The Hockey Stick is Bad Science

I thank Con for a good debate.I don't dispute that making of the hockey stick was honestly undertaken. All those involved were, I believe, convinced they were correct. I do question the peer review process, a point that I raised in response to Con's objection that results of the Senate panel were not subjected to peer review. That objection is not to the undertaking of making the hockey stick, which was completed prior to 2000, but rather to the later corruption of the peer review process. Of course, the Wegman work stands on it's merits.Honesty was the first of four criteria Con offered for science to judged "good." I'm not sure the list is exhaustive, but I'll use it to summarize the debate. Standard Techniques were not usedThe original hockey stick paper was never reviewed by a scientist qualified to check the statistical methodology. The Senate committee investigation put the paper reviewers on record as admitting they were not qualified. No one on Mann Team was associated with anyone versed in mainstream statistics. Te hockey stick analysis relied heavily on bristlecone data, which the scientific literature states are should not be used as a temperature proxy.A panel of three expert statisticians, headed by Prof. Wegman, found that the statistical techniques used in the derivation of the hockey stick were wrong, and the critics were correct. Wegman specifically called the hockey stick "bad science."Con suggests that von Storch fond the errors "minor." He found one aspect minor, but, as Wikipedia summaries,"In late 2004 [von Storch's] team published an article in Science that tested multiproxy methods such as those used by Mann, Bradley and Hughes, 1998, often called MBH98, or Mann and Jones to obtain the global temperature variations in the past 1000 years. The test showed that the method used in MBH98 would inherently underestimate large variations had they occurred; ..." [12. http://en.wikipedia.org... Of course the Mann Team continues to dispute von Storch's assessment, but von Storch and the Senate panel are clearly the most qualified practitioners of the specialty of statistical analysis.Wegman and von Storch agreed on the result of the error in the Mann analysis. The hockey stick has a flat part showing that climate never varied significantly until the recent "blade" part of the graph. The blade part, showing recent temperature rise was not disputed; in fact proxies were not used for that part of the graph. So when Wegman says the hockey stick disappears, he means the long flat part becomes irregular. The error was that past climate variation were suppressed.In the last round, Con showed a recent revised graph in which some of the past temperature variations are shown. It's good that at least some errors have been corrected, but our debate is about the hockey stick graph presented in the 2000 IPCC report, shown in my R2, that eliminated all natural variations in climate. Note that even the more recent version of the graph does not show the last decade, when temperature have been flat.The hockey stick does not show robust findingsThe purpose of the hockey stick graph was to show that there had been no natural variations in climate for a thousand years and that CO2-induced global warming was causing an exponential increase in temperatures. The result allegedly showed that mankind was facing a climate crisis requiring immediate government action. The hockey stick theory was subsequently tested by comparison the temperatures that occurred subsequent to it's publication in 1998. It failed completely. Temperatures were supposed o increase exponentially, but they bounced around a constant level. If there was any trend at all it was slightly downward. As a work of analysis, McKitrick and Wegman and others showed that putting trendless noise into the hockey stick processing produced a hockey stick. A "robust" method, in scientific terms means that the method works accurately under a variety of conditions, When the supplied data has to trend, it should not produce one. that's inaccurate. therefore is fails as an analytical technique.Con maintains that Medieval Warm Period and the Little Ice Age might be compatible with the hockey stick. The idea s that they might have been local events, akin to weather rather than climate. he hockey stick purports to show that whatever natural forces affect climate, they have not operated for a thousand years. But the MWP and the Little Ice Age are documented to have persisted over very large areas for hundreds of years. More studies show they were worldwide. The hockey stick was not reproducibleMann fought to keep both the data and the processing method secret. Good science requires tat both be given to other scientists so the results can reproduced. With enormous pressure, Mann gave up much of his data and enough clues about the processing method so that other could show the errors in the method. the exact processing algorithm is stills as proprietary to the investigators.Another test of how robust the findings are is to apply standard principle component analysis to the data and see if the hockey stick emerges. It does not. Con claimed that because others on the Mann Team have produced hockey stick results, the results are reproducible. McKitrick showed that in fact the results were not independent, but relied on the e faulty tree ring data and faulty processing techniques.What is happening is not dishonesty, but rather "group think." Each person the Mann Team believes their analysis to be correct and they confirm each other in that opinion. It's a mild version of adherence to a religious doctrine by a core group of believers; none are dishonest, but they cannot be impressed by any objection. Con charges that Wegman working on finding the closeness of the group first, then applied it to the critique. It was the other way around. The Network Analysis was subsequent to the Senate Committee work, as the dates on the references show. What the network analysis a likely reason for the mutual confirmation of bad science, not the fundamental errors which were previously revealed.Comparing ExpertsExpert opinion is critical to the evaluation of this debate. It is not the case that when scientists disagree, one is free to choose who to believe. Science is highly specialized, and statistics is difficult specialty. McKitrick, Wegman and the other two panellists on the Senate committee and von Storch are level of expertise available in the subject. While Mann et al use statistical methods, they neither had expertise themselves nor did they not seek it in review. (I seek a colorful analogy. Mann vs. Wegman is like Gilbert Godfried vs. Chuck Norris or the Girl Scouts vs. the Oakland Raiders or ... never mind.) Wegman was distinguished as president of the American Statistical Association, Von Storch received the IMSC achievement award at the International Meetings on Statistical Climatology in Edinburgh in 2010, to "recognize his key contributions to statistical downscaling, reconstruction of temperature series, analyses of climatic variability, and detection and attribution of climate change." [12]Con can do no more than to quote the arguments made by the Mann Team as to why they are correct and the experts are wrong. As noted, a degree in climate science doesn't require a single course in statistical analysis.SummaryCon says that the problem I have with the hockey stick is that it doesn't show what I want it to. The problems I have are that the data and algorithms were concealed, it was not peer reviewed by qualified statisticians, it has been found to be incorrectly derived by six highly qualified experts in statistics. It also found by experts to make hockey sticks out of trendless noise, and to suppresses past climate variations. Most importantly, it's prediction of an an exponential rise in temperature in the past decade was completely false. That makes it bad science.