Guest post by Frank Lansner
IPCC – How not to compare temperatures – if you seek the truth.
There are numerous issues discussed intensely when it comes to IPCC-illustrations of historic temperatures, here for example the illustration from IPCC Third Assessment Report:
Fig 1. Taken from IPCC TAR
In short we have heard of problems with 1) the Mann material, 2) the Briffa material, 3) The cherry picking done by IPCC to predominantly choose data supporting colder Medieval Warm Period, 4) Problems joining proxy data with temperature data mostly obtained from cities or airports etc, 5) Cutting proxy data of when it doesn’t fit temperatures from cities, 6) Creating and Using programs that induces global warming to the data and finally 7) reusing for example Mann and Briffa data endlessly (Moberg, Rutherford, Kaufmann, AR4 etcetcetc).
But, as I believe another banal error needs more attention:
8) Wrong compare.
Imagine for a moment that none of the above mentioned problems 1) – 7) has any impact and then lets just focus on the comparing itself. The data of the proxies suffer from 2 impacts:
A) “Technical averaging” – Impact of many series of date summarized.
Check out what happens when summarizing many datasets of temperatures, an example, the cooling episode 8200 years ago:
Fig 2.
Data taken from: http://wattsupwiththat.com/2009/04/11/making-holocene-spaghetti-sauce-by-proxy/
The white graph with the red squares are the resulting average graph: More temperature sets added together tends to flatten the average. Notice for example how many datasets certainly has a down peak between 8000 and 9000 years ago, but the timing for these datasets are slightly off, and so the down peak is almost gone.
So, to some degree we can expect multi proxies to yield an averaged overall graph.
B) “Direct averaging” – on top of the technical averaging, the data series are often averaged further to some degree using 30, 40 and 50 years Gaussian filters.
The result of averaging by A) and B) is, that the variability of the IPCC graphs on a decadal ´timescale are limited to just tenths of a degree K. But in reality, if there where any real temperature peaks on decadal time scale in the Medieval period, we will would not see these much in the typical data series IPCC shows.
Is this a problem?
Well, it certainly becomes a problem if these “super averaged” data are compared with data that is NOT quite as “super averaged”. And this faulty compare is just what IPCC do.
IPCC “Super averaged” data from proxies, are typically compared to “Observed” temperatures, that is, recent temperatures not at all submitted to the same degree of averaging.
Technical averaging – type A) – is to some degree not happening for observed temperatures, so how about type B), the direct averaging, filtering?
Well, For the IPCC graphis shown in fig 1 above, the IPCC text says: “All series were smoothed with a 40-year Hamming-weights lowpass filter, with boundary constraints imposed by padding the series with its mean values during the first and last 25 years.”
Explanation: If your data ends in year 2000, then the last genuine 40-year averaged/filtered point on the graph would be a point for 1980 with average of 1960-2000 near +0,2K anomaly. But the IPCC graph for observed temperatures ends at +0,43 K around year 2000. This more resembles the normal five years average of GISS year 2000 data:
Fig 3. Giss temperatures illustrated in year 2001.
So for IPCC/Mann etc. to get a year 2000 temperature as high as +0,43K, they must have used just normal 5 yr avg. A longer average period would yield lower temperature for the last year.
So, when IPCC wrote “with boundary constraints imposed by padding the series with its mean values during the first and last 25 years.” – they mean: “We don’t use 40 year average/filter in the last 25 years…!”
So the bottom line is: IPCC compares “super averaged” temperatures of the medieval period with a peak in modern temperatures only submitted to 5 years average.
IPCC basically compares a peak in temperatures in recent years with super averaged medieval data where peaks are more suppressed to conclude how much it is warmer today than in the MWP.
This is a problem !
From this illustration it appears that the peak after 1998 to some degree appears related to the big El Nino 1998 peak, here from appinsys:
Fig 4.
So, where there no El Nino peaks in the medieval period that could have affected the compare with recent temperatures? Yes, there where: http://co2science.org/articles/V12/N5/C2.php
So we have every reason to believe that there where also temperature peaks in the medieval period – peaks that just might resemble the recent El Nino Peak.
So no excuse for the IPCC to compare a modern temperature peak with medieval average temperatures.
This is banal, of course, and even IPCC must have been aware of this, one should think.
Here: An illustration where the single year 2004 for observed temperature data explicitly is used in comparison with the super averaged medieval temperature data.
Fig 5. (from here)
Cheers!
“mike roddy (08:39:54) :
[…]
It is unworthy of consideration”
Mike, is this you?
http://northwardho.blogspot.com/2008/09/polar-cities-go-hollywood-2112-hopes-to.html
Catastrophe movie 2112? Global warming? Like 2 Emmerich films in one? Who’s going to play the damsel-in-distress? Oh… wait… let me guess… Sandra Bullock?
So may i deduce that you have a vested financial interest in keeping the AGW scare going?
Do you think there would be some kind of peak on a reconstruction if it properly accounted for 1289 the way it putatively does for 1998?
http://www.newscientist.com/article/dn12098-freak-winter-is-europes-warmest-for-700-years.html
My First comment would be, that when a “message” fails to communicate a “meaning”, it could mean that the “writer” of the message is not fully conversant in the finer points of the “language” that was intended to be used.
BUT; A “message” can also fail to communicate a “meaning” if the “reader” of the message is not fully conversant in the finer points of the language that was intended to be used.
So I have no idea where I might fit in the competence level of the English language; specially the American version of it; but I thought I grasped the message of Frank’s essay with no apparent difficulties; so I am somewhat non-plussed by the observations of others.
Secondly; averaging is avery well understood mathematical process. You have a set of (n) numbers; you add all the numbers together, and then divide the sum by (n) and the result is the “average” or “mean” of that set of (n) numbers.
This is true regardless of (or irregardless, as the case may be) of any linkage or relationship between any subset of the (n) numbers.
The numbers can be the output of a random number generator, for (n) trials of that generator; or they could be totally linked, such as successive readings, at say 10 minute intervals of an ordinary thermometer sitting in a swimming pool full of water.
The mathematical process, is exactly the same in either case. In the first example of random numbers, the final result has exactly zero meaning or significance; other than it is the average of that set of numbers. In the second example, the final result, might be a better value for the temperature of that swimming pool of weater, than any single one of the individual readings was.
I don’t understand the point of computing the average of sets of numbers, that have no reason for the average to mean anything. It adds no information.
If the numbers are in fact the result of some linkage process, such as for example in the swimming pool temperature case, it could be that the value being measured actually happens to be time varying, over the course of the total data gathering cycle.
In which case, the true value might be expected to be different for each time epoch for which a value is recorded; so the sequence of numbers represents some sequence of events; such as a changing temperature due to some physical process that is happening.
In that case; averaging also adds no information; in fact it throws away information that was already there, and replaces it with a false number; which may never have been observed at any time in the process. The most we can say; as a result of a very fine argument in Galileo’s “Dialog on the Two World Systems”, is that there must be at least on point during the total interval where the variable had the exact value of that computed average.
Well the bottom line, is I understand the merit in averaging what are presumed to be a set of measurements of some observational value, in order to reduce random errors that crop up in measuring any real physical variable.
But I see no merit at all in averaging a set of values that are all different observations of a changing variable; those values being deliberately different because some physical process is changing the experimental conditions, and hence changing the observed value.
Those numbers are different becaue they are supposed to be different, and the average is not a valid substitute for any of them.
Tenuc (07:18:31) :
Give the guy a break JDN, Frank isn’t a native English speaker.
Didn’t realize. That makes sense. He *really* needs an editor. The “mistakes” are grammatical & spelling mistakes, not scientific so far as I can tell. I was writing that comment over breakfast, and, my comment wasn’t as fully qualified as I would normally make.
DirkH (07:38:07) :
You seem not to know what you are talking about here.
I got the general idea about windowing errors with a running average, but, this is a common problem. I’m not sure the IPCC is doing anything dishonest or wrong here. That’s why I said I didn’t get anything from the article and that it needs better examples of the mistake he is alleging. The argument should be made again with a better organization & a more pointed example of how this alleged error is skewing the IPCC reporting in a way which would be avoidable by other methods, if that is possible.
You folks are being too kind to the man. Given the gross data manipulation which has occurred to get to the hockey stick, this changing of the averaging window seems a second order effect. Most people commenting here seem convinced by this article that the IPCC’s averaging is a problem. Is this really on the same order of error as everything else we’ve heard about? If it is, then this article didn’t demonstrate the severity of the error.
“Questioning the basic expertise and integrity of those who develop these global temperature charts for international organizations is not credible, and is unsupported by actual scientific evidence.”
This is what they have come to. Just handover the trillions, put on this hairshirt, and don’t question “science”, because you are too stupid to understand why the linear algebra and statistics you learned in college was, in fact, correctly applied.
Lets apply a little logic to Mike Ruddy’s statement. By his own standards, can he know whether the science is right or not? No. So, what we have here is the opinion of a blog commenter that, because he can’t understand the issue, nobody else can either. A blog commenter who probably gets his science through a layer of press that is in no way peer reviewed.
I always said that McIntyre was like Martin Luther nailing his manifesto to the IPCC door, and authority loving toadies continue to insist that only they are qualified to interpret the scripture.
Another revolution happened at that time that was likely related. The printing press. A revolution kind of like the internet, which brought orders of magnitude more minds into the discussion of issues.
Face it Mark, the days of Phil Jones issuing Papal Bulls, or Fatwas, from East Anglia are over. The sooner you understand this, the better.
JDN (09:43:39),
So you explain: “The ‘mistakes are grammatical & spelling mistakes, not scientific so far as I can tell.'”
Then, you make the same accusation of scientific error that you originally made, again without specifying exactly where the “mistake” is.
FYI: McIntyre & McKittrick falsified Mann’s hokey stick chart to the point that the UN/IPCC is no longer able to use it.
And the IPCC loved Mann’s chart, using it numerous times until it was thoroughly debunked. It was the most alarming chart imaginable. And now it’s been debunked.
If Mann’s hokey stick hadn’t been debunked, the IPCC would still be using it in their assessment reports.
I wonder what would happen, or if it would be possible to calibrate historical proxies to events like 1289, or cold periods due to volcanism? The reason this cannot be done is political, I am betting, not scientific.
In paragraph 6, meant to say the second graphic.
“JDN (09:43:39) :
[…]
window seems a second order effect. Most people commenting here seem convinced by this article that the IPCC’s averaging is a problem. Is this really on the same order of error as everything else we’ve heard about? If it is, then this article didn’t demonstrate the severity of the error.”
It’s really got to do with fidelity, quality, error bars. You see, they are trying to filter a 0.6 deg C signal rise out of the temperature record of a planet that’s surface temperature varies in an interval of 130 deg C. So allright, we need averaging or filtering or we have no chance to see this diminuitive rise.
The entire AGW theory is built on the reliable detection of this minuscule signal. So the way you handle your data is deciding about whether your result has any meaning. We are talking about a signal to noise ratio of about 1:256 or 48 db here.
And that’s why i think this improper treatment of the temperature record is highly significant. It renders the IPCC’s result practically meaningless IMHO.
”
Don Easterbrook (07:48:29) :
When geologists first saw the Mann et al. curve, we all just laughed because of the solid geological evidence for the Medieval Warm Period and Little Age published in hundreds of papers for decades. Our conclusion was that either the trees that Mann and others used were not sensitive enough to record climate changes or else it was a total fraud. The Climategate emails showed us the answer to that question. Instead of endless arguing over the details of their bogus curves, it would make more sense to just go to the geologic evidence which shows beyond reasonable doubt the Mann et al. curves are worthless.
”
This comment i find very interesting indeed. I recently here on WUWT made an analysis of MWP temperature results. I compared results before and after IPCC changed opinion in 2001, and found a huge difference in results before and after 2001 when IPCC published the Mann graph:
http://wattsupwiththat.com/2010/03/10/when-the-ipcc-disappeared-the-medieval-warm-period/
Don Easterbrook, you here confirm that we had a consensus PRO a warmer MWP. If you can add any information on this issue I would be very interested.
The thing is, if IPCC in 2001 acted against the consensus back then, this is one of the strongest signals, that IPCC has an agenda that is not entirely scientific.
Is it possible to “prove” that we had a solid MWP-consensus until year 2000?
K.R. Frank Lansner
“DirkH (09:40:50) :
[…]
Catastrophe movie 2112? Global warming? Like 2 Emmerich films in one? Who’s going to play the damsel-in-distress? Oh… wait… let me guess… Sandra Bullock? ”
Oh, i’ve read it, Penelope Cruz. She’s hot, great if you can get her. But drop that Armageddon guy, that movie was lame. Try to get Mel Gibson involved, i think your script idea sounds pretty much like Mad Max 2, and that was a fun movie to watch.
Alan Bates (03:25:30) : “A trivial point, perhaps, but irritating to someone who believes in precision in science: ‘… the variability of the IPCC graphs on a decadal ´timescale are limited to just tenths of a degree K.’ Temperature is measured in Kelvin, not deg. Kelvin. You are correct when you use 2K or similar. Please, don’t give people an excuse to ignore the key point being made.”
Yes, beyond trivial, Alan. Scientists who can’t do actual science now play with nomenclature and symbolism, instead. Thus we have, of late, Pluto demoted from a planet to some other term. The Medieval Warm Period has been turned into the “Medieval Climate Anomaly.” The hoax formerly known as Global Warming has become the Climate Change canard.
Similarly, In ancient days of my youth, when Science and Journalism still existed, we had temperature measured in °K (or °C or °R or °F or °Whatnot). In postmodern times, the little degrees symbol (°) was dropped as too hard, too time-consuming for scientists to make, the latter no doubt being too busy contemplating their navels or doing creative statistics or counterfeiting data or making up new names for old concepts. Now we have, instead of 2°K, “2K,” which I invariably first read as 2000, since K has always stood for kilo or 1000. [I’ll skip allusions to potassium!] That little ° symbol was there for a reason. Science is dead, abandoned in favor of trivial word play and GCM mathematical self-molestation.
Mikkel (22:51:19) : “This post is written in good quality Danglish, which should not be difficult for native English speakers to understand. As native speaker of a world language, one must be able to decipher its use by non-native speakers. I have seen far worse examples in reports and blog entries linked-to from WUWT.”
Easily we used to such phrasing and construction get can.
Hi JDN
Are you a secret agent 🙂 ?
You write “Is this really on the same order of error as everything else we’ve heard about? If it is, then this article didn’t demonstrate the severity of the error.”
Look, i start the article out:
“In short we have heard of problems with 1) the Mann material, 2) the Briffa material, 3) The cherry picking done by IPCC to predominantly choose data supporting colder Medieval Warm Period, 4) Problems joining proxy data with temperature data mostly obtained from cities or airports etc, 5) Cutting proxy data of when it doesn’t fit temperatures from cities, 6) Creating and Using programs that induces global warming to the data and finally 7) reusing for example Mann and Briffa data endlessly (Moberg, Rutherford, Kaufmann, AR4 etcetcetc).
But, as I believe another banal error needs more attention:
8) Wrong compare.
”
So, my input here is just a little shake under the IPCC graphs that already are ruined. The interesting about this error is, that its so banal that its tells a lot about IPCC having an agenda. Using proper compare might reduce the recent peak compared with MWP temperature with 0,2K or so (very much depending on what you do!) so a correct compare could not itself totaly ruin the Mann graph message. But we see an error so banal that IPCC appears either incompetent or manipulating results. Can you follow me on this?
K.R. Frank Lansner
Turboblocke (03:43:15) :
“our infamous correspondent neglects to mention the benefits which range from £20.7 – 46.2 billion/year.”
I can’t find anything about that in the link you mention. As it leads to maybe a dozen other documents, maybe you could be more specific.
This comparison of highly smoothed data to lightly smoothed or unsmoothed data shows up in other places also.
Maybe this should be called MANN TRICK #2:
The Penn State press release on the Mann 2009 article on hurricanes, at http://www.essc.psu.edu/essc_web/research/Nature09.html , states
>”In 2005, there were a record 15 Atlantic hurricanes, including
>hurricane Katrina, which devastated the city of New Orleans in
>Louisiana. These peaks contrast with lulls in hurricane frequency
>the study identified before and after the 1000 AD peak, when 8 or 9
>hurricanes occurred each year.”
The data from around 1000 AD of 8 to 9 hurricanes each year is highly smoothed data that should actually be expressed at 80-90 per decade, or more perhaps even more appropriately as 800-900 per century.
A tipoff that the 8 or 9 per year estimates are bogus is that the standard deviation is only about 1 hurricane per year. The observed std deviation in hurricane counts is about 4 per year.
Charlie
I stand by my prior comments.
The notion that mathematicians (McIntyre) weathermen (Watts, Bastardi) or economists (Lomborg) understand data better than the climatologists who developed it makes no sense whatsoever. Developing temperature reconstructions requires a lot more than knowledge of algebra.
The hockey stick is not “broken”. It has been vindicated by NSF and any major scientific body that has looked into it. There are at least 20 data sets that show the same trend lines and data points that appeared in Al Gore’s movie and IPCC. For that matter, a new study has debunked McIntyre’s deconstruction of the Yamal data.
Instead of relying on urban legends, I request that WUWT commenters begin the laborious task of reading IPCC IV, with appendices and addenda.
Of course, if you believe that scientists are fraudulent by nature, there’s not much basis for discussion.
REPLY: Mike you miss the biggest point. Climatologists, particularly government funded ones, have no consequences for failure to perform in forecasting. McIntyre, being a mining statistician does – if he overstates a claim, investors will have it in court. Bastardi of Accu-Weather loses subscribers for his company if he fails to deliver. Myself and other TV weatherman will have viewer revolt, sinking ratings, and loss of advertisers if we don’t get it right very often.
Economists, they’ll be ignored if they botch it. For example, Alan Greenspan didn’t get respect by being bad at what he did. The people you name have to perform in the public eye, climatologists just move on to the next grant and the next paper. There’s little if any consequence for being wrong. They got a pass from the media until climategate came along and woke some of them up.
Climatologists may understand certain things “better” but that understanding doesn’t always equate to performance. I tend to see it as people that like you named above understand the same things, but differently. One mans conclusion is another’s unsupportable forecast.
I’ve forecasted sea ice to recover for the third year at summer minimum. I made that forecast right here on WUWT last fall. We’ll see how it performs. – A
David S (01:03:23) :
“Can anyone enlighten us as to the rationale for this gloriously named methodology, normally seen in digital filter processing? It seems to be a long way from home, and as far as I can see there is no innocent reason why it should have been used for weather observations.”
The explanation is almost certainly that Matlab has a standard function W=hamming(L). Some climate scientist who knows little about statistics and nothing about signal processing was playing around and found that this filter was the one that gave the result he wanted.
Same thing about using average padding for a smoothing function. This is ONLY allowable for data without a trend, so it proves either that IPCC does not understand statistics (which is not news), or that the IPCC does not think that temperatures change in a non-random way over time.
mike roddy (08:39:54) :
“On a more general note, you are asking us to believe temperature reconstructions put together by amateurs, rather than the ones carefully developed and peer reviewed by hundreds of specialists at NOAA, NASA, CRU, and others. It’s beside the point that your data is not correct.”
No amateur ever made a temperature reconstruction (McIntyre keeps saying he never did a temp reconstruction, and hoi polloi keep saying he did.) That’s for the tree-ring guys. Now, as it happens, it seems that these tree-ring guys and temperature homogenizing guys might be statistics amateurs.
The absence of statisticians in their teams has been cited as a reason for their failure, which can be seen above in a simple statistical methodological matter.
mike roddy (08:39:54) :
“On a more general note, you are asking us to believe temperature reconstructions put together by amateurs, rather than the ones carefully developed and peer reviewed by hundreds of specialists at NOAA, NASA, CRU…”
Who are the “amateurs” and who are the “specialists”? Do you have a copy of the curriculum vitae of everyone in the game? Does working for “NOAA, NASA, CRU” immediately, automatically, and magically confer upon an analyst the rank of “specialist”? Posters here have referred to the author as “Dr. Lansner”. Is it your contention that he received his PhD from a Crackerjack box?
Hundreds, even thousands, of peer reviewed “specialists” assured us in days past, against “amateur” opinion, of the physical impossibility of powered flight, of constructing super-sonic airplanes, of operating rocket ships beyond the atmosphere of the Earth, and of the universal invariance of time, to mention just a few.
Your complaint has no merit. It is complete ad verecundiam, one of the most basic logical fallacies.
jorgekafkazar (10:23:01) On the K and the ºK
Ah, Jorge, it’s not as you put it either, it’s even worse. You should use K, ºC, ºF, not ºK, C, F.
And don’t forget the space between the quantity and the unit: 2.3 K, 23.7 ºC, etc… If you intend to use the SI, that is: look here. I don’t know about the Imperial System.
I get regularly clobbered for saying these things 🙂 I should know better.
“Is it possible to “prove” that we had a solid MWP-consensus until year 2000? K.R. Frank Lansner”
The question sounds a lot simpler than it is. When I was a graduate student in geology, dozens of years before 2000, the MWP was taught as fact. So the basic question must be “Did anyone question the areal validity of the MWP before 2000?” Well, my memory isn’t that good, but the MWP was so well-known for so long from both geological and historical evidence, that it seems highly unlikely that nobody would notice that it only applied to Europe and America, especially since it has recently been reiterated that existing data showed it to be a world-wide phenomenon.
I think the reverse is the proper question. When the IPCC (was it Mann?) claimed the MWP was a local phenomenon, did they show any data to back up that claim? The answer is no, they didn’t. That’s when the questions should have been asked and it’s more than peculiar that scientists supporting AGW did not ask. None of them even asked the more obvious question, “How could one hemisphere have a totally different temperature profile than the other?”
It’s prima facie evidence of very poor science, if not outright fraud.
>>>Wilde
>>>Are we governed by the mentally challenged ?
You need to ask that question, I thought it axiomatic. 😉
.
P.S. Note to mods – ‘effect’ is the noun and ‘affect’ is the verb, you had it A over T.
.
Thanks Frank for highlighting this issue – it does get forgotton. Basically, if IPCC applied the same rules for the current period as they do for proxies, there would be no scary climate story. The instrumental record as a single global average of thousands of stations (with various adjustments!) cannot be directly compared to proxies because those proxies are a) not absolute measures of temperature – especially tree rings; b) only ever regional (even the Greenland Ice Core). If you are going to attempt to do it – by splicing the instrumental record onto the proxies – the Mannian and Jonesian Trickster Methodology then at least there should be transparency over how the calibration is performed – for example, the tree ring data would need to be used over the whole of the recent post-1980 warming (there being no warming from 1940-1978) – and we know that those data did not show warming so they were ‘truncated’ rather than admit the truth that the proxies were not reliable and the two data sets should not be compared.
I have come to the view – post-climategate, that we should abandon all global averages from the instrumental record prior to 1979, and stick with the modern era of satellite measurements – as well as abandon all attempts are computer prediction of temperatures for the next century. In the latter case, the current predicted range and uncertainty it next to useless for policy, especially given the regional levels of uncertainty for rainfall as well as temperature. We need to spend on resilience and adaptation to protect a burgeoning population of people very vulnerable to climate change – natural or otherwise, and mitigation was never going to be relevant over the next few decades at risk.
mike roddy (08:39:54) :
Historical temperature reconstruction, including those for recent decades, is a highly technical and detailed process, requiring extensive training.
Translation: “You’re not smart enough to do it unless you work for the government.”
Questioning the basic expertise and integrity of those who develop these global temperature charts for international organizations is not credible, and is unsupported by actual scientific evidence.
It’s credible when it’s supported by *physical* evidence, though. Just the code and Harry’s commentary were enough to convince even a casual reader that the people who wrote it were as “expert” as a squad of penguins trying to play basketball.