Sustainable composites for metal replacement: Environmental assessment and material selection of fiber-reinforced polymer across industries

• LCA reveals life cycle trade-offs in FRP use across key industrial applications. • Fiber and resin synthesis drive upstream GHG emissions and energy intensity. • Functional units and boundary choices limit consistency in FRP LCA results. • Recycling challenges persist; circular economy remains underexplored in FRP LCAs. • Decarbonizing FRPs needs LCA harmonization, circular strategies, and policies. The urgent necessity to mitigate climate change and reduce resource depletion is accelerating the shift toward sustainable materials in critical industries. Fiber-reinforced polymer (FRP) has been gaining attention as an alternative to steel and aluminum in construction, automotive, and pipeline applications due to its exceptional high-performance properties. However, the environmental implications of FRP remain a concern, predominantly due to energy-intensive production processes and end-of-life (EoL) challenges. This review offers a comprehensive, cross-sectoral analysis of life-cycle assessment (LCA) findings on FRP, highlighting sector-specific drivers, environmental trade-offs, and methodological limitations. Although use-phase benefits, such as reduced emissions and lower maintenance costs, are well documented, they are often offset by the high embodied energy and underdeveloped recycling infrastructure. Existing LCA studies have emphasized climate impacts, while underrepresenting various indicators, including human toxicity, resource depletion, and circularity. Methodological limitations, such as generic datasets, a lack of performance-based functional units, and simplified EoL modeling, compromise comparability. Mechanical recycling often yields low-quality output with reduced performance, limiting reuse in high-value applications, whereas thermal and chemical methods face challenges in energy and scalability. Future efforts must prioritize standardized LCA methods, region-specific background datasets, circular economy integration, and advanced recycling technology to realize the full sustainability potential of FRP. A strategic framework is necessary to enable the widespread use of FRP as a viable, low-carbon alternative in a net-zero future.