Water, water everywhere?

You’ve heard of carbon footprints, right? You may even have calculated your own? But what about your water footprint? Have you ever considered how much ‘hidden’ water it takes to make your cup of coffee in the morning or indeed the tomato in your sandwich?

A report launched by WWF at this year’s World Water Week, held earlier this month in Stockholm, may just help give you some answers.

The report UK Water Footprint: the impact of the UK’s food and fibre consumption on global water resources tells the story of the water we use and where it comes from. Highlighting the impact of the UK’s consumption patterns on global water resources, the report found that the total water footprint of the UK is 102 Gm3 (billion cubic metres) per year. That works out as roughly 4, 645 litres per person per day.

While on average a single person in the UK wades their way through 150 litres of water a day by drinking, flushing and washing, around 30 times that amount is consumed by ‘virtual’ water – the water embedded in the food we eat, the clothes we wear and the numerous other items we consume. This is equivalent to someone having 50 baths or washing their clothes 75 times in a single day.

Virtual water refers to the volume of water required to produce a product. For example it takes 2,900 litres to ‘grow’ a cotton shirt.

A water footprint is the total virtual water content of products consumed by an individual, town or country. A water footprint consists of two parts: the use of local water and the use of global water resources.  The water used can be divided into blue water (water taken from ground or surface water resources), green water (water evaporated from soil moisture supplemented by rainfall) and grey water (defined in the WWF report as the amount of water rendered unusable by agricultural inputs, e.g. fertilisers).

Concluding that the UK is the sixth largest importer of water in the world, the report brings into sharp focus the dependency of UK lifestyles upon water imported from other nations.

Stuart Orr, WWF-UK’s water footprint expert, has said: “Only 38 per cent of the UK’s total water use comes from its own rivers, lakes and groundwater reserves. The rest is taken from water bodies in many countries across the world to irrigate and process food and fibre crops that people in Britain subsequently consume. What’s particularly worrying is that huge amounts of these products are grown in drier areas of the world where water resources are either already stressed or very likely to become so in the near future.”

WWF is seeking to encourage government, businesses and individuals to consider their water footprints and improve currently managed water systems, especially in places where water is scarce.

Mr Orr went on to say: “This is not just an issue for food and clothing companies, producers and retailers. Insurers and investors have a vested interest in encouraging efficiency of water use and security of water supply in an ever-thirstier world. Water is irreplaceable and climate change and population growth are only going to exacerbate the problem.”

To read the report click here

Check your water footprint

This article first appeared in the Ecologist August 2008

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