Life cycle sustainability assessment in the context of sustainability science progress (part 2)

In the context of progress of sustainability science, life cycle thinking and, in particular, life cycle sustainability assessment may play a crucial role. Environmental, economic and social implications of the whole supply chain of products, both goods and services, their use and waste management, i.e. their entire life cycle from "cradle to grave" have to be considered to achieve more sustainable production and consumption patterns. Progress toward sustainability requires enhancing the methodologies for integrated assessment and mainstreaming of life cycle thinking from product development to strategic policy support. Life cycle assessment (LCA), life cycle costing (LCC) and social LCA (sLCA) already attempt to cover sustainability pillars, notwithstanding different levels of methodological development. An increasing concern on how to deal with the complexity of sustainability has promoted the development of life cycle sustainability frameworks. As a contribution to the ongoing scientific debate after the Rio+20 conference, this paper aims to present and discuss the state of the art of life cycle sustainability assessment (LCSA), giving recommendations for its further development in line with ontological, epistemological and methodological aspects of sustainability science. Building on the review about the state of the art of sustainability science and sustainability assessment methods presented in part I, this paper discuss LCA, LCC, sLCA and LCSA against ontological, epistemological and methodological aspects of ongoing scientific debate on sustainability. Strengths and weaknesses of existing life cycle-based methodologies and methods are presented. Besides, existing frameworks for LCSA are evaluated against the criteria defined in part I in order to highlight coherence with sustainability science progress and to support better integration and mainstreaming of sustainability concepts. LCSA represents a promising approach for developing a transparent, robust and comprehensive assessment. Nevertheless, the ongoing developments should be in line with the most advanced scientific discussion on sustainability science, attempting to bridge the gaps between the current methods and methodologies for sustainability assessment. LCSA should develop so as to be hierarchically different from LCA, LCC and sLCA. It should represent the holistic approach which integrates (and not substitutes) the reductionist approach of the single part of the analysis. This implies maintaining the balance between analytical and descriptive approaches towards a goal and solution-oriented decision support methodology.