Decarbonizing the Built Environment: A Critical Review of Systemic Gaps and Future Pathways

Abstract

As built-environment carbon research expands from quantification toward mitigation decision support, a central unresolved question is whether reported carbon advantages remain valid under the conditions governing real decisions and implementation. This review integrates bibliometric mapping and structured full-text synthesis of 112 studies on buildings and road-transport infrastructure to identify systemic gaps across operational emissions, embodied carbon, and life cycle assessment. Reported outcomes were consistently conditioned by system boundaries, functional units, service life, spatial scale, data provenance, background energy and material systems, and implementation constraints. Interventions can also redistribute rather than simply eliminate emissions across lifecycle stages, supply chains, maintenance cycles, and time; consequently, neither process-level reductions nor nominal technology labels reliably indicate whole-system decarbonization without considering the configuration through which emissions are changed. Across the literature, analytical capability has advanced faster than evidence linking modeled mitigation potential to feasible implementation and verified reduction. Prediction, scenario analysis, optimization, and digital tools strengthen assessment and decision support but might not by themselves establish causal effectiveness, feasibility, or persistent mitigation. The review, therefore, reframes built-environment decarbonization from identifying universally superior technologies toward determining the conditions under which carbon evidence remains decision-valid. Future progress requires stage-adaptive information, decision-sensitive uncertainty analysis, feasibility-aware intervention selection, and stronger post-decision verification to preserve evidence integrity from assessment through implementation.