Climate Change: A Natural Hazard?: Book Launch Address

John W Zillman
President, Australian Academy of Technological Sciences and Engineering

The publication of Bill Kininmonth's book ('Climate Change: a Natural Hazard' by William Kininmonth, Multi-Science Publishing, Essex, UK, 2004, 207 pp) provides a timely opportunity and, to some extent also, an obligation on the expert climate community to canvass afresh the basic messages that emerge from the science of climate change.

The Australian Academy of Technological Sciences and Engineering (ATSE) is committed to fostering informed debate on important national issues in science and technology and has done a lot of work on the climate change issue over the past decade. As President of the Academy, I am pleased, therefore, to open the debate on Bill Kininmonth's book with a few observations on the science of climate change, on the use of the science in policy formulation and, most importantly, on the theme and content of the book.

I must say, at the outset, that when Hugh Morgan phoned me with the proposition that I might launch Bill's book, I felt some reservations. It was only when he added that "you don't have to agree with it to launch it" that my reservations receded just enough to make it seem like a good idea at the time. As it turned out, Hugh's advice was both insightful and helpful because Bill has written a provocative book and, despite the strength and clarity of its message, its readability and its value as a guide to some of the basic science of climate, there are significant parts of it with which I strongly disagree.

There is of course no shortage of competent people, these days, providing expert comment on the science of climate change:

• The first group is the largest and probably the most boring. It is the mainstream climate community who understand the science pretty well and believe that they have an obligation to present a balanced view of what is known and what is not known in language that can be understood by the non expert. They try to present an objective assessment of both the certainties and the uncertainties and inevitably leave those who are looking for an unequivocal 'is it' or 'isn't it' feeling rather frustrated ;
• The second group are the fervent believers who have become so convinced that, without drastic action, the world is headed towards climatic catastrophe, that they feel bound to do whatever it takes to get the message across to governments and the community. If they---the fervent believers turned greenhouse zealots---have to dramatise a bit to make people pay attention, they see that as justified by the seriousness of the threat;
• The third group are the committed sceptics who are convinced that the greenhouse zealots and even the mainstream scientists have got it wrong, and who feel bound to caution against precipitate action that might impose large costs on the community for addressing what they (the sceptics) believe to be, almost certainly, a non-problem.

There is also, of course, a much larger group of well-intentioned non-expert commentators who have become sufficiently convinced by the arguments of the greenhouse zealots, or the sceptics, that they feel bound to weigh in, in support of one side or the other; and another group, again, who have vested interest in climate change mitigation action, or inaction, and who feel justified in championing the science that supports their interests and discrediting that which does not.

For my part, I believe very strongly that the role of the climate science community is to present the state of the science as accurately and objectively as they can without either over- or understating the level of confidence or the seriousness of the risk. I have thus become very committed to ensuring the integrity of peer-review mechanisms such as the Intergovernmental Panel on Climate Change (IPCC) that are aimed at providing governments and the community at large with policy-neutral assessments of the state of the science. I can understand those whose interests the science does not support seeking to discredit its conclusions but I have some difficulty when those in the scientific community, from whom the community-at-large is entitled to expect objectivity, use their scientific credibility to promote a policy agenda by selective interpretation of the science.

How then do I view Bill Kininmonth's book which, after a distinguished 40-year professional career in climate, he tells us "demonstrates that the simple model of the climate system represented by the IPCC is inadequate as a foundation for future planning".

Let me start with the title. However provocative it was intended to be, I do not think there is anything wrong with the title of the book. If one adopts the definition of 'climate change' used by the IPCC (ie 'climate change' includes both natural variability and human induced change) rather than that of the Framework Convention on Climate Change (FCCC) (viz 'climate change' is only that part of the change which is due to human influence) there is little doubt that one of the most dangerous natural hazards we face is, indeed, climate change. We have only to recall the impacts of the Federation Drought on early twentieth century Australia, the 'dust bowl' years in the United States or the prolonged drought in the African Sahel in the 1960's and 70's to grasp the scale of the hazard. But even if Bill and his publishers were being cute in their choice of title, this is much more than terminological nit-picking; because, when the IPCC reports that the climate has changed, this does not, in any way, rule out the possibility that the change may be due entirely to the natural variability that Bill, appropriately in my view, emphasises so strongly in his book. Attributing the observed change to greenhouse or some other cause is a much tougher scientific problem as the IPCC has made clear. Unfortunately, however, when most people hear that the IPCC says the climate has changed they are encouraged (by almost everyone, including Bill) to interpret this as the IPCC claiming that humans have changed the climate and by many (also including Bill) to then rise in indignation that such a claim should be made with so little firm scientific evidence.

In turning, now, to the content of the book, I would like to begin by mentioning a few key points of agreement. Bill, as I understand him, believes that:

• The earth's climate system is exceedingly complex with natural variability on many time and space scales. I agree and so does the IPCC.
• There is a natural greenhouse effect in the atmosphere and, other things being equal, more greenhouse gases means a stronger greenhouse effect. I agree and so does the IPCC.
• The concentration of carbon dioxide and other greenhouse gases in the atmosphere has been increasing over the past century. I agree and so does the IPCC.
• Climate records clearly identify a warming trend at the surface, around the globe during the 20th century. I agree and so does the IPCC.
• It is essential to take account of the full three-dimensional structure of the atmosphere and ocean and the physical processes that lead to variability and trends on all time scales when building predictive models for the global climate system. I agree and so, I am sure, does the IPCC.
• There is a need to build both a better understanding of past variations of climate and improved predictive tools if we are going to prepare for the future. I agree and so, I am sure, does the IPCC.

Where we begin to diverge is that I believe the models are now remarkably good at simulating most of the essential climate forming processes in the atmosphere and the ocean and even the behaviour of the total climate system at the global scale. And, though I would not have said so a decade ago, I now believe, as does the IPCC, that there is no more than a one in three chance that the observed global warming over the past century is entirely natural in origin.

I would like to say a few words about the book's interpretation of the debate on global temperature trends on the basis of both proxy and instrumental data over the past thousand years and Bill's sense of outrage at the conclusion in the IPCC's Third Assessment Report in 2001 that "the increase in temperatures in the 20th century is likely to have been the largest of any century during the past 1000 years". I am sure that the scientific debate on the so-called 'hockey stick' and the interpretation of both the proxy and instrumental records will go on for years but, given that the IPCC Lead Authors were very careful to say only that they were confident that there is at least a 66% chance that the past century has been the warmest of the past millennium, I believe that his outrage is misplaced and his summary dismissal of the IPCC conclusions as 'unreliable' is, to use his own word, a little simplistic.

Let me come, now, to the major thesis of Bill's book: that the treatment of the essential physics of the climate system, in the IPCC's Third Assessment Report, is inadequate for the purposes of assessing the impact of greenhouse gas increases on global climate and that "The evidence advanced by the IPCC, that human activity will cause dangerous inference with the climate system, is illusory". I offer just three observations:

• Bill appears to have difficulty with the concept of focussing on the impact of an enhanced greenhouse effect on the vertical temperature structure of the atmosphere (and thus on surface warming) in terms of global integrals or averages---the so-called one dimensional model of the heat budget of the atmosphere and ocean. He seems to believe that this somehow overlooks the role of all the horizontal energy transfer processes (especially between the equator and the poles) that he correctly regards as an integral part of the working of the climate system.
• I believe his concern is misplaced and that he is almost alone in the climate science community in not acknowledging the value of the one-dimensional radiative forcing framework as a useful pedagogical tool for summarising the essential output of the three-dimensional global climate models that build in all the physical processes he believes are important.
• I firmly believe that these are issues that Bill should have been debating with the relevant scientific experts. In line with the long-standing advice of one of Australia's most respected atmospheric scientists, the late Dr Bill Priestley of CSIRO, I support vigorous debate on such complex and controversial issues within the scientific community but I believe we should exercise great care and balance when communicating the state of the science to the community at large. These are not, in my view, issues that are likely to be clarified by assertions in books intended for the non-expert general reader or by reviews of such books in the popular press and certainly not by book launches such as this one.

While I can understand, and to some extent share, Bill's frustration with the faith that is sometimes placed in the output of global climate models---including the significance of agreement amongst models---and especially in their capacity to indicate possible future REGIONAL patterns of climate change, it is important to note that, in this respect, he is not alone in his concern. The IPCC Third Assessment Report itself goes to considerable lengths to stress the limitations of current models especially in respect of their ability to indicate future regional patterns of climate change.

For my part, I believe it unlikely that even the best models are yet sophisticated enough to capture all the processes that will determine where and how frequently significant rain-producing events will occur in a greenhouse-warmed world. I also believe that we have , as yet, so little skill in predicting the natural variability of climate on decadal to centennial timescales that we simply cannot say how the patterns of natural and human induced change might cancel or reinforce each other at the regional and local level over coming decades and centuries.

If Bill Kininmonth's purpose in emphasising the limitations of the global climate models was to caution against taking their output too much on faith, and to focus attention on the need to improve them, I think he is playing a useful role and one which I fully support.

But I believe that Bill goes much too far and, for whatever reason, misinterprets and/or misrepresents some important aspects of the science of climate change that are now pretty well understood. At least thirty times in the book he asserts, albeit in slightly different language in each place, that what he refers to as the one-dimensional IPCC construct of radiative forcing of climate change is fundamentally flawed. He makes much of the well known three-dimensional structure of atmospheric processes and energy flows in the climate system and implies that these have been overlooked by the IPCC. I offer two specific comments on Bill's characterisation of the IPCC:

• The IPCC is not, as Bill implies and many appear to have been lead to believe, some ideologically committed group of scientists with a particular position or perspective on the science which they seek to promote. Rather it is a highly transparent process, supervised by governments, which enables the contemporary state of knowledge of climate change as it emerges from the peer-reviewed published literature to be summarised and assessed by a representative group of the internationally acknowledged experts in the field with their summary assessment subject to one of the most exhaustive processes of peer review and revision that I believe has ever occurred in the international scientific community. The IPCC doesn't have a construct, a model, an ideology or a pre-determined position. It is simply an inter-governmentally coordinated scientific assessment mechanism for producing in summary form, for use by policymakers, a synthesis of the state of the science as it appears in the literature with particular attention to the identification of points on which there is a high level of scientific agreement in the literature and those on which there is little agreement or little confidence in what is agreed.
• Bill is wrong to assert or imply that the model results on which the IPCC assessments are based don't take account of all the various three dimensional energy transfer processes that he argues are so important. He is seriously misleading in his belittling as 'one-dimensional' of the IPCC's use of globally averaged versions of the energy budget (which, have the tremendous advantage of making it possible to focus in on only those considerations that capture the essential physics of global warming---the enhanced greenhouse effect) as a pedagological device for helping non-experts to understand the basic mechanisms of global change.

It has not been my intention here to try to produce any sort of scientific review of Bill's book. But I believe it is very important that the expert scientific community does review it very thoroughly and helps to clarify the issues that have caused Bill so much concern---rather than just ignore it as the product of ideology or misreading of the IPCC reports. By the same token, however, I think it is a shame that, before writing his book, Bill did not try to test his interpretation of the science through publication of his criticism of the IPCC methodology and conclusions in the peer-review literature.

So is the Kininmonth book on Climate Change itself something of a natural hazard---for those who want to believe that greenhouse isn't an issue and who will gain false reassurance from its strident criticism of the IPCC conclusions; or, for that matter, for those who share his concern with better understanding the natural variability of climate and who will see his important message about the need to focus on planning for future natural changes in climate at risk of being discredited as no more soundly based than his interpretation of the science of global warming? I think not because, with the IPCC Fourth Assessment Report now underway and due for completion in 2007, it is important that all perspectives be properly heard and debated before the essential conclusions of the next assessment get set in concrete. I hope, however, that, if Bill decides to produce a second edition of his book, he will recognise that one doesn't have to dismiss almost everything that is understood about greenhouse warming in order to make the case for the importance of the natural variability of climate; and that he will see no need to characterise as 'nonsense', 'bizarre' or 'beggaring belief' the consensus judgements of the mainstream scientific community on the contemporary state of knowledge of anthropogenic climate change and allow his book to be what a book titled 'Climate Change: A Natural Hazard' written for a general audience, could usefully be---a timely exposition of the importance for humanity of the large, and still largely unpredictable, natural variability of climate on timescales from decades to centuries, millennia and beyond.

I would, of course, be delighted to launch such a book for him---without reservations of any kind.

In the mean time, I wish him well and hope that the publication of his book will trigger the kind of debate that will lead to more long-term enlightenment than short-term heat. I have great pleasure in declaring Bill's book on 'Climate Change: A Natural Hazard' launched.

22 November 2004

To read the author's launching speech for Climate Change: A Natural Hazard, please click here

For details of how to order Climate Change: A Natural Hazard, please click here