Wood Romances

In a previous post I gave my rebuttal to a common objection to climate science that there is no global average temperature (or that it's incalculable or meaningless). At the time I was unaware of a paper published by Essex and McKitrick[1] on the subject, published in 2007 (hereafter EMA07). I've since read it, and while I don't think my previous post needs to change in response to it, I do think it may be worthwhile to update that post with responses specifically tailored to this paper. Others have already responded this paper (it's 18 years old), most notably at RealClimate and Rabett Run , and they do a thorough job of responding to the more technical aspects of this paper. I don't think I can add anything here that you wouldn't be better served reading there, but I do have a couple thoughts about this that I think would be helpful. Averaging Intensive Variables The main argument of this paper appears to be centered on the distinction between two types of v...

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...

  This is part 2 of a series on the Hockey Stick (updated 1/8/2025 to correct statements I made about the scale of a graph). Here's part 1 . When Mann and his colleagues were constructing their proxy reconstruction for NH temperatures for their MBH98 paper, there were two significant challenges that had to be addressed. The first was calibrating proxy model to the instrumental record. They can't expect that the proxy data would match the instrumental record with absolute precision, so if they over-calibrated the model, the proxy would fit the instrumental record but would not reconstruct earlier temperatures. Random noise in the proxy and instrumental data will make the proxy data less reliable in reconstructing the past. So the challenge was to fit the overall climate trends in the proxy data to the instrumental record while allowing for variability between the two datasets. The second challenge was to address the clustering of climate proxies so that one set of proxies doesn...

After Michael Mann and his colleagues (MBH) published their first "hockey stick" paper in 1998[1] and its follow up in 1999[2], scientists had compelling evidence that recent warming, especially warming following 1950 or so, was unique in recent centuries. Geological evidence revealed that recent increases global and NH temperatures were detectable at rates beyond the natural variability observed over the last several hundred years. The resulting "hockey stick" graph was used in the IPCC's third assessment report, and the contrast between this graph and the previous schematic in the 1990 report was visually evident. The 1990 schematic was not a true reconstruction of global or even hemispheric temperatures; it was indistinguishable from a reconstruction Central England temperatures published in Lamb 1965. The 1990 graph was only a schematic with no temperature scale, and it ended in ~1950. The MBH "hockey stick" reconstruction was the first time the IP...