Environmental impacts of global industrial and smallholder oil palm plantations: historical dynamics and future climate risks.

Understanding the difference in environmental impact between industrial and smallholder plantations is essential for sustainable oil palm plantation management. In this study, we quantified the loss of forest cover, biomass, peatland, protected area caused by industrial and smallholder plantations from 1990 to 2019. We also analyzed the relationship between environmental impact with plantation type and export price. Results showed that in each continent, the environmental impact caused by industrial plantations per unit area has been generally higher than that of smallholders in the history, but there has been a trend to equal and exceed in recent years. After eliminating regional differences, industrial plantations exhibit significantly higher forest-loss proportions, average carbon loss density, and peatland-loss proportions than smallholders. In contrast, differences in protected-area loss are not statistically significant. Industrial plantations are more affected by market price fluctuations, leading to increased environmental impacts. Finally, this study also assesses the changes in suitable land for oil palm plantations under future climate change scenarios. Compared with RCP8.5, there will be more suitable areas for oil palm with higher suitability levels in the RCP2.6 scenario. The actual available suitable areas for oil palm will be less than 1/3 of the original when considering environmental impacts. In summary, this study quantified and compared the historical trend, regional distribution, and market-driven degree of environmental impact caused by industrial and smallholder plantations, and explored the multi-faceted trade-offs of oil palm plantations under future scenarios, which provides a decision-making basis for sustainable palm oil policies.