 3 Millennium-scale cycle in the temperature variation during the last 2485 years. (Click to enlarge)
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Figure 4 Decomposition of the main cycles of the 2485-year temperature series on the Tibetan Plateau and periodic function simulation. Top: Gray line,original series; red line, 1324 a cycle; green line, 199 a cycle; blue line, 110 a cycle. Bottom: Three sine functions for different timescales. 1324 a, red dashed line (y = 0.848 sin(0.005 t + 0.23)); 199 a, green line (y = 1.40 sin(0.032 t – 0.369)); 110 a, blue line (y = 1.875 sin(0.057 t + 2.846)); time t is the year from 484 BC to 2000 AD. (Click to enlarge)
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Conclusions
Climate events worldwide, such as the MWP and LIA, were seen in a 2485-year temperature series. The largest Figure 6 Temperature comparison between the forecast and observation data taken from seven stations on the central-eastern Tibetan Plateau (seven stations: Delingha, Dulan, Golmud, Lhasa, Nagqu, Dachaidan and Bange). amplitude and rate of temperature both occurred during the EJE, but not in the late 20th century. The millennium-scale cycle of solar activity determined the long-term temperature variation trends, while century-scale cycles controlled the amplitudes of temperature. Sunspot minimum events were associated with cold periods. The prediction results obtained using caterpillar-SSA showed that the temperature would increase until 2006 AD on the central-eastern Plateau, and then decrease until 2068 AD, and then increase again. 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. However, a decrease in temperature for a short period controlled by century- scale cycles cannot be excluded. Obviously, solar activity has greatly affected temperature on the central-eastern Plateau. However, there are still uncertainties in our understanding of climate change, and the concentration of CO2 affects the climate. Further investigations are thus needed. –
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REFERENCES
Liu Y, Cai Q F, Song H M, et al. Amplitudes, rates, periodicities and causes of temperature variations in the past 2485 years and future trends over the central-eastern Tibetan Plateau. Chinese Sci Bull, 2011, 56: 29862994, doi: 10.1007/s11434-011-4713-7 [ Climate Change over the Past Millennium in China.] … Hat Tip: Geoffrey Gold.
Matt: this is a multi-disciplinary Ijournal published by the Chinese Academy of Science. It is peer reviewed, has a high impact factor and an eminent editorial team. It incidentally has a very low self-citation score so carries a very low score on the toadyism index. That doesn’t mean the paper does not have flaws but the quality of the journal is not the issue.
There are more surprises on the way, in the past the RC would stop this:
http://www.realclimate.org/index.php/archives/2011/12/agu-2011-day-2/
see comment #1.
I wonder if these scientist could apply their methods to the questionable tree ring studies?
As an aside, I am shocked that scientists could just publish without any concern for the damage that may be inflicted upon the ‘team’!! 🙂
i’d love to know what mcintyre and jeff id think about that reconstruction. guess they would debunk it.
Thank you. Yes, I missed it. So there does seem to be a longer period signal, I “eyeballed” it a >700 years but as you say, the record isn’t long enough for any accuracy at that wavelength. The 60 year cycle seems to show up in many different records of all sorts, even in lake bed sediment core pollen surveys, the 60 year Chinese calendar, all sorts of things: http://hockeyschtick.blogspot.com/2010/04/more-on-60-year-climate-cycle.html
This isn’t the first time that it has been noted.
It looks as though the date range for the LIA and the MWP was different in China. (That’s OK–our side has often argued that there’s no such thing as a global temperature, but rather that regions have their own trends that are only loosely linked to one another.) The main point is that at roughly the same time as our MWP and other warming periods there were higher temperatures than now in Asia is the important thing.
Not to worry, this is voodoo science. You can be assured, Earth will keep warming and polar bears will keep melting!
bushbunny says:
December 7, 2011 at 11:07 pm
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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.
Larry as far as I know that the LIA started sometime in the 14th Century and gradually on and off
some years warmer than the last, but generally much colder with short seasons, and more snow and ice. But in the 18th and 19th century the Thames froze over and they had ice fairs. England and UK generally the LIA ended around mid 1850, and it started
to get warmer gradually with some cold seasons. 1947 was an exceptional cold winter, and in 1963 the Thames froze as far as Windsor. But one good thing well in a way. They had poor wine
harvests and England stopped growing grapes. But they turned the old presses into printing presses. So the impact on humanity was immense. There was a way eventually to educate the masses. Less wine, more thought, LOL. Prefer both myself.
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.
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.
I’m sorry to see this faux argument keep on reappearing. It would be nice to see a whole post on the scientific propriety of working with significant correlations, whether or not they have explanations. A post to remind us that we still don’t really understand how gravity works, for instance, despite having an extremely high predictive ability in this area.
This is a brilliant paper. Yes, it goes a long way to rehabilitate treerings as temperature proxies.
However, I would like to see corroborative studies of treeline shifts from this locality. I still get the feeling that these may indicate longterm large shifts rather better.
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?
@ur momisugly crosspatch and Vukcevic
Has anyone attempted to compile a composite of the known cycles (i.e. AMO, PDO, sun cycles, etc) and see if there could be a correlation with regards to various cycles peaking at the same point in time and therefore causing 60 year, 100 year, 800 year, or whatever peak and troughs in the global temps? In other words, numerous amplication factors to highs (or lows) happening at the same point in time amplifying temp.
My math expertise expired a long time ago so I’m just a puppy here now.
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.
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.
I don’t think it is a big step from there to suggest that increased crop yields are good for the human race, thus whatever else tree rings show, they are a good proxy for human well-being.
Can anyone suggest any holes in my logic?
Much cleaner than the Hockey Stick I think. No discarding of data and replacing it with an unrelated data set (Hiding the decline + Nature Trick). No gratuitous PCA analysis. And I doubt we will find in a decade that deliberate deceit looks to have been involved.
But still it involves a dubious metric — tree ring width. It uses a technology — Fourier analysis — that always provides an answer for any data assemblage but provides no indication (e.g. variance) about the quality of the answer. And we don’t really know what causes the “decline” that Jones was concerned about hiding and whether that decline is present in the Chinese data.
Lots we don’t know. But certainly worthy of publication.
crosspatch says:
December 8, 2011 at 1:10 am
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.
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crosspatch, I think you hit the nail on the head.
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. It would also be close to proving the fraud in the global warming swindle.This has been my suspicion for the past year or so. Oh how I wish that would show up in an email exchange.
The great swindle would be much easier to explain than the collective ignorance of these people.
Finally! Tree rings you can believe in!
Do Chinese tree rings track local temps (unlike Russian ones)?
1. How many trees did they analyse?
2. What trees were they?
3.Why are they better than bristlecone pine?
eyesonu
Joe D’Aleo has put together a composite PDO/AMO index curve and plotted it against US temperature records.
I don’t know of anyone who has combined further cycles in models.
I do know that Piers Corbyn has noted certain cycles on the centennial scale which combine solar and lunar factors, but as he runs a private company he doesn’t do academic publications.
It’s certainly one of the key areas for climate modelling/prediction right now………..
eyesonu says:
December 8, 2011 at 1:16 am
“Has anyone attempted to compile a composite of the known cycles (i.e. AMO, PDO, sun cycles, etc) and see if there could be a correlation with regards to various cycles”
There is a clear pattern in the instrumental record of the past 130 years showing how the warming and cooling alternates at 30 year intervals (60 year cycle). You don’t need any ‘maths expertise’ to see this; the Woodfortrees site allows you to plot graphs highlighting this trend.
http://www.woodfortrees.org/plot/hadcrut3gl/from:1880/to:2011/plot/hadcrut3gl/from:1880/to:1910/trend/plot/hadcrut3gl/from:1911/to:1940/trend/plot/hadcrut3gl/from:1941/to:1970/trend/plot/hadcrut3gl/from:1971/to:2000/trend/plot/hadcrut3gl/from:2001/to:2011/trend
See how the temperature falls from 1880 to 1910; rises from 1910 to 1940; falls from 1940 to 1970; rises from 1970 to 2000 and then levels out or falls thereafter. If this pattern is maintained, we can expect cooling for another 20 years.
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.
On that very first chart… of course you realize, they’d snip everything before 1800 and say ‘Look! Precipitouse rise in temperatures…!’
Wait. That is EXACTLY what they’ve been doing…
While the study of tree rings to determine historical climates is more climatology than climate science, it can provide reasonably accurate trends with a big enough unbiased sample..
Caveat: That is as long as the members of the Team don’t get to manipulate (apply Mannian Maths, or something similar) to the original data.
IPCC Fantasy 5 will undoubtedly ignore this in favour of the much beloved, and totally discredited, Hockey Stick.
Thats just Tibet, i.e. local climate. The heroic deeds of Mann were global!!! Plus they are Chinese… under the pay of big coal and communism. /sarc