WATER | To produce food worth 3,000 calories for each of the world’s 7 billion people, our daily requirement of water is equivalent to a water body that is 1 m deep, 1 km wide, and 7 million km long, enough to go around the earth 194 times. At this rate, 1.8 billion people will be living in absolute water scarcity and two-thirds of the world’s population will face water stress by 2025
Tehelka, 3 June, 2013
Tehelka, 3 June, 2013
IT TAKES a lot of water to produce food. Processing before consumption requires even more. If our diet is 80 percent plant and 20 percent animal products, the waterneeded to produce that quantity of food will be around 1,300 m3 or half an Olympic-size swimming pool per person per year.
Neither our history of water use nor the future projection offers any solace. While the world’s population increased by 300 percent in the 20th century, the use of water increased by a staggering 700 percent. By 2050, we will need 10-13.5 trillion m3 of water per year — about three times the present volume — to meet our food demand.
About 40 percent of the world’s food supply now comes from irrigated land. But water used in irrigation is often sourced unsustainably, through boreholes sunk into poorly managed aquifers. In some cases, energy subsidies by governments drive and exacerbate this problem.
Moreover, we continue to follow wasteful irrigation methods, such as flood or overhead spray, which are difficult to control and lose much of the water to evaporation and run-off. Rampant soil and water salinity has been reported in large irrigation schemes in Pakistan, China, India, Argentina, Sudan and many countries in Central Asia, where more than 16 million hectares of irrigated land is now salinated. Although drip or trickle irrigation methods are more expensive to install, they can save as much as 33 percent water and also carry fertilisers directly to the roots.
A major shift in our eating habits towards meat also puts significant pressure on water. Beef, for example, needs about 50 times more water than vegetables per unit. While food derived from crops consumes less water than if derived from animals, plants also have their hierarchy of water efficiency.
Potatoes, groundnuts and onions, for instance, require little water but choice of water-intensive crops such as sugarcane or rice in arid regions for higher profit results in unnatural water demand and drains aquifers. Greed, therefore, was the single reason for north India recording the world’s highest extraction of groundwater, according to a 2009 study by Hyderabad’s National Geophysical Research Institute and the University of Colorado, US.
Between August 2002 and October 2008, groundwater depletion in Rajasthan, Punjab, Haryana and Delhi was equivalent to a net loss of 109 cu km of water — double the capacity of India’s largest surface water reservoir. By 2050, the groundwater level in most of our river basins, including the Ganga, Krishna, Cauvery and Godavari, will fall by at least 50 percent.
TEHELKA reports from one of the most backward districts in Andhra’s Telangana region about how agroprocessing industries are mindlessly being promoted in a water-deficient region. On the other hand, we explore an oasis of a village in a chronic drought-prone part of Maharashtra that is earning 22 times more from agriculture after implementing low-cost watershed management.
Click to read: Medak gets that sinking feeling | Harvest rain, grow grapes in drought
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