Ensuring Water Security Under Climate Change

Abstract

Water security and climate change are only two of the major long-term problems the world is facing at present. Increasing population, urbanisation and demands for a better quality of life all over the world mean more food, energy and other resources will be necessary in the future. Increasing food and energy supplies will require more efficient water management all over the production and supply chains. All these requirements have to be met in a way so that significantly less greenhouse gases are emitted into the atmosphere which are contributing to climate change at an increasing scale. Historically, the total global water demands have steadily increased. Currently, about 70% of global water is used by agriculture, 20% by industry and 10% by domestic. In all these three use areas, there is enough knowledge available to reduce water requirements very significantly. Agricultural production can be very substantially increased with much lower water requirements. Domestic and industrial wastewaters can be collected, treated and reused. With proper management, this virtuous cycle can be a reality. While conceptually global water security can be assured by using current knowledge, climate change considerations have made ensuring global water security a very complex task. This is because major uncertainties are associated with any forecast of future extreme rainfalls and then translating them into runoffs in river basins and sub-basins which often are units of planning. This chapter reviews and assesses what can be done to ensure water security for individual countries as well as the world as a whole. Thereafter, it analyses the risks and uncertainties that policymakers and water professionals are likely to face in dealing with climate change through the lens of water security.