In the last post we looked at the recent temperature reconstruction for the holocene, in particular the last 11,300 years, from Marcott et al. We noted that the changes over most of this very long time span were no bigger, but a lot slower, than the changes over the last century or so. That means trouble.
We also mentioned that the “uptick” at the end of their “main” (the “Standard 5×5”) reconstruction was much larger than in their RegEM reconstruction, and that they had expressed doubt about its robustness. The large uptick at the end (in 1940) is larger than indicated by the instrumental data — another reason to doubt its reality. Let me tell you my opinion why this difference exists. I could be mistaken, but this is what I think.
As I hinted earlier, it has to do with proxy drop-out over time. All 73 of their proxies cover the time span 5500 to 4500 BP (calendar years -3550 to -2550), but as time marches forward the number of proxies which still have data dwindles, especially toward the end of the reconstruction (1940) by which time only 18 proxies remain.
Suppose we were doing something similar for the years 1000 to 2000 AD, we had only 3 proxy data sets, and we aligned them during their period of common coverage, from 1000 to 1800 AD. One proxy ends in 1800, another in 1900, only one goes all the way to 2000. Let’s then compute their simple average (one of the methods used by Marcott et al.). We might get something like this (proxies as black lines, their average as red dots):
Note that the proxy which drops out in 1800 is the coolest of the three at that time. Hence when it stops, the average of what remains is artificially high after that time. This causes an “uptick” which is just an artifact of the averaging process.
The next dropout, in 1900, is again the cooler (at that time) of the two remaining proxies so it leads to another uptick which is just an artifact of the averaging process.
Now let’s look at the individual proxies from Marcott et al., aligned over the common period (5500 to 4500 BP), which go at least as far as the year 1800 (click the graph for a larger, clearer view):
In this graph, the black dots connected with lines are the individual proxies interpolated onto a 20-year time grid (as per the Marcott procedure). But when any of the proxies ends prior to 1940, it’s also circled. The circle is red if the proxy is “warm” when it ends and blue if the proxy is “cool” when it ends.
Below the individual proxies is their average, magnified and offset so that it doesn’t overlap the proxies themselves, but does show how the average changes over time.
Note that whenever “warm” proxies drop out it tends to decrease the average immediately after that, and when “cool” proxies drop out there’s an increase in the average immediately after that. For instance, three proxy series end in the year 1900 and two of them are on the “warm” side at that time. Therefore what remains is not so warm so the following average (for 1920) is a bit lower than its predecessor. Five proxy series end in the year 1920, and four of those are on the “cool” side at that time. Therefore the following average (for 1940) is notably higher than its predecessor. In fact, the sign of every change in the average after 1800 matches what would be expected according to whether more “cool” or “warm” proxies drop out just before the change.
That, I believe, is the reason for such a large “uptick” at the end of the Marcott et al. standard reconstruction. The dropout of “cooler” proxies introduces an artificial warming into the result. The RegEM reconstructions infill the missing data, so they don’t suffer the same fate and don’t show the large uptick. They do show an uptick — but not nearly so large.
From what I’ve seen, this problem is only important at the end of the reconstruction. The outstanding agreement between the “standard” and “RegEM” reconstructions before then rules out any profound effect of proxy drop-out on the reconstruction prior to about the 20th century.
Incidentally, there’s another way to ameliorate the problem. Nothing can solve it perfectly, because proxies do drop out. But one partial solution is to transform the proxy data sets to their differences. Then at each time step we compute the average difference. Finally, we sum the average differences to get the average temperature. I did this using the Marcott proxies, and compared it to the result using a straight arithmetic average:
The “big picture” is unchanged — temperature changes over the last 10,000 years have been no larger, and much slower, than what we witnessed in the 20th century (as reported by thermometers). But the reconstruction since 1740 is quite different:
Most of the changes in the standard average are due to proxy drop-out. The reconstruction by the differencing method still shows an unmistakeable uptick, but it’s no longer of unbelievable size. If we compare the reconstruction by differencing method to that using RegEM, we see that they’re similar:
In particular, their end-of-reconstruction upticks are rather similar:
The fact is that the uptick in temperature at the end of the reconstruction period is a real feature of the proxy data used in this study. While the size of that uptick is inflated in the “Standard 5×5” reconstruction, it’s still there and it’s still real. The only real mystery is why the hell anyone should be surprised or disturbed about this. After all, we already know what happened in the 20th century.
Incidentally, a great deal of bullshit has been spread around about the re-calibration of proxy ages by Marcott et al. The truth is, it makes very little difference to the essential result. I computed the reconstruction by the differencing method using the “published” (i.e., as reported in the original sources) proxy ages to compare that to the result using the recalibrated ages. Here’s the result:
The main difference is in the distant past, when the recalibrated ages indicate an earlier end to deglaciation than the originally published ages. That long in the past, I suspect that using the latest radiocarbon dating calibration is a distinct advantage. For the last few centuries, the recalibrated ages give only a slightly larger uptick than the originally published ages:
As for the very large uptick in Marcott et al.’s “standard 5×5” reconstruction, I quite agree it’s not correct but even Marcott et al. expressed doubt about it. More to the point, it is not the point of the Marcott reconstruction. The point is to define the extent and rapidity of changes throughout the holocene, in full knowledge that the most recent part is the least accurate because it has the fewest remaining proxies. For that purpose, all the reconstructions (including by the diferencing method) agree.
As for the entirety of the Marcott et al. reconstruction, two points cannot be overemphasized. First: the point is to reconstruct temperature change over the entire holocene, especially the past. This is hardly the final word on that subject, but it’s a good first step and a very strong indication that past changes didn’t happen as fast as what’s happening now. The exaggerated uptick in the “Standard 5×5” reconstruction is its least interesting feature, but it’s the most annoying to those who have an ideological reason to deny man-made global warming.
Second: we already know what happened in the 20th century.
Dave Burton, purveyor of foolishness and myths, submitted the following comment:
“Grant, I find it just plain bizarre that you wrote all this and never even mentioned Steve McIntyre, who first figured out what Marcott had done wrong, and whose excellent work is the whole reason you wrote this.”
For your information, Davy boy, McIntyre’s contribution to this was limited to his every effort to discredit the entire reconstruction, to discredit Marcott and his collaborators, and of course his usual knee-jerk spasms at the sight of anything remotely resembling a hockey stick, sprinkled literally with thinly veiled sneering.
Also for your information, the original version of this post mentioned McIntyre (and linked to his posts) extensively. But prior to posting I decided to remove that, since McIntyre had already fully explored the “low road.”
“That, I believe, is the reason for such a large “uptick” at the end of the Marcott et al. standard reconstruction. The dropout of “cooler” proxies introduces an artificial warming into the result. “
Yes, I agree. I think there are two main culprits, 54: OCE326-GGC30 and 58: Flarken Lake. These went through to 1940 with the original dating – both had cooled a lot since the anomaly base period. Re-dating set their end dates back in time, so they dropped out and helped make the spike.
Your quote sounds just like what McIntyre wrote: “Marcottian uptricks upticks arise because of proxy inconsistency: one (or two) proxies have different signs or quantities than the larger population, but continue one step longer.”
Not sure why Tamino thinks that’s wrong when he is pushing the same story.
Not sure why you think Tamino thinks that’s wrong.
What’s wrong, BM, is the ininsuation that there’s any wrongdoing, scientific fraud, etc at work here. Since the paper was clear that the 20th century paleo reconstruction was most likely not robust, no sane person would accuse the authors of fraud.
Kevin, Because Tamino has claimed that McIntyre got it wrong. His insinuation throughout this is that McIntyre did nothing origina, and that in fact everything was in the original paper. Yet when he reads McIntyre and elaborates on it himself it becomes original thought.
Which is it, Brian–McI ‘got it wrong,’ or ‘did nothing original?’ These two are not compatible.
From my point of view, Tamino’s focus has been on elucidating what Marcott does and doesn’t say, not on Mr. McIntyre’s comments–albeit the update above certainly doesn’t flatter McI. It’s Burton and other commenters–including Anthony Watts–have been pushing this particular sideshow. What Tamino has said about Mr. McIntyre is that his tone is consistently insulting and that he appears uninterested in positive contributions to knowledge–“he only wants to kill hockey sticks.”
That’s sure how it looks to me, for what that’s worth.
As to the appropriateness of Tamino’s work being termed “original”, I think his own words in the “For The Record” post say it best:
Quite self-evidently, all those things were indeed done (and Tamino’s analysis of Marcott has been extended further since those words were written.) McIntyre presumably could have done the same, but, as is his wont, preferred unsubstantiated sneering and innuendo.
Don’t know about you, but I prefer the light to the heat.
Thanks Tamino for going through the data with a fine-tooth comb! Stunning performance! As you said, the authors made perfectly clear what the limitations of their study are. That’s why they came to the exact same conclusions as you did. And that’s why people like McIntyre make themselves looking ever more foolish … as if this were still possible.
Seems pretty convincing.
Excellent post, Tamino.
What does it look like if you took the closest thermometer readings to those 18 proxies, reduced the time resolution, and then reweighted them to match the area represented by the proxies in the reconstruction? You could extract the closest grid point from the BEST and HadISST interpolated results and treat them as synthetic stations.
I like the way you start from a position of respect, and try and explain results that seems unreasonable without questioning the competence, motivation or integrity of the authors.
It is the sort of criticism any author would appreciate.
So, if we use the original dating of the proxies as done by the published studies, and not Marcott’s, is there still an uptick in the proxies of roughly the same order? I had the impression from other commenters that if you do this, the uptick vanishes totally.
Is McIntyre’s chart wrong? This one:
[Response: If you avoid the real problem:, false fluctuations caused by proxy dropout (say, by using the differencing method), then there’s an uptick no matter which set of proxy ages you use.
If, on the other hand, you switch from recalibrated to originally published ages, and push data which is beyond 1940 back in time or maybe extend the reconstruction beyond 1940 (when there aren’t nearly enough proxies no matter how you slice it), and limit only to alkenones, and do whatever else you need to get what you want … then you can flood the internet with innuendo and sneering.]
do you really have to be so rude to someone who doesnt agree whit what you write ? replying to someone with ” Davy Boy” doesnt make youre argument any stronger
[Response: I go by the pseudonym “Tamino.” Everybody knows my real name (I’ve been “outed” so many times it’s ridiculous) but that’s still my choice here and everybody knows that too. For him to address me as “Grant” — as though somehow we’re on a first-name basis — was, and is, astoundingly rude. So if you want to point the finger of “unnecessary rudeness” at anybody, point it where it belongs — at Dave Burton.]
And bert, Burton’s actions go well beyond simply not agreeing. He’s actively trying to convince coastal homeowners that the current trend in sea level rise is an illusion or, at best, a minor natural fluctuation. Follow the links tamino provided. Read. Then defend if you can.
Unless, of course, you’re already intimately aware of Dave Burton’s business.
If you want to know what I really think, read what I write. I have a web site: http://www.sealevel.info/
It’s not a blog, so you can’t leave comments, but there’s a lot of material there, including my contact info.
Tamino doesn’t want to admit that there’s been no detectable acceleration in the global average rate of sea-level rise in response to ~ 2/3 century of steadily increasing CO2 emissions and levels, but that’s what the data unambiguously shows. It’s all there on my web site.
BTW, Tamino, I didn’t mean to be rude by calling you by your first name. I had no idea you didn’t want to be called that.
[Response: There has indeed been detectable acceleration in the global average rate of sea level rise, as I showed here. But that is not the topic of this post. Those wishing to discuss the issue with Dave Burton can find his contact information on his website.]
Dave Burton, Other than for entertainment value, why would I be interested in anything you think or do?
“Burton Down the Hatches”
When “Battery” got battered
Burton’s Ship was shattered
It’s mainsail torn and tattered
As if it really mattered
Let me try again: “Spooon!”
As in: http://s259.photobucket.com/user/THEDecepticon/media/Cartoons/spoon.jpg.html
Since you titled the post “The Tick”, it seemed appropriate, but in hindsight I guess not everyone would get the reference…
[Response: OK, I get it. Pretty funny, but as you say not everyone will get it.]
> astoundingly rude
Doesn’t astound me anymore. Call it cynicism for all I care
I could not help think of Nigel Persaud (aka McIntyre) when I saw the title of the post “The Tick”. Seems to me that there are a few similarities between Persaud and the real thing ;)
To get back on topic, how many people here think that McIntyre will actually publish his own independent reconstruction?
As I’ve posted elsewhere, Marcott’s “perturbations” are essential to his final output. These consist of permutating each datum 1000x time-wise using that datum’s age-uncertainty as bounds. Therefore the whole graph is homegenized to a 300-year resolution, except for the final, 1940, bin. This is because Marcott sets the 1940 bin to zero age uncertainty. Therefore this bin is excluded from the homogenization — so the uptick is protected by Marcott’s processing rules. I made this point on McIntyre’s blog also, but to no avail.
ML: how many people here think that McIntyre will actually publish his own independent reconstruction?
BPL: McIntyre is not in the business of advancing our understanding of paleoclimatology. He is in the business of discrediting global warming. He has no incentive to do actual research, and very likely no interest in doing so.
I was being facetious ;) We are in agreement though.
What happens if you use the median of the proxy values at each stage rather than the mean?
How about if you find the median of the “differences” at each stage (rather than the mean) and then sum?
Don’t know whether it has any statistical justification but it seems like it might reduce the uptick at the end and also reduce the impact of extreme values on the reconstruction in general.
> Dave Burton … his business
Damn, I didn’t realize he was in the business of encouraging people to keep building on coastal North Carolina real estate. And, migawd, at the nc-20 site he identifies himself as ” Dave Burton IPCC AR5 WG1 Expert Reviewer”
Even those like me who were born in North Carolina can recognize hypocrisy when it’s taken to that extreme.
Misrepresentation, Denial, $PROFIT$.
Tamino you said “The “big picture” is unchanged — temperature changes over the last 10,000 years have been no larger, and much slower, than what we witnessed in the 20th century (as reported by thermometers).”
Yet in their FAQ Marcott said:
Q: Is the rate of global temperature rise over the last 100 years faster than at any time during the past 11,300 years?
A: Our study did not directly address this question because the paleotemperature records used in our study have a temporal resolution of ~120 years on average, which precludes us from examining variations in rates of change occurring within a century.
Can your claim be supported by the smoothed data in Marcott? It seems to me that they’re saying that you can’t make the exact claim that you are making.
I’d be happy to entertain such spikes if you want to propose a mechanism. I can’t think of one that is natural. You?
snarkrates, not sure why you use strawman here. The question is simple: Does the paper support Tamino’s claim? It seems from the Marcott FAQ that the resolution isn’t there to support the claim but maybe Tamino believes it does and can explain why it does statistically. It’s not a question of whether the tick is real or whether it’s due to man or natural variability. It’s simply a question of whether the proxy data has sufficient resolution to support Tamino’s claim.
We also cannot be sure that America existed before 1492, or the back side of the Moon before it was photographed in 1959 or so… and does the wind rustle the leaves of trees beyond earshot?
At dot earth, co-author Jeremy Shakun states the following
“Also for your information, the original version of this post mentioned McIntyre (and linked to his posts) extensively. But prior to posting I decided to remove that, since McIntyre had already fully explored the ‘low road.'”
Can you clarify something: Are you saying you used McIntyre’s ideas, but removed any citations attributing those ideas to him because he was taking the low road? Or are you saying something different? Thanks.
[Response: All I “learned” from McIntyre’s “analysis” is that Marcott et al. had re-calibrated proxy ages, that McIntyre blamed the uptick on the re-dating process, and that he was happy to hint at the possibility of deliberate deception on the part of the authors. The references to McIntyre in my original version were to his insulting tone regarding this work, but I finally decided it was better to ignore that and comment on the science. It now seems that on the “dot earth” blog he chose to accuse me of having “shamelessly plagiarized” his ideas on why the exaggerated uptick occurs in the Marcott et al. temperature reconstruction. He’s wrong.
I didn’t read all his posts about the paper, for two reasons: first, there are so many, and I find them so full of sneering and thinly veiled innuendo that they’re sickening; second, there’s really very little to be learned from him. In my opinion he’s just not interested in understanding the science, he only wants to kill hockey sticks.
I’m hardly ignorant of the effect of station dropout (in this case, proxy dropout) on averaging temperature data, I’ve known about it since long before Marcott et al. was even published. If Steve McIntyre wants to claim that he identified proxy dropout as the reason for the extreme recent temperature uptick in the Marcott paper before I did, fine. It wouldn’t be the first time two different people had the same idea. I congratulate him on his insight. As for his assuming that I got the idea from him and didn’t credit him, it’s no surprise that he would assume the worst possible motives in others.
My opinion: perhaps if Steve McIntyre had been more careful in explaining himself, more interested in communicating reality than in demeaning the results, and less indulgent of his own sneering, people might refer to him rather than me when mentioning the impact of proxy droupout, and the “dot earth” blog might be referring to his posts rather than mine as “illuminating.”
Also my opinion: if Steve McIntyre were really interested in the science rather than just killing hockey sticks, he might have applied the “differencing method” himself and discovered that the uptick is still there (but reduced in size) when the impact of proxy dropout is dealt with, whether one uses the re-calibrated ages or the original published ones.
But that would require him actually to do some science.
Notice that I not only identified (quite independently) the reason for the exaggerated uptick, I also implemented a method to overcome that problem? Notice how I showed the result and compared it to Marcott’s reconstructions? Notice how I computed the result using both the re-calibrated and the originally published proxy ages? Notice how I did so for the same latitude bands as Marcott, and compared those too? Notice how I even did an area-weighting of those latitudinal results? Science.
Notice also that I disputed the reality of the exaggerated uptick in the Marcott et al. reconstruction without once even hinting that the authors had manipulated the data for nefarious purposes?
As for the differencing method, I didn’t credit the inventor (I don’t even know who it is) although I didn’t come up with that one independently. Perhaps McIntyre will accuse me of having “shamelessly plagiarized” that as well.
“All I “learned” from McIntyre’s “analysis” is that Marcott et al. had re-calibrated proxy ages, that McIntyre blamed the uptick on the re-dating process, and that he was happy to hint at the possibility of deliberate deception on the part of the authors. ”
Then the proper thing to do when you first write the article is to credit him.
It’s pretty simple. It’s called scholarship.
[Response: That Marcott et al. re-calibrated proxy ages is in their paper — crediting him for that would be ludicrous. Blaming the uptick on the re-calibration is a blunder on McIntyre’s part. Not mentioning at the outset how happy he was to hint at malfeasance by others was an act of generosity. You have one hell of a perverse concept of “scholarship.” I guess we already knew that.
You know what’s really hilarious? I’ve been told that McIntyre did no fewer than 8 posts about this paper. Despite his verbosity nobody seems to have gotten the essential truth of the matter until I made it crystal clear — which shows that his central thesis was wrong, the re-calibration was not the problem. When I’m praised for being “insightful” it’s McIntyre who wants to claim credit for my ideas.]
“Then the proper thing to do when you first write the article is to credit him.”
Steven “Piltdown Mann” Mosher – he put it in quotes to make it clear that what he “learned” from McI is what he learned from the paper.
It’s all clear from the paper. Don’t need McI to read the paper for you, Well, maybe you did…
“Then the proper thing to do when you first write the article is to credit him.
It’s pretty simple. It’s called scholarship”
It’s in the paper. Anyone can read it.
Apparently Steven “Piltdown Mann” buys in to this:
“deliberate deception on the part of the authors”
I think Mosher’s down once on academic fraud on the part of the authors, and is very, very close to doubling down with his comment.
The only reason to highlight McI’s reading of the paper (which can be read by anyone) is to highlight McI’s conclusion (“scientific fraud”), and apparently Mosher’s back to his old “Piltdown Mann” position on climate science.
It’s pretty simple Tamino. You wrote that you had acknowledgements in your post. You wrote that you removed them. What you think of Steve Mcintyre is not the issue. What you think of me is not the issue. Your opinion of what constitutes good scholarship is shown by the fact that you originally included the cites. So, what I think about scholarship is not the issue. Your behavior shows that you understood the right thing to do. Include the cites. For some reason you changed your mind. We will never know what that is. But your own behavior shows that when you first wrote it, you did as you were trained.
[Response: I have repeatedly stated the truth — that the only “acknowledgements” were of his mistaken ideas and his insulting tone. For you to claim that these were owed to him for reasons of “scholarship” is either mind-boggling stupidity (which I doubt) or nothing more than a pathetic excuse to denigrate me in a dazzling display of your ethical shortcomings.
Perhaps you and others are so keen to discredit my insights because it is now obvious that McIntyre was so clueless about the Marcott paper. Cite that.]
I love the fact that the denialists are using the fact that tamino refrained from pointing out that SMcI is the clueless liar that he is, as a reason to beat him with. I understand that, in practice, it’s probably no fun being on the end of it, but it’s a fantastic insight into the dank, dark depths of the minds of people like Mosher – who’s mind was looking pretty dank and dark even before that.
It is only scholarship if one is citing a scholar rather than a polemicist. And in reality, I suspect he is not even particularly successful at that. All McI wants to do is provide a figleaf for the denialists who dismiss the science in its entirety. By devoting so much effort to one post all he has done is elevate its status. McI has never been about the science.
“CRU Tape Scholarship”
— by Horatio Algeranon
“The CRUtape Scholar”
That is me
From Climate Audit
“Also my opinion: if Steve McIntyre were really interested in the science rather than just killing hockey sticks, he might have applied the “differencing method” himself and discovered that the uptick is still there (but reduced in size) when the impact of proxy dropout is dealt with, whether one uses the re-calibrated ages or the original published ones.”
Communicate this to Revkin (assuming you believe he’s still reasonable, which honestly I doubt, IMO he teeters between lukewarmism and denialsism, which in my mind are identical). But if you try, and if he insists on McI’s “plagiarism” claim, we learn something.
The problem with both McIntyre’s and now Mosher’s claim is that they have the onus of proof backwards. That’s their great skill, accusing people BEFORE they investigate.
What a pair of munchkins.
Does anyone have any insight as to how the redating of proxies might have occurred?
RTFF (at realclimate.org) or RTFSM at sciencemag.org. Both explain it well, although the FAQ covers the reasoning in terms more understandable to people who do not deal with the mintutiae of C14 dating.
Thanks for the lengthy response. You wrote: “If Steve McIntyre wants to claim that he identified proxy dropout as the reason for the extreme recent temperature uptick in the Marcott paper before I did, fine. It wouldn’t be the first time two different people had the same idea. I congratulate him on his insight. As for his assuming that I got the idea from him and didn’t credit him, it’s no surprise that he would assume the worst possible motives in others.”
But you wrote that your original post indeed heavily cited to McIntyre. This presumably was for a reason. When people independently arrive at different conclusions by definition they haven’t been directly influenced by others with the same idea. That’s not to say you couldn’t have come up with the idea independently, but it looks highly dubious to observers not in your mind that you actually did. At the very least the deletion of attribution before posting smacks of impropriety, whether the impropriety is present or not.
[Response: What really smacks of impropriety is your implication that I engaged in some sort of impropriety. That’s seems like a common tactic from those who want to avoid the truth of the science.]
You know, he could have been linking to him to refute him… Ever think of that?
Of course, it doesn’t matter. Whoever came up with it first is just verifying the authors’ statement that “we don’t think it is robust”.
What McI, wte9, and others are trying to imply is that since the proxy dropouts led to the proxy reconstruction not being robust in recent years …
Then the instrumental record isn’t robust, either.
And if Tamino had plagiarized (which I don’t believe for a moment), this would make the instrumental record even less robust.
Crock of cow poop, that.
Oh, I am interested in truth. You all but admitted when you said you deleted the cites to McIntyre that your analysis was not truly independent as you’re now claiming. And to avoid acknowledging that you accuse me of some sort of impropriety for having the temerity to point out what seems fairly clear. The end of scientific truth hardly justifies such means.
[Response: I already told you that I didn’t get the idea that the uptick was due to proxy drop-out from McIntyre. That’s the truth, but you choose to call me a liar. I also told you that my cites were limited to the only thing I “learned” from what I read of McIntyre’s posts, that he blamed the uptick on redating and was liberal with hints of misconduct by the authors. That too is the truth but you won’t believe it.
Your behavior is despicable. Your claim to be interested in truth doesn’t ring true.]
“Oh, I am interested in truth.”
No, you’re not. The important point is in the paper itself, which points out the uptick is not robust.
The instrumental record is, of course.
If you were really interested in truth, you’d make clear the fact that the recent uptick’s not being robust is due to proxy dropout.
McI’s observation *strengthens* the reconstruction for earlier periods where more proxies are available. He *adds to* the robustness of the paper and its conclusion regarding modern temp trends unless …
You accept the insinuation that the modern instrumental record isn’t robust.
That’s McI’s point. The paper must be wrong because you can’t use the modern instrumental record to compare with paleo reconstructions. Because, in McI’s world, global warming isn’t happening.
It’s just ****-****** stupid.
This pissing contest over who discovered this totaliy insignificant point that the non-robust uptick is due to proxy drop-out is just a stupid diversion.
We have the instrumental record.
Did you use the truncated data sets in your reconstruction or did you add the original data back?
“The end of scientific truth hardly justifies such means.”
Actually, I disagree with this, in the sense that the bottom line is that it’s found in the paper, whoever read it first, and this makes McI’s claim of academic misconduct effing stupid.
I hope you’ve either e-mailed or possibly have even phone-called Revkin on this.
His blind acceptance of McI’s accusation is unacceptable. He should’ve contacted you first before accepting the claim as being true on its face.
Revkin’s pretty much a denialist these days, but holding his feet to the fire can’t hurt.
Yeah, I noticed that too. The way he gave time to the authors of this paper and then to the FAQ at RealClimate. But then he replied to Steve McIntyre with real concern. The guy doesn’t understand any more. You can’t do this job properly without 24/7 hate. Burn him bad.
I agree with you,Richard, Revkin has provided the forum for McIntyre to present his laughable accusation with good grace.
Thanks Nick but I have to warn you that I’m English. It was ironic.
Also, McI was perfectly happy with Wegman’s plagiarism of his false “Mannian stats always give positive hockey sticks” analysis, and Revkin seems blind to this.
There is a message in Marcott that I think many have missed. Marcott tells us almost nothing about how the past compares with today, because of the resolution problem. Marcott recognizes this in their FAQ. The probability function is specific to the resolution. Thus, you cannot infer the probability function for a high resolution series from a low resolution series, because you cannot infer a high resolution signal from a low resolution signal. The result is nonsense.
However, what Marcott does tell us is still very important and I hope the authors of Marcott et al will take the time to consider. The easiest way to explain is by analogy:
50 years ago astronomers searched extensively for planets around stars using lower resolution equipment. They found none and concluded that they were unlikely to find any at existing the resolution. However, some scientists and the press generalized this further to say there were unlikely to be planets around stars, because none had been found.
This is the argument that since we haven’t found 20th century equivalent spikes in low resolution paleo proxies, they are unlike to exist. However, this is a circular argument and it is why Marcott et al has gotten into trouble. It didn’t hold for planets and now we have evidence that it doesn’t hold for climate.
What astronomy found instead was that as we increased the resolution we found planets. Not just a few, but almost everywhere we looked. This is completely contrary to what the low resolution data told us and this example shows the problems with today’s thinking. You cannot use a low resolution series to infer anything about a high resolution series.
However, the reverse is not true. What Marcott is showing is that in the high resolution proxies there is a temperature spike. This is equivalent to looking at the first star with high resolution equipment and finding planets. To find a planet on the first star tells us you are likely to find planets around many stars.
Thus, what Marcott is telling us is that we should expect to find a 20th century type spike in many high resolution paleo series. Rather than being an anomaly, the 20th century spike should appear in many places as we improve the resolution of the paleo temperature series. This is the message of Marcott and it is an important message that the researchers need to consider.
Marcott et al: You have just looked at your first star with high resolution equipment and found a planet. Are you then to conclude that since none of the other stars show planets at low resolution, that there are no planets around them? That is nonsense. The only conclusion you can reasonably make is that as you increase the resolution of other paleo proxies, you are more likely to find spikes in them as well.
[Response: As has been pointed out by others there are higher resolution paleo proxies (some of which were part of the Marcott et al. set), but they don’t show the kind of change known in the 20th century. There are also much higher resolution reconstructions (for 2000 years rather than 11300) and they don’t show it either.
I also dispute your analogy. Large enough extrasolar planets could have been found much earlier through their gravitational effect or (if the line of sight were right) by eclipsing their host stars. The 20th century temperature uptick is so big, it would be very hard to hide even with low resolution proxies and dating uncertainty. That it would show no sign (none) in the Marcott reconstruction stretches the limits of plausibility. The idea that “the 20th century spike should appear in many places” strikes me as nonsense.]
Nancy, a low time resolution measurement does not support gremlins in the gaps, subresolution spikes and crashes without any physical basis. That’s low quality arm-waving on your part – there’s no evidence of such, multiple ice core data against them, and you have _zero_ evidential basis for postulating such spikes. And worse yet, no physics that could support such spikes with natural forcings.
By contrast, we have both the observations for and the physics supporting the current spike. Which will, at best, last thousands of years due to the concentration lifetime of CO2, and would (if a similar event _had_ occurred over that period) show up quite clearly in the Marcott Holocene data. So even if your short term gremlins existed, despite no supporting evidence, they would still be irrelevant to the current situation.
You are (IMO) making completely unsupportable claims. .
An analogy that is ingenious, but perverse.
Because we do have some insight, after all, about what is causing this particular spike? And it ain’t leprechauns.
WTF? First, I don’t know of anyone who seriously dismissed the possibility of extrasolar planets based on earlier null results. Second, as Tamino points out, the successful finds owed at least as much to the development of new techniques as to increased resolution. Third, the mechanisms by which planets form around stars are fairly well understood, and it would be surprising if they did not form. The same cannot be said of decadal scale temperature spikes on Earth. I know of no mechanism by which such spikes would occur without also affecting the centennial scale. The time constants of the system are just not compatible with such an interpretation.
“WTF? First, I don’t know of anyone who seriously dismissed the possibility of extrasolar planets based on earlier null results.”
Indeed. For the first time in a year (why, oh why?) I just went to WUWT and saw this statement straight up. I understand that this point of an analogy for an argument is entirely peripheral to the main game here, but I still don’t see why people should get a free pass to Make Stuff Up.
As far as I can tell this claim is *entirely* invented for convenience. I don’t believe that *any* significant number of astronomers have ever regarded the probability of extrasolar planets as being low. If there is any basis for the claim and it is provided I will happily apologise (for whatever that’s worth ;-) )
You know, I felt that the size of the uptick was due to the reduced number of recent proxies – and I could probably pull out some emails I sent stating so.
But – I didn’t investigate further, I didn’t quantify what effects reduced recent proxy count would have, I didn’t look at what alternative methods would show. Nor did McIntyre, whose _sole_ aim appears to be to denigrate any results that show our responsibility for climate change.
Tamino (my complements) did the lifting to check, to extend the science. That McIntyre complains (when he didn’t do the work) is sad, but based on past examples, hardly unexpected. Still – very sad on his part. It’s a shame McIntyre doesn’t actually perform science, primary research, rather than just attempting to spread doubt about others work…
Good lord, did I just read Steven Mosher attempting to lecture on ethics?
Has he finally, at long last, discovered there are such things as ethics? Surely, given his discovery is so new, he would take the time to learn more about them before he starts lecturing on the subject.
(Like newly-ex-smokers with emphysema telling healthy and fit non-smokers how to look after their body.)
The expression you’re looking for is ‘teaching granny to suck eggs’
He’s planning on suing Plato for plagiarism.
“Nor did McIntyre, whose _sole_ aim appears to be to denigrate any results that show our responsibility for climate change.”
Well, he probably also enjoys the attention…
— by Horatio Algeranon
Ticks are nasty critters
They bite and won’t let go
Can even give you jitters
From Lyme, as you may know
… or is it “Lyne”?
Tamino, I’ve just got to Thank You for some really insightful work. But in this ridiculous, politically polluted environment; you are forced to endure so much bulls..t. I don’t know how you put up with it, but I’m very grateful that you do. JP