Modeling Future Rainfall Trends and Patterns Under Moderate and High Emission Scenarios in West Shewa, Oromia Region, Ethiopia

Understanding future rainfall variability is crucial for climate resilience planning in rain-fed agricultural regions like West Shewa in Ethiopia. This study investigated projected rainfall patterns under moderate (SSP245) and high (SSP585) emission scenarios using an ensemble of bias-corrected CMIP6 models: BCC-CSM2-MR, MRI-ESM2-0, and GFDL-ESM4. Future estimates (2030-2089) were analyzed using statistical methods such as the Mann-Kendall trend test, Sen's slope estimator, rainfall anomaly index, and Standardized Precipitation Index (SPI). Results suggest a significant increase in annual and seasonal rainfall, particularly during the Kiremt and Bega seasons in the near term (2030-2059), with more pronounced increases under SSP585. However, the strength and significance of these trends tend to diminish toward the end of the century (2060-2089), indicating potential future instability and uncertainty in rainfall patterns. SPI analyses further highlight the growing frequency of both wet and dry anomalies, especially under the high-emission pathway, suggesting an increased likelihood of extreme hydrological events. These anticipated changes provide both opportunities and challenges: higher rainfall may alleviate drought-related stress, but it may also increase flood risks and disrupt existing water resource management techniques. The findings highlight the necessity of strategies for adaptation such as climate-smart agriculture, early warning systems, and long-term land use planning in West Shewa to protect livelihoods and ecosystems. Overall, this study provides useful localized insight into future climatic scenarios, which can help policymakers and communities prepare for increased climate resilience.