1) Let's first note that it really doesn't matter whether the hockey stick shows that the late 20th century is warmer than any period in proxied history.
That's because climate today cannot be compared to climate then. Today's climate is subject to new, anthropogenic forcings that did not exist 1000 years ago. It's like comparing apples to oranges, and it has always been like comparing apples to oranges.
What really matters are today's forcings, and not those of a millenia ago.
2) Still, if you want to go there, we have been through years of suggestions (false, but suggestions) that PCA analysis is flawed and is statistically flawed. I have yet to have any real scientist tell me this, and everybody I've ever asked dismisses the M&M critique. In fact, nearly a dozen other independent analyses have found the same result.
The Tingley & Huybers result shows that the even a completely independent analysis shows the same result.
3) Now that skeptics have lost that front, we're supposed to believe that, no, it's the data that is flawed. The Yamal controversy, we know now, was manufactured all along, and in any case a few trees on a far northern peninsula could never have much of an effect on the conclusions.
Science is not about "auditing," and it has never been about auditing. It's about replication. IF skeptics like McIntyre want to be taken seriously, they need to go out and collect their own data, instead of writing endless letters to government officials complaining that someone won't play nice with them.
Of course, they never do that. They don't even try and apply for grants and explain why it's (purportedly) necessary. It's much easier to sit in your warm house in Toronto and send email all over the world than put your boots on and get to work.
And even if they could find no problems with the data, you can be sure that they would find plenty of other reasons to complain about it. After spending 8 years demanding that scientists give them their personal calendars, they would start dismissing any data taken on a Monday or Friday, because, you know, scientists were in a hurry to get back to their tents and make satellite calls home. Tuesday data would be rejected because the scientists ate chili that night, and we all know what that does to the intestinal tract.
On Thursdays, the phase of the moon was wrong.
There is, of course, no end to it, ever. That's important, because it's the first clue that ought to set off your bullshit detector, if you are intellectual honest.
And the reason, of course, is that none of the complaints are about science, or science would recognize them. (There has never been a contrary scientific idea in history -- ever -- that did not prevail -- and sooner rather than later -- because scientists are the ultimate skeptics and the scientific method promotes that.) It is, instead, about applying a Drudge-like approach to creating doubt by every and any means necessary.
20 comments:
Looks like Steve Mc is already eating your lunch!
http://www.climateaudit.org/?p=7502
Looks like your attempts ammount to the "white rabbit"
Anon, you are a moron if you believe that. You could certainly be a CA bot trying to game the discussion for the losers, which still makes you a moron.
Go git 'em, David.
Best,
D
David,
If tree ring temperature reconstructions are not needed to support AGW crisis positions then why don't you stop using them? The "science" here is so weak it casts suspicion on all AGW "science".
charleH
Ian Jolliffe! Considered the father of non centered PCA statistics. Tamino and others quoted and referred to him extensively for support of mbh98. Then Jolliffe finally posted on Tamino's web site and said the PCA statistics used by MBH98 are garbage. Go look it up yourself on Tamino's web site. And oh by the way look at Wegman's report. This post of yours makes you look incredibly ignorant and biassed.
David, seriously, you are becoming a bad joke. You need to understand what Wegman said about Mann's method. You need to understand what Joliffe did to Tamino's defense of Mann's method. You need to understand that most of the hockey sticks of recent vintage depend upon Briffa's utterly unexplainable choice of the Yamal series over the Polar Urals. The hockey stick is a hoax and you need to understand this soon or else risk embarrassing yourself further.
And Dano, remember when I told you that you have a chance to become a famous fool? All you have to do is stop restraining yourself as this oversimplified paradigm that CO2=AGW fails to explain the real world. Keep it up; tell us what you really think. Don't miss your chance. kim
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David, I am surprised you aren't backing off this one. You are backing a losing horse.
Per Climate Audit this paper by Tingley & Huybers uses Mann's PC1, strip-bark foxtails & Yamal. It even uses the van Engeln series which the IPCC AR4 dropped due to its splicing of instrumental & proxy records - a practice even Dr. Mann disapproves of. Garbage in, garbage out. Using de-centred PCA is nonsense, as Bouldersolar just pointed out.
I believe this paper hasn't yet been through peer review. But you boost it, and laud its conclusions. Do you apply different standards to paleo-climatologists than to Steve McIntyre?
Let's see: Naysayers are NOT in it for the grants. And they won't do the fieldwork that paper-pushers do (not sure what Tingley did here - didn't he just push the numbers that others collected? Isn't that what McIntyre did?
OK so I guess they are just 'spoilers?'
My next letter will be to a magazine called 'Scientific American' to ask why they only carry biased editorial writers.
Oh - that's because even if the science is wrong, it's the right conclusion - I know - heard that one before.
Perhaps they should just call themselves the 'American' magazine. The 'Scientific' part seems to be on the backburner.
Dr. Appell,
In (1) your first paragraph is nonsense, the explanation that follows notwithstanding. It matters very much (whether or not you "believe in" a MWP) whether or not the MWP does appear in the results.
As for the explanation that follows, you are begging the question. You are assuming the man made forcing are significant, equivalent to, or as you imply (apples and oranges) replacing the natural forcings.
In (2) what difference could it possibly make if any scientist whom YOU consider to be "real" has or has not told YOU whether or not they support M&M. Science is about truth - not about YOU. Also, Tingley & Huybers appear to be unpublished as yet.
In (3), science is in fact all about "auditing" in the sense of the need to try falsification.
Replication can be rather trivial - it happens every afternoon in a Freshman physics lab.
Everything below your "Of Course...." - well, that's just too embarrassing to comment on.
"...Science is not about "auditing"...
Really Dr. Apple?
Then what are all those peer reviews about?
So when the "audit" is done by the Hockey Team for the Hockey Team it is the gold standard of Science.
But when the "audit" is done by someone who is actually digging deap then suddenly he is a whiner, out of line, not entitled for the data, and is not a scientist?
Come on David. You are smarter than that.
As someone who uses PCA every day in his research (not climate science), let me try to clarify just that issue. Ian Jolliffe, a recognized expert on PCA has said
(in comment at Tamino's blog):
(1) Mann's uncentered PCA, while it has been tried occasionally by others, is a shot in the dark because (compared with centered PCA) it is no longer clear what is being optimized.
(2) conventional centered PCA may also be suspect for climatic time series because it is only appropriate for time series that are stationary. If we accept your premise that modern warming is not comparable to the past, then the time series is not stationary, and even centered PCA should not be applied.
When you suggest that no "real scientist" would question PCA as applied by Mann, you are simply telling us that you have not done your homework.
"Let's first note that it really doesn't matter whether the hockey stick shows that the late 20th century is warmer than any period in proxied history."
The Team is spending unbelieable energy in a series of papers for over more than a decade and in the venomous defense of those for something that "really doesn't matter".
So apparently it does matter to someone. A lot.
Indeed, what matter is the word "unprecidented". It is a very powerful word in any political context and the Team set out to establish that the warming is indeed "unprecidented".
"unprecidented" warming requires "unprecidented" political action.
The hockey stick is the primary tool for establishing this "unprecidented" warming and this is why it matters so much.
"we have been through years of suggestions (false, but suggestions) that PCA analysis is flawed and is statistically flawed."
you must be on a different planet to me. I don't know of anyone who suggests that PCA (the technique) is flawed; however, there are peer-reviewed papers that say that the application of PCA by Mann, Bradley and Hughes is statistically flawed.
"I have yet to have any real scientist tell me this, and everybody I've ever asked dismisses the M&M critique. "
You might want to speak to a statistician called Wegman, who produced a report for a congressional committee, and who made the same point. You might want to speak to Gerry North, who chaired a committee for the NRC, and who said that his report substantively agreed with the statistical criticisms made by Wegman. You might want to read the NRC report.
Alternatively, you can act like the three wise monkeys. Also, you have to be able to come up with cryptic comments, by sorting scientists into the real, and unreal; depending i guess upon whether they agree with you or not.
per
Mr. Appell
Is the online Scientific American report by you the revelation promised in your Sept. 30 item? I don't have the Nov. 2009 issue. I didn't get the October issue either. I bet it has something to do with these unopened envelope from SA somewhere in my pile. Isn't procrastination amazing - it works out so well sometimes.
You report something by two Harvard kids (sorry - I'm retired and more and more people look like kids to me). Something about two papers, which were submitted, somewhere, are in revision, and aren't even accepted, let alone published.
Mr. Appell - have you read these?
I haven't either! I can't say they are right or wrong. But you say they are right.
Oh for the good old days when Scientific American was respectable (When Martin Gardner was there - I guess), and when journals such as Science and Nature still at least kept their agendas hidden.
This is my first time visiting this blog. Do you write stuff like this often? It might be amusing for a while.
I was thinking about the statement that scientists "are the ultimate sceptics". Hmm. Most of the ones I know cleave to their ideas in the face of evidence to the contrary like shit to a blanket (remember phlogiston, anyone?).
Perhaps that's why Max Planck said that science advances one funeral at a time.
David Appell wrote:
Let's first note that it really doesn't matter whether the hockey stick shows that the late 20th century is warmer than any period in proxied history.
Here is the reason these reconstructions DO matter:
The primary evidence supporting the claims of AGW comes from the climate models. The modelers tell us that the ONLY way they can get their models to reflect the warming of the 20th century is to use a CO2 forcing plus an amplifying feedback from H2O. Hence, they conclude, man & CO2 must be responsible, because no other set of factors can generate such warming .
But there is a big potential problem with this line of argument. If the Medieval Warm Period (MWP) is real, and if its warming matches or exceeds that of the 20th century, then it is clearly possible that purely natural, non-CO2-related factors can cause such warming.
And if this turns out to be the case, it means the climate models must by deficient in some significant way. THIS is why there is such a non-stop effort to prove the validity of these reconstructions -- because the credibility and validity of the climate will be called into question if they cannot make the MWP go away.
You would do well, Mr. Appell, to spend some time reading Mr. McIntyre's posts at ClimateAudit.org before you dismiss them. You only make yourself look decidedly uninformed with posts such as this one.
I guess that Quark Soup is still remembered as a threat by the Climate Idiot types, David, which is sort of a back-handed compliment, if you like that sort of thing.
Always amusing (sort of) to be instructed upon the ends and means of science by accountants and such. It does go to show, however, that, while McIntyre has not been terribly successful at getting himself taken seriously by the academic climatological community, he's had great success at what, I suspect, he originally set out to do - reduce the autonomy of science as a social undertaking. So we hear "peer review's broken" coming from those who could never hope to be a peer in the sense that they mean and have been conditioned to think of it as the sort of mutual backscratching that you get on Bay Street, people laying down firm opinions on the proper use of PCA who've never used it or had any formal or informal instruction in multivariate stats, and "release the data" from the same lot who couldn't collect or anlyze quantitative data to save their own lives. But that's just beneficent fallout from what I think is the main point of all of this thoughtful-frowning, squinchy-eyed, chin-rubbing, pretending-to-be-a-critical-outsider shtick - the idea is that science should be subject to the same set of norms as business and politics, that data should be collected to serve an end, not test an hypothesis, that the motives, competence and honesty of anyone who comes up with findings that don't suit your agenda must be called into constant question. And he may have made a dog's breakfast of most of his "auditing" (Jesus, there you go, the whole atitude is encapsulated in the choice of that one word, the suspect is guilty until proven innocent, and we know that'll never happen, right, boys?), but he's done an excellent job of helping to undercut the one method that we've got for getting anything like reliable knowledge of the natural world.
- Lars
Hmm. This professional post-graduate engineer doesn't care for the lazy ad-hominem, Lars. Accountants indeed. It is precisely because I do generate & analyse data I get irritated by the sloppy standards of our paleo-climatologist friends.
You'll find the lazy back scratching at Real Climate. Lots of censorship & lack of civility also.
What we find from the writings by people like Lars and Dr. Appell is typical of those who have very little idea how science works. And Appell is supposed to be a science writer?
Such people seem to feel that only a climatologist can contribute anything that is valid, as though climatology is mainly something someone is trained in, rather than something that a person is currently doing. Regardless of Steve McIntyre’s training and past work, he certainly must be considered a leading expert on statistical modeling of climate, and certainly he is THE most knowledgeable person in the world with regard to available data bases – when he can get the AGW proponents to stop hiding it. And how can anyone work as hard as he does?
And then, Steve is subject to cheap shots – saying that he should go out and collect his own data – I guess drill all the trees himself. I wonder when the last time Appell got his hands dirty doing any real science was.
Re: Lars
"people laying down firm opinions on the proper use of PCA who've never used it"
See Ian Jolliffe at Tamino's
"the same lot who couldn't collect or analyze quantitative data to save their own lives"
See Starbucks Hypothesis at Climate Audit
"that data should be collected to serve an end, not test an hypothesis"
See Roseanne D'Arrigo's statement to the NAS Panel in 2006 that cherry-picking is essential to good climate science.
"the motives, competence and honesty of anyone who comes up with findings that don't suit your agenda must be called into constant question"
Sounds like a description of RealClimate.
Apparently it feels good to call other people idiots, but it won't earn you any respect or persuade anyone outside the tribe. If you have something of substance to say, I'm listening. On the other hand, if you want more rope, I'll give you as much as you need.
Huybers won a McArthur genius award this year. Not bad for a Harvard kid.
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