Exploring carbon neutrality scenarios through the life cycle assessment lens: a review of literature and methodological challenges

Abstract National carbon neutrality scenarios usually focus on territorial greenhouse gas (GHG) emissions. Their implementation could thus possibly result in some impact transfers to life cycle steps outside the territory or to other environmental issues. Life Cycle Assessment (LCA) could help to assess comprehensively these scenarios. In this perspective, this article provides a comprehensive review of the current state of the art regarding the combination of LCA and carbon neutrality. An analysis of the identified articles covers general characteristics and methods, including the definition of carbon neutrality, the functions and boundaries of LCA, the life cycle inventory, the impact assessment, and the choices of LCA modelling. The findings indicate an increasing interest in the environmental assessment of decarbonisation options, particularly in energy transition scenarios. However, carbon neutrality strategies extend beyond energy transformation alone. They require modifications in agriculture, industrial processes, and waste treatment, among other sectors. According to the evidence collected from this research, there are very few articles that incorporate LCA within a national carbon neutrality strategy, encompassing all GHG-emitting sectors. Valuable insights can be gleaned from the identified publications that evaluate complex systems with LCA, such as policies, scenarios, cities, and other macroscopic objects, relying on advanced LCA methodologies. Some challenges are still to be found, and future work will focus on the application of LCA to a specific national scenario aiming at reaching carbon neutrality on a territory for 2050.