A comparative synthesis of environmental sustainability in smallholder oil palm systems in Southeast Asia and Sub-Saharan Africa

Smallholder oil palm (OP) systems are central to rural livelihoods and global vegetable oil supply, yet the evidence base informing their environmental management is heavily concentrated in Southeast Asia (SEA). At the same time, OP cultivation is expanding across Sub-Saharan Africa (SSA), where production systems differ markedly. The uneven distribution of research and the rapid growth of the sector in Africa create a need for careful comparative synthesis to clarify where lessons are transferable and where they are not. This review compares smallholder OP systems in SEA and SSA to examine how contrasting development histories, agronomic practices, and governance shape current and future potential for environmental sustainability. This review synthesises evidence on nutrient management, soil fertility, yield potential, greenhouse gas emissions, crop residue management, and institutional constraints. SEA systems are generally characterised by higher external inputs, established processing infrastructure, and more developed certification and policy frameworks, alongside well-documented challenges related to nutrient losses, soil degradation, and emissions. In contrast, many SSA systems operate under lower-input, resource-constrained conditions, with complex land tenure systems, resulting in distinct productivity and environmental profiles. Rather than assuming a common development trajectory, the review highlights major differences that influence environmental performance across regions. By distinguishing between context-specific challenges and potentially transferable practices, this synthesis provides a clearer evidence base for researchers, policymakers, and practitioners working to improve the sustainability of smallholder OP systems.