Embedded water (or virtual water) is the water used in the process of producing something (mainly food produce – 92%), as well as retailing and consuming, as it takes high levels of water to operate machinery, grow crops and produce electricity.
For example, we use around 150 litres per day for drinking, cleaning, sanitation use and cooking, however our embedded water intake is closer to 3500 litres per person per day (that’s approximately 1 million litres each year per person). The main demand of water is in the production of coffee, meat, cereal, alcohol (primarily wine), industrial products such as paper, even cars and other vehicles with an average demand of 500,000 – 1,000,000 litres!
A good example of embedded water usage in producing food is the water used to feed cattle, as producing 1 kg of beef requires 15,400 litres of water, this is a result of the amount of water required to grow the crops to feed the cattle, as well as the water for drinking, and the water contained in roughages (grass).
Types of Embedded Water
There are three types of embedded water, which are:
- Green Water – The water used by soil sourced directly from rainfall, which is considered to be free water and cause no threat due to being used directly where it falls and as a sustainable part of the water cycle.
- Blue Water – The water from surface and ground water (lakes and rivers) which can be used for both irrigation and by water companies to help meet the demands for water. Blue water is sustainable, however if the demand for blue water out-weight’s that of the supply then it will cause issues. Examples of this are if it is sourced from a long river with catchment at the top (e.g a mountainous region) and the water that fills that river not being enough to make up amounts of water removed, therefore lowering the river and in the long term stopping the river being a source of water.
- Grey Water – The water which is polluted during production, as well as the freshwater used to dilute the polluted water to make it acceptable to be entered into the natural water system. Common definitions of grey water are also waste water produced from homes, such as toilet, cleaning and washing water, fortunately these can usually enter the water cycle or be recycled fairly easily.
Why we need to reduce our embedded water usage?
As mentioned above, the high levels of water used in food produce and the manufacture of other products (cars and machinery) put a strain on our fresh water companies, making it harder to source and provide fresh water for the 7 billion people around the world.
With 92% being used in the food industry, the pressure applied to the water system is therefore too much and will eventually start to decrease the water available from the water cycle and will also affect the cost of fresh water. This also has an effect on other countries as 70% of embedded water comes from other nations due to imported goods.
This also affects countries without easy access to water, with 1 billion people still not having access to fresh drinking water and even more not having access to a tap.
What we can do to help?
The main effect we can have on the reduction of embedded water would be to reduce the usage and consumption of certain products as parts of our daily lives. However, knowing of alternatives can have a big effect, so the information below provides examples of alternatives to the main consumers of embedded water:
The production of meat for human consumption uses very high levels of embedded water, for example, 1 kg of meat requires 15,400 litres of water to produce. If everyone cuts down on meat consumption, it will benefit the water cycle by lowering the demand of water, possibly by having a meat free day each week. If you cannot go without, then possibly be selective with your choice of meat, as beef production uses the highest levels of embedded water, while sheep and lamb require about 10,400 litres, and chicken and pork has a much smaller litre capacity of between 5,500 – 6,000 litres per 1kg.
Cereal grains also account for a high amount of embedded water usage, due to being 60% of global food production. White rice requires a total of 2,500 litres altogether to be turned into the white rice, whereas maize requires 1,220 litres and wheat requires 1,827 litres, so this is a case of considering which has the least effect on the water demand, and possibly finding an alternative. The location where cereal is produced also has a large effect, to produce maize cereal in India (2,540 litres) would require nearly 4x the amount required in the US (780 litres).
Alcohol varies between the types, so knowing which type has a lower demand allows you to make the small changes even when simply having a drink. An example of this would be wine compared to beer, as a 700 mm glass of wine uses around 870 litres, beer however uses 208 litres for the equivalent, making it the better choice for reducing your footprint.
Some other items worth considering are:
- Paper – 10 litres per sheet
- Jeans – 10,850 litres per sheet
- Cotton T Shirt – 4,100 litres
- 200mm glass of milk – 200 litres
- 1 whole coconut – 2500 litres
- Orange – 50 litres
- 1 Large slice of cheese – 2500 litres
- One pot of coffee – 840 litres
- One pot of tea – 90 litres
With everybody following simple steps like these, it will have a very positive effect on the demand for water and help ease the pressure on fresh water companies.