Evaluating Climate Change, Variabilities and Trends in Borkena Catchment, Awash Sub-Basin, Ethiopia

Climate change is a change in statistical descriptions of weather conditions, variations, averages, and extremes at a particular location caused by human activity. This study was conducted to analyze rainfall and temperature trends and variability in the upper awash sub-basin. Marksim software was used to download future climatic parameters. INSTAT Plus software was used to summarize the daily data into annual, and monthly totals. The rainfall and temperature indices were analyzed and trends were evaluated using Sen’s slope estimator and Mann–Kendall trend test. The baseline maximum temperatures in the study area had been increasing significantly, ranging from 0.1 − 1.6°C. The mean annual maximum temperature is likely to increase from − 2 to 3.1°C in 2040 and − 1.5 to 4°C in 2060 while the mean annual minimum temperature may change by a range of − 2.4 to 1.8°C in 2040 and − 1.9 to 2.9°C in 2060 as compared to the baseline. The mean annual Belg rainfall varied from 187.9 mm (CV 44.5%) in Kabie to 328.4 mm (CV 37.9%) in Haik respectively. The annual rainfall in the future predicted by GCMs varies by − 10.3 to 38.2% in 2040 and − 12.1 to 29.6% in 2060 respectively. The study area is susceptible to the influences of climate variability. Therefore, the precipitation and temperature variability of the area should be considered in climate change adaptation strategies.