A critical review of urban scale life cycle assessment of the built environment

Abstract

Considering that cities are responsible for a considerable share of energy consumption and GHG emissions, a complete environmental life cycle assessment (LCA) on an urban scale is gaining importance. This has led to numerous studies in this field of research, ranging from environmental impact investigation of building components (walls, insulation layers) to the carbon emission analysis of several buildings and networks, open spaces, and transportation facilities on a broader scale. This study aims to contribute to the field of research by conducting a comprehensive analysis of existing literature studies on varying scales. The primary objective is to determine whether the current studies have adequately addressed the gap in knowledge by effectively implementing Life Cycle Assessment (LCA) methodologies throughout the entire lifecycle of buildings while ensuring a sufficient level of detail and reliability in their findings. Additionally, this investigation seeks to evaluate the extent to which urban-scale LCA analyses have been undertaken in previous literature and assess the accuracy of the corresponding results. Furthermore, the study intends to identify the necessary measures that can be implemented to enhance the value and validity of these research outcomes. Ultimately, the findings of this research endeavor will identify the shortcomings and gaps in the current body of knowledge, thereby facilitating the development of a roadmap for future studies in this field of research. The gap analysis of this research field reveals important findings. Firstly, only 9% of previous studies have examined the entire urban scale, highlighting a significant research gap that should be addressed in future studies. Secondly, the bottom-up approach used in many studies introduces substantial uncertainty, necessitating improved modeling and uncertainty analysis. Thirdly, the building-by-building approach, while comprehensive, is time-consuming and costly, calling for research on enhancing its efficiency. Additionally, future studies should consider stock evolution beyond buildings, incorporate multiple LCA indicators, and integrate LCA with life cycle costing (LCC) in urban scale assessments. These identified gaps present promising avenues for future research in built environment LCA.