On the “Hockey Stick” and the carbon tax

A great article by Steven Hayward in the Weekly Standard on the history of the “hockey stick,” its influence and the problems surrounding the same. He also uncovers more emails that reveal infighting among the group, and attempts made at eliminating the MWP (“medieval warm period”) from the graphs-

One of Briffa’s concerns about Mann’s hockey stick is that some of the tree ring data–Briffa’s specialty–didn’t match up well with other records, so Mann either omitted them (in some versions of the hockey stick) or changed their statistical weighting in his overall synthesis to downplay the anomalous results of the raw data. This, by the way, is the origin of Phil Jones’s “hide the decline” email; after 1960 tree ring data suggest a decline in temperatures, while other datasets show an increase. (This is one of many sources of intense controversy about temperature reconstructions.) Jones’s and Mann’s treatment may be defensible, but is problematic to say the least.

Starting in 2003 two mild-mannered Canadians, retired engineer Stephen McIntyre and University of Guelph economist Ross McKitrick, began making noises about serious problems with the by-then iconic hockey stick graph. The dispute between McIntyre, McKitrick (M/M as they became known in the shorthand of the climate science world) and the hockey team was highly technical, involving advanced methods of data selection and statistical analysis that are almost impossible for a layperson to follow. But one key point was access to the original raw data and complete computer codes that Mann and CRU had used, rather than the adjusted data reported in their final studies.

To extend the sports equipment simile, Mann and the hockey team responded with the scientific equivalent of high-sticking. It was McIntyre’s requests for raw data and computer codes that prompted the numerous emails from Jones and other CRU people about “hiding” behind technicalities to refuse freedom of information requests or even destroying data, codes, and emails to stymie McIntyre. Prior to this time, most of the complaints about outsiders in the leaked emails dealt with such well known skeptics as the University of Virginia’s Patrick Michaels and Fred Singer, MIT’s Richard Lindzen, and journal editors who didn’t toe the line. After 2003 the CRU crew became obsessed with McIntyre above all others. He appears in 105 of the emails by name (in some others, he’s referred to as “a certain Canadian”), usually with a tone of resentment and contempt.

McIntyre is not a climate-science insider, with peer-reviewed articles in journals that the hockey team firmly controlled. He’s an amateur with mathematical chops, with a serious track record for spotting statistical funny business. McIntyre, who spent decades in mineral exploration, was involved in exposing the Bre‑X fraud in Canada several years ago. Bre‑X was a gold mining company promising fat profits on a new proprietary technology for ore deposits in Borneo; McIntyre smelled a rat and demanded the raw data. Bre‑X collapsed shortly after. And McIntyre scored a major hit against NASA’s chief climate alarmist James Hansen, discovering significant errors of overestimation in Hansen’s temperature reconstruction of the 20th century. (NASA’s Goddard Institute website publicly thanked McIntyre, no doubt through gritted cyber teeth, for pointing out their error.) The hockey stickers’ obsession with McIntyre seems out of proportion if there was nothing amiss in their work.

McIntyre and McKitrick may have made mistakes in their critique of the hockey stick–the charges and countercharges are difficult for nonspecialists to sort out–but they were sufficiently persuasive that the National Academy of Sciences appointed an expert review panel to look into the dispute. The NAS reported its findings in 2006, and the language was sufficiently hedged in diplomatic equivocations that Mann and the media claimed the hockey stick had been vindicated. But a close reading shows that the NAS report devastated the hockey stick. While the NAS said the hockey stick reconstruction was a “plausible” depiction of 20th-century warming, the report went on to state clearly that

substantial uncertainties currently present in the quantitative assessment of large-scale surface temperature changes prior to about A.D. 1600 lower our confidence in this conclusion compared to the high level of confidence we place in the Little Ice Age cooling and 20th century warming. Even less confidence can be placed in the original conclusions by Mann et al. (1999) that “the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millennium.” [Emphasis added.]

One of the NAS committee members, physicist Kurt Cuffey of the University of California, was more direct in remarks to Science magazine: “The IPCC used [the hockey stick] as a visual prominently in the [2001] report. I think that sent a very misleading message about how resolved this part of the scientific research was.” Mann’s hockey stick, a centerpiece of the 2001 IPCC report, did not appear in the 2007 IPCC report.

Bhagwati and Panagariya have a piece in the TOI arguing against the carbon tax. Its a “thoughtless tax,” they write-

[M]any fear that our industries will go abroad to exploit lower carbon tax burdens. But many studies show that the investment decision, as to where to locate, reflects several factors such as infrastructure, availability of raw materials and political stability.

The administration of carbon tariffs is also a complex task that will raise hackles. For example, in today’s interdependent world economy, most production involves importation of components and raw materials from several sources. Calculating the carbon content of a product is therefore as arbitrary as calculating the “local content” and source of origin in implementing preferential trade agreements and eligibility for cheaper market access; and, because it involves imposing tariffs rather than exemptions from tariffs, it will be more contentious and productive of disharmony.

What are the better alternatives to carbon-tax-equalising tariffs? There are several. First, the use of such carbon tariffs must be effectively ruled out…

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  • tommoriarty  On December 14, 2009 at 12:55 pm

    Here is a piece of code that tests the idea that Michael Mann’s incorrect centering of proxy data causes the Principal Componenet Analysis algorithm to find hockey sticks red noise…

    Michael Mann Averaging Error Demo

    Best Regards

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