Using Water to Understand Human Society

Water, according to Tvedt, is a unique natural resource for two reasons. First, it is absolutely essential for all societies, because we cannot live without it. Secondly, it is always the same. Whatever you do with water on the surface of the Earth, it reemerges. "You can destroy or create rivers and lakes," he says, "but you cannot destroy water itself."

Tvedt used the example of the industrial revolution to show how water can help to understand human history. Historians have proposed two contrasting theories to explain why the industrial revolution started in Europe, specifically in Britain, and not in China, India or Australia. The early industrial revolution was enabled by the power of water mills, and bulk transport of goods by canal. Britain's rivers were perfect for both things. They provided a good network across the country. All are fairly close to the sea, with good flows throughout the year and not too much silt. Elsewhere in the world, rivers were too silty, too large and uncontrollable, all flowing in the same direction or had flows that were too seasonally variable.

Global water trade

Another speaker at the conference demonstrated how social scientists are now thinking analytically about natural resources. Maite M. Aldaya, from the University of Twente (The Netherlands), presented the water footprint concept. The water footprint of a product (commodity, good or service) is the volume of freshwater used to produce the product, measured at the place where the product is actually produced. The water footprint for an individual, community or business is the total volume of freshwater used to produce the goods and services consumed by that individual or community or produced by that business. Water use is measured in terms of water volume consumed (evaporated) and/or polluted per unit of time.

Developed by Arjen Hoekstra, based on Tony Allan's idea of virtual water, water footprints allow us to visualise the transfer of water that occurs during global trade. The global trade in virtual water is about 1,600 billion cubic metres a year, equivalent to 16% of world water use. Australia, the driest inhabited continent on Earth, is one of the world's largest exporters of virtual water, whilst northern hemisphere temperate areas such as northern Europe and Japan, where water is plentiful, are importers.

The water footprint concept is already being enshrined in national policies as a way of accounting for water use. "Spain has just approved a regulation that requires water footprint analysis in River Basin Management Plans, which Member States need to send to the European Commission regularly from 2009, according to the Water Framework Directive," says Aldaya. "So it is now compulsory to calculate water footprints of the different socioeconomic sectors in Spain."