Letter to Dr Pachauri concerning A. Barrie Pittock's book
Climate Change: Turning Up the Heat

Ian Castles

8 November 2005

Dr. Rajendra Pachauri,
Intergovernmental Panel on Climate Change (IPCC)


Dear Dr. Pachauri,

I am writing to object in the strongest terms to your action in contributing the Foreword to the book Climate Change: Turning Up the Heat, by A. Barrie Pittock, which was released by CSIRO Publishing on 13 October, and to a number of the statements you have made in that Foreword.

The role of the Panel of which you are the Chairman is "to assess on a comprehensive, objective, open and transparent basis the scientific, technical and socio-economic information relevant to understanding the scientific basis of risk of human-induced climate change, its potential impacts and options for adaptation and mitigation". Until the Panel's Assessment Report is released, which I understand will be at a press conference on 2 February 2007, I do not think that you should have given your imprimatur to the debatable views of an individual scientist, however eminent he may be in his area of specialisation.

CSIRO Publishing has promoted the book as an authoritative and reliable assessment of climate change issues, and in support of this position has used the following extract from your Foreword in its blurb:

    For sheer breadth and comprehensiveness of coverage, Barrie Pittock's book fills a unique void in the literature in this field ... climate change is a challenge faced by the global community that will require unprecedented resolve and increasing ingenuity to tackle in the years ahead. Efforts to be made would need to be based on knowledge and informed assessment of the future. Barrie Pittock's book provides information and analysis that will greatly assist and guide decision makers on what needs to be done.

According to the blurb, the book will be read by "Those interested in environmental issues, students in environment courses, policy makers [and] those confused by the controversy surrounding climate change and needing a scientific viewpoint."

Dr. Pittock states that "In countries such as the US and Australia, where strong federal action on climate change is lacking, some state and local governments are leading the way on emissions reductions programs." My reading of statements by the Australian Government and the responsible Ministers suggests that the Government does not agree with Dr. Pittock's assertion on this matter, but in any case it is Dr Pittock's viewpoint, not a "scientific viewpoint." Moreover, it is the Australian Government which is a member of the Panel that you chair, not state and local governments. In your position, you should not characterise a book in which such statements are made as one which "provides information and analysis that will greatly assist and guide decision makers on what needs to be done".

In my own area of expertise, Dr. Pittock's book is poorly researched and will only serve to create further confusion in the debate about emissions scenarios which has arisen as a result of the IPCC's failure to follow the internationally recognised System of National Accounts to which Australia and most other Panel members are signatories. He says, for example, that "Some critics have argued on technical grounds, related to how currency exchange rates between countries are calculated, that the high emissions scenarios are unrealistic" (p. 51, emphasis added).

The critics are identified in Dr. Pittock's Supplementary references and notes (SRN, published electronically by CSIRO Publishing, with a link provided in the book) as Castles and Henderson. As you were present at the IPCC Expert Meeting in Amsterdam in January 2003 when I made my presentation on the Panel's scenarios, you know that my criticism focused on the lowest of the 35 emissions scenarios modelled by the IPCC. Dr. Pittock is therefore mistaken in believing that the criticisms relate specifically to the high emissions scenarios.

In fact, I specifically referred to the projections analysed by Dr. Tom Wigley earlier in the Expert Meeting, identifying the B1T MESSAGE scenario, with a projected CO2 concentration of 480 parts per million (ppm) in 2100, as being the extreme low scenario "in terms of the 2100 forcing pattern". I then gave a number of reasons, amplified in a subsequent paper, why this scenario "does not by any means establish a reasonable lower bound."

Unfortunately, the IPCC published no report on the meeting, and I can only assume that Dr. Pittock has not read the Castles and Henderson papers (although they are cited in SRN, together with the responses by "Nakinovic (sic) and others", and "Grubler and others"). I must also assume that he has not understood the findings of the IPCC Special Report on Emissions Scenarios. Here is an extract from his concluding chapter:

    It is worth reminding ourselves that in the range of scenarios for future emissions to 2100 in the ... SRES, one scenario (B1) resulted in emissions that would lead to less than 550 parts per million (ppm) of carbon dioxide equivalent by 2100. This scenario was based on a hypothetical world with an emphasis on global solutions to economic, social and environmental sustainability, but with no overt climate change policies. So even the authors of the SRES report agree with the authors of Natural Capitalism that it is plausible, and even desirable, to follow a safe emissions pathway in the twenty-first century for reasons other than climate change (p. 286, emphasis added)

First, on a point of fact, there is not one scenario that leads to less than 550 ppm of CO2 equivalent in 2100: there are four. In addition to the B1 IMAGE scenario which is the marker scenario identified by Dr. Pittock, there are the B1 MESSAGE, B1 MINICAM and B1T MESSAGE scenarios, all of which have lower levels of cumulative CO2 emissions between 1990 and 2100 than B1 IMAGE (the B1 MARIA scenario also has lower levels of cumulative CO2 emissions during this period, but was not included in the IPCC analysis of projected GHG concentrations and temperature increases because this scenario did not include projections of all GHGs required to force climate models).

Secondly, Dr. Pittock has failed to grasp the significance of the points to which I have added italics. Of course the SRES authors agree that it is desirable to follow a safe emissions pathway but, according to the projections in these four scenarios, this does not require any policies or actions to be taken for climate change reasons. Dr. Pittock's confusion on this point is most evident in the following passage:

    We may well ask, however, if the very low emissions in the B1 scenario are likely without policy action to limit climate change... I doubt it, but that is what the advocates of business as usual would have us believe (pps. 213-14, emphasis added).

As already noted, the projections in the B1 scenario explicitly assume that there would not be policy action to limit climate change (e.g., like all of the scenarios, it does not assume implementation of reductions under the Kyoto Protocol). And they are not "very low". The present atmospheric CO2 concentration is about 375 ppm and the projected increase to 2100 under B1 is 175 ppm. The projected increase under B1T MESSAGE, which Dr. Pittock ignores, is 105 ppm. Moreover, in its submission to the IPCC on the scoping of AR4 (March 2003), the Australian Government proposed that the Panel consider developing a scenario that may have led to a lower level of projected CO2 concentrations than B1T MESSAGE:

    The scoping process and workplan for the AR4 needs to determine whether the SRES provides a robust basis for meeting all of the emissions scenario requirements of the AR4... The process will need to ... consider whether there are plausible emissions scenarios outside the range indicated in the SRES and if so, manage integration of such scenarios into the AR4 (for example, consider developing a further scenario with lower developing country growth than the B1 scenarios, but without the high population and slow rate of technology growth associated with the A2 and B2 scenarios).

As you know, the IPCC decided on your recommendation that the scenarios developed in the late 1990s should be used again in the next assessment, and that a scenario along the lines suggested by the Australian government would not be developed.

All of this is a separate matter from the possible implications for emissions of the failure of the SRES modellers to measure output correctly. In his "Acknowledgements", Dr. Pittock thanks 10 experts from CSIRO, but it is only too clear from his discussion of this issue that he has not consulted any economists. In SRN he attributes to Nigel Arnell and collaborators (2004) the statement that "there is little difference between GDP calculated using MER and PPP after 2050, although before then the rich OECD countries appear to be less relatively rich using MER, and the rest of the world relatively less poor." In fact Arnell et al. say the exact opposite to this - and their analysis is in any case based on the "worse than useless" data that I warned would mislead researchers in my presentation to the Expert Meeting in January 2003.

With best wishes


Ian Castles
Visiting Fellow
Asia Pacific School of Economics and Government
The Australian National University

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