In his latest book, “Heaven and Earth. Global warming: the missing science”, Professor Ian Plimer from the University of Adelaide questions the science of human-induced climate change. Here a range of Australian scientists respond to the book.
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Professor Colin Woodroffe, a coastal geomorphologist at the School of Earth and Environmental Sciences, University of Wollongong, and a lead author on the IPCC AR4 chapter on coastal systems.
Professor Matthew England, an ARC Federation Fellow, and Joint Director of the University of New South Wales Climate Change Research Centre.
Dr Graeme Pearman, an Honorary Senior Research Fellow at Monash University in Melbourne and Director of Graeme Pearman Consulting Pty Ltd.
Professor Nathan Bindoff, a physical oceanographer and Director of the Tasmanian Partnership for Advanced Computing (TPAC). Partners include the University of Tasmania, CSIRO Marine & Atmospheric Research and the Antarctic Climate and Ecosystems CRC. He was a Coordinating Lead Author of the IPCC AR4 Working Group 1 chapter on oceanic climate change and sea level observations (Chapter 5).
Professor Barry Brook holds the Foundation Sir Hubert Wilkins Chair of Climate Change and is Director of the Research Institute for Climate Change and Sustainability at the University of Adelaide.
Dr Harvey Marchant, a marine biologist and Visiting Fellow at the Australian National University and Lead Author on three of the four principal IPCC assessments.
Ian Lowe, an Emeritus professor of science, technology and society at Griffith University,Qld and President of the Australian Conservation Foundation.
Professor Colin Woodroffe is a coastal geomorphologist at the School of Earth and Environmental Sciences, University of Wollongong, and a lead author on the IPCC AR4 chapter on coastal systems.
“This is an interesting book, written in a confrontational style, and sure to create a stir. I find myself caught between feelings of admiration for what is a major undertaking putting together 500 pages of solid and articulate text, and despair that such a distinguished academic should have reached this disillusioned view of his academic colleagues. Professor Plimer has distinguished himself through his willingness to confront before, and one is left with the impression that it is the polemics rather than the science in which he takes the greatest pride with this latest volume. Plimer has set his sights on the practice of science, but rather than the ‘dispassionate criticism’ which he correctly regards as the indispensable methodology of scientific advancement, he adopts an adversarial stance, culminating in the final chapter where he insinuates that the debate has been hijacked by ‘unquestioning mantra’, ‘political dogma’, ‘religious zeal’ from extreme environmentalists and climate scientists, with the ‘demonising of dissent’.
This book is preceded by its reputation. It will be remembered for the confrontation it provokes rather than the science it stimulates. This is unfortunate because Plimer must have put an enormous amount of effort into writing it. It is an impressive treatise; it meets the first criterion of good scholarship in that it is based on a very broad and up-to-date range of scientific papers, referring to almost a couple of thousand references in the extensive footnotes. Whereas assertions in the text are supported by references, the source of data in the diagrams is frequently not cited. But the next criterion for good science is peer review (the process whereby scientific writing is critiqued by acknowledged experts in the field who scrutinise it for its integrity and veracity before publication), and the content of this book has not been independently reviewed and remains the view of Plimer himself, however omniscient a polymath he is. As a consequence, Plimer’s book has many errors in it. Below I draw particular attention to his misinterpretation of sea-level changes and their significance, and comment on his misrepresentation of the IPCC.
In discussing sea-level rise, Plimer outlines several observed rates of sea-level rise and concludes that a rate of around 1.7 mm/year is the appropriate figure derived from tide gauges over the past few decades, which he then claims is ‘far less than anything promoted by IPCC’ (p313). But this is indeed the figure that IPCC also cites as recorded by tide gauges (they actually say 1.8 mm/yr but this is indistinguishable from 1.7 at this level of confidence: see Table SPM-1). It is noticeable that never do his references to IPCC cite section or page number, and in this instance his insinuation is quite unfounded. As his comments on page 315 show, the range of sea-level projections has actually decreased over successive IPCC assessment reports, and the lower trajectory in their range of projections also corresponds to this rate of 1.8 mm/year. There has actually been publication of several papers since the AR4 that indicate that the range of projected global sea-level rise of 18-59 cm by 2100 was very conservative and observed rates appear to be following or exceeding the upper projection (widely cited studies by Stefan Rahmstorf or the comments on scientific reticence by James Hansen). One reason, spelt out by the IPCC AR4, is that ice melt is not included in IPCC AR4 projections because insufficient is known about ice dynamics, exactly the point made by Plimer (p245). Imagine the criticism that a contrarian such as Plimer would have heaped on the projections if ice melt had been included given the uncertainties associated with it!
Unfortunately Plimer’s treatment of sea level demonstrates that he has a poor understanding of what has happened. His choice of references has been selective and his description of past sea-level change is wrong. Sea level did rise rapidly during much of the postglacial, and at rates that exceed those observed now, or projected for the immediate future, but this was driven by the rapid melt of the massive ice sheets which was largely complete by around 6000 years ago. That is the basis for his statement that the sea was higher 6000 years ago (when he also claims it was 6˚ C warmer, page 238, although 2˚ C would be a more widely accepted value). Since that time, the details of the pattern of sea-level change have varied around the world because there has been relatively little ice melt; the view that there have been major oscillations over the past few thousand years is not widely held. More important though is that it is completely wrong to imply that either the modern observed rate of sea-level rise, or projected rates, are ‘exactly what would be expected at the current post-glacial sea level rise rate’ (p316). The large ice sheets that drove that rapid rise had largely disappeared by 6000 years ago and the volume of water in the oceans has changed little over recent millennia (which Plimer clearly realises as his next paragraph on that page says most of the melt occurred between 14,000 and 8,000 years ago). It is thermal expansion of seawater which appears to be driving the renewed sea-level rise, with the contribution from further melt of ice a subject of considerable debate (including by Plimer himself in this book).
The Earth has certainly seen more rapid rates of sea-level rise, and it is true that coastal ecosystems, including coral reefs, have coped, and at times flourished in response. Plimer, however, commits a series of errors when he discusses coral atolls. Although reefs can cope with rapid sea-level rise, in his discussion of atolls it is the future of the islands and the populations that live on them that are of public concern. The reefs were below water during the rapid postglacial sea-level rise; there is no evidence for any islands, and there were certainly no people on any of the atolls. Plimer is right that reefs have prospered when sea level has risen rapidly in the past and may flourish as the sea rises across modern reefs, but the inhabitants of coral atolls live on the fragile islands above sea level, and their future is much less certain than the reefs below sea level. Plimer further clouds his discussion on this issue with comments that atolls are sinking (p293); he must be aware as a geologist that the rate of subsidence is at least one order and perhaps two orders of magnitude less than the rate of sea-level rise, so this subsidence is imperceptible.
Misrepresenting the IPCC
Plimer appears especially disenchanted with climate scientists and the IPCC (the Intergovernmental Panel on Climate Change). The latter he says is a ‘political organisation’; and he goes to considerable lengths to misrepresent the IPCC and to insinuate that it is unscientific. As a lead author in the IPCC Fourth Assessment report, I particularly resent this, as doubtlessly will many hundreds of other scientists who have contributed as authors or reviewers to the process. There are three important points to make about the IPCC, which Plimer ignores. First, it is the ‘intergovernmental’ panel; it was set up by governments, in order that governments had a review of the science associated with changing climate upon which they could make decisions. It was not politically contrived; the writing was undertaken by nominated specialists across the fields, but there was an expectation that some of the issues would be spelt out in terms of levels on confidence, or degrees of uncertainty. This involved a codification where issues that were not entirely resolved (and most scientists will agree with Plimer that science is never settled) were described as ‘more likely than not’, or to some level of confidence.
Second, it is very important to emphasise that IPCC authors were not asked to produce new science or to develop new interpretations of results, but to review the literature published since the previous assessment report and in that sense the content of each chapter was constrained to cover what was already written in the published literature. In areas of concern where a particular issue had only recently received attention, for example ocean acidification, there was often very little research, and hence a limit to what an IPCC assessment could say.
Third, and particularly important, the text went out for several stages of review. The text was not just written by the lead authors and contributing authors, but went through the most rigorous process of review. At least two drafts were reviewed by other scientists, and a third was reviewed by governments. Comments that were received were documented and a paper trail kept of responses so that the greatest possible transparency was assured. It is a very significant omission that Plimer makes absolutely no reference to this broader review. It is also a considerable contrast with his own book, where his views remain ‘his views’ and have not been considered for their veracity by anyone else.
Plimer’s book, while appearing very scientific, adopts an unbalanced approach to the topic. In a similar way to his treatment of sea level, Plimer claims that the IPCC says more than it does about what will happen to storms. He implies that an ‘unquestioning mantra’ has been accepted (p407-8), but most of what he says in his text is also said, with appropriate cautions regarding the uncertainty, in the IPCC AR4. Plimer makes much of the fact that the warmest year over the past few decades was 1998, with the claim that it has cooled since then. We are informed that having several decades of data is an insufficient base on which to build models, so it is hard to understand why observations over one decade are enough to establish the current temperature trend, particularly given the large number of perturbations such as solar and volcanic which this book draws attention to. Indeed on page 310 we are informed that ‘it seems that sea level has a large variability and is poorly understood, hence observations over a short period must be interpreted with great caution’. Exactly; so this level of caution should also be adopted when treating a short period of temperature record, and the longer term trend is a warming trend.
Scepticism and scientific debate are essential elements of science and the scientific process. In that context, I would regard it as completely appropriate if Plimer’s arguments sparked a major scientific reconsideration of one or more issues in climate science, but this book has not been written as a contribution to any scientific debate, and is evidently not aimed at a scientific audience.”
Professor Matthew England is an ARC Federation Fellow, and Joint Director of the University of New South Wales Climate Change Research Centre.
“In 2008 I debated Ian Plimer on one of Sydney’s top rating radio stations about the facts and fiction surrounding climate change. All of what he had to say was either patently untrue or horribly misleading. Foremost among the misleading is his assertion that in the deep past the Earth experienced much higher air temperatures and much higher CO2 than we have today. Yes, this did occur at various times, for example 40 million years ago during the Eocene. But does Plimer tell his readers that at this time sea levels were 50 metres higher than today?? Certainly humanity did not yet exist and importantly all of our cities, agriculture and infrastructure were millions of years from being built. In fact, the building of our cities, infrastructure, and the location of modern farming have all been set during a very stable climate era – the Holocene.
Ian Plimer’s affectionate recollections of past warm and fertile times are dangerous. We can go on and warm the planet to levels of those past eras, but there will be profound payback, via sea level rise, ocean acidification, and climate change that is of an unprecedented scale since civilisation began.”
Dr Graeme Pearman is Honorary Senior Research Fellow at Monash University in Melbourne and Director of Graeme Pearman Consulting Pty Ltd.
“It is difficult to comment usefully on a book as voluminous as this, especially in a few sentences. On the one hand, Ian Plimer has presented a comprehensive coverage of his understanding of how the Earth’s climate has varied through time, geological and historical. It is a shame that this work, particularly Chapter 2, was not submitted for peer review and scientific journal publication as it may have contributed to the already existing literature on this field of study.
On the other hand, if Ian or those who read this book are under the misapprehension that mainstream climate scientists are unaware of the fact that the Earth’s climate has always been changing and will continue to do so into the future, then they are simply wrong. On the contrary, over the past several decades climate science has focused exactly on this: how do we rigorously separate out climate change and variability that is caused by the many potential and natural factors from those that are human induced? How do we anticipate change into the future that may be human-induced and unprecedented? It is this work that, with a high degree of confidence, underpins the conclusions that much of the current warming is most likely due to increased greenhouse gases and most unlikely due to other natural factors.
The most disappointing aspect of this book is the wide use of subjective and often emotive text, unbecoming of a scientific treatise, and this is despite a tirade in Chapter 1 suggesting that Ian is the only scientist, or geology the only field of science that understands the scientific method, is rigorous in the use of observations, and the setting and testing of hypotheses. To suggest that the discipline of geology is the framework in which to analyse the climate-change issue, is as indefensible as suggesting that climate models alone are the basis for determining human response to this issue. Integration of knowledge across these fields is essential but broader than this. For example, where are the chapters on the observational records of biological and social responses to climate change, the adaptive capacity of these systems and how they feedback on the kinds of change that have occurred and will occur into the future? Where is the human component to this issue, the causes, the impacts and the risk management?
Perhaps an even more disappointing aspect of the book is the use of misleading argument in which literature appears to be selected to support a position, rather than to expose the uncertainties. I find this particularly disturbing with the Figures, where it is often unclear as to the source of the information, the averaging periods in time and geographically, and the errors in the data presented. For example, the use of regionally-specific observations of a past change to assert global change, is as unacceptable as the meteorologist using the data from one thermometer, about which the calibration and representativeness is uncertain, to establish global conditions.
Ian seems to have been surprised that the formulation of the summary reports of the IPCC is not science. Of course not: the IPCC was established to avoid narrow, disciplinary and personal views of what collectively the current scientific publications can tell us. It is based on published science, but mostly it is a tool to bridge the gap between the current knowledge and its uncertainties and the policy developers, private and public, who have to deal with the reality that we never know as much about an issue as we would like, but we still have to make decisions. This book fails to really address the issue of how we manage the risk that Ian may be wrong in his assertions. In this regard the final section of the book is weak. And in any case, how do we manage the reality that observations of the past, on which Ian is rightly focussed, may not provide wisdom about what might happen in a world where human activities have changed the environment to an extent and at a rate where this knowledge is of little guidance?
This publication clearly represents an extraordinary personal effort on the part of Ian Plimer, and undoubtedly he has much to offer the climate-science community, as other geologists have done. It would be better that he joins that community rather than presupposes that the rest are somehow misled, inferior scientists or perhaps just stupid. But I have concerns that this mode of publication, the approach and the narrowness of the disciplinary coverage, and the impact this book may have on the uninformed reader, may have limited the contribution that the effort deserves.”
Professor Nathan Bindoff is a physical oceanographer and Director of the Tasmanian Partnership for Advanced Computing (TPAC). Partners include the University of Tasmania, CSIRO Marine & Atmospheric Research and the Antarctic Climate and Ecosystems CRC. He was a Coordinating Lead Author of the IPCC AR4 Working Group 1 chapter on oceanic climate change and sea level observations (Chapter 5).
“I have read the various articles in the SMH (Sheehan) and can see that this book repeats many of the common mistakes that are frequently made by climate scientists who haven’t read the peer reviewed literature or the peer reviewed science reports undertaken by the Inter-Governmental Panel on Climate Change (IPCC). While the earth has shown large variations in its climate, the current period of change since the start of the industrial revolution is unique in the history of the Earth. This period can be demonstrated, using the scientific method, to result from the changing composition of the atmosphere caused by man’s activities. I am sceptical that the ‘missing science’ reported in this book has been submitted for review as in the normal scientific process.”
Professor Barry Brook holds the Foundation Sir Hubert Wilkins Chair of Climate Change and is Director of the Research Institute for Climate Change and Sustainability at the University of Adelaide.
“Ian Plimer’s book is a case study in how not to be objective. Decide on your position from the outset, and then seek out all the facts that apparently support your case, and discard or ignore all of those that contravene it. He quotes a couple of thousand peer-reviewed scientific papers when mounting specific arguments. What Ian doesn’t say is that the vast majority of these authors have considered the totality of evidence on the topic of human-induced global warming and conclude that it is real and a problem. Some researchers have shown that the Earth has been hotter before, and that more CO2 has been present in the atmosphere in past ages. Yes, quite — this is an entirely uncontroversial viewpoint. What is relevant now is the rate of climate change, the specific causes, and its impact on a modern civilisation that is dependent, for agricultural and societal security, on a relatively stable climate. Ian pushes mainstream science out of context, again and again.
Ian also claims that a huge body of scientific evidence — indeed, whole disciplines such as geology and astronomy — have been ignored. This is an extraordinary proposition and quite at odds with the published literature, as reviewed by the Intergovernmental Panel on Climate Change. I wonder if Ian has ever read their reports to find out what they actually do say. Terms like ‘solar’ and ‘volcano’ get frequent mentions, and there is a whole chapter on ‘paleoclimate’. Ian’s stated view of climate science is that a vast number of extremely well respected scientists and a whole range of specialist disciplines have fallen prey to delusional self interest and become nothing more than unthinking ideologues. Plausible to conspiracy theorists, perhaps, but hardly a sane world view — and insulting to all those genuinely committed to real science.”
Dr Harvey Marchant is a marine biologist and Visiting Fellow at the Australian National University and Lead Author on three of the four principal IPCC assessments.
“One comment that was reported in the Weekend Australian was Ian Plimer’s criticism of the IPCC as being dominated by atmospheric scientists and a lack of scientists from other disciplines. As an IPCC Lead Author for the 1995, 2001 and 2007 Assessments and a marine biologist I was a little put off. Sure there are plenty of atmospheric scientists, as you would expect, but the authorship is levened with a substantial number of scientists from other disciplines – geologists, marine biologists, terrestrial ecologists etc. In previous publications Plimer has expressed the viewpoint that the present warming is principally due to ‘natural’ forcings rather than anthropogenic CO2. The evidence included in the 2007 IPCC Report explicitly refutes this.”
Ian Lowe is Emeritus professor of science, technology and society at Griffith University,Qld and President of the Australian Conservation Foundation.
“I have also twice debated climate change in public with Ian Plimer. His position is a combination of sound geological knowledge which is irrelevant to the debate about climate change, and a wilful misunderstanding of recent climate science.
His book will be applauded by those who are desperate to find some pseudo-scientific justification for their unthinking rejection of the reality of climate change, but it is not a serious contribution to the debate. The harsh reality is that the probability of dangerous human interference to the Earth’s climate system is now alarmingly high and the survival of civilisation demands urgent concerted action.”