Michael Mann "Hockey Stick" Definitively Established To Be Fraud - Page 2 - Politics Forum.org | PoFo

Wandering the information superhighway, he came upon the last refuge of civilization, PoFo, the only forum on the internet ...

Pollution, global warming, urbanisation etc.
Forum rules: No one line posts please.
#15031053
blackjack21 wrote:RE: MICHAEL MANN "HOCKEY STICK" DEFINITIVELY ESTABLISHED TO BE FRAUD

In 2011, the Frontier Centre for Public Policy* think tank interviewed Timothy Ball and published his allegations about Mann. Mann promptly sued for defamation. In June 2019, the Frontier Centre apologised for publishing, on its website and in letters, "untrue and disparaging accusations which impugned the character of Dr. Mann". It said that Mann had "graciously accepted our apology and retraction".


:)


* The Frontier Centre for Public Policy (FCPP) is a Canadian public policy think tank with offices in Alberta, Saskatchewan, and Manitoba. It promotes climate change denial.
#15031054
Pants-of-dog wrote:
As far as I can tell, none of that shows Mann deliberately falsified anything.


There is no question that the diagrams and accompanying text in the IPCC TAR, AR4 and WMO 1999 are misleading. I was misled. Upon considering the material presented in these reports, it did not occur to me that recent paleo data was not consistent with the historical record. The one statement in AR4 (put in after McIntyre’s insistence as a reviewer) that mentions the divergence problem is weak tea.

It is obvious that there has been deletion of adverse data in figures shown IPCC AR3 and AR4, and the 1999 WMO document. Not only is this misleading, but it is dishonest

Nor does it even mention the lawsuit.


It mentions the fraud. :lol:

fraud noun
\ ˈfrȯd \

1a: DECEIT, TRICKERY

b: an act of deceiving or misrepresenting : TRICK

I know you like citing Curry in your fallacious arguments from authority.


How is it fallacious? How did you get it in your head that appeals to authority are fallacious? And if they are fallacious then why are you constantly appealing to the authority of the "scientific consensus"?

ingliz wrote:In 2011, the Frontier Centre for Public Policy* think tank interviewed Timothy Ball and published his allegations about Mann. Mann promptly sued for defamation. In June 2019, the Frontier Centre apologised for publishing, on its website and in letters, "untrue and disparaging accusations which impugned the character of Dr. Mann". It said that Mann had "graciously accepted our apology and retraction".


So in your mind the fact that Mann bullied this think tank into a retraction is a vindication of his constructing fake graphs to mislead policy makers?
#15031056
@Sivad

Curry is not even talking about Mann there.

She is complaining about how portions of tree ring data from a guy called Keith Briffa were not shown.

Mr. Briffa excluded this data because tree ring data is not always accurate, and us usually only used as corroboration for other lines of evidence.

In this case, he excluded data that was known to give an incorrect temperature.

If you believed that Curry was accusing Mann of fraud here, you are incorrect. And she does not use the word fraud at all, as far as I can tell.

Finally:
https://en.m.wikipedia.org/wiki/Argument_from_authority
#15031058
Pants-of-dog wrote:
Curry is not even talking about Mann there.


:knife: :knife: :knife:

It was Mann's graph and it was at Mann's insistence that the Briffa series be excluded:

Mann wrote that “everyone in the room” agreed that the Briffa series was a “potential distraction/detraction from the reasonably consensus viewpoint we’d like to show”. Briffa recognized there was “pressure to present a nice tidy story as regards ‘apparent unprecedented warming in a thousand years or more ’”, but expressed many caveats, in particular that the proxies were not responding the way that they were supposed to and that that the recent warmth was “probably matched” 1000 years ago.

Otherwise, the skeptics have an field day casting doubt on our ability to understand the factors that influence these estimates and, thus, can undermine faith in the paleoestimates. I don’t think that doubt is scientifically justified, and I’d hate to be the one to have to give it fodder! (Mann Sep 22, 0938018124.txt)

Finally:
https://en.m.wikipedia.org/wiki/Argument_from_authority


:knife: :knife: :knife:


An appeal to authority is not fallacious if the authority is an actual authority and the appeal is presented as defeasible evidence(rationally compelling but not deductively valid).

An argument from authority refers to two kinds of arguments:

1) A non-fallacious argument from authority grounds a claim in the beliefs of one or more authoritative source(s), whose opinions are likely to be true on the relevant issue. Notably, insofar as the authorities in question are, indeed, experts on the issue in question, their opinion provides strong inductive support for the conclusion: It makes the conclusion likely to be true, not necessarily true. As such, an argument from authority can only strongly suggest what is true — not prove it.

2) A logically fallacious argument from authority grounds a claim in the beliefs of a source that is not authoritative. Sources could be non-authoritative because of their disagreement with consensus on the issue, their non-expertise in the relevant issue, or a number of other issues.
Correct uses of argument from authority involve deferred justification: Insofar as your claim accords with what experts on the issue believes, then your claim is also supported by the evidence the experts are relying on, even if you may not yourself be aware of what that evidence in fact is.

The expression "appeal to authority" is sometimes reserved for fallacious uses, whereas "argument from authority" is used for non-fallacious deference to experts, but this distinction is not consistently observed in practice.

https://rationalwiki.org/wiki/Argument_from_authority



If we took appeal to authority as a fallacy your entire worldview would collapse as one giant fallacy. You're really bad at logic, you should just give it up.
#15031063
[quote="Sivad”]
It was Mann's graph
[/quote]

No. Curry is explicitly discussing a chart including various sources of data that was used in an IPCC report,

and it was at Mann's insistence that the Briffa series be excluded:

Mann wrote that “everyone in the room” agreed that the Briffa series was a “potential distraction/detraction from the reasonably consensus viewpoint we’d like to show”. Briffa recognized there was “pressure to present a nice tidy story as regards ‘apparent unprecedented warming in a thousand years or more ’”, but expressed many caveats, in particular that the proxies were not responding the way that they were supposed to and that that the recent warmth was “probably matched” 1000 years ago.

Otherwise, the skeptics have an field day casting doubt on our ability to understand the factors that influence these estimates and, thus, can undermine faith in the paleoestimates. I don’t think that doubt is scientifically justified, and I’d hate to be the one to have to give it fodder! (Mann Sep 22, 0938018124.txt)


So we agree that it is not Mann’s data.

I think we should also point out that neither Briffa nor Mann did hid it.

An appeal to authority is not fallacious if the authority is an actual authority and the appeal is presented as defeasible evidence(rationally compelling but not deductively valid).


So, Curry is not an authority. She has no expertise on Mann’s motives or psychology.

Nor is her openly biased interpretation of things rationally compelling.
#15031068
Pants-of-dog wrote:No. Curry is explicitly discussing a chart including various sources of data that was used in an IPCC report,



So we agree that it is not Mann’s data.


This is so retarded, the graph relied on Mann's data and Mann's methodology. It was Mann's graph.

The term "hockey stick graph" was popularized by the climatologist Jerry Mahlman, to describe the pattern shown by the Mann, Bradley & Hughes 1999 (MBH99) reconstruction, envisaging a graph that is relatively flat with a downward trend to 1900 as forming an ice hockey stick's "shaft" followed by a sharp, steady increase corresponding to the "blade" portion.[1][2] The reconstructions have featured in Intergovernmental Panel on Climate Change (IPCC) reports as evidence of global warming.
https://en.m.wikipedia.org/wiki/Hockey_stick_graph


I think we should also point out that neither Briffa nor Mann did hid it.


:knife: I just posted quotes of Mann pushing to exclude the data. Briffa was the one being pressured by Mann to exclude the data.

On 22 September 1999, Met Office scientist Chris Folland, an IPCC lead author, alerted key researchers that a diagram of temperature change over the past thousand years "is a clear favourite for the policy makers' summary". But there were two competing graphs – Mann's hockey stick and another, by Phil Jones, Keith Briffa and others, which sought to ascertain temperatures over the past millennium using, among other things, tree rings, ice cores and coral.

Mann's graph was clearly the more compelling image of man-made climate change. Jones and Briffa's "dilutes the message rather significantly," said Folland. "We want the truth. Mike [Mann] thinks it lies nearer his result."

But Briffa did not. Three hours later, he sent a long and passionate email. "It should not be taken as read that Mike's series is THE CORRECT ONE," he warned. "I know there is pressure to present a nice tidy story as regards 'apparent unprecedented warming in a thousand years or more in the proxy data', but in reality the situation is not quite so simple... For the record, I believe that the recent warmth was probably matched about 1,000 years ago."

The row had been going on for months. Most of the correspondence is missing. But in April 1999, Ray Bradley, a co-author with Mann on the hockey stick study, was apologising for Mann's stance. "I would like to dissociate myself from Mike Mann's view [expressed in a complaint Mann had made the previous summer to the journal Science]… I find this notion quite absurd. I have worked with the UEA group for 20+ years and have great respect for them. Of course, I don't agree with everything they write, and we often have long (but cordial) arguments about what they think versus my views, but that is life… As for thinking that is it 'better that nothing appear, than something unacceptable to us'… as though we are the gatekeepers of all that is acceptable in the world of paleoclimatology seems amazingly arrogant."

Mann and Briffa eventually settled their differences. And the hockey stick was given pride of place in the IPCC report, alongside the claim that "it is likely that the 1990s have been the warmest decade and 1998 the warmest year of the millennium". Most researchers, including Briffa, now believe that statement was correct. But the emails reveal how deeply controversial it was at the time.
https://www.theguardian.com/environment ... ate-change


So, Curry is not an authority. She has no expertise on Mann’s motives or psychology.


:knife: Curry is an authority on science communication, she's definitely qualified to speak on what's misleading and what's dishonest in the presentation of science. She's been studying it and discussing it for years.

Nor is her openly biased interpretation of things rationally compelling.


Biased according to who? You? :lol:
#15031069
This iconic graph adapted from MBH99 was featured prominently in the WG1 Summary for Policymakers under a graph of the instrumental temperature record for the past 140 years. The text stated that it was "likely that, in the Northern Hemisphere, the 1990s was the warmest decade and 1998 the warmest year" in the past 1,000 years.[68] Versions of these graphs also featured less prominently in the short Synthesis Report Summary for Policymakers, which included a sentence stating that "The increase in surface temperature over the 20th century for the Northern Hemisphere is likely to have been greater than that for any other century in the last thousand years", and the Synthesis Report - Questions.

Phil Jones of the UEA Climatic Research Unit told the New York Times he was doubtful about adding the 150-year thermometer record to extend the proxy reconstruction, and compared this with putting together apples and oranges

https://en.m.wikipedia.org/wiki/Hockey_stick_graph
#15031077
Sivad wrote:This is so retarded, the graph relied on Mann's data and Mann's methodology. It was Mann's graph.

The term "hockey stick graph" was popularized by the climatologist Jerry Mahlman, to describe the pattern shown by the Mann, Bradley & Hughes 1999 (MBH99) reconstruction, envisaging a graph that is relatively flat with a downward trend to 1900 as forming an ice hockey stick's "shaft" followed by a sharp, steady increase corresponding to the "blade" portion.[1][2] The reconstructions have featured in Intergovernmental Panel on Climate Change (IPCC) reports as evidence of global warming.
https://en.m.wikipedia.org/wiki/Hockey_stick_graph


I know what the hockey stick graph is.

I also know that Curry us referring to reports that came out much later.

I just posted quotes of Mann pushing to exclude the data. Briffa was the one being pressured by Mann to exclude the data.


They excluded the data.

They did not hide it.

The data was and is publicly available.

There is a clear discussion in the reports as to why it was excluded: i.e. they pointed out how the data can lead to incorrect fundings, possible reasons for this, and methods of ensuring that this can be accounted for.

Curry is an authority on science communication, she's definitely qualified to speak on what's misleading and what's dishonest in the presentation of science. She's been studying it and discussing it for years.


No, she is an authority on certain aspects of climatology. She is not an expert on whether or not Mann is dishonest.
#15031092
Pants-of-dog wrote:I know what the hockey stick graph is.

I also know that Curry us referring to reports that came out much later.


:knife:

getting my dog to take his medicine was always a pain in the ass. I'd put the pill in his mouth, clamp his snout shut, massage his throat to get him to swallow it, but somehow he would always manage to spit the pill right back out. He'd only swallow after he figured out that it wasn't going to be over until he swallowed the pill. This reminds me of that.

Curry was referring to the 99 WMO and the IPCC reports(3 and 4):

Bad science and/or dishonesty?

There is no question that the diagrams and accompanying text in the IPCC TAR, AR4 and WMO 1999 are misleading. I was misled.

It is obvious that there has been deletion of adverse data in figures shown IPCC AR3 and AR4, and the 1999 WMO document. Not only is this misleading, but it is dishonest


They excluded the data.

They did not hide it.


They manufactured and published a highly misleading graph to deceive policy makers.

The data was and is publicly available.


No it is not. That's why the judge dismissed the suit, Mann refused to disclose his data. And it's been two decades, there is no good reason for Mann to still be sitting on that data.

According to John Hinderaker, an attorney and PowerLine blog contributor, the case was thrown out “with prejudice.”

What happened was that Dr. Ball asserted a truth defense. He argued that the hockey stick was a deliberate fraud, something that could be proved if one had access to the data and calculations, in particular the R2 regression analysis, underlying it,” Hinderaker wrote. “Mann refused to produce these documents. He was ordered to produce them by the court and given a deadline. He still refused to produce them, so the court dismissed his case.”
http://www.thegwpf.com/media-ignores-mi ... st-agenda/

Pants-of-dog wrote:There is a clear discussion in the reports as to why it was excluded:


Mann specifically pointed to a 2006 U.S. National Academy of Sciences (NAS) report that “affirmed our findings in an exhaustive independent review published in June 2006.”

Even McIntyre said subsequent studies have “produced somewhat hockey-stick-ish temperature reconstructions,” but added, “none (NONE) of our specific criticisms of Mann’s methods, proxies, and false claims has been rebutted.”

“The NAS report did not vindicate him, it said his methods were biased, and his results depended on faulty bristlecone pine records that shouldn’t be used by researchers,” McKitrick told The Daily Caller News Foundation by email.

“The NAS panel also cautioned against conclusions about warming more than 600 years back and said uncertainties were being underestimated,” McKitrick said. “That criticism applies to many subsequent studies as well.”

Indeed, the 2006 NAS reviewers agreed with the “substance” of Mann’s study but noted “claims for the earlier period covered by the study, from AD 900 to 1600, are less certain,” Nature.com reported at the time.

The NAS noted the uncertainties were “not communicated as clearly as they could have been” and “confirmed some problems with the statistics,” but those problems only had a minor impact on the overall finding, Nature.com reported.

However, NAS reviewers were extremely critical of the U.N. Intergovernmental Panel on Climate Change featuring the report so prominently in its 2001 assessment.

“The IPCC used it as a visual prominently in the report,” Kurt Cuffey, a NAS reviewer told Nature.com. “I think that sent a very misleading message about how resolved this part of the scientific research was.”


https://wattsupwiththat.com/2018/04/30/ ... n-dispute/

______________________________________


Here's how that IPCC sausage was made:

IPCC TAR and the hockey stick
Posted on April 29, 2014
by Judith Curry

Regarding the Hockey Stick of IPCC 2001 evidence now indicates, in my view, that an IPCC Lead Author working with a small cohort of scientists, misrepresented the temperature record of the past 1000 years by (a) promoting his own result as the best estimate, (b) neglecting studies that contradicted his, and (c) amputating another’s result so as to eliminate conflicting data and limit any serious attempt to expose the real uncertainties of these data. – John Christy


Back in April 2011, I had a post on The U.S. House of Representatives Hearing on Climate Change: Examining the Processes Used to Create Science and Policy. John Christy’s testimony is worth revisiting, in two contexts:

problems with the IPCC process, most recently highlighted in context of WG3 [link]
the Steyn versus Mann and Mann versus Steyn lawsuits [link]
John Christy has a unique perspective on how the hockey stick became the icon of the TAR – he served as a Lead Author (along with Michael Mann) on Chapter 2 Observed Climate Variability and Change. Relevant excerpts from Christy’s testimony:

In simplified terms, IPCC Lead Authors are nominated by their countries, and downselected by the IPCC bureaucracy with help from others (the process is still not transparent to me – who really performs this down-select?) The basic assumption is that the scientists so chosen as Lead Authors (L.A.s) represent the highest level of expertise in particular fields of climate science (or some derivative aspect such as agricultural impacts) and so may be relied on to produce the most up-to-date and accurate assessment of the science. In one sense, the authors of these reports are volunteers since they are not paid. However, they do not go without salaries. Government scientists make up a large portion of the author teams and can be assigned to do such work, and in effect are paid to work on the IPCC by their governments. University scientists aren’t so lucky but can consider their IPCC effort as being so close to their normal research activities that salary charges to the university or grants occur. Travel expenses were paid by the IPCC for trips, in my case, to Australia, Paris, Tanzania, New Zealand, Hawaii, and Victoria, Canada. Perhaps it goes without saying that such treatment might give one the impression he or she is an important authority on climate.

As these small groups of L.A.s travel the world, they tend to form close communities which often re-enforce a view of the climate system that can be very difficult to penetrate with alternative ideas (sometimes called “confirmation bias” or “myside bias”.) They become an “establishment” as I call them. With such prominent positions as IPCC L.A.s on this high profile topic, especially if they support the view that climate change is an unfolding serious disaster, they would be honored with wide exposure in the media (and other sympathetic venues) as well as rewarded with repeated appointments to the IPCC process. In my case, evidently, one stint as an L.A. was enough.

The second basic problem (the first was the murkiness of our science) with these assessments is the significant authority granted the L.A.s. This is key to understanding the IPCC process. In essence, the L.A.s have virtually total control over the material and, as demonstrated below, behave in ways that can prevent full disclosure of the information that contradicts their own pet findings and which has serious implications for policy in the sections they author. While the L.A.s must solicit input for several contributors and respond to reviewer comments, they truly have the final say.

In preparing the IPCC text, L.A.s sit in judgment of material of which they themselves are likely to be a major player. Thus they are in the position to write the text that judges their own work as well as the work of their critics. In typical situations, this would be called a conflict of interest. Thus L.A.s, being human, are tempted to cite their own work heavily and neglect or belittle contradictory evidence (see examples below.) In the beginning, the scientists who wrote the IPCC assessment were generally aware of the new responsibility, the considerable uncertainties of climate science, and that consequences of their conclusions could generate burdensome policies. The first couple of reports were relatively cautious and rather equivocal.

In my opinion, as further assessments were created, a climate “establishment” came into being, dominating not only the IPCC but many other aspects of climate science, including peer-review of journals. Many L.A.s became essentially permanent fixtures in the IPCC process and rose to positions of prominence in their institutions as a side benefit. As a result, in my view, they had a vested interest in preserving past IPCC claims and affirming evermore confident new claims to demonstrate that the science was progressing under their watch and that financial support was well spent. Speaking out as I do about this process assured my absence of significant contribution on recent and future reports. Political influence cannot be ignored. As time went on, nations would tend to nominate only those authors whose climate change opinions were in line with a national political agenda which sought perceived advantages (i.e. political capital, economic gain, etc.) by promoting the notion of catastrophic human-induced climate change. Scientists with well-known alternative views would not be nominated or selected. Indeed, it became more and more difficult for dissention and skepticism to penetrate the process now run by this establishment. As noted in my IAC testimony, I saw a process in which L.A.s were transformed from serving as Brokers of science (and policy-relevant information) to Gatekeepers of a preferred point of view.

A focus evolved in the IPCC that tended to see enhanced greenhouse gas concentrations as the cause for whatever climate changes were being observed, particularly in the 2001(Third Assessment Report or TAR) which was further solidified in 2007, (the Fourth Assessment Report or AR4.) The IAC 2010 report on the IPCC noted this overconfidence when it stated that portions of the AR4 contained “many vague statements of ‘high confidence’ that are not supported sufficiently in the literature, not put into perspective, or are difficult to refute.’” (This last claim relates to the problem of generating “unfalsifiable hypotheses” discussed in my recent House testimony.)

My experience as Lead Author in the IPCC TAR, Chapter 2 “Observed Climate Variability and Change”, allowed me to observe how a key section of this chapter, which produced the famous Hockey Stick icon, was developed. My own topic was upper air temperature changes that eventually drew little attention, even though the data clearly indicated potentially serious inconsistencies for those who would advocate considerable confidence in climate model projections.

First, note these key points about the IPCC process: the L.A. is allowed (a) to have essentially complete control over the text, (b) sit in judgment of his/her own work as well as that of his/her critics and (c) to have the option of arbitrarily dismissing reviewer comments since he/she is granted the position of “authority” (unlike peer-review.) Add to this situation the rather unusual fact that the L.A. of this particular section had been awarded a PhD only a few months before his selection by the IPCC. Such a process can lead to a biased assessment of any science. But, problems are made more likely in climate science, because, as noted, ours is a murky field of research – we still can’t explain much of what happens in weather and climate.

The Hockey Stick curve depicts a slightly meandering Northern Hemisphere cooling trend from 1000 A.D. through 1900, which then suddenly swings upward in the last 80 years to temperatures warmer than any of the millennium when smoothed. To many, this appeared to be a “smoking gun” of temperature change proving that the 20th century warming was unprecedented and therefore likely to be the result of human emissions of greenhouse gases.

I will not debate the quality of the Hockey Stick – that has been effectively done elsewhere (and indeed there is voluminous discussion on this issue), so, whatever one might think of the Hockey Stick, one can readily understand that its promotion by the IPCC was problematic given the process outlined above. Indeed, with the evidence contained in the Climategate emails, we have a fairly clear picture of how this part of the IPCC TAR went awry. For a more detailed account of this incident with documentation, see http://climateaudit.org/2009/12/10/ipcc-and-the-trick/.

We were appointed L.A.s in 1998. The Hockey Stick was prominently featured during IPCC meetings from 1999 onward. I can assure the committee that those not familiar with issues regarding reconstructions of this type (and even many who should have been) were truly enamored by its depiction of temperature and sincerely wanted to believe it was truth. Skepticism was virtually non-existent. Indeed it was described as a “clear favourite” for the overall Policy Makers Summary (Folland, 0938031546.txt). In our Sept. 1999 meeting (Arusha, Tanzania) we were shown a plot containing more temperature curves than just the Hockey Stick including one from K. Briffa that diverged significantly from the others, showing a sharp cooling trend after 1960. It raised the obvious problem that if tree rings were not detecting the modern warming trend, they might also have missed comparable warming episodes in the past. In other words, absence of the Medieval warming in the Hockey Stick graph might simply mean tree ring proxies are unreliable, not that the climate really was relatively cooler.

The Briffa curve created disappointment for those who wanted “a nice tidy story” (Briffa 0938031546.txt). The L.A. remarked in emails that he did not want to cast “doubt on our ability to understand factors that influence these estimates” and thus, “undermine faith in paleoestimates” which would provide “fodder” to “skeptics” (Mann 0938018124.txt). One may interpret this to imply that being open and honest about uncertainties was not the purpose of this IPCC section. Between this email (22 Sep 1999) and the next draft sent out (Nov 1999, Fig. 2.25 Expert Review) two things happened: (a) the email referring to a “trick” to “hide the decline” for the preparation of report by the World Meteorological Organization was sent (Jones 0942777075.txt, “trick” is apparently referring to a splicing technique used by the L.A. in which non-paleo data were merged

to massage away a cooling dip at the last decades of the original Hockey Stick) and (b) the cooling portion of Briffa’s curve had been truncated for the IPCC report (it is unclear as to who performed the truncation.)

In retrospect, this disagreement in temperature curves was simply an indication that such reconstructions using tree ring records contain significant uncertainties and may be unreliable in ways we do not currently understand or acknowledge. This should have been explained to the readers of the IPCC TAR and specifically our chapter. Highlighting that uncertainty would have been the proper scientific response to the evidence before us, but the emails show that some L.A.’s worried it would have diminished a sense of urgency about climate change (i.e. “dilutes the message rather significantly”, Folland, 0938031546.txt.)

When we met in February 2000 in Auckland NZ, the one disagreeable curve, as noted, was not the same anymore because it had been modified and truncated around 1960. Not being aware of the goings-on behind the scenes, I had apparently assumed a new published time series had appeared and the offensive one had been superceded (I can’t be certain of my actual thoughts in Feb. 2000). Now we know, however, that the offensive part of Briffa’s curve had simply been amputated after a new realization was created three months before. (It appears also that this same curve was apparently a double amputee, having its first 145 years chopped off too, see http://climateaudit.org/2011/03/23/13321/.) So, at this point, data which contradicted the Hockey Stick, whose creator was the L.A., had been eliminated. No one seemed to be alarmed (or in my case aware) that this had been done.

Procedures to guard against such manipulation of evidence are supposed to be in place whenever biases and conflicts of interest interfere with duties to report the whole truth, especially in assessments that have such potentially drastic policy implications. That the IPCC allowed this episode to happen shows, in my view, that the procedures were structurally deficient.

Even though the new temperature chart appeared to agree with the Hockey Stick, I still expressed my skepticism in this reconstruction as being evidence of actual temperature variations. Basically, this result relied considerably on a type of western U.S. tree-ring not known for its fidelity in reproducing large-scale temperatures (NRC 2006, pg. 52).

At the L.A. meetings, I indicated that there was virtually no inter-century precision in these measurements, i.e. they were not good enough to tell us which century might be warmer than another in the pre-calibration period (1000 to 1850.)

In one Climategate email, a Convening L.A., who wanted to feature the Hockey Stick at the time (though later was less enthusiastic), mentions “The tree ring results may still suffer from lack of multicentury time scale variance” and was “probably the most important issue to resolve in Chapter 2” (Folland, 0938031546.txt). This, in all likelihood, was a reference to (a) my expressed concern (see my 2001 comments to NRC below) as well as to (b) the prominence to which the Hockey Stick was pre destined.

To compound this sad and deceptive situation, I had been quite impressed with some recent results by Dahl-Jensen et al., (Science 1998), in which Greenland ice-borehole temperatures had been deconvolved into a time series covering the past 20,000 years. This measurement indeed presented inter-century variations. Their result indicated a clear 500-year period of temperatures, warmer than the present, centered about 900 A.D. – commonly referred to as the Medieval Warm Period, a feature noticeably absent in the Hockey Stick. What is important about this is that whenever any mid to high-latitude location shows centuries of a particularly large temperature anomaly, the spatial scale that such a departure represents is also large. In other words, long time periods of warmth or coolness are equivalent to large spatial domains of warmth or coolness, such as Greenland can represent for the Northern Hemisphere (the domain of the Hockey Stick.)

I discussed this with the paleo-L.A. at each meeting, asking that he include this exceptional result in the document as evidence for temperature fluctuations different from his own. To me Dahl-Jensen et al.’s reconstruction was a more robust estimate of past temperatures than one produced from a certain set of western U.S. tree-ring proxies. But as the process stood, the L.A. was not required to acknowledge my suggestions, and I was not able to convince him otherwise. It is perhaps a failure of mine that I did not press the issue even harder or sought agreement from others who might have been likewise aware of the evidence against the Hockey Stick realization.

As it turned out, this exceptional paper by Dahl-Jensen et al. was not even mentioned in the appropriate section (TAR 2.3.2). There was a brief mention of similar evidence indicating warmer temperatures 1000 years ago from the Sargasso Sea sediments (TAR 2.3.3), but the text then quickly asserts, without citation, that this type of anomaly is not important to the hemisphere as a whole.

Thus, we see a situation where a contradictory data set from Greenland, which in terms of paleoclimate in my view was quite important, was not offered to the readers (the policymakers) for their consideration. In the end, the Hockey Stick appeared in Figure 1 of the IPCC Summary for Policymakers, without any other comparisons, a position of prominence that speaks for itself.

So, to summarize, an L.A. was given final say over a section which included as its (and the IPCC’s) featured product, his very own chart, and which allowed him to leave out not only entire studies that presented contrary evidence, but even to use another strategically edited data set that had originally displayed contrary evidence. This led to problems that have only recently been exposed. This process, in my opinion, illustrates that the IPCC did not provide policymakers with an unbiased evaluation of the science, whatever one thinks about the Hockey Stick as a temperature reconstruction.

JC comments: Christy’s assessment, when combined with the UEA emails, provides substantial insight into how this hockey stick travesty occurred. My main unanswered question is: How did Michael Mann become a Lead Author on the TAR? He received his Ph.D. in 1998, and presumably he was nominated or selected before the ink was dry on his Ph.D. It is my suspicion that the U.S. did not nominate Mann (why would they nominate someone for this chapter without a Ph.D.?) Here is the only thing I can find on the U.S. nomination process [link]. Instead, I suspect that the IPCC Bureau selected Mann; it seems that someone (John Houghton?) was enamored of the hockey stick and wanted to see it featured prominently in the TAR. The actual selection of Lead Authors by the IPCC Bureau is indeed a mysterious process.

The IPCC process is clearly broken, and I don’t see anything in their recent policies that addresses the problems that Christy raises. The policy makers clearly wrought havoc in context of the AR5 WG3 report; however there is a more insidious problem particularly with the WG1 scientists in terms of conflict of interest and the IPCC Bureau in terms of stacking the deck to produce the results that they want.


Dr. John Christy Testimony - Full House Committee Hearing






Scientists Behaving Badly

In a 1996 email to a large number of scientists in the CRU circle, Tom Wigley, a top climatologist working at the National Center for Atmospheric Research in Colorado, cautioned: "I support the continued collection of such data, but I am disturbed by how some people in the paleo community try to oversell their product." Mann and his colleagues made use of some of the CRU data, but some of the CRU scientists weren't comfortable with the way Mann represented it and also seemed to find Mann more than a bit insufferable.

CRU scientist Keith Briffa, whose work on tree rings in Siberia has been subject to its own controversies, emailed Edward Cook of Columbia University: "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," adding that he was tired of "the increasing trend of self-opinionated verbiage [Mann] has produced over the last few years .  .  . and (better say no more)."

Cook replied: "I agree with you. We both know the probable flaws in Mike's recon[struction], particularly as it relates to the tropical stuff. Your response is also why I chose not to read the published version of his letter. It would be too aggravating. .  .  . It is puzzling to me that a guy as bright as Mike would be so unwilling to evaluate his own work a bit more objectively."

In yet another revealing email, Cook told Briffa: "Of course [Bradley] and other members of the MBH [Mann, Bradley, Hughes] camp have a fundamental dislike for the very concept of the MWP, so I tend to view their evaluations as starting out from a somewhat biased perspective, i.e. the cup is not only 'half-empty'; it is demonstrably 'broken'. I come more from the 'cup half-full' camp when it comes to the MWP, maybe yes, maybe no, but it is too early to say what it is."

In another email to Briffa, Cook complains about Bradley, too: "His air of papal infallibility is really quite nauseating at times."

Even as the IPCC was picking up Mann's hockey stick with enthusiasm, Briffa sent Mann a note of caution about "the possibility of expressing an impression of more consensus than might actually exist. I suppose the earlier talk implying that we should not 'muddy the waters' by including contradictory evidence worried me. IPCC is supposed to represent consensus but also areas of uncertainty in the evidence." Briffa had previously dissented from the hockey stick reconstruction in a 1999 email to Mann and Phil Jones: "I believe that the recent warmth was probably matched about 1000 years ago." Even Malcolm Hughes, one of the original hockey stick coauthors, privately expressed reservations about overreliance on their invention, writing to Cook, Mann and others in 2002:

All of our attempts, so far, to estimate hemisphere-scale temperatures for the period around 1000 years ago are based on far fewer data than any of us would like. None of the datasets used so far has anything like the geographical distribution that experience with recent centuries indicates we need, and no one has yet found a convincing way of validating the lower-frequency components of them against independent data. As Ed [Cook] wrote, in the tree-ring records that form the backbone of most of the published estimates, the problem of poor replication near the beginnings of records is particularly acute, and ubiquitous. .  .  . Therefore, I accept that everything we are doing is preliminary, and should be treated with considerable caution.


Mann didn't react well to these hesitations from his colleagues. Even Ray Bradley, a coauthor of the hockey stick article, felt compelled to send a message to Briffa after one of Mann's self-serving emails with the single line: "Excuse me while I puke." One extended thread grew increasingly acrimonious as Mann lashed out at his colleagues. He wrote to Briffa, Jones, and seven others in a fury over their favorable remarks about a Science magazine article that offered a temperature history that differed from the hockey stick: "Sadly, your piece on the Esper et al paper is more flawed than even the paper itself. .  .  . There is a lot of damage control that needs to be done and, in my opinion, you've done a disservice to the honest discussions we had all had in the past, because you've misrepresented the evidence."

To Briffa in particular Mann wrote: "Hopefully, you know that I respect you quite a bit as a scientist! But in this case, I think you were sloppy. And the sloppiness had a real cost." Mann's bad manners prompted Bradley to reply: "I wish to disassociate myself with Mike's comments, or at least the tone of them. I do not consider myself the final arbiter of what Science should publish, nor do I consider what you did to signify the end of civilization as we know it." Tempers got so out of hand that Tom Crowley of Duke University intervened: "I am concerned about the stressed tone of some of the words being circulated lately. .  .  . I think you are all fine fellows and very good scientists and that it is time to smoke the peace pipe on all this and put a temporary moratorium on more email messages until tempers cool down a bit." Mann responded with his best imitation of Don Corleone: "This is ultimately about the science, it's not personal." If the CRU circle treat each other this way, it is no wonder they treat skeptics even more rudely.

One of Briffa's concerns about Mann's hockey stick is that some of the tree ring data--Briffa's specialty--didn't match up well with other records, so Mann either omitted them (in some versions of the hockey stick) or changed their statistical weighting in his overall synthesis to downplay the anomalous results of the raw data. This, by the way, is the origin of Phil Jones's "hide the decline" email; after 1960 tree ring data suggest a decline in temperatures, while other datasets show an increase. (This is one of many sources of intense controversy about temperature reconstructions.) Jones's and Mann's treatment may be defensible, but is problematic to say the least.


[...]the National Academy of Sciences appointed an expert review panel to look into the dispute. The NAS reported its findings in 2006, and the language was sufficiently hedged in diplomatic equivocations that Mann and the media claimed the hockey stick had been vindicated. But a close reading shows that the NAS report devastated the hockey stick. While the NAS said the hockey stick reconstruction was a "plausible" depiction of 20th-century warming, the report went on to state clearly that

substantial uncertainties currently present in the quantitative assessment of large-scale surface temperature changes prior to about A.D. 1600 lower our confidence in this conclusion compared to the high level of confidence we place in the Little Ice Age cooling and 20th century warming. Even less confidence can be placed in the original conclusions by Mann et al. (1999) that "the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millennium."


One of the NAS committee members, physicist Kurt Cuffey of the University of California, was more direct in remarks to Science magazine: "The IPCC used [the hockey stick] as a visual prominently in the [2001] report. I think that sent a very misleading message about how resolved this part of the scientific research was." Mann's hockey stick, a centerpiece of the 2001 IPCC report, did not appear in the 2007 IPCC report.

The NAS report, it should be added, included an implicit rebuke of Mann and his colleagues for their reluctance to share their data with other researchers:

The committee recognizes that access to research data is a complicated, discipline-dependent issue, and that access to computer models and methods is especially challenging because intellectual property rights must be considered. Our view is that all research benefits from full and open access to published datasets and that a clear explanation of analytical methods is mandatory. Peers should have access to the information needed to reproduce published results, so that increased confidence in the outcome of the study can be generated inside and outside the scientific community.


Despite this criticism and rebuke from the NAS, the Climate Research Unit hockey team continued refusing right up to this month to share its raw data and computer codes with McIntyre and McKitrick or anyone else. Mann continued to insist that the medieval warm period was overestimated, and he keeps on producing more new hockey sticks than the NHL (he has another one out this week in Science magazine). Some of the egregious emails in the stash include suggestions that everyone delete emails related to their work on the IPCC process to shield them from FOIA requests (possibly illegal) and, according to one of Jones's emails, actually destroying the raw data in the face of a successful FOIA requisition. Jones writes to Mann in one 2005 message: "Don't leave stuff lying around on ftp sites--you never know who is trawling them. The two MMs [McIntyre and McKitrick] have been after the CRU station data for years. If they ever hear there is a Freedom of Information Act now in the UK, I think I'll delete the file rather than send to anyone." Jones now claims no emails were deleted, but he'll need to explain his December 3, 2008, message to Ben Santer--a climate researcher at Lawrence Livermore National Laboratory--about a new FOIA request from McIntyre: "I am supposed to go through my emails and he can get anything I've written about him. About 2 months ago I deleted loads of emails, so have very little--if anything at all."

https://www.washingtonexaminer.com/week ... ving-badly
#15031102
Sivad wrote:drug patents aren't secret, pharmaceutical companies have to disclose everything about a drug right down to its molecular structure.


Maybe it’s a copyright issue, I don’t know :?: I was just trying to give him the benefit of the doubt. Truth be told, I don’t actually care lol and on that note, I will leave you with PoD who will ask you to be demonstrably demonstrative for the next 10 pages no matter what you do. Good luck. ;)
#15031103
Sivad wrote:Curry was referring to the 99 WMO and the IPCC reports(3 and 4):


....and the only data to which her criticisms pertain is Briffa’s.

This is not the data that is discussed in the lawsuit.

They manufactured and published a highly misleading graph to deceive policy makers.


Your unverifiable speculation about motives is emotional character assassination.

Since they clearly discussed what data they excluded, why they excluded it, and the implications, it is misleading to describe them as being deceptive.

No it is not. That's why the judge dismissed the suit, Mann refused to disclose his data. And it's been two decades, there is no good reason for Mann to still be sitting on that data.

According to John Hinderaker, an attorney and PowerLine blog contributor, the case was thrown out “with prejudice.”

What happened was that Dr. Ball asserted a truth defense. He argued that the hockey stick was a deliberate fraud, something that could be proved if one had access to the data and calculations, in particular the R2 regression analysis, underlying it,” Hinderaker wrote. “Mann refused to produce these documents. He was ordered to produce them by the court and given a deadline. He still refused to produce them, so the court dismissed his case.”
http://www.thegwpf.com/media-ignores-mi ... st-agenda/


Yes, that is what happened.

And then you argued that the only reason he refused to comply with this request is because he is a big meanie liar. You have failed to support that.

But the data Curry is discussing here is Briffa’s. This data is, as I claimed, available.

——————————

Is there an argument in all that stuff you decided to copy and paste?
#15031107
Pants-of-dog wrote:....and the only data to which her criticisms pertain is Briffa’s.


This is beyond total pofo, this is total pofo on crack. Whatever, I posted all the info anyone would ever need to understand what a crazy fucking fraud Michael E Mann is and you have graciously demonstrated what ludicrous depths of bullshit someone has to sink to in order to deny it.
Last edited by Sivad on 02 Sep 2019 01:52, edited 1 time in total.
#15031108
SSDR wrote:Someone does not have to use their "own" terms to debate against your views. There is nothing wrong with using other reliable sources.


Sure.

What exactly is the argument?

————————-

@Sivad

If all you have left is insults, then you have failed to support your argument.
#15031116
ingliz wrote:In 2011, the Frontier Centre for Public Policy* think tank interviewed Timothy Ball and published his allegations about Mann. Mann promptly sued for defamation. In June 2019, the Frontier Centre apologised for publishing, on its website and in letters, "untrue and disparaging accusations which impugned the character of Dr. Mann". It said that Mann had "graciously accepted our apology and retraction".


:)


* The Frontier Centre for Public Policy (FCPP) is a Canadian public policy think tank with offices in Alberta, Saskatchewan, and Manitoba. It promotes climate change denial.


So, the organization rolled over but the man didn’t? Is that about right?

Edit - I just did a quick Wikipedia scan on this Ball fellow. My conclusion is that the field of climatology is bitchy and litigious. I doubt that’s confined to Canada :|
#15031124
ingliz wrote:In 2011, the Frontier Centre for Public Policy* think tank interviewed Timothy Ball and published his allegations about Mann. Mann promptly sued for defamation. In June 2019, the Frontier Centre apologised for publishing, on its website and in letters, "untrue and disparaging accusations which impugned the character of Dr. Mann". It said that Mann had "graciously accepted our apology and retraction".


:)


* The Frontier Centre for Public Policy (FCPP) is a Canadian public policy think tank with offices in Alberta, Saskatchewan, and Manitoba. It promotes climate change denial.

They accepted Mann's demands in order to avoid being sued. Ball did not accept Mann's demands. Much of AGW propaganda depends upon creating the illusion of a "scientific consensus" and stifling people from debating. When the plaintiff gets a suit dismissed with prejudice for refusing to provide the evidence central to his own legal claim, it's devastating to his credibility.

Sivad wrote:There is no question that the diagrams and accompanying text in the IPCC TAR, AR4 and WMO 1999 are misleading. I was misled. Upon considering the material presented in these reports, it did not occur to me that recent paleo data was not consistent with the historical record. The one statement in AR4 (put in after McIntyre’s insistence as a reviewer) that mentions the divergence problem is weak tea.

It is obvious that there has been deletion of adverse data in figures shown IPCC AR3 and AR4, and the 1999 WMO document. Not only is this misleading, but it is dishonest

It mentions the fraud. :lol:

fraud noun
\ ˈfrȯd \

1a: DECEIT, TRICKERY

b: an act of deceiving or misrepresenting : TRICK

How is it fallacious? How did you get it in your head that appeals to authority are fallacious? And if they are fallacious then why are you constantly appealing to the authority of the "scientific consensus"?

So in your mind the fact that Mann bullied this think tank into a retraction is a vindication of his constructing fake graphs to mislead policy makers?

The interesting thing is that they go to great lengths also to hide the HadCRU hack information, while purporting to be transparent.

If Mann were correct, he could have proven his case in a court of law and received monetary damages. The fact that he refused to do so--in a case he filed no less--demonstrates that he COULD NOT provide the evidence to sustain his case.
#15031146
SSDR wrote:Someone does not have to use their "own" terms to debate against your views. There is nothing wrong with using other reliable sources.


Who in the hell wants to debate ignorant opinions, I wish PoD would spare us all his original musings and just post solid information. I want to get to the reality, I have zero interest in uniformed politically motivated opinions and poorly reasoned fact free analysis.
#15031235
Pants-of-dog wrote:Then why do you uncritically copy and paste the unformed politically motivated opinions and poorly reasoned fact free analysis


I don't. In this thread I've presented the opinions and analysis of chairs of three of the largest and most prestigious major research university climate science departments in the world, the findings of the National Academy of Science on Mann's proxy reconstructions, the assessment of a senior physicist at the Lawrence Berkeley National Laboratory, and the criticisms and objections of Mann's work and methods by his own colleagues at the Climatic Research Unit.

You responded to all of that by just making up crazy bullshit and going into obtuse denial mode.

Here's the National Academy of Science on the reliability of Mann's reconstructions:


Testimony
Title: Questions Surrounding the 'Hockey Stick' Temperature Studies: Implications for Climate Change Assessments
Date: 07/19/2006
Session: 109th Congress (Second Session)
Witness(es): Gerald R. North
Credentials:
Distinguished Professor, Department of Atmospheric Sciences, Texas A&M University, and Chairman, Committee on Surface Temperature Reconstructions for the Last 2,000 Years, Board on Atmospheric Sciences and Climate, Division on Earth and Life Studies, National Research Council/National Academy of Sciences, The National Academies

Chamber: House
Committee: Committee on Energy and Commerce
Surface Temperature Reconstructions for the Last 2,000 Years


U.S. House of Representatives

July 19, 2006

Good morning, Mr. Chairman and members of the Committee. My name is Jerry North. I am the Harold J. Haynes Endowed Chair in Geosciences and a Distinguished Professor in the Department of Atmospheric Sciences at Texas A&M University, and I served as chair of the National Research Council’s Committee on Surface Temperature Reconstructions for the Last 2,000 Years. The National Research Council is the operating arm of the National Academy of Sciences, National Academy of Engineering, and the Institute of Medicine, chartered by Congress in 1863 to advise the government on matters of science and technology.


My comments today will highlight the key findings of our committee’s recent report on Surface Temperature Reconstructions for the Last 2,000 Years, which was prepared in response to a request from Chairman Boehlert of the House Committee on Science. Our task was to assess the state of scientific efforts to reconstruct surface temperature records for the Earth over the past few hundred to few thousand years, and to comment on the implications of these efforts for our understanding of global climate change. I would like to stress, in advance, that surface temperature reconstructions are only one of multiple lines of evidence supporting the conclusion that the climate is warming in response to human activities, and they are not the primary evidence. In fact, man-made climate change is quite real. However, our report did not examine projections of future climate change in any detail, and it does not make policy recommendations.

Let me begin by briefly explaining how scientists go about reconstructing surface temperatures for the past few millennia. Because widespread thermometer measurements are only available for the last 150 years or so, scientists estimate temperatures in the more distant past by analyzing what we call proxy evidence. Common proxies include tree rings, corals, ocean and lake sediments, cave deposits, ice cores, glacier records, boreholes, and historical documents. To give one example, the annual growth rings in a tree can tell us about the climate at that location when the growth occurred -- a thicker ring indicates better growing conditions than a narrow ring. Likewise, the advances and retreats of glaciers around the world provide evidence of warming and cooling.

Starting in the 1990s, scientists began using sophisticated methods to combine proxy evidence from many different locations in an effort to estimate surface temperature changes averaged over broad geographic regions during the last few hundred to few thousand years. These large-scale surface temperature reconstructions have enabled researchers to estimate past temperature variations over the Northern Hemisphere or even the entire globe, often with time resolution as fine as decades or even individual years.


The papers that have attracted the most attention in this research area were written by Michael Mann, Raymond Bradley and Malcolm Hughes in 1998 and 1999. Dr. Mann and his colleagues used a new methodology to combine data from a number of sources to estimate temperatures in the Northern Hemisphere for the last six centuries, and then for the last 1,000 years. This research received wide attention, in part because the authors concluded that the Northern Hemisphere was warmer during the late 20th century than at any other time during the past millennium, and also because it was illustrated with a simple graphic, the so-called hockey stick curve, that was featured prominently in the 2001 Intergovernmental Panel on Climate Change report.

Our committee was composed of 12 members with expertise in a range of fields including climate modeling, statistics, climate change and variability, and each of the types of proxies commonly used for climate reconstructions. The committee took multiple steps to accomplish its charge. First, we hosted a two-day workshop in March 2006 and invited numerous speakers from all perspectives in the debate to participate. We examined the scientific literature in great depth, and considered written input from many sources. The evidence we considered included large-scale surface temperature reconstructions from a number of different research teams, as well as local and regional proxy evidence collected from a number of locations around the world. We also looked at the instrumental record and examined various statistical considerations.

Let me summarize five key conclusions we reached after reviewing the evidence:

1. The instrumentally measured warming of about 1°F during the 20th century is also reflected in borehole temperature measurements, the retreat of glaciers, and other observational evidence, and can be simulated with climate models.

2. Large-scale surface temperature reconstructions yield a generally consistent picture of temperature trends during the preceding millennium, including relatively warm conditions centered around A.D. 1000 (identified by some as the “Medieval Warm Period”) and a relatively cold period (or “Little Ice Age”) centered around 1700.

3. It can be said with a high level of confidence that global mean surface temperature was higher during the last few decades of the 20th century than during any comparable period during the preceding four centuries. This statement is justified by the consistency of the evidence from a wide variety of geographically diverse proxies.

4. Less confidence can be placed in large-scale surface temperature reconstructions for the period A.D. 900 to 1600. Presently available proxy evidence indicates that temperatures at many, but not all, individual locations were higher during the past 25 years than during any period of comparable length since A.D. 900. The uncertainties increase substantially backward in time through this period and are not yet fully quantified.

5. Very little confidence can be assigned to statements concerning the hemispheric mean or global mean surface temperature prior to about A.D. 900.


The main reason that our confidence in large-scale surface temperature reconstructions is lower before A.D. 1600 and especially before A.D. 900 is the relative scarcity of precisely dated proxy evidence. Other factors limiting our confidence in surface temperature reconstructions include the relatively short length of the instrumental record, the fact that all proxies are influenced by many climate variables, and the possibility that the relationship between proxy data and local surface temperatures may have varied over time. All of these considerations introduce uncertainties that are difficult to quantify.

Overall, the committee finds that efforts to reconstruct temperature histories for broad geographic regions using multiproxy methods are an important contribution to climate research and that these large-scale surface temperature reconstructions contain meaningful climatic signals. The individual proxy series used to create these reconstructions generally exhibit strong correlations with local environmental conditions, and in most cases there is a physical, chemical, or physiological reason why the proxy reflects local temperature variations. Our confidence in the results of these reconstructions becomes stronger when multiple independent lines of evidence point to the same general result, as in the case of the Little Ice Age cooling and the 20th century warming.


The basic conclusion of the 1999 paper by Dr. Mann and his colleagues was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes both additional large-scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators, such as melting on icecaps and the retreat of glaciers around the world, which in many cases appear to be unprecedented during at least the last 2,000 years.

Based on the analyses presented in the original papers by Mann et al. (1998, 1999) and this newer supporting evidence, the committee finds it plausible that the Northern Hemisphere was warmer during the last few decades of the 20th century than during any comparable period over the preceding millennium. However, the substantial uncertainties currently present in the quantitative assessment of large-scale surface temperature changes prior to about A.D. 1600 lower our confidence in this conclusion compared to the high level of confidence we place in the Little Ice Age cooling and 20th century warming. Even less confidence can be placed in the original conclusions by Mann et al. (1999) that “the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millennium” because the uncertainties inherent in temperature reconstructions for individual years and decades are larger than those for longer time periods, and because not all of the available proxies record temperature information on such short timescales. We also question some of the statistical choices made in the original papers by Dr. Mann and his colleagues. However, our reservations with some aspects of the original papers by Mann et al. should not be construed as evidence that our committee does not believe that the climate is warming, and will continue to warm, as a result of human activities.

Large-scale surface temperature reconstructions are only one of multiple lines of evidence supporting the conclusion that climatic warming is occurring in response to human activities, and they are not the primary evidence. The scientific consensus regarding human-induced global warming would not be substantively altered if, for example, the global mean surface temperature 1,000 years ago was found to be as warm as it is today. This is because reconstructions of surface temperature do not tell us why the climate is changing. To answer that question, one would need to examine the factors, or forcings, that influence the climate system. Prior to the Industrial Revolution, the primary climate forcings were changes in volcanic activity and in the output of the Sun, but the strength of these forcings is not very well known. In contrast, the increasing concentrations of greenhouse gases in the atmosphere over the past century are consistent with both the magnitude and the geographic pattern of warming seen by thermometers.


One significant part of the controversy on this issue is related to data access. The collection, compilation, and calibration of paleoclimatic proxy data represent a substantial investment of time and resources, often by large teams of researchers. The committee recognizes that access to research data is a complicated, discipline-dependent issue, and that access to computer models and methods is especially challenging because intellectual property rights must be considered.

Our view is that all research benefits from full and open access to published datasets and that a clear explanation of analytical methods is mandatory. Peers should have access to the information needed to reproduce published results, so that increased confidence in the outcome of the study can be generated inside and outside the scientific community. Paleoclimate research would benefit if individual researchers, professional societies, journal editors, and funding agencies continued their efforts to ensure that existing open access practices are followed.


So where do we go from here? Large-scale surface temperature reconstructions have the potential to further improve our knowledge of temperature variations over the last 2,000 years, particularly if additional proxy evidence can be identified and obtained from areas where the coverage is relatively sparse and for time periods before A.D. 1600 and especially before A.D. 900. It would also be helpful to update proxy records that were collected decades ago, in order to develop more reliable calibrations with the instrumental record.

http://www.nationalacademies.org/OCGA/1 ... CGA_150987
  • 1
  • 2
  • 3
  • 4
  • 5
  • 7

@FiveofSwords Changing your argument is calle[…]

Israel-Palestinian War 2023

Handcuffed medics, patients with medical equipment[…]

These protests are beautiful. And again..the kids […]

Indictments have occured in Arizona over the fake[…]