The concept of virtual water takes into account the total amount of water used during the manufacturing process of a good. For example, a pair of jeans is hardly made of water. However, the cotton plant from which the jeans are made requires a great deal of water, which is why the manufacturing process of one pair of jeans consumes a considerable amount of water. In addition, there is the water consumption of the manufacturer, the retailer and the end consumer. In many cases, water is polluted during each individual process.
Examples of Virtual Water
1kg cotton = 10,000 litres of water
1kg beef = 15,400 litres of water
1kg tomatoes = 214 litres of water
1 cup of coffee = 140 litres of water
1 computer = 20,000 litres of water
1L bottled water = 4 litres of water
The quantification of virtual water allows accurate and practical usage. It enables calculations for global streams of virtual water related to the international water trade. In that way it is possible to get a better understanding of the consequences of global trade on local water systems and to take the necessary measures.
The world bank estimates that 20 percent of the global industrial water pollution occurs due to colouring and other treatments of textiles.
Global Water Consumption by Sector
The agricultural sector consumes by far the most water. This includes the production of plant and animal products. Irrigation accounts for an average of 70% of global water use. Industry accounts for 22% and private households for only 8%. Likewise, agriculture is one of the main causes of water pollution through the excessive release of nutrients, nitrates or pesticides into ground and surface waters. The volume of water consumption varies from product to product.
By far the largest part of water consumption takes place – usually invisible for us – outside our households in the manufacturing of goods. As consumers, however, we can also exert influence here.
Switzerland: The Water Castle of Europe
Switzerland has tremendous water resources. 5% of Europe's water resources are stored within the relatively small Swiss land area. Glaciers, lakes and groundwater store large volumes of accessible fresh water, and the country's geography results in sufficient precipitation. Today, Switzerland has the privilege of easily covering its internal water footprint. However, this is only a small part of our total water footprint.
Switzerland: A Water Importing Country
Aside from water, Switzerland has comparatively few natural resources. It therefore imports goods from all over the world to cover its consumption needs. In 2015, the import balance was 52 million tonnes of goods worth CHF 244 billion. Many of these goods conceal an enormous amount of water. Despite its large water resources, Switzerland is therefore a water importing country: around 80% of our water footprint is created abroad. And this footprint is growing rapidly with increasing globalisation. Between 1996 and 2011, the water footprint of goods consumed in Switzerland increased by 60%.
Many goods originate from regions with physical or economic water shortages. As a result, our consumption and standard of living are putting pressure on the condition of local water resources and qualities around the world.
Switzerland contributes indirectly to falling groundwater levels and water pollution in countries that are trading partners of Switzerland.
The mere volume is not sufficient to indicate the impact of the production of goods on local water resources and local water quality, however. The type of water consumption and the ratio of demand to naturally available water resources are much more important. As a result, we distinguish between three types of water consumption.
Green water is the volume of rainwater consumed. In most cases it is the most sustainable type of water, as the annual rainfall volume only decreases with major changes in weather patterns.
Blue water refers to the volume of surface water and groundwater consumed. If withdrawal exceeds the natural inflow, e.g. by rain or melt water, this can have considerable effects on the entire ecosystem.
Grey water is the volume of fresh water needed to absorb the levels of pollutants that occur during the production process, so that the water meets recognised quality standards. A large grey footprint therefore means a high level of water pollution.
Consequences of Water Consumption
Blue and grey water are of particular importance as these have a large impact on the water and ecosystem of the region in the event of overuse or poor management. If the use of blue water, i.e. lake water, river water and groundwater, exceeds the natural inflow, water levels drop. This not only burdens the local ecosystem, but leads to water shortages for local residents due to the blue water being used as a source of drinking water. Distribution problems arise, usually affecting the poorest part of the population first. Grey water is just as problematic: the entry of polluted, mostly untreated water into the environment places an enormous burden on local ecosystems.
Blue and grey water are potentially the most significant types of water consumption. Excessive extraction of groundwater and surface water or uncontrolled pollution of water bodies have enormous impacts on ecosystems and residents.
Global Consumption - Global Responsibility
Our daily consumption connects us with the entire world. Imported goods leave a footprint along the entire supply chain, from production and distribution to consumption and disposal. This gives rise to a global responsibility for the social, ecological and economic circumstances of our trading partners.
One third of all foodstuffs worldwide is currently produced in areas experiencing high or extremely high water stress.