Water

Virtual Water

Up to now our discussion has been about working out how much water you use directly and what strategies you can use to reduce that direct water consumption, but there is a class of water that we do not consume directly. In much the same way as products we buy contain a greater or lesser amount of embodied energy, ie energy consumed in their production, water is consumed in the production of our food and industrial products. Such indirectly consumed water is usually referred to as embodied, embedded or virtual water.

Two guys who have done a lot of work with this concept, A.Y. Hoekstra and A.K. Chapagain, define virtual water as - "the volume of freshwater used to produce the product, measured at the place where the product was actually produced". It refers to the sum of the water use in the various steps of the production chain. Australians use 180 to 200 litres of water directly per day but it turns out that the industrial products and food we consume daily require almost 2192 litres to be consumed for each of us daily. Following are some examples of virtual water consumption for various food and industrial products -

So it seems that the water consumed indirectly on our behalf to produce our food and industrial products, virtual water exceeds the water we consume directly by a considerable margin. Direct water consumption is comparatively easy for us to directly impact, but even though we can’t directly affect the use of virtual water we can still impact on it with the most powerful tool we have – our spending habits.

What we buy or don’t buy and what we produce or conserve ourselves can certainly impact on our use of virtual water. Following are some hints you can implement to help reduce your virtual water consumption -

• Eat less meat, specifically beef
• Eat less dairy
• Drink tea or better, water instead of coffee
• Buy clothing second hand rather than new
• Repair and mend clothing rather than buying new
• Buy less “stuff”
• Buy second hand where possible
• Keep products for as long as possible before replacing them
• Grow your own food
• Waste less food

Unfortunately there is one piece of advice for reducing virtual water consumption which you see around the traps that I cannot in good conscience recommend – wear synthetic fabrics instead of natural fibre. There are so many good reasons to wear natural rather than synthetics, so let’s leave that there shall we?

The Water Footprint

Another way of looking at water consumption is the “National water footprint” which includes both direct and indirect water consumption and, is averaged to reflect the water consumption bya whole country. For example, Australia has a water footprint of 2,315 m3/capita/year or in other words each of us Australians consumes 2,315 tonnes of water annually (directly and indirectly). The global average is 1,385 m3/capita/year and the UK consumes 1,258 m3/capita/year while the US consumes 2,842 m3/capita/year. Clearly we have some work to do before we can get down to the global average or less, which is where we need to be, so use the information presented in these articles to help you reduce both your direct and indirect water consumption.

Back to part 1 - Introduction

Back to part 2 - Strategies