An expert voice on the global water challenge

Dr Ismael Serageldin is director of the Biblioteca Alexandrina and former Vice-President of the World Bank, the Founding Chair of the Global Water Partnership, a founding governor of the World Water Council, and the chairman of the World Commission for Water in the 21st Century. He maintains that water management is becoming increasingly critical.

Fresh water is a precious resource. Only 2.5% of the world’s water is not salty, and of that two-thirds are locked up in the ice caps and glaciers. Two-thirds are then “lost” to water that evaporates directly or passes through plants. Of the remaining amount, some 20% is in areas too remote for human access, and 75% of it comes at the wrong time and place, by way of monsoons and floods. We use less than 0.1% of the total water on the planet.

Agriculture claims the largest share, some one-third globally and over 80% in many developing countries. A small amount is used for municipal water use, for households and industry. Water is also very useful in taking away human pollution, but in the process becomes polluted itself.

The World Water Commission affirmed a set of principles to reverse the patent waste and mismanagement of water. Among others, these "Dublin Principles" recognise the economic value of water, observing “the polluter pays and user pays”, and the need for governments to assume their responsibilities. The question is whether these good prescriptions would be sufficient to meet rising consumption needs driven by population and income growth.

Assume 3 billion more people on the planet, mostly in the developing countries. Note that currently it takes on average a litre of water to produce a calorie of food. The average human being therefore requires some 2’700 litres of water per day through food. It takes 2’000-5’000 tons of water to produce a ton of rice, and about 1’200 tons of water to produce a ton of wheat.

Assume further that the contribution of water to all food production is 40%. Assume further that all irrigation systems achieve water use efficiency of 70% at the basin level, a remarkable achievement if it were to happen. Approximately 17% more water is still required in irrigation to meet the food production demand! Altering any of those assumptions means that the forecast for water needs will increase by about 50% or more. However, irrigation is not likely to get more water. The urban populations of the developing world are going to treble in the next 30 years. Industry is going to increase, and pollution is not going to decrease.

What can be done?