Effects of rainfall and temperature variabilities on coffee (Coffea arabica L.) productivity in eastern Ethiopia

Abstract Coffee production in eastern Ethiopia is highly sensitive to rainfall variability and rising temperatures. Understanding the relationship between seasonal climate characteristics and coffee yield is critical for sustaining livelihoods and export potential. This study examined rainfall and temperature patterns in Melka Balo, Bedeno, and Shenen Dugo districts, analyzing eighteen years of daily climate and yield data (2007–2024) and projected future trends (2026–2055) using CMIP6 models under the SSP2-4.5 scenario. Correlation analysis revealed that belg rainy days had a strong positive influence on coffee yield, while belg and kiremt rainfall totals, kiremt rainy days, and length of the growing period showed moderate positive effects. Conversely, delayed onset of rainfall reduced yield, and both belg and kiremt mean temperatures exhibited strong negative correlations. Regression models explained 82–92% of yield variation across districts, confirming rainfall reliability as a key driver of productivity. Projection results indicated that belg rainfall totals will decline sharply (~ 3.7–9.8 mm per year), kiremt rainfall totals will decrease slightly but variably (~ 0.5–9 mm per year), and annual rainfall will decline steadily (~ 4.6–9 mm per year). The onset of belg rainfall is expected to be delayed by 0.7–1.2 days per year, while the end date shifts earlier by ~ 2–4 days per year, shortening the growing period by ~ 0.7–6 days annually. Seasonal temperatures will rise consistently, with belg mean increasing by ~ 0.035–0.039°C per year, kiremt mean by ~ 0.021–0.032°C per year, and mean annual temperature by ~ 0.02–0.03°C per year. Coffee yield is projected to decline steadily, averaging ~ 0.09–0.10 qt/ha loss per year. Climate variability, particularly rising belg and kiremt temperatures, declining rainfall totals, delayed onset, earlier cessation, and shortened growing periods, poses a severe threat to Arabica coffee production in eastern Ethiopia. Without adaptation, both livelihoods and export potential will be undermined. Urgent measures such as introducing drought and high temperature-resistant coffee varieties, expanding production to higher altitudes, integrating shade trees, and implementing soil and water conservation strategies are essential to sustain productivity under changing climate conditions.