This study investigated the impacts of climate change on the hydrology of the Upper Awash Basin, Ethiopia. A soil and water assessment tool (SWAT) model was calibrated and validated against observed streamflow using SWAT CUP. The Mann–Kendall trend test (MK) was used to assess climate trends. Meteorological drought (SPEI) and hydrological drought (SDI) were also investigated. Based on the ensemble mean of five global climate models (GCMs), projected increases in mean annual maximum temperature over the period 2015–2100 (compared with a 1983–2014 baseline) range from 1.16 to 1.73 °C, while increases in minimum temperature range between 0.79 and 2.53 °C. Increases in mean annual precipitation range from 1.8% at Addis Ababa to 45.5% over the Hombole area. High streamflow (Q5) declines at all stations except Ginchi. Low flows (Q90) also decline with Q90 equaling 0 m3s−1 (i.e., 100% reduction) at some gauging stations (Akaki and Hombole) for individual GCMs. The SPEI confirmed a significant drought trend in the past, while the frequency and severity of drought will increase in the future. The basin experienced conditions that varied from modest dry periods to a very severe hydrological drought between 1986 and 2005. The projected SDI ranges from modestly dry to modestly wet conditions. Climate change in the basin would enhance seasonal variations in hydrological conditions. Both precipitation and streamflow will decline in the wet seasons and increase in the dry seasons. These changes are likely to have an impact on agricultural activities and other human demands for water resources throughout the basin and will require the implementation of appropriate mitigation measures.

Pastoralism is a fragile livelihood system for millions of people around the world and a significant number of that is found in Africa. Proper documentation and understanding of indigenous knowledge and strategies on pastoralism are limited and this study sheds light on location-specific indigenous knowledge and corresponding perceptions of local communities with the support of metrological patterns of weather and climate variability. This is an exploratory study that draws on orally existing indigenous knowledge of adaptation from qualitative data sources, analyzes climate data, and matches it with communities' oral records of major climatic events to validate the accuracy of their perceptions. The results reveals that there is a high climate variability as indicated with a Coefficient of Variation (CV) value of 30, the PCI indicated high rainfall intensity and longer dry periods indicated by the SI values. Almost every year the SI value predicted longer dry season. The community’s perception matched with recorded climate data of the past 36 years and identified 10 major climate extremes orally recounted down in history. Indigenous strategies include indigenous weather forecasts, mating calendar, destocking, herd mobility, herd diversification, traditional rotational grazing system (‘Seri’), and also lists of emerging adaptation strategies utilized as a result of the severity of climate variability and extremes in the region. The results indicates that uncommon adaptation strategies are replacing preexisting pastoralist livelihood system and that indigenous strategies are in need of support to withstand the current and predicted weather and climate variability in the sites. Pastoralists and agro-pastoralists will be in a better position to adapt to the consequences of climate variability and extremes if indigenous institutions are revitalized with innovations.