IPCC changed viewpoint on the MWP in 2001 – did this have effect on scientific results?
Guest post by Frank Lansner Latest News (hidethedecline)
A brief check indicates a “warm MWP-consensus” before IPCC published the Mann hockey stick graph in 2001. But after 2001, results on MWP seems to approach the IPCC viewpoint.
In April 2009 I collected a series of results concerning Holocene, Historic and recent temperatures for an article on WattsUpWithThat.
Here I found approximately 54 datasets (almost 100% peer reviewed results) that I used for analyzing the claimed difference on MWP on the Northern vs. the Southern hemisphere. I also used the 54 datasets to see if the tree ring method has an impact on MWP results.
Another aspect of MWP results caught my interest:
fig. 1.
It is often debated how IPCC changed its viewpoint concerning the Medieval Warm Period in 2001.
– Was the pre-2001 MWP viewpoint simply “wrong” ?
– When IPCC launched their new viewpoint on MWP in 2001, was this new viewpoint in fact the consensus in 2001?
– Or did the IPCC actually claim to know better than the consensus in 2001?
– What is the consensus on the MWP today?
– And finally, did the results after IPCC change of viewpoint in 2001 have changed, how can this be explained?
Here are the 54 temperature datasets covering the MWP divided in two groups :
1) 1976-2000 vs 2) 2001-2009
fig. 2. (Geographical origin see)
First we see that both 1) and 2) shows the MWP was warmer than today. (This is partly due to my criteria for the 54 datasets: Max 15% tree ring data, due to possible problems with tree ring data and thus a need to see data not dominated by this one method. Quite a few of the excluded tree ring data are frequently used by the IPCC, yielding the well known hockey shapes from IPCC AR4, 2007.)
Second, we see a MWP for group 1) 1976-2000 more than twice as warm, compared to recent years, as the group 2) 2001-2009. A significant and surprising finding. The distance between 1) and the IPCC hockey sticks, with all the tree graphs of recent years, is even bigger.
One might argue that the data choice for my Watts article was not quantitative, fully exact, etc. But I simply cannot come up with any explanation for such a big change in the trend of results when just dividing by the year of publishing. Therefore I will assume that there is in fact a development in the results regarding the MWP after 2001.
Further, if you compare graph 1) 1976-2000 on fig. 2 with the original temperature graph IPCC 1990-2001 on fig.1., you will see a stunning match. This indicates that the consensus of a WARM middle age before year 2001 was likely to be a real consensus. If true:
How could the IPCC publish the hockey stick in 2001 and ignore the consensus at the time?
Several results came later that confirmed the IPCC’s 2001 Opinion: Hockey sticks, mainly tree lines. But how could the IPCC know what the future results on the MWP would be?
If the conclusions of “climate gate” are even remotely true, then this would explain that the IPCC controlled the future results.
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Christopher Hanley (01:49:07)
HH Lamb was certainly aware of climatic data from many parts of the world. What is at issue here is where the data for that graph come from. Steve McIntyre says they are from England – are you going to argue?
“Frank Lansner (06:52:09) :
[…]
So for todays temperatures to be alarmin we need evidense that the SH was VERY cold in the MWP. A SH MCP.
So dont accept cold MWP before we see solid proof for very cold MCP in the SH.”
That’s a very good argument, Frank! It completely destroys the “Local MWP” conjecture!
woodNfish said:
“Who is responsible for that tortured headline? Please use proper English, the dumbed-down ebonics nonsense is disgraceful. (Yeah, I know “dumbed-down ebonics” is redundant.)”
And “dumbed-down” is possibly tautological and ‘dumbed’ isn’t even a “proper English” word. I confess to using the expression, though.
Frank,
I am rather surprised to see your (a bit naive) points from our earlier debates on the Danisch Climate Debate site:
http://www.klimadebat.dk/forum/hide-the-decline-hvad-er-det-reelt-man-daekker-over-d12-e1473-s40.php
being written up as a post here without any further thoughts or references. You appear to think that the IPCC is a body which meets to reach a consensus on a common viewpoint by voting (and not by summarising the research carried out hitherto, as is the case), and you basically ignore every single peer-reviewed paper on multiproxy reconstruction published since MBH98/99.
I honestly think that all your questions can be answered by simply looking at this wikipedia link:
http://en.wikipedia.org/wiki/Description_of_the_Medieval_Warm_Period_and_Little_Ice_Age_in_IPCC_reports
The reason why the IPCC conclusions have changed since 1990 is quite simply that back then, no global multiproxy reconstructions with data from before about 1400 existed – all we had was a few local proxy sets and historical anecdotes primarily from Northern Europe (Norse settlements in Greenland, Medieval Englisch wineyards, ice fairs on the Thames river, Sweden marching over the Baltic sea Ice conquering Scania, Halland and Blekinge from Denmark etc.).
By this, you can conjecture a rough pattern as represented by Lambs 1966 graph: Hot up till about 1400, cold till about 1800 and warming since then. This is your “IPCC 1990-2001” graph, and this is a purely schematic curve – i.e. such data do not allow any kind of quantification. You certainly cannot use Lamb´s graph to claim that the MWP was likely 0,5C warmer than today – and that was definitely not what the IPCC did back in 1990. You should be more careful than jumping to conclusions from schematic graphs.
Here is what my above source has to say about the IPCC 1990-2001 graph:
“A schematic (non-quantitative) curve was used to represent temperature variations over the last 1000 years in chapter 7. The vertical temperature scale was labelled as “Temperature change (°C)” but no numerical labels were given; it could be taken to imply that temperature variations of the MWP and LIA were each of the order of 0.5 °C from the temperature around 1900. The section specifically states recent climate changes were in a range of probably less than 2 °C. The 1990 report noted that it was not clear whether all the fluctuations indicated were truly global (p 202). The graph had no clear source (it resembles figure A9(d) from the 1975 U.S. National Academy of Sciences report, which is sourced to Lamb, 1966), and disappeared from the 1992 supplementary report”.
Now in 2010, with the work of Mann, Smith, Moberg, Briffa, Wahl, Rutherford, von Storch etc. with multiproxy reconstructions in the last 10 years, we know that the MWP and LIA were real phenomena, but nowhere nearly as large as depicted by the old schematic graphs. Consequently, the IPCC has followed suit and incorporated these new results in their reports. Again, IPCC has no independent “will” or mandate to write up other scientific conclusions than those backed by scientific papers.
So, to directly answer your questions in the light of our present knowledge:
1) “Was the pre-2001 MWP viewpoint simply “wrong”?
Well, yes. There certainly was no global MWP 0,5C warmer than today.
2) “- When IPCC launched their new viewpoint on MWP in 2001, was this new viewpoint in fact the consensus in 2001- Or did the IPCC actually claim to know better than the consensus in 2001?”?
The IPCC TAR included all three multiproxy reconstructions available in 2001 (Mann et al. (1999), Jones et al. (1998) and Briffa (2000))- and none of these showed anything remotely like the old schematic 1990 graph.
3) “- What is the consensus on the MWP today”?
It is widely recognised that there was a MWP which was most likely global (though data are stille sparse from the Southern Hemisphere) – also by Michael Mann himself. However, it is equally clear from all reconstuctions that it, in all likelihood, was well below today´s temperatures.
4) “- And finally, did the results after IPCC change of viewpoint in 2001 have changed, how can this be explained”?
English is not my first language either, but I am not sure if that would have helped me understand this question anyway. What exactly are you trying to say?
All IPCC changes has been due to new scientific findings/results having surfaced, if that is what you mean……
Christoffer Bugge Harder (11:28:01) :
When you quote anything by Mann and Briffa you are using discredited sourses.
You need to wake up and realize you’ve been fooled by a hoax.
CBH: Nice to see you read Watts up with that. Then theres hope for you too 🙂
In this context, why not quote Steve McIntyres memorandum for the British Parliament :
http://www.publications.parliament.uk/pa/cm200910/cmselect/cmsctech/memo/climatedata/uc3202.htm
“Summary
1. Reconstructions of temperature over the past 1000 years have been an highly visible part of IPCC presentations to the public. CRU has been extremely influential in IPCC reconstructions through: coauthorship, the use of CRU chronologies, peer review and IPCC participation. To my knowledge, there are no 1000-year reconstructions which are truly “independent” of CRU influence. In my opinion, CRU has manipulated and/or withheld data with an effect on the research record. The manipulation includes (but is not limited to) arbitrary adjustment (“bodging”), cherry picking and deletion of adverse data.
”
Ahhh, this explains how trends pre 2001 from arounf the world appears siginificant different from post 2001 🙂
***********
Me: 1) “Was the pre-2001 MWP viewpoint simply “wrong”?
CBH: Well, yes. There certainly was no global MWP 0,5C warmer than today.
[Oh, is that so? I must have the 54 datasets wrong then, sorry]
ME: 2) “- When IPCC launched their new viewpoint on MWP in 2001, was this new viewpoint in fact the consensus in 2001- Or did the IPCC actually claim to know better than the consensus in 2001?”?
CBH: The IPCC TAR included all three multiproxy reconstructions available in 2001 (Mann et al. (1999), Jones et al. (1998) and Briffa (2000))- and none of these showed anything remotely like the old schematic 1990 graph.
[Oh.. One-tree-Briffa and bristlecone-Mann´s sad work is the only available data in 2001? CBH, Please read the article before commenting]
3) “- What is the consensus on the MWP today”?
It is widely recognised that there was a MWP which was most likely global (though data are stille sparse from the Southern Hemisphere) – also by Michael Mann himself. However, it is equally clear from all reconstuctions that it, in all likelihood, was well below today´s temperatures.
[Oh, again, is that so? So your argument is that I got it all wrong? And I should take that as an “argument”?]
Me: 4) “- And finally, IF the results after IPCC change of viewpoint in 2001 have changed, how can this be explained”?
CBH: All IPCC changes has been due to new scientific findings/results having surfaced, if that is what you mean……
[did this explain why trends of results changed after IPCC changed viewpoint in 2001? Did you read the article?]
An interesting quote from Lamb’s 1977 book “Climate Present, Past, and Future:
“Sea level was also rising again, however, and by around A.D. 400 may have been more than 1 m above the present level.”
“One can point (Bloch 1965) to radiocarbon dated beach and estuary lines in Brazil, Ceylon, Crete, England, the Netherlands, and Palestine which indicate a world-wide (eustatic) sea level high stand at about A.D. 400.”
These quotes are on p. 258, a page inconveniently missing from Google Books version online. Later in the book, on pp. 433-435, he goes on to list the reasons for another high stand during the mwp and says it again reached a high stand about 1 m higher than the present. Sea level had dropped between the rmp and mwp.
Caleb,
oh yes, lest you forget: With every major scientific hoax – the gravity theory, Faraday´s ions, the Archaeopteryx, the moon landing and of course the great Fourier/Tyndall/Arrhenius greenhouse commie plot – you can be sure that I have pretty much swallowed hook, line and sinker. I am this gullible soul who cannot help it.
And of course, it requires a truly gullible soul to accept the conclusions of the bogus whitewashes completely acquitting Mann of the charges of fraud associated with the Hockey Stick research twice (first by the NRC and now by the specially appointed Pennsylvania State University committee) – any clear-headed independent thinker like you intuitively understands that this merely reveals how the conspiracy is even larger than previously believed. There may be no formal evidence for the participation of Moberg, Rutherford, Wahl, Ammann and von Storch yet, but I am sure that it is just a matter of time. And certainly, they must be considered guilty by proxy.
Frankly, there is not much hope for me. I hope that you and your fellow belligerent champions of liberty will show mercy upon me (and other naive victims who failed to see through the sinister forces in time) and fight for our freedom, too, when the UN launches its final attack to impose Christopher Monckton´s eloqeuntly coined “World Communist Government on the World”.
CBH – The PSU inquiry did not address the Mann Hockey Stick. Why did you lie about that? And the NRC did not validate the statistical methods used by the hockey stick, instead finding “Less confidence can be placed in large-scale surface temperature reconstructions for the period from A.D. 900 to 1600. ”
The Wegman report, quick on the heals of the NRC report, then found that McIntyre was correct in his critique of the methods used in the Hockey stick. IN essense, you lied twice. WHy?
Well, Frank,
[Oh, again, is that so? So your argument is that I got it all wrong? And I should take that as an “argument”?]
Yes, it is actually so. You have, indeed, got it all wrong – but your failure to address the points I raised or grasp the basic facts while still being able to maintain a cocksure attitude leaves little hope that anything will ever convince you or move you an inch.
Do you realise that the IPCC 1990-2001 graph is a purely schematic one from which no quantitative conclusions can be drawn? You do not seem to.
You appear to think that the IPCC pre-2001 graph is based on the “1976-2000 proxies” you list? This is not the case. It has no clear source, but is likely Lamb´s 1966 graph (as pointed out by other commenters). How on earth can a 1966 graph be based on some “1976-2000” proxies? And can you enlighten me as to what you mean by this term?
Again, there were no multiproxy analyses before 1997-98, and the IPCC thus had no quantitative estimates of the size of the MWP or the LIA, accordingly. And again, the IPCC do not have a “point of view” independant of the scientific findings.
With respect to your “results” from the 54 datasets, then allow me to ask you a few questions which any reviewer would ask you:
– are any of your 54 proxy sets from a global multiproxy analysis from before 1997/98?
– What measures have you taken to calibrate your proxy series against real temperatures?
– What kind of multivariate method have you used to create your “common factor”, i.e. the trend?
– what have you done to validate your findings (what is the RE/CE-score), and are they statistically significant?
– it normally takes a lot of effort to put different proxies on the same scale and taking noise into account. What are the error bars on your reconstructions?
– your curve shows an increase of at most 0,1C since about 1900. Logically, this implies that all temperature measurements since then are wrong, including the satellites and the SST. How can you make such a claim based on reconstructions? What makes them more reliable than thermometers?
– And yet, you, quite peculiarly, use the single year 1000 as a baseline. Thus, you imply that all reconstructions got the temperature exactly right for this specific year. What on earth is your basis for such an assumption? You appear to reject all the measured temperatures in the last 100+ years, but you have absolute confidence in the reconstructed temperature from 1000 years ago?
– could you provide an entire literature list on the 54 proxies and your justification for selecting precisely those? “Max. 15% tree proxies” appear to be a number pulled directly from the sleeve.
– and just as a curiosity: Your curve shows no decline from 1940-75. Are you trying to “hide the decline”? 😉
I will post this on the Danisch site, too, but I have very little hope that anything will make you realise your misunderstandings.
P.S.: For other sensible readers: Frank is well known in the climate debating community in Denmark. He is a nice guy, no doubt about that, and he clearly believes what he says. However, he is a classical example of an eager amateur who thinks he can refute pretty much all atmospheric physics since Fourier without getting some basics straight. Here is a couple of other outlandish claims from Frank:
– Arrhenius would not have formulated his AGW theory if he had known about the adiabatic lapse rate and the dependence of temperature upon pressure
– The atmospheric CO2 rise is mostly due to outgassing from the sea
– There is an UHI effect of 2,5C
– Tree proxies are more reliable than measured temperatures from 1940 and onwards
– Philip Jones´ phrase “hide the decline” is an attempt to hide the decline in measured temperatures 1940-75.
He has actually managed to establish a whole homepage by the name “hidethedecline.eu” without understanding what the divergence problem is or that Jones´ “hide the decline” refers to this problem (that tree proxies and temperatures diverge from each other from 1960 and onwards).
I guess that most knowledgeable people on this blog will understand what Frank´s problem is.
Jim Clarke,
“To my knowledge, no error found in IPCC documents has ever been an underestimation of danger. All errors inflate the danger”.
Well, you are quite wrong then. Many scientists warned that the estimates of sea level rises of 18-59 cm from the FAR 2007 report were seriously in error – and there is now very little doubt that this is indeed the case.
http://www.realclimate.org/index.php/archives/2010/03/ippc-sealevel-gate/
Furthermore, there are quite many instances of political manipulation in the writing process of the Summary for policymakers where the scientific findings have actually been toned down for political reasons.
http://www.meridian.org.uk/Resources/Global%20Dynamics/IPCC/index.htm
Go figure. Well-documented scientific findings about sea level rise, Arctic sea ice, water vapour feedback and a multitude of other documented feedbacks have been omitted or deleted from the final version as compared to the draft.
Actuallt, quite a few scientists often accuse the IPCC of being
too conservative or suffering from “scientific reticence”, presumably because the organisation does not want to lend itself open to charges of alamism. Obviously, this does not work.
“A reader”
– This is extremely interesting – hmm, is there anyway you can share these pages from Lambs book with us?
K.R. Frank
CBH, you write “You appear to think that the IPCC pre-2001 graph is based on the “1976-2000 proxies” you list?”
No, this is by Lamb, former head of CRU. Its based mostly on English data as I have understood it.
These happend to match the world wide series 1976-2000 representing all continents I collected, and Huangs over 5000 boreholes 1997.
So if you wish to document a “consensus-2001” against these data, you simply have to present for us documentation that is far bigger than this.
If you can do this, then it makes sence to go into further details.
I know weaknesses and strength of the work I did (!), but as long as you can’t even come up with BASIC documentation for your claims(!!!), you have no case.
Frank,
1) Lambs analysis does not match yours. Again: The IPCC graph is purely schematic – this means that you can draw only qualitative and not quantitative conclusions from it.
2) Your analysis is sorely wanting, as I tried to illustrate with my questions. You must have learned some basics about statistics while taking your engineering degree; yet you fail to address the most basic documentation/validation/data selection issues. If you cannot even answer which methods you used or if there is any statistical significance in your results, then your cannot draw any quantitative conclusions from your analysis either. Your analysis would fail any undergraduate exam as you present it here, and it would most certainly be laughed at by any serious journal with a peer reviewing system.
3) Can you point me to any peer reviewed source having analysed your “1976-2000 series” which has found a global pattern as the one you present? I very much doubt that.
And could you, just for at start, point me to the relevant literature for the 54 datasets, so I have a chance to check your selection and analysis with those of the authors you rely upon? I am quite sure that their statistical analysis is much more rigorous (or just existing at all) and is likely to give a quite different picture.
4) Huang´s boreholes do not support your analysis at all. May I hazard a guess that you have obtained your confused interpretation (and maybe your data selection, too?) from this page:
http://joannenova.com.au/2009/12/fraudulent-hockey-sticks-and-hidden-data/
?
See, Pollack and Huang have since retracted their 1997 findings because their deep boreholes showed odd results, such as a LGM of only 1,5C colder than present. They now say that you can count on boreholes only for about the last 500 years, thus making it impossible to make inferences about the MWP, let alone that it be much warmer than present.
Connolley explains it here:
http://scienceblogs.com/stoat/2007/03/the_borehole_mystery.php
If one reads German, then Georg Hoffmann has the best description of the problem that I know of here:
http://www.scienceblogs.de/primaklima/2009/12/das-warme-mittelalterliche-optimum-teil-i-bohrlocher-in-pollockhuangsheng-grl-97.php
Are comments off?
REPLY: No, just you.
CBH: “3) Can you point me to any peer reviewed source having analysed your “1976-2000 series” which has found a global pattern as the one you present? I very much doubt that.”
Dear CBh, in the first lines of the article i link to where the data can be found.
Again, please read the article before commenting.
There are as I remember 15-20 peeeeeeeer reviwed studies i use pre 2001!
Max 25% of these shows a MWP colder than today. And one of the few who shows MWP colder than today is the Vostok series. But this series has around 10 times fewer data points than the other series “South Pole” from Antarctic. So if you want me to go in details, its the Vostok series that would be dismissed and the MWP even stronger in my illustration. And in general there is no way i can massage these data with almost only warm MWP – as you wish – to find anything but a warm MWP.
What you need to come up with is MANY MANY peeeeeer reviewed studies pres 2001 showing COLD MWP!
Its YOU who must proove your case, and Im wating, Send it on klimadebat.dk as it seems you cannot post here.
HUANG: Huang made study of 5000 boreholes 1997 showing warm MWP. Then recently AFTER 2001 he then came up with 600 boreholes showing something else. So HUANG is CONFIRMING that results changed after 2001.
Obviously he says that the 600 is much better quality etc. He has to. So by pure coincidence – again – there was 5000 wrong series and all the errors in 1997 by Huang just happens to produce a homogenuos MWP trend that resembles my 1976-2000 series and the IPCC pre-2001 viewpoint.
And you still havent explained howcome trends can shift after year 2000.
If you wish to carry on, do so in klimmate debate.dk
Mr. Lansner
The Lamb book is still under copyright, but is available at university libraries. The quotes are from Vol. 1.
The Bloch paper Lamb references for the 400 AD high stand is available online, but is behind a paywall. I haven’t read it, so it may be completely refuted somewhere. Its title is “A hypothesis for the change of ocean levels depending on the albido of polar icecaps” in Paleogeography, Paleoclimatology, Paleoecology 1. 127-42.
“HUANG: Huang made study of 5000 boreholes 1997 showing warm MWP. Then recently AFTER 2001 he then came up with 600 boreholes showing something else. So HUANG is CONFIRMING that results changed after 2001”.
Sorry, but you have quite simply completely misunderstood this. Try reading your sources for a start.
First of all, Pollack and Huang revised their work already in 1998:
http://www-personal.umich.edu/~shaopeng/science98.pdf
– and in 2000:
http://www-personal.umich.edu/~shaopeng/annurev00.pdf
That would be before 2001, right? 😉
And no, they did not come up with 600 new holes showing something else – actually, their later work only went back 500 years, thus telling us nothing about the Medieval times at all. Rather, in their later work they focused on holes up to about 400 m in depth, because they were of better quality (i.e. gave a better resolution). And actually, their 1997 paper contained no information at all about the temperatures of the 20th century because they excluded the upper 100 m from analysis altogether!
Huang and Pollack published a paper in 2008 explaining the difference between their 1997 and their 1998/2000 work:
http://www.geo.lsa.umich.edu/~shaopeng/2008GL034187.pdf
Indeed, they quite clearly state
“the results of HPS97 [their 1997 paper as quoted by you, CBH] cannot be used for comparing MWP warmth to the 20th century”.
Their 2008 paper combines their 1997 low resolution and the 2000 high resolution work to look at the last 20.000 years, and guess what they find? -: A nice warm MWP, a nice cold LIA, and a nice modern warming about 0,5C warmer than the MWP. (Look at their Fig. 2.)
So you see, there are a couple of grave anachronistic holes in your nice little conspiracy theory. And you are using their 1997 results exactly in the way which the authors themselves have explicitly denounced. Do you begin to understand why I am not impressed? 🙂
“Dear CBh, in the first lines of the article i link to where the data can be found.
Again, please read the article before commenting.
There are as I remember 15-20 peeeeeeeer reviwed studies i use pre 2001!”
You do not appear to understand what I asked you. I have seen your previous post and your sheet with the origin of your sets, and they appear to be all local proxies. What I was asking you were if there existed any global multiproxy analyses pre 2001 finding an MWP much warmer than the late 20th century? As written above, Huang 1997 is not going to help you.
And just to be clear: It is actually you who need to make a case. We already have scientific multiproxy analyses both with and without tree rings which have found the present times to be warmer than the MWP. Mann himself did this analysis in his 2008 paper in PNAS, as I thought you knew?
http://www.pnas.org/content/early/2008/09/02/0805721105.abstract
These and the other multiproxy reconstructions from peer reviewed sources all address the obvious questions I presented for you above (data selection, validation, filtering, reference period).
You want to prove the entire climate science wrong. Thus, it is actually YOU who have a case to prove – quite an extraordinary one, in fact. And you know that extraordinary claims require extraordinary proofs, right?
From what can be deciphered from your rather untidy Excel graphs and brief presentation, it appears as if you have simply chosen some random proxy sets and taken an aritmetic average with one single year (1000) as a baseline. No statistics, no filtering, no arguments for or justification of your data selection or baseline.
This may impress people like “Caleb” who are already convinced that it is all a big hoax (like the moon landing or the evolution theory?). But if you want to convince anybody who knows about the requirements for scientific documentation about the MWP being warmer than present, you really need to do better than this.
Take this as a kind advice.
Correction to my comment above. The quotes from the Lamb book are from Vol. 2.
CBH: Ahhh… I just took a simple mean of data, but i should have done like Mann? This I understand, heres how Mann comes from a simple mean to his “processed” data:
http://www.klimadebat.dk/forum/vedhaeftninger/mannaverage.jpg
And surely, if MANN can come from only 2 tree line series (Bristlecones, Rocky Mountain etc) that is, a complete minority of data showing a hockey stick, then it shold be possible for ME to?
Perhaps you are right. I my case I have around 20-25% of the data not showing MWP warmer than today. Compared to Manns original data it must be possible to do something to get a cold MWP out of data.
And when Mann uses a Hockey stick signal from the Rocky mountains, and weights this data up to 200-400 times more than other seires, then he can actually call it Bristlecone series for “Northern Hemisphere”? 🙂
And then, ladies and gentlemen, it is correct of the IPCC to ignore all the evidence from the other scientists. Mann called his result for “NH” – then results from “sinlge points” all over the rest of the globe doesn’t matter.
The thing is, CBH, when only a small fraction of data shows cold MWP, and you still want to process data to get the result “cold MWP”, then the IPCC sould employ you – you have the right spirit for seeking the truth 🙂
– Another thing, CBH.
IF its true what you say, that Huangs huge change in results from warm MWP to cold MWP came just before 2001, i dont think it changes my point much. The stiff dividing point i used “2001”, is not perfect. Manns work was dicussed in the climate gate emails before 2001, so what matters is, that results goes from contradicting IPCC to more often agree with IPCC.
This goes for Huang too, even though it took place earlier than 2001 – assuming that you are correct.
How do you feel about the Mann 2008 where xray-trends where turned upside down? how do you feel about the Finnish scientist incl. Korhola, that cannot recognice Manns postulated “warming” from their kottajärvi data? I can tell you that they are stunned how Mann can twist their data.
And finally: Since the data from my article happens to by spread out on the globe rather fine, it wont change much to weight the exact areas. i can guarantee 100% that any TRUE filter will or averaging or weightin will never ever produce what you and IPCC want to see. If you take a good looke at the graphs you will se a big variability in data. We have to be realistic, there is a lot of noice in data (!) making fine tuning as you suggest a little overkill.
IF for example data showing warm MWP was allmost all from one region then it would make a siginficant difference to weight data.
Compared to Manns HUGE fokus on just a few datasets from the Rocky mountains, US, my simple average where all continents are represented is honesly much much better. Not rocket science, but much better than Mann.
If you, CBH, actually seeks the truth (i hope) then you would go after Manns methods with the exact same energy as you go after my data.
Can you explain why Mann overfokus on Bristlecones, one area of the NH and then claims results to be NH?
Can you explain why hia computerprogram was made to output hockey stick almost never mind what real data was used as input?
Can you explain why Briffa claims that Sibieria too had a temperature hockey stick just from a few individual trees?
No you cant. If you seek the truth you will stop for a moment and wonder how Mann + Briffa does “science” and thus IPCC who use it again and again.
And Frank, with respect to “going after Mann like after you”:
I am actually holding you to exactly the same standard as Mann and the coworkers. You clearly fail to understand what I am saying.
“CBH: Ahhh… I just took a simple mean of data, but i should have done like Mann? This I understand, heres how Mann comes from a simple mean to his “processed” data……”
No. What you should do is
a) choose an appropriate multivariate method
b) make sure that your data are calibrated and put on a common scale.
c) make appropriate tests to filter signal from noise
d) conduct a test of some kind to validate your reconstruction like e.g. RE (reduction of error) scores
e) calculate some error bars or at least some other kind of confidence intervals to tell us something about how certain we can be of your findings.
These are the objective criteria any neutral observer should demand from anybody trying to make a case about past temperatures. Mann, Jones, Osborn, Briffa, Moberg, von Storch etc. have all met this. If you can point me to anything about the proxy record in the recent IPCC reports which fail to meet these standards, I shall be happy to denounce it.
You do not need to carry a)-e) out exactly like Mann did in 1998. E.g., there are several types of PCA (principal component analysis) or other multivariate methods you could use, and you are free to choose a different reference period than 1901-1980. But you do need to meet the a)-e), the most basic requirements of statistical analysis of proxy reconstructions. Craig Loehle failed on a), d) and e) in his original attempt. Actually, the first schematic IPCC 1990 graph also failed here. And you, so far, fail miserably on all five counts. This is why nobody knowledgeable in the field would take the IPCC 1990 graph, Loehle or you seriously today.
– How are we to know whether anything in your “work” is significant? Please do some calculations. Come on, Frank – you do know that the issue of statistical significance is quite important, right? Without this, we have no way of knowing whether any of your results are due to pure chance. It is not enough that they appear visually impressive to you, sorry.
– You yourself have often gone on and on about the uncertainty in the modern directly measured temperature record. But here, you are suddenly absolutely sure that your 54 proxies got everything completely right for the specific year 1000? Do you honestly fail to see the blatant inconsistency?
– What is the basis for your 54 proxy selection? Most other multiproxy reconstructions contain 4-500 proxies and openly admit to still be missing coverage on the Southern Hemisphere and that this may affect the results – and they often bend over backwards to test different methods or datasets. Yet you, Frank Lansner, who by your own admission are employed as a “semi-amateur rock musician”, are so cocksure that you do not need any documentation when issuing “guarantees of a 100%” (is that correct English?) that everything is absolutely fine with your selection and that your prep school arithmetics completely void of any statistics is much better than statistically validated work of professionals published in Nature and Proceedings of the National Academy of Science? Do you honestly believe that any neutral observer would not find you less than convincing?
If you repeat your analysis while taking appropriate care of the above points. then I will begin taking you seriously. I hope you can see that I demand nothing more, nothing less from you than I do from Mann, Briffa or anyone else.
And with respect to the specifics about Mann´s methods:
McIntyre and McKitrick´s original critique (which you repeat) about the non-centered PCA and the 1901-80 normalisation yielding hockey sticks out of red noise was a serious scientific critique, but is has been shown not to matter at all for the outcome by later research: Rutherford et al. showed that a non-PCA analysis yielded the same results, and Wahl and Ammann showed that a nomalisation with the 1854-1901 epoch instead of 1901-80 made no difference either. I have shown you these papers before, but I will be happy to look them up for you again – if you promise that you are actually going to make an attempt at reading them this time.
And with respect to the validity of tree rings: Are you aware that Mann et al. carried out the analysis in their 2008 paper both with and without tree rings – and found the same pattern in both cases (albeit more markedly with the tree rings included)?
With respect to the Tiljander proxy and the upside down issues, then Mann et al. replied to McIntyre and McKitrick: that:
“The claim that ‘‘upside down’’ data were used is bizarre.
Multivariate regression methods are insensitive to the sign of
predictors. Screening, when used, employed one-sided tests
only when a definite sign could be a priori reasoned on physi-
cal grounds. Potential nonclimatic inf luences on the Tiljander
and other prox ies were discussed in the SI, which showed that none of our central conclusions relied on their use”.
From what I know it is certainly true that multivariate regression methods should not be sensitive to the sign of the predictors, but I admit that the details of the one-sided testings and definite signs are over my head. But if Atte Korhola is unsatisfied with the treatment, then he is free to make his own analysis and show Mann et al. to be wrong. This is how science progresses. He is a real scientist and should be perfectly able to do this. However, making outlandish allegations about fraud and erroneous analysis in public while failing to face the critique head-on in scientific venues in not impressive. It is the classic bragging of someone on a pub assuring his mates that he can knock down any heavyweight champion, and yet shuning away from the boxing ring when challenged. It is in science pretty much like in boxing: “Put up or shut up”.
P.S. With respect to Huang and Pollack, I am quite baffled by your non-answers. First, you claimed that Huang exactly confirmed your thesis about the post 2001 change, and now when it does not, it does not matter because…..there were e-mail correspondence between the CRU scientists and Mann before 2000? Or what? You appear to have got it all backwards: The reason why the IPCC report has changed is because the science has evolved – not the other way round.
Second, Huang did not show a “huge change from warm to cold MWP” in comparison to the present. Again, their 1997 results contained nothing about the 20th century because they quite simply cut off their analyses in 1900. And adversely, their 2000 analysis contained no information before 1400 and thus tells us nothing about the MWP at all. Huang and Pollack did not and still do not contradict anything in the IPCC reports. Their combined analysis of the two from their 2008 paper shows pretty much the same as all other rconstructions – warm Medieval times, cold LIA and an even warmer present.
Why do not you try reading the Huang papers for a beginning instead of going on relentlessly about what you conjecture they could have been saying? I have provided copious links, in case you have not noticed. If you think that I am hoodwinking you, then why do not you go figure for yourself?