Regional water stress dynamics in oil palm under ENSO in Malaysia and Indonesia using 22-year multiple climate data

Abstract The increasing frequency of El Niño-Southern Oscillation (ENSO) events due to climate change poses significant challenges to oil palm production, highlighting the need for effective adaptation strategies. However, few studies have examined the regional heterogeneity of climate stressors. This study investigates regional climate risks to oil palm during ENSO phases to support effective adaptation in Malaysia and Indonesia. We analyzed 22 years of annual Fresh Fruit Bunch (FFB) yield data and seven climate variables representing soil, atmosphere, water input, and plant water status. Regions highly sensitive to ENSO were identified, and Pearson correlation analysis was used to examine seasonal relationships between FFB yield and each variable. Climate anomalies during ENSO phases were assessed to determine regional impacts, and key climate risk variables were identified. GRACE satellite data was used for validation. The results revealed that elevated atmospheric vapor pressure deficit (VPD) particularly affected regions in the Malay Peninsula during El Niño. GRACE data indicated that water deficits were the dominant stressor during El Niño, while non-water-mass-related factors also contributed to reduced FFB yields during La Niña. These findings provide insights for jurisdiction-level adaptation planning to enhance climate resilience in the oil palm sector.