This is a continuation of a remarkable thread that has now received 10,000 comments running to well over a million words. Unfortunately its size has become a problem and this is the reason for the move.
The history of the New Statesman thread goes back to December 2007 when Dr David Whitehouse wrote a very influential article for that publication posing the question Has Global Warming Stopped? Later, Mark Lynas, the magazine’s environment correspondent, wrote a furious reply, Has Global Warming Really Stopped?
By the time the New Statesman closed the blogs associated with these articles they had received just over 3000 comments, many from people who had become regular contributors to a wide-ranging discussion of the evidence for anthropogenic climate change, its implications for public policy and the economy. At that stage I provided a new home for the discussion at Harmless Sky.
Comments are now closed on the old thread. If you want to refer to comments there then it is easy to do so by left-clicking on the comment number, selecting ‘Copy Link Location’ and then setting up a link in the normal way.
Here’s to the next 10,000 comments.
Useful links:
Dr David Whitehouse’s article can be found here with 1289 comments.
Mark Lynas’ attempted refutation can be found here with 1715 comments.
The original Continuation of the New Statesman Whitehouse/Lynas blogs thread is here with 10,000 comments.
TonyB,
You seem to know more than me about Hubert Lamb. Maybe you could spare a few words of wisdom regarding his “tilting of the circumpolar vortex theory” in connection with the MWP?
Now it seems to me that if the Vortex tilts one way the North Atlantic would get warmer (MWP) and the North Pacific would get colder. And if it tilted the other way then vice versa. A colder NA (LIA) and warmer NP.
Now it’s possible that Lamb’s tilting vortex theory is incorrect. But nevertheless, as theories go, it sounds reasonable enough, and it was obviously what Lamb thought or otherwise he wouldn’t have suggested it. Would he?
I’m still not quite clear, how Lamb could have suggested this mechanism, and believed that if it tilted one way the Earth warmed overall (MWP) or, if it tilted the other way, it cooled overall (LIA)
Can you explain?
PeterM
You are again “beating a dead dog” with your “it seems to me” arguments about Lamb.
Tony may have something else to add, but here is my advice:
Read Lamb’s studies.
There is no question that some of his hypotheses on tilting axes, etc. may not have stood the test of time, but his exhaustive work on climate trends in Europe, North America, Greenland plus a few other locations in less detail have.
These data can be “filled in” by other more recent studies covering the geographical regions, which Lamb did not study in detail.
These studies exist, as well, and have been cited.
Read what’s out there, Peter, rather than trying to “niggle” in order to try to “prove” that Lamb specifically concluded that the MWP and LIA were not global events.
I cannot find anywhere that he specifically wrote this, but even if he did, he obviously could not been aware of the many studies from all over the world showing a warmer MWP, because these were published after his work.
Give up on your silly line of argument and read all the many reports out there instead.
Max
PeterM
You berate Brute (1325) for citing WUWT regarding the McShane and Wyner statistical re-analysis of Mann’s raw data, rather than giving the link to the original study.
This link is right there, for anyone who isn’t blind to see, but I will post it here for you, so that you can read the full study in detail.
http://wattsupwiththat.files.wordpress.com/2010/08/mcshane-and-wyner-2010.pdf
It is clearly stated that the difference between Mann et al. and this study is NOT in the raw data, but in the statistical approach used to evaluate this raw data.
Among the conclusions we read:
A pretty clear conclusion – almost as clear as that of Wegman, when he stated:
Mann apparently used a faulty approach, which creates a hockey stick artifact even with random data (as was reported in a statistical reanalysis of his study by McIntyre and McKitrick, reiterated by the Wegman committee and confirmed before US Congress by North and Bloomfield).
The M+W study is made by two individuals who are statistical experts and, therefore, quite logically understand statistics a bit better than Mann’s team. As they have concluded, there is no evidence for a “hockey stick”.
It’s just one more scientific falsification of the Mann et al. hockey stick.
I suggest that you read the detailed scientific report rather than berating Brute for having found it on WUWT.
Max
PeterM
You are not following your own advice which you gave to Brute:
That is good advice, Peter.
Now here is my advice to you:
Max
PeterM
Your sentence below (1320) is so silly and childish that it really does not merit a reply:
Let me clear it up for you, Peter (Brute may have other thoughts, but these are mine).
I can accept past figures by these groups with a “small grain of salt”, because I know how easily data can be manipulated to “prove a point”.
But crystal ball forecasts of future disasters?
These are a bit harder to swallow, inasmuch as these guys basically do not know any more about the future than anyone else, have demonstrated a lousy forecasting record in the past and are trying to “sell” us a preconceived “doomsday scenario” of (future) scorching temperatures plus rapidly melting ice and rising sea levels, which will inundate us all.
These guys should all limit their reporting to past actual figures (which I “can accept”) and leave out all the sensationalist hype about future disaster (which I “cannot accept”).
Hope this clears up your point.
Max
Max,
Yes you are right that there are better places to reference from that Wattsupwiththat. But I guess there are worse too like the “American Thinker”! That’s just a joke. So maybe Brute should be commended to a limited extent if he chooses WUWT.
My #1325 wasn’t about McShane and Wyner in any case. So, I think you’ve got hold of the wrong end of the stick there, mate!
TonyB,
I think that Max must think you are in a bit of trouble with my question. But it is just that – a question? That’s what science is about, asking questions.
I honestly don’t understand how Lamb’s tilt mechanism works in the way you suggest and I’m asking for a clarification.
I hope you can do a bit better than tell me to read Lambs book again!
PeterM
You are confusing me.
In 1325 you wrote (apparently referring to the McShane & Wyner statistical re-analysis of the Mann data):
In 1331 you wrote:
So which post is correct?
Just curious.
Max
PeterM
You (1332) are apparently fascinated by a brief mention by Lamb of a possible “asymmetry of medieval warmth over the northern hemisphere”, which may have been caused by “a persistent tilt of the whole circumpolar vortex (and the climatic zones which it defines) away from the Atlantic and toward the Pacific sector”.
It is an interesting postulation, but let’s look at it more closely.
Lamb writes (Climate, History and the Modern World, p.171)
Out of a detailed study covering hundreds of pages concentrating primarily on Northern Europe and the Northern Atlantic, there just is not much discussion of Asia during the MWP, except for this brief paragraph of the observed “asymmetry”.
Lamb points out that, based on his limited data, it appears that the medieval warmth in China and Japan peaked in the ninth century, and was followed by a colder period lasting two to three hundred years (1000-1300). From these data, Lamb postulated that, if this is so,
Since Lamb’s book was written, there has been a considerable amount of new data on the climate in China, the Indo-Pacific Ocean, Siberia and Japan during the middle ages, which was, obviously, not available to Lamb. These data point to a warmer period, which lasted far longer than indicated by Lamb’s earlier, more limited, data.
Here are some specific examples (bold emphasis by me):
De’Er Zhang, Earth and Environmental Science, Climatic Change, Vol.26, Nos. 2-3, 289-297 DOI: 10.1007/BF01092419, Evidence for the existence of the medieval warm period in China,
http://www.springerlink.com/content/gh98230822m7g01l/
Ge, Q., Zheng, J., Fang, X., Man, Z., Zhang, X., Zhang, P. and Wang, W.-C. 2003. Winter half-year temperature reconstruction for the middle and lower reaches of the Yellow River and Yangtze River, China, during the past 2000 years. The Holocene 13: 933-940.
Honghan, Z. and Baolin, H. 1996. Geological records of Antarctic ice retreat and sea-level changes on the northern bank of the Shenzhen Bay. Tropical Sea 4: 1-7.
Zicheng, P., Xuexian, H., Xiaozhong, L., Jianfeng, H., Guijian, L. and Baofu, N. 2003. Thermal ionization mass spectrometry (TIMS)-U-series ages of corals from the South China Sea and Holocene high sea level. Chinese Journal of Geochemistry 22: 133-139
In addition to these studies covering China, there are also recent studies covering Japan:
Adhikari, D.P. and Kumon, F. 2001. Climatic changes during the past 1300 years as deduced from the sediments of Lake Nakatsuna, central Japan. Limnology 2: 157-168.
Kitagawa, H. and Matsumoto, E. 1995. Climatic implications of ?13C variations in a Japanese cedar (Cryptomeria japonica) during the last two millennia. Geophysical Research Letters 22: 2155-2158.
One study covers the Indo-Pacific ocean:
Newton, A, Thunell, R. and Stott, L.
“Climate and hydrographic variability in the Indo-Pacific Warm Pool during the last millennium”, GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L19710, doi:10.1029/2006GL027234, 2006
http://earth.usc.edu/~stott/stott%20papers/Newton%20et%20al.,%202006.pdf
Another Asian study covers Siberia:
Kalugin, I., Daryin, A., Smolyaninova, L., Andreev, A., Diekmann, B. and Khlystov, O. 2007. 800-yr-long records of annual air temperature and precipitation over southern Siberia inferred from Teletskoye Lake sediments. Quaternary Research 67: 400-410.
So it appears clear that independent studies using different methods and records, which have been published after Lamb’s studies, reveal that the period AD 1100-1300 “cannot be considered a cold period, as previously believed”.
With these new data in mind, it is hardly necessary to attempt to validate Lamb’s hypothesis of
This hypothesis has already been falsified by the data, which do not show a cold period in Asia during the period from AD 1000-1300.
Since there was no cold period in Asia during the latter MWP in Europe (AD 1000-1300), there is no need for a persistent tilt of the circumpolar vortex as a postulated explanation for such a cold period.
That would be my analysis of the situation. TonyB may have another.
Hope this answers your question, Peter
Max
Max,
They both are correct.
I know that M&W have objected to Mann’s treatment of his data but they aren’t the first and , no doubt, given the amount of firepower that is directed towards Mann, they won’t be the last. So my comment wasn’t so much about M&W, but rather about whether Mann treated his data correctly.
I don’t think I’m stupid enough to say that he didn’t on the basis of one objection. I’m not a statistical expert by any means, and I can honestly say that I really don’t know if there are any flaws in Mann’s methodology.
I’m sure that yourself and Brute haven’t got the slightest clue between you either! Which is why you both need a bit of advice of keeping quiet unless you know what you are talking about.
Lets just see how the story unfolds.
Max,
You may be right in that there is “no need for a persistent tilt of the circumpolar vortex as a postulated explanation for such a cold period.”
Nevertheless, need or no need, that is what Lamb indeed did postulate. As I have already written, maybe Lamb was indeed wrong in his tilt theory.
I’m still asking for an explanation of how Lamb could have thought that the tilt theory was correct and still believed that the MWP was global rather than regional.
PeterM
Here is the link to Lamb’s book (p.171), posted separately to avoid problems with spam filter.
http://sites.google.com/site/medievalwarmperiod/_/rsrc/1236897691015/Home/p171–172-of-lamb-s-climate-history-the-modern-world/P171_172-CMW.gif
Max
PeterM
I’m afraid that I cannot answer your hypothetical question
But, despite the fact that this is a rather convoluted question of a hypothetical situation, I will try
Lamb had limited data on the MWP in Asia.
This limited data indicated that the MWP had peaked there in the 9th century, and was followed by a cooler period from around AD 1000 to 1300 (while it lasted until 1300 in Europe).
From this Lamb concluded that there must have been an “asymmetry” between Europe-Atlantic-Greenland-North America and Asia and that the MWP did not overlap directly between Asia and the primary geographical region of his study).
He postulated that if this is so it could have been partly explained by a persistent tilt of the circumpolar vortex away from the Atlantic and towards the Pacific.
[Note Lamb’s caveats: “if so” and “part of the explanation”]
Since Lamb’s study there has been a lot of data showing that there was no cold period in Asia between 1000 and 1300, as had been previously believed.
Therefore there was no “asymmetry” between Asia and Europe, as Lamb had postulated.
Therefore his postulated explanation of a persistent tilt in the circumpolar vortex as a possible cause for an “asymmetry” has been falsified by the facts on the ground.
Lamb simply did not have all the data on Asia, which is available today, during his time.
Based on the limited data he had, he obviously believed (erroneously as it turns out) that the MWP in Europe and Asia did not overlap, and that there was a period from around 1000 to 1300 when it had already cooled in Asia but was still warmer than normal in Europe.
This in no way detracts from the pioneering job he did in exhaustively assembling and analyzing the voluminous data he had for Europe, the Atlantic, North America and Greenland in establishing a MWP there that was warmer than today.
Got it?
Max
PeterM
You are apparently not paying attention to posts you receive.
You write that Mann’s statistical approach should not be invalidated just “on the basis of one objection”.
There were three objections to date, Peter, as you know full well if you have been reading your posts and the cited attachments:
First, McIntyre and McKitrick showed in a detailed statistical analysis that Mann had used “cherry picked” data and an analytical approach skewed to producing a “hockey stick”.
Second, the US congressional committee investigating this matter requested a statistical analysis by a panel led by one of the top US statisticians, Carl Wegman. This panel validated the M+M objections and concluded that Mann’s study was statistically flawed (and that his conclusion of an unusually warm 20th century “cannot be supported by his study”).
In later testimony before the congressional committee, North and Bloomfield (both of NAS) confirmed the conclusions reached by Wegman.
Now we’ve got the statistical analysis by McShane & Wyner using Mann’s original data, which comes to the same conclusion on his flawed approach using yet another statistical analysis.
So Mann’s hockey stick has not been invalidated “on the basis of one objection”. I can see three separate studies by statistical experts (which Mann’s team clearly were not) plus a confirmation by a NAS panel that falsify Mann’s hockey stick.
Look, Peter, if you want to “believe” in Mann’s hockey stick, Santa Claus or the Easter Bunny, that’s your privilege.
But don’t make up stuff that is not true in order to try to support your “belief”.
You are beginning to sound like a religious fundamentalist trying to support his belief in “creationism”, despite all the data out there, which falsify this “belief”.
Max
Top Climate Scientists Speak out on the Satellitegate Scandal
http://canadafreepress.com/index.php/article/26603
Just curious………why doesn’t the UK just finance the economic shortfalls with all of the “green job” tax revenues that have been pouring into the coffers?
Plan to sell off nature reserves risks ‘austerity countryside’
http://www.guardian.co.uk/politics/2010/aug/13/plan-sell-nature-reserves-austerity-countryside?showallcomments=true#start-of-comments
Looks like the Met Office will have to fend for itself also………
UK Government May Sell Off Met Office, Nature Reserves
I love fossil fuels……..
Britain puts decarbonisation on hold
http://www.guardian.co.uk/environment/2010/aug/15/coal-fired-power-stations-coalition
Max,
You need to distinguish between MBH199
http://www.ltrr.arizona.edu/webhome/aprilc/data/my%20stuff/MBH1999.pdf.
and Michael Mann’s later publications including this one:
http://www.pnas.org/content/early/2008/09/02/0805721105.abstract
At least as far as I’m aware, the early barrage of attacks concentrated on the 1999 paper, but M&W are the first ones to raise serious objections to the 2008 update.
But you probably keep a sharper eye out than I do for this sort of thing, and if there have been any others, I’d be interested to see what they have to say.
TonyB,
How’s your explanation of Lamb’s tilt theory coming along?
Max,
I don’t think you are correct about the NAS. For example there is this Nature reference to:
“Academy affirms hockey-stick graph”.
http://www.nature.com/nature/journal/v441/n7097/full/4411032a.html.
In addition there are many other hockey stick type graphs using bore hole temperatures, information from glaciers and the ice core record. Its not all about tree rings.
http://www.realclimate.org/index.php/archives/2008/09/progress-in-millennial-reconstructions/
But I am intrigued by your continued assertions that Mann has been discredited by the NAS and mainstream science generally. If you have any proper scientific references to show that his work has been invalidated I’d be pleased to see them.
Max,
You say “I’m afraid that I cannot answer your hypothetical question” on how Lamb could have thought that the tilt theory was correct and still believed that the MWP was global rather than regional.
The reason you can’t answer is not because its hypothetical, but because Lamb’s “tilt theory”, whether correct or incorrect, is incompatible with the existence of a Global MWP but totally compatible with a regional MWP
So you need to be a lot more careful than TonyB in claiming Lamb as one of your own! Some of his theories are quite inconvenient for you!
PeterM
There you go, yet once again, with silly statements.
No one is “claiming Lamb as one of your own”.
He has written a pioneering study. This is not “Holy Scripture” that conveys “absolute or divine truth”. It is a study that tells us much about our planet’s past climate, in particular as it relates to the geographical regions for which Lamb had data at the time.
It is clear from Lamb’s exhaustive work that he has established several climate swings that caused major changes to human civilization, from Roman times through the Dark Ages, the Medieval Warm Period and later Little Ice Age, from which we have (fortunately!) been gradually recovering since the modern temperature record began.
Lamb’s data were largely restricted to Europe, North America, the Atlantic and Greenland. Using the CET record plus extensive historical records, he makes a good case for a MWP that was slightly warmer than today in the regions for which he had data. His study concludes that this MWP lasted until around 1300.
In a single page of his lengthy study he briefly mentions Asia, where his data are much more sketchy (relying essentially on one source). Based on this limited data he concludes that the medieval warmth peaked earlier there, around AD 900.
From these conclusions he postulates the “tilt theory”.
Since then, there have been many studies on Asian climate during the period 1000-1300, using records plus different proxy methods.
These clearly show that the MWP overlapped fairly closely in time in Asia with the region studied by Lamb, thereby lending support to the premise of a global MWP (at least in the Northern Hemisphere).
This falsifies the premise upon which his “tilt postulation” was based.
That’s all, Peter.
In addition, other studies from locations in the Southern Hemisphere (which I have cited) demonstrate that the extent of the MWP very likely was global, covering both hemispheres.
We have discussed this point ad nauseam. If you are trying to say “Lamb tells us the MWP was not global, therefore it cannot be”, that would be silly, indeed.
Lamb simply did not have all the data that are available today on climate in Asia during this period, so his conjectures on a “tilt” theory to explain a phenomenon that has been shown not to have existed have become outdated and irrelevant.
Lack of evidence of an event is not equal to evidence for the lack of this event.
Let’s break this off, Peter. It’s getting repetitive and going nowhere.
Max
PeterM
You are “in a hole” in your feeble attempt to breathe life back into the discredited Mann hockey stick.
My advice: “stop digging”.
Neither of your cited links help you very much in your resuscitation attempt, Peter:
The link to (Michael Mann/Gavin Schmidt’s) RealClimate site does not mention an NAS endorsement.
The second (NAS) link has nothing at all to do with Mann’s hockey stick.
I have cited the scientific (statistical) study by McIntyre and McKitrick that first pointed to statistical flaws in the hockey stick.
Then there was the report of the Wegman panel to the US congressional committee, which endorsed the conclusions of the M+M study, establishing that the statistical approach of Mann was incorrect, and concluded:
This is as comprehensive a scientific discreditation of the hockey stick as one can imagine and, in addition, it directly refutes the IPCC claim that the “warmth of the last half century is unusual in at least the previous 1,300 years”.
When specifically asked under oath whether they supported the conclusion of the Wegman panel, both North and Bloomfield (of the NAS panel) specifically answered that they did.
So two distinguished NAS members, one a climatologist and the other a statistician, both agreed with the conclusion of the Wegman panel that the Mann hockey stick was based on a faulty statistical analysis and that Mann’s conclusion (and, by extension, the IPCC claim) of unusual late 20th century warmth cannot be supported by his study.
Supporters of the “hockey stick” tried later to use the argument that, while there may have been errors in the methodology used by Mann et al., the conclusions reached were still correct.
As Wegman summed it up to the energy and commerce committee in later testimony:
Peter, let’s truly forget about this piece of “Bad Science” and whether or not the political leadership of NAS later tried to save someone’s face by endorsing it. This really does not matter. As I have demonstrated to you (with references), it has been scientifically (statistically) invalidated (the latest scientific report is just another “nail in the coffin”) and officially discredited by a panel of statistical experts under oath before a congressional committee, with two NAS members officially endorsing the conclusions reached before this committee.
Let it R.I.P.
Max
Peter
It is quite clear you have never read Lambs books but merely skimmed them electronically in order to make some mischievous point or other.
Lamb wrote exclusively before the age of the internet. This had great advantages and some disadvantages. The advantages are that when he researched something it was done in a thorough manner as he had to follow up numerous individual points of enquiry, often over a period of years. He would also talk to other experts and the end result is a meticulous body of work based on the evidence of the time.
The disadvantage is that there was not the instantaneous flow of information you get these days (not always of a high quality or considered in context and at length).
It was evident that Lamd was particularly interested in the jet stream, and had he lived another twenty years I dare say he would have devoted more time to this still relatively unknown- but apparently powerful driver of our climate. Then, considered together with the recent knowledge of the extent of the MWP, he may have advanced a different theory than the one you are beating to death.
I previously posted this;
http://www.newscientist.com/article/mg20727730.101-frozen-jet-stream-leads-to-flood-fire-and-famine.html?DCMP=OTC-rss&nsref=online-news
It appears that the jet stream gets ‘stuck’ in various positions for many decades. For example those areas that are curently getting deluged in the ‘unprecedented’ monsoon rain used to have much more severe events hundreds of years ago when the jet stream was commonly in a different position.
Since Lambs death there have been numerous studies on the mwp, some of which Max has referred to, but which you airily dismissed without reading.
I would not endorse every single study carried by CO2 science but the overwhelming majority are as they say. http://www.co2science.org/data/mwp/description.php
Go to ‘study descriptions and results.’ It is clear there was a global overlapping MWP but many of the studies have only become known since Lambs death. As he was dead he was therefore unfortunately unable to write about them.
I have referred you continually to what were practicaly Lambs last written words on what his beliefs were, but you seem to wilfully ignore them.
Do these sound like the words of someone who believes implictly in CAGW?
“The idea of climate change has at last taken on with the public after generations which assumed that climate could be taken as constant. But it is easy to notice the common assumption that mans science and modern industry and technology are now so powerful that any change of climate or the environnment must be due to us. It is good for us to be more alert and responsible in our treatment of the environment, but not to have a distorted view of our own importance. Above all, we need more knowledge, education and understanding in these matters.”
Lamb and Mann are completely different breeds of scientists and I don’t know why you have attempted to align their views or conflate their studies.
Read the MWP studies Peter, read some more Lamb (he wrote many books) look at the way in which global temperatures are calculated. Consider the effects of UHI on an increasingly urbanised database and the effects of moving stations from one location to another. Look at the extremely modest rise in temperatures over many hundreds of years as evidenced in CET,Debilt, Uppsala etc etc which predate enhanced CO2, as does the MWP.
Then p[lease try to put the modern warm period ino a better historic context.
It will also help if you suspend your touching belief that everything that comes out of the worlds climate institutions is anywhere near as scientifically based as you believe-our knowledge of climate is still in the dark ages despite the belief of some who think we already have all the answers.
As Max says, this particular conversation is going nowhere so I would be interested in the opinion of both yourself and Max on one such respected global temperature database. Perhaps you would both like to comment on the accuracy of Sea surface temperatures (SST) to 1850 as used by such as Hadley as a crucial part of the IPCC ‘evidence’.
tonyb
TonyB
I’ve asked you for a simple explanation of Lamb’s “tilting circumpolar vortex” theory.
Max is unable to give a satisfactory explanation. You’re unable to give any explanation whatever! In fact you can’t even bring yourself you use the term. In your lengthy answer you haven’t referred to it once!
Its not my theory. It Hubert Lamb’s. The “completely different breed” of scientist to Mann. And regardless of what he thought of AGW just before his death in 1995 when , incidentally global temperatures were much lower, and his views were still widely shared in the general scientific community, he does seem to agree with Mann that the MWP was regional to the North Atlantic area and not a global phenomenon.
There’s no getting away from that fact.
Peter
I’m not the slightest bit interested in Lambs TCV theory. Many years ago he briefly postulated a theory which seems to have been invalidated by later data which he never lived to see. Had he seen later data he would no doubt have postulated a different theory-my money would include jet streams. Climate scientists liked theories and Lamb was no exception.
Max explained all this in #1346. He has cited MWP studies, as have I in my #1348. Have you ever read any of them? The world appears to have been somewhat warmer during the MWP. How much that ‘somewhat’ was is somewhat speculative but Lambs data- drawn from a multiplicty of sources- can be clearly reviewed. To that can be added additional research and our own observations (such as the abandoned medieval vilages 15 miles from my home which were left as the farmers moved down the contour lines as the climate deteriorated. They also changed their crops and the tree line moved with them
‘Global’ temperatures MUCH lower in 1995?-By what criteria?
http://www.cru.uea.ac.uk/cru/data/temperature/nhshgl.gif
Anyway, I am glad you are referring to global temperatures. I think they are worthless and have explained why many times.
You implicitly believe in the validity of a precise global temperature (and to be fair so does Max) so answering my query on why you (or Max) believe SST’s to be scientifcally accurate should be right up your street.
tonyb