The UnAustralian

Tuesday, July 08, 2003
You Are The Weakest Link

As I mentioned below, it was a column by Alan Wood which inspired me to blog about the IPCC/Castles/Henderson.

The column is high on rhetoric and low on about everything else.

Essentially, it's one big argument from authority, with Wood uncritically accepting what Castles and Henderson have written, and stating that the authors have "so far have only succeeded in further exposing their inadequate grasp of economic history and statistics".

His source for this is a rebuttal article in the July issue of Energy & Environment (which happens to be literally one of the most obscure and irrelevant scientific journals around - which is a good indication of the quality of Castles and Henderson's work). Unfortunately, this article or it's abstract isn't available on the journals website. As far as I know, Castles hasn't pre-published it on the internet like he did with his first critique. As for clues on it's contents from Wood's article; "[i]t is impossible to repeat the detailed debate here".

Wood does have some statements about the critique, but they appear to be from the first Castle/Henderson document. I'm going to give Wood the benefit of the doubt and assume that he hasn't actually read the IPCC reply, because otherwise he is either illiterate or a liar.

One example. Wood writes:

[A] central issue is the IPCC's use of market exchange rates when measuring and projecting gross domestic product across countries. Castles says this gives a badly distorted picture, and a measure known as purchasing power parity, which removes price distortions from the comparisons, should be used.

The IPCC used both market exchange rates and purchasing power parities.*

Alan Wood didn't even have to read the whole IPCC reply to work this one out. On the abstract, it clearly states "IPCC scenarios did include PPP-based scenarios, which Mr. Castles and Mr. Henderson have conveniently ignored".

The other point which Wood makes is that "[t]his and other mistakes, including the assumption of what Castles calls "fantastic" – that is, unbelievable – relative rates of future growth in the developing countries, leads to overestimates, possibly substantial, of carbon emissions and hence global warming".

As I've already pointed out, this argument is highly flawed as the high rates of growth are seen in high growth scenarios (that is, scenarios designed to simulate very high rates of growth), and that high rates of growth do not necessary lead to higher CO2 emissions (in fact, the opposite is more likely).

However, lets look at these "fantastic" growth rates. The Asia region in the economic scenarios shows the greatest growth rates. In the B1, B2, and A1-MESSAGE scenarios (ie. high to moderate third world growth rates), the Asia region grows at between 2.7 and 3.4% per year between 1990 and 2100 (growth rates in PPP). Historically the USA, Canada and Japan have grown at a rate of between 3.4 and 3.8% between the years 1870 and 1985.

So what does Wood have? An argument to authority, and two debunked assertions. Not much. However, his argument to authority is interesting. Generally, when one makes an argument to authority, one should have some authority. Rather Wood takes the word of two individuals with a reputation for dishonesty and no experience of emission modeling; and puts it above the IPCC, World Bank, the US Department of Energy and other such organisations.

* Ironically the IPCC is one of the few organisations which uses both market exchange rates and PPP, among professional researchers, market exchange rates are vastly preferred. Doubly ironically, despite recommending that future modeling be done under the auspices of the OECD, Wood, Castles and Henderson appear to be unaware that the model developed by the OECD (the GREEN model) uses market exchange rates not PPP.
| 10:31 PM