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Continuing Problems with Paleoclimate Proxies

Jack Hays

Jack Hays

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As I have pointed out often, the MBH98 hockey stick has been replicated because MBH98's errors were replicated. Here Steve McIntyre looks at recent updates to South American proxies, and finds the errors sadly durable.

[h=2]PAGES2K (2017) – South America Revisited[/h]Oct 7, 2018 – 4:54 PM
The most recent large-scale compilation of proxy records over the past two millennia is PAGES (2017). They made a concerted effort to archive data (to the credit of Julien Emile-Geay), archiving 692 series, but they perpetuated most other sins within the field. Rather than abjuring ex post screening, it carried ex post screening to extremes never previously contemplated: tree ring chronologies with negative correlations to temperature are now banished from view altogether. However, its self-professed quality control did not exclude stripbark bristlecone chronologies, which continue to populate the network.
In keeping with my preference to look at regions and proxy types before worrying too much about aggregates, I looked at their South American network, which is an update of the South American network of PAGES2K (2013), which I discussed a few days after publication here. There were major changes between 2013 and 2017 networks, which were not elucidated in the later study, but which will be discussed in today’s article. The changes illustrate the profound problems with the tree ring chronologies and lake sediment series which make up the vast majority of data in PAGES 2017 and similar studies. Continue reading →

. . . . Summary
The eight PAGES2017 series are summarized in a consistent panel plot below for the period 1000 on.
southamerica_2017.png

The tree ring component of this network is, more or less, a reductio ad absurdum of tree ring chronologies as useful temperature proxies: only four of 63 original tree chronologies have sufficient Hockey Stick-ness to be retained in the network, with even these poor remnants reverting to the mean in the 21st century updates. There is negligible similarity between the three lake sediment series, each of which uses a different indicator, though similar measurements appear to have been taken for all three sites. The only series with a meaningful HS (Chepical) appears to result from construction of a dam in 1885AD, rather than from increased temperature. This leaves the Quelccaya ice core series – which was a staple of temperature reconstructions as early as 1998 and, which, ironically, was used upside down in PAGES2K (2013), corrected in PAGES 2017 without disclosure/admission of the earlier error.
All in all, a rather pathetic show by PAGES2K.
​
 
Jack Hays said:
As I have pointed out often, the MBH98 hockey stick has been replicated because MBH98's errors were replicated. Here Steve McIntyre looks at recent updates to South American proxies, and finds the errors sadly durable.

[h=2]PAGES2K (2017) – South America Revisited[/h]Oct 7, 2018 – 4:54 PM
The most recent large-scale compilation of proxy records over the past two millennia is PAGES (2017). They made a concerted effort to archive data (to the credit of Julien Emile-Geay), archiving 692 series, but they perpetuated most other sins within the field. Rather than abjuring ex post screening, it carried ex post screening to extremes never previously contemplated: tree ring chronologies with negative correlations to temperature are now banished from view altogether. However, its self-professed quality control did not exclude stripbark bristlecone chronologies, which continue to populate the network.
In keeping with my preference to look at regions and proxy types before worrying too much about aggregates, I looked at their South American network, which is an update of the South American network of PAGES2K (2013), which I discussed a few days after publication here. There were major changes between 2013 and 2017 networks, which were not elucidated in the later study, but which will be discussed in today’s article. The changes illustrate the profound problems with the tree ring chronologies and lake sediment series which make up the vast majority of data in PAGES 2017 and similar studies. Continue reading →

. . . . Summary
The eight PAGES2017 series are summarized in a consistent panel plot below for the period 1000 on.
southamerica_2017.png

The tree ring component of this network is, more or less, a reductio ad absurdum of tree ring chronologies as useful temperature proxies: only four of 63 original tree chronologies have sufficient Hockey Stick-ness to be retained in the network, with even these poor remnants reverting to the mean in the 21st century updates. There is negligible similarity between the three lake sediment series, each of which uses a different indicator, though similar measurements appear to have been taken for all three sites. The only series with a meaningful HS (Chepical) appears to result from construction of a dam in 1885AD, rather than from increased temperature. This leaves the Quelccaya ice core series – which was a staple of temperature reconstructions as early as 1998 and, which, ironically, was used upside down in PAGES2K (2013), corrected in PAGES 2017 without disclosure/admission of the earlier error.
All in all, a rather pathetic show by PAGES2K.
​
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Yet you only have blogs to verify your misinformation.
 
In the comments section of the OP link is an interesting tidbit about Michael Mann's initial rejection of PAGES2K in 2013.



  • 7c39665ed80f29aa88a4313b7bc9b877
    Climate Audit
    Posted Oct 8, 2018 at 10:07 AM | Permalink | Reply​
    Mann’s primary criticism of PAGES2K was the sensible observation that it included multiple regional studies, each of which ought to be properly reviewed prior to reliance, and that it was impossible to properly review so many regional studies as part of an aggregate. It was rejected by Science after it had been used in the Second Order Draft (where it had been relied upon for a key graphic.)
    The authors (and presumably IPCC) then pressured Nature to get it accepted in time. Ultimately, Keith Briffa concocted the idea of accepting it as an opinion piece which did not require the same level of peer review as a Letter, secure in the knowledge that IPCC wouldn’t care about the standard as long as it was accepted somewhere. On this basis, Nature accepted it at 5 minutes to midnight on the last day of eligibility for IPCC (the identical timing to Wahl and Ammann acceptance in the previous IPCC report.)
 
Jack Hays said:
In the comments section of the OP link is an interesting tidbit about Michael Mann's initial rejection of PAGES2K in 2013.



  • 7c39665ed80f29aa88a4313b7bc9b877
    Climate Audit
    Posted Oct 8, 2018 at 10:07 AM | Permalink | Reply​
    Mann’s primary criticism of PAGES2K was the sensible observation that it included multiple regional studies, each of which ought to be properly reviewed prior to reliance, and that it was impossible to properly review so many regional studies as part of an aggregate. It was rejected by Science after it had been used in the Second Order Draft (where it had been relied upon for a key graphic.)
    The authors (and presumably IPCC) then pressured Nature to get it accepted in time. Ultimately, Keith Briffa concocted the idea of accepting it as an opinion piece which did not require the same level of peer review as a Letter, secure in the knowledge that IPCC wouldn’t care about the standard as long as it was accepted somewhere. On this basis, Nature accepted it at 5 minutes to midnight on the last day of eligibility for IPCC (the identical timing to Wahl and Ammann acceptance in the previous IPCC report.)
Click to expand...

LOL.

Because Nature editors stay up til midnight, biting their nails to approve publications just minutes before someone else’s deadline.


Also, Pages 2k was published as a progress article..basically an invited review. As such it is most definitely NOT opinion, and is fairly rigorously peer reviewed. This is why on the top of the pages 2k article, it states ‘progress article’ on the top!

This is hilarious fantasy.
 
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Again we see that the way to reproduce Mann's results is to reproduce his errors.

[h=2]PAGES2K: North American Tree Ring Proxies[/h]Oct 24, 2018 – 1:57 PM
The PAGES (2017) North American network consists entirely of tree rings. Climate Audit readers will recall the unique role of North American stripbark bristlecone chronologies in Mann et al 1998 and Mann et al 2008 (and in the majority of IPCC multiproxy reconstructions). In today’s post, I’ll parse the PAGES2K North American tree ring networks in both PAGES (2013) and PAGES (2017) from two aspects:

  • even though PAGES (2013) was held out as the product of superb quality control, more than 80% of the North American tree ring proxies of PAGES (2013) were rejected in 2017, replaced by an almost exactly equal number of tree ring series, the majority of which date back to the early 1990s and which would have been available not just to PAGES (2013), but Mann et al 2008 and even Mann et al 1998;
  • the one constant in these large networks are the stripbark bristlecone/foxtail chronologies criticized at Climate Audit since its inception. All 20(!) stripbark chronologies isolated by Mann’s CENSORED directory re-appear not only in Mann et al (2008), but in PAGES (2013). In effect, the paleoclimate community, in apparent solidarity with Mann, ostentatiously flouted the 2006 NAS Panel recommendation to “avoid” stripbark chronologies in temperature reconstructions. In both PAGES (2013) and PAGES (2017), despite ferocious data mining, just as in Mann et al 1998, there is no Hockey Stick shape without the series in Mann’s CENSORED directory.
PAGES2K references: PAGES (2013) 2013 article and PAGES (2017) url; (Supplementary Information).
Continue reading →
 
[FONT=&quot]Michael E. Mann / Paleoclimatology[/FONT]
[h=1]You can always tell a Mann, but you can’t tell him much – why tree ring data (and climatic conclusions from it) sucks[/h][FONT=&quot]From the “we only select wood for hockey stick construction” department. Steve McIntyre comes back into the fray with a scathing review of just how crappy the tree ring proxies used by Michael Mann were (and still are), and shows without the questionable stripbark portion of the data, why no “hockey stick” appears. But even…
[/FONT]
 
From the comments in the link at #8:

". . . Near as I can tell, they’ve got a perfect record—every error, every wrong process, every data-mining method, every after-the-fact proxy selection, every piece of bad data, every bogus stripbark pine record, they have have all simply been moved from one study, to the next, to the next, without the slightest sign that they have learned from, or even noticed, their egregious errors …
 
From the link in #8:

Background: Stripbark Bristlecones and Mann’s CENSORED Directory
In our 2005 articles, Ross and I pointed out that the Mann’s hockey stick is merely an alter ego for Graybill’s stripbark bristlecone chronologies and that the contribution from all other proxies was nothing more than whitish noise. We noted that Graybill himself had attributed the marked increase in late 19th and 20th century bristlecone growth to CO2 fertilization, not temperature – a theory which was arguably a harbinger of the massive and widespread world greening, especially in dry areas, over the 30 years since Graybill et al (1985).
In a CA blogpost here, I further illustrated the unique contribution of bristlecones by segregating the additive contribution to the MBH98 reconstruction of bristlecones (red) and other proxy classes (e.g. ice cores, non-bristlecone North American tree rings, South American proxies, etc. in blue, green, yellow ). This clearly showed that (1) the distinctive MBH98 Hockey Stick shape arose entirely from bristlecones and that (2) all other proxy classes contributed nothing more than whitish noise – with their combined contribution diminishing in accordance with the Central Limit Theorem of statistics.
Ex12R8G.png

Mann had, of course, done a principal components analysis of his North American tree ring network withoutstripbark bristlecones – an analysis not reported in his articles, but which could be established through reverse engineering of his now notorious CENSORED directory – see CA post here. ) These non-descript PCs further illustrate the non-HSness of the Mann et al 1998 North American tree ring network without strip bark bristlecones.
figure4.gif

Figure 2. Plot of five principal components in MBH98 CENSORED directory i.e. without Graybill stripbark chronologies, mainly from bristlecones, but a couple of limber pines.
​
 
Jack Hays said:
From the link in #8:

Background: Stripbark Bristlecones and Mann’s CENSORED Directory
In our 2005 articles, Ross and I pointed out that the Mann’s hockey stick is merely an alter ego for Graybill’s stripbark bristlecone chronologies and that the contribution from all other proxies was nothing more than whitish noise. We noted that Graybill himself had attributed the marked increase in late 19th and 20th century bristlecone growth to CO2 fertilization, not temperature – a theory which was arguably a harbinger of the massive and widespread world greening, especially in dry areas, over the 30 years since Graybill et al (1985).
In a CA blogpost here, I further illustrated the unique contribution of bristlecones by segregating the additive contribution to the MBH98 reconstruction of bristlecones (red) and other proxy classes (e.g. ice cores, non-bristlecone North American tree rings, South American proxies, etc. in blue, green, yellow ). This clearly showed that (1) the distinctive MBH98 Hockey Stick shape arose entirely from bristlecones and that (2) all other proxy classes contributed nothing more than whitish noise – with their combined contribution diminishing in accordance with the Central Limit Theorem of statistics.
Ex12R8G.png

Mann had, of course, done a principal components analysis of his North American tree ring network withoutstripbark bristlecones – an analysis not reported in his articles, but which could be established through reverse engineering of his now notorious CENSORED directory – see CA post here. ) These non-descript PCs further illustrate the non-HSness of the Mann et al 1998 North American tree ring network without strip bark bristlecones.
figure4.gif

Figure 2. Plot of five principal components in MBH98 CENSORED directory i.e. without Graybill stripbark chronologies, mainly from bristlecones, but a couple of limber pines.
​
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Blog posts do not count as scientific evidence. When are you ever going to learn this?
 
Jack Hays said:
No. Your resort to a procedural defense to a scientific challenge is a sign of fear.
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It's not a scientific challenge. That's the whole point. It's a blog post. If it were a scientific challenge, it would be published in a peer-reviewed journal. Please try to understand the difference.
 
Surface Detail said:
It's not a scientific challenge. That's the whole point. It's a blog post. If it were a scientific challenge, it would be published in a peer-reviewed journal. Please try to understand the difference.
Click to expand...

Or at least written by...a scientist.
 
Surface Detail said:
It's not a scientific challenge. That's the whole point. It's a blog post. If it were a scientific challenge, it would be published in a peer-reviewed journal. Please try to understand the difference.
Click to expand...

More procedural defense, signaling more fear. Too bad.
 
Surface Detail said:
Blog posts do not count as scientific evidence. When are you ever going to learn this?
Click to expand...

There is no such thing as 'scientific' evidence. There is only evidence. Science isn't evidence. Science is a set of falsifiable theories. When are you ever going to learn this?
 
Surface Detail said:
It's not a scientific challenge. That's the whole point. It's a blog post. If it were a scientific challenge, it would be published in a peer-reviewed journal. Please try to understand the difference.
Click to expand...

Why don't you answer his very simple question? You keep evading.
 
Into the Night said:
There is no such thing as 'scientific' evidence. There is only evidence. Science isn't evidence. Science is a set of falsifiable theories. When are you ever going to learn this?
Click to expand...

Scientific evidence

"Scientific evidence is evidence which serves to either support or counter a scientific theory or hypothesis. Such evidence is expected to be empirical evidence and interpretation in accordance with scientific method. Standards for scientific evidence vary according to the field of inquiry, but the strength of scientific evidence is generally based on the results of statistical analysis and the strength of scientific controls."
 
Threegoofs said:
Or at least written by...a scientist.
Click to expand...

Surface Detail said:
Scientific evidence

"Scientific evidence is evidence which serves to either support or counter a scientific theory or hypothesis. Such evidence is expected to be empirical evidence and interpretation in accordance with scientific method. Standards for scientific evidence vary according to the field of inquiry, but the strength of scientific evidence is generally based on the results of statistical analysis and the strength of scientific controls."
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Procedural evasion x 2 = fear of the data.

The irony of SD's post is breathtaking, since McIntyre's presentation is purely empirical evidence and interpretation in accordance with scientific method.
 
From the link in #8:

. . . The 2006 NAS panel stated that stripbark chronologies (i.e. the Graybill bristlecone chronologies) should be “avoided” in temperature reconstructions. Although Mann et al 2008 stated that it was compliant with NAS recommendations, Mann flouted this most essential recommendation by including all 20 stripbark series isolated from the CENSORED analysis.
Because of persistent criticism over the impact of these flawed proxies, Mann et al (2008) made the grandiose assertion that he could get a hockey stick without tree rings (and thus, a fortiori, without stripbark bristlecones) – a claim credulously promoted by Gavin Schmidt at Real Climate. However, it was almost immediately pointed out at Climate Audit (here) that Mann’s non-bristlecone hockey stick critically depended on a Finnish lake sediment “proxy”, the modern portion of which (its blade) had been contaminated by modern agriculture and road construction and which had been used upside-down to its interpretation as a temperature proxy in pre-modern times. Mann was aware of the contamination of lake sediments, but argued that his use of contaminated (and upside down) data was legitimate because he could get a HS without them – in a calculation which used stripbark bristlecones. When challenged to show results without either stripbark bristlecones or upside-down mud, Mann (and Gavin Schmidt) stuck their fingers in their ears, with the larger climate community obtusely refusing to understand a criticism that was obvious to any analyst not subservient to the cause.
In the weeks prior to Climategate, I used increasingly harsher terms for the addiction of the paleoclimate community to the data-snooped stripbark chronologies, describing them as “heroin for paleoclimatologists”, with Briffa’s spurious Yamal chronology as “cocaine” (e.g. here here), occasioning much pearl-clutching within the hockey stick “community”.
 
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