Indirect water and the water footprint: some facts and figures
The water footprint of an individual, company or country is defined as the total volume of freshwater used to produce the food and services that the individual, company or country consumes. The water footprint is generally expressed in terms of volume of water use per year.
Feb 17 2009
3 minutes
Since not all goods consumed in a country were also produced in that country, the water footprint consists of two parts: use of own, domestic water resources and use of water outside the country's borders. The water footprint includes both the water abstracted from surface water and the use of groundwater and so-called soil water (in agricultural production).
Indirect water is the water hidden in consumer goods and services. The production of goods and services requires water; the water used for agricultural and industrial production is called the indirect water of the product in question.
The global indirect water flow related to international trade in goods and services is equal to 1,6 million m³ per year. About 80% of this can be attributed to agricultural trade, while the remaining 20% comes from industrial production.
The production of 1 kilogram:
- rice requires 2.500 liters of water,
- corn requires 1.220 liters of water,
- flower requires 1.850 liters of water,
- beef requires 15.500 liters of water.
The production of one cup of coffee requires 130 liters of water, while the production of one glass of milk requires 210 liters of water.
Globally, water is saved when agricultural products are traded from regions with high water productivity to those with low water productivity. If the mainly importing countries were to obtain all the agricultural products they import from domestic production, they would need 1,6 million m³ more water. However, these products are made in the exporting countries with only 1,2 million m³ of water, saving global water resources by 400.000 m³ per year through import/export.
Per capita water consumption varies greatly depending on the diet or eating habits followed, ranging from 1 m³ per day for a survival diet, to 2,3 m³ per day for a vegetarian diet, to 3,6 m³ per day for a meat-based diet, typical in the United States.
Only 7% of China's water footprint of 700 m³ per capita per year falls outside China's borders, while 65% of Japan's water footprint of 1.150 m³ per capita per year is attributable to imported goods/services.
The United States is estimated to have an average per capita water footprint of 2.480 m³/capita/year, while the global average is 1.240 m³/capita/year.
This information was taken from the 2nd United Nations Water Development Report, “Water, a shared responsibility” and from the Water Footprint website of the UNESCO-IHE Institute for Water Education.
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