The water that you don’t see that goes into making things is called the ‘Water Footprint’, or ‘Virtual Water’.
In this guide, we explain what those terms might mean, and outline other important information to consider.
Summary – Water Footprints, & Virtual Water
- A water footprint is all the direct and indirect water that goes into making a product or delivering a service
- For example, when you eat rice or a piece of fruit, there is water that has gone into growing those food items. When you drive a car, there is water used in the manufacturing, as well as to wash the car. There is even water used to refine the gasoline that a car runs on.
- Even importing products from other countries carries a water footprint, although it should be noted it’s often the country doing the exporting that have their water supplies being depleted or impacted (importing countries can save water this way)
- A water footprint is measured in terms of the volume of water consumed, evaporated and polluted (including contamination) during manufacture and production process, and can be extended into operation or use.
- The type of water in the water footprint matters … for example, rainfed crops are obviously going to carry an eco friendly benefit that heavily irrigated (with fresh water reserves) crops probably aren’t.
- There’s different ways a water footprint can be measured or expressed
*Note – measuring and expressing a water footprint can’t be a 100% exact science because knowledge of processes and data given to researches is often incomplete. It’s more of an indicator we can use to pick up trends and patterns on what products and services we can focus on in order to conserve or be more efficient with water use (or even water contamination, pollution and re-use/recycling).
What Is A Water Footprint?
Water footprints…reveal water use patterns, from the individual level all the way to the national level, and in all the processes involved in manufacturing and producing our goods.
A water footprint is measured in terms of the volume of water consumed, evaporated and polluted (including contamination) during manufacture and production.
Water footprints can be calculated for individuals, households, businesses and countries.
Water footprints give everyone – from individuals to business managers to public officials – a solid frame of reference that helps the world be more efficient and sustainable with water use. By understanding our water footprints, we can appreciate the role water plays in everyone’s lives.
The water footprint measures the amount of water used to produce each of the goods and services we use. It can be measured for a single process, such as growing rice, for a product, such as a pair of jeans, for the fuel we put in our car, or for an entire multi-national company. The water footprint can also tell us how much water is being consumed by a particular country – or globally – in a specific river basin or from an aquifer.
The water footprint is a measure of humanity’s appropriation of fresh water in volumes of water consumed and/or polluted.
The water footprint allows us to answer a broad range of questions for companies, governments and individuals. For example:
- where is the water dependence in my company’s operations or supply chain?
- how well are regulations protecting our water resources?
- how secure are our food or energy supplies?
- can I do something to reduce my own water footprint and help us manage water for both people and nature?
Depending on the question you are asking, the water footprint can be measured in cubic metres per tonne of production, per hectare of cropland, per unit of currency and in other functional units. The water footprint helps us understand for what purposes our limited freshwater resources are being consumed and polluted. The impact it has depends on where the water is taken from and when. If it comes from a place where water is already scarce, the consequences can be significant and require action.
Different Types Of Water Footprints – Blue, Green & Grey
There are Blue, Green & Grey water footprints, which are considered the different types of water footprints:
- Blue Water Footprint: The amount of surface water and groundwater required (evaporated or used directly) to produce an item.
- Green Water Footprint: The amount of rainwater required (evaporated or used directly) to make an item.
- Grey Water Footprint: The amount of freshwater required to dilute the wastewater generated in manufacturing, in order to maintain water quality , as determined by state and local standards.
The water footprint has three components: green, blue and grey. Together, these components provide a comprehensive picture of water use by delineating the source of water consumed, either as rainfall/soil moisture or surface/groundwater, and the volume of fresh water required for assimilation of pollutants.
The water footprint looks at both direct and indirect water use of a process, product, company or sector and includes water consumption and pollution throughout the full production cycle from the supply chain to the end-user.
It is also possible to use the water footprint to measure the amount of water required to produce all the goods and services consumed by the individual or community, a nation or all of humanity. This also includes the direct water footprint, which is the water used directly by the individual(s) and the indirect water footprint – the summation of the water footprints of all the products consumed.
- Green water footprint is water from precipitation that is stored in the root zone of the soil and evaporated, transpired or incorporated by plants. It is particularly relevant for agricultural, horticultural and forestry products.
- Blue water footprint is water that has been sourced from surface or groundwater resources and is either evaporated, incorporated into a product or taken from one body of water and returned to another, or returned at a different time. Irrigated agriculture, industry and domestic water use can each have a blue water footprint.
- Grey water footprint is the amount of fresh water required to assimilate pollutants to meet specific water quality standards. The grey water footprint considers point-source pollution discharged to a freshwater resource directly through a pipe or indirectly through runoff or leaching from the soil, impervious surfaces, or other diffuse sources
- Green Water Footprint (Rainfall) – Precipitation/rainfall. Is stored temporarily as surface or soil moisture and used directly on crops
- Grey Water Footprint (pollution arising from production of a good or service) – Water required to treated polluted run off and production water to acceptable levels
- Blue Water Footprint (Irrigation) – Water stored in rivers, lakes or aquifers, and used during irrigation and production
- The overwhelming majority of water in the water footprint of some common foods/crops is green water, followed by blue, followed by grey
- Conventionally, consumption of green water — essentially free to use in most cases, and much of which would be consumed by noncrop plants anyhow — is preferable over blue water, which depletes aquifers and impacts ecosystems if overused.
- Unequal distributions of water and arable land, as well as climate can impact how states, and provinces within a country, or countries themselves use green, grey and blue water
- Most provinces in China consume predominantly green water for agricultural production, but that volumes of green and blue water required to raise given crops or livestock vary widely across the country. Reflecting the dry climate in northern China during the growing season, for example, provinces like Ningxia, Xinjiang and Inner Mongolia — net exporters of commodities like soybeans and corn — use large amounts of blue water for irrigation.
- Inner Mongolia, in particular, is one of the top exporters of corn, yet relies on irrigation for a far greater proportion of the water needed to grow it — more than 50 percent — than other corn-exporting provinces do. This “means that dry, irrigation-intensive provinces tend to export [virtual] water to less water-intensive” provinces
- Policy affects large-scale reorganizations of crop growth or subsidies to different provinces. There are many social, economic and environmental factors that come into play when making policy changes that affect water use
You can see examples of how Green, Blue and Grey water is used separately for certain products here:
What Is ‘Virtual Water’ Or ‘Hidden Water’?
Virtual water or hidden water is the water you don’t see or hear about that goes into the entire process making something – materials, production and all.
For example, with a cotton shirt, not only is water used to grow cotton, but it can also be used in the manufacturing stage, like during wet processing for example with bleaching, printing, and dyeing.
Another example is that separate materials are used to make a car – steel, rubber, plastic, leather, foam etc. Not only is water used in the manufacture process for cleaning, cooling and so on when the car is being put together, but it is used for the raw materials that make up the car (and even in the process of extracting or making those materials).
- Millions of gallons of water goes into the products Americans buy, use and throw away
- It’s in the production and manufacturing of everyday materials like paper, plastic, metal and fabric
- Water goes into both the raw materials and goods we all use and consume
- There is such a thing as ‘virtual water’ – which is water that is not felt or seen but is used for the production processes for many different raw materials and finished products. Both the water we can see and the water we don’t see, and both direct water and indirect water, must be accounted for for the real water footprint of products and raw materials
- There is such a thing as a grey water footprint, and smartphones in particular have virtual water associated with their manufacturing (grey water footprint)
- With smartphones in particular…
- Phones are composed of many pieces created in multiple steps, and each step consumes water. Numerous resources, materials and parts go into smartphone manufacturing, including rare earth metals (e.g., lithium), tin, glass and plastics. The supply chains for these materials stretch around the world to places like Indonesia, the Philippines and China. Production might include steps like mining for precious metals, creating synthetic chemicals for glue and plastic and assembling and packaging. Collectively, the water associated with each step adds up to the blue water footprint.
- In addition, manufacturing the parts creates wastewater that is released into surrounding waterways. Those waterways often have pollution limits that manufacturers must meet before they can send their wastewater down the pipe and into the waterway. The water used to clean and dilute the wastewater adds up to the grey water footprint, and in the case of the smart phone, makes up the largest portion of its total water footprint.
- When the water required for all the steps to make a smart phone is added up, the water footprint of the production of a single phone is an estimated 3,190 gallons.
Closely linked to the water footprint concept is the virtual water concept. Virtual water is defined as the volume of water required to produce a commodity or service.
- The virtual water concept applies not just to crops, but to fodder-fed livestock, manufactured items, energy and any goods or services — agricultural, industrial or otherwise — that consume freshwater during their production.
- Virtual water volumes, for example, are used to calculate water footprints — estimates of direct and indirect water use by producers and consumers — which have been used as an outreach tool to raise awareness of sustainability concerns. And both virtual water analyses and water footprints have been cited by many as potentially valuable tools for influencing trade and water policies to promote conservation and combat water scarcity.
- Virtual water trade (also known as trade in embedded or embodied water) refers to the hidden flow of water if food or other commodities are traded from one place to another.
- For instance, it takes 1,340 cubic meters of water (based on the world 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.
- 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
Direct & Indirect Water Footprint
Direct water is used at the level or stage that is being looked at, whilst indirect water has been used at a previous stage.
The difference between direct and indirect water can be seen at the household level clearly:
- Direct water – water used for drinking, bathing, cleaning, gardening and lawns etc.
- Indirect water – households also eat food and use electricity. Water is used at the farm level for irrigation, and at the power plant level for electricity generation. The household level does not see this war usage, even though they get the end product – food, or electricity
Businesses may also use water directly in factories for cooling, cleaning and so on, but they may also use materials and supplies such as metals, papers and plastics that have indirect water usage to extract or make them, before they were delivered to the factory.
There’s also this explanation:
- Direct water usage – which means bringing water into a manufacturing facility for your industrial process
- Indirect water usage – when a manufacturing facility is buying items from the supply chain that were manufactured by someone else using water, then incorporating those materials into the finished product.
- In terms of direct water usage, nobody beats the agriculture and power-generation industries, which together are responsible for 90 percent of direct water withdrawals. Yet a majority of water usage (about 60 percent) is indirect.
- About 96 percent of industry sectors use more water indirectly than directly in their supply chains.
Limitations Of The Water Footprint Concept, & Virtual Water
The consensus seems to be that whilst a water footprint or virtual water statistics can provide some perspective on water use, it can’t be used a sole indicator of water use.
It may be best used in an integrated approach with other water usage stats and information, and weighing it up with local, national and global political, social, economic and other factors.
- Many researchers stress a cautious approach, suggesting that virtual water is a useful, albeit limited tool for addressing water issues – like water scarcity and sustainability (China is one such country facing water scarcity issues).
- Others contend that calculations of virtual water are inconsistent or inaccurate, that volumetric indicators ignore important local socioeconomic factors related to water consumption, and that, if used to guide trade or water allocation policies, they could end up hurting the very populations at risk from water scarcity.
- See also http://www.globalwaterforum.org/2012/05/14/virtual-water-some-reservations/, and http://www.globalwaterforum.org/2013/10/22/water-footprints-policy-relevant-or-one-dimensional-indicators/ for more reasons that the virtual water footprint concept can be limited
- Some countries like Spain and India have used the concept for help in forming regulations and policies
- However, Australia’s National Water Commission concluded “that the measurement of virtual water has little practical value in decision-making regarding the best allocation of Australia’s scarce water resources.” Similarly, the Netherlands Environmental Assessment Agency (in response to a proposal that the government amend its economic policy to persuade Dutch companies to reduce their water footprints) suggested that “the water footprint indicator is unsuitable to be used for goal-setting, policy-making, monitoring and evaluation, in relation to sustainability.”
- For public awareness, virtual water and water footprints can be good – as tools to communicate with the public about overconsumption and water scarcity, the ideas of virtual water and water footprints have been very effective
- One of the problems with using virtual water as a sustainability indicator or for policy-making…is that purely volumetric measures lack vital context. Consumers half a world away typically don’t know the local socioeconomic and environmental conditions where their food or clothes are produced, limiting their ability to make informed decisions on sustainability
- You have to know: Where does the product come from? Is there water scarcity there? Are there human rights injustices there? Is there pollution there during the growing of the crops? Only if you know all that, she says, can you judge whether a water footprint is good or bad.
- Virtual water and water footprints should ideally be embedded in a broader narrative around water management, productive water use, domestic and international trade
- A high water footprint is not a bad thing per se. A product using a lot of water but originating from a water-abundant region or from a region with sound water management in place does no harm
- In a place like Sri Lanka where rain is abundant in some parts, the water footprint of a coconut probably doesn’t matter too much (because of the amount of rain). People working on coconut plantations or in garment factories depend on local water resources for their livelihoods – which is another reason a higher water footprint doesn’t matter as much
- A big risk with giving too much importance to a simple water footprint, is missing the employment opportunities water provides
- A sustainability index or indicator should capture all the important elements of a problem you are trying to solve. Virtual water and water footprints, which don’t capture all of the necessary elements, have been misused as sustainability indices.
- When talking about water scarcity and water quality, these problems are generated locally, and they need to be solved locally – not so much on a global level. This is the opposite to carbon footprints, which impact both local and global communities
- Water footprints need to target individual countries, states, river basins or even cities — to get a more accurate and relevant picture of virtual water flows and their impacts. Patterns of water use are really driven not by countries, they’re driven by cities
- Virtual water should have to do with what you are using the water for, what value you are creating, in terms of jobs and money, what you are getting for your water use, and how we are dependent on our neighbors at a very small scale. It should also distinguish among green, blue and gray water (because they are not all equal from a financial, cultural and environmental perspective)
- How best to measure gray water and how comparable it is to green and blue water is one reporting area that can be refined. Polluted water/grey water may need to be separated out from the virtual water reporting
- How far upstream through supply and production chains one accounts for in calculations, for instance, will clearly affect the results of virtual water reporting, as will the quality of data available in different areas. However, as long as the scope and goals of virtual water and water footprint assessments are clearly laid out and acknowledged, confusion over such inconsistencies can be mitigated.
- Standardisation of virtual water reporting may help
- Most supporters of the virtual water and water footprint notions acknowledge some weaknesses while continuing to stress their usefulness. Volumetric indices alone are not sufficient to determine the sustainability of water use related to any particular crop, product, company or country, but they are the most essential pieces of info
- Modeling of virtual water trades is an important tool for planners, but it is not a “magic bullet” to solve problems.
- Water footprints and stats on virtual water may be really important for multinational corporations and businesses – to help them understand how much virtual water they are importing and in what river basins their footprints are located, and what the risks are to their supply chains
- A business is going to be more secure and more profitable if you eliminate risky and unsustainable suppliers from your supply chain
- You might want to know if you’re doing business with a supplier whose water footprint and virtual water trade are really creating problems for the local water supply
- A number of major companies — SABMiller, PepsiCo and Nestlé among them — have adopted the approach – producing reports of their own virtual water usage
- SABMiller offered case studies detailing its operations and footprints in water-stressed areas of Peru, South Africa, Tanzania and Ukraine
- Businesses are typically in a better position than governments to identify unsustainable hot spots in supply chains, where water resources are being threatened through overuse or pollution, because they know in detail where their materials and services are originating
- The problem with regulations obliging companies to report and possibly minimize virtual water usage is that “every company is different and every country is different
- The fair solution, is for governments, companies, nongovernmental organizations and researchers to cooperate to recognize and deal with water issues
- Water footprints consider only the volume of water used in production, without considering other inputs or opportunity costs. Water volumes, alone, are not sufficient indicators of the benefits or costs of water use in any setting. The benefits and costs are functions of complex interactions involving physical, economic, and social dimensions that are not contained or reflected in estimates of water footprints.
- Comparing two water footprints across activities, locations, or time is not a helpful exercise if one does not have information regarding water scarcity conditions, the opportunity costs of water, and water’s role in supporting livelihoods in each setting. The water footprint of coffee might be 140 ml per cup, but that estimate provides no insight regarding the opportunity cost of water in the region where the coffee is produced, or the livelihoods earned by persons engaged in coffee production. Coffee produced in a country with abundant water might place no pressure on water supplies. Yet the activity might provide livelihoods to many residents who have few alternative sources of employment. Such aspects of water allocation decisions are not reflected in estimates of water footprints.
According to Wikipedia:
Key shortcomings of virtual water measures are that the concept:
- It 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.
- It 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.
- It 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:
- 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.
- Importing food could pose the risk of further political dependence. The notion of “self sufficiency” has always been the pride of the MENA region.
- 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.
Where Do The Water Footprint, & Virtual Water Concepts Come From?
The water footprint concept, sources and methodology come from the Water Footprint Network (WFN). The concept was created by Dr. Arjen Hoekstra who, along with the others at the WFN, developed the framework and established the international organization as the foremost research network in the discipline.
Tony Allan, a political geographer and Middle East scholar at King’s College London, coined the term “virtual water” in 1993 to help explain why long-predicted “water wars” driven by water and food security had not occurred among the arid nations of the Middle East and North Africa.
Allan noted that Egypt, Israel, Jordan and other countries in the region were buying millions of tons of grain each year from water-rich countries to supplement their own food production and buoy prosperity (countries in the Middle East can save their scarce water resources by relying more on import of food).
What Causes An Increase In, Or Puts Pressure On The Water Footprint?
- As population size increases, so too does water use for everything – products and food included
- Using water intensive food, electricity and consumer goods increases the water footprint
- By the year 2030, experts predict that global demand for water will outstrip supply by 40 percent.
- Impacts from climate change have already led to changes to the water cycle, leading to prolonged periods of drought (and, conversely, more extreme rainfall) in some areas.
- Reduced water supplies could add to water insecurity both in the US and in other countries.
The interest in the water footprint is rooted in the recognition that human impacts on freshwater systems can ultimately be linked to human consumption, and that issues like water shortages and pollution can be better understood and addressed by considering production and supply chains as a whole
Water problems are often closely tied to the structure of the global economy. Many countries have significantly externalised their water footprint, importing water-intensive goods from elsewhere. This puts pressure on the water resources in the exporting regions, where too often mechanisms for wise water governance and conservation are lacking. Not only governments, but also consumers, businesses and civil society communities can play a role in achieving a better management of water resources
Reducing The Water Footprint
- It’s worth looking at how we can both save water and use it more efficiently
- Reducing, reusing and recycling water can save lots of water from the water footprint
- Buying fewer products in the first place reduces the overall number of products that are made, and, in turn, reduces the amount of water needed by the factories that make these products. Additionally, recycling consumer goods can have a positive effect. In 2012, for example, the US threw out over 24 million tons of paper and almost 29 million tons of plastic – both of which are water-intensive materials that can be re-used and/or recycled. Recycling a pound of paper – the same amount found in a typical daily newspaper – saves 3.5 gallons of water.
- Small actions like recycling at home, reusing items when possible and using fewer plastic bags and paper towels can make a small but cumulative difference in water consumption. Reducing the need for new products in the first place – ending overconsumption – is the strategy that saves the most water. Avoiding purchases of disposable, low-quality goods that are made to go in the trash makes a big difference. Buying used items and thrifting – especially for clothing – or buying products that are of higher quality, reusable and, if need be, recyclable, are the best options when new purchases are necessary.
- There is a lot of water usage in energy – The average American today uses about five times more electricity than they did 50 years ago. This increase is significant because it takes a substantial amount of water to create energy. Water is used to cool steam electric power plants – fueled by coal, oil, natural gas and nuclear power – and is required to generate hydropower. Water is also used in great quantities during fuel extraction, refining and production. So, wasted energy is, in effect, wasted water.
- Also, due to increasingly efficient manufacturing practices, most factories have reduced water use by 12 percent since 2005, and 33 percent since 1970.
- In summary – consumers can shop smarter, recycle, save water and save energy.
- Nobody will have a water footprint of zero because it takes water to make just about everything we choose to buy, eat, use and throw away.
As consumer, we can also buy and use or consume products and food that requires less water to make
We can use products that use less water – like washing machines and dishwashers for example
We can reduce food waste
Businesses can reduce water in their production (whether that is growing, rearing, mining etc.) and manufacturing processes, and use it more efficiently
Water Footprints For Food & Products Can Differ By Country
Different countries can have different water footprints for the food they produce, and products they make.
You can read more in:
- And the table at https://en.wikipedia.org/wiki/Virtual_water
Importing Virtual Water, & Virtual Water In Trade Between Countries
- China is one of the biggest importers of virtual water in the world
- China is the world’s top soybean buyer, importing tens of millions of metric tons per year. And behind each ton is more than 2,000 cubic meters of water — either rainfall or irrigation — needed to grow, harvest and prepare soybeans for use. In the case of soybeans and other crops, the majority of this water is lost to the atmosphere through evaporation and transpiration during the plants’ lifetime, and none of it — save the tiny amount still hydrating the final product — actually makes it to China. Yet, to an extent, this virtual water represents an enormous volume of real water that China need not pull from its own shrinking endowment.
- Importing water intensive foods or products can be a replacement for having your own water water
- It can ease stress on the countries’ own limited resources, and they can use those resources on other industries and direct consumption
- 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.
- Water-scarce countries like Palestine discourage the export of oranges (relatively heavy water guzzlers) precisely to prevent large quantities of water being exported to different parts of the world
Virtual Water, & Water Footprint Increasing Over Time
- There’s been studies into how virtual water trade volumes related to different crops had changed over time between 1986 to 2007
- The total virtual water volume associated with global food trade had more than doubled during the 22-year study period, in part reflecting the overall growth of global trade; that “international food trade has led to enhanced savings in global water resources over time” by transferring commodities grown in countries that use water more efficiently — either because of more favorable climates or better technology — to less water-efficient countries; and that virtual water trade patterns had shifted substantially in some respects.
- Virtual water trade within North America quadrupled — likely an outcome, at least partially, of the North American Free Trade Agreement enacted in 1994. Asia, meanwhile, increased its virtual water imports by 170 percent, with China leading the way.
- China trades between it’s provinces, and with the rest of the world
- In 2001, China became the world’s largest virtual water importer, and, by 2007, accounted for 13 percent of the total global trade. Roughly 90 percent of this amount was due to imports of soybeans. China had begun lifting restrictions on soybean imports in 2000, resulting in large influxes, predominantly from Argentina, Brazil and the U.S.
Examples Of Water Footprint In Different Foods & Products
We put together a guide of the water footprints of some different products and foods.
Examples of the different types of water footprints and how they make up the different food and product overall water footprints can also be seen here – http://waterfootprint.org/en/resources/interactive-tools/product-gallery/, and here https://www.earthmagazine.org/article/virtual-water-tracking-unseen-water-goods-and-resources
Some Water Footprint Statistics & Trends
- The water footprint of Chinese consumption is about 1070 cubic metres per year per capita. About 10% of the Chinese water footprint falls outside China.
- Japan with a footprint of 1380 cubic metres per year per capita, has about 77% of its total water footprint outside the borders of the country.
- The water footprint of US citizens is 2840 cubic meter per year per capita. About 20% of this water footprint is external. The largest external water footprint of US consumption lies in the Yangtze River Basin, China.
- The global water footprint of humanity in the period 1996-2005 was 9087 billions of cubic meters per year (74% green, 11% blue, 15% grey). Agricultural production contributes 92% to this total footprint.
- Water scarcity affects over 2.7 billion people for at least one month each year.
- IME claim that water requirements to meet food demand in 2050 could reach between 10-13.5tn cubic metres per year – about triple the current amount used annually by humans.
- The average American’s daily water footprint for all the (non-food) household goods they purchase, use and throw away is 583 gallons.
You can find more stats on water footprints and water use at – https://waterfootprint.org/en/resources/waterstat/
Water Footprint Assessment & Calculation Tools
You can find more tools for assessing and calculating water footprints at – https://waterfootprint.org/en/resources/interactive-tools/
There’s also a Water Footprint Calculator at GRACE – http://www.gracelinks.org/1408/water-footprint-calculator
Otherwise, what you can do with food specifically, is:
- Find out the weight of the food you are eating (e.g. an 8oz beef steak), or count the number of that item of food you are eating (e.g. two eggs)
- Google the amount of water that food takes to produce per unit of weight
- Multiply the weight or number of the food item by the litres per weight or number to get the water footprint