No abstract

Sustainability assessment is a recent framing of impact assessment that places emphasis on delivering positive net sustainability gains now and into the future. It can be directed to any type of decision-making, can take many forms and is fundamentally pluralistic. Drawing mainly on theoretical papers along with the few case study examples published to date (from England, Western Australia, South Africa and Canada), this paper outlines what might be considered state-ofthe-art sustainability assessment. Such processes must: (i) address sustainability imperatives with positive progress towards sustainability; (ii) establish a workable concept of sustainability in the context of individual decisions/assessments; (iii) adopt formal mechanisms for managing unavoidable trade-offs in an open, participative and accountable manner; (iv) embrace the pluralistic inevitabilities of sustainability assessment, and (v) engender learning throughout. We postulate that sustainability assessment may be at the beginning of a phase of expansion not seen since environmental impact assessment was adopted worldwide.

Impact assessment has been in place for over 40 years and is now practised in some form in all but two of the world's nations. In this paper we reflect on the state of the art of impact assessment theory and practice, focusing on six well-established forms: EIA, SEA, policy assessment, SIA, HIA and sustainability assessment. We note that although the fundamentals of impact assessment have their roots in the US National Environmental Policy Act 1969 (NEPA) each branch of the field is distinct in also drawing on other theoretical and conceptual bases that in turn shape the prevailing discourse in each case, generating increasing degrees of specialisation within each sub-field. Against this backdrop, we consider the strengths and weaknesses of collective impact assessment practice, concluding that although there are substantial strengths, the plethora of specialist branches is generating a somewhat confusing picture and lack of clarity regarding how the pieces of the impact assessment jigsaw puzzle fit together. We use this 2 review to suggest an overarching research agenda that will enable impact assessment to evolve in line with changing expectations for what it should deliver.

We suggest that the impact assessment community has lost its way based on our observation that impact assessment is under attack because of a perceived lack of efficiency. Specifically, we contend that the proliferation of different impact assessment types creates separate silos of expertise and feeds arguments for not only a lack of efficiency but also a lack of effectiveness of the process through excessive specialisation and a lack of interdisciplinary practice. We propose that the solution is a return to the basics of impact assessment with a call for increased integration around the goal of sustainable development and focus through better scoping. We rehearse and rebut counter arguments covering silo-based expertise, advocacy, democracy, sustainability understanding and communication. We call on the impact assessment community to rise to the challenge of increasing integration and focus, and to engage in the debate about the means of strengthening impact assessment.

Abstract:This paper addresses the future of environmental assessment (EA)

Sustainability assessment as an ex ante tool for directing decision-making towards sustainability has emerged in a diverse range of forms across the world over the past decade or so. This broad practice of sustainability assessment embraces a wide and continually evolving range of processes, making the field potentially conceptually confusing and difficult to navigate. In recognition of this, there have been numerous attempts to develop conceptual frameworks to make sense of the diversity of practice. Through a process of literature review and reflection upon practice, this paper builds on earlier work, including our own, to develop a new descriptive conceptual framework for sustainability assessment. The conceptual framework distinguishes two dimensions of sustainability assessment, each with several sub-dimensions: sustainability concept (with sub-dimensions of underpinning sustainability discourse and representation of sustainability) and decision-making context (with sub-dimensions of subject of assessment, decision-question and responsible party). Drawing upon further literature, several examples of different approaches are then identified for each sub-dimension, demonstrating the range of approaches evident within current and emerging global practice. Within the 'sustainability concept' dimension, the first sub-dimension calls for critical reflection upon what the normative goal of the sustainability assessment is, while the second refers to how the concept of sustainability is represented in the decision-making process through the use of indicators. Although these two sub-dimensions are closely related their distinction is a key feature of the conceptual framework. The second dimension describes the practical context of a sustainability assessment. The proposed new conceptual framework enables a particular body of practice to be located within the broader field, as we demonstrate by categorising five examples of sustainability assessment according to the framework. We believe this framework has value to both researchers and practitioners, as a structure to guide sustainability assessment research and analysis and as the basis for comparing bodies of sustainability assessment practice within the range of possibilities defined by the contours of the framework. The framework encourages reflective practice, particularly in relation to how the concept of sustainability is understood and embedded within the process, and what the practice might deliver. This new conceptual framework is presented as a relatively simple road map and guide as sustainability assessment theorising and practice enters its second decade

One of the defining characteristics of sustainability assessment as a form of impact assessment is that it provides a forum for the explicit consideration of the trade-offs that are inherent in complex decision-making processes. Few sustainability assessments have achieved this goal though, and none have considered trade-offs in a holistic fashion throughout the process. Recent contributions such as the Gibson trade-off rules have significantly progressed thinking in this area by suggesting appropriate acceptability criteria for evaluating substantive trade-offs arising from proposed development, as well as process rules for how evaluations of acceptability should occur. However, there has been negligible uptake of these rules in practice. Overall, we argue that there is inadequate consideration of trade-offs, both process and substantive, throughout the sustainability assessment process, and insufficient considerations of how process decisions and compromises influence substantive outcomes. This paper presents a framework for understanding and managing both process and substantive trade-offs within each step of a typical sustainability assessment process. The framework draws together previously published literature and offers case studies that illustrate aspects of the practical application of the framework. The framing and design of sustainability assessment is vitally important, as process compromises or trade-offs can have substantive consequences in terms of sustainability outcomes delivered, with the choice of alternatives considered being a particularly significant determinant of substantive outcomes. The demarcation of acceptable from unacceptable impacts is a key aspect of managing trade-offs. Offsets can be considered as a form of trade-off within a category of sustainability that are utilised to enhance preferred alternatives once conditions of impact acceptability have been met. In this way they may enable net gains to be delivered; another imperative for progress to sustainability. Understanding the nature and implications of tradeoffs within sustainability assessment is essential to improving practice.

This paper argues that Governments have sought to streamline impact assessment