Sustainability 2010, 2, 3436-3448; doi:10.3390/su2113436 sustainability ISSN 2071-1050 www.mdpi.com/journal/sustainability Review What is Sustainability? Tom Kuhlman 1,* and John Farrington 2 1 Agricultural Economics Research Institute, Wageningen University, P.O. Box 29703, 2502LS The Hague, The Netherlands 2 Institute for Rural Research, Geography and Environment, University of Aberdeen, Elphinstone Road, Aberdeen AB24 3UF, Scotland, UK; E-Mail: [email protected] * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +31-70-3358-232; Fax: +31-70-3615-624. Received: 17 September 2010; in revised form: 15 October 2010 / Accepted: 19 October 2010 / Published: 1 November 2010 Abstract: Sustainability as a policy concept has its origin in the Brundtland Report of 1987. That document was concerned with the tension between the aspirations of mankind towards a better life on the one hand and the limitations imposed by nature on the other hand. In the course of time, the concept has been re-interpreted as encompassing three dimensions, namely social, economic and environmental. The paper argues that this change in meaning (a) obscures the real contradiction between the aims of welfare for all and environmental conservation; (b) risks diminishing the importance of the environmental dimension; and (c) separates social from economic aspects, which in reality are one and the same. It is proposed instead to return to the original meaning, where sustainability is concerned with the well-being of future generations and in particular with irreplaceable natural resources—as opposed to the gratification of present needs which we call well-being. A balance needs to be found between those two, but not by pretending they are three sides of the same coin. Although we use up natural resources at the expense of future generations, we also generate capital (including knowledge) which raises future well-being. A major question is to what extent the one compensates for the other. This debate centres around the problem of substitutability, which has been cast into a distinction between ‘weak’ and ‘strong’ sustainability. It is argued that these two do not need to be in opposition but complement one another. OPEN ACCESSSustainability 2010, 2 3437Keywords: sustainability; well-being; welfare 1. Introduction The term sustainability has become popular in policy-oriented research as an expression of what public policies ought to achieve. The principal inspiration came from the Brundtland Report of 1987 [1]. Since then the concept has shifted in meaning. This paper argues that the shift is unfortunate in that it obscures the real contradiction which exists between long-term sustainability and short-term welfare. Moreover, the distinction between three ‘pillars’of sustainability is conceptually fuzzy. We propose a definition that reverts to the original sense in which the concept was intended. However, this paper does not pretend to offer a comprehensive view of the problem of sustainability. It presents a critical view of how the term is used in policy debate and in impact assessment—the set of methods used in applied research to appraise policies and projects. 2. History of the Concept The concept of sustainability was originally coined in forestry, where it means never harvesting more than what the forest yields in new growth [2]. The word Nachhaltigkeit (the German term for sustainability) was first used with this meaning in 1713 [3]. The concern with preserving natural resources for the future is perennial, of course: undoubtedly our Palaeolithic ancestors worried about their prey becoming extinct, and early farmers must have been apprehensive about maintaining soil fertility. Traditional beliefs enjoined thinking in terms of stewardship and concern for future generations, as expressed in the oft-quoted words of a Nigerian tribal chief who saw the community as consisting of “many dead, few living and countless others unborn” [4,5]. Perhaps there have always been two opposing views of the relation between humankind and nature: one which stresses adaptation and harmony, and another which sees nature as something to be conquered. While this latter view may have been rather dominant in Western civilization at least in recent centuries, its counterpoint has never been absent. Sustainability (without necessarily using the word) is a natural topic of study for economists: after all, the scarcity of resources is of central concern to the dismal science. A famous example is the work of Thomas Malthus, who published his theory about looming mass starvation (due to the inability of available agricultural land to feed an expanding population) in 1798. A theory on the optimal rate of exploitation of non-renewable resource which is still relevant today was formulated by Harold Hotelling, an American economist, in 1931 [6]. We shall have more to say about his views later. A milestone in capturing the attention of global public policy was the report of the Club of Rome [7], which predicted that many natural resources crucial to our survival would be exhausted within one or two generations. Such pessimism is unbecoming in public policy which is, after all, supposed to be about improving things. Therefore, the report of the UN World Commission on Environment and Development, better known as the Brundtland Report after its chairperson, was welcomed for showing a way out of impending doom. It was this report which adopted the concept of sustainability and gave it the widespread recognition it enjoys today.Sustainability 2010, 2 3438The question which Brundtland and her colleagues posed themselves was: how can the aspirations of the world’s nations for a better life be reconciled with limited natural resources and the dangers of environmental degradation? Their answer is sustainable development, in the Commission’s words: development that meets the needs of the present without compromising the ability of future generations to meet their own needs [1]. Thus, environmental concerns are