Contact

Drought-Proof Diet

There are some great tasting food recipes people can eat that are both healthy for the body and good for an increasingly water stressed planet.

Why go to the trouble? Because how we choose to eat right here and right now will affect the lives of people and habitats elsewhere on the planet and in years ahead.

Take the following numbers, estimated by from Waterwise...

Importance of embedded water in food

Water embedded in food represents the majority (65%) of total water use. While the exact figure may be disputed it is clear that significant amounts of water are used in the production and processing of food products. The amounts vary by food category. By way of illustration, a number of common food products are presented below with an estimate of their embedded water for a given weight or volume.

Estimates of water embedded in different products

Portion Litres Portion Litres Portion Litres
Pint of beer, 568ml 170 Cup of coffee, 125ml 140 Glass of orange juice, 200ml 170
Glass of milk, 200ml 200 Cup of instant coffee, 125ml 80 Glass of apple juice, 200ml 190
Cup of tea, 250ml 35 Glass of wine, 125ml 120 Orange, 100g 50
Slice of bread, 30g 135 Bread with cheese, 30g + 10g 90 Bag of potato crisps, 200g 185
Egg, 40g 135 Tomato, 70g 13 Hamburger, 150g 2400
Potato, 100g 25 Apple, 100g 70 Bovine leather shoes 8000
Sheet of A4, 80 g/m² 10 Cotton tee-shirt, medium 500g 4100 Microchip, 2g 32

Source: Waterwise

It is clear that different types of food require different amounts of water to produce them and so embedded water differs greatly by category. It is important to understand how these figures have been calculated. The hamburger is taken as the example.

Example of embedded water in beef production

Example of embedded water in beef production (Source: Waterwise)

Source: Waterwise

Again, while the actual figures may be challenged water is clearly required in producing cattle feed (grain and roughage in this case), providing drinking water for cattle and in other services during production and processing.

The water embedded in products is a growing area of awareness. In the UK the Food Industry Sustainability Strategy Champions’ Group on water concludes that “Both retailers and manufacturers should have regard to the ‘embedded water’ in the products they source, the associated carbon, and the potential environmental impact these factors may have, particularly on the products’ countries of origin”.
 

And from GDRC

  • Water Footprint

    A water footprint is quite simply the volume of water used. At the individual level, this is expressed in litres. But at the national level, this becomes complex - The water footprint of a nation is equal to the use of domestic water resources, minus the virtual water export flows, plus the virtual water import flows.

    The total ‘water footprint’ of a nation is a useful indicator of a nation’s call on the global water resources. The water footprint of a nation is related to dietary habits of people. High consumption of meat brings along a large water footprint. Also the more food originates from irrigated land, the larger is the water footprint. Finally, nations in warm climate zones have relatively high water consumption for their domestic food production resulting in a larger water footprint. At an individual level, it is useful to show the footprint as a function of food diet and consumption patterns.

    Ten litres of orange juice needs a litre of diesel fuel for processing and transport, and 220 litres of water for irrigaton and washing the fruit. The water may be a renewable resource, but the fuel is not only irreplaceable but is a pollutant, too.
    Behind that morning cup of coffee is 140 litres of water used to grow, produce, package and ship the beans.
    1 cup of coffee needs 140 litres of water.
    1 litre of milk needs 800 litres of water.
    1 kg of wheat needs 1100 litres of water.
    1 kg of rice needs 2300 litres of water.
    1 kg maize needs 900 litres of water.

    • The production of one kilogram of beef requires 22 thousand litres of water.
    • To produce one cup of coffee we need 140 litres of water.
    • The water footprint of China is about 775 cubic meter per year per capita. Only about 3% of the Chinese water footprint falls outside China.
    • Japan with a footprint of 1100 cubic meter per year per capita, has about 60% of its total water footprint outside the borders of the country.
    • The USA water footprint is 2600 cubic meter per year per capita.
    Source: UNESCO-IHE - Water Footprint


  • Virtual Water

    Virtual water is the amount of water that is embedded in food or other products needed for its production. Trade in virtual water allows water scarce countries to import high water consuming products while exporting low water consuming products and in this way making water available for other purposes [World Water Council].

    For example, the virtual water content (in m3/ton) for potatoes is 160. Others examples - maize=450; milk=900; wheat=1200; soybean=2300; rice=2700; poultry=2800; eggs=4700; cheese=5300; pork=5900; and beef=16000.

    Showing people the ‘virtual water’ content of various consumption goods will increase the water awareness of people.


    People consume water not only when they drink it or take a shower. In 1993, Professor John Allan (2008 Stockholm Water Prize Laureate), strikingly demonstrated this by introducing the "virtual water" concept, which measures how water is embedded in the production and trade of food and consumer products.

    Behind that morning cup of coffee are 140 litres of water used to grow, produce, package and ship the beans. That is roughly the same amount of water used by an average person daily in England for drinking and household needs. The ubiquitous hamburger needs an estimated 2,400 litres of water. Per capita, Americans consume around 6,800 litres of virtual water every day, over triple that of a Chinese person.

    Virtual water has major impacts on global trade policy and research, especially in water-scarce regions, and has redefined discourse in water policy and management. By explaining how and why nations such as the US, Argentina and Brazil 'export' billions of litres of water each year, while others like Japan, Egypt and Italy 'import' billions, the virtual water concept has opened the door to more productive water use.

    National, regional and global water and food security, for example, can be enhanced when water intensive commodities are traded from places where they are economically viable to produce to places where they are not. While studying water scarcity in the Middle East, Professor Allan developed the theory of using virtual water import, via food, as an alternative water "source" to reduce pressure on the scarcely available domestic water resources there and in other water-short regions. [SIWI - www.siwi.org]


Comments