Climate-driven redistribution of agro-ecological zones in Ghana and its implications for agroecosystem sustainability.

Abstract

Understanding how sustained warming reshapes ecological boundaries remains a critical challenge in climate-ecosystem research, particularly across climate-sensitive regions of sub-Saharan Africa. Although temperature increases and land-cover change have been widely documented, the causal mechanisms linking climate variability to the redistribution of agro-ecological zones (AEZs) remain limited. Here we integrate multi-decadal land surface temperature (LST) and precipitation (PRE) datasets (1975-2025) with correlation analysis and nonlinear causal inference methods, including Extended Convergent Cross Mapping (ECCM) and its geographical extension (EGCCM), to examine climate-driven ecological restructuring in Ghana. Results reveal a significant warming trend of +2.39°C (≈0.47°C decade-1; p < 0.05), while precipitation shows strong inter-decadal variability without a significant long-term trend. During the same period, savanna systems expanded from 74,945 km2 to 128,355 km2, whereas forest ecosystems declined from 91,895 km2 to 60,070 km2. ECCM and EGCCM analyses identify temperature as the dominant driver of AEZ redistribution, demonstrating that sustained warming is reorganizing ecological boundaries and accelerating savanna-forest transitions across West Africa. These findings provide a causal and spatially explicit basis for prioritizing climate adaptation and land management strategies in regions most vulnerable to warming-driven ecological change.