Which lands in Ethiopia will become more suitable for irrigation as the climate changes?

Climate change is reshaping water resources and agriculture, especially in places like Gardulla in southern Ethiopia. A research team examined the feasibility of surface irrigation using weather, topography, soil, land‑cover and proximity data. They weighted each factor with the Analytic Hierarchy Process (AHP) and a weighted overlay, while future climate projections came from the statistical downscaling model SDSM4.2, based on SSP2‑4.5 and SSP5‑8.5 pathways.

Under current conditions, 8 % of the area is highly suitable for irrigation, 54.3 % moderately suitable, 30 % marginal, and 2.3 % unsuitable. Looking ahead to the 2050s and 2080s, highly suitable land rises to 10.8 % (SSP2‑4.5) and 13.5 % (SSP5‑8.5), while unsuitable zones drop almost to zero. In surface terms, suitable land expands by 1,357‑6,868 hectares depending on the scenario.

The message is clear: future climate will enlarge irrigation‑friendly zones, but only if local policies keep pace. The authors recommend smart, community‑managed irrigation systems to cut water loss and secure sustainable farming.

The irrigation suitability analysis employed a multicriteria decision‑making framework. The Analytic Hierarchy Process (AHP) structured the decision into a hierarchy of criteria—climate, soil, topography, land cover, and distance to water sources—and assigned relative weights through pairwise comparisons. These weights were then integrated into a raster weighted overlay to produce a composite suitability map.

For climate projections, the SDSM4.2 (Statistical DownScaling Model) was calibrated using local observations and outputs from global climate models (GCMs). Two Shared Socio‑Economic Pathways were selected: SSP2‑4.5, representing a moderate mitigation scenario, and SSP5‑8.5, depicting a high‑emission future. Downscaled climatic variables included annual precipitation, mean temperature, and potential evapotranspiration, all crucial for crop water balance calculations.

Suitability maps were interpolated using Inverse Distance Weighted (IDW) to fill gaps and ensure spatial continuity. Results reveal a trend toward expanding highly suitable areas, driven mainly by increased seasonal rainfall during critical irrigation periods. Nonetheless, inter‑annual variability remains high, implying that water‑management strategies must incorporate flexible storage and distribution systems.

Territorial planning implications are substantial: authorities should embed suitability maps into land‑use plans, prioritize investments in low‑loss irrigation infrastructure (e.g., lined canals), and promote climate‑smart agricultural practices such as crop rotation and drought‑tolerant varieties. Community participation in water governance can further enhance resilience, reduce water‑conflict potential, and ensure a more equitable distribution of agricultural benefits.