Monday, 28 June 2010

Statistical Shenanigans & the IPCC’s Assessment Reports

Politicians are fully familiar with the phrase “Lies, damned lies and statistics” (the origin of which has been attributed to the UK politician Benjamin Disraeli – Note 1) and frequently use the powers of statistical manipulation to distort facts in order to support whatever argument they are using at any particular time.

It is clear to anyone who has spent time researching The (significant human-made global climate change) Hypothesis that statistical manipulation plays a major role in trying to unravel the enormous uncertainties underpinning our poor understanding of the extremely complex (almost chaotic) processes and drivers of global climates. This lack of clear understanding is acknowledged by scientists who are involved in climate research and in advising politicians about it. A good example is given by Adelaide University’s Professor Barry Brook (a biologist), Director of Climate Change Research (Note 2) in his criticism of the book “Heaven and Earth” (Note 3) by his sceptical Adelaide associate Professor Ian Plimer, Professor of Mining Geology.

This disagreement between a biologist and a geologist at the same university appears to be representative of a wider level of disagreement between those two disciplines. A 2008 poll by The Association of Professional Engineers, Geologists, and Geophysicists of Alberta, Canada (Note 4) found that QUOTE: .. A 99-per-cent majority believes the climate is changing. But 45 per cent blame both human and natural influences, and 68 per cent disagree with the popular statement that “the debate on the scientific causes of recent climate change is settled.” .. UNQUOTE.

Experts within statistics and paleoclimatology, two more of those numerous disciplines that are contributing to improving our understanding of the processes and drivers of global climates, have disagreed vigorously for years. A significant part of this debate is about the validity of the statistical manipulations used by paleoclimatologists to reconstruct global temperature conditions during the past 1000 years. A graph of such by paleoclimatologist Michael Mann was prominently displayed in numerous places in the IPCC’s Third Assessment Report. Significant support for the results of this and subsequent attempted reconstructions by paleoclimatologists considered to be part of Mann’s “hockey team” using similar data and statistical methods as Mann was still given in the 4th Assessment Report.

On the other hand scant consideration was given to the arguments of expert statisticians Steve McIntyre and Ross McKitrick. These arguments were fully supported by a USA inquiry in 2006 by a team of statisticians chaired by recognised expert Edward Wegman (Note 5). A detailed study of this issue is given in “The Hockey Stick Illusion” by Andrewe Montford of Bishop Hill blog fame (Note 6) which presents the facts behind the efforts by “The Hockey Team” to get rid of the Medievil Warm Period and the Little Ice Age through the use of inappropriate statistical manipulations. It’s well worth reading and you may be interested in the interview that he gave with The Register (Note 7) around the time of its publication. Also of interest are the reviews of the book available at Amazon (Note 8).

Another enquiry held this year in the UK into the “Climategate” scandal (the leaking of the University of East Anglia E-mails between members of the “hockey team”) included one statistician and concluded with the understatement (Note 9) QUOTE: .. We cannot help remarking that it is very surprising that research in an area that depends so heavily on statistical methods has not been carried out in close collaboration with professional statisticians. Indeed there would be mutual benefit if there were closer collaboration and interaction between CRU and a much wider scientific group outside the relatively small international circle of temperature specialists .. UNQUOTE. In this area, where statistics plays such a major role, the involvement of expert statisticians has been shown to be an essential requirement, not only as members of teams undertaking the original research but also in teams involved in the auditing of the reports of such work.

Political and scientific supporters of the UN’s IPCC appear to have perfected the art of statistical manipulation in their attempts to convince us that our use of fossil fuels as a source of energy is causing significant (leading to catastrophic) global climate change. This is amply demonstrated in the IPCC’s 3rd and 4th assessment reports in 2001 and 2007. The IPCC is presently gearing up for its 5th assessment report (Note 10) with the following representatives being nominated for Chapter 5: Information from Paleoclimate Archives.
Coordinating Lead Authors:- Valerie Masson-Delmotte (France) and Michael Schultz (Germany);
Lead Authors:- Ayako Abe-Ouchi (Japan), Juerg Beer (Switzerland), Andrey Ganopolski (Germany), Jesus Fidel Gonzalez Rouco (Spain), Eystein Jansen (Norway), Kurt Lambeck (Australia), Juerg Luterbacher (Cyprus), Tim Naish (New Zealand), Timothy Osborn (UK), Bette Otto-Bliesner (USA), Terrence Quinn (USA), Rengaswamy Ramesh (India), Maisa Rojas (Chile), Xue Mei Shao (China), Axel Timmermann (USA).
Review Editors:- Fatemeh Rahimzadeh (Iran), Dominique Raynaud (France), Heinz Wanner (Switzerland), De`er Zhang (China).

Although there are numerous names above that are familiar to anyone who has followed the “Climategate” scandal I cannot identify any expert statisticians among these so it looks as though the IPCC has chosen once again to ignore the advice of experts when preparing its assessment reports. While looking unsuccessfully for evidence of any expert statisticians being involved in the 5th assessment report I did come across an interesting comment relating to review editor Heinz Wanner (Note 11) QUOTE: .. Climate has changed substantially since the last Ice Age. Heinz Wanner will present the changes that have been deduced, and how these changes can be inferred from natural archives of past climate change. This indirect evidence records climate changes and other influences, and hence estimates of past climate change are uncertain UNQUOTE. It will be interesting to see how Dr. John Haslett (Note 12), Professor of Statistics, Department of Statistics, Trinity College, Dublin (and a Chartered Statistician I believe) QUOTE: .. explains how to explore and quantify the uncertainty .. UNQUOTE.

John Haslett would appear to be an ideal candidate for inclusion by the IPCC as one of its lead authors for Chapter 5 and I’m puzzled as to why the IPCC has not nominated him as an expert author for the 5th assessment report. Maybe it’s because he’s not a signed-up member of the Mann “hockey team”. When talking in his 2010 paper “Palaeoclimate Histories” (Note 13) about statistical manipulations relating to the “hockey stick” Professor Haslett discusses my favourite topic – uncertainty. QUOTE: .. Uncertainty in the discussion of climate is inevitable. But ignoring it – or using over-simple methods – is not. Modelling uncertainty (and indeed communicating it) is neither simple nor cheap; however it cannot be set aside. In fact, confidence about the handling of uncertainty not only pre-empts the sometimes sterile debate encouraged by unqualified (or poorly qualified) statements about climate change, past and future; but it goes further. It provides a basis for pooling the many different sources of information and thus for reducing the uncertainty associated with at least some statements. In this paper we discuss some of the challenges and look forward to the fruits of recent developments .. UNQUOTE.

I understand that to be expert statistician Professor Haslett confirming that earlier attempts to reconstruct past global climates are highly suspect and that much more research is required before worthwhile conclusions can be drawn and used as the basis for policy decisions by politicians – but I would think that wouldn’t I, because I’m a sceptic.

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Best regards,

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