Archives par mot-clé : Mann

Sheenjek, Alaska: A Jacoby-MBH Series

by S. McIntyre, Dec13, 2023 in ClimateAudit

MBH98 used three Jacoby tree ring chronologies from Alaska: Four Twelve (ak031) – discussed here, Arrigetch (ak032) and Sheenjek (ak033). Sheenjek will be discussed in this article.

In our compilation of MBH98 in 2003, we observed that the Sheenjek chronology archived at NOAA Paleo was not the same as the “grey” version used in MBH98.   While we used the MBH98 version to benchmark our emulation of the MBH98 algorithm, we used the version archived at NOAA in our sensitivity analysis, both in our 2003 article and in our early 2004 submission to Nature.  In his reply to our submission, Mann vehemently protested that the “introduc[tion of] an extended version of another Northern Treeline series not available prior to AD 1500 at the time of MBH98” “introduce[d] problems into the important Northern Treeline dataset used by MBH98”:

Finally, MM04 introduce problems into the important Northern Treeline dataset used by MBH98. Aside from incorrectly substituting shorter versions of the “Kuujuag” and TTHH Northern Treeline series for those used by MBH98, and introducing an extended version of another Northern Treeline series not available prior to AD 1500 at the time of MBH98, they censored from the analysis the only Northern Treeline series in the MBH98 network available over the AD 1400-1500 interval, on the technicality that it begins only in AD 1404 (MBH98 accommodated this detail by setting the values for AD 1400-1404 equal)

The other “Northern Treeline series” referred to here was Sheenjek chronology ak033.crn.  I checked Mann’s assertion alleging that the data was “not available prior to AD1500 at the time of MBH98”. This was contradicted by NOAA, who confirmed that the chronology that we had used had been available since the early 1990s.

In the figure below, I’ve compared three Sheenjek chronology versions:

  • the MBH98 version from 1580-1979 (plus 1980 infill);
  • the ModNegExp chronology (dplR) calculated from measurement data (ak033.rwl), which, in this case, has been available since the 1990s. It covers period 1296-1979.
  • the archived chronology at NOAA (ak033.crn). Also covering the period 1296-1979.

The issues relating to Sheenjek are different than observed at Four Twelve.

Continuer la lecture de Sheenjek, Alaska: A Jacoby-MBH Series

After 25 years, Mann’s Other Nature Trick Unraveled

by McIntyre, Nov 25, 2023 in WUWT

Stephen McIntyre has recently again fired up the seminal site for uncovering deficiencies in the works of Mann et al,

His latest post ends a 25 year mystery surrounding the famous MBH98 paper. A Swedish engineer, Hampus Soderqvist, reversed engineered the reconstruction and deduced that:

Mann’s list of proxies  for AD1400 and other early steps was partly incorrect (Nature link now dead – but see  NOAA or here).  Mann’s AD1400 list included four series that were not actually used (two French tree ring series and two Moroccan tree ring series), while it omitted four series that were actually used.  This also applied to his AD1450 and AD1500 steps.  Mann also used an AD1650 step that was not reported.

Soderqvist’s discovery has an important application.

The famous MBH98 reconstruction was a splice of 11 different stepwise reconstructions with steps ranging from AD1400 to AD1820. The proxy network in the AD1400 step (after principal components) consisted 22 series, increasing to 112 series (after principal components) in the AD1820 step.  Mann reported several statistics for the individual steps, but, as discussed over and over, withheld the important verification r2 statistic.  By withholding the results of the individual steps, Mann made it impossible for anyone to carry out routine statistical tests on his famous reconstruction.

However, by reverse engineering of the actual content of each network, Soderqvist was also able to calculate each step of the reconstruction – exactly matching each subset in the spliced reconstruction.  Soderqvist placed his results online at his github site a couple of days ago and I’ve collated the results and placed them online here as well.  Thus, after almost 25 years, the results of the individual MBH98 steps are finally available.

Remarkably, Soderqvist’s discovery of the actual composition of the AD1400 (and other early networks) sheds new light on the controversy about principal components that animated Mann’s earliest realclimate articles – on December 4, 2004 as realclimate was unveiled. Both articles were attacks on us (McIntyre and McKitrick) while our GRL submission was under review and while Mann was seeking to block publication. Soderqvist’s work shows that some of Mann’s most vehement claims were untrue, but, oddly, untrue in a way that was arguably unhelpful to the argument that he was trying to make. It’s quite weird.

Soderqvist is a Swedish engineer, who, as @detgodehab, discovered a remarkable and fatal flaw in the “signal-free” tree ring methodology used in PAGES2K (see X here).  Soderqvist had figured this out a couple of years ago. But I was unaware of this until a few days ago when Soderqvist mentioned it in comments on a recent blog article on MBH98 residuals.

The post is a long and technical one to which I cannot do proper justice, and I suggest reading the original at Climate Audit

Monday Mirthiness – Mike Mann’s Hockey Team ‘will keep those papers out somehow’

by A. Watts, Aug 28, 2023 in WUWT

Remember the famous quote from the head of the UK Climate Research Unit, Dr. Phil Jones that was laid bare in ClimateGate?

…I can’t see either of these papers being in the next IPCC report. Kevin [Trenberth] and I will keep them out somehow, even if we have to redefine what the peer-review literature is!

Dr. Phil Jones – ClimateGate emails

These guys never learn. Josh writes on Twitter:

Mikey’ The Trick’ Mann at work…Another story about ‘scientists’ trying to bury papers and evidence they don’t like. It’s Climategate deja vu. Read about it here

and here: The Climategate Gang Rides Again!


Shameless abuse of science…but then again, we know Mann has no shame, only hubris

Shock Retraction of Climate Science Paper Showing No Climate Emergency Draws Comparisons with Climategate Scandal

by C. Morrison, Aug 26, 2023 in TheDailySceptic

Shocking details of corruption and suppression in the world of peer-reviewed climate science have come to light with a recent leak of emails. They show how a determined group of activist scientists and journalists combined to secure the retraction of a paper that said a climate emergency was not supported by the available data. Science writer and economist Dr. Roger Pielke Jr. has published the startling emailsand concludes: “Shenanigans continue in climate science, with influential scientists teaming up with journalists to corrupt peer review.”

The offending paper was published in January 2022 in a Springer Nature journal and at first attracted little attention. But on September 14th the Daily Sceptic covered its main conclusions and as a result it went viral on social media with around 9,000 Twitter retweets. The story was then covered by both the Australian and Sky News Australia. The Guardian activist Graham Readfearn, along with state-owned Agence France-Presse (AFP), then launched counterattacks. AFP ‘Herald of the Anthropocene’ Marlowe Hood said the data were “grossly manipulated” and “fundamentally flawed”.

After nearly a year of lobbying, Springer Nature has retracted the popular article. In the light of concerns, the Editor-in-Chief is said to no longer have confidence in the results and conclusion reported in the paper. The authors were invited to submit an addendum but this was “not considered suitable for publication”. The leaked emails show that the addendum was sent for review to four people, and only one objected to publication.

What is shocking about this censorship is that the paper was produced by four distinguished scientists, including three professors of physics, and was heavily based on data used by the UN’s Intergovernmental Panel on Climate Change (IPCC). The lead author was Professor Gianluca Alimonti of Milan University and senior researcher of Italy’s National Institute of Nuclear Physics. Their paper reviewed the available data, but refused to be drawn into the usual mainstream narrative that catastrophises cherry-picked weather trends. During the course of their work, the scientists found that rainfall intensity and frequency was stationary in many parts of the world, and the same was true of U.S. tornadoes. Other meteorological categories including natural disasters, floods, droughts and ecosystem productivity showed no “clear positive trend of extreme events”. In addition, the scientists noted considerable growth of global plant biomass in recent decades caused by higher levels of carbon dioxide in the atmosphere.

In fact this scandal has started to attract comparison with the Climategate leaks of 2009 that also displayed considerable contempt for the peer-review process. One of the co-compilers of the Met Office’s HadCRUT global temperature database Dr. Phil Jones emailed Michael Mann, author of the infamous temperature ‘hockey stick’, stating: “I can’t see either of these papers being in the next IPCC report. Kevin and I will keep them out somehow – even if we have to redefine what the peer-reviewed literature is!”

A Brief Summary Of How ‘Global Warming’ Science Has Changed Since 1998

by K. Richard, Mar 31, 2022 in NoTricksZone

Two weeks before Dr. Michael E. Mann and colleagues published their 23 April 1998 “hockey stick” chart in Nature, a peer-reviewed journal published a paper asserting “an overwhelming majority of climate scientists” (50 out of 60) view catastrophic human-caused global warming – and even global warming itself – as an “unsupported assumption”.

At the time, satellite data indicated the lower troposphere had cooled by 0.13°C between 1979 and 1994. The Arctic had cooled by -0.88°C since the 1940s.

It was thought the IPCC had just (1995) perpetrated a “disturbing corruption of the peer-review process” in manipulating the conclusions of scientists to support favored government policies.

Internal Multidecadal and Interdecadal Climate Oscillations: Absence of Evidence Is No Evidence of Absence

by G. Müller-Plath, Nov 29, 2020 in WUWT


The present paper contributes a critical commentary on the recent finding by Mann, M. E., Steinman, B. A. and Miller, S. K (2020). Absence of internal multidecadal and interdecadal oscillations in climate model simulations. Nat. Commun. 11, 1–9.

Climate oscillations are recurring large-scale fluctuations in the surface temperatures of the oceans in connection with the atmosphere. This commentary focuses on the Pacific Decadal Oscillation (PDO, interdecadal timescale) and the Atlantic Multidecadal Oscillation (AMO, multidecadal timescale), which have been regarded as intrinsic climate drivers on the adjacent continents in numerous studies based on observations and paleoclimate reconstructions (Henley, 2017O’Reilly et al., 2017). In a recent paper, Michael E. Mann and colleagues (Mann et al., 2020, hereafter M20) fail to find a PDO signal in global measured and modeled temperatures that is statistically different from noise. They further propose that the significant AMO-like signal is mainly due to anthropogenic aerosols in the 20th century, and to statistical artifacts before. Therefore they doubt the intrinsic nature of the two oscillations. The present paper shows that M20’s results are largely artifacts themselves with issues ranging from using inadequate data and referencing improper literature on anthropogenic aerosols with regards to the AMO to inappropriately interpreting the results with regards to the PDO.