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.
More on Briffa – perhaps a decent chap, perhaps just trying to walk that fine line (maybe he just got swamped by the system):
From climategate emails:
cc: ???@unixg.ubc.ca (Steve Calvert), ???@ocean.seos.uvic.ca
date: Thu Aug 5 12:07:07 1999
from: Keith Briffa
subject: Re: Skeptics
to: Tom Pedersen , ???@climate1.geo.umass.edu
Temperature reconstructions based on ring density have an opposite bias – reduced density in recent years that may similarly be expressed to different degrees depending on the method of data processing and which would in any case suppress evidence of recent warming. This may or may not be associated directly with the effects of CO2 or other fertilization.
Our density reconstructions still show the 20th century to be anomalously warm in a several hundred year context , and perhaps much longer one.
The problem here is a genuine paucity of long series and statistical problems in processing and calibrating such data.
We need to and are, doing much more work to explore these……
I for one still believe that we are seeing the manifestation of greenhouse warming but I know the evidence presented to date leaves many questions still unanswered .
I too believe that solar variability is a potential forcing factor that has likely contributed to the variability of 19th and 20th century observations .
The extent of the effect surely requires much more model-based research.
Simply correlating Hoyt’s series against observations or reconstructed temperatures does not get us far.
I also believe we have major uncertainty surrounding global or hemispheric estimates of centennial or millennial reconstructions , and real problems with spacial patterns on long timescales.
Saying this does not make me an outlaw in the palaeo family – I hope! – just someone anxious to maintain our objectivity.
We should all resist the attempts of those who try to push us into the pro or anti greenhouse camps.
I think Hoyt’s comments betray someone who is perhaps lacking the degree of objectivity I had previously thought him to have.
Nicola Scafetta says:
October 28, 2012 at 5:56 pm
So, also the other referees were poor scientists unfamiliar and possible hostile on this topic.
I know that your definition of a poor scientist is one that is not enthusiastic about your papers…
By the way, my two accepted papers were refereed by 4 people plus the editor and everybody agreed that the papers had to be published and were free of errors.
If you try hard enough and long enough you eventually find a journal that will take your stuff.
Nicola Scafetta says:
October 28, 2012 at 5:56 pm
By the way, my two accepted papers were refereed by 4 people plus the editor and everybody agreed that the papers had to be published and were free of errors.
How many referees and editors were there on all yours papers that were rejected?
D Boehm says:
Well then, I am sure you will have no trouble whatsoever pointing to the post where I made that assertion? Here’s a couple that might help you: 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-1126559 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-1126537 …Or maybe not!
Nicola Scafetta says:
That’s pretty impressive. Do they give a money-back guarantee? In the journals that I have published in or refereed for, there are no guarantees given or expected from referees as to whether the papers are free of errors. Certainly, the journals ask one to assess validity as best as one can and to find errors as well as one can but they certainly don’t expect referees to determine definitively if the paper is error-free.
OMG!!
Leif: “I only try to make sure that the solar data is correct”
Says it all..
Figure 5c shows a spike in approx 1750, which is reported to be the coldest part of the LIA. Historical records from England suggest they were skating on the Thames during many winters from early 1700’s to 1830.
So why the spike then? What am I missing?
joelshore,
You are an apologist for Michael Mann. But if your position now is that there was a global MWP and a global LIA, post it here.
Dr. Svalgaard – I have no idea which of you two represent more of the ‘mainstream’ in your area of expertise, however, the argument of “which journal published your paper” is on pretty thin ice in these circles. I know its way OT (and likely over all of our heads), but these types of arguments should consist of facts and dialog, not mere argument by journal association.
joeldshore;
Nonetheless, I don’t think it matters. The IPCC quote refers to Briffa work covering “sites across northern Fennoscandia and northern Siberia”. The current Briffa paper seems to refer only to “the Torneträsk region of northern Sweden”.
>>>>>>>>>>>>>>>>>>>
I suppose we’re splitting hairs at this point. My understanding is that this data series is a subset of the ones you refer to, which in turn were cited by the IPCC as a proxy for NH temps, just as I pointed out. Now when we consider the larger data set being referenced by the IPCC, in the context of this paper, that statement by the IPCC becomes highly questionable on several grounds.
1. This work shows that the techniques employed in Briffa 2002 and 2004 need to be corrected across the board. In other words, if this paper is correct, then all the other data series in the Fennoscandia and northern Siberia series also need to be corrected. Which in turn means that they will no longer be correlated to the temperature record for the NH and so the IPCC conclusion must be discarded. Or….
2. If none of the other data series need to be corrected (only this one) the effect would be that the Fennoscandia series with the corrected data would no longer correlate to northern Siberia, meaning that the two areas are not sychronised. Since their being synchronised was a large part of the argument that they represented NH temps, this IPCC conclusion would have to be discarded in this case also.
Either way, Briffa et al 2012 pretty much falsifies 2002, 2004, and the IPCC conclusion.
Leif Svalgaard says:
October 28, 2012 at 4:36 pm
Sure, after having been rejected by other journals, they finally found one that would take it.
tallbloke says:
October 28, 2012 at 4:56 pm
Which journals rejected their paper, to your knowledge?
Leif Svalgaard says:
October 28, 2012 at 5:19 pm
Why don’t you ask them?
===========
Surely suggesting a scientist’s paper has “been rejected by other journals” is not something nice to say, especially if it may not be true. So why say it if you did not know it for a fact at the time?
If you have played fast and lose with the facts in this case, why should anyone expect that you would not do the same in other cases? How do we know that you will not simply be talking through your hat?
D Boehm says:
As I’ve pointed out ( 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-1126559 ), that is the position of Mann, at least as of his 1999 paper…and I don’t have any reason to believe that he has changed it.
However, it was also his opinion that the Northern hemisphere warmth overall was not as great as in current times and, as I have explained, this seems to be not so much based on any claim that there weren’t areas…maybe even lots of areas…that saw warmth comparable to current warmth sometime during the several hundred year period broadly defined as the MWP. Rather, it is because the warmth in these different regions was not synchronous, which means that when you average over the whole hemisphere, you get a broad, diffuse bump rather than the more dramatic spike we get over the past several decades when most places have warmed with a large degree of synchronicity. This lack of synchronicity was in fact well illustrated by looking at two examples of evidences for the MWP that ColdOldMan linked to: 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-1126537
That is the very site that claims to be refuting Mann’s claim and yet it gives support for Mann’s argument…Go figure!
Leif Svalgaard opines,
“But, for true believers, cheery picking always works their way. One way out is to claim that tree-ring data is nonsense, but that also makes nonsense that there was a ‘decline’ to hide.”
Sorry Leif, it wasn’t us who created a dendro series that had a decline that had to be hidden so the series could be used in alarmist literature. Steve, Anthony and others simply pointed out this sad happenstance. There was a decline in THEIR series and they hid it. Are you becoming a DENIER??
HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA
S. Geiger says:
October 28, 2012 at 6:45 pm
but these types of arguments should consist of facts and dialog, not mere argument by journal association
Few facts and even less dialog have been brought to bear on this [and would have been OT anyway], but the journal issue is important as different journals have different ‘impact factors’ [often related to the quality of their peer-review process – although some will consider peer-review as mere gate keeping], so authors often ‘walk down the list’ until a friendly journal is found. Of course, in this agenda driven discussion, reason falls by the wayside and discussion eventually degenerates into ad-hom attacks, to wit the various remarks about persons’ expertise and bias, etc.
This is excellent new research. Keep in mind that this new work reflects a temperature record for Northern Sweden. Clearly these findings have implications for the results of Mann and Bradley and colleagues, when substituted for the Tornetrask data Mann now uses (as well as fixing the other issues, as Steve McIntyre has so ceaselessly and painstakingly pointed out).
But I wouldn’t go as far as Leif Svalgaard and throw out the solar grand minimum and grand maximum calculations, at least not yet. Because the solar correlations are for temperatures worldwide, not just in Northern Sweden, it seems to me.
davidmhoffer says:
I think that you are making a lot of assumptions here in regards to how significant the Briffa 2012 result turns out to be. At best, it raise some questions about that earlier work; it does not falsify it.
Also, when you refer to the “IPCC conclusion”, you are referring, as near as I can tell, to one sentence of the IPCC report, which reports what Briffa et al. did but does not seem to offer a strong opinion one way or the other as to whether Briffa et al. are likely correct in their notion that this region can tell us a lot about the whole Northern hemisphere temperature record.
ferd berple says:
October 28, 2012 at 6:56 pm
How do we know that you will not simply be talking through your hat?
Because I simply do not do that. A Danish proverb says that “a thief thinks everybody steals”. Perhaps that is applicable to your suggestion.
joeldshore says:
October 28, 2012 at 6:24 pm
Nicola Scafetta says:
By the way, my two accepted papers were refereed by 4 people plus the editor and everybody agreed that the papers had to be published and were free of errors.
That’s pretty impressive. Do they give a money-back guarantee? In the journals that I have published in or refereed for, there are no guarantees given or expected from referees as to whether the papers are free of errors. Certainly, the journals ask one to assess validity as best as one can and to find errors as well as one can but they certainly don’t expect referees to determine definitively if the paper is error-free.
– – – – –
That’s EXACTLY what they are supposed to be expected to determine. Many fields have revision rates one FIFTH that of the climatology religion.
The religion where physicists claim they can’t think of a way to check rise of gas-relevant spectra (heat) in the atmosphere. Thay dont no no waye two.
You’re an intellectual invalid who claims on an international forum for atmospheric and earth based electromagnetic energy,
you don’t believe there’s a way for mankind to check whether there is a rise in gas-specific spectra of LIGHT
in the atmosphere.
And that therefore we must assume there IS, and use a fabrication called ‘precautionary principle’ to dismantle civilization’s infrastructure. No matter what the cost. Because if we don’t install Al Gore’s policies in spite of the election, we could all die.
Jan P Perlwitz says: assorted stuff implying Melvin is not useful whereas Mann is useful.
Come on Jan, neither is representative of global temperatures. Or even Northern Hemisphere temperatures for that matter. Whats the point of saying one is better than the other, especially when the one you prefer was authored by a man who is known to be biased towards confirming AGW.
The Melvin study is another piece in the puzzle. Nothing more. There was a time when AGW believers would argue there were no conflicting papers to AGW but you dont hear that as often anymore do you.
kuhnkat says:
October 28, 2012 at 7:01 pm
There was a decline in THEIR series and they hid it.
The data shown in the paper under discussion does not show a decline, so I don’t know what your point is, if any.
John says:
October 28, 2012 at 7:02 pm
Because the solar correlations are for temperatures worldwide, not just in Northern Sweden, it seems to me.
Yet, people take the temperatures presented for Northern Sweden as confirmation of the global MWP/LIA…
Thank yew perfesser borehole, for that scintillating outlook on sientz and sients refurEEying.
theduke says:
October 28, 2012 at 11:28 am
I can hear Rosanne Rosannadanna now: “Never mind.”
———-
I think that was Emily sombody. Gilda would get on the news with Chevy or Jane and go on a rant then the host would correct her misunderstanding and she’d it.
Can’t remember her last name though and maybe I’m wrong about the whole thing.
Been a long long time.
cn
joelshore says:
“That is the very site that claims to be refuting Mann’s claim and yet it gives support for Mann’s argument…”
Well, the interactive chart certainly doesn’t give very much support to Mann’s position. Most of the items show a global MWP. Not all, but most. I’ve posted that chart at least a half dozen times, and commentators generally agree that it shows a global MWP. It just so happens that you and Mann are not part of the MWP consensus. ☺
But then, you never were part of the true CAGW consensus.
joeldshore says:
October 28, 2012 at 2:46 pm
“It also rather nicely illustrates how that site doesn’t bother to address the real scientific questions and hopes that people who want to believe what they are peddling won’t notice! ”
What your very words illustrate is you take seriously the work of a man who thought he invented a whole field of math along with his colleagues, incorporating statistics so poorly written they were giving up hockey sticks to his colleagues, to people on the internet, and the man who wrote them claims we need to know there could be a catastrophe but that his work’s private so we’ll never know for sure because he might need to make use of that intellectual property in some way of his own, down the road.
What your words illustrate is that you believe there is no way to check for magical properties of a gas in the atmosphere – whether it follows the hockey stuhtistic analysis.
What your words illustrate is that you believe there might be some legitimacy to an operation wherein physicists repeatedly cry in public that they don’t think there’s a way to check for infrared spectra associated with a gas in the atmosphere.
What your words illustrate is you’re a pseudo-science hick.
Posing.
On the internet no less.
Not just in some university somewhere.