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Neither of those topics are high on my radarscreen to be honest; I don’t know much about them and I’m kind of tired of hockeystick discussions. I may point Wegman gate out though, as it deserves to be widely known. I read Tamino’s response to Loehle’s “vindication”. Not sure I’ve got much to add.
At RC this discussion came up before, and some back of the envelop calculation by Gaving showed that those heat sources are insignificant in the global radiation budget. I think they do affect local temperatures and thus contribute to urban heat islands though.
Bart, glancing at your Wegmangate link, I haven’t heard of Mashey before for some reason, but is this serious? In the executive summary (first six pages):
‘Some newspapers touted the Wegman Report and now the remake. Within weeks, The Daily Telegraph (UK), The Wall Street Journal, and The Australian all ran pieces in its praise, clearly competent PR.’
‘From start to finish, this entire effort was created to mislead the US Congress, the USA and the rest of the world.’
‘The WR was created to ratify and amplify MM+TT’s latest PR to mislead Congress and the public. It had two clear missions: #1 discredit MBH99 via statistical arguments, and #2 discredit climate science by mis-applying social network analysis.’
I like a bit of military-industrial complex stuff myself, but ……
A Barton staffer provided much of the source material to the Wegman team. The report itself contains numerous cases of obvious bias, as do process, testimony and follow-on actions. Of 91 pages, 35 are mostly plagiarized text, but often injected with errors, bias and changes of meaning. Its Bibliography is mostly padding, 50% of the references uncited in the text. Many references are irrelevant or dubious.
It has been key prop of climate anti-science ever since. It was promoted to Congress by Representatives Joe Barton and Ed Whitfield as “independent, impartial, expert” work by a team of “eminent statisticians.” It was none of those.
And how about this for a reference :
Valentine, Tom (1987) “Magnetics may hold key to ozone layer problems,” Magnets, 2 (1) 18-26.
WRT Loehle and Tamino. Tamino says, and Eli agrees that since the reconstructions are calibrated to the thermometer record from 1880 on, you cannot arbitrarily shift them up and down to achieve the best match over the entire proxy record.
What Loehle is doing shows, at best, how the variation in the reconstructions match. What he could legitimately do is calculate the cross correlations, but just eyeballing the various reconstructions, his is not going to do very well on that basis (OTOH neither will Mann o8).
Loehle’s reconstruction runs a fair bit higher for the MWP than the others (Mann, Moberg, Ljungqvist all being quite similar).
Looking forward to a post at WUWT entitled “Mann and Moberg vindicated!”
Obviously you are unfamiliar with the variance loss created by the regression methods in every OTHER hockey stick besides the Loehle one.. He used an evil and denialist process called average rather than CPS, EIV, TLS, or any other form of short timeframe regression. Pre-calibration amplitude based variance losses don’t occur with ‘average’ and time based variance losses are uniform throughout the plot.
Less variance loss, more amplitude. My calculations have shown that Mann08 had a 60 percent variance loss in the pre-calibration era.
So when you see Loehle running high, you should be spending more time considering the message in the math rather then worrying if a skeptical website will laud bad paleo work. His paper is absolutely simple, no place for tricks to hide the decline.
This is silly. It seems the folks at WUWT and AirVent have not even bothered to read Ljungqvist’s abstract, which contains this inconvenient fact:
“Our temperature reconstruction agrees well with the reconstructions by Moberg et al. (2005) and Mann et al. (2008) with regard to the amplitude of the variability as well as the timing of warm and cold periods, except for the period c. AD 300–800, despite significant differences in both data coverage and methodology.”
That is clearly a vindication of Mann08 and Moberg, not Loehle.
I also do not recall Moberg or Mann going “Ooh, ooh, look at me I’ve been vindicated!” after this paper came out. Loehle needs to grow up.
I have an idea. This finding by Ljungqvist is really bad news for CA et al., so how do they distract from that? Start a circus by making a ridiculous and unsubstantiated claim that they are the “victors”. Interesting.
Now of course partisan supporters like WUWT and AirVent buy into that, but that does not change the facts. Loehle’s reconstruction has many issues as has discussed elsewhere. Add to that this observation made by Ned at SS:
“Loehle manages to be both too warm and too early on the Medieval Warm Period and on the cool side during the Little Ice Age. This difference would not be all that noteworthy, except for the fact that Loehle 2008 is supposed to be a global reconstruction … and the magnitude of the MWP-LIA difference should almost certainly be smaller for a global reconstruction than for a Northern Hemisphere one.”
JMurphy – the Mashey piece I’m sure contains lots of good stuff as well as the ‘garbage’ I reprinted. My initial trust-detector just went haywire with the intemperate conspiracy language. But maybe that’s what you like, or maybe you can see clearly past/through it just to the science.
I wish people would stop talking about the “Medieval Warm Period” as if tree rings were the only sources we have to discuss its climate. There ARE written sources and they do not support the “warmer than the present” meme.
For example, Merrie Greenland, where the Norse allegedly had a high old time, consisted of two tiny settlements (about 6,000 people) hemmed in on the edge of the ice cap. There is no evidence of flora and fauna that suggest a warmer climate. North American Indians also tried to colonise Greenland on 4 separate occasions, and failed. Only the Inuit, with the culture best adapted for a cold climate, succeeded.
Vineyards in England? There are vineyards in England, Ireland and Wales today and have been for much of the 20th century, when the climate was colder than the last 10 years.
I am sure there is enough source material for a lengthy paper or book that correlates the temperature reconstructions with the historical record.
2) Boreholes also show a hockey stick. JeffID, how is it that direct measurements also show the same hockey stick as those resolved by Mann and others? It seems to be quite a stretch to think that all of these various techniques err in the same way as to end up with the same “wrong” picture.
Boreholes are terrible as a proxy. They are the worst of them all IMO. It’s like throwing bent hockey stick tea leaves in a tea glass and reading the result. The shape is determined by the nearly indeterminate matrix so you always get a similar shape. It is my only criticism of Loehles paper that it used some borehole measurements. BTW, whomever thought of using boreholes, should have consulted a geologist about subsurface waterflow. Even considering that heat might stay put in the rock for a thousand years requires a significant amount of LSD.
“It seems to be quite a stretch to think that all of these various techniques err in the same way as to end up with the same “wrong” picture. ”
That is exactly what I claim. I claim that these methods are demonstrably designed to make hockey sticks where none exist. I also claim to have done so with the simplest of the methods, LS fit and CPS. I did it this way so people who are less math inclined can try to figure it out and realize how bad the ugly stepchild of climate science really is.
Hey, I’m just an aeronautical engineer who posted the methods and code on line so anyone can do it. You don’t have to take my word, but you do need to have enough skill to run turnkey R code and follow the steps.
I’ve done enough work on it to estimate Mann08 variance loss at 60 percent of the calibration period. Ljunqvist, Christiansen, VonStorch, Zorita all discusses this variance loss as well. Variance loss is polite speak for hockeystickizatoin.
Which reconstruction do you think is best and why?
If all of these hockey sticks are so poor, why do all the paleo folks keep using that technique? Surely, they know how to read your code and others’. Are they all conspiring, stubborn, or just igonorant?
Actually, there has been quite an awakening in the climate community about these issues in recent times. There are still those like Mann who have careers based on the methods. There are guys who publish sticks with bland comments like variance loss with little effort to quantify the effect, others have published regarding methods to ‘improve’ the problem. Most climate scientists I’ve communicated with know the problem is very serious and would rather just not deal with it.
So when you ask why they keep publishing junk? Not all of it is junk, Christiansen had some excellent mathematical treatment of the issue. The recent Lasso paper, was criticized for exactly this problem – none of it has the right answer.
Of course if you want to know motive, everyone has their own reasons, Mann’s inner circle are the only ones who haven’t admitted this problem exists but after tiljander he’s pretty well willing to do anything to defend his sticks.
Unfortunately the problem is caused by the methods of sorting. The only way to fix it is to quantify the variance loss and rescale the historic portion of the graph in comparison to the calibration period. Of course, if properly rescaled, that means modern times won’t be quite as high as some of the historic signal – in most cases. It won’t exactly make modern times low though either. What it will also mean is that the mannian conclusions about warmest in two thousand years will be unsupportable, and that is a big catch line for the IPCC political group.
Bart probably wasn’t aware that Dr. Loehle avoided the problem completely by ‘averaging’ pre-calibrated proxies. Mathematically speaking, it’s the best paper for that reason. Reduced pre-calibration variance loss, and the highest pre-calibration temp. hmmm. Really climate science should take this more seriously.
When I first read it, it actually gave me shivers because I thought I was actually looking at historic temperature for the first time. Then I learned about boreholes – oh well.
Scott, I clicked on your Wegmangate link and found this statement as the second paragraph:
‘As detailed in John Mashey on Strange Scholarship in the Wegman Report, the Wegman report was a facade for a PR campaign well-honed by Washington, DC “think tanks” and allies, underway for years.’
Do you really believe that stuff? McIntyre is a stooge, or worse? They are all, in the end, in the pay of big oil?
I accept that there is a system, Wall Street and so on, a tacit capitalist conspiracy if you like, but its power has been used to attack The Hockey Stick in a coordinated campaign, for years, SOLELY to defend their profits? Really?
For the record, these are John Mashey’s words but I do agree. I should have used quotes.
Also, for the record, I do not think Steve McIntyre is a stooge for big oil, or if he is, he does not realize it. Steve seems to like to be the guy who tries to make scientists look bad so he will look better. You know, stand on people to look taller. He needs to learn how to behave like a scientist if he wishes to be viewed like one.
The attack on the hockey stick is to make scientists look evil or incompetent in order to make people believe that all of climate science is the same. Why? I detail a few reasons here.
It is money and it is ideology. AGW threatens both. Kill the messenger if you do not like the message.
Barton is ABSOLUTELY protecting the fossil fuel industry. He is not even trying to hide that.
I come from science. I see nothing that refutes AGW as the primary driver of warming and I tend to trust a hypothesis when just about every expert from a wide variety of fields agrees.
“Boreholes are terrible as a proxy. They are the worst of them all IMO.”
That may be true but that is just your opinion. Good grief, just how many proxies are there out there which all have a HS-shape? That was probably Scott’s point. Anyhow from Ljungqvist’s paper:
“A way to assess the low-frequency temperature variability, without the problems associated with calibration of proxy data to the relatively short instrumental temperature record, is to reconstruct the temperature history from composites of borehole measurements from the Earth’s crust. Such reconstructions only show temperature variability on very long time-scales – centennial and longer – and the temporal resolution furthermore decreases back in time. They are, however, rather reliable on centennial time-scales for the last millennium and they indicate a considerably larger amplitude (i.e. magnitude of cooling during the Little Ice Age) of temperature variability – c. 0.8–1.2°C – for the Northern Hemisphere than most other large-scale proxy reconstructions (Shaopeng et al. 2000; Huang et al. 2000, 2008; Huang 2004).”
But I though that you liked the larger amplitude reconstructions? Then again,
“However, the reliability of the amplitude of temperature variability from borehole measurements is under discussion and has been called in
question (González-Rouco et al. 2009).” [Ljungqvist (2010)]
Oops, there goes your beloved amplitude. Anyhow, if Loehle is correct, and that is a HUGE IF, then that does not bode well for those advocating for a low equilibrium climate sensitivity. I do not see any way how this is “good” for the ‘skeptics’, and just points to the incoherence of their arguments.
“I’ve done enough work on it to estimate Mann08 variance loss at 60 percent of the calibration period.”
You are repeating yourself. Keep saying it over and over is not an argument, nor does it make it correct nor convincing.
With that said, here lies the rub. And I will spell your logical fallacy out clearly for you. You believe that the Ljungqvist paper “vindicates” Loehle, but it is a closer match to Mann08 and Moberg, you cannot deny that. But you suggest that Moberg and Mann08 suffer from “variance loss in the precalibration period”. Thus, using your logic, Ljungqvist’s reconstruction likely suffers from the same problem (it does agree very with those supposedly flawed reconstructions after all). Now here is the kicker, you and Tony and Loehle and others are claiming that this “flawed” (again, applying your logic) reconstruction vindicates Loehle’s work.
So, if Ljungqvist is right, then Loehle is clearly not vindicated, in fact, Loehle is shown to be an outlier. If Ljungqvist’s reconstruction has the same flaws as Mann08 and Moberg (as your logic/reasoning above clearly suggests), then it can not be used to vindicate Loehle.
That is the problem with trying to deceive people Jeff, it only works for a while before you trip yourself up.
“Hey, I’m just an aeronautical engineer who posted the methods and code on line so anyone can do it.”
So you admit that you are not qualified to speak to the climate science. Now how about your tell us all if Ljungqvist’s reconstruction also has “variance loss in the precalibration period”……
Either way, Loehle has not been vindicated, to suggest so is pure spin, not to mention misrepresenting Ljungqvist’s findings. And please tell Craig the next time he tries to do a reconstruction to please do it is such a way that permits easy comparison with thermometers and other temperature reconstructions.
The criticisms of the various paleoreconstructions are very much justified, what is odd is the amazing defense of it. .
You are a professor by your link so you should be able to see the problem with correlation based sorting of noisy data. What do you think? Am I just lying or my computer has a bad math processor or is there some other magic trick I’m pulling? Maybe big oil is paying me? Or I’ve successfully tricked thousands of technical readers by hypnosis through my amazing command of punctuation. :)
With utmost respect, you are either ignorant of the facts, being deliberately obtuse or are incredibly naive. Barton receives many millions of dollars from FF companies/interests, that is not speculation it is on the public record.
I’m sure if it were a climate scientist against who such concrete evidence of misconduct had been gathered you would be all over it.
Anyhow, forget all the ‘alleged’ conspiracies for now. How about you focus on the fact that Wegman et al. misled congress and committed plagiarism, amongst other things. And McIntyre and McKitrick had a hand in the Wegman report too it seems….
I’m sure that you are a man of principle and ethics, so why do these remarkable revelations not concern you?
Boreholes tell a nice skeptic story if you are the type to hope or want a certain result. They make the hump in the MWP.
It is not usable data though.
Now how about your tell us all if Ljungqvist’s reconstruction also has “variance loss in the precalibration period”……
How about if the author does it:
Fredrik Charpentier Ljungqvist says:
September 28, 2010 at 7:16 am
A comment from the author:
Some remarks have been made suggesting that the amplitude of past temperature variability are deflated. It is indeed true and discuss in length in the article. The common regression methods do deflate the amplitude of changes in the reconstructed temperatures. This reconstruction shares this problem with all others.
I’ve been very patient with you Maple, read carefully, try and learn something.
You have been patient with me? This is the first time you addressed me on this thread. Talk about straw men.
Anyways, thank you for demonstrating and showing for all to read here that Ljungqvist cannot be used to vindicate Loehle. Funny how you and the mob at WUWT are blind to that inconvenient fact. The incoherence of your argument and logical fallacies continue….
Really, you think you are too clever Jeff, read my earlier post again carefully. This is a no win for you. And Craig was way out of line claiming that Ljungqvist vindicates him.
“Anyhow, forget all the ‘alleged’ conspiracies for now. How about you focus on the fact that Wegman et al. misled congress and committed plagiarism, amongst other things. And McIntyre and McKitrick had a hand in the Wegman report too it seems….
I’m sure that you are a man of principle and ethics, so why do these remarkable revelations not concern you?”
I don’t know the details of this problem. I saw Deeps initial post on it but didn’t follow up. The reason I’m not concerned though is that I am not math illiterate and Wegman was right.
Scott – yes, I thought they were your words, I was confused. You appear to be baffled how anyone can be sceptical or oppose action on climate change (it’s so obvious) without some axe to grind, either personality (McIntyre) or financial (the rest) or presumably mad (Jeff Id). I think you’re wrong about all that, but we probably won’t ever agree. :)
Mapleleaf, can I have some of what you’re on?
‘Barton receives many millions of dollars from FF companies/interests, that is not speculation it is on the public record.
I’m sure if it were a climate scientist against who such concrete evidence of misconduct had been gathered you would be all over it.’
You really will have to explain how sentence 2 follows from sentence 1.
The new leader of the Labour Party in the UK was elected by significant trades union support, the same unions that fund the Labour Party. The Conservative Party is funded by business and rich individuals.
That is a reason to keep an eye on their statements and policies, to check that they have some independence of thought and action from their financial supporters.
It is also likely that their policies, presumably through belief rather than venality, will not be opposed to the interests of their funders, so statements and policies that appear to favour their supporters are not in themselves suspect.
I’m not sure at what point this becomes ‘concrete evidence of misconduct’, nor where I am being either ‘obtuse’ (watch out there, I’ve seen Shawshank Redemption you know) or ‘naive’.
“You really will have to explain how sentence 2 follows from sentence 1.”
You really do need to read the evidence presented John Mashey’s report. For example:
“It [the Wegman report] was promoted to Congress by Representatives Joe Barton and Ed Whitfield as “independent, impartial, expert” work by a team of “eminent statisticians.” It was none of those…..A Barton staffer provided much of the source material to the Wegman team.”[Mashey]
Anyhow, sentence one refers to Barton et al. and the huge sums of money he has received form FF industry (I’m not entertaining you straw man about unions in the UK] as shown by Dr. Mandia. Now you should know that Barton solicited the Wegman report and he or his aides assisted in said report and provided information, and that he promoted the report. Said report has plagiarism etc. etc. etc. Now, had some someone found such damning evidence against a climate scientist as has been found by Mashey against Wegman and colleagues and grad students, I’m sure that the ‘skeptics’ (you seem to fit the profile, or at least your comments thus far) would be hopping up and down and frothing at the mouths– they have done so based on much, much less information, and even for fallacious statements floated on the blogosphere.
And if you want to know what I’m on, nothing. Although I was just about to have a coffee break (fair trade, organic, shade grow– you know, the good coffee ;)
Yes, ShawShank was excellent, but please don’t have me taken out or take yourself out ;)
I do not wuestion how people have differing views on adaption and mitigation. I just do not understand how people can claim that there is no AGW or that AGW is a minor player.
As long as that attitude persists then there can be no reasonable action. Why act of there is no problem?
MapleLeaf, JeffID has always been respectful with me, but I do appreciate your concern.
I am sure that JeffID knows more than I do about reconstructing T but I am not so sure he knows more than those publishing in the field. When I am unsure I try to figure it out. If I have trouble there then I go with the scientific consensus until I see otherwise.
I see hockey sticks from a variety of proxy data using a variety of techniques so I tend to think there must be some truth there.
Well, I’m certain you’ll agree that detonating school kids, footballers and movie stars into gory pulp for ignoring their carbon footprints is attention-grabbing. It’s also got a decent sprinkling of stardust – Peter Crouch, Gillian Anderson, Radiohead and others.”
10:10 Campaign – What on earth are they thinking!!!!
Is that really supposed to persuade people!
Stay with it until 1min 10 seconds, and the red button..
(a school setting, of course, with children, then watch the rest, in fascinated horror, this makes the ‘Bedtime Stories’ pr video, look like a .. bedtime story)
Of course I don’t claim to know more. I am an engineer and we tend to be meticulous about our numbers. Assumptions, when made, really need some verification. In the past year, climate science in general has spent quite a bit of time studying and recognizing variance loss. A topic I’ve been blasted for (mapleleaf style) by many since the Air Vent started is now becoming mainstream knowledge.
I really have laid it all out in an incredibly simple way – see hockey stick posts at tAV. If first you try to figure it out then you go with consensus, I’ve given a good spot to start from. And the consensus is shifting these days – because it has to.
the Ljungqvist quote says
This reconstruction shares this problem with all others.
From the prof himself — “All others”, not just some. Where climate science hasn’t gone far enough is in the realization that papers like Mann08 have not just variance loss but BIG variance loss. I estimated 60 percent loss.
This is exactly the claim I made when we started our conversation above!!
I am puzzled by your statement that Mann ignores the problem of variance loss. He has published several papers benchmarking various methods, including his original method, against synthetic proxies. These papers (Mann et. al. 2005, 2007) document the amplitude loss. While the original method has been shown to be quite a poor performer (and indeed the loss may be 60%), subsequent methods perform quite a bit better although they all suffer from some — although not nearly as much as you claim — suppression of variability.
So Jeff, for the lay person, are you are stating that due to a large variance loss from every reconstruction technique of every type of proxy, there will be almost always be a hockey shaft? Then, once the observed temperatures are grafted onto the end of the shaft they will show a blade? The end result being a hockey stick regardless of proxy and technique? Even with boreholes that are actually measuring temperature gradients (no proxy data)?
The methods sort for preferred information in the calibration range — all of them. This amplifies the accidentally preferential noise in the calibration range in preference to the unsorted pre-calibration noise. The result is that the pre-calibration noise cancels due to randomness while the sorted noise in the calibration range adds – canceling noise having been thrown out(CPS) or deweighted (other regression methods).
Really it is the result of people honestly trying to dig out an impossibly weak signal from unsuited proxies.
I’m regularly amazed at the lack of rigor in comparison of different methods on red noise. Recently the Tingley criticism of MW10 on variance loss claimed a better result using different methods, yet didn’t show the other methods? I agreed with many of the critiques.
Better result is still not the ‘correct’ result nor is it necessarily a good approximation of the correct result. And better result in paleo, needs to be demonstrated.
We see those who haven’t done the math claiming unprecedented temps in 1000 or 2000 years all over blogland. They don’t realize that all of these sticks are primarily mathematical artifacts. It is a real problem with real criticisms. It is also curable but ARIMA matched data followed by a brute force rescaling is my best idea so far.
Will they all have 60 percent loss? No way, deamplification is data dependent. But when you say, warmest in 1000 years, remember, the historic data has been deamplified by some amount and that is why Loehle’s simple average shows lower lows and higher highs.
Yes, I understand some of what you are saying and I did not mean I was the lay person. :)
I meant what could I (or anybody else) tell a lay person about why you and some others believe that hockey sticks regardless of proxy and technique. Essentially, simply your very last comment so that the average person understands. No jargon, no assumed math background.
Temperature proxies are millenia long series of suspected but unknown temperature sensitivity among other things (noise). Other things include moisture, soil condition, CO2, weather pattern changes, disease and unexpected local unpredictable events. Proxies are things like tree growth rates, sediment rates/types, boreholes, isotope measures etc.
In an attempt to detect a temperature signal in noisy proxy data, today’s climatologists use math to choose data which most closely match the recently thermometer measured temperature (calibration range) 1850-present.
The series are scaled and/or eliminated according to their best match to measured temperature which has an upslope. The result of this sorting is a preferential selection of noise in the calibration range that matches the upslope, whereas the pre-calibration time has both temperature and unsorted noise. Unsorted noise naturally cancels randomly (the flat handle), sorted noise (the blade) is additive and will average to the signal sorted for.
The blade of the hockey stick is the sorted signal and noise in post 1850 times, the handle has a flattened shape due to the canceling of the noise. The difference between the blade and handle is referred to as variance loss.
Even though I am certain this is one hundred percent correct, this changes little about the climate story. What it does do is make one wonder how math skilled individuals still refuse to acknowledge it. What pressures exist in climate science that people can’t just say, no, that’s not right, take it away from the good work.
BTW, I used to like the concepts of boreholes. They were my favorite for a short while because you are actually measuring temp. I began to ask a few questions and soon found that boreholes weren’t dry, aren’t homogeneous soil/rock and were not drilled for temp but rather for water etc. Water has an amazing way of cooling stuff down. To imagine that there is a historic climate signal in wet boreholes takes a serious amount of self sophistry.
Thanks for your round-up comment at 4:22; that’s useful.
To me it sounds entirely reasonable to weigh the proxies based on how well they reproduce the instrumental temperature record. You seem to assume a good correlation over this period is based on noise, i.e. coincidence? Or at least, that noise could have contributed to the good correlation, which is fair enough. (With sorting, you mean weighing, right? (giving it more weight, i.e. importance, in the final reconstruction) )
You argue that inasfar as by coincidence the noise correlated with the measured temperature increase since 1850, that takes care of the upswing in the proxie reconstruction (the blade), whereas the pre-1850 proxies have random noise which causes the flat shaft.
Is that good paraphrasing of your position?
In that case the critical point is really, to what extent is a good correlation between measured temperature and proxies coincidence (ie not due to a causal relation between the proxie and temperature), and to what extent is it due to a real causal relationship? Inasfar as the latter dominated, there shouldn’t be a problem.
This could -and I think has- been investigated by people studying the actual dynamics of the proxies involved, eg plant physiologists for tree proxies (Jim Bouldin frequenly mentions this at RC).
It also shows that in the end, finding statistical relation still has to rest on physics (or chem or biology) in order to be properly interpreted. I take that as some sort of vindication.
And quite interesting that you alude to the fact that small temperature variability in the past would be consistent with a low climate sensitivity and large past temperature variations would be consistent with high climate sensitivity. This is of course only the case if all else is equal, which it is not, but still. It’s a point I’ve also brought up before, as it is a funny mixing up of tribalist thinking in a way.
You say “The difference between the blade and handle is referred to as variance loss.”
Hang on….so playing devil’s advocate here– if the warming in the last 130 years is unprecedented over the time of the reconstruction, isn’t the noise and perhaps limited variability in the past say 2000 years going to be dwarfed by that?
I’m not sure if I’m being terribly eloquent here…sorry if I am not. I guess that if the variance is calc. relative to a huge anomaly, then off course it will give the impression that that the variance prior to that significant benchmark anomaly was low. So is that loss of variance in itself not an indication of the fact that what is happening now is significant? Doing it that way seems to induce an inherent bias.
And for the record I am honestly trying to learn here and not argue. So I hope we can both check our snark at the door….I’ll try but I am terse by nature.
I can’t follow your latest post. Everyone I speak to calls me Jeff BTW.
Variance exists throughout the series – pre and post calibration. What we need is both to be equal so we can see the sensitivity of climate.
By the way, since you are obviously very much concerned about the implications of high natural climate variance, the believers get to trade unprecedented in 2000 years for even higher climate sensitivity.
Of course there is much to debate there as well but at least the line of discussion moves on to a more reasonable front.
Sorry, Fred Pearce says you are called Patrick Condon. So Jeff it is.
Anyways, like I said, I was concerned I was not communicating clearly, but I was honestly trying.
“Variance exists throughout the series – pre and post calibration. What we need is both to be equal so we can see the sensitivity of climate”
But the way the variance is calc. now it is relative to the instrumented record, and why would the variance be ‘conserved’ or remain the same with time?
“the believers get to trade unprecedented in 2000 years for even higher climate sensitivity.”
I asked politely to check snark at the door. I am no more a ‘believer’ than you are a ‘skeptic’ or ‘denier’. There is no ‘faith’ in the radiate forcing of GHGs, as someone concerned with facts and data, surely you can appreciate that. Or are you a “believer” in aerodynamic resistance or drag coefficient or g?
So am I right that if Loehle is right, then you are saying EQS is probably higher than the data suggest. BTW, what do you think the EQS (not transient climate response) for doubling CO2 is?
Any thoughts on what Didactylos said, or on Ned’s findings?
Maple, I couldn’t agree more with Bart’s comment re Jeff’s handle. When Jeff politely asked you to refrain you upped it. That is just weird.
My UK examples were not strawmen. Donors give money to politicians whose views they like. Politicians declare these donations. Politicians then execute their views. That these views often happen to suit the donors should not be a big surprise. Concrete evidence of misconduct is just silly.
Jeff – your 4.22 comment the clearest I’ve read on the subject, and I look forward to your reply to Bart’s reply. For me the critical issue is to recognise how noisy the proxies are to start with, and the entirely reasonable process of post-1850 calibration does not necessarily leave you with very much you can rely on.
‘Roddy, I do not question how people have differing views on adaption and mitigation. I just do not understand how people can claim that there is no AGW or that AGW is a minor player.’
I can’t remember how we got here, but here goes:
a) Hardly anyone claims there is no AGW, certainly not Watts, McIntyre, Id, Lucia, Mosher, Uncle Tom Cobbley and so on. Yes, I’m sure Monckton does, but who cares.
b) ‘people … claim ….AGW is a minor player’
That’s complicated – do you mean:
1 People think it won’t be as bad as you do, ie, for example, it will happen at the low end or even below the IPCC projections, the impacts will be not that bad and adapted to anyway as we go, and so on, or
2 AGW is a minor player compared to all the other things we could be doing to improve man’s lot in a sustainable way, like hunger, genocide, literacy, freedom, malaria blah blah, and the mitigation policy responses proposed will WORSEN all these other things, which needs taking into account.
I certainly have a hard time rejecting 2 too easily?
1 is really a question of the quantum of warming, then measuring the impacts. Am I alone is finding the work done on impacts unconvincing? The only bloke who isn’t convinced the Maldives are going under?
You have not shown me that I am wrong on models, you have not shown that I was wrong about the Metoffice, you have not shown that I was wrong about NOAA. I will not like the outcome of any research when it complies with my ideas. I need facts. You do not give me facts, you give me distorted views.”
Well, Harry, I cannot argue with anyone who, after I inform him he makes false claims when he says climate models do not include albedo, water vapor, ozone and solar influences, then just plainly dictates for all that I did not show you wrong on models. It is completely and utterly useless to debate with you, other than show others what we are up against when trying to deal with disinformation.
Or, to quote Bart himself:
In climate science, it is “how do we keep up with ignoramuses bringing up zombie arguments?”
My middle name is Jeff and while I appreciate Bart’s intent to keep those who reasonably fear the public anonymous, after the papers outed my full name and address in the UK to make a story, I’m hardly anonymous. BTW, I very much believe the information came directly from British anti-terror police.
As to your questions about sensitivity Bart or someone else is better suited to answer that question. It was a point that Eric Steig made at tAV to which my only reply is that we don’t get a choice in that matter, if higher sensitivity is the case we probably want to know about it.
“On climate blogs, no one can hear you scream”. Re: harry: arghhhhhhhhhh!
Harry should read Ch. 8 of 4AR (or is that AR4) WG1. He could also take a look at all of the papers describing GISS Model E on the GISS site, but that would be a lot of work and take a certain amount of intelligence.
“To me it sounds entirely reasonable to weigh the proxies based on how well they reproduce the instrumental temperature record.”
Barring an unrealistic calibration by physical process in a controlled environment, there aren’t a lot of other choices. Mathematically, it is a very interesting problem – I get excited about the dumbest things. We have proxies that all are assumed to have different responses to temperature so each response should have a different multiplier. I’m forced to say that there isn’t any other choice, but the problem is what effect does that choice have.
For future reference, this link is the whole story behind the next graph:
I placed a signal inside rednoise and used CPS to extract it. By saving the scaling coefficients I was able to generate iso-temperature lines for the distortion caused by preferentially sorting noisy signals.
You can see that while looking for an upslope signal, I’ve created variance loss in the historic signal which used to have an equal amplitude to the upslope. The shape of the signal in this case was a sine wave in history and a triangle wave in the present. From the first link above you can see the amplitude of the sine wave is cut down by about 50% in relation to the blade. Unfortunately, I didn’t rescale the whole plot to make it fit the red line after it was done. This makes it confusing for some, but if technical readers read the text it will make sense.
This answers a couple of questions above. First, you ask if the correlation is purely accidental and by noise. The answer is yes partially, but not necessarily completely by noise as noise with a strong signal also creates the problem.
The second question you asked was whether I assume good correlation is based only on noise, to which the answer is no, noise plus signal as you have suggested.
“Is that good paraphrasing of your position?” — yes it is very close.
“In that case the critical point is really, to what extent is a good correlation between measured temperature and proxies coincidence (ie not due to a causal relation between the proxie and temperature), and to what extent is it due to a real causal relationship? Inasfar as the latter dominated, there shouldn’t be a problem. ”
This is also a point on which we agree. In Mann07 the author shows little variance loss by these methods. It was very much disturbing to me. When I met Steve McIntyre this year, it was one of the main things I wanted his insight on but he didn’t know either. What I found was that Mann was assuming a very very low level of autocorrelation in the data. If I use his numbers, i agree that CPS, EIV and any other weighting method I’ve tested will cause near zero variance loss. But the values are incredibly unrealistic and should never have passed peer review. The Mann07 paper is no good.
So I went back to work and fit ARMA models to the Mannian data. I got a histogram of values for the different proxies and used that histogram to make 10000 series of AR matched noise. The algorithms are canned ones in R and the code is on line. I used Mann07’s model series and added it to the noise and ran CPS on it.
Using the same CPS correlation coefficient threshold as in M08, I adjusted the SNR until I retained 40 percent of the proxies, again matching M08.
All reconstructions had excellent correlation to the original signal in the blade range. The surprise to me was that to retain 40 percent of the proxies only required a 7 percent SNR. Now this was the primary argument for a signal to even exist in M08. 40 percent proxy retention was far higher than 13 percent expected by accident. In actuality, the random noise retention was very close to 40 percent by itself when more correct rednoise estimates were used. Even worse, there are a few other details in M08 which would push the random noise retention right up to 40.
Basically, this post shows there is very low SNR (temperature signal) in the proxy data – which in this case was primarily trees.
I was more than a little surprised by the result and have had a lot of time to consider it. Even if I’ve done something wrong to overestimate red noise or whatever detail, the answer is not even close to the claims in mainstream paleo.
From this calculation, I was able to conclusively estimate that the variance loss in M08 is on the order of 60 percent, there is very little temperature signal in tree ring data and the M08 hockeystick is almost purely an artifact of the math. My belief is that Mann is not alone in this error either.
Now as an unpaid, non-professioinal, I’ve really got very little personally invested in being right on this. If someone were to show me my errors, it would be relaxing at this point because it feels like fighting against the world. You should see how hard it is for guys like us to publish a correct Antarctic temperature plot or correction to Santer.
I really don’t think anyone can show it is significantly wrong though.
In the end, paleoclimate needs to do a serious study on rednoise matched data for various methods to determine if there is a significant difference between any of them.
Finally, if I use Mann07 rednoise, I get near zero variance loss as his paper shows, but retain nearly 100 percent of the proxies in CPS – totally unrealistic and a complete proof that his 07 paper was non-physical.
I removed the extra bolding. Will respond to your points later this weekend.
You’re correct, but I do sense some tribalism here. Anonymous commenter “VS” also went out and about outing Tamino, the irony of which was not commented on by “your side”. Anyway, that’s all juvenile game playing that I can do without.
Scott, for a lay person, how about this, say you have 20 trees, and 3 of them show hockey sticks, 3 show the opposite, and 14 are flat. Is it OK to just select the 3 that show hockey sticks and average them together?
That’s actually not what Jeff is saying, but a simplification.
MapleLeaf, your argument on vindication makes no sense. Mann was attacked by many skeptics, and then he claimed vindication based on papers that used different methods and showed somewhat different results.
MapleLeaf: Actually, what SM said was entirely appropriate. As Jeff is trying to explain, the paleo literature isn’t terribly good. There are problems with a lot of the reconstructions. There really isn’t much (if any) that can reliably considered climate signal.
Without good paleo reconstructions, how does one compare current temps to past temps with any reasonable validity or reliability? How does one know if there’s a big problem, a little problem, or a medium sized problem? The only scientifically supportable answer is, we don’t know.
What weak argument. And I see the McIntyre fans have arrived…I thought you were all uncritically singing his praises at NewStatesman?
Anyhow, I’m talking about Ljungqvist’s paper and Loehle. I don’t hear Mann jumping up and down on an internet blog claiming to have been vindicated by Ljungqvist. The fact that Loehle did just that is juvenile and unprofessional, and given that Ljungqvist did not refer to Loehle, that is misrepresenting Ljungqvist’s finding that his work agrees well with Mann and Moberg.
I agree with some of what you say, but McIntyre is wrong to say we simply do not know. The science does in fact not support that– please read the literature on EQS.
Paleo climates show that the climate system is sensitive to changes in internal and external forcings, and we are now tampering with the radiative forcing from GHGs and the planet has warmed asa result of that (not exclusively of corse, but the forcing is only going to increase with time because we have, artificially, hiked CO2 levels (not to mention other GHGs) to levels that the planet has not seen in an incredibly short time (geologically speaking). That is going to have a significant impact on the earth’s energy balance, and in fact the climate system has been in a net positive energy imbalance since the fifties (probably longer but Murphy et al. did not have data that went further back in time).
And as others in the know have noted, if the paleo records are not capturing the variance properly, then that points a higher equilibrium climate sensitivity than current research has determined using those data.
This is a no win for Loehle or McIntyre. I do not understand why people are so partisan that they cannot simply concluded that like a gracious, honorable gentleman would do and move on.
Scott, for a lay person, how about this, say you have 20 trees, and 3 of them show hockey sticks, 3 show the opposite, and 14 are flat. Is it OK to just select the 3 that show hockey sticks and average them together?
Where do they live? What are the site specifics for each tree? You have given insufficient information for one to answer the question.
A lot seems to rest on this statement by Jeff:
We have proxies that all are assumed to have different responses to temperature so each response should have a different multiplier
When it comes down to trees, there’s a rich store of knowledge of tree physiology which informs site selection. It’s not “assumption” at all.
MikeN, of course, believes that proxies are selected based on their corresponding to a hoped-for answer. This is simply untrue.
dhogaza claims: “When it comes down to trees, there’s a rich store of knowledge of tree physiology which informs site selection. It’s not “assumption” at all.
MikeN, of course, believes that proxies are selected based on their corresponding to a hoped-for answer. This is simply untrue.”
This claim seems to be largely untrue. Take the infamous bristlecone pines in MBH 1998. There is very little direct evidence that their growth depends solely on temperature. On the contrary Graybill and Idso thought their anomalous 20th century growth was caused by CO2 fertilisation and McIntyre has suggested that the strip bark forms show exceptional growth when damaged. The ring growth is anyway not correlated with local temperature at all. It is correlated with a principal component of the global temperature field, which is why Mann chose to use it…Similar problems affect the crucial subset of proxies with hockeystick shapes which are preferentially weighted by most of the multiproxy reconstructions. And then there is the divergence problem – the usual “solution” to which is to throw away parts of the data set which do not correlate. If there was adequate meta data about sites, detailed studies of how proxies responded to temperature etc I would take these studies seriously. As it is it just looks look automated cherry picking.
Dendro clearly have some issues, but fortunately there are many other proxies which, for some reason, McI et al. seem to ignore. You guys just keep rehashing the same old tired arguments, while everyone else has moved on.
As I have just posted elsewhere:
“You are clearly unaware of the multitude of other reconstructions which do not even use dendro and/or use different analysis methods (Thibodeau et al. 2010, Ljungqvist 2010, Kellerhals et al. 2010, Tierney et al. 2010)…and that is just a few from 2010 alone.
And guess what? Hockey Sticks all of them….”
And please note the “and/or different analysis methods” there before you point out that he used dendro records.
So McI and Jeff here know better than everyone else. Have you heard of the D-K effect MikeP?
The reconstruction methods I have seen all essentially take a set of proxies and construct a weighted average of the proxies ( a linear transformation based on scaling and weighting). simple versions throw away some proxies (i,e give zero weight to them). More complex procedures may give strictly non-zero weights to all the proxies. None of them make any sense unless there are good grounds for the weights, i.e. good grounds for thinking the proxies are indeed proxies for temperature and not just some sort of red-noise type series. Ex post correlation is not a good ground.
“Paleo climates show that the climate system is sensitive to changes in internal and external forcings, and we are now tampering with the radiative forcing from GHGs and the planet has warmed asa result of that (not exclusively of corse, but the forcing is only going to increase with time because we have, artificially, hiked CO2 levels (not to mention other GHGs) to levels that the planet has not seen in an incredibly short time (geologically speaking). That is going to have a significant impact on the earth’s energy balance, and in fact the climate system has been in a net positive energy imbalance since the fifties (probably longer but Murphy et al. did not have data that went further back in time).”
No. That’s the whole point of what Jeff is getting at. The results from most of the reconstructions reported as being climate signal are actually due to the methods being used to analyze the paleo data. The inappropriate methods used in many reconstructions are responsible for the belief that climate is sensitive. When analyzed using more appropriate statistical methods, the results are much different.
Start with your very first quoted statement above. How does one know that the climate system IS sensitive to internal and external forcings? How does one know that? From examination of past climate. How does one examine past climate? Paleo reconstructions. Many paleo reconstructions are of poor quality AND have used inappropriate methods for analyzing noisy data.
So, how about looking at it from another perspective: does it make sense that climate is sensitive to internal and external forcings?
In what other natural, large-scale chaotic system does one find it easy to create massive pertubations based on minor impacts (e.g., sensitivity)?
If the climate really and truly was sensitive to minor impacts, then one would expect massive and persistent climate changes from naturally occurring events (such as volcanoes, meteor strikes, etc). Yes, we know that temperatures can change temporarily as a result of volcano activity, but we know those effects do NOT impact overall climate for generations… which is exactly the opposite of what would be expected if climate was truly SENSITIVE to internal and external forcings. If climate were truly sensitive, then we wouldn’t be here… the climate would have spun out of control and resulted in runaway warming or runaway freezing that was persistent a long, long time ago.
I think you are missing JeffId’s perfectly valid point that selecting or weighting noisy proxies in order to produce a “fit” to the modern instrumental record will damp *any* low-frequency variance (i.e. will create variance loss) in the handle relative to the blade. It’s an unavoidable consequence of the fact of selection – the only question is the extent to which it impacts the reconstruction.
It has nothing to do with the *kind* of proxy used – dendro, borehole, ice core, lake sediment, glacial extent, ice break-up, sea level, or whatever. What’s more, it only has to do with the methods of analysis to the extent that they (a) avoid these selection/weighting procedures (e.g. by using a simple average) or (b) otherwise account for the loss of variance (as Jeff’s “reinflation” based on estimated variance loss would attempt to do).
That the problem repeatedly goes unaddressed (or waved off as if it doesn’t matter) does not make it less a problem.
Actually, I think I painted with too broad a brush in saying that it “repeatedly goes unaddressed…or waved off” – there have been some honest efforts to grapple with the problem (if I recall correctly Christiansen, 2010 approached it, though I think the fundamental problem actually went unaddressed).
It’s really a difficult problem to get around, because the extent to which any given proxy reflects temperature versus other “signals” (I’ve been upbraided by people with a better grasp of the relevant lingo than myself for using the term in this context, but still don’t quite understand why it isn’t appropriate) versus noise is not known a-priori. We really would like to select proxies that we have reason to believe are the good ones.
But there are problems. The primary ones seem very clear to me. They are (1) we can’t separate a proxy that shows good fit to our instrumental data because of chance from one that shows good fit because of temperature signal, (2) even if we could, we can’t assume that a proxy dominated by signal over the instrumental period was also dominated by signal pre-instrumentation and (3) even if we could assume that a proxy that is dominated by temperature signal recently always was, there would still be variance loss issues with extending the reconstruction back in time (due to addition and deletion of individual proxies).
That said, it’s easy to criticize the lack of a good solution, but coming up with one that produces reconstructions we can be confident in (meaning “for which the estimate is unbiased and the error in the estimate is itself accurately estimated”) is a lot more difficult. Still, that shouldn’t blind us to the fact that we can’t place much confidence in the current approaches.
As for quantifying that lack of confidence, Jeff’s estimates of the extent of variance loss seem to me to be the most thoughtfully constucted I’ve seen. No, the specifics don’t apply to every reconstruction, but why would we assume that other reconstructions that look a lot like Mann 07 – which we can be fairly certain has massive variance loss – are not similarly impacted?
Wow, look at the pile on going here. I must be onto something– well not me, I’m a mignon who is relaying the science on this issue as it stands right now, so Bruce, MikeN, MikeP, Jeff, Morgan you really you are arguing with the professionals in the field. Hands up which of you are trained and active researchers (i.e., publishing) in the paleo field please….
I do not want to have to keep repeating myself. None of this is new. The original subject is about Loehle claiming to be “vindicated” by the recent Ljungqvist paper. I and many others have explained, demonstrated even, why Loehle was wrong to do so. And Jeff is coy about speaking to comments made by Didactylos and others concerning the faults with Loehle’s work.
Let us forget the much aligned dendro chronologies for now. Regarding paleo reconstructions and equilibrium climate sensitivity. The arguments I’m reading here are contradictory. Some are saying that the pre-1880 variability is underestimated (b/c variance loss) by certain techniques (and that does seem to be a valid issue with some analysis techniques) and claim that Loehle reconstruction is the only one who has gotten it right. In contrast, others are claiming that EQS is low.
Now IF the amplitude of previous temperature variations is higher, that would point to higher climate sensitivity, but not hugely so (Bruce please your whole post is an example of reductio ad absurdum– I said higher, not sky high) than is being inferred from current paleo studies on the subject. At the very least, if that argument is true, then it certainly does not support low EQS. Besides, it has been explained ad nauseum why we don’t get runaway warming from a net positive feedback.
Please look at this Figure:
And this one
And then try and tell me that recent changes in temperature are not unusual, or that Mann08 and Moberg are way off the mark.
Anyhow, you can’t have it both ways. If you accept that the variance loss is a significant issue, that points to higher EQS. And at the same time that also means that one cannot claim that Ljungqvist’s paper “vindicates” Loehle for that reason, not to mention the fact that he never mentions Loehle.
Morgan, so you seem to be suggesting that ALL the paleo reconstructions, with the exception of those made by Loehle and McIntyre are wrong, or greatly underestimate the amplitude of previous temperature changes? By your logic it, at least if I am following your argument correctly, would mean that Thibodeau, Tierney, Kellerhals et al., and Tierney et al. are all wrong. Not to mention the dozens of other paleo reconstructions. Sorry, but that sounds very much like D-K effect to me and a convenient (but weak) excuse for dismissing some very inconvenient findings.
Folks, the planet is warming, that is because of elevated anthro GHGs forcing the system into a net energy imbalance. The recent warming is not some artifact of some possibly flawed analysis techniques applied to various proxy data, it is very real.
Anyhow, I have wasted way too much time on this and it is getting rather tiresome. This talk pretty much sums things up– I do not like the message and implications, but I’m not going to bury my head and/or obfuscate to make myself feel better or justify not taking action.
MapleLeaf, Mann didn’t claim vindication from Lundquist, but from Wahl Ammann, Briffa, and a number of other papers. Indeed, you refer to that in your last post.
You made the argument that it is not vindication for Loehle to point to a paper with a somewhat different result and different method. I point out that Mann when facing criticism did the same thing. Let each defend their own paper on the merits. In my opinion Loehle has done a better job of that than Mann.
>Where do they live? What are the site specifics for each tree? You have given insufficient information for one to answer the question.
Say they are all at one location. 20 trees, should you only select the 7 trees that show warming in the recent period, and then average those? Throw out the 7 that show no change and six that show cooling?
ML: So the climate is SENSITIVE to internal and external forcings, but not THAT sensitive? You can’t have it both ways. If climate really is sensitive to forcings, it’s sensitive to forcings… and one would expect wild swings in temperature due to very small pertubations. That isn’t what’s been observed.
And thanks, by I do not need to be lectured by you. However, I am more than happy to listen and learn from the likes of Alley….
You do not understand. Sensitivity to doubling CO2 (and we will very likely more than double CO2 with BAU) has a possible range of +1 C up to close to +6 C (values higher than +6 are highly unlikely)– that is, CS is constrained pretty well by observations (Knutti and Hegerl 2008). That does not mean that we cannot still refine CS higher or lower w.r.t the current best estimate, and still remain within the aforementioned range. For example, is it +3 C or +4 C, or +2 C?
I higher sensitivity would mean increasing it to more than +3 C, which is the current best estimate derived from multiple independent studies (which use model, paleo data or a combination of both, or even satellite MSU data (e..g, Annan and Hargreaves recent work)), but still remaining within the constraints of the system. That is what I am talking about.
So if you have issues, please go and argue with Annan et al. and try and convince them that they have it wrong.
“There are known limitations to the concept of forcing and feedback
that are important to keep in mind. The concept of radiative forcing
is of rather limited use for forcings with strongly varying vertical
or spatial distributions. In addition, the equilibrium response
depends on the type of forcing.”
“These effects are poorly understood and are
mostly ignored in simpler models that prescribe climate sensitivity.
They are likely to be particularly important when estimating climate
sensitivity directly from climate states very different from today’s
(for example palaeoclimate), for forcings other than CO2, and in
simple models in which climate sensitivity is a prescribed fixed
number and all radiative forcings are treated equally as a change
in the flux at the top of the atmosphere. Structural problems in
the models, for example in the representation of cloud feedback
processes or the physics of ocean mixing, in particular in cases
in which all models make similar simplifications, will also affect
results for climate sensitivity and are very difficult to quantify.”
If you restrict yourself to the last 400-500 years of their data, as you often see, you get a steadily rising temperature reconstruction (but not a real “hockey stick” as there is not shaft/blade corner. But I do find it curious that the data is commonly truncated there. I have looked for a good rationale for this truncation, but have not been able to find one.
I’m sure that the further you go back, the more heavily filtered the data is, and the wider any confidence intervals would be, but I haven’t been able to find anything that delineates 400-500 years BP as a cutoff. Can you find anything?
I share Jeff’s skepticism of boreholes in general. It looks like a hideously ill-conditioned linear algebra problem to me. Huang et al. try to get around this problem in the cited paper by averaging the results of thousands of boreholes together. Is that valid? I honestly don’t know. But their results over the last couple of millennia look a lot more like Lamb’s “traditional” history cited in the FAR (and Loehle’s reconstruction) than any of the hockey sticks.
Mapleleaf, the idea that only people working in paleoclimate studies can criticise teh statistical methods used in paleoclimate reconstructions just seems absurd to me. JeffID had documented his variance loss objections. If you can tell me why he is wrong (maths, statistical arguments etc) I will listen. But your constant appeals to authority are just unconvincing.
Much of the argument here is about statistics and properties of methods. There is nothing unique to paleoclimate about the arguments, other than the identity of the actual proxies. I am well enough trained in maths and statistics to follow the arguments and to make my own mind up about who is more convincing. One of the surprises for me has been the obvious statistical ignorance of some prominent names in the field. I offer in particular the Schmidt article in IJOC which fails to distinguish between autocorrelation in the dependent variables in a regression (not of itself a problem) and autocorrelation in the residuals of the equation, which is a problem. Residual autocorrelation is an important potential problem in my field, economics. And extensive work over the last 30 years or so suggests that residual autocorrelation usually results from misspecification. So the best solution is to respecify the equation, not to try and correct for autocorrelation by dividing the error term into a white noise bit and an autocorrelated extra bit.
Scott Mandia Says: October 1, 2010 at 20:54 “Why does the borehole data show a hockey stick?”
The borehole is not in a symmetric setting. As you go deeper (which is correlated with older temperatures) you move further away from the sunshine that warms the shallow circulating groundwater more than the deeper.
I note that different considerations apply for rock and ice boreholes. With rock, one is almost looking at an uncertainy factor where the energy that went into drilling the hole swamps the energy retained by the hole from past weather.
What is more, in rock, it is not uncommon for some rock types to be warmer or colder than those around them because they have different thermal conductivity towards the geothermal heat gradient.
There is another problem that almost all proxy methods share in the pre-instrumented period. It is resolution. One cannot reconstruct from a borehole representing conditions 200 years ago, the temperature resolution that you can get for last year, which might have had an abnormally hot month, or a very hot week. (Depending on when that abnormal month or week occurred, it might or might not have affected the proxy signal). Consequently, the presumed variance of the two periods is different. This causes a calibration error. One might say that pre-instrumental, Nature smoothed the data for many proxy methods. One should not compare statistics in a time series with different degrees of smoothing.
Sigh, your guess would be wrong. It was late, and as I volunteered, I was exhausted, so pardon me for not immediately recognizing the text. And I really was not in the mood to validate the source at that late hour.
Of course I have read KH08, some time ago as it happens, it was published in 2008 you know ;)
Anyways, the text that was cut ands pasted is from the beginning of the section titled “Limitations and ways forward”. Gosh, scientists (i.e., KH08) recognizing uncertainties and limitations– I thought that is what “skeptics” wanted? And my point was is that scientists have come up with some ingenious ways of mitigating/addressing some of the limitations identified in the cut and pasted text.
Anyhow, please show me where in KH08 they talk about a range of CS between -6 and +6? Actually show us anywhere in the reputable literature where they talk about a CS of -6 C for doubling CO2. Suggesting that range for CS indicates that you are unfamiliar with the science and have not looked at KH08’s Figures. And if that were not bad enough, you suggest “splitting the difference”, in case you had not noticed the PDFs for CS are skewed towards higher values, with a sharp drop off below +2 C (see their Fig. 3). See also Annan and Hargreaves (2009) .
I am not sure what point you were trying to make concerning the science and CS that is already not known? Or were you just trying to score cheap points?
October 2, 2010 at 05:41
“that is, CS is constrained pretty well by observations (Knutti and Hegerl 2008). That does not mean that we cannot still refine CS higher or lower w.r.t the current best estimate.”
“The well-constrained lower limit of climate sensitivity and the transient
rate of warming already provide useful information for policy makers. But the upper limit of climate sensitivity will be more difficult to quantify.”
I’m hoping that there are no nasty surprises on the high side, fortunately the likelihood of that are extremely low according to Annan and Hargreaves.
If you did not try to put out so many fires in a single evening, you might not be open to the cheap shots ;) Also, a single pot of coffee might help. Two makes you irritable.
Anyhow, -6/+6 is just reasonable distribution numbers for an engineer type like myself (and being anomaly centered). Actually, if you re-read KH08, the “Expert Elicitation” has a stated range of CS is 10C (fig. 3), and that is the experts opinion (dishonest in the distribution, for shame). Throw in a parameterized model, and the sky is the limit.
I’m familiar with the newer papers, where he scales back both the number of proxies and the time period of study by over an order of magnitude. I did a quick review of them today, and I can’t find any repudiation of earlier work. (There’s the same “the further back we go, the less confidence we have.”)
It’s very curious. It’s tough to see the point of this later work, if it doesn’t either build on or take down the earlier work. Do you know of any work, by Huang or others, that shows that 500 years is the boundary of what this technique can reasonably demonstrate?
“You are a professor by your link so you should be able to see the problem with correlation based sorting of noisy data. What do you think? Am I just lying or my computer has a bad math processor or is there some other magic trick I’m pulling? Maybe big oil is paying me? Or I’ve successfully tricked thousands of technical readers by hypnosis through my amazing command of punctuation. :)”
thanks for that light bulb, And for your other comment on sorting singal+noise, that made things very clear. So, here is the thing I don’t get. When Osborn complained to Mann that Mann’s CIs were way too narrow, nobody contemplates blowing him up in video, but when the likes of you or me suggest that the certainty is paleo is overstated, well hit the red button. and it doesnt matter because wegman plagarized something. Its the first time I’ve every seen plagarism change a mathematical fact. But you heard it first from me. Wegman was bad, therefore there is no variance loss. That’s hard for non math types to grasp.
October 2, 2010 at 12:27
Mapleleaf, the idea that only people working in paleoclimate studies can criticise teh statistical methods used in paleoclimate reconstructions just seems absurd to me. JeffID had documented his variance loss objections. If you can tell me why he is wrong (maths, statistical arguments etc) I will listen. But your constant appeals to authority are just unconvincing.
Yes, the tactic get’s a little old especially for people who have degrees in statistics and math or have worked with statistics and math. Jeff has put his code out there and makes a cogent argument. The EFFECTIVE way to respond is to take that analysis apart and post code in response. The ineffective ways of responding include:
1. changing the topic
2. changing the target ( what about HIM!)
3. appealing to authority, when your audience has demonstrated that they
rely on replication rather than genuflection
4. linking to something off topic.
5. hand waving
6. name calling.
7. motive questioning
So basically I look at it like this. I believe in AGW. All the evidence I’ve seen and all the things I’ve look at down to the bits, tells me the basic science is
solid. When A skeptic tries to challenge it, I’m almost certain they are wrong. they have not risen to the challenge of showing the errors in the basic science. On the other hand, I’m equally forced to accept JeffIds conclusions. Clear solid work. It runs on my system. His results check. No math errors, no chartmanship.
More generally ( to the rest of those reading)
Oh, Looking at the matter I’m not convinced that Craig L is “vindicated” I’ll stipulate that he is not. Now, to the question of deflated variance. That’s a simple impersonal math problem. has nuttin to do with climate science, has to do with methods. Jeff’s had his say, I’ll take silence as consent with his position. I’ll take “gainsaying” ( jeff you are wrong) as an admission of your own inability to demonstrate the basis of your belief. So, for me its pretty easy. I have a rational procedure for coming to conclusions. If you post your code and data on the question at hand, then I can fairly and completely understand your argument. And when your position is verified, then I have no choice but to consent. If you are not willing to submit to those rules of conflict resolution, then we can proceed to call each other names because if it aint the real data and the real code its just words on the page.
I can only assume that you post above was directed at me. Are really you accusing me of all those points 1-7, or were those general observations? Anyhow, if the former, odd that you failed to comment on Jeff making some of those very mistakes here and elsewhere.
Anyways, I do not need to be lectured by you thanks. And you clearly have not been following this thread carefully enough. The fact that I keep needing to repeat myself is evidence of that.
One of the many reasons the Wegman report is such a mess (and MW2010), as you too claim, is because the authors had no understanding or familiarity of the data– that is critical aspect of analysing the data appropriately. You’ll argue that that is not true, but my experience has shown that to be a very real problem when asking stats people to analyze or check data for me, and I know of others who have run into the same problem.
Also, please carefully look at the Skeptical Science plots that I posted above, as well as those posted by Zeke. The traces from the various reconstructions are relatively close– and that is a very important observation. If Loehle’s reconstruction does not suffer from significant variance loss as people claim (ignoring the other issues with Loehle’s paper for now), then the alleged 40-60% variance loss in the pre-calibration period present in other reconstructions does not appear to have a huge impact on the final results as shown by those graphics.So let us not make mountains out of molehills here like McIntyre tends to do.
Additionally, one cannot claim the paleo reconstructions (all except the flawed Loehle paper apparently) suffer from significant variance loss and in the next breath be of the belief that equilibrium climate sensitivity is low.
And this predictable red herring about me deferring to authority. Of course I am citing the experts in the field. If I were building an aircraft, then I would be citing (and consulting with) Jeff and his colleagues. Odd how my colleagues and I tend to look to others’ expertise to place our experience and knowledge in context– it keeps us grounded. Those authors have done the work, made the effort to write it up and go through the hassle of peer-review, and then to had it critiqued by their peers (and others) once in print.
Every single person who writes a journal paper, by your logic, defers to authority. The truth is that in research one is required to acknowledge and consider work done in the field by other experts, and then show how your work build on that.
One could argue that Jeff is appealing to his own perceived authority, or that Loehle is appealing to authority b/c he says that his work has been vindicated by a profession in the filed, namely Ljunqvist.
I am all for scientists and paleo people working closely with statisticians, not casting stones and nit-piking from afar. I agree with Oxburgh et al. that certain groups within the climate community needs to work more closely with scientists . But what I have seen thus far is people like McIntyre mostly throwing stones, attacking, grossly exaggerating the implications of flaws and engaging in innuendo, and as a result he has not making a constructive contribution to the science (you’ll probably deny that, but I think the public record speaks clearly for itself there).
Anyhow, if Jeff wants to conduct some great citizen science and publish his own paleo reconstruction (i.e., not just writing a paper saying X was wrong) in a journal which is peer-reviewed and accessible to the paleo community (not some obscure stats journal) and compare his reconstruction with Moberg and Mann et al., then I am all for that. Please, do go ahead.
Now on that positive note I am done talking about this particular matter with you guys. Read into that whatever you will.
> I believe in AGW. All the evidence I’ve seen and all the things I’ve look at down to the bits, tells me the basic science is solid. When A skeptic tries to challenge it, I’m almost certain they are wrong.
Must we presume that Steven Mosher is almost certain that Jeff Id is wrong?
Has Steven Mosher taken Jeff Id’s analysis apart and post code in response, and if not, when, if that is the only way to answer properly to a skeptic?
If Steven Mosher does not feel like he must answer to Jeff Id, why would others feel the moral imperative to do so?
Mapleleaf, you are it it again. Your criticisms are general rather than specific. You simply do not engage on clear enough issues to enable a serious conversation to take place. Of course you need to understand the data. As I understand it many of the reconstructions in palaeoclimatology rely for their hockey stick shape on a small number of proxies which prima facie look like weak evidence. For example the Graybill and Idso bristlecones, the Tiljander lake varves, the Yamal data. We would need to discuss how these proxies were chosen , why we think they pick up temperature (as well of course as whether the methods used to analyse them give them inappropriately high weight). Peer review, or place of publication, is largely a distraction from the real issues. Mendel was not wrong because his research was only published in an obscure botanical journal. Jeffid and McIntyre have laid out their criticisms perfectly clearly in a variety of places as well as having made their data and code available. The arguments stand or fall on their own merits. Schmidt IJOC was wrong even though it passed peer review (and for once we have the chance to see one of the peer reviewer’s comments, from Phil Jones, in the climategate emails, where he fails to pick up either of the two major problems in the article – failing to distinguish autocorrelation in the dependent variable from autocorrelation in regression residuals and failing to notice that using model output instead of observations gave even more different results for the socio-economic variables). If you want to discuss let’s discuss specifics and arguments.
I would be mistaken if an only if Mosher’s claim that AGW science is solid is compatible with this position:
> The sea ice, won’t melt, Antarctica land ice is in no danger of melting whatsoever, we couldn’t flood the Maldives from CO2 if we tried, acidification data is bogus, sheep aren’t shrinking, fish aren’t shrinking, hurricanes aren’t increasing, droughts aren’t happening, not one single disaster paper I’ve read is true in any way whatsoever and whole sections of the IPCC report are therefore bogus – including economic impact sections. If we created enough warming to change the climate, we might produce some flooding (from rain) or drought but nothing else of consequence and I’ve seen no evidence that we are producing any measurable warming whatsoever outside of models, which are nothing but reasoned guesses by people with a bias. The bias is created in the (potentially correct) assumptions of aerosols and water vapor feedback.
This point I am making is a simple point of logic. Either Mosher’s point about the AGW science is so minimal as to coincide with yours, in which case you both agree, or Mosher’s point does not coincide with yours.
I asked a question. That question stands.
The second point is about the necessity to refute the claims you make on the basis of your number crunching. More precisely, about the necessity to refute your claims HERE, in this very place on the Intertubes, or elsewhere in the blogosphere, if that really were a sphere. It would be wrong to conclude that questioning the necessity of doing so implies that your arguments, assumingly the ones you describe as being “careful,” should be ignored.
I am sure you can think about reasons to question number crunching. Speaking of which, have you ever wandered around Science of Doom? That seems to me to be the place for numerical bullying.
The only thing I would change about the quote above is
I’ve seen no CONVINCING evidence that we are producing any measurable warming whatsoever outside of models, which are nothing but reasoned guesses by people with a bias.
It’s a nuanced opinion I have actually. I’ve still not seen a convincing disaster paper, I’m still convinced the Antarctic won’t melt, the level of the Maldeves is determined by natural processes that track with the ocean.
All that and I am convinced that AGW is a real effect, but what part is natural vs manmade seems unproven to me. I would even concede that Bart’s opinion that it is actually worse than 100% of the warming is caused by man is a real possibility. I really don’t know yet and I ‘ve done a lot of reading.
You are very good at arguing strawmen and baiting– unfortunately, that does not facilitate meaningful discussion. I acknowledged that some climate scientists should work more closely with statisticians. Yet in your reply you then insist on again talking about the Schmidt paper and Jones not understanding statistics.
You keep referring to Jeff’s blog science also poses a problem for the AR5 folks, should they cite grey literature such as Jeff’s blog or not? Ironically, they have come under fire from citing grey literature before…..Anyhow I am not digressing into a debate about the pros and cons of peer-review.
I (and others) have been pointing out some issues with the logic presented by skeptics here and have also made a couple concessions along the way (e.g., I am willing to accept that there is variance loss in the pre-calibration period, and that climate scientists should work more closely with statisticians). And I have discussed some specifics with citations and links– how close the reconstructions are, what the implications are for CS for greater amplitudes in temperature variations in the paleo record, the fact that Loehle should not be using Ljungqvist to “vindicate” his work, for example.
Sorry, but I really am done arguing with disingenuous people.
Some food for thought while we continue to bicker over the nuances:
I don’t see JeffId as a skeptic, our views on the core science are very much in line with each other.
1. We both believe that GHGs warm the planet. You wont find either one of us spewing nonsense about trace gases, or violations of the 2nd law, or woods experiment, or natural variation explains it all.
2.We both see the real debate being over sensitivity. that means we will find fewer grounds of agreement about exact predictions. We generally are more skeptical of model results than most AGWers.
3. Future damages? agreement here depends upon agreement in #2. #2 isnt settled science, we can disagree. Take hurricanes for example.
4. The right response. without #2 and #3 settled, we lean toward “no regret” actions.
5. Paleo is immature
So, the antecedent ( if a skeptic says something) is not met. Jeff’s not a skeptic.
I can only assume that you post above was directed at me. Are really you accusing me of all those points 1-7, or were those general observations? Anyhow, if the former, odd that you failed to comment on Jeff making some of those very mistakes here and elsewhere.”
2. changing the target ( what about HIM!)
What makes you think I was talking about you. And if I was, then…
-1 for you.
And secondly if jeff or anyone engages in that behavior with me I generally call them out on it. So, what’s odd, is that you miss that characteristic of my commenting after all these years. THAT is odd. It is odd because I have made this similar comment many times in many places to many people on all sides of the debate. So, if you would like to change the topic to my behavior, that wont work either
“Also, please carefully look at the Skeptical Science plots that I posted above, as well as those posted by Zeke. The traces from the various reconstructions are relatively close– and that is a very important observation. If Loehle’s reconstruction does not suffer from significant variance loss as people claim (ignoring the other issues with Loehle’s paper for now), then the alleged 40-60% variance loss in the pre-calibration period present in other reconstructions does not appear to have a huge impact on the final results as shown by those graphics.So let us not make mountains out of molehills here like McIntyre tends to do.”
I am not discussing Loehle. I don’t think a comparison of results using various methods is dispositive here. Looking at jeff’s work with synthetic data, work that lets us understand the mathematical properties of a method is dispositive.
mountains and model hills have nothing to do with the technical question. The final answer may well be below the 40% variance loss ( which was for Mann), but I would not establish that by looking at spagetti. neither do you convince me by pointing at spaggetti. I have code from jeff. It works. The math is correct. And on your view I should weight pixels on the screen from zeke ( whom I respect, nice kid ) as heavily as I weight working code that I can tear apart? I have a different view of evidence. That view of evidence is not irrational, it is merely more rigorous than yours.
In most arguments with skeptics I always hate that point I reach when I have answered all their questions and they still wont change their minds. It reminds me that to have a consensus we have to agree on the ground rules of agreement. My ground rules are easy, open, and unchanging. show me the code, show me the data and if your claim holds up, I have no other choice than to accept it. Even if, and especially when, that involves me correcting my mistakes.
point me at words, point me at pixels and you are pointing me to an advertisement for your argument, not the argument itself. So, I remain open minded, willing to change my view. I’ve told you exactly what you have to do to change my view. Until then I weight the evidence in jeff’s favor.
“if you would like to change and topic and discuss my behavior, that wont work”
is not a strawman, technically speaking ( sorry, used to teach rhetoric). Its not an argument. Its a conditional statement of fact, a prediction. It says, “if you try this, that wont work” a strawman argument would be something entirely different. What I’m doing is telling you what will work as an argument with me and what wont work. This is a piece of information for you, not an argument. (You’ll do better if you avoid misusing terms)
That’s fine Maple, no one asked you to bite, Mikep and I were just noting that it is annoying ( on all sides ) that some technical questions that seem very straight forward always get avoided. Now, both sides do this. What about Mann? what about wegman? What about Jones, What about Goddard. blah blah blah.
And in all that, we just avoid going to the tough details. I’ll draw your attention to a recent post Jeff did on FDM. everybody was pontificating about the virtues and the vices of the method over on CA and jeff just went out and coded up a great test of all the methods. In the course of about 4 hours I went from being a proponent of the method, to a critic. I could see the math. I could run the code. None of the people looking at it could find a flaw. And the retired Stats professor gave him an A. So, here we had a debate that was spining around about personalities and arm waving, and jeff did some really straightforward work that just kinda shut everybody up.
“Anyhow, if Jeff wants to conduct some great citizen science and publish his own paleo reconstruction (i.e., not just writing a paper saying X was wrong) in a journal which is peer-reviewed and accessible to the paleo community (not some obscure stats journal) and compare his reconstruction with Moberg and Mann et al., then I am all for that. Please, do go ahead.”
This misses the mark on several grounds. Jeffs work that I refer to is chiefly a METHODS piece, more suitable for a stats journal. And in that venue his finding is so mundane and obvious ( since the loss of variance is so obvious) that it should not be published. 2=2 does not equal 5.
Next, if jeff did do a reconstruction, I’m fairly sure he would use standard proven methods which would give you floor to ceiling CIs ( or at least very much wider than those you see today ) This too is uninteresting to the climate science community. That, in a nutshell, is the dilemma. There is not a great deal interest in work that shows we are less certain than we think. The cause of that is open for speculation. That’s not a situation unique to climate science. just sayin.
So what can we logically conclude from this:
on one hand we have people who refuse to defend their methods. who refuse to vet their methods through statistical journals. They use these methods to create interesting results in climate science publications, where their is no requirement for reproducible results.
on the other hand, we have an individual who critiques their methods, publishes that critique in a manner than any competent person can replicate, but he refuses to use their suspect data and suspect methods to publish in the journals that accepted their suspect work based on suspect methods.
“There is not a great deal interest in work that shows we are less certain than we think.”
I’m not sure about that.
Convincingly showing common wisdom wrong is what every scientist strives for. What’s convincing for yourself may not be as convincing to others though (esp those who connected their name and fame to the common wisdom). But it became common wisdom for a reason: There probably are (or were) good reasons for it.
If you think too narrow confidence intervals are an example of such common wisdom which you can convincingly show wrong, I am sure that there will be a great deal of interest.
So no, I don’t think it misses the mark to suggest publishing.
> I don’t see JeffId as a skeptic, our views on the core science are very much in line with each other.
Here is another one:
> We generally are more skeptical of model results than most AGWers.
Now, since you used to teach rhetorics, you know that this is an equivocation.
In fact, it’s more than that, since this way of putting things renders almost everyone a skeptic, that is, everyone but the sorry guy who believes in everything.
And so the antecedent seems to stand, in some contexts.
Since you teached rhetorics, I believe you know that saying:
> [I]f you would like to change and topic and discuss my behavior, that wont work[.]
presupposes that this conterfactual is relevant, that is, that an opponent could do something like this. I believe that you do believe that your opponents do that sometimes, since later you say:
> So, here we had a debate that was spining around about personalities and arm waving, and jeff did some really straightforward work that just kinda shut everybody up.
So this could very well be considered as an argument, as technically speaking interpreted as a strawman, since you are in fact arm waving at hypothetical characters who attack the personalities of persons. To see that clearly, suppose you were talking about men who beat their wifes.
And to return to our subject, I also respect Jeff Id for his number crunching. I’ll simply note that the A in AGW stands for something about which Jeff’s last comment sounded really iffy and that you totally ignored.
My comment regarding the anthropogenic nature of warming is only to say, I’ve seen nothing which gives me the ability to say it is at least X or less than Y and that the ‘damage’ portion of the science reads more like voodo to me.
‘Roddy, I do not question how people have differing views on adaption and mitigation. I just do not understand how people can claim that there is no AGW or that AGW is a minor player.’
I can’t remember how we got here, but here goes:
a) Hardly anyone claims there is no AGW. Yes, I’m sure Monckton does, but who cares.
b) ‘people … claim ….AGW is a minor player’
That’s complicated – do you mean:
1 People think it won’t be as bad as you do, ie, for example, it will happen at the low end or even below the IPCC projections, the impacts will be not that bad, and adapted to anyway as we go, and so on, or
2 AGW is a minor player compared to all the other things we could be doing to improve man’s lot in a sustainable way, like hunger, genocide, literacy, freedom, malaria blah blah
I certainly have a hard time rejecting 2 too easily?
1 is really a question of the quantum of warming, then measuring the impacts. Am I alone is finding the work done on impacts often unconvincing? The only bloke who isn’t convinced the Maldives are going under?
Harry/Crackpot noted that the Dutch greenhouse industry uses high levels of CO2 in its greenhouses to increase plant growth, and that this is ‘proof’ that CO2 is the limiting factor for plant growth.
This, of course, completely neglects the fact that the Dutch greenhouse industry, like any greenhouse industry, also uses huge amounts of fertilisers and water to make sure *those* are not limiting factors. Plants cannot grow using CO2 alone, as any high school student should be able to explain to you.
You are quite correct Marco. Not to mention that they also use lights in some greenhouses that mimic the natural visible/light spectrum, and can regulate the temperature. Adding the CO2 is essentially like adding another micro nutrient to aide photosynthesis.
Higher CO2 levels also help plants using the C3 pathway more than they do plants which use the C4 pathway for photosynthesis. So the positive effect of CO2 enrichment is not equal for all plants.
So the example given is most certainly not “proof” that CO2 is the limiting factor for plant growth– plants did just fine when CO2 was at 280 ppmv, and have been shown to evolve to marked change sin CO2 levels by changing the number of stomata on their leaves.
Anyhow, a lot has been written about the impacts of elevated CO2 on plants, both the pros and cons, so I will not dwell on it here.
What you are saying is absolute nonsense. C3 and C4 plants do not have the ability to switch metabolism. It requires morphological adaptations, as for example the bundle sheath in Zea Mays to accomodate the alternative metabolism. Trust me, I know something about this.
The limiting enzyme in CO2 fixation, known as Rubisco, has a strange inefficiency at low CO2 concentrations as we have now. The properties of the enzyme suggest that it has evolved under much higher CO2 concentrations than we have today, which would explain why it shows improved performance at higher CO2 concentrations, concentrations which are folds higher than we currently have in the atmosphere. That is unusual in a biological system: they mostly operate within a narow range.
And obviously, water, light and (micro)nutrients have to be available as well in order not to limit the increased fixation of CO2.
But I guarantee that you can give plants the light, (micro)nutrients and water without the increased CO2, and get virtually nothing back in the sense of a measurable increase of production. CO2 is limiting.
Point, no way around that.
Do you think we Dutch are silly? We look after every penny, and we know when it pays to invest in expensive technology. That is why we have the most advanced cultivating systems around.
For water economy, visit Israel.
CO2 is limiting. No discussion possible. Science settled(?)
CO2 is not a micronutrient, it is the major nutrient, after water. But I remain with my thesis: the positive effects of the increase of CO2 to levels beyound 1200 ppm indicate that plants have been adopted to these levels long before our time. Which implies that CO2 levels have been much higher than they are now, and for very prolonged periods (billions of years), in a critical period for the evolution of the current biosphere.
You are arm waving Crackpot. Also, I never said using CO2 enhancement is a bad idea or silly– it clearly works in a controlled environment.
But do not necessarily expect the potential to be realized in the real world conditions were sunlight, temperature and moisture stress (not to mention disease) can offset and perhaps even negate benefits form higher CO2. If the soil moisture content is at or below the permanent wilting point, all the CO2 in the world is not going to help.
And I never said anything about plants switching metabolism….I said that they respond differently to elevated CO2.
I do stand corrected on one point though. According to the biology text in front of me, CO2 is classified as a macro nutrient, not a micro nutrient.
[Table 37.1 page 769 in “Biology” 6th Edition by Campbell and Reece]
For more information, please read the scientists response that CO2 is plant food argument:
being a plant biologist, I am sure you can not tell me anything that I did not know before. I can, as has been shown.
Chose your words carefully.
All plants share the C3 metabolism, only a limited number can use C4. C4 requires morphological adaptations. Even a more limited number can switch to CAM. And even less can go into hibernation, reviving when water becomes available.
And I see no reason why what would work in a greenhouse could not work in the open. Obviously, looking at the molecular properties of Rubisco, it did in the past. For a VERY long time.
Crackpot, if you are a plant biologist, you should know that in greenhouses all kinds of other nutrients are added to allow the plant to grow. If you don’t give the plants that, you’re at best getting more cellulose, which has ZERO nutritional value to humans.
Oh, and you would also know that photorespiration increases with increasing temperature, reducing carbon fixation. Want to reduce photorespiration? Think again: it’s a necessary process for nitrogen fixation. Ah, but I forgot, you believe the greenhouse effect does not exist.
You seem to be wanting to engage in a fight here b/c you are not listening to what people are saying. Did you read the link to the scientists’ refuting Monckton?
Yes, we forgot about CAM. Regardless, crops frown in hot and semi-arid climates (e.g., corn, millet, sorghum and sugar cane) use the C4 pathway and it has been demonstrated that C4 plants do not benefit form elevated CO2 as much as plants using the C3 pathway. And even then, the benefits for C3 crops are not terribly high (see Dr. Reich’s comment below).
Anyhow, it all boils down to this:
“And I see no reason why what would work in a greenhouse could not work in the open.”
Scientists in the know have explained why this is unlikely to happen, and that at best not all the benefits from higher CO2 will be realized in the real world conditions. A greenhouse is a controlled environment, growing crops (especially rain fed crops) is obviously not, there are several other limiting factors on crop health, seed quality etc. as has been noted before.
Dr. Peter Reich:
“The best evidence from state-of-the-art free-air carbon dioxide enrichment experiments is inconsistent with the notion of major sustained increases in crop yield in a world of doubled atmospheric CO2. Quantitative analyses
and syntheses of those experiments indicate that the direct effects of elevated CO2 will increase crop yields by 13% (on average for those with the C3 photosynthetic pathway, such as wheat, soybeans, rice) or 0% (on average for
those with the C4 photosynthetic pathway, such as corn, sugar cane, and sorghum); not the 40% Lord Moncton (sic) suggests. Moreover, these estimates ignore (1) indirect effects of CO2 as a greenhouse gas on future temperatures [edit i.e., , heat stress] precipitation, and their variability, and hence on future crop yields and (2) other consequences of fossil fuel burning such as rising ozone pollution that will reduce crop yields……”
I am listening to what people are saying. But to paraphrase George Orwell: some people are worth listening to, some are more than not worthy listening to.
I simply do not buy the crap that some people tell me is the truth. Especially when these people endeavour to go into my area of expertise, and tell me that I am wrong. And plant biology is a respected branch of science.
And what Dr. Reich thinks is as far as I am concerned complete bullsh*t. He is perfectly free to think like this.
Do you think that Dutch greenhouse owners invest millions of Euro’s in a CO2 sequestering project so they can supply their bell peppers with 1200ppm CO2 just without any proof?
These people are the most efficient business people you will ever meet. They calculate every cent, millicent even microcent.
Still they go for CO2 fertilisation at levels that you did not accept to be possible. They are, and they are well paid for.
“Do you think that Dutch greenhouse owners invest millions of Euro’s in a CO2 sequestering project so they can supply their bell peppers with 1200ppm CO2 just without any proof?”
You are still not listening. CO2 enrichment works in the controlled environment of a greenhouse, nobody I know of is disputing that. I have said that twice now. But greenhouses do not represent what is going on in the real world….I honestly can’t fathom why you cannot grasp that fundamental difference.
“And what Dr. Reich thinks is as far as I am concerned complete bullsh*t. He is perfectly free to think like this.”
Therein lies the rub, it has nothing to do with what he “thinks” or his “opinion”, but what observations made in real-world conditions have demonstrated.
Anyhow, continuing this discussion with you is clearly pointless. Good night.
You seem to have several things confused. The rate of photorespiration is dependent on many things, but the major factor seems to be the size of the plant. Furthermore, giving micro nutrients sufficiently for plant growth is a prerequisite. In any system. But you can not boost the production of a plant by supplying excess nutrients, if the nutrient is not limiting. CO2 does, with all plants tested. There is a difference in C3 vs C4 plants, but they have to do with the fact that CO2 fixation in C3 and C4 plants have different timings during a day. Light is the key.
Accept that when Dutch greenhouse owners have included CO2 fertilisation, that it pays.
a) try to dodge my point that photorespiration increases with higher temperatures (regardless of the basic level of photorespiration) by pointing to something else
b) completely ignore my point that greenhouses involve massive use of fertiliser in order for the plants to be able to grow (micronutrients? And you are a biologist by training? You better ask your money back, because they clearly failed to train you properly)
c) completely ignore MapleLeaf’s reference to actual field work in the area, and thus call the expert’s opinion bullshit.
Quite the consistent pattern with you: results don’t fit your preconceived opinion, hence you do not believe it.
Well I’ll give credit where credit is due, good job in replicating Ljungqvist.
Unfortunately, the spin and rhetoric throughout your post makes is obvious that you are pushing an agenda. Are you, for example, suggesting that Mann08 and Moberg05 were not mathematically honest, even though they used similar techniques to Ljungqvist and obtained very similar results? You also say something along the lines of “Now we have two reconstructions”. Really, only Loehle and Ljungqvist count, even though Ljungqvist is better agreement with Mann08 and Moberg05 than it is with Loehle? Not to mention the many other paleo reconstructions out there. Interesting…..you seem to be indulging in McIntyre’s antics of feeding the skeptics fodder– would it have pained you so much to mention even Moberg?
Earlier, “skeptics” were buoyed by Ljungqvist’s statement that his reconstruction suffered from variance loss, now you say it does not have much, but do not put a number on it (well, not that I could see). And if it does not have much variance loss (which is possible, not discounting that) how come then Ljungqvist’s reconstruction agrees so well with Mann08 and Moberg05? Obviously the various analysis techniques do not make a huge difference to the final result….someone it seems is making mountains out of molehills.
So, to summarize you conclude that Ljungqvist’s reconstruction is “mathematically honest” and does not suffer from much variance loss. If Ljungqvist is good enough to allegedly “vindicate” Loehle, then Ljungqvist’s (inconvenient) conclusion also holds true:
“Our temperature reconstruction agrees well with the reconstructions by Moberg et al. (2005) and Mann et al. (2008) with regard to the amplitude of the variability as well as the timing of warm and cold periods, except for the period c. AD 300–800, despite significant differences in both data coverage and methodology.”
Not only that, but the graphic you shows also indicates that currently N.H SATs over land are warmer than they were during the MWP (as have others). Good luck trying to convince Craig of that.
I do not have time to discuss this more with you, so I am cross-posting this at Tamino’s. And either you can go there and chat about it, or others can come here to chat about it.
I have not reviewed Moburg but Mann08 used different methods which should be rejected by anyone with half a math background. It’s difficult to mention a paper I haven’t read.
I believe Dr. Ljundqvist may be referring to the input series having variance loss built in them but haven’t had time to look at many myself.
“So, to summarize you conclude that Ljungqvist’s reconstruction is “mathematically honest” and does not suffer from much variance loss.”
His math is basically averaging, nothing wrong with that. He hasn’t personally created any of the variance loss problems other reconstructions exhibit and hasn’t weighted one particular series dramatically above the rest. Again though it’s likely that at least some of the series have variance loss built in. It’s still better than Mann’s work or the multivariate regressions of MW10 etc..
“Not only that, but the graphic you shows also indicates that currently N.H SATs over land are warmer than they were during the MWP (as have others). Good luck trying to convince Craig of that.”
My experience with Dr. Loehle is similar to that with Bart, they are both willing to go with reality ahead of agenda. If you paste a temp curve on either reconstruction, the MWP is less than today.
I of course cannot ‘chat’ at Tamino’s, nor would I want to.
ad a: increased CO2 levels will in fact suppress photorespiration by providing more CO2 to the competing O2. The effect of increased temperature will be negligeable to the effect of the increased CO2.
ad b: The use of nutrients in greenhouses is carefully monitored. They are expensive. There is a severe penalty on releasing fertiliser treated water into the open water. Your claim “massive use”is untrue. Dutch regulations state that all water leaving the nursery is as clean as the water into which it will be discharged. A lot of people have a good living taking and/or analysing water samples. On the next Hortifair next week go and visit it!), handheld detectors will be presented which are able to detect and quantify 14 different ions in the water systems used for fertilizing plants. This is the direction we are going into. I think you will need 10 years to come up with the current rate of development in horticultural technology in the Netherlands.
ad b: Yes, I am a trained biologist, at one of the best Universities available, with flying colours.
Yes I call that bullsh*t. You seem to be impressed. Be my guest. I am impressed by your “qualifications”.
“I of course cannot ‘chat’ at Tamino’s, nor would I want to.”
Why not? Are you “banned”? If not, what are you scared of? Or is it that you prefer to control the messaging?
“I have not reviewed Moburg but Mann08 used different methods which should be rejected by anyone with half a math background”
What you say about the methodology employed in Mann08 may or may not be true, but as your exercise has clearly demonstrated, the methodology used by Mann or Moberg or does not affect the outcome much when compared with Ljungqvist. The traces are very close together, with Mann and Moberg tracking closer to Ljungqvist than does Loehle.
Funny how that inconvenient fact is not highlighted by “honest” types like Steve and you, and instead used to suggest the HS is “broken” (well Steve may not have said so, he mostly leaves that rhetoric to his mignons) and make allegations of nefarious goings on. You and Steve and the clan really do need to stop your unhealthy obsession with Mann et al.
Anyhow, I am a stack of stuff to attend to here. Enjoy misinforming and manufacturing controversy.
PS: I’m not checking this thread again. See you over at Tamino’s place if you are confident enough to go there……
Why not? Are you “banned”? — Yup, for discussing global sea ice. Tamino is nuts IMHO.
“What you say about the methodology employed in Mann08 may or may not be true, but as your exercise has clearly demonstrated, the methodology used by Mann or Moberg or does not affect the outcome much when compared with Ljungqvist.”
Now that is interesting, I do agree that the results are similar. Where the difference occurs, is that Mann used raw proxies whereas Ljundqvist used a lot of completed studies. It means that the studies themselves can contain the regression based variance loss but Ljundqvist’s analysis is mathematically reasonable.
I have not proven the above, but I have spent enough time in paleo work to be fairly certain. More to come at tAV.
“Funny how that inconvenient fact is not highlighted by “honest” types like Steve and you”
Now that’s completely unfair, why do you think I came here, highlighted your three names and pointed out that the variance loss I had expected and discussed here, and Ljundqvist pointed out didn’t exist in his math. Note the title of the post I linked!! Do you think that was done to ‘trick’ you, or tell you what I actually found was different from what we discussed???
And regardless of your handwaving, the greenhouse industry is required to use massive amounts of fertilisers, or their attempt to increase growth rates using more CO2 has no effect. At best they’d be increasing cellulose levels, which isn’t much help to the nutritional value. That the Dutch government limits emissions from the greenhouses is not in contradiction to the use of massive amounts of fertiliser. Reports show that the Dutch use on average around 1500 kg/ha of nitrogen for the food production in greenhouses. That’s massive fertiliser use. Oh, and let’s not forget the highly optimised watering procedures used in greenhouses. None of that is even remotely available in the open. Hence the observation, contrary to your desired outcome, that increased CO2 in open air experiments is shown to hardly benefit C3, and C4 not at all.
It’s considered bad form to comment on the same website with different aliases. At least have the courtesy to say that you’re one and the same person.
When time allows I plan to look a bit at that variance stuff and what you posted on the recent hockeystick. I don’t agree with your political views, but I do think you’re honest when it comes to number crunching.
These people have investigated the properties of Rubisco in-vitro. I eat my socks if you are able to understand what they have found. (with some Tabasco/garlic to overcome the horrible smell/taste). They have a very clear conclusion. Please explain.
The 1500 kg/ha/year is a meaningless unit. It should be related to the amount of product that can be produced during this time, and compared to what a similar plot would yield without the added input. This is a science of its own, and I sincerely doubt your capabilities in this area.
We, in the Netherlands, have been working on this and related topics for over 100 years. You can not beat us. We are the best. Go to the Hortifair, and you will see. This is high tech/science.
And just using the natural capacity of plants.
Which can also happen in the open. Which happens in the open. Change the environment, and the composition of the vegetation adopts by changing the most abundant species, according to what factor is limiting. Eliminate the limiting factor and different species will show up.
It was merely from wanting to saving the people with the urge to call me a crackpot from the hassle to do so. But they will undoubtedly come up with new names. I go for nutcase, regarding the season :)).
Crackpot, why should I go to Hortifair when I have family working in the field? One notably a PhD from WUR on greenhouses. He’s explained me at depth the highly controlled environment they use in the greenhouses. Control of CO2, control of fertiliser (amounts and timing), control of watering (amounts and timing), all stuff that is much more difficult “out in the open”.
And you actually also point to another rather important factor: eliminate ‘the limiting factor’ and you get different species. As such, field experiments have shown that CO2 fertilisation resulted in more weeds. Stuff we can’t use for food.
Even with some of your family working at WUR, I would advise to go to the Hortifair, since the WUR has really little technically educated people who can realise the theoretical ideas into practical working solutions. I also have some relatives at WUR, I know about what is going on.
As for the limiting factor, it was just a general remark. Even for open field cultivation, technological advances are increasing yield and reducing the burden of over fertilisation, spraying with chemicals.
That is where trans and cis genetics come into play. We have identified several importants tagergets, such as the use of BT genes to make crops resitant to insects. We can mutate the Bt gene in-vitro much more rapidly than the insects can develop resistance. We know which active sites on the BT-protein are most effective, which domains determine the species to be targeted.
In a similar fashion, we are determining which factors govern plant morphological development. We can modify flowers at this moment, but also speed up the growth by extending the vegetative phase.
Crackpot, you should learn how to read: I have family working in greenhouses, he just also happens to have a PhD from WUR.
Regarding the paper: yes, I read it, I saw no obvious flaws in their experiments, and yes I agree with their conclusions. I see no need to reiterate them here, everyone can read the paper him/herself. You apparently don’t agree with them, so let’s see your paper showing them wrong.
Oh, and did you already rebut the Professsor in Horticulture saying the same stuff several others have tried to explain to you here?
I sincerely apologise for misreading you. You are right.
Regarding the paper: you can not, by any means, understand this paper unless you are a plant physiologist, which is up to current state of the art. From your previous remarks I have concluded that you can only discern a plant from its environment due to its green colour.
I really do not see why I should write a paper to rebut the Crafts-Brander paper. It is not my leage, the fact that I disagree with them is trivial. At least I can understand what they are publishing.
You obviously can not.
Which was the point I was trying to make.
Thanks for the confirmation.
I have been looking into your horticulture professor, but I failed to get his point. There is no proof in his publication that CO2 fertilisation does not work, he only states that it does not work.(with no proof, only 1 ref to a paper long overdue, Mitcell 1994)
Well I can guarantee you, it (CO2 fertilisation) will work, even in the open. It was developed in the open. The genetic make-up of the Rubisco enzyme tells that it was meant to operate in an atmosphere with factors more CO2. You can not change that by arm-waiving, red herrining. strawmanning. You are pinned.
Crackpot: you have already decided I do not know what the paper says (your first reply), and then you challenge me again to show that I do understand it. I have no interest in these games, I’d rather have a more intellectually stimulating discussion with people who are not armwaving about CO2 being the limiting factor, period. Regardless of Rubisco being able to handle much higher CO2 concentrations, fact remains that plants need much more than just CO2 to grow. Which is what David Wolfe also points out.
Alex: I have absolutely no intention to read stuff written by E.M. Smith, after all his incorrect ramblings about the surface stations. At the very least he disowned Watts & D’Aleo’s libelous conclusions based on his ‘work’, but that work still was wrong.
Alex, very good find: Pauling and Newton both went beyond the field they had expertise in, and failed miserably. So, why should I listen to E.M. Smith, who has no proven expertise in anything even remotely related to biology?
You have expertise in Biology? I am surprised to hear so. Never noticed that.
I gave you a seond chance, that is what we are used to in martial arts. Take the chance or leave it, we consider it as that you accept your defeat if you do not stand up to the second opportunity. Marco, I am not armwaving about the CO2 issue of Rubisco. You came up with a paper that you do not understand. Not my fault. Rather admit that you do not know anything about the physiology and molecular biology of photosynthesis. I do know. So my remarks can not be ignored or flagged as “armwaving”.
I also read the ChiefIO issue. Quite interesting comparison he made. He seems to know more about biology than self proclaimed biologist here on this site do.
Being a biologist, I know what is needed for a plant to grow. I also know very well that any limitation will decrease the growth of a plant, whatever limitation it is. And I know also that what we are trying to do in our greenhouses is to eliminate every limiting factor.
We have a dedicated system: we want to grow tomatoes or bell peppers and adjust all parameters to the optimal growth of the product, the longest lifetime of the planted material and the lowest input in the sense of money.
Of course this will not happen in the free environment. But the same principles rule the environment. We see that in cultivations, which are limited by CO2 such as poplar, asp, increased CO2 results in higher production of biomass. No other factor, fertilizer is needed.
We are growing plants with the current atmospheric CO2 concentrations at the lower end of their physiological range. CO2 doubling will not harm plant life on this planet, they would like to have even higher concentrations.
From simple skepticism, I strongly believe that the biological arguments regarding CO2 are extraordinarily misrepresented in climate science. However considering I’m an engineer with layman experience, you can imagine my own ignorance on the topic. A discussion of outdoor limitations of plant growth and the the effects positive and negative of CO2 and the requirements on other fertilizers, is much needed. It’s not just a single post but a series of discussions for the science interested that blogland could use. Basic info about CO2, plant varieties, any changes to bio-response as technical as you like. Four to eight paragraphs at a time is enough but more is fun too.
It’s not too big or small of an adventure, but it is worthwhile and far more rewarding than a few posts to one reader.
Of course I’m talking about educating a couple thousand readers (including me) to the basics of plant chemistry and how it is affected by CO2, and how it may or may not be taken advantage of in agriculture.
Crackpot, it took you loads of posts before you admitted other factors may also be limiting. That does not bode well for any further discussion, and I’m pretty sure anything I say about the paper will be followed by loads of strawmen, objections, etc. etc., which perhaps somewhere after a long discussion are toned down.
You, as a biologist, should know that C4 plants do not benefit from further CO2 per se. They only ‘benefit’ when you also increase drought stress or temperature. And several C3 plants, like cassava, make more toxins and/or less protein upon increasing CO2. Doesn’t really help us nor other fauna.
P.S.: read up on the FACE experiments: plenty of evidence of Rubisco limitations, and much lower yields in real-life than expected from highly controlled experiments (with the exception of trees).
The use of cassava to make more toxins could be very benificient. The toxin cassava produces, is used as a starting material for chemical conversion into a medicine to treat osteoporosis and the negative effects of the menopauze in aging women. So increasing temperatures would facilitate the extraction of this pro-drug, and give farmers a new incentive to use their barren lands, where cassava grows. It is a multi-million market for them. And maybe you are even now enjoying their positive effect, with a less barren wife;).
C4 plants need their rest. That means that they also need a dark period to unload the bundle sheath cells from the accumulated photosynthetic intermediates. When this requirement is met, they are ready for a new load of CO2.
I know the FACE, we are working on a genetically modified Rubisco. You wil hear about it soon.
Not sure what your last post is meant to say or insinuate. I’ll be direct and candid– you are the one being dishonest and moving the goal posts and exaggerating.
First, let let me walk you through our conversation today:
1) I say that AR5 probably will not be able to cite your work b/c it is from a blog.
2) You allege that the variance loss issue will be ignored in AR5, and you have also made allegations about Mann et al. ignoring the issue, or something to that effect. And you say there are scientists “on board” and that you are not concerned about your work not getting exposure.
3) I ask you to elaborate and to provide names.
4) You provide a link to the Ammann paper, supposedly as proof of the scientists who are on board and that this is becoming mainstream.
5) I then had a quick look at the paper. I posted a passage from the paper which indicates that this amplitude issue has long been discussed and much effort has been made to address it, and that Mann is in fact one of the many scientists who is “on board”. And here is another passage form that paper: “Lately, different strategies that reduce such amplitude loss have been explored (Juckes et al., 2007; Lee et al., 2008; Christiansen et al., 2009). They include one or a combination of approaches: the selection of a longer, more representative calibration period (Ammann and Wahl, 2007), partial (Mann et al., 2007a) or overall smoothing of the data (Crowley and Lowery, 2000; Mann and Jones, 2003; Hegerl et al., 2006; Lee et al., 2008), explicit inclusion of specific low-frequency proxy data (Moberg et al., 2005), application of a Kalman-Filter based reconstruction (Lee et al., 2008), variance-matching scaling (Jones et al., 1998; Esper et al., 2005; Juckes et al., 2007) as well as total-least-squares regression (TLS) (Allen and Stott, 2003; Hegerl et al., 2006, 2007; Mann et al., 2007a, 2008). TLS has received significant attention and new NH reconstructions that involve the use of this technique generally exhibit more pronounced amplitude (Hegerl et al., 2006, 2007; Mann et al., 2008; Riedwyl et al., 2009).”
Yes, the matter is clearly being ignored….not. Yet, you keep insisting in public forums that something nefarious is going on and/or some conspiracy is afoot– more than a little alarmist of you; but I understand that you have to keep feeding those skeptics fodder.
6) You then went off on a tangent about land mines, and your discussion tanks into arm waving.
It is absolutely ridiculous that I have to spell this all out for you. Linking to that paper was an own goal by you and did nothing to advance/support your preceding arguments made to me today.
Now, please look at this graph, tell us what the amplitudes between the MWP and LIA are for the various N. Hemi. SAT reconstructions. These are my estimates from the following figure:
Loehle: ~1.1 C
Moberg05: ~0.9 C
Ljungqvist (2010): ~0.9 C
Mann08: ~0.8 C
Now why would a global reconstruction (Loehle) have a larger amplitude that a regional ones? That does not make sense at all. Regional SAT anomalies are typically larger than global anomalies….it is also not clear by how much the amplitude is being overestimated by Loehle or underestimated (see we agree to some extent) by the other techniques. Either way, at the end of the day the differences are relatively small and if you were to show reasonable people the following figure they would wonder what the heck all the fuss is about:
You and Steve are making mountains out of molehills…and your behavior here and elsewhere on the web has underscored the very good reasons why Tamino et al. do not engage with disingenuous and dishonest hosts of certain internet blogs.
Keep on manufacturing doubt and controversy Jeff. Night night and don’t let your conscience bite.
If you follow Jeff on his blog and elsewhere, even here on the Wegman thread, you’ll see that there is a clear pattern of bad mouthing and trashing Mann et al. and their work, using pejorative rhetoric and making (generalized) insinuations of dishonesty in the climate community. It is really unfortunate in a way b/c it totally undermines Jeff’s credibility and reveals his true agenda. That said, I do not trash everything about him or what he does because I do not like his politicization of science, underhanded tactics and attacks on scientists. A case in point, I have even encouraged him to submit his work for peer review. He says that shows that I’m ‘tripping’, in fact I’m trying to be reasonable (but “spin” is their game and they do it well). In contrast, I find it difficult to believe that Jeff could bring himself to agree with Mann on any substantive paleo issue and broadcast it on the intertubes.
You said, and I quote:
“The use of cassava to make more toxins could be very benificient. The toxin cassava produces, is used as a starting material for chemical conversion into a medicine to treat osteoporosis and the negative effects of the menopauze in aging women.”
The toxin that cassava produces is linamarin, and yet you denied that linamarin is the compound in question. That’s a contradiction with the comment I cited.
““Me calling Jeff on that logic fail is not politics…” — I’d suggest you check the quotes you marshalled in your comment. Read carefully, they support my position more than your own.”
First, I never mocked Jeff for supporting Ljungqvist’s reconstruction, nor did I suggest that doing so was a sign of weakness. You are arguing straw men.
Second, I have read the quotes carefully, and I fail to see what your point is or how they support your position. Maybe we have a communication breakdown? Anyhow, I spelled out what transpired very clearly. Jeff is playing word games and spinning things, that is blindingly obvious to all but the most partisan.
Anyhow, I am not in the mood for arguing in circles and need to take care of stuff. Nice chatting with you.
I think “mock” was too strong a word for me to apply to the comment I was thinking of (Oct. 18 @ 22:37), where you said,
[JeffId], you are contradicting and tripping over yourself. Ljungqvist states that his work agrees well with that of Mann08 and Moberg05, and you have stated publicly that Ljungqvist is an “honest” reconstruction. In fact, you seem quite in awe of it. Now, in the quote above you are in effect stating/suggesting that Ljungqvist is equally flawed.
“The quote above” is
“Mann et al studies have been supported by subsequent equally flawed research”
I agree with Jeff as far as his quote, whether or not Ljunqvist deserves accolades. Mann08 is the example of “subsequent equally flawed research” that I am most familiar with. And as far as Ljunqvist 2010, a robust reconstruction needs both sound methodology and unbiased proxy data. I commented on that at the Air Vent
Anyway, nice chatting with you too. I am not trying to argue straw men, the Minimum Daily Allowance for that activity is easily met through perusing the comments of any A-List AGW blog, pro- or con.
OK, so you think that Ljunqvist is also flawed, and/or the proxies. I did not know that, and it makes your interpretation of things clearer.
Regardless, your stance on this is irrelevant to the present discussion– the important point here is that Jeff said he does think Ljunqvist is an honest-math reconstruction. And that flies in the face of his claim that the the only studies supporting the early Mann papers are ‘flawed’ studies. He cannot have it both ways.
As for you arguing star men in the example I cited, we’ll have to agree to disagree– I made my case for that. You were certainly attributing things to me that I did not say (as I noted), and you then used that to make an argument about politics.
I didn’t say that! I withhold judgment. The math looks solid, which is half the battle, and a huge improvement over Mann08. What I said was that the question of whether expert pre-selection of proxies is sufficiently unbiased, remains. I don’t know the answer.
> And that flies in the face of his claim that the the only studies supporting the early Mann papers are ‘flawed’ studies.
I bolded “only”, because that’s the key to “you’re trying to have it both ways!” Do you have a clear recollection of JeffId conveying that meaning? I’m not asking for you to go on a quote-mining expedition, anyway JeffId is a big boy and can speak for himself. But my sense is that, No, he hasn’t said as much. If (iff) he did, then I agree with you, he should correct or revise his stance.
Sorry, I did not read the thread you linked to–I do not go to AirVent for reasons stated elsewhere. Anyhow, point taken. You ahve got me thinking about what you consider to be the current gold standard in N. Hemisphere reconstructions and how does it compare with Ljunqvist, Moberg05 and Mann08?
“Do you have a clear recollection of JeffId conveying that meaning?”
I do not know what is so confusing here. I have provided the quotes for what Jeff said. Maybe it will help for you to read these posts:
Jeff has had ample opportunity to clarify his generalized statement/position and has failed to do so. The inconvenient truth for the “skeptics” is that Ljunqvist agrees with Mann08 and Moberg05, and none that I know of has (yet) managed to demonstrate that Ljunqvist is seriously flawed. And if they do, then that reflects poorly on Loehle, b/c of his juvenile post at WUWT.
I agree that Jeff is an adult, so I find it peculiar that you are electing to defend him so vehemently on this point.
Anyhow, AMac, have a nice day– I do have to go. I’d be very interested in reading about your answer to my question about the best paleo reconstruction out there right now and how it compares with other prominent reconstructions.
I think someone may have identified a huge error in climate models. The paper is being discussed at tAV but in the code for the CAM model, air pressure drop from condensation is apparently not included. I’m told that this is common and weather prediction models do the same thing.
I’m very new to models in general and wonder what you have to add.
“ML, I have repeatedly clarified my position to you”
No you have not, at least not with regards to your twisting of North’s words in your response to Eli Rabett. I honestly believe that you do not understand what you meant when you made this generalized statement: “Mann et al studies have been supported by subsequent equally flawed research”
From Ljungqvist: “Our temperature reconstruction agrees well with the reconstructions by Moberg et al. (2005) and Mann et al. (2008) with regard to the amplitude of the variability as well as the timing of warm and cold periods”
From JeffId, re Ljungqvist: “Another mathematically honest reconstruction”
To my knowledge, you do not think Ljungqvist is flawed, never mind “equally flawed”, but maybe your position on that has changed. If not, you join the dots….
Re: the best paleo reconstruction out there right now — I don’t know.
As an Earth Sciences major (many years ago) who keeps up a little bit, I was familiar with the general thrust of paleo, e.g. dO18 in ice cores and treerings. I only focused on the subject due to the reception I got from asking about the Tiljander data series at a mainstream pro-AGW Consensus website about a year ago, and getting responses that were often patronizing, and that also seemed wrong. In the event, both the snarky and the even-toned rejoinders were erroneous.
So Tiljander turned out to be a bad re-introduction, if one wished to cultivate confidence in the probity and correctness of the state-of-the-art peer-reviewed work in this area.
JeffId’s post on red-noise pseudoproxies strongly suggests that Ljundqvist’s methods don’t generate spurious trends, a big plus. At the Whiteboard, Ron Broberg just put up a nice post on an approach being worked on by RL Smith of UNC-Chapel Hill. That seems like another strong contender.
I’ve read two notable caveats for modeling, one by William Briggs in his columns, and the second by a mathematician with a Greek name… that I cannot recall (or locate his PDF’d presentation). Plus my own two concerns, about bias in proxy choice, and about understating the uncertainty estimates that should accompany paleo traces.
There is no parametrization of the pressure loss due to condensation in the cam climate model whatsoever. This will lead to large scale underestimation of moisture feedback as the pump from ground to upper atmosphere isn’t properly accounted for.
You are getting way too excited about this model issue Jeff…..although it appears that the issue is real, it is not nearly the big deal that you claim it to be and its existence comes as no revelation, they have known about it for some time. Speak to the experts like Trenberth et al. as to the impacts of this particular omission in the models. Anyhow, it seems that plans may be afoot to address the omission– any improvements are a good thing, right?
The paper that you link to has its share of problems– interesting how you uncritically accept their results. Again, speak to the real experts in the field and you’ll see that the hypothesis presented in the paper by Makareiva et al. quickly falls apart or is at the very least seriously flawed and not as significant as they claim.
You will of course not believe what I say, so again, I encourage you to speak to experts in the field….
ML, name one problem. I find none and I’ve spent literally days studying it – critically. Starting with the driving force behind hurricanes. Nick Stokes pointed out many potential issues, we found none in the end. Nick may still be looking right now.
I am hoping for some help, so far of all people Gavin Schmidt had the bravery to take a shot. He said it was left out.
Anyone with the wherewithal to take a crack at where we are going wrong should be interested.