Water: the looming problem
- Water: the looming problem
World Water Day is held annually on March 22 to focus attention on the importance of freshwater and advocate sustainable management of freshwater resources. Each year, the day highlights a specific aspect of freshwater and this year's campaign was on "Water and Food Security." A large quantity of water, more than most people think, is used for producing the food we eat everyday. Water is a renewable and finite resource available globally to the tune of 200,000 km. The human population, on the other hand, has been continuously growing, which means that there is less water for everyone to satisfy the need for living a healthy life.
The steadily increasing demand for agricultural products is the main reason behind agricultural water use. Besides, economic development, particularly in emerging market economies, is translating into a demand for a more varied, water-intensive diet, including meat and dairy products. Agriculture accounts for 70% of freshwater withdrawals from rivers, lakes and aquifers more than 90% in some developing countries. Rainfed agriculture covers 80% of the world's cultivated land and is responsible for about 60% of crop production.
In rainfed agriculture, the soil stores rainwater and releases it slowly to the plants, and hence is not usually subject to competition from other sectors. But in irrigation, water is extracted from rivers, lakes and aquifers and applied to land. Thus, irrigation often competes with other water user sectors domestic, industrial, energy, fisheries and environment.
The last 50 years have witnessed a rapid acceleration in water resources development for agriculture. Development in hydraulic infrastructure (dams and large-scale surface irrigation) as well as private and community schemes (particularly groundwater pumping) have put water at the service of populations as part of the global effort to rapidly increase staple food production, ensure food self-sufficiency and avoid famines. As the global population grew from 2.5 billion in 1950 to six billion in 2000, the irrigated area doubled (particularly in Asia), and water withdrawals tripled. As population continues to grow (the projected growth in 2050 is nine billion), the demand for food intensifies, and the pressure on water from agricultural activities is expected to increase. Agriculture is also facing competition for water from the domestic and industrial sectors, and its allocation is decreasing in water-scarce areas, especially around urban centres.
The issues in agricultural production are further complicated by increasing climate uncertainty. Large areas of croplands, particularly in semi-arid zones, will need to adapt themselves to new conditions with lower precipitation. Studies show that the future for agriculture-based economies is most vulnerable with respect to the anticipated climate change effects.
In brief, there are seven billion people to feed on the planet today and another two billion are expected to join by 2050. When a billion people in the world already live in chronic hunger, water resources allocation gets much more complicated. However, water (which determines life and livelihoods) is a free gift of nature and renewable resource. We cannot manufacture water according to its demand or find out a substitute. Coping with population growth and non-agricultural water requirements (drinking and other domestic use, industry and environment) and ensuring access to nutritious food for all are a challenge.
In this regard the following pre-requisites are suggested:
Consume less water-intensive food products to the maximum extent possible.
Reduce atrocious food wastage: Around 30% of the food produced worldwide is never eaten, and the water used to produce it is a loss.
Produce more food with less water: Water productivity should be improved with the application of less water-intensive technologies, like sprinkler and drip irrigations. Further, proper land preparation (ploughing) and implementation of biofertilizers will reduce water requirements considerably.
For each crop, the optimum water requirement should be identified and irrigation designed accordingly.
Research should be encouraged for innovation of less water-intensive and high-yielding seeds for different crops.
The application of `marginal/second quality of water' in agriculture should be encouraged, especially in water scarce areas. In this regard, treated domestic and industrial waste water has great scope. However, the safety (quality) of food items manufactured through effluent irrigation, and the health of the labourers who are working on the field, have to be guaranteed.
Water saving through trade!
The water used to produce agricultural or other products is called the virtual water of the product. Through trade, a substantial volume of water is being transferred from one region to another, and this phenomenon is known as the "virtual water trade." The global volume of virtual water flows related to the international trade in commodities is 1,600 km/year, and about 80% of it is through trade in agricultural products, while the remainder is related to industrial products. Globally, water is saved if agricultural products are traded from regions with high water productivity to those with low water productivity. At present, if importing countries produced all imported agricultural products domestically, they would require 1,600 Km of water a year. However, the products are being produced with only 1,200 km/year in the exporting countries. Therefore, we are saving 400 billion m of global water resources annually!
The statistical references mentioned in this article are taken from various reports published by the Food and Agriculture Organisation, and the United Nations (World Water Development Report).
(The writer belongs to the Centre for Water Resources, Anna University, Chennai. His email is nelliyatp@...)