Climate change plays a pivotal role in the hydrological dynamics of tributaries in the upper Blue Nile basin. The understanding of the change in climate and its impact on water resource is of paramount importance to sustainable water resources management. This study was designed to reveal the extent to which the climate is being changed and its impacts on stream flow of the Gumara watershed under the Representative Concentration Pathway (RCP) climate change scenarios. The study considered the RCP 2.6, RCP 4.5, and RCP 8.5 scenarios using the second-generation Canadian Earth System Model (CanESM2). The Statistical Downscaling Model (SDSM) was used for calibration and projection of future climatic data of the study area. Soil and Water Assessment Tool (SWAT) model was used for simulation of the future stream flow of the watershed. Results showed that the average temperature will be increasing by 0.84 °C, 2.6 °C, and 4.1 °C in the end of this century under RCP 2.6, RCP 4.5, and RCP 8.5 scenarios, respectively. The change in monthly rainfall amount showed a fluctuating trend in all scenarios but the overall annual rainfall amount is projected to increase by 8.6%, 5.2%, and 7.3% in RCP 2.6, RCP 4.5, and RCP 8.5, respectively. The change in stream flow of Gumara watershed under RCP 2.6, RCP 4.5, and RCP 8.5 scenarios showed increasing trend in monthly average values in some months and years, but a decreasing trend was also observed in some years of the studied period. Overall, this study revealed that, due to climate change, the stream flow of the watershed is found to be increasing by 4.06%, 3.26%, and 3.67%under RCP 2.6, RCP 4.5, and RCP 8.5 scenarios, respectively.

Climate change and its impact on surface runoff in the upper Blue Nile basin and sub-basins have been widely studied in future climate projections. However, the impact on extreme flow events of rivers is barely investigated discretely. In this paper, the change in temperature and rainfall under the Representative Concentration Pathway (RCP) highest emission scenario (RCP 8.5) and its impact on the high flow and low flow simulated by the Soil and Water Assessment Tool (SWAT 2012) in major watersheds of the Lake Tana Basin has been evaluated by comparing the baseline period (1971–2000) with the 2020s (2011–2040), 2050s (2041–2070), and 2080s (2071–2100). The high flows of watersheds were selected by the Annual Maximum Series (AMS) model, whereas the low-flow watersheds were selected by the 7-day sustained mean annual minimum flow method. The result showed that the highest change in maximum temperature ranged from 2.93 °C to 5.17 °C in monthly time scales in the 2080s. The increment in minimum temperature is also more prominent in the 2080s and it is expected to rise by 4.75 °C. Inter-annual variability of the change in rainfall has shown increasing and decreasing patterns. The highest increments are expected by 22.37%, 25.58%, and 29.75% in the 2020s, 2050s, and 2080s, respectively, whereas the projected highest decrease in rainfall dictates the decrease of 6.42%, 7.11%, and 9.26% in 2020s, 2050s, and 2080s, respectively. Due to changes in temperature and rainfall, the low flow is likely to decrease by 8.39%, 8.33%, 6.21%, and 5.02% in Ribb, Gumara, Megech, and Gilgel Abay watersheds, respectively, whereas the high flow of Gilgel Abay, Megech, Gumara, and Ribb watersheds are expected to increase by 13.94%, 12.16%, 10.90%, and 10.24%, respectively, every 30 years.

The study introduces the current situation of electric vehicle technologies, the possibilities and possible directions of their market, as well as the economic and environmental aspects in the eastern region of the EU, with special regard to Hungary. Our calculations show that despite the higher costs of ownership, in the case of 7 years of use (among Hungarian conditions), the total cost of the Battery Electric Vehicles (BEV) is lower than that of the Internal Combustion Engine Vehicles (ICEV) in each of the four segments analysed. The purchasing power of the population in the eastern regions of the EU is clearly lower compared to the western regions, yet people in this region spend beyond their financial means on motorization. Despite its unfavourable position, Hungary is in a particularly advantageous position compared to other countries in the region per vehicle and per capita in terms of the spread of BEVs. In the long run, even taking higher prices into account, the use of electric cars, in general, has significant advantages from an economic point of view; lower maintenance costs and fuel prices (especially with increased use) make EVs more cost-effective overall.

Soil erosion in the Ethiopian highlands poses a persistent threat to land productivity, downstream water bodies, and long-term watershed sustainability. While both climate change and land-use transitions are recognized as major drivers of erosion, their combined and relative effects remain insufficiently quantified at watershed scale. This study investigates how projected climate change and land-use change interact to shape future soil erosion dynamics in the Gumara–Maksegnit watershed, a critical tributary of Lake Tana in the Upper Blue Nile Basin. An integrated modeling framework was developed by coupling the Revised Universal Soil Loss Equation (RUSLE) with probabilistic climate projections and data-driven land-use simulations. Future rainfall was derived from five CORDEX-Africa regional climate models, bias-corrected and combined using Bayesian Model Averaging (BMA) to reduce model uncertainty and improve representation of rainfall erosivity. Land-use and land-cover changes were mapped for 2003 and 2023 using multi-temporal Landsat imagery and Random Forest classification, and future land-use patterns (2083) were simulated using an artificial neural network–based Cellular Automata approach. Soil erosion was quantified for historical, current, and future periods under land-use change only, climate change only (RCP4.5 and RCP8.5), and combined scenarios. Results indicate a continued expansion of cultivated land at the expense of forest and grazing areas, accompanied by a progressive increase in rainfall erosivity. Mean annual soil loss increased substantially from historical to current conditions and is projected to intensify further under future scenarios. Climate change exerts a stronger marginal influence on soil erosion than land-use change alone; however, their interaction amplifies erosion non-linearly, leading to the highest erosion rates under the combined land-use change and RCP8.5 scenario. Persistent erosion hotspots are concentrated on steep northern and northeastern slopes, where high topographic control coincides with limited conservation practices. The findings emphasize the importance of integrating climate uncertainty and land-use dynamics in soil erosion assessments and highlight the need for slope-targeted, climate-adaptive soil and water conservation strategies to mitigate future land degradation in the Upper Blue Nile highlands.---Getu Legese Abebaw is funded for his PhD study by the Scholarship for Christian Young People.