A Critical Evaluation of Methods for the Assessment of Environmental Sustainability of Engineering Supply Chains

Abstract

Engineering supply chains face increasing pressure to minimize carbon emissions in line with international climate targets. However, existing approaches for assessing carbon emissions are limited in their ability to capture the complexity of engineering supply chains, particularly during early design stages. Methods such as Life Cycle Impact Assessment and standards including ISO 14064 provide general guidance but lack methodological specificity for capturing indirect carbon emissions and supporting early decision-making. This paper presents a critical review of carbon emissions assessment methods applicable to engineering supply chains. A structured literature review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses approach to ensure transparency and reproducibility. The analysis evaluates the applicability of current methods, their integration with engineering design processes, and their feasibility during early design stages when data are limited. Challenges are identified, including the neglect of indirect emissions, complex system boundary definitions, and the lack of support for iterative design workflows. To address the challenges, methodological requirements are proposed for future carbon assessment methods. These include the capacity to handle data uncertainty, alignment with design decisions, and definition of appropriate system boundaries. The findings highlight the need for a carbon emissions assessment approach that can operate under limited data conditions, support early design decision-making, and capture the complexity of engineering supply chains. The novelty of this study lies in its review of existing methods and standards to highlight methodological requirements that allow carbon assessment during early design stages.

Received: 28 August 2025 | Revised: 11 December 2025 | Accepted: 28 February 2026

Conflicts of Interest

The authors declare that they have no conflicts of interest to this work.

Data Availability Statement

Data are available from the corresponding author upon reasonable request.

Author Contribution Statement

Nur Dini Binti Zupli: Conceptualization, Methodology, Validation, Formal analysis, Investigation, Resources, Writing – original draft, Writing – review & editing, Visualization, Project administration, Funding acquisition. Alison McKay: Validation, Resources, Writing – review & editing, Supervision. Richard Chittenden: Validation, Resources, Writing – review & editing, Supervision.