"....A Tale of Due Diligence"

A fascinating piece from Ross McKitrick entitled "The Mann et al. Northern Hemisphere 'Hockey Stick' Climate Index: A Tale of Due Diligence" is now available online here.

This was initially published as Chapter 2 of Patrick Michaels' book "Shattered Consensus: The True State of Global Warming".

I think this piece is the best detailed, warts-and-all account of the demolition of the hockey stick, and I encourage you to read it all.

Some excerpts:

This chapter tells the story of the detective work of Stephen McIntyre (and, to a lesser extent, myself) regarding the famous “hockey-stick" climate history graph of Mann, Bradley, and Hughes (1998), better known as MBH98. After studying in detail how the hockey-stick graph was done, we found mistakes in the data and methods that went unnoticed for years, even as the graph was used by governments worldwide to drive major policy decisions. The story behind the hockey stick provides a cautionary tale about the need to recognize the limited function of journal peer review and the dangers of proceeding with major policy decisions without applying a further level of due diligence equivalent to an audit or an engineering study. It also shows that the Intergovernmental Panel on Climate Change failed to carry out elementary due diligence on its most famous promotional graphic, despite widespread perceptions that it had.
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The hockey-stick graph has been reprinted countless times and used by governments around the world as the official, canonical climate history of the world.
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...He had assumed that the IPCC and others had carried out due diligence prior to relying on this graphic and that such due diligence would have necessarily required examination of the data—drawing from his own experience with audits and business due diligence. If the data had not been so organized, was it possible that no one had ever checked the data? It was a bizarre possibility, but the collective failure of due diligence in the Bre-X (and, for that matter, Enron) collapses were just as strange.
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Thus, what was erroneously argued to be the “dominant” signal in the entire Northern Hemisphere climate turns out to have been a local phenomenon specific to a group of high-altitude bristlecone pines, whose influence was inflated due to a programming error. Mann’s hockey stick hinges (literally) on this. And on that flimsy foundation the Intergovernmental Panel on Climate Change based the conclusions of its third assessment report.
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At the IPCC level, the IPCC itself made no attempt to verify any MBH98 findings, relying only on the prior peer review by Nature. There is a common misunderstanding by the general public and the numerous Nobel laureates who endorsed the IPCC report that the IPCC carried out substantial due diligence of its own. That is not the case. Obviously, problems can result if people think that due diligence has taken place when it hasn’t.

The failure of the IPCC to carry out such independent verification or to audit studies may be partly explained by the lack of independence between the chapter authors and the original authors. Michael Mann was lead author of the chapter relying on his own findings, a lack of independence that would never be tolerated in ordinary public offerings of securities.
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...there is an obvious need for additional due diligence prior to use of academic articles in public policy. In the private sector, no one would build an oil refinery based an academic article. There is a process of engineering due diligence. Some of the most highly paid professionals are principally involved in verification. Yet governments will make far larger, costlier decisions based on the chimerical standard of academic peer review. Merely stating the contrast points to the need to ramp up standards in the public sector, and quickly.