A proposal for integration of the ecosystem-water-food-land-energy (EWFLE) nexus concept into life cycle assessment: A synthesis matrix system for food security

Ensuring secure access to food and energy worldwide relies on win-win share of sectoral use of constrained natural resources such as land and water, taking also into account the crucial role of ecosystems and their services. The increase in global population and the related growing demand for food and other services are exerting unsustainable pressures on natural resources, compromising their use within the ecosystems’ carrying capacity. Progressively, studies and initiatives have been developed with the aim of identifying win-win share strategies, which may compensate the sectoral demands of natural resources, addressing the need of a holistic and interdisciplinary nexus approach. In this study, thus emphasizing the importance of a holistic approach and highlighting the fundamental role of ecosystems, we propose a synthesis matrix system that describes the complex and closely bound relationship between natural resources use for food (specifically water, land), energy (defined as ecosystem service flows in our matrix system) and ecosystems, along the lines of the concept of ecosystem-water-food-land-energy nexus. The synthesis matrix system could be defined for different scales, both from the global to the local scale and has been designed to include impacts and nexus with climate change. The matrix aims at integrating quantitative and qualitative aspects, which are often neglected in traditional approaches of impact assessment. The complexity of the interactions between the different components of the nexus requires relying not only on quantitative evidences but also on expert judgment. A sensitivity check has been conducted to illustrate how to verify the convergence of expert-judgment from different experts. Moreover, being the matrix meant for supporting holistic assessment of supply chain, in the present study, the integration of the matrix within life cycle assessment (LCA) is proposed. However, in order to support the analysis of interconnections among impacts, further methodological development of the LCA methods is needed. An illustrative example related to the competition for water, land and food bioenergy production is depicted. The matrices show that there are predominantly negative impacts given by sectoral uses of resources on the provision of ecosystem services, an issue that requires most focus on resource efficiency and on the environmental and economic impacts of natural resources use while reducing the trade-offs between the sectoral demands.