Advancing quantification methods of sustainability: A critical examination emergy, exergy, ecological footprint, and ecological information-based approaches

Sustainability is increasingly used to describe a paradigm for shaping the social and economic future of mankind. While the concept of sustainability remains elusive, various attempts to construct a framework towards the quantification of sustainability have been made. In this paper, we review the attempts of emergy, exergy, ecological footprint, and the ecological information-based approach towards quantifying the concept of sustainability. Specifically, we review these methods based on their ability to address three criteria namely, the integration of ecological and economic dimensions, the long term resilience of a system, and the consideration of both extensive and intensive properties, e.g. properties that depend on system size and properties that do not. This paper is intended to provide a base for advancing the development of better methods for quantifying sustainability.