Water is an essential resource, but the scale of global water consumption needed to produce what we use and consume has a dramatic impact around the world.

Food and products consumed within a country such as the UK are often produced in other countries. The actual water demand of these nations are often much higher than traditional assessments suggest.

In regions across the world from China to North America; Australia to vast regions of Africa, water resources are struggling to meet demands.

The United Nations Educational Scientific and Cultural Organization (UNESCO) note that for the last century water use has been growing at more than twice the rate as population. The irrigation of agriculture continues to be the largest user of water, making up 80% of water use in developing countries.

At the same time the demands of industry and urban areas are growing rapidly. In 2007 a UN report stated that for the first time in history more people now live in cities than rural areas.

Virtual/Embedded water

The term ‘Virtual Water’ (also known as embedded water) refers to the amount of water that is embedded in food and other products such as clothing and electrical goods.

The production of the food we eat, the clothes we wear and the goods we consume require vast amounts of water for irrigation, processing and packaging.

For example, to produce one kilogram of wheat about 1,000 litres of water is required, i.e. the virtual water of a kilogram of wheat is 1,000 litres. For meat about five to ten times more is required.

The concept of virtual water was introduced by Professor Tony Allen in the early 1990s, while studying the option of importing virtual water (mainly through food imports) as a partial solution to problems of water scarcity in the Middle East.

Hidden water cost of trade

Globalisation has resulted in the integration of many nations into the international global economy through increased levels of trade. As a result many of the goods consumed within countries such as the UK are now produced in other countries across the world.

There are clear and recognised benefits to increasing levels of global trade. But developing countries that increasingly cater for the consumer lifestyles of developed countries are facing serious environmental consequences on local and regional environments.

At the global level, virtual water trade has geo-political implications: it leads to dependencies between countries and can therefore be regarded either as a stimulant for co-operation and peace or a reason for potential conflict.

The water intensive process of growing and processing food, as well as other goods is often carried out in drier areas of the world. In these countries water resources are often either stressed or very likely to become so in the future.
What is a water footprint?

In 2002 the water footprint concept was introduced. It is defined as the volume of freshwater needed for the production of the goods and services consumed by the population of a country. It can also be expressed as an individual’s water consumption.

Traditionally water use has been calculated adding the withdrawals of domestic, agricultural and industrial sectors of a country. This however does not give a true indication of the water actually needed by the population to cater for their lifestyles, as virtual water was never considered until recently.

The true water demand of countries that have high import levels of goods is far higher than national water withdrawals suggest. In the case of the UK, about 62% of the total national water footprint is accounted for by water from other nations, whereas only 38% is used from domestic water resources.

This trend can also work in reverse, with countries that export large amounts of products for consumption elsewhere, such as Australia and Egypt, often have deceptively high national water withdrawals.

Source: World trade Organisation, WTO (2003): International trade statistics 2003

Virtual water trade is not new; it is as old as there is food trade. However, the amount of world trade has been steadily increasing since the 1950s.

Import of virtual water can help to relieve the pressure on a nation’s own water resources and environment. Countries, especially those that are water abundant, can export virtual water, however this can lead to environmental consequences and lead to the overexploitation of local resources.

In the past governments have responded to water stress by seeking to augment supply. In the period 1960-2000, the Aral Sea lost approximately 60% of its area and 80% of its volume as a result of the annual abstractions of water from the Amu Darya and the Syr Darya – the rivers which feed the Aral Sea – to grow cotton in the desert. Large scale river diversion programmes in China and India show its continuing use.

With the trade of food crops or any commodity, there is a virtual flow of water from producing and exporting countries to countries that consume and import those commodities. In richer countries, people generally consume more goods and services, which in turn translate into increased water footprints both internally and imported from external countries.

Consumption patterns between countries, closely aligned to the gross national income of a country, vary greatly between countries in different regions of the world.

Water-scarce countries can import products that require a lot of water for their production rather than producing them domestically. By doing so, it allows real water savings, relieving the pressure on their water resources or making water available for other purposes.

A recent study carried out by WWF shows that the UK is currently the 6th largest net importer of virtual water for agriculture, behind Brazil, Mexico, Japan, China and Italy.

The irrigation, processing and packaging of the produce that the UK consumes includes water intensive goods such as meat, soya, oil seed, rice, coffee and cocoa. These imports are sourced from Brazil, France, Ireland, Ghana and India among others.