Wood Romances

About 15 years ago a paper was published[1] that included a proxy reconstruction of extratropical Northern Hemisphere temperatures for the last 2000 years. The graph included in the paper sometimes gets adapted by contrarians to give the impression that the Medieval Warm Period was warmer than today. Here's one example: The claim is then made that this is evidence or proof that Mann's hockey stick was a fraud, and scientists like Mann were actively trying to erase the Medieval Warm Period. Of course there are a few problems with this conclusion, beginning with the fact that it appears these people haven't even read the abstract of Ljungqvist's paper: Our temperature reconstruction agrees well with the reconstructions by Moberg et al. (2005) and Mann et al. (2008) with regard to the amplitude of the variability as well as the timing of warm and cold periods, except for the period c. ad 300–800, despite significant differences in both data coverage and methodology. Rather...

WA07 Demonstrating Verification Failure of M&M This is part 3 of a 3 part series on M&M's accusations of "tricks" on the part of MBH and the hockey stick. Part 1 is here and Part 2 is here . Stephen McIntyre is reporting another "Nature Trick" on his ClimateAudit blog. The post is from Nov 24, 2023. As I've pointed out before, the MBH98/99 hockey stick have been replicated so many times that it's really old news. In 2007, Wahl and Amman were able to emulate the MBH98/99 hockey stick reconstruction and verify that it was robust to statistical method. But there were some slight differences between the two, and it seems some people won't be happy until they emulate it exactly.  An "Audit" of MBH98/99 In 2021, Hampus Söderqvist apparently succeeded in reproducing MBH98/99 exactly, but in the process of doing so, he discovered some minor errors from the infilling of grid box temperatures in Jones & Briffa 1992 that affected MBH98/99...

By 2007, the MBH98/99 papers had been thoroughly investigated. The MBH hockey stick was found to be robust to statistical method and it was replicated by multiple other reconstructions (above, and discussed  here , here and here ). After the CRU emails were hacked and published, a new set of conspiracy theories were popularized on blogs and YouTube - these were based on a misreading of various emails (discussed  here and here ), but contrarian rhetoric was ramping up to a frenzy. Mann was frequently labeled a criminal and fraud, the hockey stick was called a scam or a hoax.  The Mann v Ball Libel Suit In an interview with the Frontier Centre for Public Policy  (FCPP), Tim Ball was asked, "Various government and academic agencies have whitewashed the Climategate scandal so far. Do you think anyone will be prosecuted for fraud?” Tim Ball's response was, “Michael Mann at Penn State should be in the State Pen, not Penn State.” This was posted on the FCPP website and a...

Hockey Sticks Featured in the North Report In two previous posts ( here and here ), I described the challenges by McIntyre and McKitrick (M&M) to the initial two hockey stick papers published by Mann, Bradley and Hughes (MBH98 and MBH99). In these posts I summarized M&M's multiple critiques of the MBH hockey stick papers, essentially that the "hockey stick" is an artifact of flaws in the MBH statistical method and an over reliance on one set of North American tree ring proxies. However, multiple peer-reviewed papers following M&M's criticism generally found that M&M's criticisms lacked merit and vindicated the MBH hockey stick reconstruction. To summarize: 1. Biases associated with MBH's statistical method were small and contributed very little to the shape of the MBH hockey stick reconstruction. Biases associated with M&M's statistical method went in the opposite direction, and M&M exaggerated the effect of statistical bias on the...

Just recently I saw a video by John Robson from what he calls a "Climate Discussion Nexus." I've seen several of his videos before, and for the most part they simply put a nice-looking polish on old, debunked contrarian talking points so that you can see them with a higher production value than what you might see in a Tony Heller video. I've largely ignored most of these; John Robson is a historian, and it's pretty clear that he doesn't understand the evidence he's trying to refute. But in this particular video Robson's credentials as a historian could have served him well, if he had chosen to use his expertise to uncover the facts involved. The "Hockey Stick" as it Appeared in IPCC TAR In this video , John Robson attempts to describe the dissention between Michael Mann and his colleagues as they were preparing chapter 2 of the IPCC TAR. This chapter included the "hockey stick" graph with data from MBH99, Briffa 2000, Jones 1998, a...