Life Cycle Assessment and Carbon Footprint Methodologies in the Palm Oil Supply Chain: A Systematic Review of Approaches, System Boundaries, and Emission Hotspots

Abstract

A growing focus on openness in assessing environmental performance across agricultural supply chains has promoted the adoption of Life Cycle Assessment (LCA) and carbon footprint frameworks within the palm oil sector. This study systematically explores the implementation of these methodologies, placing particular emphasis on configuration choices, system boundary settings, and the identification of emission-intensive stages. A Systematic Literature Review (SLR) approach was employed, using the Scopus database as the primary source of peer-reviewed publications. The article selection followed a structured PRISMA-based screening process, resulting in 36 eligible studies published between 2020 and 2026. Data were collected exclusively from secondary sources and managed using reference organization tools to ensure consistency. The analysis was conducted through thematic synthesis, focusing on methodological patterns, boundary variations, and emission characteristics across the supply chain. The findings indicate that LCA, particularly attributional approaches, dominates current applications, while carbon footprint methods are frequently integrated to quantify greenhouse gas emissions. System boundary choices, especially the inclusion of land-use change, significantly influence emissions outcomes. Key emission hotspots are consistently identified at the plantation and milling stages, with reported emissions ranging from 0.8 to 4.5 t CO₂-eq per ton of crude palm oil depending on methodological assumptions. Despite variability, a gradual convergence toward more standardized practices is observed. In conclusion, methodological choices play a decisive role in shaping the outcomes of environmental assessment. Future research is encouraged to enhance methodological harmonization, integrate site-specific data, and expand system coverage to improve analytical consistency and transparency.