Shock, awe. Untruncated and unspliced data used in a new paper from Briffa and Melvin at UEA restores the Medieval Warm Period while at the same time disappears Mann’s hockey stick. Here’s figure 5 that tells the story:
Look at graph 5c, and you’ll see 20th century warmth matches peaks either side of the year 1000, and that for the TRW chronology 20th century warmth is less than the spike around 1750. This puts 20th century (up to 2006 actually) warmth in the category of just another blip. There’s no obvious hockey stick, and the MWP returns, though approximately equal to 20th century warmth rather than being warmer.
Whoo boy, I suspect this paper will be called in the Mann -vs- Steyn trial (if it ever makes it that far; the judge may throw it out because the legal pleading makes a false claim by Mann). What is most curious here is that it was Briffa (in the Climategate emails) who was arguing that some claims about his post 1960 MXD series data as used in other papers might not be valid. It set the stage for “Mikes Nature trick” and “hide the decline“. Steve McIntyre wrote about it all the way back in 2005:
A Strange Truncation of the Briffa MXD Series
Post-1960 values of the Briffa MXD series are deleted from the IPCC TAR multiproxy spaghetti graph. These values trend downward in the original citation (Briffa [2000], see Figure 5), where post-1960 values are shown. The effect of deleting the post-1960 values of the Briffa MXD series is to make the reconstructions more “similar”. The truncation is not documented in IPCC TAR.
I have to wonder if this is some sort of attempt to “come clean” on the issue. Mann must be furious at the timing. There’s no hint of a hockey stick, and no need to splice on the instrumental surface temperature record or play “hide the decline” tricks with this data.
Bishop Hill writes:
Well, well, well.
In its previous incarnation, without a MWP, the series was used in:
- MBH98
- MBH99
- Rutherford et al 05
- Jones 98
- Crowley 00
- Briffa 00
- Esper 02
- Mann, Jones 03
- Moberg
- Osborn, Briffa 06
- D’Arrigo et al 06
It rather puts all that previous work in perspective, since this new paper has identified and corrected the biases. It should be noted though that tree ring paleoclimatology is an inexact science, and as we’ve seen, even a single tree can go a long way to distorting the output. On the plus side, it is good to see that this paper defines and corrects biases present in the MXD and TRW series of the Tornetraesk tree ring chronology dataset. This is a positive step forward. I suspect there will be a flurry of papers trying to counter this to save Mann’s Hockey Stick.
From the journal Holocene:
Potential bias in ‘updating’ tree-ring chronologies using regional curve standardisation: Re-processing 1500 years of Torneträsk density and ring-width data
Thomas M Melvin University of East Anglia, UK
Håkan Grudd Department of Physical Geography and Quaternary Geology, Stockholm University, Sweden
Keith R Briffa University of East Anglia, UK
Abstract
We describe the analysis of existing and new maximum-latewood-density (MXD) and tree-ring width (TRW) data from the Torneträsk region of northern Sweden and the construction of 1500 year chronologies. Some previous work found that MXD and TRW chronologies from Torneträsk were inconsistent over the most recent 200 years, even though they both reflect predominantly summer temperature influences on tree growth. We show that this was partly a result of systematic bias in MXD data measurements and partly a result of inhomogeneous sample selection from living trees (modern sample bias). We use refinements of the simple Regional Curve Standardisation (RCS) method of chronology construction to identify and mitigate these biases. The new MXD and TRW chronologies now present a largely consistent picture of long-timescale changes in past summer temperature in this region over their full length, indicating similar levels of summer warmth in the medieval period (MWP, c. CE 900–1100) and the latter half of the 20th century. Future work involving the updating of MXD chronologies using differently sourced measurements may require similar analysis and appropriate adjustment to that described here to make the data suitable for the production of un-biased RCS chronologies. The use of ‘growth-rate’ based multiple RCS curves is recommended to identify and mitigate the problem of ‘modern sample bias’.
Here’s the money quote from the paper:
If the good fit between these tree-growth and temperature data is reflected at the longer timescales indicated by the smoothed chronologies (Figures 5c and S20d, available online), we can infer the existence of generally warm summers in the 10th and 11th centuries, similar to the level of those in the 20th century.
Conclusions
• The RCS method generates long-timescale variance from
the absolute values of measurements but it is important to
test that data from different sources are compatible in
order to avoid systematic bias in chronologies.
• It was found in the Torneträsk region of Sweden that there were systematic differences in the density measurements from different analytical procedures and laboratory conditions and that an RCS chronology created from a simple combination of these MXD data contained systematic bias.
• Both the known systematic variation of measurement values (both TRW and MXD) by ring age and the varying effect of common forcing on tree growth over time must
be taken into account when assessing the need to adjust subpopulations of tree-growth measurements for use with RCS.
• It was necessary to rescale the ‘update’ density measurements from Torneträsk to match the earlier measurements over their common period, after accounting for ring-age decay, in order to remove this systematic bias.
• The use of two RCS curves, separately processing fastand slow-growing trees, has reduced the effect of modern sample bias which appears to have produced some artificial inflation of chronology values in the late 20th century in previously published Torneträsk TRW chronologies.
• A ‘signal-free’ implementation of a multiple RCS approach to remove the tree age-related trends, while retaining trends associated with climate, has produced
new 1500-year long MXD and TRW chronologies which show similar evidence of long-timescale changes over
their full length.
• The new chronologies presented here provide mutually consistent evidence, contradicting a previously published conclusion (Grudd, 2008), that medieval summers (between 900 and 1100 ce) were much warmer than those
in the 20th century.
• The method described here to test for and remove systematic bias from RCS chronologies is recommended for further studies where it is necessary to identify and mitigate systematic bias in RCS chronologies composed of nonhomogeneous samples.
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I asked Anthony Watts the question,
Is the resubmitted one going to be posted here? I just want to know.
and he replied
REPLY: I assume you can answer this question yourself – Anthony
I take this as a “No”.
This is, of course, up to you, it’s your blog, you are the dictator here, and you can do as you like, post what you like and do not post what you don’t like or the other way around. I wonder, though, why you asked me to rephrase the criticized wording and to resubmit, if you don’t post it anyhow. Are you trying to keep me busy?
REPLY: Unless we are talking about different comments, it is right above you on this thread. There’s nothing in que for you. – Anthony
Joeldshore says:
October 30, 2012 at 5:32 am
So, no, we aren’t in the Dark Ages where we have no understanding of the basic processes that govern the physical universe and are ignorant of basic statistical fluctuations to boot.
Phil Jones:
“We don’t know what natural variability is doing.”
richardscourtney says:
October 30, 2012 at 6:51 am
In conclusion, it can be stated that global warming discernible with 90% confidence stopped 16 years ago.
Jan P Perlwitz says:
October 30, 2012 at 10:51 am
The discussion was about global warming since 1970 and the fact that it stopped 16 years ago.
This is only a fact in Courtney’s fantasy, since he hasn’t provided any shred of evidence for this assertion.
Attributed to Phil Jones: Yet he insisted that 15 or 16 years is not a significant period: pauses of such length had always been expected, he said.
Does this mean Phil Jones and Richard Courtney share a common fantasy?
Anthony Watts wrote:
This seems to have been just a misunderstanding, then. Yes, we are talking about different comments. I’m going to resubmit the replacement comment for the snipped one.
richardscourtney wrote in
http://wattsupwiththat.com/2012/10/28/manns-hockey-stick-disappears-and-crus-briffa-helps-make-the-mwp-live-again-by-pointing-out-bias-in-ther-data/#comment-1128889
Courtney is disseminating falsehoods again. He states the assertion, “global warming stopped 16 years ago”. I asked for the evidence for this assertion, and I showed with some data sets that there are discernible trends over the last 16 years in most of those sets, which are not statistically significant at a significance level of 95%, though. I compared those trends to the trends in a similar 16-year period, 1980 to 1995, when global warming didn’t stop either, even though the trends were not statistically significant at 95% during that period. Contrarily to Courtney’s falsehood, nowhere did I say the data I presented supported that global warming did not stop. Instead, I say the temperature data do not provide the evidence for Courtney’s assertion that global warming stopped.
Courtney hasn’t provided any empirical evidence for his assertion that global warming “stopped”. He can’t because there is no empirical evidence for this assertion. Courtney only abuses statistical analysis and draws logically false, i.e., scientifically flawed conclusions from it.
The burden of proof for the assertion that global warming “stopped” is on Courtney and all the ones who state this assertion. They have not delivered so far.
However, it is obvious that Courtney believes when he shows a trend is not “discernible” or statistically significant in a time series that such a result falsified the presence of the trend. He has argued repeatedly in this way. However, by arguing in this way Courtney has only proven that he is absolutely clueless with respect to statistical analysis and the conclusion that can validly be drawn from the fact that a test for statistical significance fails.
Perlwitz says:
“Are you trying to keep me busy?:
Someone needs to. I’m talking about your boss, who apparently approves of your constant posting on blogs throughout you taxpayer-paid work day. You and your boss are both corrupt.
Your boss is the scofflaw James Hansen. Right?
I do want to point out that, to a significant degree, all the talk about statistical significance is not even wrong. One cannot know if something is statistically significant without knowing the correlations of the underlying process. Most statistical tests make assumptions, such as that the errors are i.i.d.. If they are not actually so distributed, then the tests based on that assumption are, at best, only moderately informed guesses.
And, that is how you quickly get into situations where “eyeballing” is, in fact, the best you can do. Anyone who can look at the last 30 years of data and not recognize that there has been a substantial deviation in the rate of change of the global temperature metric is just fooling himself. And, you all know what Prof. Feynman said of that.
Friends:
I write to ask some questions. I need to recap to ask them.
1.
The troll claimed the discussion was not about the fact that global warming stopped 16 years ago.
2.
I quoted the troll questioning my statement that global warming stopped 16 years ago and asking justification for it.
3.
I pointed out that the subsequent discussion was about answers to his questions and their validity.
4.
At October 30, 2012 at 1:18 pm the troll writes
I have some difficulty understanding that obtuse drivel, but I think it tries to assert that I was “lying” because I accurately quoted the troll.
So, my question is
Does anyone have an alternative understanding of the troll’s drivel?
Richard
Leif Svalgaard says:
October 30, 2012 at 1:29 pm
vukcevic says:
October 30, 2012 at 1:01 pm
N. Atlantic data, most of it from Danish records
congratulations! you have discovered a 200-yr cycle in NAP that matches the 100-yr cycle in SSN every 2nd cycle. This could be the discovery of the century, or of the last centuries.
……
No idea what you are talking about. Congratulations are due to you relatives from the land of fire and ice, and they were not recording the ice (do you want the data?).
You might like to do some calculations using geomagnetic storms induction as a trigger but don’t expect it to happen there and then: http://hal.inria.fr/docs/00/06/68/65/PDF/2004JB003282.pdf
Bart:
At October 30, 2012 at 2:46 pm you rightly say
YES!
Indeed, I mentioned that in my post at October 30, 2012 at 6:51 am where I wrote
The only disputable part of that is its final statement because it could be interpreted as saying,
“It is alright to do it wrong because others do”
although it is intended to mean
“Climastrologists won’t complain if results are presented in the same form as they present results”.
(Of course, the troll will complain at anything if it does not support the AGW-scare which is giving him a living so his complaints can be disregarded).
Richard
From Leif Svalgaard on October 30, 2012 at 1:29 pm:
Ah Leif, you are intriguing me!
Following the time-honored principle that if a moron can find the same result then it is nothing special and likely wrong, I am attempting my own SSN curve fitting. (Possibly I’ll find something different, as in nothing.) Yearly values with pre-1946 correction, just playing. Matching up the minimums, I found the best match was with a cycle length of 11.15 years.
So the (approximately?) 100 yr cycle is nine sunspot cycles in length (100.35).
Now I want to know why it would be nine times.
Time to load up the monthly 12-mo smoothed and see if the match is still there.
vukcevic says:
October 30, 2012 at 2:59 pm
You might like to do some calculations using geomagnetic storms induction as a trigger
It is precisely that high conductivity that screens the core from any external influence, in combination with the high conductivity [effectively a superconductor] of the core itself. Then skin depth is small, in the mantle about 50 km and in the core only 200 m for a disturbance lasting one day [typical for a geomagnetic storm]. This is well-known and need not be computed again. The result is that geomagnetic storms do not penetrate into the core to alter the magnetic field there. I think I have explained that several times by now.
What happened to your grandiose plan of carpet-bombing geophysics departments with your ‘paper’?
Bart
“Anyone who can look at the last 30 years of data and not recognize that there has been a substantial deviation in the rate of change of the global temperature metric is just fooling himself.”
When the rising temps have gone up for the same amount of time that they have stopped ~16 years, during which the entire Global Warming alarm industry was created, this latter 16 year period is huge statistically. It has caused the entire movement to have to hum and haw about overprint of natural variability (a factor that was considered small before now) and that the models say 16 years flat is perfectly okay. It is statistically huge when you realize that all the stuff they have put out in IPCC terror with 95% confidence over the years and 4 to 6 degrees rise by 2100 being tailored down to 3 -6 and now ~ 2 or so. It is huge statistically when the agents of doom have added step-wise increases to the record for recent temps and decreases to earlier temps. It is huge when the record 1934 was beaten down over half a dozen years to make 1998 the hottest year of the last millennium. It is huge when the very people who cooked this whole thing are the ones saying the 16 year hiatus is no big deal. In fact, with 1934 the record, we have had a 78 year zero trend. With the MWP being reinstated, maybe we have an 800 year period of no trend – now that is huge.
Perlwitz says:
“I’m waiting for an answer.”
It was tempting to make you wait.
Anyway, as a taxpayer I am entitled to point out when someone is screwing off, instead of doing the job the public pays them to do. And I’m sure your written job description does not say you get to sit around and post comments on blogs throughout your work day. Other GISS employees don’t do it. Why do you?
How much does your pay and benefits package cost the hard-bitten taxpayers? Whatever it is, you are not worth it. If you didn’t show up for work after today, the world would keep turning. There would be zero downside. The taxpaying public would be better off. And AGW would still be an evidence-free conjecture.
kadaka (KD Knoebel) says:
October 30, 2012 at 3:21 pm
Ah Leif, you are intriguing me!
Please don’t take my joke seriously 🙂
Now I want to know why it would be nine times.
Perhaps due to the planets 🙂
Anyway, the ‘100’-year cycle is not a real cycle, only a coincidence that have been there the last two or three centuries. Already Rudolf Wolf [who first determined the cycle length] found 11 and 1/9 years, so exactly nine cycles per century. Unfortunately, the cycle length varies, both from cycle to cycle, but also a bit from century to century. The length of the cycle is probably determined by the rotation of the sun [faster = shorter cycle] and by age [faster = young]. We see that in other stars.
Bart wrote in
http://wattsupwiththat.com/2012/10/28/manns-hockey-stick-disappears-and-crus-briffa-helps-make-the-mwp-live-again-by-pointing-out-bias-in-ther-data/#comment-1129670
Like the “substantial deviation in the rate of change of the global temperature metric” in the 16-year time period 1980 to 1995?
Here are the trends with the 2-sigma ranges for the same data sets from above for this time period, using the trend calculator at http://www.skepticalscience.com/trend.php again:
GISSTEMP: 0.048+/-0.159
NOAA: 0.085+/-0.138
HADCRUT4: 0.097+/-0.138
RSS: 0.023+/-0.228
UAH: -0.012+/-0.241
Look, how similar these 16-year trends are compared to the recent 16 years.
So, consequentially, anyone who claims such a “substantial deviation” in recent years or that global warming “stopped” 16 years ago, would also have to claim that there was a very similar “deviation” or that global warming “stopped” also from 1980 to 1995.
Then again, the temperature increase from 1980 to today is clearly statistically significant with at least 95% probability. And not just so.
GISSTEMP: 0.151+/-0.048
NOAA: 0.151+/-0.045
HADCRUT4: 0.159+/-0.046
RSS: 0.135+/-0.078
UAH: 0.141+/-0.078
So, global warming is supposed to have “stopped” between the start of 1980 and the end of 1995, and global warming is supposed to have “stopped” again 16 years ago, starting in November 1996. When is all the warming supposed to have happened then that made the trend from 1980 to today as clearly statistically significant? It leaves only the period from January 1996 to October 1996, doesn’t it? Now, this can’t be true, either. The trend from January 1996 to October 1996 is not statistically significant, either. So, no global warming in this period, either.
Thus, no “discernible” global warming from 1980 to 1995, no “discernible” global warming from January 1996 to October 1996, and no “discernible” global warming from November 1996 to today. According to this, there hasn’t been any “discernible” global warming during any time from 1980 to today, looking at the partial time periods separately. And yet, looking at the whole time period there has been statistically significant global warming.
No global warming and statistically significant global warming at the same time. Both statements can’t be true at the same time, though. The solution for this conundrum is that the conclusions about no global warming are based on too short time series used for the statistical analysis. Absence of a detectability of a trend does not logically imply the absence of a trend, since it can’t be logically excluded the possibility that the absence of detectability is only due to insufficient data.
On a side note: The trends above for the period 1980 to 1995 also show that the recent assertions by David Rose in the Daily Mail and by Judith Curry, according to whom the recent time period was something different to what had been observed before in the temperature record since the 1970ies are false. Something very similar had been observed before from 1980 to 1995. Curry and Rose used the trick for their assertion, though, to compare a 17-year time period, 1980 to 1996, with the recent time period, where the recent time period wasn’t even full 16 years, more like 15 years instead. One year can make a big difference.
Gary Pearse:
I agree with the point you are making in your post at October 30, 2012 at 3:37 pm but, with respect, I think you are missing the importance of the true statements made by Bart.
All you say is true, but the excuse for all of it is AGW which it is asserted has caused, is causing and will cause global warming. And global warming stopped 16 years ago.
Those who have a vested interest in the AGW-scare are trying to claim both that
(a) AGW has not stopped
and
(b) the stop is not evidence against AGW.
If you doubt they are making these mutually exclusive claims then read the posts from the troll in this thread.
Their excuse for their claims is blatantly erroneous statistical analyses. This is not unusual for such people. The true purpose of this thread is to discuss the paper of Briffa which compares to the statistically flawed analysis of Mann, Bradley and Hughes which provided the infamous ‘hockey stick’ graph.
Bart is pointing out that those promoting the AGW-scare are using a false excuse for the cessation of global warming and, therefore, their claims – which I list as (a) and (b) – are wrong.
He is giving you strong evidence for your point.
Richard
“D Böehm” wrote in
http://wattsupwiththat.com/2012/10/28/manns-hockey-stick-disappears-and-crus-briffa-helps-make-the-mwp-live-again-by-pointing-out-bias-in-ther-data/#comment-1129739
Well, I’m still waiting, since my questions I asked in
http://wattsupwiththat.com/2012/10/28/manns-hockey-stick-disappears-and-crus-briffa-helps-make-the-mwp-live-again-by-pointing-out-bias-in-ther-data/#comment-1129684
were not answered. But maybe someone else can help “D Böehm”?
I’m very certain that I will have to wait forever, before I get a straight answer, since no one has entitled “D Böehm” to impose on me at what times I must work and when I’m allowed to do something else (and not even allowed to work at these other times, instead?). And there is no law that gives “D Böehm” this entitlement or anyone else, only because they were taxpayers.
And to answer your question from your previous post. No, Jim Hansen is not by boss.
Gary Pearse says:
October 30, 2012 at 3:37 pm
We are not in disagreement. I was addressing the claim that lull of the past 16 years is not “statistically significant”. That claim has no rigorous backing, any more than did the claims for what came before. There is no conclusive, not even preponderant, evidence that we have experienced anything other than a natural trend with natural variation.
OOPS!
I intended to write
(a) global warming has not stopped
Sorry.
Richard
richardscourtney wrote in
http://wattsupwiththat.com/2012/10/28/manns-hockey-stick-disappears-and-crus-briffa-helps-make-the-mwp-live-again-by-pointing-out-bias-in-ther-data/#comment-1129682
Courtney is only repeating his lie from before. I never claimed such a thing.
Leif Svalgaard says: October 30, 2012 at 3:37 pm
…………….
You got it, and that is where the action comes from, ask your iceland’s relatives
http://www.vukcevic.talktalk.net/SSN-NAP.htm
sun and the Earth in the North Atlantic.
http://www.vukcevic.talktalk.net/EarthNV.htm
as for the core it’s a bit of a bore, but ‘one has to go with the flow’.
grandiose plan ? Ahh, my dear friend Leef Svalbaard.
The Wikipedia Solar variation entry has been processed and sanitized by the (C)AGW-pushers for the protection of the brainwashed. Small example: Nevertheless, Solanki agrees with the scientific consensus that the marked upswing in temperatures since about 1980 is attributable to human activity. Etc.
Did find this:
and this:
I don’t think that page gets updated very often. Ref 38 was Hathaway and Wilson 2004, “What the Sunspot Record Tells Us About Space Climate”. Free download.
Paper reveals that last bit from Wikipedia was lifted straight from the Abstract, thus missing the nine other characteristics that preceded the Gleissberg cycle.
145+/-30 maximum smoothed in 2010? The sum of all monthly smoothed numbers in 2010 was 210.7.
I have seen 11.1 years given for the sunspot cycle length before. Yet somehow on Wikipedia’s List of solar cycles, the mean of solar cycles 1 to 23 was only 10.6 years. Go figure.
Bart says:
The problem in this case is that the human brain is too good a pattern recognition device. It often sees patterns in random data when the patterns aren’t really there.
It is not hard to demonstrate this sort of thing in this particular case by creating “artificial data” that has a linear trend plus some sort of random noise. One then can find segments of that data where it looks to the eye like the trend has stopped (and, of course, is even “confirmed” in the sense that if you do a linear fit over that interval then you find a negative slope). But we know the underlying trend hasn’t stopped because the “data” was explicitly created with a linear trend. Tamino had a nice demo of this sort of thing once.
For the record, as this thread shows, I have asked climate scientist Jan Perlw1tz two questions. One in regard to what aspects of the Briffa paper above cannot be understood by someone outside of the climate research field, and the other in regard to the cause of late springs in years with little or no snowfall.
Having been repeatedly asked these questions, and having had ample time to respond, he has not. We are left to draw our own conclusions as to why.
My expectation is that he will not answer the first question because there is nothing in that paper that would require any knowledge specific to climate research to understand, and the second because he doesn’t know.
vukcevic says:
October 30, 2012 at 4:48 pm
and that is where the action comes from
“The easiest one to fool is oneself”.