The NAS NRC panel on temperature reconstructions has released its report.
The press release states
There is sufficient evidence from tree rings, boreholes, retreating glaciers, and other "proxies" of past surface temperatures to say with a high level of confidence that the last few decades of the 20th century were warmer than any comparable period in the last 400 years, according to a new report from the National Research Council. Less confidence can be placed in proxy-based reconstructions of surface temperatures for A.D. 900 to 1600, said the committee that wrote the report, although the available proxy evidence does indicate that many locations were warmer during the past 25 years than during any other 25-year period since 900. Very little confidence can be placed in statements about average global surface temperatures prior to A.D. 900 because the proxy data for that time frame are sparse, the committee added. ...
The Research Council committee found the Mann team's conclusion that warming in the last few decades of the 20th century was unprecedented over the last thousand years to be plausible, but it had less confidence that the warming was unprecedented prior to 1600; fewer proxies -- in fewer locations -- provide temperatures for periods before then. Because of larger uncertainties in temperature reconstructions for decades and individual years, and because not all proxies record temperatures for such short timescales, even less confidence can be placed in the Mann team's conclusions about the 1990s, and 1998 in particular.
The committee noted that scientists' reconstructions of Northern Hemisphere surface temperatures for the past thousand years are generally consistent. The reconstructions show relatively warm conditions centered around the year 1000, and a relatively cold period, or "Little Ice Age," from roughly 1500 to 1850. The exact timing of warm episodes in the medieval period may have varied by region, and the magnitude and geographical extent of the warmth is uncertain, the committee said. None of the reconstructions indicates that temperatures were warmer during medieval times than during the past few decades, the committee added.
Realclimate on the report:
However, it is the big picture conclusions that have the most relevance for the lay public and policymakers, and it is re-assuring (and unsurprising) to see that the panel has found reason to support the key mainstream findings of past research, including points that we have highlighted previously:
At Climateaudit on the other hand:
I'd characterize it more as schizophrenic. It's got two completely distinct personalities. On the one hand, they pretty much concede that every criticism of MBH is correct. They disown MBH claims to statistical skill for individual decades and especially individual years.
However, they nevertheless conclude that it is "plausible" - whatever that means - that the "Northern Hemisphere was warmer during the last few decades of the 20th century than during any comparable period over the preceding millennium". Here, the devil is in the details, as the other studies relied on for this conclusion themselves suffer from the methodological and data problems conceded by the panel. The panel recommendations on methodology are very important; when applied to MBH and the other studies (as they will be in short order), it is my view that they will have major impact and little will be lefting standing from the cited multiproxy studies.
Update
This should finally put an official end to the silliness that's gone on for the last few years. I don't doubt that McIntyre will continue to bloviate, but journalists especially now have no reason to give him any traction.
My reading of the summary of the report and parts of the text is that the NAS has rendered a near-complete vindication for the work of Mann et al.
Well, the report is out and it seems to be a fairly strong vindication of Mann et al. There is some more fuzzy language that will surely be seized apon by some but there is certainly nothing to support the allegations of errors, omissions and frauds that had been thrown around. The main conclusion is that many other studies support these same findings and that this is not a central issue in the present and future of climate change.
Downloads, etc. are available here.
McIntyre barks, but the caravan has moved on.
So it seems the good and very large ship MBH sails on, loaded with accretions, having (unfortunately) sliced in two a dingy manned by two pirate wannabees. I personally am still waiting to see respectful attention paid to the Bristlecone Pine. It has still not be given the honours it deserves for storing 9000 years (or even more) of climate records.
"I'd characterize it more as schizophrenic. It's got two completely distinct personalities."
Actually schizophrenia refers to disfunction with the perception of reality which if... oh never mind.
Its been a rotten week for the s(c)eptics on several fronts:
http://news.yahoo.com/s/ap/20060623/ap_on_sc/global_warming
However, don't expect the denialists to shut up any time soon. Since a scientific 'victory' has, is, and always will be beyond them (and they know this), they will undoubtedly continue to do everything in their power to continue to muddy the waters in order to ensure that there is no political will to deal with the problem of AGW.
yup, nitpicking is fun!
merriam webster on plausible:
Main Entry: plau·si·ble
Pronunciation: 'plo-z&-b&l
Function: adjective
Etymology: Latin plausibilis worthy of applause, from plausus, past participle of plaudere
1 : superficially fair, reasonable, or valuable but often specious (a plausible pretext)
2 : superficially pleasing or persuasive (a swindler..., then a quack, then a smooth, plausible gentleman -- R. W. Emerson)
3 : appearing worthy of belief (the argument was both powerful and plausible)
- plau·si·ble·ness noun
- plau·si·bly /-blE/ adverb
Hans: I prefer your bingo, and (1) and (2) are the joint winners, while (3) is also ran, being based on the circular arguments, first that tree ring proxy series "generally exhibit strong correlations [the NAS elsewhere rules out ALL statistical correlations as being invalid]with local environmental conditions", when the latter are defined by the former", and secondly, that while there is no real evidence for temperature before 1600, and there is proxy evidence a the Little Ice Age, Bingo, we are now warmer than we were in 1600-1850. Moreover, since there is by definition inhomegeniety between proxies 1600-1850 and measured temperatures 1850-2006, nothing of value can be derived from comparison thereof, more so when there is zero correlation between teh rpoxies and the temperatures isnce 1850. Oh dear, I forgot that correlations are ruled out by the NAS as ever having any validity, unlike the zero R2s which always "prove" their case.
Hans,
Nobody nitpicks more than the anti-environmental crowd. I have been dealing with this lot for almost ten years, and it never fails to amaze me to what depths they'll go to twist the empiricial data to bolster their views. Convenient facts always get in the way, but I have encountered some of the most amazingly absurd arguments one could imagine in defending the status quo.
To be honest, many of the arguments put forward by the astroturf lobbying groups and their coterie of bought-and-paid-for scientists are an embarrassment. I fully understand why Paul Ehrlich said that he was 'depressed' when writing 'Betrayal of Science and Reason'. Paul stated the obvious: why did he have to write a book defending empirical science and a broad consensus amongst his peers against a small group of well-funded shills? Doug Futuyma said more-or-less the same when he wrote 'Science on Trial: The Case for Evolution' in 1982. At that time, with Reagan in the White House, there was a revival in using creation to explain the origins of life on Earth. Futuyma, in the foreward, argued that he felt it was crazy for him to have to write a book defending evolutionary biology at a time when it should have been regarded as factual, rather than just theoretical, biology. And yet, here we are, 23 years later, defending evolution again from the latest political attempt to impose creation on education through 'intelligent design'.
My point is that there is really little difference between these two attempts to undermine science - I see creationism and anti-environmentalism as two sides of the same coin.
"bought and paid for"
Jeff please note that the bulk of skeptics is retired, who finally don't have to consider their careers anymore. I agree there are some strong contrarians, but hey, there are also strong alarmists.
Any idea what the motive of Steve McIntyre is?
Full disclosure.
I have a question regarding the use of tree ring analysis in Mann. Can anyone help me?
I was reading about an essay about Mann's "hockey stick" graph from: http://www.john-daly.com/hockey/hockey.htm
I have summarised his points into these five points, can anyone give me some guidances if they are correct or not, and can someone give me a source so I can read more about it, thankyou.
1. Tree rings are only laid during the growing season, not the whole year, and so they dont tell us little or nothing about annual climate.
2. Tree rings do not record night temperatures since photosynthesis only occurs in the daytime, which mean it get a false impression of the annual mean temperature.
3. All a tree ring can tell us is whether the combined micro-environmental conditions during the growing season were favourable to tree growth or not. This is because tree rings are influenced by numerous factors other than temperature, such as rainfall, sunlight, cloudiness, pests, competition, forest fires, soil nutrients, frosts and snow duration.
4. Trees only grow on land. And since 71% of the planet is covered by oceans, seas and lakes, tree rings can tell us nothing about the maritime climate, even though the oceans are known to be the prime determinants of climate conditions throughout the world.
5. These factors could mean these `annual average temperatures' are seriously contaminated by heat island and other local errors. If the calibrating temperatures are wrong, the whole tree ring temperature reconstruction for the distant past is also compromised.
I've read the chapters describing dendrology, statistical analysis and multiproxy studies, and I think in detail the report is indeed a mixed bag and surprisingly superficial in many cases. The discussion about multiproxy results is severely marred by getting v. Storch and Zorita wrong, and probably unduly pessimistic wrt the precision and accuracy of the studies. (BTW I don't recall our friends Sally and Co. being mentioned). As far as statistical methods, they basically come down right, MBH's original methods had serious problems from the standpoint of statistical analysis, but these did not significantly affect the results. Note how most of the detailed criticism in the NAS report on this point wrt the actual reconstructions goes away when you throw out v. Storch and Zorita. Probably the best step forward would be to have a group of statistically wise men with a couple of climate people sit down and settle on best practices.
Hans,
Any idea what the motive of Steve McIntyre is?
You tell me: people ask me this about Bjorn Lomborg all the time. Pretty well all of the sceptics have their own personal agenda, as far as I can see. In most cases I think its probably political, as many of the sceptics are associated with fervently right wing think tanks that receive large dollops of corporate money and which aim to eliminate or reduce impediments in the pursuit of private profit. McIntyre's name has appeared in the George C. Marshall Institute, which is pretty dumb of him if he wants to assume the mantle of being seen as 'independent'. In fact, most of the prominent sceptics, irrespective of the fact that they are not prominent scientists (the two are VERY different) are probably grinding some sort of political axe. Lomborg, in my opinion, is different: I believe his aim was fervent self-promotion. Heck, being a sceptic often seems to work, frequently elevating completely obscure scientists/academics to celebrity status overnight.
With no disrepsct to McIntyre or most of the other climate change sceptics, how many are esteemed academics with tens if not hundreds of peer-reviewed papers to their name and many more citations? I am a virtual unknown in the public eye (and what is known about me is based on my Nature review of Lomborg's polemic). I've thus far published more than 55 peer-reviewed papers (I have 12 in submission right now) and my articles have been cited more than 600 times in the scientific literature; compare that with Lomborg, with but a single peer-reviewed paper to his name and 21 citations in total. Yet Lomborg is an international celebrity and I am a nobody. I really couldn't care less about this, but it does go to show you that style over substance pays, even in science. How many peer-reviewed papers in the scientific literature does Steven McIntyre have? Or Ross McKitrick? Or Myron Ebell for heavens sake? But each of these guys is sought out as an 'expert' on climate change. I find it hard to take all of this seriously, but the media does.
Jeff, Isaac Held had a good point of this "motivation" for the skeptics on realclimate.org. Basically it's easier for people to take a "skeptical" or "contrarian" stance and just batter away & nitpick at the science. It requires no original thought, and people with no experience in the field feel they can barge right in and make grandiose pronouncements about AGW etc. Plus they are assured of getting publicity from their friends in the right-wing think tanks (CEI, Cato, etc), corporate media etc.
How many times have I seen Myron Ebell (at beest, an economist) on a panel as if he is a "skeptic scientific authority"; and his background is in politics & economics and shilling for right-wing think tanks. And it's a way for these forgotten, retired academics to try and remain relevant, and those stuck in another field at little known schools (i.e McKitrick at U. Guelph) to get some much needed attention.
McIntyre's motivation also seems to be primarily egotistical ("I coulda been an (academic) contender but I became a sellout for mine operators"), as well as sticking with his mining & petroleum buddies by reverse engineering (he claims "auditing") data which he has little or no experience in.
I have a question regarding the use of tree ring analysis in Mann. Can anyone help me?
Yes, I can help:
Stop reading John Daly for understanding.
HTH,
D
But each of these guys is sought out as an 'expert' on climate change. I find it hard to take all of this seriously, but the media does...Yet Lomborg is an international celebrity and I am a nobody. I really couldn't care less about this, but it does go to show you that style over substance pays, even in science.
Yeah, Jeff, but you're a millionaire from being in the left-wing green lobby. Not sure why you're complaining, as you've got all that money and power too. Sheesh. These environazis always want moremoremore, and pretty soon they'll be running the gummints of every country and we'll be eating granola and riding bikes everywhere, while our economies collapse.
[/sarcasm]
Best,
D
Mr Wilson
Using the John Daly site for information on climate change and specifically tree rings as proxy indicators of climate is similar to watching an Adam Sandler film for intellectual stimulation. There is a rich literature on tree rings and climate, I would start with Fritts 1976 text (Tree Rings and Climate). For journals consider the Tree Ring Bulletin (now Tree Ring Research)and Dendrochronologia. With respect to the points that you have raised there are many variables that influence the width and density of the annual growth ring in a tree, some are related to climatic conditions prior to and during the period of growth, while others are related to host of other biotic and abiotic factors. John Daly did not discover this, it has been appreciated for over a century. Not all trees or groups of trees will yield data from which climatic information can be extracted. The science of dendroclimatology is all about extracting that information, where and when possible. Tree rings sites are selected because they represent locations where there is a high sensitivity in the ring growth to climatic conditions. These sites are not urban, often they are near the range limits of the species (e.g. near alpine or latitudinal treeline) Most of the points raised by Daly show a deliberate attempt to misunderstand or misrepresent the basics of dendroclimatology and it comes off as quite silly. For example Point 1: tree rings tell us nothing about annual climate. Spring and summer ring growth can be influenced by climate (weather) conditions in other times of the year, such as winter snowpack depth (e.g. which can influence soil temperatures and moisture in the spring period) and winter temperatures and winds (e.g. which can influence dessication of the plant tissues). In fact the growth in a given years tree ring is not simply a function of the temperature on a group of days or month but rather a function of several months or years preceeding climate. There are series of techniques used in dendroclimatology used to measure the correlations between ring growth and climate that address these issues and result in a proper calibration between ring growth and climate. Tree rings are but one proxy indicator of climate there are many others. They do not exist in isolation which is why multi-proxy examinations are powerful and worthwhile.
"Convenient facts always get in the way, but I have encountered some of the most amazingly absurd arguments one could imagine in defending the status quo."
I am consistently saddened by the apparent inability of the more sensible "skeptics" like Tim C and Hans to condemn the blatherings of the likes of Ken Ring.
For that matter I'd be interested in hearing Hans' view of our recent discussion with TimC about what may or may not have been "displaced" from the atmosphere by the increase in CO2 levels.
To continue the hockey analogy I think that the referees (NAS panel members) as well as making their ruling should also have issued penalties. May I suggest that a two year penalty for high sticking, two years for delay of game, five year penalty for deliberate attempts to injure (the reputation of their opponents) and a game misconduct for unsportsmanlike conduct would be appropriate? I think we all know whose numbers are on the jerseys of those who should be sent to the sin bin.
it is kind of noticeable that the good TimL merely quotes other people, and doesn't deign to put his own thoughts down about the NAS report.
What's the matter, Tim ? Frightened ?
MBH claimed 95% confidence limits for the last millenium, and claimed that the 1990s were the warmest decade of the millenium at P<0.05. The NAS panel have rubbished that claim.
MBH's claims are now "plausible".
I do believe that Tim is being circumspect, and I can guess why :-)
cheers
per
per, if you want to comment here, please use the name "David Bell".
Your assertion that MBH gave p value of <0.05 for their claim is a fabrication.
Of course, there is another "hockey stick" involved in climate change; when Carolina beats Edmonton for the Stanley Cup, you know something must be seriously wrong with northern winters.
"Taking into account the uncertainties in our NH reconstruction (see Methods), it appears that the years 1990, 1995 and now 1997 (this value recently calculated and not shown) each show anomalies that are greater than any other year back to 1400 at 3 standard errors, or roughly a 99.7% level of certainty."
what was that about fabrications, tim ?
I do also notice that you are very keen to hide behind other people's comments on this, Tim ? you appear to be frit ! scared that steve m. will come in and take you apart again ?
toodle-pip !
per
p.s., don't forget:
http://timlambert.org/2005/02/brignell2/
Yes Jeff I believe you have published 55 pieces in the peer reviewed literature. But after 30 years of science journalism I am just not impressed anymore. Have just seen too many examples of failure of this system, crap getting through, good stuff being blocked. Lots of peers, little review, and instead of acknowledging the faults of the system and trying to remediate it you simply keep on repeating the old mantras. Somewhat autistic really
The hockeystick and stem cells controversies both show: peer review is not enough, certainly not when a particular science receives a lot of public attention. Then an audit is absolutely necessary. There just is too much at steak. The more you shout at the competition the less I trust you. You could regain trust if you, or the people you suggest to represent, approached people like M&M and engaged in an open debate. But your behaviour in the Lomborg debate has shown that you want anything but that. You wonder about the psychology of McIntyre and others, but you do not clarify your own motivation. You are angry, but you do not want a solution. Why would anyone take you serious then?
Dear Jeff Harvey,
if you are interested in my secret personal agenda why I am so deeply irritated by the alarmists and spend time on it, it is because people with sloppy reasoning and a dishonest approach who never wanted to understand things in quantitative depth and who preferred to build on their large number - the large number of sloppy and dishonest people - have always been poisoning my life.
I only had a vague idea that the field of climate science was not exactly an example of a sharp, rational, unbiased treatment of questions - simply because the worst physics students in Prague chose that field - until I studied how it actually works which was a shock for me (several years ago, after the 2000 elections in which my ideas and opinions about these matters were largely neutral). I simply dislike crackpots, people like you (if you allow me to be explicit) who want to politicize all questions and whose dishonesty can be seen on 50% of their acts.
I mention you in particular because I have also studied your shameful exchanges with Prof. Lomborg which made me ashamed to be a remote part of the same community as you are.
The hysteric global warming movement is an irrational politically motivated and dogmatic framework to study uninteresting questions in an unscientific way whose goals are pre-determined (although rationally unrelated to the questionable scientific findings), combined with a the desire to increase the amount of bias in between science and journalism as much as possible, in order to fool all people into believing that we face a major threat which would allow far left-wing people to try to establish new methods how to control every individual citizen and corporation on this planet.
In reality, there is no material evidence that the recent warming is unprecedented on the millenial timescale; there is very little evidence that we can already disentangle the human influence from the natural background; and there is an overwhelming evidence that the proposed policies are just a waste of money; and there is a significant evidence that many people with power over climate science - such as you - are using strikingly unfair tools to deal with the people whose conclusions are politically inconvenient.
I am happy to see that it is plausible that the NAS members are not quite like you.
Best wishes
Lubos
It truly is astonishing that someone of the character of the previous poster holds a position at an American University. Many words but no substance, much like string theory. Evidence would suggest that the worst physics students in Prague did in fact not enter the physical sciences but rather have slipped into an alternate reality dominated by paranoia.
So Lubos, a string physicist, holds up Lomborg, an economist (not to mention economist McKitrick & "mineral engineer" McIntyre) as climate experts.
Is there any other field in which so many hacks from outside of the field claim to be the experts?
per/David Bell seems to think that a millenium is 600 years ...
"Your assertion that MBH gave p value of <0.05 for their claim is a fabrication."
"a 99.7% level of certainty."
I still think you are scared to say anything substantive on this, 'cos when you do, you are shown up.
cheers
per
Anyone have access to the latest Lancet? Check this gem. "Analyses of the 2003 heat wave in Europe have concluded that it was a truly extreme event and the summer of 2003 was probably the hottest in Europe since 1500", from the paper (actaully a public lecture transcript) Climate change and health, The Lancet, Volume 367, Issue 9528, 24 June 2006-30 June 2006, Page 2101-2109. Fiona Sima and Phil Mackiea.
Worthwhile considering for the 'global warming is good for you' crowd. Dammit, how can these climatologists keep getting it wrong when they have economists trying to set them straight? Don't they have economists in the various NAS?
Jeff,
A scientific topic that has become so important for political decisions needs only one thing: Full disclosure.
Show the data, show the method, show the result.
Mudslinging doesn't help.
Ian Gould,
Once more: Ken ring is a crackpot.
The current rise in atmospheric CO2 is manmade. From the anthropogenic emissions approximately 40% per year is sequestered in sinks. The sinks are not saturating but increasing.
http://home.casema.nl/errenwijlens/co2/sink.htm
Great! The pseudo-contrarians are coming in thick and fast!
First, to dipsense with Lubos: If you want to debate me an any of the gobbledegook in Lomborgs book e.g. cherry picking data, ignoring piles of relevant studies with different conclusions, consistently mistaking correlation with causation, basically dispensing with the natural economy and focusing on the material economy (in spite of the dependence of the latter on the former), misquoting scientists or making unsubstantiated smears to undermine their status, misunderstanding important but basic concepts in environmental science, etc. etc. etc. etc. then feel free to do so. I debated Lomborg in Holland in 2002 and I raised all of these salient little points with him, and, give fifteen minutes to rebut me, he did not even try, except to defend his feeble attempt to smear the reputations of Edward O Wilson and Paul Ehrlich. Why? Because he couldn't, Period. I didn't find the guy at all intimidating because he knows so little about a field I have studied for ther past 20 years. Is it any wonder that several attempts were made for us to debate before and after (or to speak at the same venue) and Lomborg either claimed to be 'busy' or actually backed out? Some advice Lubos: don't waste my bloody time with pedantics. Sound science is not based on your whatever-motivates-you-today and you know it. I have no idea what does motivate you in elucidating the truth in science, as elusive as that is, but to reiterate, science is against you and the majority of 'denialists' with respect to the fact and potential consequences of anthropogenic global change (including global warming). Most importantly, Lubos, for every one of you who is 'ashamed' of behavior re: Lomborg and his book, I have received reams and reams of support from fellow scientists, incuding some who are leaders in their fields of research. I was quite delighted that Edward O. Wilson gave me particular thanks, something he rarely does. Thus, your opinion means nix to me.
Theo, I assume that you are one of the coterie of Dutch contrarians that make my life a misery. And sure I am angry. I am angry when I see science being distorted, mutilated, twisted, and throttled to bolster a political/corporate agenda and a single worldview. I am angry when I see people who have done little, if anything, to advance our knowledge in critically important areas of fundamental and applied science suddently throw their hats into the ring to espouse that they are the new 'sages of wisdom' who have 'seen the light' and who argue for policies to maintain the staus quo in spite of the vast abyss in which humanity is headed. I am angry because these people have, to partially quote John Holdren, crossed the line that divides controversial, if not rigorously performed science, from complete rank incompetence. They have wasted a lot of people's time with their histrionics, and have seriously muddied the public's understanding of important contemporary issues. At a time when we need to confront the political, social and environmental impediments in order to secure a sustainable future, there are powerful, vested interests who are doing everything in their power to ensure that what remains of the planet's material and economic wealth remains in the hands of the privileged few - irrespective of the costs in the mid to longer term. These forces are intent at maximizing short-term profit for a few at the expense of long term security for many. I have lectured widely on this topic and none of this should be at all controversial - it is only because of the power that the elites have used in manipulating information through the mainstream media and their utter contempt for public opinion is it that my words are interpreted by some to be 'outlandish' or even 'crazy'.
The fact is, like it or not, peer-review keeps science safe. Without it, every crackpot idea - from flat earthers to alchemsts to creationists - suddenly becomes a part of the mainstream. The MBH paper was rigorously peer-reviewed; your dislike of peer review is probably because the conclusion of the MBH paper does not blend with your own view on climate change. Tough. I see an analogy with the recent pronouncements of support for 'democracy' by Bush and his neoconservatve government (after all of the other conditions for attackign Iraq were proven to be based on fabrications). Where democracy supports the political, military and above all economic interests of US corporations and financial institutions, it is supported. Where it conflicts with these interests, it is downplayed or even ignored. These are not my words, but quoted in part from Thomas Walker, who held the portfolio overseeing "Democracy Enhancement" in the Reagan administration. The analogy also applies to those who support the broad scientific consensus on AGW and those who don't. This, Theo, may explain your contempt for peer-review.
One last point: reading Lubos' post, one would get the idea that M & M were vindicated by the NAS panel. Earth calling Lubos... wake up man! What gives you the power to understand AGW in a way that the 2,500 scientists contributing to the 2001 IPCC draft doesn't? Or the NAS panel for that matter? Their conclusions remain unchanged: that the last 20 years of the 20th century were very likely the warmest over the planet's surface over the past two millenia, and that human forcing is likely to play a significant role. No scientific panel will ever go further than this! The results literally vanquish the arguments of the denial lobby. Utterly demolish them! Yet, you come on then come on here to defend the NAS by implying that they downplay the human component? AAAAAAAAAAAAAARRRRRRRRRRRGGGGGGGGGG!!!!!!!!!!
"Their conclusions remain unchanged"
wrong. The NAS panel specifically disagree with the claims of MBH'98; specifically, they stated that reconstructions from before 1600 have unquantifiable levels of uncertainty. This is very different from MBH'98, which claimed 99.7% certainty.
"that the last 20 years of the 20th century were very likely..."
the NAS panel did not use "very likely"; they used "plausible"
"The results literally vanquish the arguments of the denial lobby."
wow. i am feeling vanquished already. If only you hadn't got your words completely wrong, and if only the words didn't mean something completely different, you would be right.
cheers
per
Dear Jeff Harvey,
besides reading my postings, it may also be a good idea for you to read the report. The NAS report has confirmed every major technical criticism of MBH by M&M and has not found any problems with M&M. It confirmed that the usage of the PCA method was wrong; the statistical significance of all results before 1600 is zero (which, by the way, means that the whole MBH99 is bogus); it said that the bristlecone pines should not be trusted as temperature proxies (these trees were primary to obtain the "hockey stick" shape); they criticized that the data and software were not available; the panel has announced that all dendro conclusions before 1100 are statistically worthless, and so forth, and so forth.
You ask: "What gives you the power to understand AGW in a way that the 2,500 scientists contributing to the 2001 IPCC draft doesn't?"
Sorry to say, but the answer is my much higher ability not to fool myself and my higher intelligence and physics background than 2480 of these 2500 people. If you read the amount of politics and amount of completely untrue ad hominem accusations that you and your colleagues have written above, you might in principle become able to understand why my ability to judge these questions exceeds not only the average of 2500 people in the climate science. This is about a rational vs. irrational approach to questions. Once again, climate science is not exactly string theory, so you can't expect that it will remain unaccessible to economists, high-energy physicists, and former mineral consultants (who was the #1 mathematician in Canada, by the way).
All the best
Lubos
Lubos has determined his intellect is superior to 2480 of the 2500 scientists who worked on the TAR. This can't be right surely Lubos must be second to no one. Now Lubos what was your methodology, do we have access to the data? We demand full disclosure. There should be an audit, perhaps the "#1 mathematician in Canada" could assist.
So Lubos offers "arguments from authority." Gee, Steve Mac was the "#1 mathematician in Canada", BWAHAHAHAHAHA. Is he also the #1 squash player and #1 guitarist? What a joke.
Lubos,
I have read about 2/3 of the report now, and am continuing reading it.
Yes, they point out that the resolution prior to 900 years ago from the dendro recrods means that the error is too large for teh analysis to be meaningful, and that the reconstruction before that may not be real at all.
However, they also review a lot of other data - glacier dynamics, glacial artifacts, ice cores, sediment cores key among them - and arrive at the conclusion that AGW is still pretty damn strongly supported.
Honesty on your part would require you to acknowledge that - instead of engaging an ad hominem attack of your own, aimed at my typos.
But then, you are clearly so superior to everyone else that you don't have to bother to live by your own rules.
"all the best"
-Lee
Darling Lubos has been told that he is the smartest kid in the class so often that he believes it. He tries to use this to blow others off. In any venue except this, he would get a bloody nose for acting the way he does. Actually, I suspect that he did for most of his childhood and now having escaped that fate thinks that he can let it rip.
Unfortunately for Lubos, you have to crack the books occasionally. Jeff Harvey knows a lot more about the systems he deals with than Lubos, and no amount Lumo like posturing can hide it. The thing many are looking forward to is what happens to sweet Lubos when he loses the position. An Assistant Professor at Harvard who did not get tenure ain't nearly as imposing as an Assistant Professor at Harvard.
Our little bubbly boo Lubos might do well to contemplate the future and start making nice. As it is there are a lot of people who would not spit in his ear if his brains were on fire.
Lubos was called to testify in a lawsuit, which contested the claims of String Theory against Quantum Loop Gravity. The lawyer was skeptical. "What makes you such an authority?" he asked. "Oh, I am without question the world's most outstanding theoretical physicist", was the startling reply. It was enough to convince the lawyer to change the subject. However, when the witness came off the stand, he was surrounded by protesting colleagues.
"How could you make such an outrageous claim?" they asked. Lubos defended, "Fellows, you just don't understand; I was under oath."
(Stolen from [Leon Lederman](http://www.edge.org/q2005/q05_5.html).)
"former mineral consultants (who was the #1 mathematician in Canada, by the way)."
Based on...? Is there a CI95 or similar that goes with that?
Eli, I just found this from Maria Spiropulu, while browsing the site at your Leon Lederman link. It seems relevant. Emphasis added.
"Following Bohr's complementarity I would spot that belief and proof are in some way complementary: if you believe you don't need proof, and (arguably) if you have proof you don't need to believe.(I would assign **the hard-core string theorists who do not really care about experimental scientific evidence** in the first category).
Very nice. Note that neither of you has mentioned - or responded to - a single particular question about the climate. No one wants to discuss the correlation coefficients; influences on the bristlecone pine growth; the circulation of water and the growth of ice.
It's because you don't know anything about it, you're not capable to think about these things, and you are not even interested in them. In fact, you are scared by science, much like many other people whom you believe to reach my toes. Your writings are the best evidence what you're really interested in: to say just the opposite of the truth, convince other challenged people about these untrue things, and use the general ignorance for political purposes.
Unlike you, I don't need to talk about my intellect, unless I am asked, because most people know quite a lot about it, and it is definitely not about being the smartest in the "class".
Compare the lousy quality of your hysterical activist blogs with the decent, dynamic, and scientific debates at climateaudit.org.
Ok Lubos
What about the influences on pine, water and ice? What is your point? It difficult to comment on the underlying science because you have made no remarks on the science, only vague and untested claims that you are a superior being.
http://scienceblogs.com/deltoid/2006/06/nas_report_on_hockey_stick_rel…
err Lubos, compare the hilarious brushing off of detection & attribution studies & climate modelling that continually goes on at climateaudit. It's obvious that anything outside of Steve's (and his cheerleaders) area of statistical games with multiproxy studies just has to be bashed so they can't be concerned with it. When confronted with a real mastermind in the field, like Hans van Storch, the cockroaches go crawling under the woodwork and making lame excuses that they simply "don't believe" D&A studies etc. Which is why I've always said, in my flames over there, it's only good for entertainment. I've never seen a bigger bunch of self-absorded pseudo-intellectual twits.
"However, they also review a lot of other data - glacier dynamics, glacial artifacts, ice cores, sediment cores key among them - and arrive at the conclusion that AGW is still pretty damn strongly supported. "
the remit of the nas group was reconstructions over the last two millenia; and they made some fairly clear statements after reviewing the data and theory. Their comments are fairly damning for MBH'98 and '99.
Although there is a chapter on models, I find it difficult to imagine that the NAS panel attempted a comprehensive review of the evidence for AGW. Indeed, the chapter seems to focus on how reconstructions are used with the models.
The review was on reconstructions; i find it perplexing that you should suggest that "AGW is strongly supported" can be a vindication of the fact that the committee does not support the principal conclusions of MBH'98/ '99.
cheers
per
"Which is why I've always said, in my flames over there, it's only good for entertainment. I've never seen a bigger bunch of self-absorded pseudo-intellectual twits."
Dear Carl
the quality and impeccable logic of your argument does suggest that you are better placed on Mr (frit) Lambert's blog.
toodle-pip !
per
per, are you simply unable to understand what I say, or are you being dishonest. Adn have you bothered to read the report?
Theri statements are that the methods of MBH are flawed,a dn the undertatinties prior to 900ya mean that one cant interpret the reconstructions from them. I've said that quite explicitly, so what the f**k are you on about?
They also point out quite clearly that this does not alter in any substantial way the conclusions from a lot of interrelated and inter-verifying lines of evidence, that AGW is happening. They also say that this other evidence means that Mann's claims that the 20th century and the later decades are anomalous, are, they say "plausible," and in other places, they show explicit evidence showing clearly anomalous 20th century climate.
I know that a large part of the climateaudit wolf pack is bent on destroying Mann, and somehow feel that this would disprove AGW. Sorry to disappoint you, but yelling repeatedly "Mann got the statistics wrong" does not change what the committee actually said about AGW.
per, I stand by my statement that CA & it's pseudo-intellectual lackeys are only good for entertainment. The paid-off Canuck team of M&M have done what, provided one peer-reviewed paper over the last 5 years, with some statistical games on MBH98. It's hardly the "smoking gun" you cheerleaders wanted. "Toodle-pip" yourself.
Unlike the rest of you, Lee is at least trying to prove global warming by scientific arguments. Below, I attach his most convincing work proving the global warming - unedited. As you can see, what I wanted to say is that climateaudit.org has a very high average quality of the contributions; it was not a universal A grade. ;-)
http://climateaudit.org/?p=715
Lee wrote:
#481. Lubos, yo are jsut too silly.
Disputing straw-mn forms of cliams I HACE NOT MADE isn't even first year physics, its first week debate, and the tactic of someone who isnt secure in his argument.
Adn on the one place where you are at least near the point, there is some worming ,soem off which is likely AGW, and theris MORe heat increase, which wil translate to warming as heat flow continues due to teh increaseed CO2.
BTW, you are implyign that there is some kind of curoff beyond which CO2 has no relevant effect. Either you really do know some physics adn knwo somethig aobu tthis field, in which case you know that the logarthmic result of CO2 concentration for heat retention is calculated and supported by physical results, and not all that steeply declining as you imply - in which case you are being dishonest - or you dotn know, in which case your physics really sucks..
another funny hypocrisy for the Lubos crowd, i.e. string theorists who bash climate scientists. I mean, come on,
string theory has absolutely no scientific reproducability, yet you're so keen to be on the McIntyre "audit" bandwagon. And Steve Mac's fave claim-to-pseudo-intellectual fame "Wall Street Journal" even bashes sting theory, HAHA!
http://www.nwfdailynews.com/articleArchive/jun2006/notevenwrong.php
physicist, heal (or at least audit) thyself! ;-)
Lubos, I am a shitty typist; mea culpa.
But I at least address what you say, whereas you attribute to me arguments I havent made, in straw-man idiotic form, and then pretend that you have somehow one-upped me when you dispute them.
It is a fundamentally dishonest technique, and it is one of your most frequelty used.
Adn at least I'm not tryign, as you are, to defend the assumption that temperature increase to the new steady state temperature should be effectively instantaneous with increased heat. I'm just a lowly biologist, but even I know better than that.
Dear Carl,
look at yourself what kind of a thinker you are. You see that someone has found scientific conclusions in a field that you don't understand - namely the climate science - so your reaction is to jump into another field that you understand even less, by several orders of magnitude, namely high-energy physics.
Do you think that a relatively smart kid from the basic school would believe you that you have defended any statement about the climate by jumping to completely absurd and crazy statements about theoretical physics? You have absolutely chance to compare with me in the climate science that is supposed to be your field. Do you think that anyone will believe you that you can say something useful for us about theoretical physics that you have not seen in your whole life and we have studied it intensely for decades, with all of our 160 of IQ?
People like you are intellectually and morally deficient parasites of the society and I wonder how many more years we will need before someone takes notice. Among the far left-wing fanatics like all of you here, the truth has no value whatsoever. All your lives are based on a gigantic pile of lies, and whenever one of you is inconvenient for others, they pick one of these lies and start to intimidate their former colleague even though this lie has nothing to do with their previous lie.
Sorry, but we in science are actually doing science which is an organized and rational search for the truth. If it is done properly, we can clearly see, for example, that string theory is the only mathematically possible framework for physics beyond quantum field theory, and we also see that it is impossible to extract any temperature signals before 1600 that would allow us to say anything about the comparison of the present climate and the medieval climate.
You don't like it, for purely political reasons, you will never like it, but you are irrelevant for science. You should enjoy the salaries that you and similar parasites are still receiving from the public sector, and at least close your mouth.
Best wishes
Lubos
"absolute chance" -> "absolutely no chance"
oh my...
*edging away from the ranting gesticulating guy on the street corner...*
Dear Lee, when you're a biologist, it is certainly more justifiable that you have elementary holes in thermodynamics, including the meaning of the word "heat". But why the heck are you trying to argue about these physics questions with a physicist? And modestly speaking, with a physics assistant professor from Harvard? Do you really feel so sure that you understand these things better? Or is it just because you were educated in an environment in which regardless how much idiotic statement you made, it will be applauded as long as it is a fanatically left-wing statement? I just can't understand these things. 99% of the things you wrote is complete crap. You must suffer from a complete inability to judge your own abilities. Best, Lubos
Lubos, You are the one arguing that one should assume that there is no lag in temperature increase with increased net heat transfer to the earth.
Have you ever put a teakettle onto a flame? Clearly, by your argument, that fact that it doesnt boil immediately means that it will never warm up.
err, Lubos, I've worked with more climate scientists than you probably have worked with your dead-end field of "string theory." again, it's laughable that you can't even do anything in your own field, so you're trying to jump over to climate by riding the coattails of some Canadian hacks who also aren't in the field. I guess you're a Czech anachronism, puffed up with your own ego and appeals to your inflated intelligence (you share that with Mc & Mc)
>Sorry, but we in science are actually doing science which >is an organized and rational search for the truth.
HAHAHA, yeah right, and you do that by zealously following non-scientists such as M&M, and slamming the climate scientists in the field. What you and your Cato-Institute-esque minions offer is "faith based science" -- not surprising since you're a relic of the unproven & unworkable "string theory." I sort of know how you must feel, 10 years ago I was doing a PhD in Artificial Intelligence, but I grew up! ;-)
Oh Jeff H.,
There is a band, I think they call themselves the Right Brothers, who made a song 'Bush Was Right'. You can Google for the clips or better, don't: they're funny and fun is an area where you havent been seen for a long time. I think the band made that song for that particular kind of people that start to spout blood from their ears as soon as they hear the name of the President of the US ( with whom I do not agree on the Iraq/stemcell side, but wholly on the Kyoto side btw).
I know very well what the advantages are of peer review, but I do not understand your fetishism about it. It is so abundantly clear that PR is only a small first step to good science, but from your postings I understand that peer review is beginning AND end of good science. I would have thought that the fact that Bjorn Lomborgs book was peer reviewed would have made you thinking, but apparently not.
There are a lot of papers in which sensible people ( I really wouldnt know how to divide them along your favorite pro/con Bush scheme) ponder the merits of the peer review system and try to think of alternatives, changes, but apparently it doesnt reach you. One of these ideas is an audit. What do you think of that? I am not going to check your postings to find out whether you think Steve McIntyre is an oil-stooge, but even if he were, what do you think of his suggestion to archive data and make them more freely available. Wouldn't that advance science? Are your insect-data archived? Publicly available? Btw Lomborg was audited as well and no major errors were found.
And also: your apparent conviction that only a graduated fashion specialist ought to be allowed to say that the emperor has no clothes is beyond comprehension. Aren't you an insect-specialist? To what areas does that qualify you? Do not misunderstand me: I judge people by what they say, not by their position, so you are welcome, but is it not you yourself who makes Jeff Harveys life so miserable?
Theo-
umm..a ctually it is NOT true that Lomborg was audited and no major errors wer found. He was investigated for fraud, and they found, jsut barely, that teh charge of overt fraud in his wrogn statemnts could not be supported. From Wikipedia:
On January 6, 2003 the DCSD reached a decision in the complaints. The ruling was a mixed message, finding that the book was scientifically dishonest, but Lomborg himself not guilty by virtue of lack of expertise in the fields in question.[3] Specifically, they cited TSE for:
1. Fabrication of data;
2. Selective discarding of unwanted results (selective citation);
3. Deliberately misleading use of statistical methods;
4. Distorted interpretation of conclusions;
5. Plagiarism;
6. Deliberate misinterpretation of others' results.
The wording of the ruling left no doubt that the DCSD, while not finding Lomborg guilty, was not exonerating him either:
Objectively speaking, the publication of the work under consideration is deemed to fall within the concept of scientific dishonesty. ... In view of the subjective requirements made in terms of intent or gross negligence, however, Bjørn Lomborg's publication cannot fall within the bounds of this characterization. Conversely, the publication is deemed clearly contrary to the standards of good scientific practice.
so how was Lomborg's book "peer reviewed" and "audited?" It was reviewed by, say, fellow economists of Lomborg who know zilch about climate? Why don't you post some actual facts to your claims before you "pooh pooh" everyone? It's hilarious that the skeptics come from every area BUT climate science!
Lomborg is a statistician. AFAIK he is not an economist and The Skeptical Environmentalist was not peer-reviewed (but then neither was most of the material it discussed).
http://www.lomborg.com/biograph.htm
OK, he's a political scientist (from his bio above), I don't see anything about statistician (I was wrong about him being an economist although his work seems to be of an economist bent, i.e. Copenhagen Consensus). And his "anti-AGW arguments" are mainly from an economic cost-benefit analsyis rather than on climate science.
Lomborg's lil' book is a polemic, put out in the Social Science section of Cambridge books.
And why folks believe that a PoliSci prof can wade into about, oh, twenty disciplines in which maybe he has taken a class and think that he can repudiate the entire discipline in one lil' book is beyond me. Maybe the denialists will grasp at the smallest straw to uphold their rose-colored worldview.
Pathetic little wankers.
Best,
D
Lee:
"I know that a large part of the climateaudit wolf pack is bent on destroying Mann"
straw man #1
"feel that this would disprove AGW."
straw man #2
""Mann got the statistics wrong" does not change what the committee actually said about AGW."
Of course, the committee was about temperature reconstructions, not AGW; and we agree that Mann got the statistics wrong.
CarlC:
"The paid-off Canuck team of M&M have done what, provided one peer-reviewed paper over the last 5 years, with some statistical games on MBH98."
I make it at least three peer-reviewed articles, 2 replies in GRL, and an NAS review of their work which agrees with their criticisms of the "statistical games" which are the essence of MBH'98.
toodle-pip!
per
Fascinating that Lee makes accusations of dishonesty.
he quotes from the wikipedia page on Lomborg, giving the details of the DCSD decision of 06/01/03.
What Lee fails to mention is that on the same page, it says that the Ministry (on 17/12/03) found that the DCSD decision was flawed, and that the DCSD subsequently invalidated its previous findings, and found lomborg not guilty of the charges.
So it is TRUE that Lomborg was audited by the DCSD, and that he was found not guilty on all counts.
I am just wondering why anyone would post such selective, and misleading information ? Is this really the standard of deltoid ?
yours
per
per is counting M&M publishing in the Oil Executive Quarterly as a "peer reviewed journal" HAHA!
"Do you think that anyone will believe you that you can say something useful for us about theoretical physics that you have not seen in your whole life and we have studied it intensely for decades, with all of our 160 of IQ?
People like you are intellectually and morally deficient parasites of the society..."
Yes but at least they're "intellectually and morally deficient parasites of the society..." who can construct a basic sentence in comprehensible English.
per, actually, if you read the part I posted, it says right there that they didn't find Lomborg guilty of the charges in the first place. I said so, too. As I specifically said, he was investigated and exonerated of charges of scientific fraud - and this did NOT constitute passing an audit of hsi work which was the precise claim that had been made and that I was disputing. I didn't cite the remainer of that because it was not relevant to the question of whether Lomborg had passed an audit. You are imagining that I argued a differnet point fromteh one I actually argued - and imagination is no substitute for the truth, per.
But even if I had claimed something closer to what you seem to imagine I claimed, the remainer of that does not help his case. Lomborg's subsequent "appeal" from NOT being found guilty of fraud, reversed a subset of the findings of fact that the original committee had come to in NOT finding Lomborg guilty of fraud.
Here is the remainder of the Wikipedia text on that case:
"On February 13, 2003, Lomborg filed a complaint with the Ministry of Science, Technology and Innovation against the DCSD's decision.
On December 17, 2003, the Ministry found that the DCSD had made a number of procedural errors, including:
* The DCSD did not use a precise standard for deciding "good scientific practice" in the social sciences;
* The DCSD's definition of "objective scientific dishonesty" was not clear about whether "distortion of statistical data" had to be deliberate or not;
* The DCSD had not properly documented that The Skeptical Environmentalist was a scientific publication on which they had the right to intervene in the first place;
* The DCSD did not provide specific statements on actual errors.
The Ministry remitted the case to the DCSD, which invalidated the previous findings of scientific dishonesty in regard to the book. The Minstry also instructed the DCSD to decide whether to reinvestigate.
On March 12, 2004, the Committee formally decided not to act further on the complaints, reasoning that they had already found Lomborg not guilty. This effectively closed the case."
----
So they found that Lomborgs statements in many, many fields which are not social science, cant be fraud because the committee didnt properly outline the standards of scientific practice in the social sciences. Got it - one hell of an andorsemetn of Lomborg's claims there - not.
They didnt properly define whether distortion of scientific facts had to be deliberate or not to be fraud - note that this doenst address whether the committee did or didnot find that it was deliberate, only that they didnt properly define it. Another endorsement of something, but not his acuracy.
TSE may not even be a scientific publication, and they didn't adequtely establish that it was scientific at all, so it cant be scientific fraud - one HELL of an exoneration there of his scientific claims, per. Stunning, in fact. A major win in an "audit" of his "scientific" work.
They didnt provide specific descriptions of errors - so they didn't examine the truth of his claims, only the way he arrived at them - and since he was a social scientist and TSE may not even have ben science, his methods cant be fraudulent.
You cite this and charge that I hid exonerating data? Get real, per.
"...I don't see anything about statistician...."
Carl,
From your link: "It all started in 1998, when Bjørn Lomborg is an associate professor at of statistics in the Department of Political Science at the University of Aarhus."
Theo,
Lomborg's book was audited - by scientists such as myself after it was published. We have found literally hundreds of major errors and omissions - stuff that slipped through the CUP peer review system. If these errors were to be incorporated into a revision, Lomborg would have to drastically alter his conclusions - something which would undermine him completely. One example pertains to his assessment of area-extinction models based on predictions of exponential decay. The models predict that 'x' amount of habitat loss results in 'y' numbers of extinctions. The models have been widely tested, as I garnered some 40 studies published in three rigid journals - Science, Nature, and PNAS since the mid 1990's which provided empircal evidence either supporting them or suggesting that they actually underestimate local extinctions because they exclude other processes which drive the loss of species and populations e.g. invasive species, pollution etc. Yet Lomborg claims to debunk the models on the basis of three examples which he gleaned from an article in a book written by two business economists - Julian Simon and Aaron Wildavsky. What is worse is that each example was corrected in issues of Nature and Science that were published more than 4 years before Lomborg wrote his English edition - yet neither corrective is cited in "The Skeptical Environmentalist". Moreover, when I assertively raised this point with Lomborg in our 'debate' he squirmed about uncomfortably in is chair and then said he'd "Look into it". But of course he won't. The revised edition of his book, when it eventaully comes out, won't change one iota. If he was to include only a few of the 40 studies, he'd have to conclude that the predictions of area-extinction models have been tested and are fundamentally sound.
Lubos, as self-annointed expert on life, the universe, and everything, please tell me why Lomborg did ot include the correctives? As a scientist, I would expect you to condemn this selectivity in citing empirical work, especially as it relies on a book chapter by business economists over two papers in leading scientific journals (plus 38 more). Or do you think that its OK for scientists to selectyively cite literature and to draw conclusions from this? There are many other similar examples like this - Kaare Fog has listed them on his web site 'Lomborg errors'. On acid rain, forest loss, climate change, etc. etc., Lomborg is super-selective in citing only papers that downplay anthropogenic effects, and omits many more that emphasize anthropogenic effects. And you support this? Why? I think the answer lies more in your political worldview than in anything else. Lomborg also attempts to smear scientists like Wilson and Ehrich by suggesting they support a plan that, as described by anti-envirionmental writers Mann and Plummer, that does not exist. I have seen this method used before by the anti-environmental crowd; in order to disarm your opponents and to legitimize yourself all you need to do is make your opponents look like a bunch of idiots. For Lomborg, with no scientific credentials whatsoever,
As for Theo, he's be delighted if peer-review was such that all of the transparently shallow contrarian literature was published. This is why I cited the carrothers quote yesterday - peer review is fine if it supports the arguments of interlopwers like M & M, but it fails because 99.9% of the articles published in peer-reviewed journals go the other way.
Re: the Bush video, Theo, grow up. Read some history. I do.
"a professor of statistics in the Department of Political Science"? That doesn't make sense. Since when is statistics a subfield of Political Science?
Since when is statistics a subfield of Political Science?
Well, somebody has to teach statistics to the politics students. Maybe the mathematicians couldn't be bothered? I could understand that. Anyway the preface to TSE gives a hint as to Lomborg's daily work:
The rest of the book is the "but".
Per, or whoever you are,
The decision to exonerate Lomborg by the Rasmussen government was a political one. As Stuart Pimm said, "It was a pardon from the political leadership". The Danes couldn't exactly retain Lomborg in his post with the Dishonesty decision hanging over him. Hundreds of pages of evidence of Lomborg's dishonesty were submitted to the DCSD. Lomborg did not respond to any of the charges, but instead claimed he'd answered them before, which he hadn't. What we gleaned from all of this is that its apparently OK in the social sciences to be super selective in the references cited to support a position, even if this means ignoring 90% of empirical studies. Well, in the Earth sciences, this is unacceptable. But since Lomborg's book effectively dispenses with the natural economy, arguing that humans are more-or-less exempt from the laws of nature, then he gets away with it.
If you are going to wade into a debate in which you know nothing, then be prepared to take a big fall.
Correction to my last comment: "the fall of 1977" should be 1997.
An audit of Lomborg and an audit of the arguments of his opponents is here: http://www.stichting-han.nl/lomborg.htm
You can also find a lot of useful information on good scientific practice there.
And as far as whether the peer review was allright Cambridge University Press was even supported in this by the competition: http://sciencepolicy.colorado.edu/publications/special/comment_peer_rev…
And Jeff, there still are a lot of questions you havent answered: does the peer review system have flaws and what are your ideas about how to improve those (replace PR with a real PolitBureau perhaps?). Do you archive your data so that others can check your work? Where? Did you ever apologize to Lomborg for that Holocaust-argument? Or have you backed it up with a peer reviewed study?
First Lomborgs victory, now Steve McIntyres victory, you guys are losing.
Theo,
Grow up man. The HAN hardly audited Lomborg's book - the real audit was by Kaare Fog, whom I mentioned earlier, and by dozens of scientists such as myself who have actually bothered to study areas that Lomborg hashes up in his book. When Lomborg stated in the preface that "I am not an expert as regards environmental problems", he made his best and most accurate comment in TSE. I debated a senior HAN member a few years ago on the subject of the importance of biodiversity and was annoyed at what a waste of my time it was: the guy didn't have a clue about the subject. How can they 'audit' a book if their understanding of some relevant tpics is as bad as Lomborg's?
As for the Nature review I wrote with Stuart Pimm, I stand by every word of it. The analogies we used to describe Lomborg's pathetically poor understanding of extinctions are appropriate. Its the unknowns that are the problem: the vast majority of species and genetically distinct populations have never been formally classified, and thus there is no doubt that many have disappeared without being ever being known. This is the same trick used by those to deny there is an AIDS epidemic or fasciost sympathizers have used to deny the Holocaust. Its the same tactic being used by US/UK governments to deny that there has been genocide caused by western bombs in Iraq. As long as no definitive body count of iraq civilians is made by our governments, then problem does not exist. We always count our own dead, but the victims of our aggression aren't worth counting. This may explain why it is so easy for super powerful and super violent states - and you now who Imean - to routinely violate the UN Charter and the Nuremberg code.
I liked the gist of the article you attached. It stipulates why polemicists like Lomborg are winning: because it is their message resonates with those who control the vast majority of wealth and power. It has nothing to to with the 'truth', but in a heterogeneous world, where vested interests are desperate to maintain the staus quo, there will always be a market for books like TSE which propound pure and utter greenwash. People want to believe in the tooth fairy, or else desperately want to shed some of the guilt they feel in being part of a rapacious economic system which ensures that 20,000 people die from chronic malnutritona every day. Alternatively, there are those who do not give a damn about this fact, but want to ensure that the economc juggernaut enriching the few at the expense of the many remains intact. I accept these facts - but this explains why I will continue to combat those who are willing to send our planet to hell in a handbasket to ensure the continuation of policies that are creating misery on a grand scale.
Lastly Theo: read my last post again. Instead of evading the issue, tell me if it is acceptable in your view to cite one study t support your argument while excluding piles of studies with opposite conclusions. As I was embarrassing Lomborg by pointing out inconvenient facts, I couldn't get him to admit that it was OK to be so selective. After all, in the final chapter of TSE he begs the reader to believe that "I have tried to present all the facts" [his words]. He didn't even come close! All he could blurt out was that "I will look into it". He'd had four years to 'look into it' before publishing his book. Theo, you are defending the indefensible.
"per, actually, if you read the part I posted,..."
you posted the findings from a committee which were subsequently overturned. The committee found him not guilty, yet you persist in suggesting that the defective functioning of the DCSD is in some way a judgement against Lomborg.
Jeff Harvey- "The decision to exonerate Lomborg by the Rasmussen government was a political one."
Thank goodness you have divine knowledge, jeff, or I would have to imagine you were telling me a flat-out lie because you didn't like their findings.
"If you are going to wade into a debate in which you know nothing, then be prepared to take a big fall."
Threats ? Does that mean you are going to tell me how wonderful a scientist you are (jeff who ?) at length again ?
Let the record show, I corrected a singularly misleading selective quotation from Wiki; perhaps you should welcome accuracy with the facts. Or are you like Lee, when any selective quotation is fine, so long as it makes your point ?
The fact that you are prepared to descend to threats makes clear all I need to know about your scientific credentials.
Toodle-pip !
per
"Its the unknowns that are the problem:"
And you have god-like knowledge of unknown species ? You won't have a reference, of course...
"This is the same trick used by ...fasciost sympathizers have used to deny the Holocaust. "
I wondered how long it would take; what you are trying to say is that Lomborg is a Nazi.
which university are you a senior professor at ?
cheers
per
That was quick
With regard to
"Since when is statistics a subfield of Political Science?"
There are several large software companies that say it is, such as SPSS....The SS stands for social sciences. The reason, of course, is that in social sciences, including political sciences, the data sucks, and to find anything you require sophisticated statistical analysis. With most physical science experiments you can make do with simple curve fitting, since in most cases you can control the system well enough that the measured quantity is a function of one, or at worst a few variables.
Per, or should I say DAVID BELL,
Wikipedia is a contributory encyclopedia. If anything needs peer-reviewing, its Wikipedia. Source watch is far better, in my view, than Wiki.
I never said Lomborg was a Nazi sympathizer, so stop putting damned words into my mouth. In fact, from what I gather he's quite liberal minded, and good for him. Just because he uses the same strategy to deny extinctions as another group uses to deny Nazi atrocities implies nothing. Why not have a go at Matt Ridley, one of Lomborg's big supporters who has used such vile analogies to describe environmental movements? But why am I debating someone whose arguments about science are at grade school level? Can you not debate science, or is it beyond you? Care to discuss ecological or evolutionary models Per or.. is it David? I really enjoy face-to-face debates with contrarians, because most of them haven't got a clue about the basics of environmental science. In front of an audience, this ignorance is exposed. Sadly, neither you, not Theo, nor Lubo has answered a single point I have made about peer-review, or about just a few examples of Lomborg's distortions. Why? Because you can't. Lomborg couldn't either, but it was harder for him because there were 100 people in the audience awaiting him to answer my specific points. But because he couldn't, and didnt even try, all he could say was "I'll look into it".
You know David, or is it per... I recall an American expert on acid rain telling me a few years ago that debating people like you is like trying to 'win a pissing match with a skunk'. His argument was that the contrarians argue that without 100% unequivocal evidence, a problem in their eyes 'does not exist'. He argued that acid rain levels in the Appalachian Mountains of Tennessee are 100-500 times low level ambient, and that it is likely that these effects would seriously harm forests. However, the dynamics of forest ecosystems are such that changes occur rapidly over very small temporal and spatial gradients; thus, to fully understand how acid rain affects forests, he'd need a billion dollar grant - never to be funded. And because he does not have the means to fully study the system, the problem therefore 'does not exist'.
You contrarian lot never cease to amaze me with your pronouncements of a deep dedication to the scientific method' when in fact you only want science that reflects your political beliefs and pre-determiend worldviews. I would have guessed this morning that you, Lubos and Theo are either far to the right politically or are libertarians, who believe in a deregulated economy, more power in corporate boardrooms and a neoliberal economic foreign policy combined with fervent support for US military intervention. Am I right guys? I see that Theo has contributed articles to libertarian web sites and Lubos calls himself the 'South Park Republican'. So much for the 'scientific method'! Its all based on your political views. Admit it.
Per,
I suggest you read the Nature review of TSE I wrote with Stuart Pimm, instead of trying vainly to put words into my mouth. And whay not use your real name? I don't hind behind a pseudonym, and to their credit Lubos and Theo don't either.
"Can you not debate science, or is it beyond you?"
"the astroturf lobbying groups and their coterie of bought-and-paid-for scientists"
"I believe his aim was fervent self-promotion."
"Theo, grow up."
I can see the cogency of the logic in your debating style.
"Yet Lomborg is an international celebrity and I am a nobody."
we agree on something !
"The MBH paper was rigorously peer-reviewed; your dislike of peer review is probably because the conclusion of the MBH paper does not blend with your own view on climate change."
Apart from your obvious mastery of telepathy, i thought I would see what your arguments actually are. Here you are arguing on peer-review. You seem to be oblivious to the fact that MBH'98 required a major corrigendum, since the methods section was utterly inadequate, and the original description of the data contained data that weren't used, didn't cite data that was, contained unjustified truncations, inadequate citations, etc., etc. That is without starting on the fact that MBH used an unusual PCA method, which was censured by NAS; that the MBH description of its statistics did not even mention that they had done an analysis (r2) which showed their analysis was crap; and that they (MBH) didn't disclose this. That MBH said that their reconstruction was robust to the absence of dendro, when they knew it wasn't.
This is your poster boy for peer-review. Strangely, when it comes to arguing science, I cannot see the fantastic god-like insight that you claim to have. Perhaps you had better tell us again how wonderful you are ?
toodle-pip!
per
"Wikipedia is a contributory encyclopedia. "
just out of interest, jeff, weren't you one of the people who brought complaints against lomborg to the dcsd ?
Isn't it a FACT that all those complaints were rejected by the DCSD, and lomborg found not guilty ?
Oh! That's right, that FACT doesn't count because it's a KKKonspiracy ! The EVIL EMPIRE is teaming up against you ! "it's a political conspiracy" "it's all them republicans!" Did you know, Jeff, that they have secret machines that can read your thoughts, and the only protection is to wrap your head in tin foil ?
I recommend you up your lithium, jeff.
toodle-pip !
per
Re: "Here you are arguing on peer-review. You seem to be oblivious to the fact that MBH'98 required a major corrigendum, since the methods section was utterly inadequate, and the original description of the data contained data that weren't used, didn't cite data that was, contained unjustified truncations, inadequate citations, etc., etc. That is without starting on the fact that MBH used an unusual PCA method, which was censured by NAS; that the MBH description of its statistics did not even mention that they had done an analysis (r2) which showed their analysis was crap; and that they (MBH) didn't disclose this. That MBH said that their reconstruction was robust to the absence of dendro, when they knew it wasn't."
Absolute BS. Where on Earth would you get such silly ideas into your head?
Toodle-pip (sounds better then per),
Have a go at Lubos. He claims to be more intelligent than 2480 of 2500 scientists (I assume he means who contributed to the IPCC 2001 draft).
Again, you fail to debate me on facts in Lomborg's book. Why? I have made a few points; I am willing to present many more blatant distortions. But you just won't bite, except for a few pathetic attempts at riducule. Why not? Again, in a face to face debate, your histrionics would not wash. Fact is, you won't debate me on most aspects of envrionmental sciwence because you can't. Lomborg tried and its just a shame you did not get a chance to see him squirm. Some guy at HAN tried and he was even worse. Its easy to ridicule people on a blog site but I think the vast majority of Tim's readers and contributors know on which side of the fence most of the scientific evidence lies.
Moreover, why is that a small band of sceptics, most of whom, are not climate scientists, seems to understand climate better than the vast majority of climate scientists? It must be because you think you are the ones with the superior intellect. Thus far we have you (not a climate scientist), Lubos, who is into string theory, and Theo, who is a journalist.
Lastly, how may times do people have to say that the MBH paper is but one piece of empirical evidence in a multi-faceted discipline with evidence supporting AGW? MBH was publsihed in 1998, a full 10 years after James hansen argued that climate cghange was udnerway. Or is this your only slender thread of hope for continued denial? What a sad lot you sceptics are.
"Absolute BS. Where on Earth would you get such silly ideas into your head?"
Dear Stephen
please be specific about what I have said that is wrong; that is the way of science. Surely it is cowardly simply to spill bile, without even saying what is "BS".
cheers
per
"Can you not debate science, or is it beyond you?"
that's funny, jeff, because I engaged on a specific example you gave about peer-review, and which is on-topic for the title of this thread. I say that your example is an excellent example of the failure of peer-review, and I gave several reasons why. I have directly contradicted you when you said that MBH'98 was "rigorously peer-reviewed"; it is blatantly obvious that there was very little that was "rigorous" about the process if they can miss so many major errors in the work.
All I hear back is the sound of silence...
or is that the sound of chickens clucking ?
go on, jeff, tell us again how wonderful a scientist you are, and how we are not fit to lick your boots :-)
toodle-pip !
per
hey Jeff
I forgot how good your mastery of scientific language is:
"Their conclusions remain unchanged"
wrong. The NAS panel specifically disagree with the claims of MBH'98; specifically, they stated that reconstructions from before 1600 have unquantifiable levels of uncertainty. This is very different from MBH'98, which claimed 99.7% certainty.
"that the last 20 years of the 20th century were very likely..."
the NAS panel did not use "very likely"; they used "plausible"
"The results literally vanquish the arguments of the denial lobby."
If only you hadn't got your words completely wrong, and if only the words didn't mean something completely different, you would be right.
Per, here is a challenge. Can you make one clear and coherent statement regarding the science on any of these issues. Save the strawmen and word games for your cheer squad. Lubos couldn't do it, can you?
jp,
if lil' FUD purveyor per can't obfuscate and mendacicize, he's got nothing.
Best,
D
"Can you make one clear and coherent statement regarding the science on any of these issues."-jp
Dear jp,
I regularly make clear and falsifiable statements, starting from my first post on this thread. My posts of June 26, 2006 10:39 AM, and June 26, 2006 09:34 AM are specific and falsifiable, and address the science.
Unlike others, my case is sufficiently strong that i do not have to resort to either threats, or to name-calling.
I will even take you on at dendrochronology, your post of June 23, 2006 12:25 PM :
"Tree rings sites are selected because they represent locations where there is a high sensitivity in the ring growth to climatic conditions."
This is circular. How do you show that there is a sensitivity to temperature ? If you have a completely random population with no response to temperature, some tree stands will show a rise, some a decrease, and some no change over a time period. This is basic statistics. If you simply select those trees with a rise (as 20th century temperature), it doesn't follow that you are selecting temperature sensitive trees.
In fact, the recent discrepancy between patterns of tree growth, and global temperatures, was a matter commented on in the NAS report.
hey- it's only science.
cheers, per :-)
"Since when is statistics a subfield of Political Science?"
"The reason, of course, is that in social sciences, including political sciences, the data sucks, and to find anything you require sophisticated statistical analysis."
As I've said before, if lecturing statistics to undergrads who are not math majors makes you a professor of statistics, then I'm a professor of statistics too. At least my students weren't in poli-sci. That's like being a professor of statistics at a dog obedience school.
"With most physical science experiments you can make do with simple curve fitting, since in most cases you can control the system well enough that the measured quantity is a function of one, or at worst a few variables."
Well, if that's the case, then laborers in said fields of physical science are in no way qualified to discuss climatology.
If you have a completely random population with no response to temperature, some tree stands will show a rise, some a decrease, and some no change over a time period. This is basic statistics. If you simply select those trees with a rise (as 20th century temperature)...hey- it's only science. [emphasis added]
This isn't science, it's arguing from false premises.
IOW, you are full of sh*t.
I'd be happy to sign you in, David, to a dendro listserv so you can argue this weak bullsh*t there. Let me know. I'll be on vacation next week.
Best,
D
Just curious, per, but could you provide more information showing that there is a completely random population with no response to temperature? I don't know dendrochronology, but that sounds nonintuitive.
On the other hand, I can fairly easily imagine that there is a set of observations that would show high sensitivity to temperature. Furthermore, I don't see that the opposite of "high sensitivity" is "random." Perhaps I'm missing something.
"This isn't science, it's arguing from false premises."
actually, what I said was correct, much tho' you hate to admit it. If you wish to disprove my basic stats, say precisely how.
vapid abuse doesn't cut it.
toodle-pip!
per
actually, what I said was correct, much tho' you hate to admit it.
It was correct in the context of your typical evidenceless assertion, nothing more. Just because you say something a buncha times doesn't make it correct.
I'd be happy to sign you in, David, to a dendro listserv so you can argue your weak bullsh*t there. Let me know. I'll be on vacation next week.
Best,
D
Dear jp,
I am sure that your head filled with materials usually found in the restrooms knows very well that what you write are pure lies.
I have not only written dozens of crystal-clear, penetrating, science-oriented articles about the climate, but my blog is also, modestly speaking, ;-) the world's #2 most authoratative blog about the climate according to Technorati (among many others).
http://technorati.com/blogs/climate
after a propagandistic blog by a large group of politicized scientists.
With per and Dano, the level of the local discussions here has increased by an order of magnitude, but due to the overcritical concentration of morons, it is still orders of magnitude below climateaudit.org, among others.
All the best
Lubos
If that's how you view #1, why should we consider it a virtue that you're #2?
Wow Lubos, your blog is much less authoritive than RealClimate. I thought you were smarter than them? How come you are getting thrashed in the authoritative stakes by William Connolley?
Per
Well done you have actually made a statement and phrased a question, you are one up on Lubos. You have written: "How do you show that there is a sensitivity to temperature ? If you have a completely random population with no response to temperature, some tree stands will show a rise, some a decrease, and some no change over a time period. This is basic statistics. If you simply select those trees with a rise (as 20th century temperature), it doesn't follow that you are selecting temperature sensitive trees."
First a comment on language, in dendrochronology the term 'Sensitivity' has a specific meaning, it is a measure of the variance in a tree ring series. When a individual tree (or chronology) shows a high amount of variance it is called Sensitive, when a series shows little annual variability it is referred to as Complacent. Of course the word sensitive can also be used in a variety of contexts. If the objective of the research is to extract a climate signal from a tree ring series it would be of no value to sample trees that were not sensitive to climate. There are many abiotic and biotic variables that influence ring growth. For example, in many stands of trees, growth is not primarily limited by a combination of climate variables but rather by competition, access to nutrients, and similar variables. In my earlier comment on dendroclimatology I was referring specifically to "site" selection. The majority of sites for dendroclimatology are selected because they represent locations where the species in question respond in a measurable way to changes in some climate variable. This is why these sites are often found near altitudinal and latitudinal treeline (potentially sensitive to temperature), in semi-arid environments (potentially sensitive to moisture) or in other exposed locations where climate plays an important role in ring growth. When you go out and core trees this becomes apparent immediately. In a complacent tree (site) there is very little variance in the ring growth while in a sensitive tree (site) there is considerable variance in ring widths. So how "do you show that there is a sensitivity to temperature", you measure it by constructing a chronology from a group of trees at a site and examining the correlation between the ring series and a range of climate variables. At a good site for dendroclimatology there will individual trees with a high sensitivity, a strong correlation between the trees growth patterns within a stand and a chronology that has a significant correlation with a climate variable(s). There is nothing random about site selection. If I am sampling trees to construct a chronology of snow avalanches or flooding I go to those environments. If I am attempting to produce a reconstruction of a climate variable I will select locations where the trees are sensitive to those variables.
This is of course basic dendroclimatology, I would start by reading Fritts classic text on Tree-Rings and Climate, and then buy a corer and get out in the field. After you have cored a few hundred trees across a variety of locations and examined their ring patterns you will begin to appreciate how site selection is an important part of this process. After a few thousand trees you may actually learn to like it.
And to Lubos I am certain that your APT committee will be very impressed by your Technorati rating.
Well, z, climate data is one of those areas where you can't control the system, so you do need sophisticated statistics, string theory, on the other hand, has no data. Most physical sciences are somewhere in the middle.
When I was in grad school, we had a killer comp question: Explain the universe, give two examples, little did I think that my fellow students would take that seriously enough to come up with 10^somegodawfulnumber universes. If we look hard enough we may even find the one with Ringworld in it, although it is a mighty strange part of the landscape.
"Just curious, per, but could you provide more information showing that there is a completely random population with no response to temperature? "
Dear Davis
I am not making that case; I am simply setting out the difficulties in showing that you have a tree group that has a linear response to temperature.
If you set out with a wholly random group, some will go up, some will go down, some will stay the same. If you select only the trees which are going up, and then argue that they are temperature sensitive, there is a circularity in your argument.
It is well known that some trees in some positions are not responsive to temperature. What i didn't appreciate is that when some researchers look for "temperature-sensitive" tree sites, they don't bother archiving the data for the non-temperature sensitive sites.
While it is a nice and intuitive idea that some tree sites are temperature sensitive, it is kind of important to test this idea. The NRC report has extensive discussion of "the divergence" problem, whereby many tree sites fail to show the increased temperature seen in thermometer records post-1980. This calls into question the use of trees as a temperature record.
cheers,
per
Too much credit for Ken Ring to give Larry Niven's creation to him.
"At a good site for dendroclimatology there will individual trees with a high sensitivity, a strong correlation between the trees growth patterns within a stand and a chronology that has a significant correlation with a climate variable(s). "
dear jp
it seems you don't understand what I am saying. You are talking about selection post-hoc.
It sounds to me like that are stands where there is poor correlation between trees for growth; where there isn't a significant correlation with a climate variable. It sounds in other words like a series of samplings of random data, where you discard the "bad ones", and end up "finding" one with a good response to temperature.
cheers
per
Per
In order to archive the data you first need to travel to the site, sample (core) the trees, store and transport the cores back to the lab, mount and surface the cores, measure the ring widths, identify missing rings, cross-date different cores, reject and accept cores for inclusion in the chronology (quality control), construct the chronology and then begin the statistical analyses. This process is time consuming and expensive. When you are in the field and you are sampling trees if you see the ring series are complacent, you save your money and time and you move on to another site.
That said, if you are looking for tree-ring chronologies that are likely to have less sensitivity there are many chronologies available from the ITRDB that have a poor climatic signal. Alternatively you could search for chronologies that were gathered for other purposes (e.g. dating control of geological events such as floods and mass movements) or sample your own.
The NRC report has identified what has been known in the paleoclimatic community for a long time, it is a difficult business to extract a climate record from a tree-ring chronology. That is why it is but one piece in the paleoclimate puzzle.
Oh I don't know Hans, I rather think of Ringworld as an imaginary place for picaresque journeys through a fantasy landscape full of magic, dangers and grotesque creatures. A good fit for our Ken.
The NRC report has identified what has been known in the paleoclimatic community for a long time, it is a difficult business to extract a climate record from a tree-ring chronology. That is why it is but one piece in the paleoclimate puzzle.
Hence multiproxy chronologies.
It's a good idea, which is why MBH98 was totemized, in order to kill the good idea. Can't have a free market of ideas, you know.
Per knows, jp, what the coring and dating procedure is. He's just dissembling, obfuscating, and purveying his brand of FUD (nobody here is buying).
Best,
D
"When you are in the field and you are sampling trees if you see the ring series are complacent, you save your money and time and you move on to another site."
like I said, post-hoc selection of the data that "fits" what you want it to.
"The NRC report has identified what has been known in the paleoclimatic community for a long time, it is a difficult business to extract a climate record from a tree-ring chronology."
This has been discussed in some detail at climateaudit. The NAS report puts further severe constraints on the use of trees as a valid proxy for temperature.
toodle-pip !
per
Dano-"It's a good idea, which is why MBH98 was totemized..."
Unfortunately for you, it was the IPCC who totemised MBH'98. They got Mann to head up the section which lionised his own work. It was put "front and centre" of the publicity, and the summary for policymakers of the TAR.
That is why it is so unfortunate that this paper had major errors in its methods and data; it features unusual PCA which the NAS panel censured; they calculated adverse statistical measures, and simply withheld the information; their statistical analysis was censured by the NAS panel; and they made statements about the robustness of their reconstruction to the absence of tree proxies, which do not hold up.
Yes, Dano, science is a place where it is essential to have free access to methodology; MBH have refused this, and it is easy to see why. And still you support them.
bemused, per
Per
Well I gave you chance but that refusal to learn is just engrained. Here is a demonstration of your logic. A pharmacutical company is funding a drug trial for a disease that affects a small percentage of the population. Doctor A suggests they administer the drug to a ramdomly selected sample of the population to test its efficacy. Doctor B suggests it would be more effective to stratify the sample and actually test the drug on a random sample of the population that is afflicted or at high risk of the disease. What would the smart company do? What would Per do?
Following the trial, the company announces great success. However, an immediate audit is ordered. Per declares the results are invalid because they have found what they we looking for!
per might want to talk with Dr. Lott.
like I said, post-hoc selection of the data that "fits" what you want it to.
I'd be happy to sign you in, David, to a dendro listserv so you can argue your weak bullsh*t...er...heroic Lomborgian overthrowing of a discipline you haven't studied++ there. Let me know. I'll be on vacation next week.
Best,
D
++ A strike tag is so much more appealing here...
dear jp
are you really a practicing scientist ? Do you really fail to understand what post-hoc data selection is, and why it is so very problematic ?
You are selecting only those trees which show a correlation with temperature. You are then claiming that they are temperature-sensitive- but you have already selected them on that basis ! The temperature sensitivity is a circular argument.
To be quite clear, if any pharma company submitted a study where they did post-hoc data selection, they might well be liable for criminal prosecution.
Per
You have demonstrated: (a) you have no knowledge of paleoclimate, (b) you cannot read, and (c) your time has past.
The world moves on, the audit fades to black....
"(b) you cannot read"
? you are advocating post-hoc data selection; that is what you wrote. I explained exactly why that is problematic.
You have not engaged with that argument at all, nor attempted to explain why it does not apply. All i get is nebulous smears; and they have to be pretty nebulous, because your specific claims have a habit of coming unstuck.
oh well, it is Doltoid...
per !
Do you really fail to understand what post-hoc data selection is, and why it is so very problematic ?
I'd be happy to sign you in, lil' per, to a dendro listserv so you can argue your Lomborgian overthrowing of a discipline you haven't studied there.
Let me know. I'll be on vacation next week.
Best,
D
Where are you going? I can recommend the Gaspe peninsula in Canada, you can help to find the lost site!
"I'd be happy to sign you in,..."
see Dano, that's the thing about science; it is specific and falsifiable. You could have leveraged your (no doubt) phenomenal knowledge in botany, and cited a reference, given a specific example; that would be specific and falsifiable.
But instead, we get a vapid proclamation from Mount Dano, telling us that you know it all, and there is a listserv where I may humbly learn, before prostrating myself at your feet. Specific ? No. Falsifiable ? No.
Obfuscatory ? Yes. And who is the lil' bot who just loves to carp on about "obfuscatory, mendacisationising" posts? Step forward Dano.
forever in your gratitude
per
Dano, I think that was per's idea of a polite refusal. I wonder would per's line of argument work with a traffic cop?
"I really wasn't speeding officer."
"Radar says you were, sir."
"But that's a speed-sensitive instrument! You're trying to measure speed with a speed-sensitive instrument! That's circular reasoning."
"Uh, you mean if I just looked at, say, a lamp-post or something..."
"...You wouldn't have any evidence that I was moving at all! Exactly! Toodle-pip Officer!"
"...science-oriented articles"
Full of truthiness no doubt.
Dano's tricks:
The answer is:
"On the internet"
"somewhere in this 300+ page document"("linky")
"in this listserv"
"in your local university library"
Dano never quotes, he always refers.
...And then he is off.
Hans- spot on !
Kevin Donoghue:
it is clear that I can have no argument with any proxy which robustly measures temperature; but what is at issue is whether the proxy does measure temperature.
So here is a question; how do you demonstrate (prove) that trees measure temperature ? Tell me how you do the experiment.
If you can look at the environment of specific trees, identify the site as temperature sensitive, and then lo-and-behold ! you have a testable hypothesis; you test the trees you specify, and the hypothesis stands or fails. This is not what is done.
Instead, you take trees, correlate them with temperature, throw away the results you don't like (the ones which don't change, or which go down), and you are left with the ones which go up (are "temperature sensitive").
Can you really not see why this is problematic ?
yours
per
"Where are you going? I can recommend the Gaspe peninsula in Canada, you can help to find the lost site!"
I don't know why Hans Erren has any interest in trying to suggest that global warming isn't happening because he thinks we shouldn't care what happens after we all die.
see Dano, that's the thing about science; it is specific and falsifiable. You could have leveraged your...etc.
Shorter per:
tap dance away from being called on my bullsh*t, quick!
Dano never quotes, he always refers.
This from the guy who forced me to coin the phrase 'ploppedness'. Gimme a f'n break.
The fact is, folks, that the bots are energized by some FUD phrases that somebody made for them.
They'll lose their energy soon and all can go on. Let us note that their attempt to hijack the public dialogue is not working. Look at the headlines, lil' quibbling bots.
Best,
D
"Too much credit for Ken Ring to give Larry Niven's creation to him."
Inventive as Dr. Niven is, I doubt he could ever have come up with a planet wth an orbital velocity greater than the speed of light. (Ring-Earth, after all, is one light year from the sun but still manages one revolution per year).
per: Instead, you take trees, correlate them with temperature, throw away the results you don't like (the ones which don't change, or which go down), and you are left with the ones which go up (are "temperature sensitive").
No, that's not how it is done, at least not according to jp's account above. The aim is to identify trees which show high variance. That makes sense whether the planet is getting warmer or colder. If as you say researchers simply "throw away the results they don't like" that's just fraud. Sure scientists cheat from time to time but if you really think it is common practice than you may as well dismiss all research that you haven't done yourself.
Kevin
As Per has clearly demonstrated, he has no interest in learning only in disinformation. The assessment by Dano (and others) of Pers (David Bells) character is accurate. I suggest we starve the troll.
kevin, jp, this is a direct cite from jp.
"So how "do you show that there is a sensitivity to temperature", you measure it by constructing a chronology from a group of trees at a site and examining the correlation between the ring series and a range of climate variables. At a good site for dendroclimatology there will individual trees with a high sensitivity, a strong correlation between the trees growth patterns within a stand and a chronology that has a significant correlation with a climate variable(s). "
as far as I can see, it doesn't say that the only cut is pre-data, and selection for high variance. It specifically defines a good site as one with a significant correlation with a climate variable; this is post-hoc analysis. By definition, sites without that correlation aren't good.
If you think that bad scientific practice is uncommon, or isn't engaged in throughout the scientific enterprise, you are wrong. Scientists make mistakes all the time; the beauty of the scientific enterprise is in making your procedures open, free and honest discussion of what you do, and replication.
Just for instance:
http://www.cs.princeton.edu/~ken/Langmuir/langmuir.htm
It is amusing to see who is running from free and open discussion.
per !
"As Per has clearly demonstrated, he has no interest in learning..."
well, jp, I am prepared to learn. If your analysis is not post-hoc, explain to me why.
But perhaps we can agree; that what you have described is post-hoc analysis.
yours
per
per: It specifically defines a good site as one with a significant correlation with a climate variable; this is post-hoc analysis.
No it isn't. There is normally a strong correlation between the speed of a car and the speedometer reading. If there isn't, it certainly isn't a good speedometer.
See Dano that's your problem, showing your credentials will reveal your identity.
Keep on swearing, I am not impressed,
Having perused a number of AGW sites, pro and con, I am struck by the tremendous difference in quality of the argumentation presented by each side.
The skeptics are, by and large, wont to focus on the science, and specific critique thereof. The proponents on the other hand, most frequently offer little more than ad hominem in its various and asundry forms. This thread is no exception.
Do they no longer teach fundamentals of formal logic in schools? Has no one heard that 'Because a climate scientist says so' is not a valid argument? That 'who are you to ask that question' is not an answer to that question?
Dear Kevin
you just said "no it isn't". Here is the direct cite from jp.
"At a good site for dendroclimatology there will individual trees with a high sensitivity, a strong correlation between the trees growth patterns within a stand and a chronology that has a significant correlation with a climate variable(s). "
I have simply paraphrased jp; if you can explain where I have misunderstood, I will be grateful. I have gone by what jp said; if you can explain that the reality is entirely different, that is fair enough.
But this is post-hoc; it is only once you have excluded the sites with a bad correlation, that you are left with the sites with a good correlation to temperature. Entirely post-hoc.
what am I missing ?
yours, per
This is hilarious given that skeptics continuously accuse the community of climatologists of being guilty of scientific fraud. They say this in the press, to Congressional committees, etc etc.
If you want science, go read Real Climate's excellent summary papers on what's known about global warming. These are written by some of the leading climate experts in the world.
However, my guess is that you're just trolling and could care less about the state of the science...
Don Baccus,
"This is hilarious given that skeptics continuously accuse the community of climatologists of being guilty of scientific fraud."
That is an example of ad hominem tu quoque.
"If you want science, go read Real Climate's excellent summary papers on what's known about global warming. These are written by some of the leading climate experts in the world."
This is an example of a variation of ad hominem called ad verecundiam.
Why the apparently irresistable urge to include fallacious reference to 'leading climate experts'? Who cares if they consider themselves 'leading' whatever? Leaders are often dead wrong. And frankly, in a field as broad as 'climate science', nobody is a 'leader' in every aspect of his own work, much less in the field as a whole. Appeal to authority is fallacious. Are their methods and conclusions correct? That is what matters.
"However, my guess is that you're just trolling and could care less about the state of the science..."
And that is just pure 'ol ad hominem.
Thanks for demonstrating exactly what I'm talking about.
JJ
you can determine leaders; the ones with the peer-reviewed publications, which whittles out a lot of the skeptics
So, I post an observation that the majority of the pro-AGW arguments are little more than ad hominem, and the first two 'contrary' responses are 100% ad hominem.
Who will make it three? Step right up and throw another irrelevant fallacy on the pile! Dont miss out on your opportunity to be among the first ... i.e. a 'leader'.
LOL.
From Von Storch, Zorita and Gonzalez-Raucen
4) With respect to methods, the committee is showing reservations concerning the methodology of Mann et al.. The committee notes explicitly on pages 91 and 111 that the method has no validation (CE) skill significantly different from zero. In the past, however, it has always been claimed that the method has a significant nonzero validation skill. Methods without a validation skill are usually considered USELESS.
It's an "ad hominem" attack to point out that in science, the papers in peer-reviewed journals shows the validity of the research? Also, you are whining that everything is an ad hom attack, even someone pointing you to papers on realclimate.org. How silly.
PS -- I agree with the von Storch analysis, too bad the Mc&Mc are just grasping, reedy twits (yes -- that's an ad hom :-)
According to Lubos:
"Sorry to say, but the answer is .. my higher intelligence and physics background than 2480 of these 2500 people."
Would that be the same higher intelligence that enabled you to not realize that "Predict your Climate" relies on any artificially chosen mean value for the forecast temperature whereas the hockeystick reconstruction doesn't? What an enabling higher intelligence you have.
"and former mineral consultants (who was the #1 mathematician in Canada, by the way)"
Poor Canada.
Having perused a number of AGW sites, pro and con, I am struck by the tremendous difference in quality of the argumentation presented by each side.
The skeptics are, by and large, wont to focus on the science, and specific critique thereof. The proponents on the other hand, most frequently offer little more than ad hominem in its various and asundry forms. This thread is no exception.
If that's your perception, your either ignorant, blind, stupid or stoned.
The best place to go for the science is the scientific literature. This strongly supports the global warmers.
The next best place to go for a discussion of the science is the IPCC reports. These strongly support the global warmers.
According to Lubos:
"the statistical significance of all results before 1600 is zero .... the panel has announced that all dendro conclusions before 1100 are statistically worthless"
Please try to be consistent within the one paragraph Lubos. It may affect your credibility which is very impotant to all of us.
CC,
"It's an 'ad hominem' attack to point out that in science, the papers in peer-reviewed journals shows the validity of the research?"
A. That is not what you did. Your comment was nothing more than an ad hominem against opposing researchers, not a scientific rebuttal of any research. And yes, attacking the researcher is ad hominem.
B. Yes, swinging 'peer review' around like a trump card is also fallacious. That research appears in a peer reviewed journal does not 'validate' it. Note that one of the fundamental functions of peer reviewed journal articles is to refute previously published peer reviewed journal articles. Similarly, that research does not appear in a peer reviewed journal does not invalidate it.
Peer review, performed properly (and often it is not), is a useful convenience, not a magical truth filter. When properly performed, the peer review process has inevitable, demonstrable, and unquantified Type I and Type II error. Often, it is also susceptible to bias. It cannot be legitmately used to summarily dismiss a postion, much less a person (or class of persons, as you attempted).
"Also, you are whining that everything is an ad hom attack,"
No, I am not. Nice hyperbole, though. Complements the straw man you create next:
"... even someone pointing you to papers on realclimate.org."
Note that I identified the ad hominem in that portion of the post as the inclusion of the irrelevant 'leading climate experts' crap, not the offered reference to the RC website. Intentional misstatement of the other's position is yet another fine example of the generally low quality of the argumentation dished up by the AGW proponents. Thanks.
Earlier on this thread, you made several 'appeal to authority' fallacious comments. Then you chastised Lubos for doing it. Then you did it some more. Then you chastised M&M for *not* commenting outside their field of knowledge. And then you called *other* people 'pseudo-intellectual twits'. Interesting chain of events, that.
JJ
per,
You assert that you are merely paraphrasing jp's comment, but jp clearly doesn't agree. Don't you find it little awkward to have the original author rejecting your paraphrase? Any reader who is interested can compare his account with yours and confirm that they just don't match. Nowhere does jp say anything to underpin this (your) description:
jp defines sensitivity differently from you:
jp describes a procedure which, diligently followed, gives the data a fair chance to show a falling trend in temperatures. You describe a procedure which can give only one result.
You're not paraphrasing.
Now, you ask what it is you are missing. That's never an easy question to answer, even when one knows a great deal about the person who is asking. But I think you provide a clue when you say: "it is only once you have excluded the sites with a bad correlation, that you are left with the sites with a good correlation to temperature." My best guess is that you are inferring that a site with a good correlation to temperature won't provide evidence of falling temperatures. That's not a valid inference. Another possibility is that you have read about the pitfalls of extrapolation and you believe that researchers have indeed tumbled. Maybe they have, but jp's account doesn't suggest that. Unless you explain your theory in more detail I don't think there is much point in my trying to offer a critique.
kevin
I accept that sensitivity/ complacency refers to the variability in ring width/whatever; tell me what phrase you wish to use to convey that there is a correlation between tree growth and temperature if you find "temperature sensitivity" ambiguous, and I can use it. I have quoted directly from jp, and I have made clear this is the bit which I am paraphrasing;
"So how "do you show that there is a sensitivity to temperature", you measure it by constructing a chronology from a group of trees at a site and examining the correlation between the ring series and a range of climate variables. At a good site for dendroclimatology there will individual trees with a high sensitivity, a strong correlation between the trees growth patterns within a stand and a chronology that has a significant correlation with a climate variable(s). "
These are jp's words. At good sites, there is a significant correlation with temperature. So what sort of site gives a poor correlation with temperature ? Does this description not imply the presence of some sites where there is a lack of correlation with a climate variable, or poor correlation between tree growth patterns ?
jp has described what appears to be post-hoc analysis. If his description is wrong, or if there is a different process involved, I am sure jp can tell us. Likewise, if JP has a tantrum, and throws his toys out of the pram simply because there is a legitimate criticism of what he has said, then that does not say much for his ability to explain his research.
yours
per
err, JJ, science by peer-review in journals seems to be the best bet. It was good enough for Einstein, it's good enough for everyone. Jeez, can one imagine Einstein trying to get through the noise of a blog? HAHA. And having Steve McIntyre & his right-wing lackeys put him down ad infinitum for a simple mistake he may have made. Sorry, but blogs are good for entertainment; leave the science to peer-reviews not reviews by "nanny_govt_sucks" & that ilk.
Einstein wasn't peer reviewed. ('Annalen der Physik' had only editors in the early years)
well said, JJ:
"Earlier on this thread, you made several 'appeal to authority' fallacious comments. Then you chastised Lubos for doing it. Then you did it some more. Then you chastised M&M for not commenting outside their field of knowledge. And then you called other people 'pseudo-intellectual twits'. Interesting chain of events, that."
CC has managed "twits", "right-wing lackeys", "liar", so he gets an A+ for abuse; but it is amazing how short he is on science and logic.
Then he comes onto a blog to make comments, and then starts complaining that you can only discuss science in the peer-reviewed literature. Why then is he on a blog discussing a scientific point ?
amusing
per
I've been away a couple of days doing research. In that time I have had a major rethink about Per's comments, and his uncanny ability to show how much of an ability he has to discuss scientific issues across a range of disciplines with immense depth and clarity. His support for Bjorn Lomborg has impressed me too, and its finally dawned on me that university study is not necessary to attain a complete spectrum of wisdom in a suite of fields far removed from your own professional area. Per, I yield to you. Lubos should also realize that he could have saved about 10 years or more of university time and a lot of money when studying string theory; why waste this time if all you need is to be infinitely intelligent (like Per) and thus dispense with the characters of all of those with whom you disagree?
Per, you are therefore correct in everything you say. I defer to you. During my BSc programme at Liverpool University and thereafter in three post-docs and in my current position as a senior scientist I have studied and researched population ecology, but now I know that Per is an expert in this broad discpline. He can discuss, in detail, any of the following: Nicholson-Bailey, Thompson and Lotka-Volterra models; functional responses types I-III; k-factor analysis; factors affecting the evolution of semel and iteroparous reproductive strategies, including the r- and K selection continuum; factors promoting species co-existence within defined feeding guilds; the Terborgh-Soule models of exponential decay in predicting extinction rates; a suite of hypotheses, including (in the invasive species literature), the enemy release, evolution of increased competitive ability and novel weapons hyopotheses; in community ecology the enemy-free space hypothesis and the diversity-stability hypothesis; the role of ecophysiological constraints in studying multitrophic interactions and community structure and function; neutral models in determining niche breadth the outcome of interspecific competition; linking above- and belowground community level processes via primary and secondary plant metabolites; constitutive and induced defences in plants and animals; the importance of biotic and abiotic forces in successional gradients et al.
I expect that Bjorn Lomborg is smilarly qualified, based on the fact that he studied political science at Aarhus University. Although its likely that his study covered very few or none of the areas I mentioned above, Per's theory is still probably correct: being smart means you can master everything with no need for persky university study. So my advice to Tim, Carl, Dano, Eli, and others is this: Per's widsom knows no boundries. I can't wait to discuss the invasive ecology literature with him, and then swith to an in-depth discussion of endocrinological factors regulating ontogeny in parasitic organisms, perhaps finishing up on top-down and bottom-up regulation in ecological communities, and the role of structural heterogeneity in generating stability. I am sure that he has read all of the relevant literature by Elton, Gleason, Hutchinson, Hairston and others. On top of that, I'd be simply delighted to know what he thinks about the Lack optimal clutch size model.
"I post an observation that the majority of the pro-AGW arguments are little more than ad hominem"
Perhaps that would appear more scientific and less ad hominem if you accompanied it with a statistical analysis of the pro and anti AGW sites.
"and former mineral consultants (who was the #1 mathematician in Canada, by the way)"
I myself am the best statistician in the world; however no other statistician is sufficiently sophisticated to understand the methodology which brought me to this conclusion.
CC,
"err,"
An unusually appropriate word with which to begin your response. I commend your choice. :)
"JJ, science by peer-review in journals seems to be the best bet."
Science by betting is a contradiction in terms. Peer review *is* a bet, and one with unknown odds. It is thus a useful convenience, but it is not definitive. And more to the point, it is certainly not an excuse for summarily dismissing the positions of anyone.
"It was good enough for Einstein, it's good enough for everyone."
More fallacious reasoning. Appeal to authority. Appeal to tradition. Both illogical - not scientific.
"Jeez, can one imagine Einstein trying to get through the noise of a blog?"
Yeah. I can imagine what guys like you would have said about him, when he came up with General Relativity:
*This guy is a friggin postal clerk. He thinks we should throw out the esteemed work of ISAAC NEWTON, whose theories of physics have been supported by hundreds of derivative works in peer reviewed journals? That bozo-haired clown should stick to selling stamps and let the REAL Physicists tell us what is what. HAHA.*
But now, you invoke his name on the other side of that particualr fallacy. Haha, I guess.
"And having Steve McIntyre & his right-wing lackeys put him down ad infinitum for a simple mistake he may have made."
The mistakes Mann made were not simple. They were fairly involved, such that it took someone with specific knowledge and experience in the area of statistics to point it out. Mistakes that made it into peer reviewed journals more than once. And the political diatribes you persist with are more ad hominem.
"Sorry, but blogs are good for entertainment;"
Other blogs have much higher science content. This one is mostly political polemics, pretending to be science. Belies the promise of the URL. If only this were www.political-hacks-pretending-to-be-scientific-blogs.com ...
"... leave the science to peer-reviews ..."
The content of some other blogs is at least as reliable as most peer review. The content of most AGW proponents' posts is less so.
"...not reviews by 'nannygovtsucks' & that ilk."
and Carl Christensen and his? We leave them to what?
JJ
JJ: "The content of some other blogs is at least as reliable as most peer review."
This boy's going to single-handedly revolutionize science...
per: tell me what phrase you wish to use to convey that there is a correlation between tree growth and temperature
I see nothing wrong with referring to it as the correlation between tree growth and temperature. If that's too long-winded I guess you could call it "the correlation" or Corr(gro, temp) if it's unclear which variables you have in mind.
jp has described what appears to be post-hoc analysis.
It doesn't appear so to me. Sure there are sites where the correlation is poor. They will provide no useful information, just as the traffic cop will get no useful information about the speed of my car by studying the lamp-post. That's why he uses a radar speed-gun, with a very high Corr(speed, reading). Consider what might be done if there is doubt about the reliability of a batch of radar systems. They could be tested by comparing their readings with a sample of cars whose speed is calculated using a stop-watch and two landmarks a suitable distance apart. Any radar guns showing a low Corr(speed, reading) would be returned to the manufacturer and any data gathered using them would be deemed unfit for use as evidence. The procedure described by jp is analogous.
Selecting appropriate proxies for temperature by studying the data is not post-hoc analysis. It is what any sensible researcher would do.
"His support for Bjorn Lomborg has impressed me..."
Dear Jeff, read again. Did I support BL, or did I merely point out that a particular selective quotation was extremely misleading, and that he was exonerated by the DCSD ? The latter is a fact, and I can scarcely imagine that you would wish to support deception about BL ?
"During my BSc programme at Liverpool University and thereafter in three post-docs and in my current position as a senior scientist... "
well, in all that time, it is a shame you didn't learn how to argue coherently. Blowing your own trumpet doesn't advance your case. Insulting other people doesn't advance your case.
As you know, I have made no specialist claim to knowledge. I welcome better knowledge, and strive to learn. I am prepared to ask questions.
If you cannot answer simple and relevant questions, don't take it out on me.
toodle-pip !
per
The content of some other blogs is at least as reliable as most peer review. The content of most AGW proponents' posts is less so.
Suuuuuuuure.
Sure pal.
Best to commence ignorage.++
Best,
D
++ Let me guess: that's ad hom or not scientific or some fallacy, huh?
dear kevin
the trees with high correlation are defined as such only after you have done the analysis; this is post-hoc by definition.
"Any radar guns showing a low Corr(speed, reading) would be returned to the manufacturer and any data gathered using them would be deemed unfit for use as evidence. The procedure described by jp is analogous.
Selecting appropriate proxies for temperature by studying the data is not post-hoc analysis. It is what any sensible researcher would do."
Ok, here is a question for you to see if you are a reasonable researcher. You have got four stands of trees from the same area, and which have been suggested by prior considerations to show correlation with temperature, and you core samples for each of the four. If three stands show no (or an inverse) correlation with the temperature record, and one shows a reasonable correlation, can you simply use the one stand as showing a correlation with temperature, and discard the other three ? Have you then shown that this stand of these trees are sensitive to temperature, and record the temperature ?
I look forward to your reply.
In the meantime, I note that thermometers, and speed guns, can be repetitively tested, and calibrated. There is only one temperature record for a given stand of trees.
There is a reasonable belief that if you assemble the bits required for a speed camera/ thermometer, then given appropriate quality control criteria (such as everything screwed in, etc), that a speed camera or thermometer will perform as expected, and that a very high percentage (90+%) will function as a speed camera or thermometer. With trees, there is apparently no way of identifying those stands which will have a temperature response; the % that will show correlation with temperature is unknown, and almost certainly biased by the tree stands that are simply not archived or analysed (strangely, complacency seems an appropriate choice of word here).
I do not think your analogy to thermometers/ speed cameras is particularly insightful.
yours, per
Ok, here is a question for you to see if you are a reasonable researcher...[h]ave you then shown that this stand of these trees are sensitive to temperature, and record the temperature ?
I'd be happy to sign you in, David, to a dendro listserv so you can try to argue your weak FUD there.
Let me know. I'll be on vacation next week.
Best,
D
"Perhaps you had better tell us again how wonderful you are ?"
just in case you hadn't noticed, jeff, I posted this twice before, and you still told us what a senior scientist you were.
Such a very senior scientist, and yet; you got the words wrong from the NAS report. Such a very senior scientist; yet you are not prepared to argue your contention that MBH is a sparkling example of peer-review.
per
Dano- "I'd be happy to ..."
do anything but answer the question ? A simple yes or no would suffice :-)
"The answer is: "On the internet" "somewhere in this 300+ page document"("linky") "in this listserv" "in your local university library""
Didn't Hans just get it right ?
yours, per
Shorter per:
Hand-wave away from being called on my bullsh*t, quick!
Best,
D
Dano,
"Let me guess: that's ad hom or not scientific or some fallacy, huh?"
No, that is not a fallacy. It is just chicken $#!^. Running away from a dispute instead of engaging on the merits. Very similar to how you are dealing with Per's questions, and descriptive of your entire participation on this thread.
Happy to sign him up for a Dendro listserv? If his 'FUD' is as weak as you claim (over your shoulder, while beating a hasty retreat), then why can you not effectively (read: scientifically) respond to it here? Is there something about the rational defense of your position on tree ring/temperature methodology that only works when you have people shaking pom-poms in the background?
Or do you just not know enough about the subject to justify what you believe about the subject? Its OK to admit that. Nobody knows everything.
JJ
Lubos advised Jeff Harvey:
"besides reading my postings, it may also be a good idea for you to read the report."
It may also be a good idea for Lubos to take his own advice.
per,
Your question suggests to me a possible source of confusion. What we need to keep in mind here is the purpose of the research. Your objection seems to be predicated on the assumption that what we are discussing here is hypothesis testing as taught in introductory statistics courses. If for example a researcher is testing the hypothesis that a particular species of tree is sensitive to temperature, or that its sensitivity depends on a particular set of variables, then of course it would be inexcusable to make lots of observations and throw out the ones that don't fit.
That's not the case being discussed here. I refer you to jp's explanation:
What we are talking about here is the construction of a proxy variable - a common enough task in science. In that context jp's approach seems sensible to me. Obviously you disagree but you haven't explained why.
...the % [of trees] that will show correlation with temperature is unknown, and almost certainly biased by the tree stands that are simply not archived or analysed....
Here you are saying that a variable is both unknown and probably biased. That makes no sense at all. Perhaps you mean that the true correlation is unknown - as true correlations invariably are - while the estimates are biased. For all I know that may be true, but you shouldn't complain about jp losing patience with you if you won't take the trouble to present a coherent case. In any event it is only trees which actually do show a correlation with temperature which are of interest. Whether they are common or not isn't especially relevant.
Kevin,
"Obviously you disagree but you haven't explained why."
He has, but you havent grasped it yet. It is a bit subtle.
"In any event it is only trees which actually do show a correlation with temperature which are of interest."
True, but incomplete. It is not trees which show a correlation to temp that are of interest. It is the trees that show a response to temp that are of interest. The latter being a subset of the former.
Correlation is not sufficient. There must be causation. Per's question boils down to: How does this apparent post-hoc selection method (which certainly will find correlation, as it preferentially tosses everything else) identify causation?
WRT the counterexamples that you provided (speed guns, etc) the answer is that such things are tested. One might test trees for response in the same manner, but that does not appear to have been done. Or has it? That is the question.
JJ
dear kevin
my congratulations on maintaining a civil dialogue.
You are of course correct when saying that I cannot say that something is both unknown and biased. I will stick with unknown, but it pains me to see so many people flagrantly burying/ not analysing perfectly good data, and that is a bias.
JJ's point is good. The point of comparing growth records with temperature is not just to demonstrate a correlation, but then to suggest that this is causation, and that therefore, the whole of the growth record for the rest of the trees shows similar causation, and hence temperature. Given that you have tossed the non-responders, how do you know that you have a temperature response ?
"If the objective of the research is to extract a climate signal from a tree ring series it would be of no value to sample trees that were not sensitive to climate."
That may be jp's quote, but it presupposes that there is a climate signal there that can be extracted. If there is no such climate (or specifically, temperature) signal there, then excluding the non-responding stands simply gives you a biased sample.
Let me be absolutely clear that I have minimal knowledge of botany, and even statistics. It may well be (as JJ says) that these questions have been answered in a significant way, and I would be delighted to find out about it; whatever the answer is.
yours
per
JJ and per: the following citation is one of a series of tree ring studies in Utah Arizona and Wyoming, that have some interest. Most of the sites studied (including a later study on Bighorn) show no or minimal correlation between tree growth and temperature, but very strong correlations between growth and drought/floods over the last 1,000 years (NAS please note). Unfortunately while there are times and places when larger precipitation and warmer temperatures coincide, at other times and sites they do not (eg Bighorn). Using the radar speed gun analogy, what we have here is a radar gun that does not match the MBH gun's readings. Which one is defective? We have more reason to reject the MBH batch which post-NAS is valid only back to 1600 than to reject these with their impressive continuity back to 1000. The Jackson studies seem worthy of attention by Jeff and CC.
NSF-DEB-9815500- FINAL REPORT, COLLABORATIVE RESEARCH, "LATE
HOLOCENE EXPANSION OF UTAH JUNIPER IN WYOMING: A MODELING
SYSTEM FOR STUDYING ECOLOGY OF NATURAL INVASIONS",
Steve Jackson (University of Wyoming) and Julio Betancourt (University of
Arizona).
per / JJ,
Certainly it is well to remember that correlation does not reveal causation. That warning is drummed into the head of every stats student and with good reason. But it is also important to be aware that it doesn't always matter. For example, let's imagine we find a very strong correlation between obesity and mortality. Is this because obesity is bad for the health or because those who are on their last legs don't exercise? For a doctor the direction of causation is important; but for a life assurance company it doesn't matter in the least. The correlation tells us that obesity is a good proxy for mortality risk and obesity is observable whereas (ex-ante) mortality risk is not.
I think I now have a fair idea of what per's concern is. At all events I will give it one last shot, since it relates to statistics not botany (of which I know nowt). Suppose we have a large table of numbers, consisting of hundreds or maybe thousands of columns. The first column represents temperature and contains 100 numbers corresponding to the years 1901-2000. Each of the other columns represents a tree and contains 200 numbers which may or may not track temperature closely for the period 1801-2000. The optimists assert that some unknown proportion of the columns are a good proxy for temperature, but the only way to identify them is by statistical methods. The table is all we have. (In practice, as Tim Curtin's comment indicates, some can be ruled out on botanical grounds; but never mind that.) The pessimists assert that picking columns by calculating correlations will give spurious results. How are we to know who is right?
Statisticians have a strong predisposition to regard data as worthless until there is strong evidence to the contrary. One simple approach would be to calculate all correlations with temperature for 1901-2000 and identify the best performers, then repeat the process for the two sub-periods 1901-1950 and 1951-2000. If the same trees mostly emerge as winners in both sub-periods that's not likely to be a fluke. If there isn't a goodly overlap between the two sets of winners then the verdict goes to the pessimists. Other tests can be used to compare the "temperatures" reported by the winning trees for the period 1801-1900. If their high correlations with 20th century temperatures are spurious it is likely that the "histories" they report for the 19th century will be wildly divergent.
There are many tests which can be carried out in cases like this, some simple and some horribly complicated. If you want to know more then I can do no better than emulate Dano and suggest that you look in a good library. I quite liked The Analysis of Time Series by Christopher Chatfield, but "liked" is a relative term in this context.
This thread has gone on long enough. Thanks for your comments.
Kevin
Kevin
I am less than clear that it is such a rigorous test to find a correlation over 1900-2000, and then test this by looking at the correlation over 1950-2000.
Thermometers, and speed cameras, have a large signal to noise; a car will be moving at 60, then slow to zero, and the readout has to match that. For trees and temperature, we are talking about ~0.6C over a century. The biological effect which we are looking to measure must be small, and that must give even more difficulty when establishing a correlation with temperature.
I note that it is common for tree records to give a high correlation for the test temperature period (e.g. 1900-2000), and a lower correlation for the verification period (e.g. 1850-1900). This is a situation which is consistent with your description of a "spurious" relationship with temperature.
Finally, I fear that even the simplest aspect of this procedure is biased. Take for instance, the fact that temperatures have risen for the last century, and so we are wanting a change in temperature; so we discard the samples with little variance (complacent) and only analyse the samples with high variance. Just imagine if temperatures had been stable for the last century; no doubt, we would be discarding the samples with high variance (sensitive), and the complacent samples would be giving us a great correlation with the temperature record. This is nothing less than throwing away samples which give the "wrong" result.
"In any event it is only trees which actually do show a correlation with temperature which are of interest. Whether they are common or not isn't especially relevant."
I made the point clearly that we can expect from our knowledge of a thermometer/ speed camera, that given quality control, almost all of these devices will measure temperature or speed. So we know how the system works, and that explains why we can predict how these devices will respond.
With trees, it appears that we cannot predict which trees/ stand will respond in advance. It looks like only a (very) small proportion of trees show a correlation with temperature, and it would follow that the vast majority show no such correlation. It looks like we do not know how these devices respond, and the idea that temperature correlation in a small % of trees proves temperature sensitivity looks rather speculative to me.
toodle-pip !
per
Tim Curtin opines:
"the MBH batch which post-NAS is valid only back to 1600"
I see Tim has fallen for the misinterpretation of the press release tautology. The press release said "Less Confidence in Temperature Reconstructions Prior to 1600". Anyone who has spent 5 minutes studying MBH99 would know that it shows a sudden increase in confidence limits before 1600. Repeating this in the press release sucks ignorant people into believing that it is news and gives denialists like Tim Curtin the opportunity to make blatantly wrong exaggerations.
By the way Tim, how are you going with your high school chemistry? Have you got up to the section on molecular weight yet?
dear chris
you are correct that mbh99 artificially inflates the 95% confidence intervals pre-1600 by an inadequately documented procedure. Nonetheless, the NAS panel has no confidence that this is an adequate procedure. They specifically state that the uncertainties prior to 1600 cannot even be quantified.
That is a long way away from mbh 98/99, and it is a significant difference to what they say.
cheers
per
per,
I wasn't planning to respond further in this thread, but I really can't let this pass. You wrote:
When you were typing that did you give even a moment's thought to what the terms variance and correlation actually mean? I'm pretty sure you didn't. To get in touch with these concepts, try putting the following values of three variables into a spreadsheet. Calculate the variances of T, U and V and the correlations Corr(T, U) and Corr(T, V).
First, lets see what happens when the trend is upwards:
Does U have greater variance than V or vice versa? Which is more highly cocorrelated with T?
Now let's rearrange the observations so that the trend is downwards:
Is there any change in the situation as regards variance and correlation?
Let's try shuffling the observations so that they show no particular trend:
Try using other numbers and ask yourself, has per been posting utterly nonsensical comments?
Dear Kevin
on reflection you are correct. It is certainly possible to create a sample with rising trend and lesser variance than a sample with zero trend, and greater variance.
Nonetheless, when it comes to tree ring samples, I suspect that this isn't the case. I suspect that the complacent samples show very similar ring widths throughout the chronology, and very little variation. I suspect that the "sensitive" trees have by definition greater variation, and that some will trend up, and some trend down, as you would expect from any sample of random numbers. I suspect that the flat and declining tree ring series show poor correlation with temperature, and those that are rising show a good correlation with temperature.
But let us accept that you are correct, and it is possible that the complacent series could have a rising or falling trend. Would you like to explain to me why jp discards such series when they could have a perfect correlation with temperature ?
yours
per
per mendacicizes for the nth time:
It looks like only a (very) small proportion of trees show a correlation with temperature, and it would follow that the vast majority show no such correlation.
I'd be happy to sign you in, David, to a dendro listserv so you can argue this weak bullsh*t there. Let me know. I'll be on vacation next week.
Best,
D
I think you are missing the point.
The Bristlecone/California Basin proxies have very little correlation to temperature, and they (naturally) have very little correlation to any other temperature proxy.
Take the Bristlecones out and you can't get a hockey stick.
Simple as that really.
Dano
> per mendacicizes for the nth time:
translation: I am going to call you names, because I have nothing sensible to contribute.
> I'd be happy to sign you in, David, to a dendro listserv
> so you can argue this weak bullsh*t there.
Translation: I don't have a clue, but it is really important that I pretend I know what I am talking about. I have nothing sensible to contribute.
thanks for your contribution, D !
per
But let us accept that you are correct, and it is possible that the complacent series could have a rising or falling trend. Would you like to explain to me why jp discards such series when they could have a perfect correlation with temperature ?
per,
I can't speak for jp but I can invent a story about trees if you want one, based on my rambles around the local park. The trees in my story don't much care about temperature. Herbivores improve their prospects by eating competitor plants and dumping lots of dung which fertilises them. So their rings exhibit a gradual rising trend, with little variance. On jp's definition they are complacent. It's true that they might have a strong correlation with temperature although it certainly could not be perfect unless temperature moves at a slower pace than a drugged snail. But such a correlation would be spurious. If observations on these trees were appled to a period where temperatures were high, but the helpful herbivores were absent, they would give the wrong answers. The fact that jp's procedure excludes these observations is therefore a point in its favour.
However there is little point in our discussing botany since we have both acknowledged that we know nothing about it. From a statistical point of view I see nothing wrong with the approach jp describes.
Now I have a question for you. In your comment you used the words "I suspect" to introduce a number of claims. Can you point to any data which justify your suspicions?
>It's true that they might have a strong correlation with
>temperature although it certainly could not be perfect
>unless temperature moves at a slower pace than a drugged
>snail. But such a correlation would be spurious.
Hmmm. Apparently, it is quite okay to announce that some statistical correlations are "spurious", but some correlations are not. Given that we have god-like knowledge of the cause of an increased ring size (your premise), then clearly we can announce spurious correlations. In the real world, we do not have god-like knowledge of the causes of tree growth; and in fact jp excludes these tree sites where temperature is not likely to be limiting.
So what it comes down to is that jp discards samples from sites which he believes to be candidates for temperature sensitivity, on the grounds of complacency. you have not suggested any coherent reason why he should discard those samples. Indeed, as you point out, the discarding of perfectly good samples comes very close to scientific misconduct.
yours
per
Kevin
You are very patient man. Per is a troll. Per states "jp discards samples from sites which he believes to be candidates for temperature sensitivity, on the grounds of complacency". That is a lie, I did not write that. I wrote about the criteria that influence site selection, not cherry picking data from individual trees to fit some temperature trend, but Per knows this. He simply keeps this thread rolling until he gets the last word with his child in man body catch phrase: tootle pip.
>Tree rings sites are selected because they represent
>locations where there is a high sensitivity in the ring
>growth to climatic conditions.
so sites are selected because they are candidates for temperature sensitivity
>When you are in the field and you are sampling trees if
>you see the ring series are complacent, you save your
>money and time and you move on to another site.
And you discard samples which are complacent.
I think it obvious that I was summarising what you said, rather than quoting you. My quotes show that what I said was true.
jp discards samples from sites which he believes to be candidates for temperature sensitivity, on the grounds of complacency
What is more, I cannot see why jp starts throwing allegations of "lie" about. I have directly cited what he said, and my paraphrase is meant to fairly reflect just what he said. If there is ambiguity, I should be clear that I understand jp to be saying that he discards all the samples from a site which is complacent; and that my phrasing was consistent with this.
It is a great shame that jp cannot bring his greatly superior knowledge to a civilised discussion without throwing insults about.
yours
per
jp:
per has successfully spammed this comment thread.
But any time a Hockey Stick post is created on the Internets, the FUD astroturf bots come out to spam the comment thread, so there is really nothing new here.
Best,
D
Per
Respect is earned. Let me explain it in simpler words: when it is clear that the samples at a site are complacent you give up on that site and (now stay with me because this is the tricky part) you open the garbage bag and you discard the complacent samples that you have collected. Actually I've been known to simply leave them on the forest floor.
That was difficult wasn't it. Done any reading yet?
You are very patient man.
Thanks jp. A man shirking his work if the truth be told. Rest assured that I read your comments upthread carefully. No attentive reader will be taken in by per's proclivity for "paraphrasing" and "translating" comments. He does it to me too. I deal with a simple question about trends, variances and the pitfalls of correlation by means of an equally simple story:
In per's hands my story then becomes an indefensible approach to scientific methodology:
My premise, mark you. This despite my making it quite clear that I am not a botanist.
I wasn't really expecting an answer to my question:
No surprise on that score.
>when it is clear that the samples at a site are complacent you give up on that site and (now stay with me because this is the tricky part) you open the garbage bag and you discard the complacent samples that you have collected.
That is what I said.
>Respect is earned.
You have featured two posts with oodles of name-calling, when I have merely accurately paraphrased what you have said. Did you learn this high level of intellectual discourse when you did your PhD, or do you have to be a Professor to pull this off ?
yours,
per
>The trees in my story don't much care about temperature. Herbivores improve their prospects by eating competitor plants and dumping lots of dung which fertilises them. So their rings exhibit a gradual rising trend, with little variance.
Dear kevin
It may be that you don't understand what a "premise" is; it should be clear that your little story above has premised that there is a gradual rising trend because of herbivore dung and herbivores eating competitors. "So" logically connects with the sentence before and implies causation; therefore you have simply stipulated that this is the cause of the increasing ring width, whether it is biologically likely or not, an issue that I did not address as you are not a biologist.
>Given that we have god-like knowledge of the cause of an increased ring size (your premise), then clearly we can announce spurious correlations.
well, it turns out that your example, with your god-like knowledge of cause and effect, isn't tremendously helpful. In the real world, we simply have samples, correlations, and no hotline to god. You appear to be favouring the view that we can simply discard the samples that you don't like (extracting the climate signal), until you are left with samples that just tell you what you want.
>From a statistical point of view I see nothing wrong with the approach jp describes.
I am gobsmacked. Wouldn't you have to know that removing samples on the basis of variance does not introduce a subsequent bias ? Clearly, if samples with a low variance had a particular type of response (e.g. no increment in ring size), you would be introducing a substantial bias into your samples.
Almost everything about this smacks of discarding data that you don't like. I am deeply suspicious that if you had a flat temperature record, it is the complacent samples that would be retained because they showed a "correlation" to temperature.
toodle-pip !
per
Dano:
>per has successfully spammed this comment thread.
translation: I am going to call him names, because I have nothing sensible to contribute.
>But any time a Hockey Stick post is created on the Internets, the FUD astroturf bots come out to spam the comment thread, so there is really nothing new here.
translation: I am going to call him names, because I have nothing sensible to contribute.
are you not going away sometime soon ?
toodle-pip !
per
per admitted:
Oh dear. Not only is that not clearly true, that's clearly not true.
"The Bristlecone/California Basin proxies have very little correlation to temperature,"
Says who?
"Take the Bristlecones out and you can't get a hockey stick."
If you take the Bristlecones out after 1450 you get the same old hockeystick. What are you going to blame for the hockeystick there?
Robert:
>Not only is that not clearly true, that's clearly not true.
well, that is a clear assertion. Would you please like to explain ?
I have suggest that you have a population consisting of (A +B), high and low variance tree rings. If type A has characteristic >X, and type B has characteristic "The Bristlecone/California Basin proxies have very little correlation to temperature,"
>Says who?
The NAS panel, e.g. http://www.climateaudit.org/?p=727
>If you take the Bristlecones out after 1450 you get the same old hockeystick.
This statement appears to be an error, lifted from an erroneous statement during the NAS press conference. See:
http://www.climateaudit.org/?p=724
From the NAS report:
>For periods prior to the 16th century, the Mann et al. (1999) reconstruction that uses this particular principal component analysis technique is strongly dependent on data from the Great Basin region in the western United States.
toodle-pip !
per
Robert:
>Not only is that not clearly true, that's clearly not true.
well, that is a clear assertion. Would you please like to explain ?
I have suggest that you have a population consisting of (A +B), high and low variance tree rings. If type A has characteristic >X, and type B has characteristic less than X, then a population of type A, or type B trees, will surely have a different X characteristic than trees with a mixture of A and B type trees.
this seems simple. What am I missing ?
yours, per
"mbh99 artificially inflates the 95% confidence intervals pre-1600"
What is "artificially" referring to?
"the NAS panel .. specifically state that the uncertainties prior to 1600 cannot even be quantified."
The only thing I've found so far related to this is:
"The uncertainties associated with reconstructing hemispheric mean or global mean temperatures from these data increase substantially backward in time through this period and are not yet fully quantified."
I can't see the phrase "CANNOT even be quantified" specifically stated in this. Is this the sort of bias we can normally expect from you?
>"The uncertainties associated with reconstructing hemispheric mean or global mean temperatures from these data increase substantially backward in time through this period and are not yet fully quantified."
so if you ask what the uncertainty is, the answer is that it cannot be quantified; I made no statement that the uncertainties will not be quantified in future. Yes, this is a paraphrase, and I am quite happy with it. You will normally be able to tell the difference between paraphrasing, and quotes by the little "" signs :-)
>The press release said "Less Confidence in Temperature Reconstructions Prior to 1600". Anyone who has spent 5 minutes studying MBH99 would know that it shows a sudden increase in confidence limits before 1600. Repeating this in the press release sucks ignorant people into believing that it is news...
It is news; their conclusions are very different to MBH 98/99, and the statistical criticisms of MBH are damning.
cheers
per
per asked:
per, rather than make pronouncements about what "clearly" introduces bias, why don't you try an actual numerical example. Suppose you have two trees, x1 and x2. Let x1 be very sensitive to temperature and x2 not at all--in fact, make it exacly like your example with constant growth so that it is completely unrelated to temperature. Predict the temperature based on tree x1, then on both x1 and x2. Whether you include x2 or not, the coefficient on x1 will remain the same. In fact (and this is what you might have learned in a statistics class), x2 needn't be constant; as long as it is uncorrelated with temperature, it won't introduce bias.
""The Bristlecone/California Basin proxies have very little correlation to temperature," Says who?
The NAS panel, e.g. http://www.climateaudit.org/?p=727"
Where do they actually say it?
"and they (naturally) have very little correlation to any other temperature proxy."
What do you mean "other proxy"? A proxy's primary purpose is to correlate with climate variables, not directly with another proxy.
""If you take the Bristlecones out after 1450 you get the same old hockeystick."
This statement appears to be an error, lifted from an erroneous statement during the NAS press conference."
Didn't come from anything to do with NAS. An MBH-reconstruction using the proxies from 1450, and without using the Bristlecones, was done by Wahl and Ammann 2006. Read it, you might learn something.
Dear robert
that is clear, if it isn't the question I asked. One of the issues which may have been implicit is that you need the whole stand of trees to have a correlation with temperature, and not just any one.
If the whole stand of trees has a correlation, that allows you to core old, dead tree stumps, and assume that they have the same good correlation with temperature. The biological "underpinning" is that the conditions are such that the temperature is limiting growth.
So there is a requirement (as jp stated) that the trees in a stand show a similar profile. 99 complacents and 1 "responder" doesn't cut it. I would understand that this must change your position ?
cheers
per
>Didn't come from anything to do with NAS. An MBH-reconstruction using the proxies from 1450, and without using the Bristlecones, was done by Wahl and Ammann 2006.
Are you referring to figure 4a or 5c, where exclusion of the bristlecones causes the reconstruction to fail ? Where the 1400s are up to 0.3 c warmer ?
>Read it, you might learn something.
quite !
per
"so if you ask what the uncertainty is"
They weren't talking about the uncertainty. The were talking about the uncertainties.
"and I am quite happy with it"
You think I care what you're happy with?
"You will normally be able to tell the difference between paraphrasing, and quotes by the little "" signs"
It has become pretty obvious that your "paraphrases" need to be taken with a grain of salt.
""The press release said "Less Confidence in Temperature Reconstructions Prior to 1600". Anyone who has spent 5 minutes studying MBH99 would know that it shows a sudden increase in confidence limits before 1600. Repeating this in the press release sucks ignorant people into believing that it is news...""
"It is news; their conclusions are very different to MBH 98/99, and the statistical criticisms of MBH are damning."
Yeah if you say so.
per surmised:
Nope. Your understanding is faulty. Adding or leaving out RHS variables that are uncorrelated to the dependent variable affects goodness-of-fit but not bias. It doesn't matter how many of them there are. In fact, leaving out (or adding) RHS variables that are collinear doesn't affect bias either. (It does affect the precision of individual coefficients).
per, this is very elementary stuff. Frankly, it makes me wonder about any other attestations you may have made of a statistical nature. As it happens, tomorrow I leave for vacation and I have much to do before that so I may not be able to respond again. I don't usually announce my comings and goings but in this case I wanted to be sure that you do not misinterpret my silence for agreement.
Sez per: You appear to be favouring the view that we can simply discard the samples that you don't like (extracting the climate signal), until you are left with samples that just tell you what you want.
Really, per? That's the way it appears to you is it? Let me tell you how it appears to me.
It appears to me that you asked me a to justify jp's exclusion of "complacent" sites from consideration, even though their growth might "have a perfect correlation with temperature". (The emphasis is mine, the bizarre words in quotes are yours).
It appears to me that I answered your question as follows:
It appears to me that you are doing that thing you call "paraphrasing" again. It is more usually referred to as misrepresentation. Sometimes it is called setting up a straw man.
>you asked me a to justify jp's exclusion of "complacent" sites from consideration, even though their growth might "have a perfect correlation with temperature".
good; we have something in common. What you did was invent a story about trees, which has god-like knowledge of why tree growth happens in a particular way as a postulate. This does not explain why complacent sites are discarded.
In short, you did not answer my question.
cheers
per
>Adding or leaving out RHS variables that are uncorrelated to the dependent variable affects goodness-of-fit but not bias. It doesn't matter how many of them there are.
hmm. I did check, but no-one has mentioned any "RHS variables", so presumably there will be a caustic retort coming along the lines of "you must be so stupid if you don't know what one of those is..."
I made clear I am neither a statistician or a botanist. I did set out my logic clearly, so a bit of gobbldegook that I cannot interpret doesn't really help much.
>Nope. Your understanding is faulty. per, this is very elementary stuff.
Yes, the obligatory sneer. Strangely, jp disagrees with you.
>At a good site for dendroclimatology there will individual trees with a high sensitivity, a strong correlation between the trees growth patterns within a stand and a chronology that has a significant correlation with a climate variable(s).
so jp requires that there is a strong correlation between tree growth patterns within a stand. jp discards data for stands where most of the trees are complacent.
I actually set out the biological basis for that reasoning, but you have not addressed that logic. Enjoy your holiday.
toodle-pip !
per
robert, let me rely on your post of June 30, 2006 03:13 PM .
For tree X1, let us have a correlation coefficient A1. For tree X2, let us have a coefficient A2. This is completely irrelevant to how you actually do the analysis in dendrochronology !
For working out the responsiveness of the stand of trees, what you do is average the responsiveness of all the trees in the stand. So you are averaging the growth response of the X1 tree, with the growth response of the X2 tree, in a given year. Once you have an average of the response for all the trees, that is when you do your correlation with temperature. So it appears that, contrary to your comments, it really could create a bias if you exclude low variance samples.
http://www.plantbio.ohiou.edu/dendro/analysis_methods.htm
>Not only is that not clearly true, that's clearly not true.
I guess it would be too much to ask for a civil response ?
toodle-pip !
per
""The Bristlecone/California Basin proxies have very little correlation to temperature," Says who?""
Well almost everyone really:
"A further aspect of this critique is that the single-bladed hockey stick shape in proxy PC summaries for North America is carried disproportionately by a relatively small subset (15) of proxy records derived from bristlecone/foxtail pines in the western United States, which the authors mention as being subject to question in the literature as local/regional temperature proxies after approximately 1850 (cf. MM05a/b; Hughes and Funkhauser, 2003; MBH99; Graybill and Idso, 1993). (p.9)"
From NAS Report Chapter 4
"The possibility that increasing tree ring widths in modern times might be driven by increasing atmospheric carbon dioxide (CO2) concentrations, rather than increasing temperatures, was first proposed by LaMarche et al. (1984) for bristlecone pines (Pinus longaeva) in the White Mountains of California. In old age, these trees can assume a "stripbark" form, characterized by a band of trunk that remains alive and continues to grow after the rest of the stem has died. Such trees are sensitive to higher atmospheric CO2 concentrations (Graybill and Idso 1993), possibly because of greater water-use efficiency (Knapp et al. 2001, Bunn et al. 2003) or different carbon partitioning among tree parts (Tang et al. 1999)....'strip-bark' samples should be avoided for temperature reconstructions, attention should also be paid to the confounding effects of anthropogenic nitrogen deposition (Vitousek et al. 1997), since the nutrient conditions of the soil determine wood growth response to increased atmospheric CO2 (Kostiainen et al. 2004).
If all the proxies are well correlated to temperature, then they should have some correlation to each other.
The Bristlecone/California Basin proxies do not correlate with the other proxies after about 1850, for reasons set out above.
That is why inclusion of the Bristlecone/California proxies is erronious.
Don't just take my word for it, graph Manns data on a spreadsheet, and you will see that the Bristlecones are way out of line with almost all the other proxies, and the other proxies do not, in general show a rising temperature trend in the 20th century.
AFTER about 1850.
Nothing said there suggests they're not a good proxy prior to 1850.
>Nothing said there suggests they're not a good proxy prior to 1850.
If they are not a good proxy after 1850 (when we have data), why should they be a good proxy before 1850 (when we can't tell) ?
querulously, per
Don
The controversy is about alleged anthropagenic climate change in the 20th century.
Please don't move the goalposts.
Whoops spelling should be "anthropogenic"
per wrote:
and
Poodle Tip,
I make my living either by answering clients' questions or teaching students to figure out how to answer their own. Last I looked, I hadn't seen a check in the mail from you so unless you're one of my students (a thought that should frighten both of us) you're eating into my vacation time and the hints and instruction I give you are solely for entertainment purposes. I can tell from your post that you didn't do what I suggested, which was to work out a numerical example. In class I tell my students that the homework is an integral part of their learning process and that I do not assign make-work problem sets. That web page you found was an excellent place to start but don't just dig it up and think that you understand cuz you looked at the pretty pictures. Work out the example. Then add 5 or 6 complacent oaks with constant ring size, e.g., 2.5mm for each year. You started off claiming that "clearly" leaving out small variance complacent trees "substantially" biases the results: well, trees with constant ring size have variance = 0, so that should qualify. Work out the example a second time. Now here's an exam question: "How did adding (or leaving out) those oaks with zero variance tree rings affect the predictive value? Show your work."
My classes generally have prerequisites. If a student comes into lecture and asks a question I'll answer it. If that student says he didn't meet the stat prerequisite, didn't do the homework assignment, and complains that I'd answered at a level beyond his understanding, I'd say that was rude. If he then makes an incorrect claim based on things he should have known, I'd say he's a buffoon. Don't be a buffoon.
Now I'm off to see what's left of the Tour, and I gotta hurry cuz if they eject any more riders they may have to cancel the whole damn thing.
This does not explain why complacent sites are discarded.
per,
From the outset my objective has been to explain why your criticism of jp's approach is without merit. So when you claim, without any evidence, that his methods exclude potentially useful data, I give you an example to show why data that looks useful to you may look worthless to him. Complacent sites show little variance, even in periods when temperature varies quite a lot. This does not mean that a series derived from a complacent site must be trendless. A variable can have a pronounced trend over a century and yet show little variance over periods of, say, five years. Is this the case with many complacent site, or few, or none at all? I have no idea. That's why I cannot tell you "why complacent sites are discarded", in the real world. All I have said is that there is a scenario in which complacent sites ought not to be included in datasets used for dendroclimatology. Whether the data actually support exclusion of complacent sites for that particular reason I don't know.
But limited as my contribution is, it is sufficient to show that your criticism of jp is unconvincing, to say the least. You said initially that complacent sites cannot show a rising temperature trend. I've explaned why that's not true: a series can have comparitively low variance (hence be complacent by jp's definition) and still show a rising or falling trend.
To spell it out further, since I fear you still haven't got it: suppose a variable X rises at a constant annual rate, while another variable, Y, follows a cyclical pattern but with an underlying upward trend. Over very long periods of time, X may track Y pretty closely. Does that make X a good proxy for Y? Not if you want to know what is happening in the cycles. Temperature in the 20th century shows an upward trend, but it doesn't show a steady upward trend. A good proxy variable picks up at least some of the short-term variation as well as the trend. A complacent series is by definition incapable of doing that.
>>I guess it would be too much to ask for a civil response ?
>>presumably there will be a caustic retort coming along the lines of "you must be so stupid if you don't know what one of those is..."
> I'd say that was rude. If he then makes an incorrect claim based on things he should have known, I'd say he's a buffoon. Don't be a buffoon.
so much bluster, when all you have to say is, "I got it wrong". The correlation is against averaged ring growth; the correlation is not worked out against individual trees.
do you have to give refunds when your tuition is defective ?
toodle-pip !
per
>From a statistical point of view I see nothing wrong with the approach jp describes.
>That's why I cannot tell you "why complacent sites are discarded", in the real world. All I have said is that there is a scenario in which complacent sites ought not to be included in datasets used for dendroclimatology.
let me get this right; you have given a positive and unambiguous declaration that discarding complacent site data is okay, yet you cannot justify why complacent sites are discarded and you accept the possibility that this could introduce bias.
>You said initially that complacent sites cannot show a rising temperature trend.
i think this unlikely, but accept that this is true. They could show a gradual increment.
>A good proxy variable picks up at least some of the short-term variation as well as the trend. A complacent series is by definition incapable of doing that.
You are having your cake and eating it. Complacent sites can show a trend, but they cannot show enough of a trend to correlate with temperature. Clearly, if the temperature didn't change much year to year, they can. This statement of yours is simply a baseless assertion.
You have also failed to establish why a statistical correlation derived from a complacent tree, should be any less meaningful than the same number derived from the analysis of a sensitive tree. Even in your tenuous example featuring "cycles", it would be quite acceptable for trees to give the long-term temperature trend. In short, I am saying that your requirement that a proxy picks up short-term temperature information is demonstrably wrong; tree rings cannot resolve on timescales shorter than a year for a kick-off.
cheers
per
Dear Kevin
>From the outset my objective has been to explain why your criticism of jp's approach is without merit. So when you claim, without any evidence, that his methods exclude potentially useful data,
it is not just jp's approach. Jacoby is a famous dendrochronologist, and he wrote this:
>The criteria are good common low and high-frequency variation, absence of evidence of disturbance (either observed at the site or in the data), and correspondence or correlation with local or regional temperature. If a chronology does not satisfy these criteria, we do not use it. The quality can be evaluated at various steps in the development process. As we are mission oriented, we do not waste time on further analyses if it is apparent that the resulting chronology would be of inferior quality. If we get a good climatic story from a chronology, we write a paper using it. That is our funded mission. It does not make sense to expend efforts on marginal or poor data and it is a waste of funding agency and taxpayer dollars. The rejected data are set aside and not archived. As we progress through the years from one computer medium to another, the unused data may be neglected. Some [researchers] feel that if you gather enough data and n approaches infinity, all noise will cancel out and a true signal will come through. That is not true. I maintain that one should not add data without signal. It only increases error bars and obscures signal. As an ex- marine I refer to the concept of a few good men. A lesser amount of good data is better without a copious amount of poor data stirred in.
If he doesn't like the data (gets the wrong correlation), he bins it.
cheers
per
More from per: let me get this right; you have given a positive and unambiguous declaration that discarding complacent site data is okay, yet you cannot justify why complacent sites are discarded and you accept the possibility that this could introduce bias.
That's your best effort at getting it right?
Let's start with this guff about a "positive and unambiguous declaration".
I wrote that "from a statistical point of view I see nothing wrong with the approach jp describes." Of course I cannot comment on whether jp's approach is sound from, say, a botanist's perspective, although I have no reason to doubt it. There may also be something wrong from a statistical perspective. If so Robert is more likely to spot it than I am. But for now my endorsement stands, for what it's worth.
In the mind of per this is transformed into "a positive and unambiguous declaration that discarding complacent site data is okay", which tells us something about per's capacity for misreading. There is a distinction between saying that per's efforts to demonstrate an error have failed miserably, and saying unequivocally that no error of any kind exists. Most readers can grasp that distinction.
For all I know maybe jp is doing something wrong. But several days after grandly announcing "I will even take you on at dendrochronology", the challenger hasn't even laid a glove on him.
Since when is it up to me to "justify why complacent sites are discarded", per? You are the one claiming that there is something wrong with jp's procedure. It is up to you to show why they should not be discarded. This you have failed to do.
Next per says I accept the possibility that this could introduce bias. Do I, per? Your exchanges with Robert suggest that you don't even know what the term bias means in the context of statistics. As for me, Crtl-F confirms that the only time I used the word "bias" in this thread was when I took per to task for using it in an unintelligible way:
per's response to that suggested that he was dropping the claim of bias:
That, folks, shows just how much nonsense per can cram into a few lines of text. It comes after an indent in which he puts together two remarks of mine which don't even come from a single comment. What the idea of that was is anyone's guess. I will leave the rest for now. The weather is fine and anyway the World Cup is becoming interesting.
Mr Bell
We have now come full circle. Early in this thread I pointed out that research is undertaken for a purpose. I also pointed out that tree growth is influenced by many variables. At some sites it may not be possible to develop a chronology that is useful for climatic reconstruction. That may be evident in the field, it may be evident in the lab. What Jacoby points out is that there is no useful purpose in pursuing a site or chronology when it has little value for climatic reconstruction, if the purpose of the work is climatic recontruction. Only a troll would interpret this to mean "If he doesn't like the data (gets the wrong correlation), he bins it."
Jacoby states "If we get a good climatic story from a chronology, we write a paper using it". Now listen closely because this is the tricky part for conspiracy theorists: it does not matter if that story supports or refutes the 'consensensus' view. What matters is that the chronology is of high quality and the story gets published.
Here is an opportunity for the clowns of the audit, go do your own work and publish it.
per digs deeper with:
Puddle Mop:
*Of course* the correlation is against averaged ring growth. That you didn't know that means that you didn't even try to work the example. Do the example.
Muffin Top:
I give "F"s when students don't do their homework. Please let your next post be the results of your worked example.
It's not "moving the goalposts" to point out that your cite doesn't support your conclusion.
Unless asking that you tell the truth is moving the goalposts. Would that be it?
One more time.
The Bristlecones are useless as a temperature proxy after 1850.
The "Hockey Stick" graph depends on the Bristlecones for it's upward trend in the 20th century, therefore the "Hockey Stick" graph is useless.
The upward trend shown by the "Hockey Stick" is the basis for the allegation that man made CO2 caused/causes any temperature increase but is based on useless data, and a useless graph.
Show me any non Bristlecone tree based temperature proxy which indicates a temperature increase in the 20th Century.
>I wrote that "from a statistical point of view I see nothing wrong with the approach jp describes." ... There may also be something wrong from a statistical perspective... But for now my endorsement stands, for what it's worth.
If your statement is that you see nothing wrong with X, but you now qualify this by saying that there may be something wrong with X, I am quite happy to withdraw any suggestion that a statement that you made has any positive or unambiguous meaning whatsoever!
>Next per says I accept the possibility that this could introduce bias.
> suppose a variable X rises at a constant annual rate, while another variable, Y, follows a cyclical pattern but with an underlying upward trend. Over very long periods of time, X may track Y pretty closely.
That is your quote, and you are premising that for complacent trees, the growth (X) tracks temperature (Y) over a very long period "pretty closely". Systematically discarding sites with such a pretty close relationship of temperature and growth will bias your estimates of how well trees measure temperature, unless sensitive trees show exactly the same response.
>I think I now have a fair idea of what per's concern is. At all events I will give it one last shot, since it relates to statistics not botany (of which I know nowt). Suppose we have a large table of numbers, consisting of hundreds or maybe thousands of columns. The first column represents temperature and contains 100 numbers corresponding to the years 1901-2000. Each of the other columns represents a tree and contains 200 numbers which may or may not track temperature closely for the period 1801-2000. The optimists assert that some unknown proportion of the columns are a good proxy for temperature, but the only way to identify them is by statistical methods. The table is all we have.
Err, this is the crux, and what you still haven't addressed. In fact, your table contains the "cherry-picked" data of sites with "good" correlations, and all the sites with "bad" correlations are simply buried, and never archived. You have simply selected those sites which have a good correlation, and are now using the fact that these sites have a correlation with temperature to prove that they are sensitive to temperature.
In fact, this is indistinguishable from the cardinal error of throwing away data you don't like till you get the "right" answer. This analysis says nothing about whether these sites are sensitive to temperature, because you have pre-selected on correlation to temperature.
>If for example a researcher is testing the hypothesis that a particular species of tree is sensitive to temperature, or that its sensitivity depends on a particular set of variables, then of course it would be inexcusable to make lots of observations and throw out the ones that don't fit. That's not the case being discussed here. I refer you to jp's explanation:
>>If the objective of the research is to extract a climate signal from a tree ring series it would be of no value to sample trees that were not sensitive to climate.
So what jp describes is a procedure which is indistinguishable from "make lots of observations and throw out the ones that don't fit [correlate]", but if we call it "extract[ing] the climate signal", then that's okay.
Toodle-pip !
per
>Muffin Top:I give "F"s when students don't do their homework. Please let your next post be the results of your worked example.
what a surprise, abuse ! One of the minor things that people forget is that there is such a thing as noise, or biological variation. So if you do an average of (signal + zero), then the resulting arithmetic mean will retain the same correlation, no matter how much you dilute the signal. This is not true in biological systems, where the signal is frequently not much greater than the noise. You ony have to dilute signal into a little bit of noise, and lo ! the signal becomes indistinguishable from noise.
looking forward to getting my homework marked ! Can I bill you for the tuition I am giving you ?
toodle-pip !
per
""Didn't come from anything to do with NAS. An MBH-reconstruction using the proxies from 1450, and without using the Bristlecones, was done by Wahl and Ammann 2006."
Are you referring to figure 4a or 5c,"
Glad you finally realized it wasn't "lifted from an erroneous statement during the NAS press conference". Scenario 6.
"where exclusion of the bristlecones causes the reconstruction to fail ?"
I'm talking about "reconstruction using the proxies from 1450, and without using the Bristlecones" where the reconstruction passes.
"Where the 1400s are up to 0.3 c warmer ?"
It's beside the point here but there's not much point talking about attempted reconstructions that fail validation such as using the 1400 network with Bristlecones removed. The attempt fails. End of story.
>What Jacoby points out is that there is no useful purpose in pursuing a site or chronology when it has little value for climatic reconstruction, if the purpose of the work is climatic recontruction.
Dear jp
I am quite happy to be educated, and will accept if you can explain why I am wrong.
But what I hear you (and Jacoby) to say is that you select sites on the basis of their correlation with temperature; data from other sites are binned. The case is then made that because there is a correlation with temparture, these trees are sensitive to temperature.
Kevin Donoghue says:
>it would be inexcusable to make lots of observations and throw out the ones that don't fit
You have made a deus ex cathedra pronouncement that there is a climate signal there which can be extracted. But I cannot see the reason why what you are doing is different from Kevin's description.
>Only a troll would interpret this to mean "If he doesn't like the data (gets the wrong correlation), he bins it."
Reading Jacoby's statement, it is quite clear that he says he bins data that doesn't have "correspondence or correlation with local or regional temperature". I have the utmost concern that you pre-select data on the basis of temperature correlation, and then claim that tells you temperature senstivity. You could do exactly the same thing for any series of random data, and it would tell you exactly the same thing.
toodle-pip !
per
>""If you take the Bristlecones out after 1450 you get the same old hockeystick."
>An MBH-reconstruction using the proxies from 1450, and without using the Bristlecones, was done by Wahl and Ammann 2006.
>>It's beside the point here but there's not much point talking about attempted reconstructions that fail validation such as using the 1400 network with Bristlecones removed. The attempt fails. End of story.
Let me see if I understand you, Chris. You have said that if you take the Bristlecones out, you get the same old hockeystick, and you cited W&A. You now point out that this reconstruction fails in the absence of bristlecones !
Just joining the dots, don't you realise that you have undercut your original statement ?
cheers
per
"Show me any non Bristlecone tree based temperature proxy which indicates a temperature increase in the 20th Century"
http://www.cgd.ucar.edu/ccr/ammann/millennium/refs/WahlAmmann_ClimaticC… Scenario 6 1450 proxy network.
"The Bristlecone/California Basin proxies do not correlate with the other proxies after about 1850"
So? They're only needed for reconstructions before 1450. Last time I checked 1450 was waaaay before 1850.
>"The Bristlecone/California Basin proxies do not correlate with the other proxies after about 1850"
So? They're only needed for reconstructions before 1450. Last time I checked 1450 was waaaay before 1850.
Ouch ! the point is that in the region of time where we can check if they are temperature measures (1850+), we can demonstrate that they are not. If they are not thermometers when we can test them, why should they act as thermometers in the 1400s, when we cannot test their properties ?
toodle-pip !
per
"If they are not a good proxy after 1850 (when we have data), why should they be a good proxy before 1850 (when we can't tell) ?"
Er, there's more than one way to skin a cat. Just because there weren't many thermometers around before 1850 doesn't mean we can't find some other way to calibrate a particular proxy before 1850.
Turtle pop,
Why do you avoid working out the example you yourself found? The airport shuttle arrives soon so time's a-wasting.
>Why do you avoid working out the example you yourself found?
>If he then makes an incorrect claim based on things he should have known, I'd say he's a buffoon. Don't be a buffoon.
Time for your homework, my post of July 1, 2006 12:34 PM
toodle-pip !
per
"Let me see if I understand you, Chris."
This'll be interesting.
"You have said that if you take the Bristlecones out,"
after 1450. At least put a few dots where that went.
"you get the same old hockeystick,"
from 1450
"and you cited W&A. You now point out that this reconstruction fails in the absence of bristlecones !"
I wasn't talking about the same reconstruction, which you would have realized if you had ever read and understood W&A. The reconstruction using the 1450 proxy network is different from the reconstruction using the 1400 proxy network because the 1400 proxy network has a lot fewer proxies.
You'd be a lot better off spending more time reading the work of people who's jobs is this stuff and less time writing your opinions on blogs.
RE:"Show me any non Bristlecone tree based temperature proxy which indicates a temperature increase in the 20th Century"
http://www.cgd.ucar.edu/ccr/ammann/millennium/refs/WahlAmmannClimaticCh… Scenario 6 1450 proxy network.
"Results for the exclusion of the bristlecone/foxtail pine series developed according to
scenario 3 are shown by the green curve in Figure 2. The exclusion of these proxy records
generally results in slightly higher reconstructed temperatures than those derived from inclusion
of all the proxy data series, with the greatest differences (averaging ~ +0.10°) over the period
1425-1510. The highest values before the 20th century in this scenario occur in the early 15th
century, peaking at 0.17° in relation to the 1902-1980 mean, which are nevertheless far below the
+0.40-0.80° values reported for scenario 1. The verification RE scores for this scenario (Table
2) are only slightly above the zero value that indicates the threshold of skill in the independent
Feb 24, 06 Wahl and Ammann Climatic Change, in press
29
verification period, and the verification mean reconstructions are correspondingly poor. These
results, which cannot be attributed to calibration overfitting because the number of proxy
regressors is reduced rather than augmented, suggest that bristlecone/foxtail pine records do
possess meaningful climate information at the level of the dominant eigenvector patterns of the
global instrumental surface temperature grid. This phenomenon is an interesting result in itself,
which is not fully addressed by examination of the local/regional relationship between the proxy
ring widths and surface temperatures (noted in section 1.1) and which suggests that the "all
proxy" scenarios reported in Figure 2 yield a more meaningful comparison to the original MBH
results than when the bristlecone/foxtail pine records are excluded."
If you exclude the Bristlecones the "skill" of the result is minimal.
If you include the Bristlecones (which have no correlation to local temperature after 1850) the "skill" increases, but only because the proxy data "skill" is in this case being compared to "non-local" temperature by means of a "teleconnection".
So there you have it. No "skill" in relation to local temperatures with either method.
The only way they can find "skill", is by connecting them to temperatures that may have occurred elsewhere in the world, but not in the California Basin.
per wrote:
Noodle lip:
Brrrrrrinnng! Just in time. Is that your final answer? Okay.
Let Y be a vector of temperatures. Let X be a vector which is a r.v. of the (average detrended) deviation of sensitive tree rings, just as was shown in the example you dug up. Let Z be the (average) deviation for a bunch of complacent tree rings with zero variance. Zero variance means they're a constant. Adding a constant to X doesn't change its correlation with Y. Adding a constant to X doesn't change its variance, either. So adding a constant to X doesn't change the coefficient for X in its regression with Y. So there is no bias. QED.
So, how'd you do? Hmmm. You claimed that leaving out (or adding) the complacent trees would bias the results. Ooooh, not a good answer.
It's been fun. Keep in touch.
"Just because there weren't many thermometers around before 1850"
I should point out that there probably were a reasonable number of thermometers in North America for a fair while before 1850. So you could probably calibrate Bristlecone proxies before 1850 without using intermediate proxies. But as I said, there's more than one way to skin a cat.
RE:"Show me any non Bristlecone tree based temperature proxy which indicates a temperature increase in the 20th Century"
http://www.cgd.ucar.edu/ccr/ammann/millennium/refs/WahlAmmannClimaticCh… Scenario 6 1450 proxy network.
"Results for the exclusion of the bristlecone/foxtail pine series developed according to scenario 3 are shown by the green curve in Figure 2."
Since when do the words "Scenario 6" have the same meaning as the words "scenario 3"?
>a vector of temperatures
okay, what is a vector of temperatures ?
>Let X be a vector which is a r.v. ...
okay, you have been careful to avoid specifying what an r.v. is, and I don't know. Is that like an "r.h.s.", or is it more like a WTF ?
I have been careful to set out what I am saying in simple and plain english. Switching to undefined acronyms, using obscure jargon; do you think that gives you an appearance of knowledge ?
>Let Z be the (average) deviation for a bunch of complacent tree rings with zero variance.
Okay, this one I get. When I said that biological samples have noise, you have replied with "let there be no noise in biological samples". That is kind of like sticking your fingers in your ears, shutting your eyes, and shouting "I can't hear you".
It seems that you don't know that biological samples have noise. It seems that you cannot even parse my simple sentences that state that biological samples have noise. Maybe you don't know what noise is ?
>So there is no bias. QED.
doesn't hold for non-zero variance. Go back to beginning. start again.
>Ooooh, not a good answer.
fess up, boy, that for biological samples (my contention) you are wrong ! It's good for the soul :-)
yours
per
>Just because there weren't many thermometers around before 1850
>I should point out that there probably were a reasonable number of thermometers in North America for a fair while before 1850.
these were both your quotes; are you now arguing with yourself ?
Anyway, I am sure you can skin a cat, but the fact is the bristlecone pines don't show a correlation with local temperature post 1850; how on earth can you make a case that they are temperature proxies ?
cheers
per
OK, David Bell, that's enough trolling. "Vector" and "r.v." are not obscure jargon.
You're banned for 24 hours.
"Since when do the words "Scenario 6" have the same meaning as the words "scenario 3"?"
They don't, but I think you'll find the trees are the same.
""Since when do the words "Scenario 6" have the same meaning as the words "scenario 3"?"
They don't, but I think you'll find the trees are the same."
The trees might be the same but Scenario 6 is the answer to your question and scenario 3 isn't. If you had bothered reading Scenario 6 you would have known that.
"Anyway, I am sure you can skin a cat,"
And I'm sure you understand what a metaphor is too.
"but the fact is the bristlecone pines don't show a correlation with local temperature post 1850; how on earth can you make a case that they are temperature proxies ?"
Have you started spending more time reading the work of people who's jobs is this stuff and less time writing your opinions on blogs yet? Getting banned should be an excellent opportunity for you to do so. Anyway, regarding calibrating proxies without using contemporary thermometers, this can be done by calibration from other proxies that have been calibrated against thermometers. There are 250 years of high quality temperature reconstructions from 1600 to 1850 that enable this to be done.
""Let Z be the (average) deviation for a bunch of complacent tree rings with zero variance."
Okay, this one I get. When I said that biological samples have noise, you have replied with "let there be no noise in biological samples"."
One thing Einstein said was "imagination is greater than knowledge". So no imagination, no knowledge.
"That is kind of like sticking your fingers in your ears, shutting your eyes, and shouting "I can't hear you".
Does anyone else notice the hypocrisy going on here?
>Anyway, regarding calibrating proxies without using contemporary thermometers, this can be done by calibration from other proxies that have been calibrated against thermometers.
Maybe you missed it when several of us wrote that the bristlecones do not show a correlation versus local temperature post-1850; in other words, they fail ! How can you suggest that calibration against a different proxy validates them, when you know that they fail against local thermometer readings ?
Graybill and Idso, when they characterised many of the californian great basin bristlecones, explicitly set out that they are not temperature proxies ! You are arguing against the people whose job it was to characterise these trees.
> Getting banned should be an excellent opportunity for you to do so.
you may imagine that getting "banned" is like a legal sanction, or some sort of slut on my reputation. I think it reflects a bit more on TimL than me.
cheers
per
I think everyone is free to check that Tim got you dead to rights per and dealt with (what you may now believe to have been) your little booboo very reasonably. Making some fair, modest yet winning points would be your best comeback but I'm betting you'll stick with playing the girlish smartarse. Please prove me wrong.
jp said above:
Here is an opportunity for the clowns of the audit, go do your own work and publish it.
When I say this at the clown site, I get shouted down.
There is nothing in a position when the holders of that position won't go out and prove it.
Best,
D
>I think everyone is free to check that Tim got you dead to rights per
>that's enough trolling.
QED; what more needs to be said ?
If you are referring to the bit about vector, and r.v., I still don't know what an r.v. is, and I don't see how I can guess.
I confess i am not a statistician, and I asked politely for the meaning of the word "vector", as it didn't fit in with my knowledge of what a mathematical vector is. Although there is a meaning in computer science (http://en.wikipedia.org/wiki/Vector), I don't see how I can reasonably know this unless i am a computer scientist. Is this Tim's reason for banning me ?
>I'm betting you'll stick with playing the girlish smartarse
Is this an example of "some fair, modest yet winning points" ?
just wondering,
per
Klein's law, now per's law:
there's only so much hand-waving one can do before it clears away the smoke screen.
Best,
D
Dano:
>there's only so much hand-waving one can do...
how strange ! Dano has not engaged in the debate, nor made a substantive point. He has told us that there are listservs (somewhere), or stuff in a library (somewhere), and strangely enough, he talks a lot about hand-waving.
toodle-pip !
per
per,
In this context a vector, X, is a set of N observations (x1, x2, x3, ... ,xN) of a variable, and an r.v. is a random variable (not, as you may suppose, a recreational vehicle). RHS stands for right-hand side (of a regression equation).
I believe that when he banned you, Tim Lambert was acting on the following assumptions:
Your name is David Bell.
per is short for peroxisome, as in such memorable remarks as "glucocorticoid-induced PPAR alpha is linked to peroxisome proliferator mitogenesis".
You know at least as much about statistics as a typical science undergraduate and probably a damn sight more.
You feign ignorance in order to disrupt comment threads.
If these assumptions are correct, your banning was thoroughly justified. Indeed a good kick up the arse wouldn't be entirely undeserved.
If these assumptions are incorrect then TL owes you an apology.
Tim,
If you reckon I'm feeding a troll, please feel free to delete this comment.
Dear Kevin
thanks for clarifying rv, and rhs; I have not come across either abbreviation, or that use of vector, in context before.
I guess if you have done physical science at university, or even maths/ stats, these might be fairly elementary usage. However, I have never done maths/physical science/ computing at university, and such stats as I did do were at an elementary level.
>You feign ignorance...
I have said twice I hadn't come across that use of vector, and I have also said I didn't know what rv and rhs were in context. If you choose to assume that I am lying, based on no knowledge whatsoever, that is your call.
yours
per
Well, MarkR posted why above, though at the time he didn't realize that his quoted source didn't support his (or your) position ...
>Well, MarkR posted why above, ...
is this what you were talking about ?
>If you include the Bristlecones (which have no correlation to local temperature after 1850) the "skill" increases, but only because the proxy data "skill" is in this case being compared to "non-local" temperature by means of a "teleconnection".
Steve McIntyre at climate audit did some lovely stuff on this recently. Someone used a proxy series - on condition it had to show good correlation with local temperature. Sure enough it did; but it wasn't the local temperature. Once you start sampling all the local temperatures, using just the 9 closest temperature stations, you can get your correlation statistics up to pretty reasonable simply by choosing the best statistic out of 9...
toodle-pip !
per
Dano has not engaged in the debate, nor made a substantive point. He has told us that there are listservs (somewhere),
Wrong.
I've pointed out you are an annoying bobblehead, full of sh-t and this listserv you are so afraid of will further point out your mendacious, obfuscatory and - frankly - full of cr-p FUD.
That is: you don't have the courage to argue your weak position on a dendro listserv.
Best,
D
Re: "Steve McIntyre at climate audit did some lovely stuff on this recently."
Per, the people at climate audit have never done any "lovely stuff". They have never done anything constructive in climate research, and their blog is the favourite "climate science" blog of fools, industry PR hacks, and loony libertarians who have no real climate science background or serious record in climatology.
If you are to cite any climate science blog at all, please use RealClimate.org as your source and not one done up by economists, former mining executives, or "journalists".
Wikipedia has a good [description of Dr Bell's conduct](http://en.wikipedia.org/wiki/Internet_troll#Attention-seeking_trolls). I don't think it is plausible that someone with a PhD in biology would really believe that "vector" is obscure jargon.
Please do not feed the troll.
"the people at climate audit have never done any "lovely stuff". They have never done anything constructive in climate research."
showing that the bulk of climate proxy research uses grey data and undisclosed methods is very instructive.
Do you endorse hiding data and methods?
>I don't think it is plausible that someone with a PhD in biology would really believe that "vector" is obscure jargon.
I am just wondering if you know what is involved in a UK biology undergraduate degree. Do you realise you can do such a degree while doing no formal maths, physical science or computing courses ? Do you realise that there can be no formal courses during a UK PhD, and that math/physical science/ computing would not normally be the subject matter of a biology PhD ?
I can only wonder what the factual basis for your belief system is; but I can point out to you that not everyone has studied computer science.
toodle-pip !
per
>They have never done anything constructive in climate research,...
I count several publications in the peer-reviewed press, and they are also largely responsible for ensuring the NAS review happened. Strangely enough, the NAS review seems to accept many of the points made by M&M :-)
toodle-pip !
per
it is truly rare to come across such an incisive piece of prose, making such an elegant, but well-thought through contribution to the debate:
>I've pointed out you are an annoying bobblehead, full of sh-t and this listserv you are so afraid of will further point out your mendacious, obfuscatory and - frankly - full of cr-p FUD. That is: you don't have the courage ...
Best,
per
Assume per has not done any math or statistics, then what is he doing commenting on statistical analysis? If he has done statistics he should know what a vector is.
>If he has done statistics he should know what a vector is.
As it happens, I have six textbooks about statistics on my desk. According to the index, one book out of six has the word "vector" indexed, and this book is a "howto" guide for a particular statistical programme.
Don't let me spoil your misconceptions with any facts !
toodle-pip !
per
""Anyway, regarding calibrating proxies without using contemporary thermometers, this can be done by calibration from other proxies that have been calibrated against thermometers."
Maybe you missed it when several of us wrote that the bristlecones do not show a correlation versus local temperature post-1850;"
Did you say they showed no correlation with temperature before 1850?
"How can you suggest that calibration against a different proxy validates them, when you know that they fail against local thermometer readings ?"
As McIntyre likes to remind us, the Bristlecone proxies were interfered with by rising CO2 level since 1850. This interference didn't stop them from being proxies before 1850.
""Getting banned should be an excellent opportunity for you to do so."
you may imagine that getting "banned" is like a legal sanction, or some sort of slut on my reputation. I think it reflects a bit more on TimL than me."
I never expected you to say that.
In any case the suggestion that Bristlecone proxies cause a huge error to temperature reconstructions solely during the period where the reconstructions are dependent on the Bristlecone proxies (before 1450) relies on believing a set of incredible co-incidences. Somehow we're expected to believe that even though reconstructions using Bristlecone proxies agree extremely well with reconstructions not using Bristlecone proxies after 1450 that somehow the Bristlecone proxies suddenly go mad before 1450 when they haven't caused any problem after 1450. So they only go crazy just the moment we can't check up on them while every time we can check them, and they're not interfered with by something, they behave themselves. You can believe that if you want to but don't expect me to agree with you.
And don't forget we have a perfectly good hockeystick from 1450 to now without touching Bristlecones.
"showing that the bulk of climate proxy research uses grey data"
So coming up with a reconstruction that fails validation proves that your data is grey and not that you are incompetent.
Interesting.
Per, one can buy any number of textbooks. Reading them and understanding them is another thing. Given the ubiquetous (BRING BACK THE SPELL CHECHER TIM!) reach of linear algebra into all branches of mathematics including statistics one is tempted to ask which books you have.
>Did you say they showed no correlation with temperature before 1850?
Forgive me, but I don't recall you showing that. Under any circumstances, it is irrelevant. They do not show correlation with local temperature post-1850. There are several (speculative) hypotheses why that may be so, but no proof. It is sufficient to note that they do not correlate with temperature.
Given that is so in the area where we have made a test, how can we possibly suggest that they will be temperature proxies at any other time ?
Even if you were able to show that they showed a correlation with local temperature from say 1600-1850, how do we know that there will not be other occasions in history when they would fail to show a correlation with local temperature again ?
Science is about proving things; not just saying, " it might be so..."
toodle-pip !
per
chris,
talking about incompetence. One author doesn't want to share his original data, his graphs are therefore (wrongly !) digitised by author 2. Conclusions are drawn from the wrong data and nobody cares to archive.
science with a captital S.
not.
Re O'Neill
Why are you referring me to a 1450 proxy network, when I asked about the 20th Century?
PS Link to ucar doesn't work at mo.
Here's support for the positions taken (in part) by the NAS and by per and MarkR, in the Submission by David Holland to the UK's Stern Review:
"21. The Stern Review should note that many of the proxy reconstructions, like Dr. Mann's MBH98 which suggest the 20th century is exceptional in the last millennium, are based largely on the width of tree rings. Most of us know that trees grow better when it is warmer but we also know that they need water and sun light and of course CO2. Factors like age, disease and local competition also
affect growth. Thus the width of a tree ring may vary in a linear way in relation to average temperature over a range of temperatures, providing all the other factors
that affect it remain constant. In very few places and only for limited time spans can it be said that tree rings may respond linearly to average temperature....Non-linear processes such as plant growth do not lend themselves to analysis using linear algebra upon which statistical analysis relies.
22. Tree ring width data was collected for dendochronology long before climate change was an issue but few temperature reconstructions use those after the 1960's. The Stern Review should understand why. In 1998, Briffa et al presented a paper entitled "Trees tell of past climates: but are they speaking less clearly today?" In [their] graph it can be seen that after 1960 tree rings are poor proxies for temperature. This is euphemistically referred to as the "Divergence Problem." However, it does not prevent the same data being used in other papers to corroborate the "hockey stick". The inconvenient data after 1960 is simply omitted. In other fields leaving
out contrary indications as significant as this would be considered dishonest. This data is included in the "spaghetti" diagrams shown in [Stern's] Technical Annex and in the IPCC TAR 2001 as corroboration of Dr Mann's hockey stick.
23. Clearly substantial uncertainty exists over reconstructions of past global temperatures based on proxies and particularly tree rings. Tree ring series, or
parts thereof, are selected or cherry-picked for use in reconstructions. Series from the same area can exhibit differing trends and without seeing the selection
criteria, which are rarely available, it is reasonable to suggest that there is bias in their selection."
Hans,
"science with a captital S.
not".
With your publication record in science, you should know.
J
Jeff do you endorse hiding data and methods?
"Here's support for the positions taken (in part) by the NAS and by per and MarkR, in the Submission by David Holland to the UK's Stern Review"
So why do you think anyone would be interested in an out-of-date re-hash of the usual denialist misinformation? If you're going to feed us denialism Tim at least make it up to date. BTW, how are you going with your study on molecular weight?
""Did you say they showed no correlation with temperature before 1850?"
Forgive me, but I don't recall you showing that."
I never said I did.
"Under any circumstances, it is irrelevant."
Yeah if you say so Mr Dendroclimatologist.
"They do not show correlation with local temperature post-1850."
Yeah if you say so etc. Show me any up-to-date scientific publication that says they do not show ANY correlation with local temperature post-1850. And words such as "being subject to question" and "should be avoided" do not mean the same thing as "do not show ANY correlation".
"Science is about proving things; not just saying"
there is nothing when there is something.
"One author doesn't want to share his original data"
Yeah I believe you.
RE:"Show me any non Bristlecone tree based temperature proxy which indicates a temperature increase in the 20th Century"
http://www.cgd.ucar.edu/ccr/ammann/millennium/refs/WahlAmmannClimaticCh… Scenario 6 1450 proxy network.
"Why are you referring me to a 1450 proxy network, when I asked about the 20th Century?"
The 1450 proxy network lasts from 1450 to the 20th century (1980 or thereabouts).
"PS Link to ucar doesn't work at mo."
Works now.
>>"They do not show correlation with local temperature post-1850."
>Yeah if you say so etc. Show me any up-to-date scientific publication that says they do not show ANY correlation with local temperature post-1850.
Sadly, there are not whole publications devoted to showing single correlations, and i guess I should be clear. When I say "they do not show correlation", that is shorthand for "they do not show a statistically significant correlation"; of course there is a correlation of some sort.
however, you can get some of these correlations at:
http://www.climateaudit.org/?p=697#more-697
all the best !
per
Re: "however, you can get some of these correlations at: http://www.climateaudit.org/?p=697#more-697"
Even the CA guys are showing an alarming warming trend over the last three decades.
>Even the CA guys are showing an alarming warming trend over the last three decades.
is that contentious ?
cheers
per
Stephen Berg "Even the CA guys are showing an alarming warming trend over the last three decades."
The link you provide shows a graph of the reproduction of the Mann Hockeystick (which is discredited because it overweights the California Basin Bristlecones), and it also shows a graph of the actual Pacific Basin Bristlecone Proxy, and the statistical significance tests that Steve McIntyre did to check the Bristlecones validity as a local temperature proxy:
"....a first test, I calculated decadal averages in decades starting in year 6 and repeated the above calculation. Because there are only 9-10 degrees of freedom, one expects that some apparently high correlation might not be accompanied by statistical significance. In this case, I got a correlation of 0.38 (as compared to 0.56 cited in Jones and Mann 2004, quoted in Osborn and Briffa 2006). Looking back, they did their calculation on a 1901-1980 period, while I did it for the full period. I've not bothered trying to see what I get for 1901-1980 as I don't think that it matters anyway. The adjusted r-squared is only 0.056; the t-statistic is a mere 1.29 (not significant) and DW is a ghastly 0.36."
So you see, to put it in scientific terms, the Bristlecones are useless as a temperature proxy in the 20th century.
RE:"Show me any non Bristlecone tree based temperature proxy which indicates a temperature increase in the 20th Century"
I looked again, scenario 6 covers the period 1400-1499 not the 20th Century.
I ask you again. Show me a tree base proxy, that is reliable for local temperatures, ie Non Bristlecone, that also graphs as a Hockey stick.
RE:"Show me any non Bristlecone tree based temperature proxy which indicates a temperature increase in the 20th Century"
"I looked again, scenario 6 covers the period 1400-1499 not the 20th Century."
Figure 5c shows scenario 6 (non-Bristlecones) for the 1450 network from 1450 to c 1980.
Your link is to a press release, a non peer reviewed, and as far as I know, non accepted paper by Wahl and Amman.
It fails because the verification statistics failed.
I ask again, show me an peer reviewed paper that passes the verification statistics, that excludes Bristlecones, that graphs as a Hockey Stick.
Per, persisting with moving some pre-1450 deck chairs asserts:
"they do not show a statistically significant correlation"
Yeah sure, so says Steve McIntyre. I believe him.
"Your link is to a press release"
http://www.cgd.ucar.edu/ccr/ammann/millennium/refs/WahlAmmannClimaticCh… is not a press release.
"a non peer reviewed"
Peer reviewed for "Climatic Change".
"It fails because the verification statistics failed."
It passed verification statistics which you would know if you had bothered to read the paper.
"I ask again, show me an peer reviewed paper that passes the verification statistics, that excludes Bristlecones, that graphs as a Hockey Stick."
Shown. How about reading it and stop wasting everyone's time.
>>"a non peer reviewed"
>Peer reviewed for "Climatic Change".
I cannot believe you are arguing this. It was reviewed for climatic change, and rejected by the referees.
>>"I ask again, show me an peer reviewed paper that passes the verification statistics, that excludes Bristlecones, that graphs as a Hockey Stick."
>Shown. How about reading it and stop wasting everyone's time.
well, everybody agrees that the bristlecones show a good correlation with global/northern hemisphere temperatures over the last 150 years; I don't believe this is contentious. What is concerning is that they don't show a correlation with the recorded temperature in their locality; as McIntyre's blog post shows, and as confirmed by Graybill and Idso, who actually did the original work on these samples.
And on-topic for the NAS report, you will note that the NAS report found that a variety of verification statistics were required for the reconstruction. It also noted that MBH'98 fails dramatically on several of these statistical measures. Simply cherry-picking the one statistical test that it does well at is not sufficient...
toodle-pip !
per
""a non peer reviewed" Peer reviewed for "Climatic Change"."
"I cannot believe you are arguing this. It was reviewed for climatic change, and rejected by the referees."
Oh I see Wahl and Ammann are lying at http://www.cgd.ucar.edu/ccr/ammann/millennium/refs/WahlAmmann_ClimChang… . OK tell me where the truth is.
"that they don't show a correlation with the recorded temperature in their locality as McIntyre's blog post shows,"
Yes we can rely on McIntyre to do the right calculations.
"and as confirmed by Graybill and Idso"
What did Graybill and Idso actually say? If they're only saying the proxies shouldn't be relied on for a reconstruction that's not the same thing as saying there is no correlation.
"MBH'98 fails dramatically on several of these statistical measures"
which are not necessary or sufficient for adequate validation which you would have been aware of if you'd spent more time reading Wahl and Ammann and less time writing ill-informed opinions on blogs.
>MBH'98 fails dramatically on several of these statistical measures"
which are not necessary or sufficient for adequate validation which you would have been aware of if you'd spent more time reading Wahl and Ammann and less time writing ill-informed opinions on blogs.
yes, chris, that's why I said I lifted that conclusion from the NRC report.
"MBH'98 fails dramatically on several of these statistical measures"
So says the NRC report according to per even though this "dramatic failure" doesn't seem to stop the NRC having a high level of confidence in reconstructions after 1600.
"that's why I said I lifted that conclusion from the NRC report"
Knowing what an authority you are on the NRC report (which refers to Wahl and Ammann (in press)) and the literature in general it's rather strange how you came to the view that Wahl and Ammann's "Examination of Criticisms" was rejected. Who knows what other strange views you might have. Rather than continuing to attempt propagating such strange views it might be a better idea to try to become at least a little better informed and read what Wahl and Ammann actually have to say on the subject.
Dear chris, from the NRC report:
"⢠Large-scale surface temperature reconstructions demonstrate very limited statistical
skill (e.g., using the CE statistic) for proxy sets before the 19th century (Rutherford et al. 2005,
Wahl and Ammann in press). Published information, although limited, also suggests that these
statistics are sensitive to the inclusion of small subsets of the data."
"⢠There are very few degrees of freedom in validations of the reconstructed
temperature averaged over periods of decades and longer. The validation metric (RE) used by
Mann et al. (1998, 1999) is a minimum requirement, but the committee questions whether any
single statistic can provide a definitive indication of the uncertainty inherent in the
reconstruction. Demonstrating performance for the higher-frequency component (e.g., by
calculating the CE statistic) would increase confidence but still would not fully address the issue
of evaluating the reconstruction's ability to capture temperature variations on decadal-to-
centennial timescales."
So the NRC committee takes the view the multiple measures of skill are NECESSARY; in direct contradistinction to your view.
Toodle-pip !
per
From Wahl and Ammann (2006):
"EXAMINATION AND CONTEXTUALIZATION OF INTERANNUAL RECONSTRUCTION PERFORMANCE IN MBH
Tables 1S and 2S give r2 and CE values for the WA emulation of MBH and the MMmotivated scenario sets, which parallel the RE and verification mean offset performance reported in Tables 1 and 2. These data suggest (but see below) that a number of the MBH calibration exercises exhibit poor/very little skill at the interannual temporal scale in the verification period, although they all show very good skill at the multi-decadal scale of reconstructing the shift
between the verification and calibration period means. All of the MM-motivated scenarios exhibit essentially no skill at the interannual scale in the verification period, yet at the same time scenarios 5a-d and 6a-b exhibit very good skill for the 1450 calibrations at the multi-decadal
scale of the verification/calibration mean offset.
These results highlight the need to be very careful about the logical framework for determining the kinds of errors for which minimization is being sought in validation. To use, for example, just the interannual information available from r2 would, under the criterion of minimizing the risk of committing a false positive error, lead to verification rejection of most of the MBH/WA emulations and all of the MM-motivated scenarios reported. However, this judgment would entail committing large proportions of false negative errors for these reconstructions at the low frequency scale of the overall verification period, whose multi-decadal
perspective is the primary temporal focus of this paper. Our assessment is that such a rejection of validated performance at the low frequency scale would be a waste of objectively useful information, similar to that documented for micro-fossil based paleoclimate reconstructions that
use highly conservative criteria focused on strong reduction of false positive errors (Lytle and Wahl, 2005). Significant attention to appropriate balancing of these errors is now being sought in paleoclimatology and paleoecology (cf. Lytle and Wahl, 2005; Wahl, 2004), and remains an important venue for further research targeted at recovering maximal information in paleoenvironmental reconstructions.
It also must be noted that indirect verifications of the MBH reconstruction actually suggest quite good interannual performance, potentially raising the question of the quality of the truncated-grid instrumental values used for validation testing in the verification period (219 grid points versus 1082 grid points in the calibration data set). A spatial subset of the MBH annual temperature reconstruction for European land areas (25°W-40°E, 35°N-70°N) compares very well with an independent CFR reconstruction for that region, using a regionally much richer, fully independent set of different instrumental series in combination with documentary proxy evidence (Luterbacher et al. 2004; Xoplaki et al. 2005). Over the 1760-1900 period of this comparison, the r2 between the regional annual temperature averages of these two reconstructions is 0.67, corresponding with excellent visual temporal tracking of these time series (not shown) at interannual, decadal, and centennial scales. [The interannual amplitude in the European-based annual reconstruction is slightly greater compared to MBH.] Additionally, von Storch et al. (2004) show that the higher-frequency (interannual to decadal) tracking of MBH-style reconstructed temperatures with "actual" temperatures in an AOGCM context is very good, although an implementation error in the von Storch et al. analysis incorrectly showed very large amplitude losses for the MBH method at lower-frequency (approximately centennial)
scales (Wahl et al., accepted). Good interannual/decadal tracking is robust to correction of the implementation error (Wahl et al., accepted). These indirect tests of the MBH reconstruction add a significant caveat to the indications of poor interannual performance based on the verification
instrumental data used by MBH (and by us here). It will be an important area of further testing of the MBH/WA reconstructions to attempt to resolve this inconsistency of verification validation results for the interannual frequency band, which is an issue that is potentially relevant to all high-resolution proxy-based climate reconstructions because of the limited spatial representation of pre-20th century instrumental data."
So the NRC committee ignore most of what Wahl and Ammann have to say without giving justification.
One more thing, I cannot believe you used a blog post from McIntyre as a reference, i.e. a post from someone who has only ever had papers pubished in an unreviewed social science journal and a lightly reviewed letters journal.
>So the NRC committee ignore most of what Wahl and Ammann have to say without giving justification.
I am gobsmacked.
>One more thing, I cannot believe you used a blog post from McIntyre as a reference, i.e. a post from someone who has only ever had papers pubished in an unreviewed social science journal and a lightly reviewed letters journal.
That would be an ad hominem attack ?
A famous climate scientist tried the same trick, complaining that there had been an error of peer review when M&M published in GRL. Kind of sounds suspicious when he extols his own papers in the same journal as having passed the high standard of scientific peer-review.
Just out of interest, have you published anything in the "lightly reviewed" Geophysical Research Letters ?
yours
per
Re: "That would be an ad hominem attack?"
Is it if Chris O'Neill is just stating the facts?
The version you referred me to is not as far
as I know, the published peer reviewed version, it refers to itself as "in
press", and as far as I can see it contains several graphs
, but you do not refer to any particular one, so I don't see how you can
claim to have show the relevant graph.
Â
The only graph which refers to non Bristlecone
proxies is Figure 4. It is truncated, and ends in 1500. My guess is that they
didn't want to show the full timescale, as it would clearly not produce a
Hockey Stick.
Their paper still endorses the Mann et al
methodology, but has been overtaken by the following:
Â
From von Storch
press release following NAS report
Â
4) With respect to methods, the committee is
showing reservations concerning the methodology of Mann et al..
The committee notes explicitly on pages 91
and 111 that the method has no validation (CE) skill significantly different
from zero. In the past, however, it has always been claimed that the method
has a significant nonzero validation skill. Methods without a validation skill are usually considered useless.
http://www.climateaudit.org/?p=716
Â
Also:The conclusion to MM05a noted:
An obvious guard against spurious RE significance is to examine
other cross-validation statistics, such as the R2 and CE statistics, as recommended, for
example, in Cook et al.
[1994]. While there are limitations to the R2 statistic, the analysis
of statistical "skill" of Murphy [1988] presupposes that the R2 statistic exceeds the skill statistic and
cases where the RE statistic exceeds the R2 statistic are of particular concern [Cook et al., 1994]. In the case of MBH98, unfortunately, neither the R2 and other
cross-validation statistics nor the underlying construction step
have ever been reported for the controversial 15th century period. Our calculations have
indicated that they are statistically insignificant. (my comment..So
do Wahl etc in the paper you refer to in Figure 3 "Scenario 5d Network fail")
The MM criticism of the need to examine MBH98
cross-validation statistics was specifically endorsed by one of our GRL referees
as follows:
[they] also show that by not presenting other stringent
verification statistics (e.g. R2, CE, product mean test and sign test) the
validity of the 1400 step is likely much weaker than is apparent from the
original MBH98 study.
MM05b criticized not only the statistical
insignificance of the cross-validation statistics, but also the withholding by
MBH98 of adverse cross-validation statistics. Yet in section 1.1 "MM
Criticisms", WA omitted both topics and obviously failed to rebut them.
In their text, WA omit the very
cross-validation statistics that were at issue in the MM criticisms. This is
done without any notice to the reader of the omission. Although they have
withheld key cross-validation statistics themselves, they repeatedly emphasize
the need for cross-validation statistics, using language such as the following:
More generally, our results highlight the
necessity of reporting skill tests for each reconstruction model, as is
customary in quantitative paleoclimate
reconstruction. (p. 30)
A reader would be misled by the omission of
cross-validation statistics and by the many WA statements about verification as
he would have no way of knowing that WA had intentionally withheld standard
cross-validation statistics. http://www.climateaudit.org/pdf/wa.review.pdf
Â
"Kind of sounds suspicious when he extols his own papers in the same journal"
Yeah sure that's the only journal he bases his reputation on.
"I am gobsmacked."
A bit like what happens when someone says they "cannot believe" that someone else is referring to a paper that was "rejected by the referees" without even bothering to check that they are telling the truth.
"Just out of interest, have you published anything in the "lightly reviewed" Geophysical Research Letters ?"
Rather an ironic question in the context of accusations of ad hom.
"The version you referred me to is not as far as I know, the published peer reviewed version, it refers to itself as "in press"
If you thought about what the words "in press" mean, you might get some idea. It's an idiom for "in the printing press" which means the publisher has already decided to publish it and that means it has passed the peer review process.
"and as far as I can see it contains several graphs , but you do not refer to any particular one,"
Quoting myself: "Figure 5c shows scenario 6 (non-Bristlecones) for the 1450 network from 1450 to c 1980."
What part of the words "Figure 5c" don't you understand?
"From von Storch press release.."
When reading Von Storch bear in mind the mistakes his associates have made in producing paleo-climate models that they used to generate pseudo-proxies and also mistakes they made in making variations on the MBH98 method and variations on the RegEM method for producing reconstructions.
"The committee notes explicitly on pages 91 and 111 that the method has no validation (CE) skill significantly different from zero."
Like a lot of people, Von Storch makes the mistake of believing that a CE score of zero means the validation has zero statistical significance. A true rigorous significance estimation procedure is based on the null hypothesis of AR(1) red noise predictions over the validation interval, using the variance and lag-one autocorrelation coefficient of the actual NH series over the calibration interval to provide surrogate AR(1) red noise reconstructions. In other words the validation CE has to be tested against the validation CE you would get if you used noise of the appropriate statistics instead of the reconstruction in the validation interval. The validation CE of noise is normally quite negative. The MBH98 and RegEM validation CEs are higher than at least 95% of noise simulations so we can say they exceed a 95% significance level.
"In their text, WA omit the very cross-validation statistics that were at issue in the MM criticisms."
Pity this quote doesn't mention specifically what validation statistics they are referring to.
"A reader would be misled by the omission.."
Rather hypocritical thing for MM to say considering the omissions they made mentioning the extensive discussions by Wahl and Ammann regarding the interpretation of validation statistics.