Sustainable development planning: allowing for future generations, time and uncertainty

The view that sustainable economic development is desirable has become widely accepted in recent decades. Sustainable development is generally recognized as the type of economic development that lasts. However, in practice this is an imprecise development goal. It fails to distinguish adequately between the desirability of the different economic development paths that are possible and to assess the economic sacrifice that current generations should make to benefit future generations. Furthermore, one needs to consider the willingness of current generations to make such sacrifices (if they are required to do this) to benefit future generations and how many future generations should be (or are) taken into account in adopting policies to achieve sustainable development. This has implications for the time-period for which it is rational to develop plans and policies to achieve sustainable development. Taking into account these challenges, this chapter discusses the concept of sustainable economic development based primarily on Rawls' principle of justice (Rawls, 1971), and then presents an alternative criterion for determining a desirable path of economic development. Then the practice in economics of discounting the predicted utilities (levels of well-being) of future generations is examined. Is, for example, this an appropriate method of allowing for the limited concern of current generations for the welfare of more distant generations? Will lowering this discount rate increase the likelihood of more sustainable or desirable development paths being chosen? Subsequently, the implications of the limited concern of present generations for distant generations and of uncertainty for development planning are discussed. How does and how should this affect the planning horizon? What implications should it have for the nature of plans and their detail