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Paul Dennis on the trick

Someone called Paul Dennis is commenting on the Simon Singh thread. I assume this is the paleoclimatologist of that name who works at UEA.

He agrees with my take on the trick to hide the decline.

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Reader Comments (41)

Hmmmm. Double hmmmm.

Jan 29, 2011 at 12:52 PM | Unregistered Commenterkim

Every climate scientist under the sun - indeed every scientist - should agree with Bishop Hill's take on hide the decline. It's that basic. The fact climate science chose to defend the indefensible (from 2003, when McIntyre and McKitrick first published) and to demonise its critics rather than engage with them (from 2004, when the disgusting comparison with Holocaust deniers began) led to the terrible state we're in now. But one senses that things they are, finally, a-changing. If that is the Paul Dennis of UEA, good on him. A harbinger of much more to come.

Jan 29, 2011 at 1:00 PM | Unregistered CommenterRichard Drake

The blogosphere moves very fast. Yes I am the Paul Dennis from UEA but I wouldn't label myself as a palaeoclimatologist. I'm an isotope geochemist who has dabbled a little with palaeoclimatology.

Basically, I agree with the Bishop.

First, however, let me say there are several legitimate reasons why one might want to splice the tree ring data to the temperature record. For example it would be necessary to do so when looking at 'in calibration' and the projections of 'out of calibration' periods with the instrumental record. In doing so, however, one would include the complete data set showing both periods of good and poor tree ring response.

What I don't think is good scientific practice is to select a portion of the tree ring record that agrees with the instrumental record, say pre-1960, and splice onto this the instrumental record, without showing the divergence. The divergence is strong evidence that trees do not respond to temperature in a simple linear manner. Given that there is nothing significantly different about post 1960 conditions and past conditions then one surmises that tree response to temperature and other climatic variables is highly non linear and without a better understanding of their bio-physical response to growth conditions they are, in my view, unsuited as proxies for temperature reconstructions.

What concerns me about the 'hide the decline' debate is just that. The divergence in tree response to temperature was hidden without an adequate discussion of the reasons why. The decline doesn't point to the unreliability of the modern instrumental temperature record. It highlights the poor control we have on past temperatures and our inability robustly to estimate what these are likely to be. This goes to the heart of the debate over whether modern temperatures and rates of climate change are unprecedented or not. I strongly suspect that in both cases the answer is a negative.

By hiding the divergence one's attention is drawn away from the uncertainties of the palaeoclimate record.

Jan 29, 2011 at 1:11 PM | Unregistered CommenterPaul Dennis


Nice to see you back here again and thanks for your interventions at Simon Singh's. I wonder if it might help matters if you were to identify yourself over there as someone who has relevant expertise. People like Singh are accepting the received wisdom and might be surprised to learn that people working in the area have different opinions on the acceptability of what was done.

Jan 29, 2011 at 1:17 PM | Registered CommenterBishop Hill


Jan 29, 2011 at 1:38 PM | Unregistered CommenterPaul Dennis


Jan 29, 2011 at 1:47 PM | Registered CommenterBishop Hill

Thank you Paul. Well said.

Jan 29, 2011 at 1:48 PM | Unregistered CommenterPhillip Bratby

Paul & Andrew:
Simon and Nurse demonstrate that really smart people can be very close-minded when it comes to certain subjects. Good luck with any effort to get Simon to re-evaluate his position. The hide the decline issue, so well summarized by both of you, is so obviously wrong it is extremely hard to understand why anyone would refuse to acknowledge Jones' and Mann's error.

Jan 29, 2011 at 1:54 PM | Unregistered Commenterbernie

As I've posted previously:

In the Horizon programme at about 21m17s, Jones explains to Nurse that the "trick" graph was featured in the "WMO Statement on the Status of the Global Climate in 1999" (pdf available online). He makes it pretty clear that even he saw the final result as advocacy rather than science.


The Organization wanted a relatively simple diagram for their particular audience. What we started off doing was the three series with the instrumental temperatures on the end, clearly differentiated from the tree ring series, but they thought that was too complicated to explain to their audience. So what we did was just to add them on and to bring them up to the present.

Jan 29, 2011 at 2:19 PM | Unregistered CommenterScottie

Simon Singh, the particle physicist appears to read John Cook the physicist's articles to inform himself. The problem starts there.

Jan 29, 2011 at 2:41 PM | Unregistered CommenterShub

Thanks for the specific reference. However, IMO, this does not address the obvious issue that Paul Dennis and many others have pointed out - the divergence means that tree rings as proxies for historical temperatures have significant problems that need to be addressed independently of any advocacy. The email record indicates that Briffa, at one point, fully understood this.

Jan 29, 2011 at 2:53 PM | Unregistered Commenterbernie


"So what we did was just to add them on and to bring them up to the present."

So does that limit Prof Jones's involvement as being that of a graphic artist?

Jan 29, 2011 at 3:07 PM | Unregistered CommenterGreen Sand

Bernie, you hit the nail on the head with your, “really smart people can be closed minded when it comes to certain subjects". Really smart people can be stupid when it comes to certain subjects. Usually when they pontificate about other people's subjects (Nurse and Singh), but often they can be just as wrong on their own field.

Science is full of ‘consensus’ issues where everybody had it wrong. Two that immediately spring to mind are Wegoner and continental drift, and the Heliobacta–that won the Nobel Prize for its discoverer.

That said, it is a shame about Singh and Goldacre. They are both important figures, but are letting themselves down.

Jan 29, 2011 at 3:15 PM | Unregistered CommenterStuck-record

Paul Dennis' comment is right on the money. The main point is the divergence. The divergence throws into doubt the usefulness of tree ring proxies for climate reconstruction. The fact that Jones and the team did not acknowledge this truth revealed their hubris and maybe more. During the fierce debates at the Guardian website that followed disclosure of the Climategate emails, no one would address this point. Dennis' comment here is another breath of fresh air.

Jan 29, 2011 at 3:16 PM | Unregistered CommenterTheo Goodwin

I'd love to be a fly on the wall in the Senior Coffee Room at UEA when Jones et al next bump into the courageous Mr Dennis.

Jan 29, 2011 at 4:01 PM | Unregistered CommenterLatimer Alder

1. If the reported instrumental record has been the subject of systematic, advocacy-oriented exageration, the observed divergence makes perfect sense.

2. On the few occasions where a (dendro) proxy reconstruction has been accompanied by a sample count for each year of the reconstruction, the period over which the divergence occurs is hideously undersampled w.r.t. the preceding few hundred years. Thus, the apparent fit might be nothing more than coincidence, given the paucity of samples, and the subsequent divergence proof that the apparent fit was nothing more than coincidence.

Jan 29, 2011 at 4:07 PM | Unregistered Commenterbeep

Heh, LA, a confederation of pathetic cowards.

Jan 29, 2011 at 4:34 PM | Unregistered Commenterkim

What I find amusing is that Jones attempts to excuse his behaviour by blaming the WMO. The worst of the behaviour is that he doesn't immediately acknowledge the violation of uniformitarianism.

The Bish is eloquent over at Mr. Singh's, but chippie has the crowd on its feet and roaring.

Jan 29, 2011 at 4:54 PM | Unregistered Commenterkim

If A correlates with B for 150 years and A doesn't correlate with B for the next 50 years, then A doesn't correlate with B. Hence trees are not good thermometers.

Jan 29, 2011 at 5:08 PM | Unregistered CommenterPhillip Bratby

Paul Dennis said

... I'm an Isotope Geochemist and Head of the Stable Isotope and Noble Gas Laboratories in the School of Environmental Sciences at the University of East Anglia. I've also contributed to and published a large number of peer reviewed scientific papers in the general field of palaoclimate studies. I don't say this because I think my views should carry any more weight. They shouldn't.

So he wants to base scientific arguments on science, instead of appeals to authority. Sounds like a true scientist. I wish that there were more.

Jan 29, 2011 at 5:25 PM | Unregistered Commenterpoiuyt

Paul Dennis and Phillip Bratby are spot on.

Either the President of the Royal Society does not understand this simple argument, or he does understand it but thinks that lying about what the data means is acceptable behaviour for a scientist. It is hard to know which of these two possibilities is more shocking.

Jan 29, 2011 at 5:28 PM | Unregistered CommenterJonathan Jones


Yes, I agree totally - I think it's generally accepted that tree rings are not necessarily a good proxy for temperature.

But my point is that in the Horizon programme, Jones casually acknowledges that he altered his original graph to suit the (advocacy) needs of the WMO. And as the Climategate emails show, this culture appears to be all-pervasive in climate science.

Climate scientists don't seem to have a problem with that!

Jan 29, 2011 at 5:37 PM | Unregistered CommenterScottie


Excellent to see you bravely joining the fray. You eloquently said what I espouse in full frustration mode.

In my world (NASA) this kind of covering up the real core data and conclusions is tantamount to criminal fraud. It is not dissimilar from covering up how solid-rocket booster O-Rings respond to temperature, especially in the colder regions. Here it is the modern temperatures, but the same sad game. In the case of Challenger (and other issues NASA has experienced) these kinds of cover ups are not innocent nor trivial. They endanger many people. For example, we were extremely lucky Columbia's break up on reentry did not leave a swath of destruction on the ground. Even well intentioned short cuts can be reasonably considered criminal negligence. Ego is not a defense when it can be shown the cover mistaken conclusions are directly related to false impression left by false data.

As you noted, the cover up here hid the inconvenient truth that (a) tree rings do not reflect temperature (local or otherwise) and therefore (b) we have no evidence the Current Warming Period is significantly warmer than previous warm periods. In fact, given what ice cores show (being non-organic proxies) the evidence still stands that the CWP does not reach the levels of the RWP and MWP.

I know scientists and engineers do not like to let disagreement be challenged in the courts, but in this case one has to wonder why there has been no public walking back after a decade of beating the hockey stick into a mass of bad science and misinformation. The leniency period for the acceptance of good intentions but wrong actions is long gone. The fact so many still claim this is solid instead of nauseatingly foul many years on indicates how far the rot has set in.

Anyway, thanks for the good fight to keep science and engineering a respectable and valued profession.

Jan 29, 2011 at 5:49 PM | Unregistered CommenterAJStrata

Green sand......"So what we did was just to add them on and to bring them up to the present."

So does that limit Prof Jones's involvement as being that of a graphic artist?

.......Most Graphic Artists would think that was wrong.And would indicate in some way, that it was data from two different sources.......Did you think that Artists have no integrity?

Jan 29, 2011 at 6:12 PM | Unregistered CommenterFenbeagle


I stand truly and correctly admonished!

Jan 29, 2011 at 6:26 PM | Unregistered CommenterGreen Sand

If people like Paul Dennis from UEA are 'coming out' this gives me hope that the science will out in the end.
Too many people in the scientific community in all our universities have simply kept their heads down, with the result that the reputation of all scientists has been tarnished.
Lets hope more people will 'come out' and stand up for the science, not the politics.

Jan 29, 2011 at 7:33 PM | Unregistered Commenterconfused

Oh right, so its all the fault of the WMO back in 1999 that the similar fudged graph appeared in the 2001 IPCC report. Thanks Prof for clearing that up.

Jan 29, 2011 at 7:49 PM | Unregistered CommenterMartyn

hro001 aka Hilary Ostrov, called Paul Dennis a breath of fresh air from UEA, nearly a year ago on a WUWT thread (February 10, 2010 at 11:06 am)

quoting at length from Paul's now mothballed blog on his essay on Jerome Ravetz and Post-normal science

He impressed me then, and returns so to do once more, so I propose that Hilary's 'breath of fresh air from UEA' handle be awarded to Paul as fitting honour to match Judith Curry's Josh T-shirt.

Jan 29, 2011 at 8:31 PM | Unregistered CommenterPharos

Is it just me or is the jury out on Phil Jones' culpibility in this issue? I mean...he has said some quite dramatic things, furthering the skeptics case - flat temps for example. Did he find himself in an impossible position between his paymasters and his integrity? Is he 'Harry'..?

Dunno...don't know the guy from Adam, but, irrespective of his emails (maybe playing the game) is he struggling to let the truth out without jeopardising funding/employment of his colleagues and friends ( many of us would act differently when it was our friends mortgage under threat?)
I find some of Briffa comments the same way...reluctantly allowing data to be used in a way they personally would not approve of?

Paul Dennis' posts here give me hope this may be so (watch your back Paul? Governments do not like having the rug pulled from under them?).

On the other hand, I find nothing in Michael Manns demeanour of any credit whatsoever.

Just wondering.

Jan 29, 2011 at 9:08 PM | Unregistered Commentermikef2

One thing puzzles me about both Simon Singh and Ben Goldacre. I've read Singh's Big Bang and enjoyed it very much, since he has the gift for explaining complex scientific ideas in a way a non-scientific but interested bystander like me can understand. One of the threads in the book is how mavericks all the way from Gallileo kicked against the prevailing consensus and, though there were a few dead-ends along the way, led us to our current comprehension of what the Big Bang was and what it means. He is also at pains to point out that this is only our current comprehension: future discoveries may overturn that.

I've also read Goldacre's Bad Science and enjoyed that very much. Once again, the message came through strongly: the consensus is not always right and indeed, may be lethally wrong, particularly if the media picks up the wrong end of the stick and runs with it. Chapter 10, "Is Mainstream Medicine Evil?" is an easily understood lesson on how data can be skewed, amputated and generally tortured to fit an a priori result.

Yet both men rest their support for AGW largely on "scientific consensus", ignore the data torturing that has been revealed in books such as The Hockey Stick Illusion and generally throw the scientific method baby out with their own published bathwater. As I say, it's a puzzle.

Jan 29, 2011 at 11:42 PM | Unregistered Commentermorpork

I visited Simon Singh's website and read some of the posts. Then I took a shower. Now I can comment on the posts. With the exception of posts by Dennis, Hill, and a couple more, they read like posts by paid Pit Bulls whose goal is to wear down the energy of sceptics. Someone made the absurd claim that Jones' "hide the decline' trick was to clarify matters. It is obvious to anyone not wearing Warmista blinders that the trick had the effect of hiding the divergence between tree ring and thermometer data for the fifty years after 1960 and, thereby, hiding powerful evidence that tree rings are not reliable as a proxy for temperatures. As regards Pit Bulls, their most offensive tactic is to answer a question with a reference to a paper, as if they were teachers assigning homework. Needless to say, all this tactic accomplishes is to pile on yet more evidence that they do not have the ability to defend their position in their own words. I really cannot understand why anyone would read Singh's website.

Jan 30, 2011 at 12:42 AM | Unregistered CommenterTheo Goodwin

@morpork: "Yet both men rest their support for AGW largely on "scientific consensus", ignore the data torturing that has been revealed in books such as The Hockey Stick Illusion and generally throw the scientific method baby out with their own published bathwater. As I say, it's a puzzle."

I believe it's to do with politics and class. Both men are children of their class, the metro elite and wouldn't be out of place in the dining rooms of Notting Hill and Islington. From the very beginning the green activists have painted sceptics (I prefer they use "deniers" by the way, it clearly demonstrates the paucity of their arguments) as a bunch of non-scientific right wing loons, and both men have decided to take the position of their "class" on the issue. Indeed it would be impossible for people with their background to do otherwise unless they had social courage way beyond the call of duty, else they would either be ostracized, or ridiculed, by their friends. Don't expect a conversion from either anytime soon, it will be others, and of course the passing of time, who point to the similarities of the basis for, and spread of, the great religions, and the demands from their adherents to the strict beliefs of their folklores, even though the tenets had some common sense, and the AGW scare.

As for the hiding of the decline, it is widespread in climate science, it is unique in my view in the number of scientists who spend their time trying to prove the theory of AGW right. Once a scientist starts out trying to prove a hypothesis is right we are in deep doo doo because they, the scientists are just like the rest of us (they even choose complete buffoons to lead and represent them) and will fudge things if the data doesn't fit the theory. We could do with setting up a school of scientists whose sole job it is is to attack the theory of AGW and then see what answers we get then. On second thoughts setting up a team to prove something is wrong means that if they're successful they'll be out of a job doesn't sound like it's going to fly.

Jan 30, 2011 at 1:08 AM | Unregistered Commentergeronimo

geronimo writes:
"Indeed it would be impossible for people with their background to do otherwise unless they had social courage way beyond the call of duty, else they would either be ostracized, or ridiculed, by their friends."

Sounds like Senator Kerry from Massachusetts.

Jan 30, 2011 at 1:26 AM | Unregistered CommenterTheo Goodwin

Singh has become enormously pompous and pleased with himself -- note how he describes himself as 'insightful' for supposedly coining the aphorism:

"I would suggest that people who take part in the climate change debate are all intelligent, honourable and reject manmade climate change, but they never possess more than two of these qualities at once.

Of course, this jibe has been around in one form or another for as long as I can remember.

I might make the same observation about those who embrace manmade climate change, but I'd reduce the required number of attributes to one.

Jan 30, 2011 at 3:13 AM | Unregistered CommenterRick Bradford

I had a look over at Singh's thread but didn't fancy posting there - the argument seems to have fizzled out and there seem to be problems with some of the posts. On the "hide the decline" I think this is indefensible for pro-AGW proponents. One contributor wrote:

"The tree ring data shows a very close between growth and temperature as measured by instrumentation, from about 1880 until 1960. It's better to use the tree-ring data prior to the discrepancy forming because you have data from all over the world and for each year– as opposed to the slightly scattershot early weather experiments. Once the divergence occurs (an as-yet unexplained phenomenon, and v. interesting in its own right) it becomes more accurate to use instrumental data."

This is baloney. Removal of data that does not fit the theory is known as "trimming" and is totally unjustifiable. It is essentially a way of trying to pretend to yourself (and others) that you have a correlation when in fact you don't. Trimming can be difficult to detect in reports and that is the case in the "hide the decline" saga.

A failure by scientists to report trimming of data would be scientific fraud, pure and simple. (Note that is not an accusation but a statement).

Jan 30, 2011 at 9:47 AM | Unregistered CommenterThinkingScientist

Geronimo said:

"As for the hiding of the decline, it is widespread in climate science, it is unique in my view in the number of scientists who spend their time trying to prove the theory of AGW right. Once a scientist starts out trying to prove a hypothesis is right we are in deep doo doo because they..."

Karl Popper argued very eloquently and convincingly that you cannot prove a theory true, only demonstrate that it is false. The author of the Wikipedia page states it beautifully:

"Logically, no number of positive outcomes at the level of experimental testing can confirm a scientific theory, but a single counterexample is logically decisive: it shows the theory, from which the implication is derived, to be false. The term "falsifiable" does not mean something is false; rather, that if it is false, then this can be shown by observation or experiment. Popper's account of the logical asymmetry between verification and falsifiability lies at the heart of his philosophy of science. It also inspired him to take falsifiability as his criterion of demarcation between what is and is not genuinely scientific: a theory should be considered scientific if and only if it is falsifiable."

Note also the last sentence: "a theory should be considered scientific if and only if it is falsifiable". That, to me, is why AGW is wrong and is essentially a religion not science. We can falsify predictions made by climate scientists for the last ten years (from IPCC 2001) very easily:

1. Temperatures were predicted to continue rising. This is clearly false.
2. Sea level was predicted to rise at an accelerated rate and the predicted rise was 6 m over 100 years, which is 60 cm (2 feet!) over 10 years. This is clearly false. Sea level rise has not accelerated and a rise of 60 cm has not taken place over 10 years.
3. The climate models predict a "hot spot" in the middle atmoshpere. This has not been detected.

I think my favourite comment from climate scientists was the claim that all possible natural forcings were included in their models and the only explanation is CO2. Apart from the staggering hubris of saying you already know everyhting about predicting climate, climate scientists now explain the lack of warming as being due to natural effects temporarily exceeding AGW CO2 effects (Don't remember you predicting that before it happened!). Talk about have your cake and eat it.

Jan 30, 2011 at 10:04 AM | Unregistered CommenterThinkingScientist

geronimo: "I believe it's to do with politics and class. Both men are children of their class, the metro elite"

That sounds very plausible to me. I've been struck by how many commenters on sceptic blogs make reference to their rural locations. Most people in the West live in big cities but, impressionistically, many sceptics do not. If you are an engineer or geologist living in Crinkley Bottom, then the prejudices of the metro elite can be happily ignored.

Jan 30, 2011 at 10:18 AM | Unregistered CommenterJane Coles

I was so struck by the Singh quote above ("intelligent, honourable and reject manmade climate change," etc.) that I tracked down his first use of it at "Climate change numpties: Simon Singh's guide for the perplexed" <>

It's recommended reading. Star quote:

I suspect that climate numpties (numpty (noun): a reckless, absent-minded or unwise person) are far more common than we might think, and they can be found in the most surprising of places.

This became apparent to me when I was having lunch one day with five physics undergraduates from a London college. They were clearly bright, devoted to physics and fully paid-up fans of the scientific method. However, not one of them was committed to the notions that climate change was happening, that it was largely caused by human activity (eg the burning of fossil fuels) and that there would be trouble ahead unless something changed.

I was baffled...

Perhaps bafflement will be the first step towards enlightenment.


Jan 30, 2011 at 2:04 PM | Unregistered CommenterChris Cooper

I apologise for being the person who has to share some bad news with
you but as I have just come across the climate change argument I felt
that I had to bring to your attention a fundamental flaw in your argument.

I know that it seems logical to assume that tree rings are influenced
by temperature and rainfall, but several studies have shown that this
is not the case. Two in particular, which lasted 10 years each and
measured the growth of trees three times a day over that period
categorically confirmed that trees do not grow in relation to
temperature, humidity, light or any other local variable. The two
most important factors that affect a trees growth are sunspot activity
and gravitational forces.

If you want to look at the evidence behind this you can have a look at
my book, chapter 3 page 46, at

I am sorry to have to bring this to your attention but I was not aware
that this debate had got so out of hand.

Feb 2, 2011 at 8:25 PM | Unregistered CommenterMatthew Silverstone


Thanks for your contribution. You may be surprised to hear that this a subject that has received regular discussion on sceptic blogs, particularly Climate Audit.

Paleoclimatologists argue that trees at the upper treelines on the sides of mountains, or those at the northern limit of their geographical range, do respond to temperature. This, however, is an assertion rather than something that has been demonstrated empirically. It's one of the things we complain about.

Feb 2, 2011 at 8:44 PM | Registered CommenterBishop Hill

I am not sure why though, ten years of daily readings that prove there is no relationship between temperature and tree rings is not accepted as good enough. I would argue that most climatologists have not read the data and therefore argue against something that they know nothing about.

Feb 16, 2011 at 5:52 PM | Unregistered CommenterMatthew Silverstone

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