Virtual water
Encyclopedia
Virtual water refers, in the context of trade, to the water used in the production of a good or service. For instance, it takes 1,300 cubic meters of water on average to produce one metric tonne of wheat. The precise volume can be more or less depending on climatic conditions and agricultural practice. Hoekstra and Chapagain have defined the virtual-water content of a product (a commodity, good or service) 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.

Professor John Anthony Allan
John Anthony Allan
John Anthony Allan is a British geographer. He was awarded the Stockholm Water Prize in 2008 for his revolutionary virtual water concept. Although being an emeritus of the School of Oriental and African Studies and King's College London of the University of London, he still acts as a teaching...

 from King’s College London and the School of Oriental and African Studies
School of Oriental and African Studies
The School of Oriental and African Studies is a public research university located in London, United Kingdom and a constituent college of the University of London...

 was the creator of the virtual water concept, which measures how water is embedded in the production and trade of food and consumer products. For his contributions he was awarded the 2008 Stockholm Water Prize
Stockholm Water Prize
Presented annually since 1991, the Stockholm Water Prize is a prestigious award that recognises outstanding achievements in water related activities...

. In his awarding, the Stockholm International Water Institute (SIWI) stated that "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."

Allan (2005) stated: "The water is said to be virtual because once the wheat is grown, the real water used to grow it is no longer actually contained in the wheat. The concept of virtual water helps us realize how much water is needed to produce different goods and services. In semi-arid and arid areas, knowing the virtual water value of a good or service can be useful towards determining how best to use the scarce water available."

There are, however, significant deficiencies with the concept of virtual water that mean there is a significant risk in relying on these measures to guide policy conclusions. Accordingly, Australia's National Water Commission considers that the measurement of virtual water has little practical value in decision making regarding the best allocation of scarce water resources.

Agricultural products

It is essential to recognize that virtual water is cumulative. To produce one kilogram of wheat about 1000 liters of water are needed, but for beef about 15 times as much is required. The majority of the water that we consume is embedded in food:
  • the production of 1 kg wheat
    Wheat
    Wheat is a cereal grain, originally from the Levant region of the Near East, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...

     costs 1,300 L water
  • the production of 1 kg eggs
    Egg (food)
    Eggs are laid by females of many different species, including birds, reptiles, amphibians, and fish, and have probably been eaten by mankind for millennia. Bird and reptile eggs consist of a protective eggshell, albumen , and vitellus , contained within various thin membranes...

     costs 3,300 L water
  • the production of 1 kg broken rice
    Rice
    Rice is the seed of the monocot plants Oryza sativa or Oryza glaberrima . As a cereal grain, it is the most important staple food for a large part of the world's human population, especially in East Asia, Southeast Asia, South Asia, the Middle East, and the West Indies...

     costs 3,400 L water
  • the production of 1 kg beef
    Beef
    Beef is the culinary name for meat from bovines, especially domestic cattle. Beef can be harvested from cows, bulls, heifers or steers. It is one of the principal meats used in the cuisine of the Middle East , Australia, Argentina, Brazil, Europe and the United States, and is also important in...

     costs 15,500 L water

Household products

Not only is there virtual water in food, but it is in various products in common use:
  • Jeans
    Jeans
    Jeans are trousers made from denim. Some of the earliest American blue jeans were made by Jacob Davis, Calvin Rogers, and Levi Strauss in 1873. Starting in the 1950s, jeans, originally designed for cowboys, became popular among teenagers. Historic brands include Levi's, Lee, and Wrangler...

     (1000g) contain 10,850 liters of embedded virtual water
  • A cotton shirt (medium sized, 500 gram) contains 4,100 liters of water
  • A disposable diaper
    Diaper
    A nappy or a diaper is a kind of pant that allows one to defecate or urinate on oneself discreetly. When diapers become soiled, they require changing; this process is often performed by a second person such as a parent or caregiver...

     (75g) contains 810 liters of water
  • A bed sheet (900g) contains 9,750 liters of water

Industrial products

Industrial goods also contain embodied water. One needs to understand how internal water resources are being used to produce cars, bicycles, teacups, and the like - particularly because industry usually uses only blue water for production (though rainwater harvesting is becoming more common). On average, a 1.1 tonne passenger car has about 400,000 liters of water embedded in it. This fact is compiled from several different resources including the UNESCO-IHE
UNESCO-IHE
The UNESCO-IHE Institute for Water Education is an international institute for water education that was created in 2003 from the previous IHE. This in turn grew out of the International Course in Hydraulic Engineering , whose name was changed in 1976 to International Institute for Hydraulic and...

 study and the Australian Food & Grocery 2003. Another source suggests Australian cars require one million litres of water, though this is from using a different method. The construction of a house, using a combination of methods, requires about 6 million litres of water.

The three colours of a product’s virtual-water content

The virtual-water content of a product consists of three components, called green, blue and grey components.

The ‘green’ virtual-water content of a product is the volume of rainwater that evaporated during the production process. This is mainly relevant for agricultural products, where it refers to the total rainwater evaporation from the field during the growing period of the crop (including transpiration by the plants and other forms of evaporation).

The ‘blue’ virtual-water content of a product is the volume of surface water or groundwater that evaporated as a result of the production of the product. In the case of crop production, the blue water content of a crop is defined as the sum of the evaporation of irrigation water from the field and the evaporation of water from irrigation canals and artificial storage
reservoirs (although for practical reasons the latter component has been left out from our studies). In the cases of industrial production and domestic water supply, the blue water content of the product or service is equal to the part of the water withdrawn from ground or surface water that evaporates and thus does not return to the system where it came from.

The ‘grey’ virtual-water content of a product is the volume of water that becomes polluted during its production. This can be quantified by calculating the volume of water required to dilute pollutants emitted to the natural water system during its production process to such an extent that the quality of the ambient water remains beyond agreed minimum water quality standards.

The distinction between green and blue water originates from Falkenmark (2003). It is relevant to know the ratio of green to blue water use, because the impacts on the hydrological cycle are different. Both the green and blue components in the total virtual-water content of a product refer to evaporation. The grey component in the total virtual-water content of a product refers to the volume of polluted water. Evaporated water and polluted water have in common that they are both ‘lost’, i.e. in first instance unavailable for other uses. It is said ‘in first instance’ because evaporated water may come back as rainfall above land somewhere else and polluted water may become clean in the longer term, but these are considered here as secondary effects that will never take away the primary effects.

Impact of virtual water

Once all the virtual water is added up, what is eaten and used in products of consumption, along with the daily use of water out of the tap, gives a better idea of a water footprint. Water footprints are used to give nations a better consumption-based indicator of water use. However, this water use indicator is, by definition, a loose indicator or actual water loss of a country. Since this water is usually kept in the region from which it was "used," the water use impact is generally perceived to be negligible.

Trade

Virtual water trade refers to the idea that when goods and services are exchanged, so is virtual water. When a country imports one tonne of wheat instead of producing it domestically, it is saving about 1,300 cubic meters of real indigenous water. If this country is water-scarce, the water that is 'saved' can be used towards other ends. If the exporting country is water-scarce, however, it has exported 1,300 cubic meters of virtual water since the real water used to grow the wheat will no longer be available for other purposes. This has obvious strategic implications for countries that are water-constrained such as those found in the Southern African Development Community (SADC) area

Daniel Zimmer, Director of the World Water Council
World Water Council
The World Water Council is an international think tank founded in 1996, with its headquarters in Marseilles, France. It has 323 members from the private sector , government ministries, academic institutions, international financial institutions , the UN...

, in his presentation at the session on "virtual water trade and geopolitics" at the 2003 World Water Forum
World Water Forum
Every three years the World Water Council organizes a World Water Forum in close collaboration with the authorities of the host country. The World Water Forum is the largest international event in the field of water—over 30,000 participants from more than 190 countries attended the last...

 in Kyoto
Kyoto
is a city in the central part of the island of Honshū, Japan. It has a population close to 1.5 million. Formerly the imperial capital of Japan, it is now the capital of Kyoto Prefecture, as well as a major part of the Osaka-Kobe-Kyoto metropolitan area.-History:...

:
"The contrast in water use can be noticed between continents. In Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

, people consume an average of 1,400 litres of virtual water a day, while in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 and North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, people consume about 4,000 litres. About 70 per cent of all water used by humans goes into food production. [...]
"Among the biggest net exporter countries of virtual water are the U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...

, Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

, India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

, Vietnam
Vietnam
Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...

, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 and Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

. Some of the largest net import countries are Sri Lanka
Sri Lanka
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...

, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

, the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

, South Korea
South Korea
The Republic of Korea , , is a sovereign state in East Asia, located on the southern portion of the Korean Peninsula. It is neighbored by the People's Republic of China to the west, Japan to the east, North Korea to the north, and the East China Sea and Republic of China to the south...

, China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

, Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

, Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...

, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 and Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

."


Water-scarce countries like Israel discourage the export of oranges (relatively heavy water guzzlers) precisely to prevent large quantities of water being exported to different parts of the world.

In recent years, the concept of virtual water trade has gained weight both in the scientific as well as in the political debate. The notion of the concept is ambiguous. It changes between an analytical, descriptive concept and a political induced strategy. As an analytical concept, virtual water trade represents an instrument which allows the identification and assessment of policy options not only in the scientific but also in the political discourse. As a politically induced strategy the question is, whether virtual water trade can be implemented in a sustainable way, whether the implementation can be managed in a social, economical and ecological fashion, and for which countries the concept offers a meaningful option.

The data that underlie the concept of virtual water can readily be used to construct water satellite accounts, and brought into economic models of international trade such as the GTAP
GTAP
GTAP is a global network of researchers who conduct quantitative analysis of international economic policy issues, especially trade policy. They cooperate to produce a consistent global economic database, covering many sectors and all parts of the world...

 Computable General Equilibrium Model. Such a model can be used to study the economic implications of changes in water supply or water policy, as well as the water resource implications of economic development and trade liberalisation.

In sum, virtual water trade allows a new, amplified perspective on water problems: In the framework of recent developments from a supply-oriented to a demand-oriented management of water resources it opens up new fields of governance
Governance
Governance is the act of governing. It relates to decisions that define expectations, grant power, or verify performance. It consists of either a separate process or part of management or leadership processes...

 and facilitates a differentiation and balancing of different perspectives, basic conditions and interests. Analytically the concept enables to distinguish between global, regional and local levels and their linkages. This means, that water resource problems have to be solved in problemsheds if they cannot be successfully addressed in the local or regional watershed. Virtual water trade can thus overcome the hydro-centricity of a narrow watershed view. According to the proceedings of a 2006 conference in Frankfurt
Frankfurt
Frankfurt am Main , commonly known simply as Frankfurt, is the largest city in the German state of Hesse and the fifth-largest city in Germany, with a 2010 population of 688,249. The urban area had an estimated population of 2,300,000 in 2010...

, Germany, it seems reasonable to link the new concept with the approach of Integrated Water Resources Management
Integrated Water Resources Management
Integrated Water Resources Management has been defined by the Technical Committee of the Global Water Partnership as "a process which promotes the coordinated development and management of water, land...

.

Limitations of the virtual water measure

Key shortcomings of virtual water measures are that the concept:
  1. Relies on an assumption that all sources of water, whether in the form of rainfall or provided through an irrigation system, are of equal value.
  2. Implicitly assumes that water that would be released by reducing a high water use activity would necessarily be available for use in a less water-intensive activity. For example, the implicit assumption is that water used in rangeland beef production would be available to be used to produce an alternative, less water-intensive activity. As a practical matter this may not be the case, nor might the alternatives be economic.
  3. Fails as an indicator of environmental harm nor does it provide any indication of whether water resources are being used within sustainable extraction limits. The use of virtual water estimates therefore offer no guidance for policy makers seeking to ensure that environmental objectives are being met.


The deficiencies with the concept of virtual water mean that there is a significant risk in relying on these measures to guide policy conclusions. Accordingly, Australia's National Water Commission considers that the measurement of virtual water has little practical value in decision making regarding the best allocation of scarce water resources.

Other limitations more specific to the MENA (Middle East & North Africa) region include:
  1. In MENA rural societies, farmers are by tradition politically influential and would prohibit new policies for water allocation. Reallocating the water resources adds a huge burden on the farmers especially when a large portion of those farmers use their land for their own food consumption which happens to be their only source of food supply.
  2. Importing food could pose the risk of further political dependence. The notion of "Self Sufficiency" has always been the pride of the MENA region.
  3. The use of virtual water lies in the religious regulations for charging for water. According to Al-Bukhari, Prophet Mohammad’s teachings, the Prophet said: “People are partners in three: Water,Herbs and Fire” (referring to basic energy resources). Therefore, and because farmers are generally poor and rain water, rivers and lakes are like a gift from God,the MENA countries might find it difficult to charge the farmers the full cost for water.

Embodied energy

Some researchers have attempted to use the methods of energy analysis, which aim to produce embodied energy
Embodied energy
Embodied energy is defined as the sum of energy inputs that was used in the work to make any product, from the point of extraction and refining materials, bringing it to market, and disposal / re-purposing of it...

 estimates, to derive virtual, or embodied water estimates.

See also

  • Peak water
    Peak water
    The term Peak Water has been put forward as a concept to help understand growing constraints on the availability, quality, and use of freshwater resources...

  • Water footprint
    Water footprint
    The water footprint of an individual, community or business is defined as the total volume of freshwater used to produce the goods and services consumed by the individual or community or produced by the business. Water use is measured in water volume consumed and/or polluted per unit of time. A...

  • Water management
    Water management
    Water management is the activity of planning, developing, distributing and managing the optimum use of water resources. In an ideal world. water management planning has regard to all the competing demands for water and seeks to allocate water on an equitable basis to satisfy all uses and demands...

  • Deficit irrigation
    Deficit irrigation
    Deficit irrigation is a watering strategy that can be applied by different types of irrigation application methods. The correct application of DI requires thorough understanding of the yield response to water and of the economic impact of reductions in harvest...

  • water resource policy
    Water resource policy
    This article is about water resource policy, its institutions, the policy making processes and major subdivisions rather than implementation or hydrology, irrigation, geography, fisheries management, implementation, the management of specific water projects or the purchase, ownership and conveyance...


Further reading


External links

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