In a Climategate email. Keith Briffa famously sneered at Michael Mann’s claim that a temperature reconstruction could represent a hemisphere, including the tropics, by regressing a “few poorly temperature respresentative tropical series” against “any other target series” – even the trend of Mann’s own “self-opinionated verbiage” as follows:
I am sick to death of Mann stating his reconstruction represents the tropical area just because it contains a few (poorly temperature representative ) tropical series. He is just as capable of regressing these data again any other “target” series , such as the increasing trend of self-opinionated verbage he has produced over the last few years , and … (better say no more)
People frequently say that the PAGES2K reconstruction has “vindicated” Mannian reconstructions – but neglect to mention that PAGES2K similarly regressed a “few poorly temperature representative tropical series” onto an increasing trend – thus, repeating, rather than vindicating, (one of) Mann’s erroneous methodologies.
In today’s article on the Hockey Stick featured in the new IPCC Hockey Stick diagram, I’ll look at proxies in the southern tropics (0-30S latband). The proxy network turns out to be defective in bizarre, unexpected ways, not reported on or discussed in the original article.
The 0-30S Network
The 0-30S latitude band is mostly Indo-Pacific tropical ocean, but includes most of Australia and South America and the lower part of Africa.
The PAGES2K 0-30S proxy network has 46 proxies (as compared to 8 proxies in the 60-30S network). It has one – yes, one – proxy from an ocean cores and two proxies from land. 43 of 46 series are very short coral series.
The 0-30S network only has two (!?!) proxies with values prior to AD1500: the ocean core (a temperature estimate from Mg/Ca at Makassar Strait, Indonesia [Oppo et al, Nature 2009] and the classic ice core d18O series from Quelccaya, Peru (as updated in 2013) that had been staple of Mann et al 1998-99, Jones et al 1998 and many other studies. Neither of these series contains a hockey stick; if you squint, you can discern lower values in each in a generalized LIA period.
Indeed, there are only two other 0-30S proxies that begin prior to AD1600: the Hendy (2002) Great Barrier Reef temperature reconstruction that does not have a HS; an Indonesian tree ring series (INDO0005) that is non-descript in the underlying measurement (rwl) data at NOAA, but which, according to a thus far undisclosed calculation, closes on a late spike – like numerous other sites in the PAGES2K Asia tree ring calculations. I’ve sought information on this chronology from the lead authors of PAGES2K 2019 but they don’t know and have refused to bother finding out.
The rest of the 0-30S network consists of 42(!) short and micro-short coral series. Below is a histogram of start dates for the 43 (including Hendy GBR) coral proxies. Half of them start after AD1850 and no less than 30% after AD1890. One series (Clipperton Atoll, Wu [2014]) begins in AD1942 !?! None of these short series shed any light on whether the medieval period, for example, was warmer than modern period or not.
Most of the coral proxies show substantial change in d18O and/or Sr/Ca in the 20th century. Here is a random sample of 9 (which, by chance, included the Hendy series shown above). The Hendy series is very different than typical series: PAGES2K is primarily populated with d18O series – which, in specialist articles, are seldom, if ever, used as temperature proxies, as Sr/Ca is usually preferred. Changes in 20th century coral d18O are nearly always much more pronounced than corresponding changes in coral Sr/Ca. Perhaps that’s why they were selectively chosen into the PAGES2K network.
Coral d18O is very responsive to rainfall amount and many 0-30S coral series are located along convergence zones where there is very strong latitudinal or longitudinal gradient in rainfall (and thus d18O). This is a large topic that ought to have been discussed by PAGES2K in explanation of their preference for d18O series. (I have extensive notes on this issue and will try to re-visit.) That these series go “down” doesn’t matter as more negative values are (ex ante) believed to represent higher temperatures (as opposed to the too prevalent ex post cherry picking).
Conclusion
How the PAGES2K authors obtained a big-bladed Hockey Stick from this data cannot be determined without examining their code, which, to my knowledge, has not been archived. (Nor have it been provided to me upon tweet request.) My surmise is that they use some sort of “stepwise” method in which successive steps incorporate the proxies available in that step. Such techniques will effectively splice the coral blade onto the two non-descript non-bladed long proxies to present a sort of hockey stick. The failure of the two long proxies to record the proposed blade means that the confidence levels prior to AD1800 or so extend from the “floor to the ceiling” – an apt phrase used by Rosanne d’Arrigo many years ago. I.e. with this set of information, we know essentially nothing about 0-30S temperatures prior to AD1800 or so. This does not mean that we actually know nothing. There are many interesting proxies in the 0-30S latband and many fascinating discussions in technical literature that does not appear to be reflected in the IPCC report.
Consolidating some of the information in this post with my prior post on the 30-60S latband, which consisted almost entirely (~96%) of ocean, PAGES2K only used one ocean core in the 0-60S latband, totally omitting high resolution alkenone series. Only four PAGES2019 series in the 0-60S latband start prior to AD1100 and none of them have a HS shape.
Overall, I think that it’s fair to say that Briffa’s criticism of Mann remains just as appropriate for the IPCC in 2021, as it did in 2001. Like Mann’s network, PAGES 2019 “contains a few (poorly temperature representative ) tropical series”. And PAGES 2019 authors “were just as capable [as Mann] of regressing these data again any other “target” series , such as the increasing trend of self-opinionated verbage he has produced over the last few years”. Indeed, if anything, the new generation of climate activists have proved themselves more than capable of continuing Mann’s “trend of self-opinionated verbiage” to, shall we say, “unprecedented” levels.
Climate Audit 
86 Comments
Thnx for the post. You could add the 0-30 S Pages19 reconstruction to show the blade.
if I recall correctly I believe in the SI of the Neukom19 paper it is explained how they made the reconstructions.
I’ve read the text in Neukom SI. I’m knowledeable in such matters, but have no idea how to reliably replicate their methodology based on their text. They appear to have tricked Nature by providing code for generating figures from reconstructions – nice, but not central to anything – but omitted code for generating reconstructions.
Perhaps Nature can insist authors to disclose. Not sure what their policy is.
Reblogged this on ClimateTheTruth.com.
“if you squint, you can discern lower values in each in a generalized LIA period.”
Steve McIntyre, squinting is not a scientific procedure! If you wanted to present proper scientific arguments, you would have included a Loess fitting or a moving average in these graphs. But that would have shown that the temperature variation in these series varies by 0,5°C or so at timescales of centuries, whereas it has increased by 0,8°C in the most recent 40 years.
Squinting hard enough I can discern overlaid on a hockey stick a lacrosse stick badminton racket and a polo mallet but with the last controversy I’m prepared to concede it could be a croquet mallet in the interests of settled science.
Then why don’t the proxies show it, Bas?
the Quelccaya series is d18O. Most specialist authors believe that d18O series in tropical zones measure “amount” of precipitation rather than deg C; Lonnie Thompson has long that they measure temperature – an interpretation presumably followed by PAGES2K. My own take is that d18O in tropical zones measures amount of precipitation and is an index of monsoon strength and thus ITCZ location.
Merely adding a smooth to a d18O series doesn’t convert the series into deg C.
Looking at data is an important part of data analysis. Unsmoothed data contains more information than smoothed data. Sometimes smoothing is helpful, but I generally like to see the unsmoothed data as well. In this case, the point is that neither series looks remotely like the PAGES Hockey Stick and do not demonstrate its existence in the proxies in this latband that extend back to the medieval period.
“Looking at data is an important part of data analysis”
Yes, but doing that by squinting is a very unscientific way of doing it.
You also misinterpret my point by suggesting that I would ignore the raw data (“i generally like to see the unsmoothed data as well”): both raw and properly smoothed data are important.
The point is that these series vary by 0,5°C or so at timescales of centuries, whereas it has increased by 0,8°C in the most recent 40 years. Why didn’t you reply to that part of my message?
Suddenly starting on precipitation is completely irrelevant when addressing my point on smoothing or the recent 0.8 warming. That is “moving the goalposts”, a strategy often used by people who don’t want to admit the other party has a valid point….
Bas wrote:
“The point is that these series vary by 0,5°C or so at timescales of centuries, whereas it has increased by 0,8°C in the most recent 40 years.”
SM wrote:
“Such techniques will effectively splice the [+0.8] coral blade onto the two [+/- 0.5] non-descript non-bladed long proxies to present a sort of hockey stick.”
If you actually have a point, please explain why you think these numbers refute something in the blog post. It is not obvious from what you wrote.
Huh, you obviously don’t understand these proxy series. The Quelccaya series is a tropical d18O series. All we know is whether the d18O values go up or down. Lonnie Thompson thinks that tropical ice core d18O is a proxy for temperature; most specialists think it is a proxy for precipitation. I wasn’t “changing” the topic. I was discussing the Quelccaya proxy – on which I’ve written numerous blog posts. The PAGES reconstruction shows a huge blade. There is no such blade in the proxies going back to medieval period.
for your reference, here is a discussion of South American proxies in PAGES 2013, which also used the Quelccaya d18O series, but, interestingly, used it upside down to the orientation that is used in PAGES 2019.
“Huh, you obviously don’t understand these proxy series”
Why the ad hominem reaction? I am not a climate scientist, but neither are you. You criticize climate science for almost 20 years, but still you have not been able to convince a single climate scientist that the hockeysticks are poor science. You have not been able to get a retraction of any of the publications on hockeysticks because of improper dataset selection of improper statistics. What does that say about your arguments? It rather looks that you overestimate your own understanding, are unwilling to accept that the rest of the scientific world sees your arguments as invalid and so you resort to blogging rather than discussions with scientists, because you cannot accept that you are not right.
Suddenly starting on precipitation to reply to me while this was not addressed in the article is completely irrelevant when addressing my point on smoothing or the recent 0.8 warming. That is “moving the goalposts”, a strategy often used by people who don’t want to admit the other party has a valid point….
you say “you have not been able to convince a single climate scientist that the hockeysticks are poor science”.
Many scientists agreed with our criticism of Mann’s methodology and proxies. Even the current chair of IPCC WG1 told me in a conversation at AGU that she thought that our criticism of Mann’s methodology and proxies was convincing.
There are many non-political articles on the Holocene. Articles applying convoluted multivariate methods to multiple proxies play little to no role in virtually any of them. Accordingly, the Hockey Stick plays little to no role in majority of professional paleoclimate literature.
On the issue of availability of data and even code – an issue that was controversial at the time and hotly opposed by Mann and other climate scientists- I’m definitely on the right side of history, as all of the policies that I advocated are now acknowledged even by climate scientists.
“The point is that these series vary by 0,5°C or so at timescales of centuries”
I don’t see temperature displayed for the proxy series in the post. The scale of each proxy depends on what was measured, and it isn’t temperature that was measured. So I don’t understand how you can make the statement that they only vary by .5C.
“Suddenly starting on precipitation to reply to me while this was not addressed in the article.”
Again I’m not sure why you are writing this. From the article. “Coral d18O is very responsive to rainfall amount…”
Any research, in any field of science, has limitations and can be criticized. That doesn’t invalidate it and doesn’t mean it is poor science. So my point is still valid: “you have not been able to convince a single climate scientist that the hockeysticks are poor science”.
Availability of data and code has been discussed in all fields of science, not just climate science, and has become much more accepted. You may be on the right side, but you will also only be a small footnote on this issue.
The hockeystick may be irrelevant for paleoclimate research, but it is very relevant for research on today’s climate, so don’t move the goalposts (again). The key message of the hockeystick remains: temperature varied by 0,5°C or so at timescales of centuries, whereas it has increased by 0,8°C in the most recent 40 years. Temperature increased much more rapid in the past 40 years than in the previous 2000 years. In the past 20 years, you have not presented any credible arguments to question or invalidate that conclusion.
Bas, The hockey stick is very relevant to paleoclimate research, and today’s. From your replies I sense you are not up to date on paleoclimate literature. See eg Buntgen et al 2020
Bas,
If you accept the Pages temperature record as accurate, and you don’t accept that these are valid criticisms that is fine. It would be better if you had a specific response to the post other than just saying that the Pages temperature record is accurate. That IMO doesn’t add to the discussion.
To be specific the .5C claim is simply accepting the original paper. It has nothing to do with this post which displays proxies and units which are not temperatures.
Nicolas,
I didn’t write that I accept Pages2K-2019 as “accurate”, but I observe that essentially all climate scientists accept is as a scientifically sound best estimate. I also observe that they accept it has limitations and can be criticized, but that it provides valid conclusions within these limitations.
Steve McIntyre has been criticizing for years, but never provided a constructive contribution to the discussion. He has never shown assembled proxies himself and combined them in his own graph. He has never acknowledged that -despite the limitations- it is clear that the current temperatures and speed of temperature increase are unprecedented in the Common Era. In the past 20 years, he has not presented any credible arguments to question or invalidate that overall conclusion. His criticism without constructive participation only feeds the climate pseudosceptics. He is a merchant of doubt, not someone who participates in a scientific debate.
“whereas it has increased by 0,8°C in the most recent 40 years.”
Where? There is no “it”, meaning there is no global temperature, or anomaly. It’s a fantasy. Perhaps some places have warmed by that much, others have cooled, and others have remained relatively static. You can’t combine them all and come up with anything meaningful.
Bas wrote:
“Steve McIntyre has been criticizing for years, but never provided a constructive contribution to the discussion”
As someone who has clearly just joined the discussion and has no idea about what has previously been written, do you think you might be just parroting things which have been fed to you by other sources, without knowing the facts ?
To say that Steve has contributed no serious criticisms is just a joke. It is an entirely laughable statement. To say that he should make his own proxy record has been said many times, mainly as a deflection of his otherwise correct criticisms of what has been done by others. Such a statement is entirely unscientific. You don’t tell people who point out errors in things they should do it themselves. You should thank them, that is the scientific way.
It may be impossible to make a usably accurate representation of historic temperatures using modern proxies. Let’s not kid ourselves that pointing out such things as proxies being used upside down, algorithms used generating hockey sticks from noise, reconstruction shape being dependent on one or two proxies due to the algorithm, amongst his many other criticisms (none of which were disclosed in the publications themselves), is not valid criticism just because he hasn’t made his own.
None wrote: “As someone who has clearly just joined the discussion and has no idea about what has previously been written, do you think you might be just parroting things which have been fed to you by other sources, without knowing the facts ?”
Maybe I wrote the same as others, but I am not parroting. I just observe that I cannot find any graphs where McIntyre has assembled proxies himself. That is not deflection -it goes to the core of scientific progress. Science doesn’t progress by criticizing others, but by performing and presenting your own research. McIntyre has been asking for years for code of others. That implies that he understands code and can script and run it himself, but he has never presented anything. If he has done it and failed to get a hockeystick, we would have heard it. So either he cannot actually do this (and asking for code is a bluff), or he is too lazy to try it (which is hard to justify and he should stop criticizing), or he has done it but came up with a hockeystick as well (and not presenting it is in that case very doubtful behavior).
You also wrote “Let’s not kid ourselves that pointing out such things as proxies being used upside down, algorithms used generating hockey sticks from noise,…”. I believe that you are now parroting what you have read on this blog. Maybe you should also look elsewhere, to find out that many of these points have been debunked. There is a reason why climate scientists aren’t convinced by his arguments and it is not because they are all in big conspiracy to ignore him.
Bas:
“Maybe I wrote the same as others, but I am not parroting.”
Well I will give you the benefit of the doubt – but it has been said so often, and to me is such a ludicrous statement for anyone with any kind of science background to hear, I always feel it can only be a repetition, rather than being the product of reasonable thought.
“That is not deflection -it goes to the core of scientific progress. Science doesn’t progress by criticizing others, but by performing and presenting your own research.”
This is just fundamentally wrong. If someone presents a process for squaring the circle for example, the scientific method is to point out the flaws in the argument. The response that they should show how to square it themselves is absurd. Einstein’s EPR paper described a thought experiment that he considered undermined a particular understanding of quantum physics – was that also anti science progress, because he didn’t provide his own solution for the resulting paradox, nor a viable alternative explanation of QM ?
Bas:
“McIntyre has been asking for years for code of others. That implies that he understands code and can script and run it himself, but he has never presented anything. If he has done it and failed to get a hockeystick, we would have heard it.”
That is such a bizarre statement. Steve has repeatedly made his code available (while the climate scientists did not), having reconstructed their methods from their publications. It is precisely from these reconstructions he made that he could identify the crazy idiosynchacies which the original publications depended upon to generate their hockey sticks (eg flipping proxies haphazardly upside down, being dependent on only one or two signature proxies, generating chaladni patterns, using algorithms that generated hockey sticks from noise to name a few of the examples). If you want to see his code, just go back and check the earlier articles.
The other side of the coin is when the climate scientists get a non-hockey stick you can guarantee you won’t hear about it. For example, the readers of this site pointed out that the Gergis Pages2k reconstruction did not follow their described method (which had been expressly created in order to respond to criticisms here and elsewhere, an acknowledgment btw that the criticisms were valid), and when doing so their result was not a hockey stick any more. Rather than publishing a study which did not produce a hockey stick, they withdrew the paper (while other climate scientists suggested they just remove the part of the process which prevented the hockey stick occurring – you could barely make up these stories, but they are a fact).
Bas:
“You also wrote “Let’s not kid ourselves that pointing out such things as proxies being used upside down, algorithms used generating hockey sticks from noise,…”. I believe that you are now parroting what you have read on this blog. Maybe you should also look elsewhere, to find out that many of these points have been debunked. There is a reason why climate scientists aren’t convinced by his arguments and it is not because they are all in big conspiracy to ignore him.”
I have followed this debate since it started, and initially (despite having a degree in physics) had to ask questions from both sides to clarify various things. I came relatively quickly to the conclusion that most of the criticisms are valid. The points have not been “debunked” – they have in fact been verified by external parties, and are verifiable by yourself if you have a small amount of science background. Why don’t you go back through some of the earlier articles, it’s very eye opening.
None, you claim about the points that McIntyre has raised “The points have not been “debunked” – they have in fact been verified by external parties”.
Let’s briefly look in more detail at one of the claims, published in one of the few scientific papers he ever published on the matter, McIntyre and McKitrick, 2005 (or as you propose: “Why don’t you go back through some of the earlier articles, it’s very eye opening”). The ‘eye opening’ is that it has been debunked in for example Wahl and Amman, 2007, but also on the internet (https://andthentheresphysics.wordpress.com/2013/07/10/debunking-the-hockey-stick/). Basically, from what I understand, McIntyre claimed that the MBH98 algorithm would generate a hockeystick even from “ (trendless) red noise”, but the data that he used to ‘prove’ this was not noise but had a hockeystick-pattern in it after all.
Now, we could start a tit-for-tat and repeat a lot of what has been written before in social media on claims and counter-claims. Maybe you can present another publication criticizing the one I presented, and then I could pick another one. Is there any point in that? After all, the main point for me is what I wrote in my previous messages but what you ignored: “[there has been no] retraction of any of the publications on hockeysticks because of improper dataset selection of improper statistics” or “There is a reason why climate scientists aren’t convinced by his arguments and it is not because they are all in big conspiracy to ignore him.” It is clear: it is because the arguments of McIntyre (despite being revered on the internet) do not stand up to scientific scrutiny. You and I, we are just amateurs who like to argue, but the discussion has taken place and has been settled by the real experts.
Wahl and Ammann did not “debunk” a single claim of our earlier articles. Their code for emulating MBH almost exactly replicated our code and they replicated results that we had previously obtained, including our then controversial claim that verification r2 of early steps of Mann reconstruction were barely above 0. Indeed, Wahl and Ammann found that the verification r2 for the AD1600 step was 0.0002 – showing that the reconstruction was as worthless as we had observed. Wahl and Ammann confirmed the Mann hockeystick was dependent on (flawed) stripbark bristlecones as we had observed. As Wegman wryly observed, Wahl and Ammann actually was replication of McIntyre and McKitrick, not Mann et al.
And, by the way, you obviously spouted off against Paul Dennis without checking who he is. He’s not only a practising paleoclimate scientist but was on staff at University of East Anglia, the very centre of Climategate.
Nor is your understanding of other points correct.
Steve, I have to repeat myself:
“we could start a tit-for-tat and repeat a lot of what has been written before in social media on claims and counter-claims”.
“[there has been no] retraction of any of the publications on hockeysticks because of improper dataset selection of improper statistics”
“essentially all climate scientists accept [Pages2K-2019] as a scientifically sound best estimate.”
“Any research, in any field of science, has limitations and can be criticized. That doesn’t invalidate it and doesn’t mean it is poor science.”
“There is a reason why climate scientists aren’t convinced by his arguments and it is not because they are all in big conspiracy to ignore him.”
I do not want to go further into arguments on specific proxies or methods – there is no point in that since I am no expert in the matter. When I look at the big picture, I simply notice that after 20 years of criticism, the general concept of the hockeystick is still accepted by the scientific community and despite the limitations the initial conclusion is still valid: “it is clear that the current temperatures and speed of temperature increase are unprecedented in the Common Era. In the past 20 years, he [McIntyre] has not presented any credible arguments to question or invalidate that overall conclusion”.
I did not comment on the reaction of Paul Dennis. I am sure he knows much more about it than me. He is one climate scientist. One that has been close to you ever since climategate, thus not really independent in the debate. He has a point, that you can take the credit for forcing people to take a closer look at the methodologies and validity of the proxies. But I notice that his personal conclusion does not match the conclusion of most other experts in the field. As an outsider, why should I accept his conclusion and not the one of all the others?
Bas comment – “He is one climate scientist. One that has been close to you ever since climategate, thus not really independent in the debate. ”
As if the climate scientists heavily invested in defending a straight shaft using low resolution proxies are independent
“As an outsider, why should I accept his conclusion and not the one of all the others?”
About seven years ago I started to look into climate science with the same question, only “his conclusion” was that of John Christy and Judith Curry in their WSJ article that cited science I had not seen before. Both these people were highly credentialed climate scientists and IPCC authors. What made them say that CO2 might cause only a fraction of the warming that the models are claiming? I searched “skeptical climate scientists.” The top hit was a site called Skeptical Science. I soon found it wasn’t. This was my initiation in the tricky world of politicized science. I searched Judith Curry and soon learned of a law suit between climate scientist and a political satirist. Then I knew I was entering an interesting world, one through the looking glass, where data can be used upside down with impunity, high resolution data can be spliced to low resolution data of a different type and be modulated by weighting according to how well the signal fits the predetermined conclusion.
I started neutral on the topic. I was in high school when I first heard of the concern of warming. Before that I had been taught that another ice age and catastrophic cooling could be a global problem some day (but too far into the future to worry about). I remember thinking that warming did not sound so bad. I grew up in the US northeast.
Michael Mann and most of the climate scientist sounding the alarm just happen to be of the age when they would have been taught since kindergarten that human caused global warming could destroy humanity. Gas, did you ever consider that “all the others” you refer to had their conclusions indoctrinated into them as a catechism in grade school, which had been the driver that brought them into their field, not to find the answers, but to prove them by any means at their disposal, all while being showered in rose pedals by an adoring faithful and generous administrators that sought their positions for the like purpose?
Bas, I suspect Steve McIntyre is busy washing his hair and not getting back to you. But your chances would increase exponentially if you did some research. You might be surprised at what you find searching the Climate Audit archives. Suggested searches: “delete any emails”, “hide the decline.” Actually, every post is a gem. You can witness Judith Curry’s awakening, for example, mostly with the influence of Roger Pielke, Jr.
Ron Graf wrote: “Bas, I suspect Steve McIntyre is busy washing his hair and not getting back to you”
Ron, there is a hair-related Dutch saying that I think is more appropriate: “You’d better sit still while you’re being shaved”. It’s an advise for when you are in a position where you cannot counter with a proper answer, you better don’t say anything at all.
I have been looking into climate controversies on and off for years. Each time I see the same names crop up: Christy, Curry, McIntyre, Pielke, … Have you ever wondered if it is not this little group who can be accused of “politicized science”, especially when it turns out that they rarely or never publish any scientific work themselves? They muster support through blogs but (I repeat it again) “There is a reason why climate scientists aren’t convinced by [their] arguments and it is not because they are all in big conspiracy to ignore [them].”
You ask me: “did you ever consider that “all the others” you refer to had their conclusions indoctrinated into them as a catechism….”
Did you ever consider that there is a difference between doing science and sticking to a “catechism”? Do you really believe that really “all the others” -although being trained and working as scientists- are indoctrinated, unable to understand the science and unable to look beyond a perceived “catechism”? You can fool some people all the time, you can fool all the people sometime, but you cannot fool all the people all the time! So, yes, I have considered it, but concluded long time ago that there is no “catechism” that climate researches have to stick to. The criticism of McIntyre c.s. can help in further improving and finetuning the science, but overall they are unable to change the overall conclusion.
Bas, on the off chance you are still here. It looks to me that you have just gone off hunting around the net for anything that claims to refute Steve’s contributions without making any effort to understand what was done. Did you even read his original papers on the hockey stick ? Nothing that was subsequently published, for example the Wahl and Amman paper despite its claim to debunk M&M, contradicted what he had written. They got EXACTLY the same results. Why don’t you actually read both papers, and come to your own conclusion about this – if there is something you don’t understand you can always ask.
The link you posted is just a guy who clearly does not really understand the issues and is just posting stuff he has read elsewhere, and is not really sure about it. For example precisely the section you quoted:
“One explanation I have heard is that McIntyre & McKitrick did indeed produce hockey sticks from their red-noise data, but only when – by chance – their red-noise data had an underlying hockey stick”
Now, when you understand the studies, and Steve’s complaints about the hockey stick paper, you laugh a little when reading this because it’s clear whoever wrote it had no idea what was done, and it’s being repeated again by someone who had no idea what was done, and repeated again by Bas, who clearly also has no idea what was done. Let me explain this particular issue to you, it’s not very complicated, and after reading my explanation, I hope you can also understand part of the problem, and why the above quotation is ludicrous.
Let’s say you create 100 red noise sequences. Some of these will end with an upward rising end part. If you feed all 100 of these data sequences into the algorithm used by the MBH paper it will output a hockeystick. Now bear in mind that the average of all 100 red noise sequences is typically just a flat trend, but the MBH process will give you your hockey stick. From random red noise with no trend you will get a hockey stick. Now M&M went into detail on exactly why this happens, given the algorithm MBH used, so it is not even a curiosity, its explained why it happens. And yes it depends on a small number of the proxies having a sharply rising blade portion at the end. So it is funny to see the quote you posted, complaining about the red noise sequences containing a hockey stick, because someone somewhere got confused and thought that the trend of ALL the red noise sequences must have been a hockey stick, rather than it just being adequate that a very small number (as one would expect in a sample of a variety of red noise sequences).
Again I can only encourage you to actually try to understand the issues by reading the papers, rather than hunting around the net, because like you I am not interested in tit for tat responses, posting other peoples “opinions” on the details. I’d rather discuss the details.
Here’s their paper on the red noise issue btw:
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2004GL021750
It has neither been withdrawn nor refuted, because it is an accurate criticism.
squinting is a low-pass filter, but, alas not a d18O->T converter
Bas wrote “ Science doesn’t progress by criticizing others, but by performing and presenting your own research.” Just what do you think Steve McIntyre has been doing with his analysis of the statistical techniques used to construct multi-proxy studies? Research takes many forms and Steve McIntyre’s approach is but one. That he has not constructed a temperature record from the various archived proxies is irrelevant. It says more about the proxies than it does about Steve’s lack of attempt to reconstruct a temperature record. If the proxies were any good then the construction of a temperature record would be as simple as simply averaging them, selecting using a-priori criteria, with no ex-ante screening.
What we have are a series of proxies ranging from tree-rings, ice core d18O and d2H, corals (d18O, Mg/Ca), speleothems (d18O), deep sea core (foraminifera [benthic and planktonic] – d18O, Mg/Ca], carved sediments (sedimentation rate) etc., many of which are ill defined with respect to their response to temperature. Take corals as an example. The d18O of coral carbonate depends on the temperature dependent partitioning of 18O between water and calcite. The equilibrium partitioning can be determined experimentally, estimated from ab-initio calculation using known spectroscopic data for the vibrational frequencies of the associated molecules and moieties. However, we also have abundant experimental and field data that suggests that during calcification by corals 18O is fractionated under disequilibrium conditions. There is a kinetic effect that is poorly understood.
Thus in this apparently ‘simple’ system to back out temperature one needs to measure, or estimate (i) the d18O of the coral carbonate, (ii) the d18O of the host water, (iii) the extent of disequilibrium and the temperature, salinity, photic and nutrient level dependency of this.
Hence a coral d18O record is only part of the story. A d18O signal that becomes more negative as a function of time might be recording (a) an increase in temperature, (b) a decrease in water d18O value, (c) a change in any one of a number of environmental parameters that affects calcification kinetics and disequilibrium.
When the record is short, as in the examples highlighted by Steve McIntyre, one cannot simply assume that it can be spliced onto longer term proxy archives because one has no data or evidence as to how the coral d18O response varies on a longer time scale. It might well show variations in d18O value of similar magnitude in the longer term as a function of changing environment and not just temperature.
I’ve used corals as an example to illustrate the complexity of backing out temperature from just one proxy for ‘temperature’ – coral d18O. This is one of the simpler systems. I maintain that without a constitutive understanding of the proxy response that is backed up by experimental and theoretical considerations then it is not appropriate to use them in multi-proxy reconstructions. Simply observing a phenomenological correlation between proxy response – in this case d18O and local temperature, or (as has been done in the past) global temperature is not adequate if one is to robustly estimate past temperatures.
I can’t speak for Steve but suspect his views might be similar to those I express here.
To summarise, the work Steve McIntyre has done on unravelling the statistical methods used and their limitations IS research. I also know that it is highly thought of amongst many climate scientists. That many do not take on-board his criticisms says more about the state of climate science than it does about Steve. I also suggest that our present state of understanding of proxy response to temperature is limited to the extent that the existing multi-proxy studies are not, and cannot be, viewed as having any degree of robustness in terms of determining present, past temperatures and rates of variation. This comments that the present rate of temperature rise is not matched in the common era cannot be validated.
Valerie Delmotte-Masson is right. We should be putting a great deal of effort into understanding and developing the best ‘thermodynamic’ proxies such as 18O fractionation, order-disorder in isotopic distributions (clumped isotopes) etc. Progress in these areas is incredibly slow needing to be backed up by detailed theoretical work on molecular and lattice dynamics, experimentation in the laboratory and field, development of new analytical techniques and the collection of long-term proxy archives that are selected on a-priori criteria and not ex-ante screening as has been done for the ‘hockey-stick’
That went right over your head, didn’t it?
Bas wrote: “…you overestimate your own understanding, are unwilling to accept that the rest of the scientific world sees your arguments as invalid…”
David J. Verardo, the longtime program director of paleoclimate research funding for the National Science Foundation, visited Climate Audit in 2015 and posted this in regards to Steve’s work: “I have seen some of your blog’s posting as having a positive effect on scientists in the technical arena. It is too bad that some cannot bring themselves to acknowledge your help. It is wrong. In this regard, we are kindred spirits.”
It was very big of Mr. Verardo I thought to acknowledge Steve’s contributions, though it was in a very by the way manner. His real purpose for the visit was to clear any thought that his wife’s connection to her university colleague that Steve just exposed as misdirecting millions of climate research funds to his family run foundation and personal projects, including a school he founded in his hometown in India. You US tax dollars at work. As Steve pointed out, the school was likely the most productive part of the funding gusher.
Thanks again Steve for the entertainment.
It provoked me to revisit some of your older posts on the PAGES farce, especially on Quelccaya. This one https://climateaudit.org/2018/10/07/pages2k-2017-south-america-revisited/ reported on the wholesale changes the PAGES group made to their South American network between their 2013 and 2017 versions. They rejected 18 out of the 23 series they had used only four years earlier – totally invalidating their own work.
But the real killer was the reasons for rejection. In ten out of the 18 cases it was “reject – record too short – less than 300 years”. Yet only two years later they were back at it again – 6 out of 9 in your random sample are less that 300 years long, and from the look of your chart of start dates, that is typical for the whole 0-30S network.
Maybe we should just all wait for PAGES23 or 25 to throw out PAGES19?
thank you for observing this. I’d forgotten about that episode in the PAGES story. I’ll add a comment about it.
Here’s what they said in PAGES2017: they had special exemption for corals
if one watches the pea, the phrae that “shorter duration records …are importanbt for calibration-verification exercises”, it indicates that calibration-verification “exercises” fail if they only use the proxies that extend back to the medieval period – something that is visually obvious by the non-HSness of the longer proxies in this network. But if they splice on the corals – more or less painting a moustache on the long proxies – they “improve” the calibration-verification exercises. What a morass.
See the blog BomWatch for a recent analysis of sea surface temperatures from a ship survey through the Great barrier Reef by scientists in 1871. Author Bill Johnston found no significant differences between 1871 SST and modern, official ones.
If this is generally correct, how are coral series calibrated against (non-existent) variations in temperature? Geoff S
With most of South America, sub Saharan Africa, most of the continent of Australia and the islands to the north included in the study, I would expect a much more robust population of proxies. Secondly, they need to follow the proxies much further back into the past to be able to compare the present climate with know eras of the past. I would be highly embarrassed to have produced this “science” report.
Some interesting background on PAGES2k in the Swiss weekly newsmagazine Weltwoche here: https://kaltesonne.de/wer-hat-die-mittelalterliche-waermeperiode-ausradiert/, translated here: https://notrickszone.com (see under: “Who Erased The Medieval Warm Period?”).
Thanks again Steve for digging into this particular “morass”, which is not improved by the justification the PAGES team thought up for using super-short coral records, namely that they “provide critical information where instrumental data are often sparse or absent”. For if these super-short records fill gaps in instrumental data, how can instrumental data verify or calibrate them?
One Team answer to this in the past has been to verify proxies against the global temperature record, not local temperatures. But of course this is circular reasoning. It means using the hockey stick in the instrumental record to select proxies that also have a hockey stick, but considering those proxies verified because they match the hockey stick in the instrumental record.
Behind all the illogical bobbing and weaving are some stubborn facts. Long-term proxies don’t show a hockey-stick blade, so either the blade doesn’t exist or they are not reliable proxies; in either case, composite graphs with both long-term proxies and a hockey stick are unreliable. Many of the proxies used have been recognised for decades as more representative of precipitation than temperature, on both a priori and empirical grounds. Verification demands correlation of local proxies with local instrumental records, not correlation between local proxies and global mean surface temperature. Hundreds of studies, going back decades, still indicate that, despite recent warming, many parts of the world have not even reached the peak temperatures of the medieval warm period, let alone the higher peaks 3000-8000 years ago.
David Brewer – I need some clarification on your comment. Are you stating that the long term proxies show a straight shaft and no HS blade. Are there any long term proxies that have a straight shaft with a HS blade?
thanks for any insight.
joe, you ask “Are you stating that the long term proxies show a straight shaft and no HS blade?”
In this case there are only two long-term proxies, taking these as proxies that go back at least to the medieval warm period. They are Makassar and Quelccaya, shown above. It’s true that there is a bit of an uptick in both of them towards the end, so if you look hard you might see slight sticks. However, their “blades” would both start about 1750, not in the 20th century, and their final values around the year 2000 do not exceed numerous peaks hundreds of years ago. So, to be precise, what I would say is that, at least in this case, the long-term proxies do not show hockey sticks of the Mann/PAGES variety, and do not bear out the claim that temperatures shot up in the 20th century to values exceeding any in the past 2 millennia.
Are you stating that the long term proxies show a straight shaft and no HS blade?
The two selected long term proxies have the straight shafts. There could be many omitted long term proxies that do not have the straight shafts. They could have MWPs, or other non-straight appearing line segments.
Some of these omitted long term proxies could also have recent “HS blades.” But they would still be problematic because they lack straight shafts. They would be thrown out.
Most focus is on examining omitted recent proxies that conflict with the blade. There is much less about examining long term proxies and whether they conflict with the straight shaft. I suspect there are some, maybe more.
Good point, Follow the Money. As a general rule, the worse the proxies, and the more of them there are, the straighter the blade will be through ancient, medieval and early modern times. With bad selection methods, and poor data treatment, and hundreds of series, the most likely result is white noise, and not even very noisy, i.e. a straight, flat stick. This has been the result, and it seems the intention, of PAGES and similar exercises over the last 20-odd years – to blot out decades of earlier and more honest research that had identified the medieval and Roman warm periods.
You might not be a climate scientist, but you certainly display the arrogance of one.
That was meant to be under Bas’s comments, not sure why it ended up at the bottom of the thread.
Steve, I think Bas is disappointed in you for not being prescient enough — that disqualifies you as a climate scientist — of not being able to invalidate conclusions from last 40 years of data 20 years ago.
In fact, it’s pretty straightforward: good proxies don’t have blades.
Bas said “Science doesn’t progress by criticizing others, but by performing and presenting your own research.”
Bas, I suggest googling this: NOVA What Makes Science True?
It is no longer astounding to me, how many people have no idea what science is. No, “consensus” is not science.
As noted by several, science is ALL about critiquing previous work. We put up hypotheses, and then work incredibly hard to tear them down.
Finally, it sure is good to see you back in the saddle, Steve 🙂
MrPete, when I google that, I find something about the importance of being able to reproduce results in life sciences (not climate science).
I just want to remind you of something I wrote here a few days ago: “He [McIntyre] has never shown assembled proxies himself and combined them in his own graph” In other words: McIntyre has never tried himself to reproduce the research on assembling proxies, by defining his own (better) selection of proxies, writing his own code and obtaining his own graphs. If he had done so, he would have been able to either confirm that work, or to demonstrate that the hockeystick is flawed. So basically, you state that what McIntyre does, is not science, because he has not tried to reproduce!
But there are other research groups who have done so: using their own strategy for selecting proxies, writing own code and getting independent results. The results are slightly different from the initial hockeystick but the overall picture remains the same: a handle with gradual changes and a blade with a sudden, pronounced increase. They have confirmed that the initial work is reproducible.
“As noted by several, science is ALL about critiquing previous work.” Science is NOT ONLY about critiquing previous work. We only make progress when people also actively contribute by presenting better analyses.
“But there are other research groups who have done so”
These are very creative people and I have no doubt that they are able to paint the enigmatic smile of Mona Lisa from the same datasets.
To be serious, essentially temperature-sensitive datasets are not shaped like a hockey stick. We have to deal with it and ask ourselves the real question: why this divergence between proxies and instrumental indices.
Bas – Just because numerous studies reach the same conclusion doesnt make that conclusion valid / true.
I use the ground level ozone studies as a prime example, the Bell / mcdermott study being one that is considered the gold standard. The conclusion is that increases in ground level ozone cause increase in pre mature mortality. The error in the Bell McDermott study is that several cities have negative correlations to increases in ground level ozone (contradictory data) , their is bias in the data (poor data) collection and another factor that has near 100% correlation that is ignored.
All the HS studies which reach the consensus HS conclusion have similar defects. contradictory proxies which are ignored, bias in the data selection (ex post screening and low resolution proxies), bad statistical analysis, similar to ignoring factors in the ozone which has near 100% correlation. Use of proxies which are poorly calibrated to actual temps, etc.
The climate scientists repetitive use of poor proxies is ignoring the critisism, It doesnt qualify as debunking the critizism. There remains far too many proxies used that do not reconcile to other known events.
Joe “All the HS studies which reach the consensus HS conclusion have similar defects”
There have been blogs etc on these perceived defects for 20 years. But my question remains unanswered: why has there not been a single retraction of any of the publications on hockeysticks because of improper dataset selection of improper statistics? And why hasn’t McIntyre, another blogger or anybody else never published a paper without these perceived defects?
Bas’s comment – “Joe “All the HS studies which reach the consensus HS conclusion have similar defects”
There have been blogs etc on these perceived defects for 20 years. But my question remains unanswered: why has there not been a single retraction of any of the publications on hockeysticks because of improper dataset selection of improper statistics? And why hasn’t McIntyre, another blogger or anybody else never published a paper without these perceived defects?”
As you ask – Why havent those HS studies been retracted or why has anyone else published a paper without those defects?
I refer back to the Ground level ozone studies – to a large degree it is because of political pressures and group think. Who wants to publish a paper stating that ground level ozone is not a health hazard? Who is going to fund such a study. (fwiw, In my opinion, ground level ozone may be a health hazard, but the studies showing an increase in prematurity mortality are deeply flawed).
Bas asks: “…why has there not been a single retraction of any of the publications on hockeysticks because of improper dataset selection of improper statistics?”
Who told you there hasn’t been? As a result of a Climate Audit blog Gergis el al (2012) was withdrawn by the authors at the insistence of the Journal of Climate (essentially retracted). This was before my time, but it went something like this: McIntyre pointed out that Gergis was manufacturing a hockey stick by selection. This “screening fallacy” was famously demonstrated by MM05 whereby red noise could make a hockey stick. Gergis responded to the Climate Audit criticism by claiming that her code mitigated this effect by using detrending. After Steve published a link to their code a commenter named Jean S noticed that the code was not detrending the data. Uh Oh. So the lead author, Gergis, emailed Mike Mann and asked if that was still OK. He said sure; that’s the way he always did it. But the journal did not buy it (to their credit).
You can search “Gergis” in the search box above. I came to this nice quote from a 2012 post by Steve:
Remember, by this time the world heard the broadcast the paper’s press release but never heard about its withdrawal.
‘1000 years of Australia climate data confirms “unprecedented” warming.’
Ron Graf, thanks for this info on the retraction of Gergis2012 – I wasn’t aware of that.
This basically shows that if you have valid criticism, a paper will get retracted. In a way this only strengthens my point of few: the retraction-system works and none of the others have been retracted, so it appears that the criticism on the others aren’t valid.
I can now rephrase one of my two questions: “why has there only been a single retraction of any of the publications on hockeysticks? And why hasn’t McIntyre, another blogger or anybody else never published a paper without these perceived defects?”
“In a way this only strengthens my point of view: the retraction-system works and none of the others have been retracted, so it appears that the criticism on the others aren’t valid.”
When information confirms one’s theory regardless this means that one’s test had one or more logical fallacies. In this case one of them was the assumption that Climate Audit and skeptics lacked productive impacts, (likely because they are acknowledged very quietly by the climate scientific community at large). I don’t blame you. I was in your shoes 7 years ago and found I had to do my own research to find how supplied the truth and why it is commonly distorted in today’s media. I sincerely encourage you to read both sides of the climate issue while remembering it is not an even contest. One side has all the money and power. I don’t get a check from “big oil” and I would be surprised if anyone else with a skeptical voice was either, despite the talking points of the climate justice community. Also, skeptics are not all conservatives (I found to my surprise). And conservatives are conservation minded as much as liberals, and maybe even more concerned about the future. There are many hazards, including being tricked into surrendering freedom.
On one hand we will have milder Canadian winters, better crop yields, more fresh water; on the other, possibly also accelerated sea level rise. Perhaps we just focus on the bad one directly. Everyone is for solutions using technology advancement. I hope this has built a bit of trust and you can pass it forward. Cheers.
Bas,
“In a way this only strengthens my point of few: the retraction-system works and none of the others have been retracted, so it appears that the criticism on the others aren’t valid.”
If Gergis’ paper was withdrawn, it is because she falsely claimed to use a suitable method (selection on the basis of detrended series). The other papers which obtain a form of hockey stick do not claim to use a suitable method. They have therefore not been retracted.
Contrary to what you think, this episode clearly demonstrated the validity of Stephen McIntyre’s critiques.
Ron Graf wrote to me: “I was in your shoes 7 years ago”
I doubt it. I have been in discussions on and off for 25 years with outsiders who claim to know it better than experts: ‘vaccines cause autism’, ‘evolution by Intelligent design’, ‘9/11 is an inside job’, ‘there is no antropogenic global warming’, … They all started their “own research to find out how distorted the truth is”. They all believe that “one side has all the money and power”. They all believe they fight an uneven battle, but that they know best.
But I also learned: none of them have ever got the same depth and breadth of knowledge as the real experts. They simply believe they understand it all and are convinced they know it better than established science. Their viewpoint ranges from ‘the scientists are misguided/stuck in fixed ideas’ to ‘it’s all a big conspiracy. They all started with a conviction and everything their years of “own research” achieved was cherrypicking and a confirmation bias of that conviction. They stick to their viewpoint but refuse (or are unable to) address questions that are not compatible with that conviction. They like to argue about one specific point an believe that if they get a perceived win in that discussion, it proves that there entire conviction is confirmed. (as in: ‘if we can prove MBH98 is incorrect, then all hockeysticks are incorrect and/or all climategchange is incorrect’).
I admit: climateaudit is one of the milder ones (unlike some of its followers here). McIntyre appears to be more knowledgeable than most ‘sceptics’ and has made valid points in the past. I don’t think he believes in a ‘conspiracy’, he just believes to know it better. He critizises but is not able to positively contribute by presenting his own ensembles. During 20 years, the evidence for a hockeystick has continued to accumulate in many publications through different proxy-selections and different methodologies, but he has not been able to present sufficiently credible arguments for the scientific community to reject the hockeystick. But as long as he continues blogging about it, he will have followers who believe that he is ‘on the right side’ and that any hockeystick is poor science or even scientific fraud.
He is also very coy about what he does accept. He criticises but I have found nowhere what he accept as valid studies. It is for example not clear to me if he accept that the current warming is due to greenhouse gas emissions. To be fair, he does not have to state that, but he doesn’t seem to have a problem that his work is used and abused by climatechange deniers. It is typical of what I learned about self-declared ‘sceptics’: they keep quiet about what they know is true but doesn’t really fit their conviction.
I admit I am not an expert on paleoclimate. But even after 7 years ofreading blogs and some papers, I would not become one (and neither have you – admit it). I am a scientist however. I can understand most of what is presented in these papers, but it is the final 10% of the understanding that differentiates between an ‘enthusiast’ and a real scientist. My conclusion on these papers will never be as thorough as that by climate scientists. I observe that they don’t doubt the overall pattern of the hockeystick. So why should I not believe them? Because they are all incompetent of are all part of a conspiracy?
Bas, you bring up the issue of consensus rightly. Also, Mr. Pete rightly says, “No, “consensus” is not science.” Consensus is the first tool used by any social group or society for truth. Customs, fashion and religions are still governed by it exclusively. Science was a historic break from truth deriving solely by associations and consensus enforcement. Scientific truths are validated by reproducibility, logical fit with all other validated science and the ability to make predictions that otherwise could not be made. All of these leave a scientific truth vulnerable to falsifiability. The testing of predictions is usually carried out by statistical analysis of data collected measuring the postulated effect. If this testing is shown to be faulty, whether by another scientist or lay person, the validation is worthless. And if the results had been published a retraction or corrigendum would be called for. There is no scientific burden placed upon Stephen McIntyre to create his own reproduction in order to reveal falsifications in MBH98 or any other scientific paper. Of course, the public at large (including scientists) still rely heavily on consensus for their beliefs. And nothing stops scientists or others from working the refs, including children.
By the way, McIntyre has engaged in field work, including expeditions collecting tree ring cores. He has created reconstructions. Using Mann’s code he and Ross McKitrick were able to reproduce the hockey stick using red noise. https://climateaudit.org/2005/03/11/mm05-chosen-as-a-grl-journal-highlight/
“Bas, you bring up the issue of consensus rightly”
No, I did not mention “consensus”. I only pointed out that others independently got the same results and that no paleoclimatologists ever obtained a graph that was not a hockeystick. You just got stuck into the standard mantra about “consensus”, as found on pseudosceptical blogs. BTW, consensus is part of science: it presents an overview of what is known and not know. It doesn’t claim any ‘truth’, but usually the evidence is so overwhelming that it is generally accepted as true. There is scientific consensus that there was a Big Bang, that evolution takes place by natural selection, that vaccination does not cause autism, that black holes exist,… and that the current warming is unprecedented and caused by greenhouse gases.
You refer to the article of McIntyre & McKitrick 2005. You seem to have missed my post of Sep 7, 2021 at 12:10 PM: that article was flawed.
Meanwhile, I am still waiting for anybody to present good science that shows that the rapid rise of 0,8°C in the past 40 years is not unprecedented. All the research showed that temperature in the Common Era changed gradually and less than 0,5°C.
Bas – You mentioned that most all climate studies have reached the same conclusion and therefore should be accepted.
I point to the following as a comparison. The medical scientific community all agree that ground level ozone is responsible for an increase in premature mortality. Virtually all peer review studies reach this conclusion. The Bell /Mcdermott study of 96 US cities is considered the gold standard. Yet that study, like most of the others suffers from numerous errors, including poor and bias data collection, negative correlations in several cities, ignoring factors/causes with much higher correlations. In these studies, increase in ground level ozone only has a 60%-70% correlation, while another factor has near 100% correlation.
I mention the ground level ozone studies because the parallels of the deficiencies in the HS studies are remarkably similar. Most all the climate reconstructions reach the same HS conclusion. The Pages2K studies are likewise considered the Gold Standard. My observation is that these studies suffer from similar deficiencies that are repetitively ignored, including but not limited to utilization of poor / low resolution proxies, poor use of statistical analysis, ignoring conflicting data.
Your last comment regarding unprecedented warming – ” Meanwhile, I am still waiting for anybody to present good science that shows that the rapid rise of 0,8°C in the past 40 years is not unprecedented”
The question I present to you – Do you (or any climate scientist) believe the resolution of the proxy temperature data is even remotely high enough to ascertain the validity of that conclusion?
Bas replied: ‘No, I did not mention “consensus”. I only pointed out that others independently got the same results…’
Even if you did not use the word consensus you were invoking its concept and misunderstanding its role. Consensus is an unavoidable requirement. All truths are effectively defined by the group’s acceptance of them. The problem before scientific reasoning was that any association could be made about anything and be accepted as truth without further scrutiny as long as the sociological power dynamic that put that belief in place remained. The scientific method did not replace consensus; it added new hurdles to it and supplied a ripcord in which consensus could be overturned by a single individual. David Verardo seemed to recognize this and lamented that climate science was hindered by resisting McIntyre’s contributions.
Modern science exists within sociological power dynamics that still remain. Human nature has not changed. Science proceeds headwinds in politically significant areas. It would be ideal if all sides agreed that scientific standards needed to be heightened in these areas, debate enhanced, rather than cut off, shouted down or cancelled.
@Joe & Ron Graf
You basically both claim that any criticism has been ignored or hindered. What makes you conclude that? Were critics ever blocked from accessing conferences or from publishing ensembles without a blade? To me it rather looks as if the criticisms have been looked at, some of it has been accepted but most has been found to be not valid criticism.
Joe: I am not familiar with what you write, but even if it is true that there is a problem with the ozone-studies, that is no evidence whatsoever that there would be a problem in climate research. It is the fallacy of the false analogy.
To answer your question on the validity: the hockeystick has a region of uncertainty around it.
Ron Graf: I suggest you read all the posts of Verardo in the link you gave earlier. He also wrote “I stick by my view from 2003 that the evolving understanding of climate will eventually inform us.” And “I think the jury is out on how effective the blogosphere is in terms of helping to build a society of informed and engaged persons.” I observe that 20 year of blogging may have helped to paleoclimate research a bit in being more alert to scrutiny, but has fundamentally not changed the overall scientific conclusion.
Bas, Verardo was/is the manager for Mann’s hockey team for ~23+ years. He did a Climate audit drive by not to thank Steve for uncovering millions of dollars in fraud at the hands of Shukla’s NSF connections, he was just trying to keep his name and his wife’s out of it. Think about his position to Steve. He had seen him testify in congressional inquiries attacking his funded clients (Mann et al). Just like Fauci was sensitive to WIV’s plight due to his funding of their making novel SARS viruses that could cause a pandemic Verardo was sensitive to his hockey team being exposed doing less than wholesome science, not that Verardo or Fauci are personally accountable for their grantees deeds.
The climategate emails revealed the exact wrong doing that you claim never happened. Mann and company were up to blocking publications of adversarial work, making false smears and other shenanigans. All his power and swagger came from the financial and political backing of the NSF, EPA, NASA, NAOAA, Democrat Party and countless green groups. Steve has this blog – integrity and the truth.
Bas, your theory that all the paleoclimate reconstructions are hockey sticks is countered by the last four blog posts. Most of the long proxies are just shafts. It wasn’t until Mann’s ingenuity that showed the way for others that they could graft a blade onto them. Reconstructions before the AGW craze showed a Medieval Warming Period, Little Ice Age and recovery, not a hockey stick, according to old timers. I think they have all been erased.
Bas, Verardo was/is the manager for Mann’s team for ~23+ years. He did a Climate audit drive by not to thank Steve for uncovering millions of dollars mishandled at the hands of the Shukla’s and their NSF connections, he was just trying to keep his name out of it. Think about his position to Steve. He had seen him testify in congressional inquiries attacking his funded clients (Mann et al). Just like Fauci was sensitive to WIV’s plight due to his funding of their making novel SARS viruses that could cause a pandemic Verardo was sensitive to his hockey team being exposed doing less than wholesome science, not that Verardo or Fauci are accountable for their grantees work.
The climategate emails revealed the exact wrong doing that you claim never happened. Mann and company were up to blocking publications of adversarial work, making smears and other shenanigans. All his power and swagger came from the financial and political backing of the NSF, EPA, NASA, NAOAA, Democrat Party and countless green groups. Steve has this blog – integrity and the truth.
Bas, your theory that all the paleoclimate reconstructions are hockey sticks is countered by the last four blog posts. Most of the long proxies are just shafts. It wasn’t until Mann’s ingenuity that showed the way for others that they could graft a blade onto them. Reconstructions before the AGW craze showed a Medieval Warming Period, Little Ice Age and recovery, according to old timers. I have not seen these but I believe they exist somewhere.
Ron Graf,
Insisting that the comment of Verado is important, is the logical fallacy of the argument from authority. Moreover, you are rather selective about what you are willing to accept from his statements.
“the financial and political backing of the NSF, EPA, NASA, NAOAA, Democrat Party and countless green groups” Yep, it’s all one big conspiracy, lol!
“I have not seen these but I believe they exist somewhere.” Do you think that will convince me?
Bas wrote: “The point is that these series vary by 0,5°C or so at timescales of centuries, whereas it has increased by 0,8°C in the most recent 40 years.”
Bas, I have a somewhat different perspective that may be of some help. (If I have made any mistakes, I hope someone will correct them.)
Unfortunately, the 0.8 degC warming over the last 40 years you cite was measured with thermometers. To quantify natural (unforced) variability in climate we must “reconstruct” temperature over the past one or two millennia from proxy data. (The thermometer record already shows significant natural variability in one century: there was a period of unusual warming in 1930-45, coolness from 1950-1975 and a “Pause” in warming for more than a decade in the 2000’s.) We learned from experiments where noise was added to artificial proxy data that too much noise in proxy data leads to reconstructions where temperature changes like the LIA or MWP are lost in a noisy “stick”. We don’t know how much of the variability in proxy data is due to temperature signal, how much is due to other climate signals like precipitation, and how much is due to noise. To prove that your 0.8 degC of warming is unprecedented in the past two millennia or longer, climate scientists would need to prove that they can reconstruct that 0.8 degC of warming we have seen in the thermometer record and compare it to natural variability during the LIA and MWP. This is why Steve keeps complaining about the lack of proxy data which covers both the MWP and the current warm period. Reproducing twentieth century warming from one kind of proxy data doesn’t validate a reconstruction make mostly from different proxy data!
Unfortunately for Mann and others, they were attempting to do this in the late 1990’s and 2000’s, when we had experienced only 0.4 degC of warming over the past roughly two decades. Even worse, few proxy records even reached into the 1990’s and many ended much earlier. So, the best that many proxies could do was reconstruct the 0.2 degC of warming after the slight cooling from 1950-1975 ended and the warming in the 1930’s (little of which was caused by rising GHGs). When a 10- or 20-year smooth is applied to a reconstruction, even more warming would have been lost without “Mike’s trick” of adding data so the smoothed curve could extend to the end of the proxy data. To complicate matters, some tree ring series exhibited a “divergence problem” and didn’t exhibit wider rings in the second half of the twentieth century. Nevertheless, it was imperative for political reasons for climate scientists to prove that current temperatures were warmer than during the MWP. Based on the work of Mann and others that was challenged here at Climate Audit, the SPM’s for AR3 and AR4 both asserted that it was “likely” that current temperatures were warmer than during the MWP. “Likely” meant greater than a 66% likelihood, but the hockey stick reconstructions of Mann and others claimed much greater certainty. However, there were doubts about Mann’s first reconstructions because they failed to even show a clear LIA, perhaps accounting for the “likely” qualifier.
With 20/20 hindsight, given these difficulties, Mann and his colleagues were on a hopeless quest (IMO). Yes, they could cherry-pick proxy records, develop ad hoc methods for analyzing that data, publish positive results and make politically useful conclusions in AR3 and AR4, but that process ended in abstracting a warming signal from red noise, an eight-standard deviation tree ring from the “most influential tree in the world”, and the Climategate scandal. From my perspective, it didn’t matter one bit if temperatures in 1980 failed to exceed that of the MWP. With projected warming of about 0.3 degC/decade and observed warming of about 0.2 degC/decade, if 1980 wasn’t warmer than the peak of the MWP, then 1990 or 2000 or 2010 or 2020 would be. What did matter to me was the corruption of science.
IMO, Steve McIntyre won the debate even though many hockey stick reconstructions were never retracted by their authors or journal editors (as Gergis was). The AR5 SPM stopped claiming that “current” temperature (at an unspecified date) was warmer than during the MWP. Instead it said that the MWP was not a period of simultaneous warming over most of the planet similar to the one we are currently experiencing. And the AR6 SPM doesn’t make any such claim either. Figure SPM.1 and Box TS.2 show instrumental and reconstructed temperatures, but still doesn’t clearly show how much of the observed current warming can be reconstructed from proxy data. Chapter 2 Box 2.1 shows important paleoclimate reference periods, omitting BOTH the MWP and LIA from the last millennium. (AOGCMs show little cooling associated with the known forcing during this period, so both the MWP and LIA appear to be disappearing from the record.) They do mention the Mid-Holocene (formerly the Holocene Climate Optimum or HCO), which is interesting because ocean sediment cores generally show cooling from then until present. Since the northern tree line was much further north than it is today, we can be sure that the HCO was much warmer than today (in the Arctic summer at least), but the polar bears and Greenland Ice Sheet both survived for several millennia that were warmer than today. (:))
Frank, you give a nice summary of how certain parts of the blogosphere see the reconstruction of the hockeystick: it’s hopeless but Mann and co continue with misguided research… The reality is that there are many paleoclimatologists, they were from day one very aware that a proxy is not easy to convert into a temperature profile, so they went to great lengths to ensure that their conversion methods were valid. They also realized that the importance of selecting the right proxies and the fact that there is geofraphic hetereogeneity. They have over the years used different improvements in their methodologies and got more reliable estimates all the time. Still, it’s so easy to just disregard all that research and simply write that it is simpley “cherrypicking” or that “We don’t know how much of the variability in proxy data is due to temperature signal, how much is due to other climate signals like precipitation, and how much is due to noise”.
We can observe that in 20 years no paleoclimatologist, reviewer, statistician or other scientist has come out and said “hey guys, what they are doing is actually stupid and cherrypicking, and the bloggers are right”. This implies IMHO that the paleoclimatologists’ work is solidly grounded in science. Getting research grants is a competitive world and if grants would be going to unsound research, we would have heard a howl of other scientists a long time ago!
BTW, you write “The AR5 SPM stopped claiming that “current” temperature (at an unspecified date) was warmer than during the MWP … And the AR6 SPM doesn’t make any such claim either. ” Figure 1 of AR6 SPM states “Warming is unprecedented in more than 2000 years”, so they still claim it (and this claim is based on a scientifically sound hockeystick). In AR6 itself it says: “The terms “Little Ice Age” and “Medieval Warm Period” (or “Medieval Climate Anomaly”) are not used extensively in this report because the timing of these episodes is not well defined and varies regionally.”
We can observe that in 20 years no paleoclimatologist, reviewer, statistician or other scientist has come out and said “hey guys, what they are doing is actually stupid and cherrypicking, and the bloggers are right”. This implies IMHO that the paleoclimatologists’ work is solidly grounded in science. Getting research grants is a competitive world and if grants would be going to unsound research, we would have heard a howl of other scientists a long time ago!
This premise of this statement is probably not correct, but let’s just assume it is correct.
If this is the basis on which you choose to understand and accept temperature reconstructions, that is certainly your right. However, it is a profoundly unscientific mode of thinking. In the parlance of the day, it is “anti-science”.
I prefer to read the papers itself. But if I don’t understand it a 100% (and I am not a paleoclimatologist). I prefer to rely on the entire scientific community rather than a single blogger. Is there anything wrong with that? Why would that be “anti-science”?
Bas, there is nothing “wrong” with it. You have the right to think, believe and speak as you like. However, you’ve come to a blog where people discuss evidence and methods, and you try to persuade them to believe something because a number of other people believe it (agumentum ad populum). Not just any people, of course, but some very special people (argumentum ad hominem). “Science” does not confer authority upon any individual or institution.
“Science” proceeds from skepticism, and a scientific thinker should be skeptical of the institutional momentum that has gathered around climate studies. A scientific thinker should be sympathetic to outsiders who are poking around the edges of widely accepted belief.
Nothing about this post would be even slightly controversial were it not for the widespread belief that skeptics are preventing the required societal response to an immanent climate catastrophe.
rnwj, I agree with “A scientific thinker should be sympathetic to outsiders who are poking around the edges of widely accepted belief”. This is however not relevant here: the hockeystick is not a “widely accepted belief” but the result of scientific studies. I have the impression that it are the “outsiders” who have a “belief”: they are convinced that there is something wrong. I also observe that they have less breadth of knowledge of the subject and therefore remain outsiders. So they simply are less credible.
I don’t understand 100% the arguments on either side, but my money is on the entire scientific community rather than the “outsiders”. That is not because I want to meet a “societal response”, but because -as I wrote in another comment- “We can observe that in 20 years no paleoclimatologist, reviewer, statistician or other scientist has come out and said “hey guys, what the paleoclimatologists are doing is actually stupid and cherrypicking, and the bloggers are right”. This implies IMHO that the paleoclimatologists’ work is solidly grounded in science.”
Bas,
You write about using “different improvements in their methodologies and got more reliable estimates all the time”.
“Reliable” has developed a social meaning alongside its scientific meaning. It the social sense, reliable can even mean unchallenged in the literature; in the science sense it usually means reproducible within its expressed uncertainty terms. In the last few decades, the social use has almost submerged the science sense, as shown by the large numbers of peer-reviewed climate papers with either no proper estimate of uncertainty, or with estimates that are easily shown to be unrealistically optimistic.
Your assertion that “The point is that these series vary by or so at timescales of centuries, whereas it has increased by 0.8 ° C in the most recent 40 years” is a social statement. The claimed 0.5 ° C variability is not scientific, because there is no available measurement data on which to calculate its value, as in no temperature data in earlier centuries. With no hard data, resort is made to proxies. These have an error term from the relation between temperature and the proxy response, as it is impossible to calculate the error because historic conditions cannot be replicated, like the tree growing its its environment. The reproducibility of tree ring sampling, for example, is poor enough from one tree to the next for the method to be highly questionable. Certainly, any claim that a derived proxy temperature is better than (say) +/- 5 ° C is a social construct designed to fool the masses.
Even in the instrumented era, errors are optimistically reported. To illustrate, all relevant official bodies in Australia seem to have endorsed that heatwaves are getting hotter, longer and more frequent. In summary form, here is a quick example of how hot were the hottest 40 past 5-day heatwaves in each year in Sydney and Melbourne, home to half our population.
http://www.geoffstuff.com/sydmel5.docx
The bigger study is here –
http://www.geoffstuff.com/hw6capsjuly2021.docx
It is clear even by eyeball that these heatwaves have not become hotter over the last 150 years or so, yet the official myth has become fodder for creating panic among school children. We have done other studies in which we can see but 0.5 ° C of warming in the Australian instrumental record over the last century, as opposed to the official 1.44 ° C over the same period.
In effect, you are comparing your 0.5 and 0.8 numbers as if they had no uncertainty, when on closer study there is a huge uncertainty in each.
BTW, I sent the heatwave numbers to our BOM, who curate the official record. They responded that they could not look at data unless it was published in a peer-reviewed scientific paper. Now, my idea of a scientific paper extends way beyond content that is no more complex than addition and subtraction of provided numbers Science benefits from a new understanding of a current paradigm, preferably at a high level of comprehension. But your comments indicate that you might not have that property. Geoff S
Bas –
First – I would like to apologize if it seems like all the commentators are circling the wagons to attack your comments. Advocacy websites such as Skeptical science vigorously attack any commentator that points out errors in the science or questions any aspect of climate. I hope its not the case here.
I acknowledge that almost every climate reconstruction has reached the same conclusion using the same or similar bundle of proxies. So I think your question is a legitimate question.
I refer back to my comment regarding the ground level ozone studies and premature mortality. The key being the underlying data and the interpretation of that data. In the Bell McDermott study, ground level ozone has approx 60%-70% correlation while increase in heat has near 100% correlation. Similar issues with a study with 10 cities in France during the heat wave of 2003. In that study, ground level ozone has less than a 50% correlation, while heat had a near 100% correlation. In fact 5 of the 10 cities showed no increase in ground level ozone, yet reached the conclusion that increases in ground level ozone was the primary factor in the premature mortality. (note that the death rate in all 10 cities was near identical).
My perception is that climate scientists are following the same playbook. The parallel’s are striking.
There are two issues with the long term proxies A) the resolution of the data is way too low to determine temperature with any reasonable degree of accuracy and B) The estimated temps derived from the proxies often conflict with other documented and well known data, such as conflicting tree line elevations, receding glaciers revealing tree stumps, etc.
I hope that I am not coming across as ganging up, just noting that the reconstructions studies have not overcome the hurdle
Geoff, have a look at this: https://www.nature.com/articles/s41467-020-16970-7. IN figure 3, NAU is Northern Austeralia. Here is see a clear trend in increasing heatwaves. You don’t give any context on what is shown in your docx, wherease the paper I present gives details on how the data was gathered. Why should I accept your version, rather than this paper?
Bas
One of the most frustrating issues in climate science is the proliferation of cherry picking data. Both sides are guilty.
The starting point of the study in Nature is the 1950’s conveniently omitting the 1920’s & 1930’s
The omission of the early part of the 20th century is a little circumspect.
The climate scientists are doing what they are claiming the denialists are doing!
Bas Posted Sep 15, 2021 at 12:05 PM | Permalink wrote –
“Geoff, have a look at this: https://www.nature.com/articles/s41467-020-16970-7. IN figure 3, NAU is Northern Austeralia. Here is see a clear trend in increasing heatwaves. You don’t give any context on what is shown in your docx, wherease the paper I present gives details on how the data was gathered. Why should I accept your version, rather than this paper?”
…………
Bas,
1. In the second link I provided, there is explicit, adequate detail of the methodology I used, so I do not know what you mean by “You don’t give any context…”
2. Why should I read yet another paper from Sarah Perkins, one I have already read? She is lead author in one of the references in my second link. You cannot delve into climate studies in Australia without encountering her name as one of the leading alarmists.
3. Why should you believe my work above hers? Simple, because my work as shown in the link has very little scope for subjective interpretation. It takes official data from the BOM and sorts it into graphs. There is no cherry picking, no adjustment, no redefinition of terms. The Perkins paper has a lot of selective argument, with creation of complex indices to represent a heat wave with the result that a trend is found from her massaged data that does not exist in the raw data. If a pattern does not exist in simple data, why nor say so and avoid the embarrassment of a complex paper that tries to dispute the obvious?
…………..
Bas, you have demonstrated a strange motivation that you need to clarify. It is time for you to emerge from behind your alias, to reveal your true identity, experience and qualifications. Some comments on what motivated you to post here would also help your credentials, which are in tatters now.
Geoff S
“The reality is that there are many paleoclimatologists, they were from day one very aware that a proxy is not easy to convert into a temperature profile, so they went to great lengths to ensure that their conversion methods were valid. They also realized that the importance of selecting the right proxies and the fact that there is geofraphic hetereogeneity. They have over the years used different improvements in their methodologies and got more reliable estimates all the time. ”
On what basis do you say that “they went to great lengths to ensure that their conversion methods were valid.” I’m knowledgeable of the field and am unaware of such steps.
You also say” ” They have over the years used different improvements in their methodologies and got more reliable estimates all the time.” I’m familiar with the various studies and see no improvements in methodology or that estimates are “more reliable”. What is basis of your assertion? Other than arm-waving?
Bas wrote: “you give a nice summary of how certain parts of the blogosphere see the reconstruction of the hockeystick: It’s hopeless but Mann and co continue with misguided research…
When temperature reconstructions were begun, attribution hadn’t divided the blade of hockey sticks into forced – and possibly unprecedented – warming before mid-century, and mostly unforced – and likely precedented – warming before mid-century. Only today, with 20/20 hindsight, can I see the Mann’s proxy record likely only had 0.2 degC of forced warming.
Bas wrote: “The reality is that there are many paleoclimatologists, they were from day one very aware that a proxy is not easy to convert into a temperature profile, so they went to great lengths to ensure that their conversion methods were valid.”
According to some Climategate emails, the imperative was to find some way to negate a poorly sourced figure in an early IPCC report that showed that the MWP was warmer than the current WP. That turns out to be so easy to do – by cherry-picking proxy records with a hockeystick shape – that it has been done more than a dozen times. This was a political imperative, not a search for scientific truth. From a paleoclimatologist’s perspective, it is absolutely clear that tree rings in some locations do a good job in reconstructing temperatures in the thermometer period and others IN EQUALLY PROMISING locations do not. (Promising locations are typically at high latitudes or elevations where temperature is expected to limit growth.) Locations where tree rings “diverged” and got smaller in the second half of the twentieth century) clearly must be excluded from a reconstruction, and as many with hockey stick shapes must be included. Otherwise your reconstruction won’t show unprecedented warming by the late 20th century and you would have an unpublishable negative result. Consequently, many groups chose to include and exclude the same sets of proxies (Ie cherry-pick). Statisticians correctly find such cherry-picking appalling; paleoclimatologists find it ESSENTAL to creating a reconstruction that agrees with the instrumental record!. Steve has shown that several commonly used proxies and reconstruction methods are deeply flawed. (In 2005, Ioannidis became famous for exposing some common statistical problems in medical studies in “Why Most Published Research is Wrong”. In a publish-or-perish world, being sloppy about statistics can pay off.)
See: https://climateaudit.org/2006/03/07/darrigo-making-cherry-pie/
Bas wrote: “We can observe that in 20 years no paleoclimatologist, reviewer, statistician or other scientist has come out and said “hey guys, what they are doing is actually stupid and cherrypicking, and the bloggers are right”. This implies IMHO that the paleoclimatologists’ work is solidly grounded in science. Getting research grants is a competitive world and if grants would be going to unsound research, we would have heard a howl of other scientists a long time ago!”
I guess you haven’t heard of Judith Curry, Steve Koonin, Richard Lindzen, John Christie, Roy Spenser, Peter Ridd, Richard Muller, Hans von Storch, Petr Chylek, Wegman and dozens of others. I think the resignation letter below of Lennart Bengtsson – a climate scientist who briefly joined the scientific advisory committee of the skeptical Global Warming Policy Foundation – is instructive about why so few speak out. Most researchers are worried about getting peer-reviewed grants and jobs for their students. Now you have no excuse for ignorance.
“I have been put under such an enormous group pressure in recent days from all over the world that has become virtually unbearable to me. If this is going to continue I will be unable to conduct my normal work and will even start to worry about my health and safety. I see therefore no other way out therefore than resigning from GWPF. I had not expecting such an enormous world-wide pressure put at me from a community that I have been close to all my active life. Colleagues are withdrawing their support, other colleagues are withdrawing from joint authorship etc. I see no limit and end to what will happen. It is a situation that reminds me about the time of McCarthy. I would never have expecting anything similar in such an original peaceful community as meteorology. Apparently it has been transformed in recent years.”
In 2010, statisticians McShane and Wyner published a paper criticizing Mann’s latest reconstruction in a leading statistics journal entitled: “A Statistical Analysis of Multiple Temperature Proxies: Are Reconstructions of Surface Temperatures over the Last 1000 Years Reliable?” and the editor of the journal made this a discussion paper and invited and published comments from more than a dozen paleoclimatologist and statisticians. Anyone who thinks temperature reconstructions from proxy data are not controversial is either poorly informed or willfully blind.
FWIW, I personally find a lot of the conspiracy theories and pseudo-science at skeptical websites appalling. When I first came here, I wasn’t stupid enough to believe that an amateur blogger could uncover serious mistakes in the work of professional scientists. Nevertheless I found, Steve’s blog posts to be compelling and exceptionally well-documented, including the computer code and data used to construct his figures and long quotes from primary sources. These blog posts are probably some of the most thoroughly peer-reviewed climate science in existence – reviewed by dozens of enemies eager to catch any mistake, and by some highly competent readers who independently reproduced his findings and questioned his conclusions.
I would try to make two points about the above discussion.
1.
We observe a tendency to confuse science as a method and science as a social structure. For example, The peer-reviewed publishing system is part of science as a social structure. If this system generally makes it possible to gain in efficiency in the construction of knowledge, it is not part of science as a method. Such a facilitating system can fail, it can be challenged, and it can never be invoked as an argument against science as a method.
2.
Bas, in his first interventions made this statement several times:
“The point is that these series vary by 0.5 ° C or so at timescales of centuries, whereas it has increased by 0.8 ° C in the most recent 40 years.”
I think this is an important point. The increase in the global surface temperature of 0.8 ° C is indeed the value reported by the most famous specialized organizations. This value is not completely undisputed for various reasons and in particular because the warming of the lower troposphere is rather lower than that and that it should be, according to physics, on the contrary a little higher.
As for the 0.5 ° C of the proxies, it is more difficult to confirm because the proxies, even the good ones which have a simple and essential relation with the temperature, are not graduated in Kelvin nor in ° C or ° F. Having said that, my opinion is indeed that this value is quite reasonable.
If I accept these values as correct, I might be forced to accept hockey sticks. Unfortunately, I find myself in front of a rather curious enigma. All the proxies which can be shown to respond essentially and simply to temperature (this is the case in particular with melting anomalies of glaciers, tide gauges, temperature of the lower troposphere, snow cover and tree ring density) do not show any particular behavior in the last 40 years. The modern warming deduced from these proxies would not exceed 0.5 ° C and therefore perfectly in line with what they give for the older variations.
From there follows a logical conclusion: proxies and instrumental indices do not measure quite the same thing.
What exactly do each of them measure?
Hi Phi,
I agree with your statements (although I’m not sure if 0.5 C for past T variation is reasonable – more like ~1.3 C or so)
Also, Ulf Buntgen and Jan Esper et al have a new paper out in Dendrochronologia in which they offer a *possible* explanation for the divergence issue you are referring to (Arctic dimming due to aerosols).
(note this also tells us is that the science is far from settled, contrary to what others may want you to believe)
https://www.sciencedirect.com/science/article/abs/pii/S1125786521000333?via%3Dihub
https://images.squarespace-cdn.com/content/v1/5f6b3431c9737d4a00447727/1625095195171-42U0UEHZ21QPLZZB79SA/figure.jpg?format=1000w
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On another note – In my personal opinion, what I would like to see at some stage before for myself I could draw any firm conclusions, is a global (proxy-based) temperature reconstruction over the entire Holocene, preferably capturing the end of the last ice age (with good enough resolution and amplitude) that can be defended well. Then, let the climate models make a temperature hindcast over this period and use all the latest, currently assumed knowledge we have on the forcing estimates (CO2, solar, volcanic, but also orbital(!) etc). This hindcast then needs to be able to perfectly explain and match the proxy-based temperature reconstruction. If not, the climate models are wrong (if we accept the recon as the holy grail) or the recon (if we accept the models as the holy grail).
Currently to my knowledge no such study(s) exists. I know Liu et al (2014) (https://www.pnas.org/content/111/34/E3501) that had a lot of issue correctly hindcasting Holocene temperature (dubbed the Holocene temperature conundrum). (It seems Liu showed the models are very sensitive to [CO2], and not enough sensitive to orbital variations – suggesting also that a runaway greenhouse effect is unlikely if orbital forcings are much larger than CO2)
Thanks for the links.
I don’t know why, the divergence is always mentioned in relation to the high northern latitudes. If you look at the two graphs that I inserted earlier in this thread, the divergence appears global (Briffa 1998 represents the Schweingruber database for the entire northern hemisphere) and is rather attenuated at high latitude, at least for Yamal (Briffa 2013).
Otherwise, 0.5 ° C or more, the main thing is the fact that proven proxies do not exhibit very particular behavior at the end of the 20th century. No hockey stick. These hockey sticks are either statistical artifacts or chimeras.
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