Special issue on Discounting the Long-Run Future and Sustainable Development Editor’s Introduction

The major aim of this special issue is to demonstrate that in the eighteen years since that comment in The Economist, the nature of the problem with long-run discounting and its compatibility with the concept of ‘sustainable develeopment’, as used by the Brundtland Commission, has become clearer. The practice of discounting the future has long been controversial both within the economics profession, and in the philosophical critiques of welfare economics and its counterpart, cost-benefit analysis.3 Discounting involves lowering the weight given to a unit of cost or benefit in the future compared with the present. The further into the future the costs and benefits occur, the lower the weight tends to be. The higher the discount rate, and hence the lower the weight, the less likely it is that investments or policies that incur short-run costs and long-run benefits will be sanctioned by costbenefit analysis. Conversely, projects with short-run benefits and long-run costs are more likely to be sanctioned by cost-benefit analysis. The resulting ‘tyranny of the