Dr. Greg Ayers on Climate Science, Pell and Plimer for the Hansard record

Dr Ayers—Thirdly, I think at some stage it would be appropriate for me to respond to the letter from Cardinal Pell, which was incorporated in Hansard in the last estimates committee meeting when we were not present……..
Dr Ayers—The issue from my point of view and why I sought leave to respond is that the cardinal has, in terms of the letter we incorporated in Hansard, made a number of propositions about aspects of climate science that I have feel should not remain unanswered on the public record in this place. I would have been happy to have responded directly to the cardinal but he has not approached me and I am not aware that he has spoken with any others in the climate science community. I thought it was important to respond.
The difficulty with the assertions made in the cardinal’s letter is that they are based not upon contention in the climate science field but on a book written by Professor Plimer entitled Heaven and Earth—Global Warming: The Missing Science. The contents of the book are simply not scientific. I am concerned that the cardinal has been misled by the contents of this book and I do not think it should stand on the public record for that reason.
Why would I say this book is not science? It is not me who says it so much, although I have read it myself; it has been widely reviewed by people in the scientific arena and it has been very heavily criticised for not presenting science but presenting a polemic from one individual. It has not been scientifically peer reviewed. I would like to step you through each of the assertions in Cardinal Pell’s letter. The cardinal I do not anticipate would be an expert in these fields of science, so he has quoted very heavily from this book and the book is, frankly, misleading to all Australians in terms of what it represents. I will read you once scientific review to give you a sense of what one scientist from the University of New South Wales said about the book. He said: Plimer has done an enormous disservice to science, and the dedicated scientists who are trying to understand climate and the influence of humans, by publishing this book. It is not “merely” atmospheric scientists that would have to be wrong for Plimer to be right. It would require a rewriting of biology, geology, physics, oceanography, astronomy and statistics.
Plimer’s book deserves to languish on the shelves along with similar pseudo-science such as the writings of Immanuel Velikovsky and Erich von Daniken.
That is from Professor Michael Ashley from the University of New South Wales. That is very strong, I am sure you will agree. I have read the book myself and it contains phrases that had nothing to do with science. There is a somewhat gratuitous attack on Chancellor Angela Merkel on page 441, the same page essentially that contains a gratuitous attack on Minister Wong. Page 470—…..
Dr Ayers—No, the point is, Senator, that it is not science. The book says that it is Global Warming: The Missing Science. Were it science, that would be fine. To quote Professor Ashley again:
The book is largely a collection of contrarian ideas and conspiracy theories that are rife in the blogosphere. The writing is rambling and repetitive; the arguments flawed and illogical. …
Dr Ayers—Chair, my proposition here is that there are about half a dozen assertions in the letter and I would like to respond to each one, if I may. First of all, I should just say that a critique of Professor Plimer’s book is available. There is another university professor, named Ian Enting, at the University of Melbourne and if you put ‘Enting’ and ‘Plimer’ into a search engine you will come up with a 55-page document detailing mistakes, misunderstandings and misrepresentations. That is available and I will be sending that to the cardinal. Everybody who wants to dig into an analysis of the book can do that.
On the first thing, the Roman warming, Professor Plimer asserts that the temperatures during that period were two degrees to six degrees warmer than today. If you go through the book, there is not a single scientific reference in the book that makes that statement. It is an assertion without any scientific evidence. The example of a book by Lamb, published in 2007, is about as close as you get. The strongest statement in that says:
By late Roman times, particularly the fourth century AD, it may well have been warmer than now —
Now being the mid-1970s when the book was written. In fact, we know the earth was a little warmer. So there is no cogent evidence being provided at all for that statement. I have no idea—…..
Dr Ayers—I have no idea where the two degrees to six degrees comes from. I will heed the chair’s advice.
What is interesting about that is that there were things like assertions that grapes were grown in England and that the two degrees to six degrees would support that. Grapes are grown in England today. There are more than 400 vineyards. That sort of level evidence is not science; it is anecdote. If Professor Plimer has time he should publish it in a scientific journal and then we can have it level. That is that: there just is not any evidence in the book.
If we move on to the medieval warm period, he references a study of 6,000 bore holes. These are holes in rock where the temperature diffuses down and with a mathematical technique called inversion you can reconstruct what the past temperatures would have been based on thermal diffusion. The reference appears to come from an article by Professor Wally Broecker, a renowned oceanographer, written in 2001. Professor Plimer does not quote Professor Broecker’s conclusion, which is:
The case for a global medieval warming period admittedly remains inconclusive.
So that does not support it. What Professor Plimer then does is take one of the references from this book and refers to a 1997 paper by an author list led by someone named Wang. What is interesting about that is that the same authors in 2008 published a subsequent paper which says, in fact, that you cannot use their first paper for
the purpose. They say:
The results of our earlier paper cannot be used for comparing the medieval warm period to warmth in the 20th century.
Which is exactly what Professor Plimer does. This paper was available in 2008, a year before he published his book. He has used a paper that the authors themselves say cannot be used in a particular way. That is not science.
A second thing to do with the medieval warm period is on page 66, where he says:
Bore holes give accurate temperature histories for a thousand years into the past ... Northern Hemisphere bore hole data shows the medieval warm period and the cooling of 2 degrees from the end of the Little Ice Age.
When you go and look at the scientific paper—which you assume is about bore holes, Northern Hemisphere, medieval warm period—you discover the paper is actually not about bore holes but about an ice core; it is not taken in the Northern Hemisphere, it is from the Antarctic; and it is for the period 10,000 years to 20,000 years ago, not the Roman warm period. That level of getting references wrong is not science. So the book does not provide evidence about the medieval warm period or the Roman warm period.
The cardinal in his letter says that he has metadata analysis—that is, an analysis that sits above all the papers that are random reviews—but he just cannot find it. That’s okay. If he can find it I would be happy to look at it. I know of three metadata analyses, though. One of them is in the Intergovernmental Panel on Climate Change Working Group I report from the Fourth Assessment Report. It answers all these questions.
However, there are those who feel that the IPCC is somehow biased, so they would not use it.
At the time it was being written in 2006, the US National Academy of Science carried out an independent review and wrote a report entitled, Surface temperature reconstructions for the last 2,000 years, because there were those who said the IPCC process was not robust. So we have an independent report from the National
Academy of Science. Their conclusion is:
• It can be said with a high level of confidence that global mean surface temperature was higher during the last few
decades of the 20th century than during any comparable period during the preceding four centuries.
They go on to say:
• Less confidence can be placed in large-scale surface temperature reconstructions for the period from A.D. 900 to 1600.
The medieval warm period is in there.
Presently available proxy evidence indicates that temperatures at many, but not all, individual locations were higher during the past 25 years than during any period of comparable length since A.D. 900.
The Roman warm period was 250 BC to 450 AD. So they do not support it. That is two metadata analyses.They were both available to Professor Plimer. They are not mentioned in the book. So it is not a fair review of the scientific literature.
The final point I will make is that the US EPA, in December 2009, published the administrator’s results on the ‘endangerment’ and ‘cause or contribute’ findings for greenhouse gases under section 202(a) of the Clean Air Act. This was a process in which the Administrator of the EPA made a finding that the current and projected concentrations of six well-mixed greenhouse gases in the atmosphere threatened the public health and welfare of current and future generations. I will not go into the ‘cause or contribute’ finding, but the point was that there was a profoundly careful review. They had a 60-day consultation period for public comment, and 380,000 public comments were taken in. They all included the statements made in Professor Plimer’s book that have unfortunately misled Cardinal Pell. Not one of them was supported.
So there are three metadata reviews—from the IPCC, from the National Academy of Sciences and from the US EPA—that do not support the propositions that are being put.
I will move on to carbon dioxide, where Professor Plimer has brought to the attention of anybody who reads the book—and Cardinal Pell has picked it up—that 90,000 measurements of CO2 were done over the last 150 years by a particular method. He contrasted those with the carbon dioxide record from Mauna Loa in Hawaii, which from the fifties has documented the increase in human activities. It looks as though that is a fair comparison, but it is not. It is actually verging on disingenuous. The fact is there are 150 stations measuring CO2 worldwide, 110 of which meet the standards such that the annual analysis done by the World Meteorological Organisation’s World Data Centre for Greenhouse Gases uses those to describe CO2 everywhere. You simply cannot, if you pay attention to all the data available, reach the conclusion that CO2 levels were higher in any other period in time.
Professor Plimer does not mention that in 1986 all the old data that were collected over the last 150 years were reviewed in a paper by Fraser et al. I can give you the citation if you like. The issue here is that, in Australia, we have, at Cape Grim in Tasmania, one of those 110 high-quality baseline stations measuring CO2.
If you look at that and if you look at the work done in the Antarctic Division on ice cores and firn, which is the loose layers of snow that compact down at about 80 metres—air has been extracted all the way down from the present down into the past, through the firn layer and into the ice cores, back 2,000 years—there is absolutely no possibility that the global CO2 levels were 400 parts per million last century. It is just implausible. Yet, on the basis of 90,000 measurements from a paper by a fellow named Beck, that is the conclusion put in the book and that is the conclusion picked up by Cardinal Pell.
Professor Plimer also did not cite the fact that, during the year after the Beck paper came out, there were two rebuttals published in the same journal pointing out the errors in it. They were not referred to. So there is  very selective use of data the whole way along. The Australian scientists who have worked on the carbon cycle include those working in Canberra at one of the two international offices of the Global Carbon Project, where on an annual basis CO2 levels are reviewed, the carbon cycle is reviewed and the budget of carbon going into the atmosphere, the oceans and the land surface is all reviewed and published. It is not in this book because, if it were in the book, the conclusions that are in the book could not be reached.
So what I am going to suggest to Cardinal Pell in due course is that he comes with me and visits a range of climate change science establishments in Australia and has a look at the science directly, not through this book but through the lens of what men and women in Australia are doing in scientific institutions that is valid, that is published and that has real credibility. My contention is that Cardinal Pell may well become an ambassador for the quality of climate change science if he is exposed to the quality of the science that is done. That is my aspiration. He can make his own decision about whether the science says what Professor Plimer says, but I think he will become an ambassador for the quality of the science we do in this country. It is absolutely not honoured by this book.
I know these are strong statements but I am the head of a national agency and the information that is out there is not adequate based on what I know. So I am taking my job seriously and making a strong statement.
There are some other things in Cardinal Pell’s letter that I will not go into because I can see people’s eyes will start to glaze over. I will just make two other comments. At one stage he lists greenhouse gases. Included in the list is the gas nitrogen. That is not a greenhouse gas; it is 78 per cent of the atmosphere. You cannot have people out there telling the public that nitrogen is a greenhouse gas, because it is not.
The final point I will make is on the statement from Professor Plimer that CO2 from fossil fuels accounts for 0.1 per cent of the greenhouse effect. There is a parameter called climate sensitivity. It is the temperature increase you would get if you doubled CO2. The conventional view, which is very well attested to in scientific literature, is that it is about two or three degrees. That is roughly it. At equilibrium, when everything comes into balance, that is what the temperature of the Earth would go up by. Professor Plimer says that is not right;
he says it is only half a degree. At least, he says that in one part of his book. In another part he says that it is 1½ degrees. So he is not consistent with himself. You can do a very simple calculation. Professor Enting—the guy who has done the 55 pages collecting problems with Professor Plimer’s book—shows you how to do the calculation. You can compute the change from 280 parts per million pre the industrial age to 385 now. Using Professor Plimer’s climate sensitivity, it would increase temperature by 0.23 degrees. We have seen about 0.7, but he has put his sensitivity below that. If 0.23 degrees is only 1.1 per cent or one thousandth of the greenhouse effect, it implies that the greenhouse effect is 223 degrees and without it our planet would be as cold as the outer planets. So the calculations in this book are just erroneous. I will give up at this stage. There is plenty more I could go on with, but I will not.