The central question in this chapter is: can the world population be provided with an adequate and sustainable supply of clean water? We report on experiments with the AQUA submodel and attempt to offer insight into the role of population and economic growth, intensive agriculture, technology and pricing. Again three cultural perspectives are applied to establish model routes which reflect different assumptions and societal responses. The model experiments provide a number of water projections for the next century. We review low, medium and high risk developments and the effects of various water policy strategies. The chapter concludes with a proposal for future policy priorities to safeguard a sustainable supply of clean fresh water.

Introduction

There are too many uncertainties to give a simple answer to the question whether we will have enough clean water for the next century. However, we can do some exploratory work if we make certain assumptions. In this chapter, we present such an exploration based on the AQUA submodel (Chapter 6). As a heuristic device for composing coherent sets of assumptions, different perspectives are used (see Chapter 10). First, we discuss some of the major questions, uncertainties and controversies related to water and sustainable development. We then look for coherence in the different points of view by considering the controversies from three perspectives: the hierarchist, the egalitarian and the individualist. Next, we use the three perspectives to implement ‘model routes’ within the AQUA submodel and to present model–based projections of water in the next century. Finally, we distinguish low, moderate and high risk futures, and analyse the effects of different water policy strategies. More detailed background information can be found in Hoekstra (1997).