The age of sustainable development

only to its more obvious demands for water in cooling and electricity generation, but also its many uses in fuel extraction and purification – and their accompanying pollution hazards. There are no easy answers. After that the two basic topics combine – Energy for Water – with pumping and purification needs prominent – followed by Constraints, notably the extent to which natural heat and cold may impede water quality, even availability, for particularly purposes; and Trends – the impacts of population increase and climatic change. In his eighth chapter Webber turns to Technical Solutions. One should perhaps read it more in hope than expectation, not least because cost now also enters seriously into the debate. Webber’s basic premise is that less water = more energy, and vice versa, so that any solution is likely to depend on whether a particular country has more or less of either. But even with ample energy, solutions such as desalination are only won at substantial cost. Anaerobic digesters of waste materials containing organic substances feature as sources of improved water quality, methane and fertiliser. But they are usually only realistic where large volumes of waste must be handled. And while some sewage treatment plants (e.g. in London) have long fruitfully also burned the resulting methane to generate their energy needs, many apparently still vent it – a serious greenhouse gas – to atmosphere. The final chapter turns to Non-Technical Solutions – in fact more a wish-list of research and development projects, as the author sees it, than a catalogue of actual answers. Much of it focuses on the potential for water and energy economies presented by natural temporal, seasonal and climatic fluctuations in demand. But advantage of these can usually only be secured from consumers by differential metering and pricing. And that takes us straight back into the preceding province of technical solutions and their problems. Webber gives one cautionary example from his own home base in Austin, Texas. The city spent $50 million on installing smart meters. It then discovered that it would have to spend another $50 million putting in place technology capable of handling their data. This book makes for an interesting read. But one wishes it was likely to be critically read by all who imagine we do not face intractable energy and water supply problems, or that there are any miracle answers.