The Water Footprint is a new instrument for measuring the consumption of fresh water in agriculture and industry.
While the world worries about the diminishing reserves of fossil fuels and global warming, a much more valuable resource is often forgotten, a resource whose reserves are being rapidly depleted with potentially much more serious consequences for our planet: fresh water.
A number of studies have suggested that we are likely to run out of fresh water before we run out of oil, which makes it vital to examine how we use it.
So how is the water footprint of agriculture and industry measured?
The international standard is the Water Footprint Assessment (WFA), which is based on three components: blue, green and grey water. Blue water is freshwater that is used in agriculture and that does not return downstream after use, or in any case not immediately. Green water is rain water which is not absorbed by the soil and which eventually evaporates. Grey water is polluted by production processes.
An international water footprint standard, ISO 14046, has finally been established and was presented at World Water Week. The week was organised by Stockholm International Water Institute (SWI) and was held in Stockholm from 31 August to 5 September 2014.
All human productive activities leave a water footprint, and careful, ethical use of this crucial resource, even in areas where water is abundant, is vital.