Five years ago I began to collect information about the environment for a book I was then writing, to be called Legacy and Challenge. I had written some of it, and its focus was on the next fifty years; it was a sequel to What Was It All For? The Reshaping of Australia, published by Allen & Unwin in 2005. Global warming and its threat to the environment, not just that of Australia, but everywhere, was something I had not paid much attention to, but clearly it would have to be an important part of this chapter.
But the more I read, the more puzzled I became. The science on which ‘global warming’ was based seemed somewhat slight. The physics of radiative transfer was plain enough: carbon dioxide has the capacity to retain heat in the atmosphere, and the more there is, the more heat is retained. Carbon dioxide levels were going up, there seemed no doubt about that, so that heat would be going up too. And the data seemed to show that it was, in an irregular fashion. But why the great scare, I wondered. The relationship between increases in carbon dioxide and increases in retained heat was not linear but logarithmic, so a doubling of carbon dioxide from pre-industrial levels would take quite some time, and a good deal of the added heat had already arrived. And what was wrong with a bit more heat, anyway? Considerable parts of the planet would greatly welcome it.
Ah, the reason was that the models predicted that more heat would lead to more drought and generally to a worse climate for everyone. The models were General Circulation Models of the earth’s climate — each a gigantic set of simultaneous equations that modelled all the processes involved in climate; there were a lot of them. I’d once made a model of a large set of federal elections using simultaneous equations to see if I could work out the various effects of local, regional, state and national forces that produced a ‘result’, so the idea was familiar enough. There were thousands and thousands of those equations, and I could not have done it without the large computer that the ANU had recently acquired.
But in the electoral example I knew all the forces that were at work that could be measured. There might have been other ones. For example, the Almighty might have intervened to achieve a particular outcome, working in mysterious ways his wonders to perform; I wouldn’t have been able to pick that up. But given what we knew about elections, and using all the subdivisions of counted votes that there were, I could be pretty confident that I’d captured all the important variables, given that I was actually interested in the power of those particular variables to determine results. How important were local forces in a national election, for example, and where were they important, and why were they important there?
So I became, fairly quickly, an agnostic about global warming. Yes, I knew that the Intergovernmental Panel on Climate Change (IPCC) believed in it, and that the Academy of Science, or its executive, anyway, had said it was true, and that the government thought so too. But I’d spent thirty years in assessing just such propositions when put forward by academics who wanted money for research, not only on Australia, but in Canada, too. I had looked at hundreds of proposals, and across all fields. I knew how to go about asking the right questions. And I wasn’t much impressed by the answers I thought I was getting.
Our climate is altogether vaster than a set of elections, and it is fair to say that we know much less about what determines climate than we do about what determines election results, or economic downturns, for that matter (another area where large models are employed). My intellectual interests began to accommodate ‘global warming’ at the expense of my book, which remains much where it was in 2007. So over the next little while I will put together what I have found out about global warming, or (since it hasn’t been warming in the nice linear way it was doing in the 1980s and 1990s) what we now call ‘climate change’. I am still an agnostic about global warming, and completely sceptical that our present carbon tax will have any effect in lowering greenhouse gas emissions, or do anything more inside Australia than redistribute people’s money, while making everything more expensive for everyone.
In looking at global warming in 2012 I will follow what I take to be the central propositions of the IPCC, which is the body that issues assessments of what we know about climate every few years; the next is due in 2014. The IPCC, incidentally, is a political body, not a scientific one, but scientists prepare the material that comes out in its Reports.
What are these propositions? First, the earth is warming. Second, the warming is unprecedented. Third, the warming is the result of human activity (or significantly so). Fourth, if we don’t stop this warming there will be seriously unpleasant results for humanity. Fifth, the best way to stop it is to control greenhouse gas emissions, since carbon dioxide is a so-called ‘greenhouse gas’. And sixth, this needs to be done at a global level (hence all the conferences where thousands of people create lots more greenhouse gas emissions by flying to distant and agreeable places).
I wrote a paper about global warming in 2008, and delivered it as an address to the Australian Planning Institute. You can read it by going to Writings at the top of the home page, and finding ‘A Cool Look at Global Warming’. What I will be doing in the essays that are to come is to see where we have got to in the last five years.
But as a parting line, Australians would be unlikely, I think, to regard temperature as the important variable in their climate. We would be looking, often desperately, at rainfall, which has great capacity to affect us all. Is it temperature that determines our rainfall? I don’t think so. In this matter eastern Australia is much affected by the El Nino Southern Oscillation (ENSO), which gives us dry years in el Nino periods and wet ones in la Nina periods. We’ve had nearly three years of la Nina. Does temperature determine ENSO. No — at least, almost certainly no. Here as elsewhere in the domain of climate, we don’t what the causes are.
So in the next essay I’ll put down what I think is important about temperature, and how we measure it, and what that tells us. It won’t be for a few days.
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[…] since, and you can read that here. Even earlier, I tried to do what I am now doing, and started it here, and followed it with a piece on measuring global temperature, and you read that one here. Then I […]