Including Ecosystem Services in Life Cycle Assessment: Methodology and Application to Urban Farms

Abstract

Conventional life cycle assessment (LCA) compares technological alternatives and chooses the one that has lower environmental impact, making it an approach for assessing relative sustainability. Such an approach largely ignores the role of ecosystem services (ES) and ecological carrying capacity, despite their essential role in sustaining all human activities. Such ignorance may lead to the over-dependence on scarce resources, perverse impacts on ecosystems, and lost opportunities for improvement. The framework of Techno-Ecological Synergy (TES) accounts for the demand and supply of ES at multiple spatial scales and defines metrics for absolute sustainability at both local and serviceshed scales. Applications of TES have been mainly focusing on localized systems. To prevent the shifting of impacts, a life cycle perspective is also needed. The authors have proposed the Techno-Ecological Synergy in Life Cycle Assessment (TES-LCA) framework by modifying each step in conventional LCA to incorporate the role of ecosystem goods and services. On one hand, TES-LCA advocates conventional solutions of impact reduction through technological improvements. On the other hand, it provides additional insights, including discovering novel ecological solutions to push toward absolute environmental sustainability. Thus, TES-LCA can offer a more comprehensive portfolio on sustainability performance evaluation. The substantial benefits of TES-LCA have been demonstrated by an application to urban farms.