The Unseen Water in Agriculture

Chinmoy Kr. Sarma

We drink, clean, and cook with water each day, but our greatest “water footprint” is hidden in the goods we buy-food, paper, clothing, and the like.

We often forget the huge amount of water it takes to produce these everyday products. When we take a cup of coffee, we are drinking not just the liquid in the mug but also the hundreds of litres of water required for growing and processing the beans.

Similarly, when one country ships wheat to another,it is effectively “exporting” the thousands of litres of water it takes to grow that grain. The term ‘virtual water’ is most usefully applied to water that is taken directly into a product in the course of its production or manufacture. It accounts for the direct water used in the production of a product as well as the indirect water used atdifferent stages of its supply chain.

For example, a cotton t-shirt has a large virtual water footprint because of the water which is used to grow a cotton crop, make the fabric and move the finished product. In the case of a food crop, the virtual water content is the total amount of water (rainfall and irrigation) used by the crop during its growth through evapotranspiration.

This is commonly referred to as “water footprint” or “embedded water”, which measures the specific amount of water used to produce a food commodity.This concept was originally developed to understand how countries with scarce water resources could meet the demand for food, clothing and other water-intensive goods for their populations. John Anthony Allan (Tony Allan) coined the term ‘virtual water’ in 1993, and for this idea, he was awarded the Stockholm Water Prize in 2008.

The concept of virtual water can help us understand how our consumption habits affect water resources. It can also help us to identify ways to reduce our water footprint. The effect of virtual water consumption in our diet depends largely on what we eat.

For example, producing animal-based products requires significantly more water than producing plant-based foods, in part because of the water needed to grow their feed. The estimated water footprint is 4300 litres per kg chicken, 5000 litres per kg cheese, 1600 litres per kg wheat, 300 litres per kg vegetables, 135 litres per egg, 1000 litres per kg milk and 800 litres per kg fruit, as per FAO data. So cutting down on meat in your diet can make a big difference in water footprint.

But the real impacts depend on the timing and location of water extraction. If higher water footprint is in a water-rich area, it might not be much of an issue, but in areas with little water, it could lead to dried rivers, habitat destruction, species extinction and damaged local economies.

India has about 18 per cent of the world’s people but less than 4 per cent of its freshwater. Many areas already have chronic water shortages, taking the country from beingwater-stressed to a water scarcity.Large agricultural exports like rice have a huge “water footprint” which depletes domestic reserves and threatens long-term water security, creatingthe sustainability crisis as a major net exporter and one of the world’s largest virtual water consumers.

Countries with water scarcity can reduce the pressure on their own water resources by importing water-intensive products with the help of a practice referred to as “virtual water trade”. It involves the transfer of virtual water between different areas through the exchange of physical goods such as foodstuffs that have needed water for their production.

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By importing goods from areas where water is abundant, water-scarce countries can effectively ‘import’ water in a virtual sense and thus can reduce their own consumption of water. This is especially applicable in case of water-intensive products such as meat, cotton or crops like rice and wheat.

If a country imports one tonne of wheat rather than producing it at home, it saves approximately 1,300 cubic metres of real indigenous water.Water-scarce nations like Israel prohibit the exportation of oranges in order to avoid the export of huge amounts of water to various corners of the globe

.The virtual water export of India in the form of water-intensive crops such as rice, sugar, and cotton actually works as a very big virtual water export and adds to the water crisis in the country. The theoretical benefit of virtual water trade is that the nations abundant in water resources must export products that consume large amounts of water.

Similarly, the arid nations must import such products. However, this rule applies even to the largest nations on earth, such as the United States. On the contrary, the reality is that even nations facing severe water scarcity and climatic change, such as Pakistan and Syria, continue to be one of the largest exporters of water-intensive products.

It is because rich nations can afford to import more water virtually that scarcity may increase in poor nations that export products. Besides, the world market does not consider the environmental costs of water usage in the product production process.

Consequently, while virtual water trade can be a solution, careful management is essential to ensure that global water resources are used fairly and sustainably.

Dr. Chinmoy Kumar Sarma, Chief Scientist, Irrigation Water Management, Assam, Agricultural University, Jorhat ; Mobile: 9957130225

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