"Dr. Michael Mann created this thing called the hockey stick, which purposted to show that late 20th century temperatures are warmer than they've been in a millennium. I don't think that's true -- a lot of people don't think that's true.... To get that result he had to eliminate....
"His big contribution was eliminating this thing called the Medieval Warm Period, when they had vineyards in Greenland, for example. The Medieval Warm Period is something I learned about at school. It was followed by the Little Ice Age where they were skating on the Thames, and this kind of thing, He eliminated all that and showed a flat line from the year 900 to the year 1900, and I think that's a lot of hooey."
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| from MBH99 (GRL) |
Or perhaps because it's not there. The recent huge (78 scientists over 7 years) PAGES 2k study didn't find it either. (Here is a great popular account by Stefan Rahmstorf.)
At multi-decadal to centennial scales, temperature variability shows distinctly different regional patterns, with more similarity within each hemisphere than between them. There were no globally synchronous multi-decadal warm or cold intervals that define a worldwide Medieval Warm Period or Little Ice Age, but all reconstructions show generally cold conditions between AD 1580 and 1880, punctuated in some regions by warm decades during the eighteenth century.Sometimes what you learned in school turns out to be wrong in the light of new data and methods.
Steyn also said he wrote an article for The Telegraph in 1999 trashing the hockey stick. (~17:30 - "I always thought it was a lot of nonsense.") I couldn't find that article, but I did find one he wrote in 2006 for The Australian, titled "Climate Change Myth," claimed to be reproduced here. Steyn called the hockey stick "this fraud":
Hence, the famous "hockey stick" graph purporting to show climate over the past 1000 years, as a continuous, flat, millennium-long bungalow with a skyscraper tacked on for the 20th century. This graph was almost laughably fraudulent, not least because it used a formula that would generate a hockey stick shape no matter what data you input, even completely random, trendless, arbitrary computer-generated data. Yet such is the power of the eco-lobby that this fraud became the centrepiece of UN reports on global warming. If it's happening, why is it necessary to lie about it?Can Steyn 's defense be that since he always thought the hockey stick was a fraud, his statement wasn't made with the knowledge it was false, and hence it's not defamatory?
That seems like a very thin ledge to stand on. How could anyone, not lest a writer for a major publication, use a definitive word like "fraud" without doing a good piece of research, instead of relying on what he learned in grade school? Did he wear blinders between then and now?
But maybe that's how it is in the conservative pundit class, where is seems to matter how fast you can pull the trigger and how pretty your hat is instead of how well you aim.
Update: In a post tonight, Steyn writes "I stand by everything I wrote...."
I'm not sure how well his defense will play in court. Steyn has written about the same topic over a period of 20 years, is cocksure to express a scathing opinion about it, but has not taken care or one minute of that time to understand the research he is badmouthing.
ReplyDeleteI assume Mike's team are collating evidence and can adjust their line of attack accordingly.
Vinyards. In Greenland.
ReplyDeleteThis just gets better and better.
One word: CENSORED. That's the name of the directory with run info without using the controversial SW US bristlecone pine series. Mann knew, yet he wrote that his results were robust wrt series inclusion/exclusion.
ReplyDeleteSpells fraud in my book.
What IS weird is that his non-centered PCA pulls out hockey sticks 95% of the time from random red noise (as verified by the North and Wegman commissions) , yet this time it did take the above bristlecones to do it.
@above: vinyards maybe not but farms in Greenland yes
Do you know what the word "censored" means in the context of Principal Component Analysis?
ReplyDeleteDo you even know what PCA is?
Did you read Mann's book where he explains all this?
Where do the North and Wegman reports say this?
ReplyDeletePlease provide a page number, and links to the documents.
@David Appell, yes I know what PCA is and I know what censored means in statistics (in my field of hydrology the issue comes up dealing with laboratory detection limits, e.g. <5 ug/l)
ReplyDeleteHowever, Mann's use of that word accords with the every-day definition, IMO.
Either way, he clearly knew, then lied.
No I didn't read Mann's book, sorry.
Page numbers? lol
Replication of Mann's non-centered PCA and use on random noise is in a whole dang Appendix to the North report.
The entire 1st half of the Wegman report is about Mann's flawed PCA.
What an old issue. Heck I don't *really* know if it was fraud or just bad math, just it's one of the two.
Joel,
ReplyDeletesince a lll you deniers have this startling proof of fraud for the last 15 years. It should be aslam dunk to get the paper retracted. Certainly this is as bad or worse than Wakefields fraud.
What is REALLY weird is that someone would go to the trouble of such an unethical unscientific act that could easily ruin their careers when that REAL data support the conclusion they wanted anyway.
How could they have known that all subsequent research would bear out their fraud, and that the only honest scientists are right wing libertarian's willing to stand up against ht socialist new world order, and that all the other competent people would say there were minor mistakes that had no real effect on the conclusions.
It is really sad that only the true heroes like you are left to defend the dignity of science these days
So you haven't read Mann's book.
ReplyDeleteGo read it. See what he says about the word "censored."
Then come back here.
Googling around I now gather what was in his book is that he was referring to his sensitivity analysis, randomly leaving out or "censoring" different tree ring chronologies. Not the word I would use even in a statistics context, but fair enough. I understand it and I learned something.
ReplyDeleteNonetheless it still showed the results were not robust, while the paper claimed otherwise.
Then there is the failed verification statistics, the infamous "Mike's Nature Trick" (which nobody describes correctly), and most fatally the non-centered PCA, which both North and Wegman found was effectively a Hockey Stick Generator. The "trick" only affected the most recent years (i.e., the divergence problem) but the other issues rendered the whole reconstruction meaningless. None of these issues were disclosed, either.
"Material" omissions, it seems, are allowed only in climate science and in quarterly reports by Lehman bankers :)
Tony: Good luck getting a hallmark AGW paper retracted, but at least a Corrigendum and a Supplementary Information section was demanded. Heck, didn't it take more than a decade for the Lancet to retract the Wakefield paper? There's still hope then.
Joel,
ReplyDeleteIt has been much more than a decade for the hockey stick.
also it is the most examined piece of science probably since Einstein. The wakefield paper is universally condemned by the "consensus" scientists, and wkefield has been unable to replicate his results nor has anyone else
I am no lower but I am guess that to actually do something fraudulent there has to be an intent and rationale for the fraud.
You are neglecting the motivation factor. WHY would you engage in fraud when the actual data supports your conclusions
there are a number of recent paleo reconstructions that do not show a global MWP, and Mann's error bars clearly do not prohibit some sort of MWP.
do you think that there is some evidence to show that Mann and CO tried some methodology that SHOWED a large MWP and make a conscious decision to throw that out and work until they found one that did NOT show it.
We even have STOLEN personal emails that would show ANY attempt to cover up fraud, and with the attacks on EAST angia being such a focus I find it hard to imagine that there would not be SOME slip or some defensive attempts to develop a strategy to hide the fraud from Mann
also I find it hard to beleive that ONLY libertarian and denier scientists would find that Mann's statistical use was so abhorrent, when pretty much no one else in the pale reconstruction field has made much of a big deal about it
You are implying that Mann's paper could ONLY lead to the conclusions that came form the paper no matter what data was put into it. I have heard this before and I find it hard to believe that if that WAS the case that the paper would NOT have been retracted as fraudulent. I do not subscribe to the hundreds of scientists conspiracy meme.
Even M&M specifically said there was no case for fraud.
What denier climate scientist HAS said that Mann's work was a case of fraud, and how have they backed up that claim.
My understanding is that statistics has numerous ways to approach problems and that there approach was not completely without merit.
My understanding is that scientists are not experts in every aspect of research that they do and it is not uncommon for them to employ methods in aspects of the work that a more expert person would not use.
and of course ALL subsequent research has shown the same huge increase in temps in the last 150 years, and more specifically in the last 40 years. that is the REAL issue of contention.
that is what Watts and the denialospher has been trying to undermine. As a practical matter the MWP has no scientific relevance, it is solely valuable as a propaganda point.
As David has pointed out form a scientific view a high MWP suggests a higher climate sensitivity than is currently accepted.
and it makes no difference if ACC does indicate the accepted science of a sensitivity of 2-3°C/doubling, because in 50- 100 years, the temps will blow away anything from the holocene,
pleistocene and start matching mid pliocene numbers in a time period unprecedented in 10's of millions of years.
the only place it makes SENSE for MAnn to fraudulently manipulate data is in current temps. and yet every climate scientist accepts that that part of his paper is in complete accordance with every other analysis of current temps.
Whereas Steyn is accusing Mann of fraud based on political attacks on climate science over the last 10 years or so.
I do think Steyn could use the excuse that he just believed the political attacks because he is an ideologue and is not interested in finding out the truth, but that doesn't seem to be a legal strategy that has much support.
Actually, the vineyards were in Britain. Where they are no longer. Due to Global Cooling, probably, but who knows? No one, that's who. We do not currently understand the factors driving climate, if climate is, in fact, even predictable. It may be chaotic.
ReplyDeleteWhat we do know is that, for most of the last million years, climates as warm as the current one were relatively rare, and seldom lasted as long as this one has already. So, what almost certainly lies ahead is another massive glaciation.
Jupiter,
ReplyDeleteI would have to agree with you. I personally predict another serious glaciation within the next 200,000 years
I would take at least two zeroes off of that number, but I agree it is open to debate.
ReplyDeleteDoes that mean you agree with me, that it is highly unlikely that the recent increases in atmospheric CO2 has altered the balance of whatever forces drive climate? Perhaps "highly unlikely" overstates the case. Let us say that the theory is rank speculation, and cannot even be evaluated until we have some understanding of what those forces might be. Agreed?
We do not currently understand the factors driving climate.
ReplyDeleteOf course, all of climate science says we do.
Jpiter,
ReplyDeleteNo I do not agree with you. I put that 200,000 year figure because eft to itself it would likely take that long for the atmosphere to remove enough CO2 for natural variation and other forcings to lead to a glaciation similar to the last ice age.
I certainly thin it is possible that there are unknown forcings or mitigating factors that will to some degree counteract the forcing of CO2. but as there is no hard scientific evidence supporting any candidate yet, I prefer not to "believe" in them.
I am quite confident that CO2 is a huge factor by increasing atmospheric H2O.
there could of course be biological feedbacks or clouds changes, or some event such a as huge volcanic explosion that could either limit or overwhelm the effect of CO2, but again in the former cases that is pure speculation and in the later case the destruction will be pretty bad and limited in time, so I see no point in pretending that ACC might not happen or be serious until there are actual reasons for believing so.
Could current relatively stable surface temps indicate something like this? yes, but the explanations that fit with ACC theory seem quite plausible, so it seems ridiculous to believe it means something else