Sustainability assessment has recently emerged as a policy tool whose fundamental purpose is to direct planning and decision-making towards sustainability. Its foundations lie in well-established practices such as project environmental impact assessment (EIA) and the more recent experience with strategic environmental assessment (SEA) applied to policies, plans and programmes. The distinguishing feature of sustainability assessment when compared with other, more established forms of impact assessment and planning is that the complex and ambiguous concept of sustainability lies at its heart.
Two broad forms of sustainability assessment can be distinguished that reflect slightly different origins. In parts of Western Europe sustainability assessment follows an SEA model with a planning focus, an example being the well-established sustainability appraisal process in the UK that applies to land-use plans. In jurisdictions where development is driven more by major infrastructure projects than by planning, such as Canada and Western Australia, sustainability assessment follows a model more closely related to project-level EIA.
It is also useful to distinguish between ‘external’ sustainability assessment, conducted by regulatory bodies for the purpose of project approval for example, and ‘internal’ sustainability assessment conducted by planners and project proponents as part of the process of developing a proposal. Both are important if we are to shift towards more sustainable decision-making. However, the emphasis in Western Australia at present is very much on internal forms of sustainability assessment being conducted voluntarily by public infrastructure providers and the corporate sector. Unfortunately, after demonstrating leadership and innovation in trialing external, regulatory sustainability assessment in the cases of the Gorgon gas development and the South West Yarragadee water supply system proposals, the Government has shown little interest in progressing further in this direction.