An important call to protect the world’s freshwater supplies has come from scientists, government leaders, and civil society representatives who met recently in Stockholm for World Water Week. As population and incomes grow, with concomitant consumption, there is a sharp rise in the demand for water for direct use, and as an input for food production. Many countries are also experiencing rising demand for water to grow biofuel crops. The global supply of freshwater, which every individual needs at the rate of 1,000 cubic metres per year to meet minimum drinking, hygiene, and subsistence requirements, is under strain. Unpredictable monsoon patterns attributed to climate change are adding to the distress. The message to governments is that they must respond urgently with practical schemes or face escalating conflicts over water in the not-so-distant future. The priority must be to reduce water intensity in farming, the biggest single user. Even a small but significant saving in irrigated agriculture can deliver more water for people. That is clear from an International Water Management Institute forecast: without improved farm productivity, including measures such as waterproofing of canal surfaces, the volume of water lost due to evaporation annually could, by mid-century, be nearly double the present level of 7,130 cubic kilometres.
Conservation of water requires consumers to act wisely. Food contains a great deal of embedded water (a kilo of wheat needs 1,000 litres to produce, according to data presented at the Stockholm conference) and discarding it as garbage wastes the precious resource. The conference heard distressing evidence of a large amount of food being thrown away every year, mainly in the developed world. According to a policy brief released at the conference, in the United States, as much as 30 per cent of the food produced, valued at $48.3 billion, is thrown away; that wastes an estimated 40 trillion litres of water, enough to meet the needs of 500 million people. In developing countries, a lot of produce perishes right on the farm, in storage, and during transport. Cumulatively, this represents a colossal burden of waste. The challenge before all countries is to translate the improved awareness into effective conservation policies. Some may choose to charge for excessive water use and also deploy technologies such as desalination to increase availability. But these represent the low-hanging fruit. A sustainable future will depend on creating strong watersheds for farming, forming community tanks and lakes for rainwater harvesting, and strictly enforcing rules that compel cities and towns to reuse grey water.
6 months ago