Modelling Climate-Driven Changes in Agricultural Suitability Zones in the Guinea Savanna of Nigeria

Shifts in agro-climatic suitability zones driven by temperature rise and rainfall redistribution under projected climate change scenarios pose fundamental challenges to agricultural planning, food system stability, and rural livelihoods across Nigeria's Guinea Savanna belt spanning the North Central geopolitical zone. This study models current and projected future agricultural suitability for sorghum, groundnut, and cowpea across the Guinea Savanna zone using ensemble outputs from five CMIP6 global climate models downscaled to 5-kilometre resolution under SSP2-4.5 and SSP5-8.5 emissions pathways for the 2041 to 2060 horizon. The MaxEnt species distribution modelling approach was adapted to project bioclimatic envelope shifts under each scenario, while the FAO GAEZ model was applied to incorporate soil, terrain, and crop water requirement parameters into the suitability analysis. Empirical calibration data including meteorological observations from 22 stations and crop yield records from nine years of Benue, Kogi, and Niger State agricultural programmes were used to validate baseline model outputs. Results indicate that the combined Guinea Savanna agricultural suitability zone for sorghum contracts by 12 to 19 percent under SSP5-8.5 by mid-century, with the most severe losses projected along the southern boundary of the zone where increasing rainfall variability exceeds crop tolerance thresholds. Groundnut shows greater sensitivity than sorghum to temperature-driven evapotranspiration increases, with model-projected yield penalty of up to 23 percent under the high-emissions scenario. The study fills an important research gap in crop-specific, high-resolution suitability modelling for Nigeria's key agricultural transition zone and provides actionable projections for state-level agricultural adaptation planning. Keywords: climate change, agricultural suitability, Guinea Savanna, Nigeria, crop modelling.