Analysis of climate trend, variability and its implications on bread wheat (Triticum aestivum L.) productivity in central highlands of Ethiopia

Climate change is a global threat with localized geographic and socioeconomic impacts that directly related to agricultural productivity and sustainability. This study assessed the spatio-temporal variability and trend of rainfall, temperature and growing season characteristics and their impact on bread wheat in the central Highlands of Ethiopia. Long-term (1989–2020) daily rainfall and temperature data of the study locations were collected from Ethiopian Meteorological Institute. Climate variability was analyzed using Coefficient of Variation, Precipitation Concentration Index, and Standardized Anomaly Index indices. Trend analysis were determined by Mann–Kendall trend test and Sen’s slope tests. Growing seasons characterized by INSTAT+ 3.37 statistical software while impact of climate variability on wheat yield was assessed using combined multiple regression analysis. Rainfall was temporally and spatially variable and recorded below the long term mean in 58% of the study years. Both maximum and minimum temperatures were significantly increasing (p < 0.01) by 0.043–0.081 °C and 0.034–0.094 °C per year respectively, over the period 1989 to 2020. Analysis of growing season characteristics indicated the shifting of crop calendar in which the start of the rainy season ranged from June 13 (165 DOY)—July 6 (188 DOY). The end of the rainy season ranged from October 10 (284 DOY)—November 2 (307 DOY), and the length of the growing period ranged from 96–136 days. The results also indicated that assessed climate variables explain 17–83% of the change in wheat yield at selected study sites. These climate shifts disrupt farming calendars, trigger crop failures and threatening food security. To adapt, farmers must switch to early-maturing, drought-tolerant crop varieties and implement soil moisture conservation.