Will thirst for power be death of us all?

Few subjects are changing as rapidly as energy, in terms of its applied science and its social and economic aspects. The ambitious idea of producing an all-encompassing encyclopaedia is therefore timely. The risks in such a venture are considerable, especially as the energy field attracts dedicated advocates and the more than occasional eccentric. By and large, Cutler Cleveland has done a good job in masterminding this huge encyclopaedia, although the size and price will limit its market to a few libraries, and there are no links to an internet resource for the student or teacher.

The encyclopaedia's coverage is broad. The physics, chemistry and engineering of individual energy sources are well covered, and it is arguable that the encyclopaedia adds little to what the average undergraduate would come across in standard textbooks. But it is difficult for students to find concise essays on issues such as the history of energy sources and their uses, the environmental impacts of alternative fuels and the links between the economy and energy. Cutler makes a determined effort to embrace these topics, and in so doing he provides students with a valuable source of information, if they can secure access to it. Modern engineers, for example, remain largely ignorant of the economics of energy, just as economists are rarely exposed to the science. In these volumes, some 350 authors contribute to about 400 entries, with the authorship biased towards North American scholars. In addition to the entries, there are a comprehensive glossary of terms, a chronology of energy-related events, a list of energy organisations and tables of conversions and equivalences.

Given the scale of the enterprise, detailed review has to focus on entries selected at random. The essay by Thomas Sundqvist, Patrik Soderholm and Andrew Stirling on valuing environmental impacts of electricity generation starts well and gives examples of how economists have placed monetary values on the damages done. Unfortunately, it closes with some basic confusions on the money value one might attach to global warming, arguing that individuals' preferences are not well formed enough to secure "valid" answers. This hardly seems true given that most people have reasonably well-informed views on climate control - few could argue they have been starved of information or exposure to the issue.

The authors similarly raise a much-discussed issue about valuing lives in different countries. Monetary valuation rests on the notion of what individuals are willing to pay to reduce a risk, in this case the risk to life. Since willingness to pay is constrained by income, risks will be valued less in a poor than in a rich country. In the hypothetical case of all global-warming damage occurring in poor countries, less action would be justified than if that impact were spread across poor and rich countries.

On the face of it, this seems unfair. But a moment's reflection shows that this disparity is commonplace. No country spends more of its income saving lives abroad than it does at home. The UK spends 8 per cent of its gross national product on the National Health Service and just 0.3 per cent on overseas aid. What seems like unfairness in global-warming valuation is revealed to be an instance of a much wider disparity in the way "home" and "overseas" lives are valued. It may still be unfair, but those using the unfairness to criticise the monetary valuation of global-warming impacts need to explain why their discomfort does not extend to the other, far more dramatic, disparities.

Adam Rose and Snorre Kverndokk tackle the thorny issue of equity and fairness in their all-too-brief essay. They achieve a remarkable amount in a few pages, introducing the reader to different theories of social justice and showing how hard it is to choose between them. One suspects some readers' eyes will glaze over at the presentation of "utility possibility frontiers", but the social scientist may have similar problems with some of the more technical engineering entries.

The essay by William Moomaw addresses climate change and energy policy. He pinpoints an issue that is often overlooked by the advocates of new low-carbon energy sources: the need to factor in the conversion of the existing infrastructure. Economists teach that past costs are sunk costs - they cannot, or should not, influence current decisions. But fuels such as hydrogen cannot displace current motive fuels without our facing up to the massive cost of converting the fuel distribution network.

An example of the truly unusual in this encyclopaedia is Vaclav Smil's fascinating short entry on people and animals. Animals as sources of power are still common in poor countries, but Smil provides an interesting historical perspective on their role in rich countries. As an illustration, at the end of the First World War, the US had 21 million farm animals, and one fifth of all farmland was devoted to growing feed for them.

If issues such as climate change are to be addressed, something dramatic has to happen to the way we use fuel for transport, on land and in the air.

David Greene provides an overview of alternative transport fuels. Like Smil, he also has interesting facts at his fingertips. In the rich world, we travel for about an hour per day. Non-car owners spend about 3 per cent of their incomes on travel, car owners spend dramatically more, about 10 to 15 per cent. In the poor world, average motorised travel is a matter of a few minutes per day, but that is changing fast. Facts of this kind serve a purpose: imagine the entire world has fuel-use patterns similar to those of the current rich world. Apart from the environmental implications, the demand for liquid fuels would be unsustainable. The prospect has to be for some dramatic change in the way we travel or some form of social collapse.

Indeed, "sociopolitical collapse" is Joseph Tainter's contribution to the encyclopaedia and, in my view, by far the most intriguing and exciting entry. We know that seemingly massively successful societies collapse - the Maya and the Mycenaeans, for example. Could energy problems be the source of the next large-scale social failure? Climate change seems to have been involved in some past collapses, as has natural resource scarcity in the form of wood becoming unavailable because of deforestation. Tainter pursues some examples of the Guatemalan Maya, the western Roman Empire and Mesopotamia. He argues that there are potential lessons from all these episodes, and he makes a plea for more and better understanding of long-term historical trends. I, for one, immediately sought out his 1988 book, The Collapse of Complex Societies , which I had been unaware of.

Some idea of the scope of the encyclopaedia is given by several of the essays that appear at first glance unrelated to energy. Linda Gaines provides a survey of paper recycling. The connection to energy becomes quickly evident: paper production is energy-intensive. Does recycling reduce overall energy demand per unit of paper output? Generally, the answer is yes and, hence, saved energy should be an element in any economic appraisal of recycling. Gaines focuses solely on the energy calculus, so her essay does not cover every issue that would need to be taken into account when deciding on recycling programmes. But the narrow focus is justified given the goals of the encyclopaedia, and anyone wanting a quick but authoritative summary of the technology of paper production will find it here.

Finally in this random selection process, Mathis Wackernagel and Chad Monfreda offer an overview of the popular "ecological footprint" notion. In essence, the idea is that one should add up the area of land needed to sustain a given level of economic activity in, say, a city or in a production process.

The procedure for computing the ecological footprint is as follows: identify and measure the components of consumption in a given region - this includes food, energy, transport, consumer goods and services; for each item of consumption, estimate the area of land that would have to exist to generate the resources involved in that consumption; add the land areas to determine the complete footprint of the region; and compare the footprint with the size of the region generating the footprint. The idea is to compare what the activity in question requires by way of land. This is then compared with the supply of land. If "demand" exceeds "supply", there is an ecological problem: the activity in question is unsustainable. One obvious application is to see if a nation can sustain its own activities from its own resources, a widely applied use of ecological footprinting.

Although Wackernagel and Monfreda do a good job of explaining the footprint concept, neither they nor the encyclopaedia in general subjects it to any criticism. The result is a biased account of a dubious construct. Pursuing the idea of self-sufficiency in resources, for example, one can ask why nations should be self-sufficient. Trade explains why self-sufficiency is an outmoded concept. Moreover, why stop at nations? Perhaps local communities should be self-sufficient, or even households or individuals.

It is easy to understand why the encyclopaedia could not have essays for and against some of the arguments in some of the entries, but it not so easy to understand why some essays should be so unbalanced.

Overall, this is a brave and largely worthwhile venture. Perhaps its chief attraction is the scope and hence the potential for learning and surprise.

Let us hope the publishers find some way to produce an electronic version with cheaper access for the average student.

David Pearce is professor of environmental economics, University College London.