استدلال در برابر یک رویکرد تقلیل گرایانه برای اندازه گیری عملکرد توسعه پایدار و نیاز به کثرت گرایی روش شناختی

Both sustainability and sustainable development continue to remain elusive concepts even now, 20 years after the Brundtland Commission report that brought them into prominence. This situation most likely stems from the fact that sustainability science encompasses the need to address a wide set of issues over different time and spatial scales and thus inevitably accommodates opinions from diverse branches of knowledge and expertise. However, despite this multitude of perspectives, progress towards sustainability is usually assessed through the development and utilisation of single sustainability metrics such as monetary tools, composite sustainability indices and biophysical metrics including emergy, exergy and the ecological footprint. But is it really justifiable to assess the progress towards sustainability by using single metrics? This paper argues that such a choice seems increasingly unjustifiable not least due to these metrics’ methodological imperfections and limits. Additionally, our recent awareness of economies, societies and ecosystems as complex adaptive systems that cannot be fully captured through a single perspective further adds to the argument. Failure to describe these systems in a holistic manner through the synthesis of their different non-reducible and perfectly legitimate perspectives amounts to reductionism. An implication of the above is the fact that not a single sustainability metric at the moment can claim to comprehensively assess sustainability. In the light of these findings this paper proposes that the further elaboration and refinement of current metrics is unlikely to produce a framework for assessing the progress towards sustainability with a single metric. Adoption of a diverse set of metrics seems more likely to be the key for more robust sustainability assessments. This methodological pluralism coupled with stakeholder involvement seems to offer a better chance of improving the outcome of the decision making process.

Governmental bodies, non-governmental organisations, academics and the public are engaged worldwide in policy discussions trying to envision and operationalise a development path that can meet the needs of present and future generations in an equitable manner. The goal of increasing the economic welfare of a population over time is not a new policy objective. However, the acceptance during the past two decades that the state of the environment and the functioning of society are equally as important has led to the formulation of more elaborate policy questions. The desired development path that ensures the economic welfare of present and future generations by further considering environmental and social issues has come to be known as sustainable development and was brought into prominence by the Brundtland Commission (WCED, 1987). Even though there is no universally accepted clear cut definition for the term there is a consensus that economic, environmental and social issues together with intra- and inter-generational equity ought to be considered within the framework of sustainable development (Gibson, Hassan, Holtz, Tansey, & Whitelaw, 2005). Furthermore, the importance of considering the significant uncertainties associated with the design of strategies and particularly of those strategies that will span well into the future has been widely acknowledged by academics and policy makers. Incomplete knowledge in social and natural sciences coupled with evolving human preferences and values make a case for acting with a precautionary bias by implementing the precautionary principle (Gibson et al., 2005). Another key element is the involvement of stakeholders, especially those directly affected by a plan/policy/programme, in the planning and decision making process (Meppem, 2000; Meppem & Gill, 1998). Not surprisingly, measuring sustainable development performance and quantifying the progress towards sustainability is currently at the centre of an ongoing debate that has strong policy implications and is thus progressively moving beyond the academia. Tools and methodologies based on the reductionist paradigm have been used over the past years to measure the progress towards sustainability but very few of them seem to be able at the moment to assess sustainability in a holistic manner (Gasparatos, El-Haram, & Horner, 2008). Tools and descriptive models falling within this reductionist paradigm, according to Munda (2006), make use of a single: • measurable indicator (e.g. GDP per capita); • dimension (i.e. one of the economic, environmental or social dimension); • scale of analysis; • objective (e.g. maximisation of economic efficiency); • time horizon. The majority of such reductionist sustainability assessment methodologies seem to fall within three major categories: monetary tools, biophysical models and sustainability indicators/composite indices (CIs). The advantage of such tools lies in the fact that they can reduce and integrate the diverse issues affecting the progress towards sustainability to a small set of numbers. Such tools can be invaluable to policy makers as they can be used to understand various natural and human systems and summarise a large volume of information to non-experts thus simplifying the decision making process. Understanding a system by simplifying it and offering aggregated information for decision making are in our view the two most critical functions of the reductionist tools that will be discussed. As a result, relevant insights from two new scientific paradigms, complexity theory and post-normal science, will be discussed in Section 2 of our study in order for the reader to appreciate the context within which sustainability assessments are made. Monetary tools, based on the neoclassical paradigm, have formed the backbone of most sustainability assessment exercises especially for policy making during the past years. However, the most commonly used monetary tools were not conceived specifically for assessing the progress towards sustainability but were rather developed and have matured before the sustainable development debate erupted. Examples include evaluation tools such as market valuation, Contingent Valuation Method (CVM), Hedonic Pricing, Travel Cost Method and aggregation tools such as Cost Benefit Analysis (CBA). The adaptation of extant monetary tools to assess the progress towards sustainability had the great advantage of building from strong theoretical foundations in neoclassical economic theory which has been the dominant paradigm of Economics from the beginning of the 20th Century. However, it soon became obvious that such tools are inadequate in certain situations given that positive progress towards sustainability goes beyond economic efficiency to include equity considerations. Another concern arose through the monetisation of certain environmental and social issues with several criticisms targeting the methodological, conceptual and philosophical aspects of the monetisation procedures adopted. Such criticisms made the case for developing models with solid foundations in the natural sciences that can quantify resource consumption and subsequent environmental impacts more reasonably (Ecological Economics, 1999; Munasighe & Shearer, 1995). Biophysical models based on a reductionist perspective attempt to elucidate the metabolism of different systems (e.g. production/consumption patterns) by making use of common denominators other than money such as available energy (emergy synthesis and exergy analysis) and land (ecological footprint). Changes of these flows over time offer insights into whether there has been a positive or negative progress towards sustainability (e.g. decreasing the ecological footprint of a system over time implies a positive progress towards sustainability as it will be discussed in more depth in Section 3.2). Currently there seems to be an active interest in sustainability indicators judging from the large number of sustainability indicator lists published by academics, local authorities, national and international organisations (Esty, Levy, Srebotnjak, & de Sherbinin, 2005; Prescott-Allen, 2001 and UN, 2001). These indicator lists usually comprise a series of indicators that capture sustainability issues relevant to the context of the specific assessment exercise. As a result, in most cases, specific indicators lists are not as generally applicable as monetary and biophysical sustainability assessment tools. Indicators in such list are sometimes aggregated to a single composite index in order to reduce the diversity of sustainability issues to a single number. Aggregation choices are usually a trade off between loss of information when aggregated and fuzziness when not aggregated. Accountants are increasingly required to wrestle with issues of measuring sustainability performance. But sustainable development as an interdisciplinary field of inquiry incorporates insights from a plethora of academic disciplines including the natural, engineering and social sciences. As a result a number of different sustainability assessment tools that have been developed to measure sustainability performance have been published over the past years. Sustainability assessment tools, such as the ones mentioned above, must be accurate, robust and based on sound theoretical foundations backed with empirical evidence if misleading policy messages are to be avoided. With these prerequisites in mind, this article attempts to shed further light on whether it is possible to capture the progress towards sustainability with a single reductionist metric. In particular, this paper exposes some of the strengths and weaknesses of certain tools that follow the reductionist paradigm and have gained some acceptance predominantly between the academic and secondarily between the policy making communities. Key methodological, ethical and philosophical limitations are discussed in greater depth allowing the reader to appreciate their potential for measuring sustainable development performance. In the authors’ views, methodological limitations are non-controversial and thus can offer a relatively clear picture of these tools’ shortcomings when dealing with sustainable development questions. Philosophical and ethical questions, on the other hand, are much more difficult to be substantiated, and the authors have refrained from exploring them in depth. Nevertheless certain key ethical and philosophical limitations have been discussed in more depth including the monetisation of certain environmental and social issues, the substitution between different sustainability issues and finally how the different concepts of value employed by monetary and biophysical tools affect sustainability assessments. In our view, employing a variety of reductionist metrics is preferable when holistic sustainability assessments are required because this multiplicity of tools can offer a better view of the overall situation. In this respect this study will build on the work of Gasparatos et al. (2008) and comment on certain philosophical and methodological assumptions of different reductionist sustainability assessment tools that seem incompatible with sustainable development pre-requisites. Our study, further attempts to make stronger the case for methodological pluralism in sustainability assessments as we argue that methodological pluralism with all its strengths and weaknesses should be invoked when holistic sustainability assessments are needed and reductionist metrics are employed.

Assessing the progress towards sustainability requires the consideration of a plethora of economic, environmental and social issues and equity. At the moment none of the current popular methodological proposals seems, that fall within the reductionist paradigm, to be able to encompass all these considerations simultaneously. Methodological limitations, different concepts of value and new insights from complexity theory and post-normal science leave little room for believing the contrary. The existence of a value system is a prerequisite of any approach for measuring the progress towards sustainability. However, the difficulty in either finding an absolute measure of value or obtaining consensus about which value system to use creates a controversy which so far has eluded resolution. In answering the question posed earlier we believe that assessing the progress towards sustainability with a single metric in a holistic manner is a very difficult task that seems impossible at the moment and attempting to do so is likely to send misleading policy messages. As a result methodological pluralism coupled with stakeholder participation seems a safer path to tread.