• Energy Research

Abstract. The strategies and actions in the management of African River Basins in a warming climate environment have been studied. Using the Gurara Reservoir Catchment in North-West Nigeria as a case study, summations were proposed using hypothetical climate scenarios considering the Global Climate Models prediction and linear trend of the data. Four (4) proposed scenarios of temperature increase (1 % and 2 %) coupled with a decrease in precipitation of (−5 % and −10 %) were combined and applied for the study area. The Water Evaluation and Planning Tool was used to model and evaluates the impact of the earth's rising temperature and declining rainfall on the hydrology and availability of water by investigating its resilience to climate change. Modelling results indicate a reduction in available water within the study area from 4.3 % to 3.5 % compared to the baseline with no climate change scenario, revealing the current water management strategy as not sustainable, uncoordinated, and resulting in overexploitation. The findings could assist in managing future water resources in the catchment by accentuating the need to put in place appropriate adaptation measures to foster resilience to climate change. Practically, it is pertinent to shape more effective policies and regulations within catchments for effective water resources management in reducing water shortage as well as achieving downstream water needs and power benefit in thefuture, while also allowing flexibility in the operation of a reservoir with the ultimate goal of adapting to climate change.

Abstract This study aimed to compare the performance of six regional climate models (RCMs) in simulating observed and projecting future climate in the Savannah zone of Ghana, in order to find suitable methods to improve the accuracy of climate models in the region. The study found that the accuracy of both individual RCMs and their ensemble mean improved with bias correction, but the performance of individual RCMs was dependent on location. The projected change in annual precipitation indicated a general decline in rainfall with variations based on the RCM and location. Projections under representative concentration pathway (RCP) 8.5 were larger than those under RCP 4.5. The changes in mean temperature recorded were 1 °C for the 2020s for both RCPs, 1–4 °C for the 2050s under both RCPs, and 1– 4 °C under RCP 4.5, and from 2 to 8 °C for the 2080s. These findings will aid farmers and governments in the West African subregion in making informed decisions and planning cost-effective climate adaptation strategies to reduce the impact of climate change on the ecosystem. The study highlights the importance of accurate climate projections to reduce vulnerability to climate change and the need to improve climate models in projecting climate in the West African subregion.

Abstract Irrigation is important for food security, however, water requirements for sustainable irrigation may be affected by climate change. The study analysed water requirements of two commonly cultivated crops in the dry season in the Ghanaian Savannah regions under baseline and future periods. Crop water requirement (CWR) and crop irrigation requirement (CIR) were lowest in baseline periods and increased in the 2020s, 2050s, and 2080s for RCP 4.5 and RCP 8.5 at all locations. CIR was higher for tomato as compared to onions for most locations. Seasonal changes in the CWR ranged from 2–9, 3–12, and 3–12% and 2–8 3–12% and 5–18% for the 2020s, 2050s and 2080s under RCP 4.5 and RCP 8.5, respectively, for both the crops. Bole and Zuarungu recorded highest increases in CWR for tomato, whereas the least change was observed at Yendi for onions. Changes in seasonal CIR ranged from 3–19, 2–21, and 6–22%, respectively, for the 2020s, 2050s and 2080s for RCP 4.5. Under RCP 8.5, changes in seasonal CIR ranged from 3–23, 5–23, and 6–27% were observed for the 2020s, 2050s, and 2080s, respectively. Highest increases in CIR were noticed at Bole and Zuarungu for tomato, whereas the least change was observed at Wenchi for onions. Findings of the study support zero hunger and climate action, goals 2 and 13 of the Sustainable Development Goals (SDGs). HIGHLIGHTS The study analysed water requirements of two commonly cultivated crops in the dry season in the Savannah regions of Ghana. Crop and irrigation water requirements were generally lowest in baseline periods and increased in the 2020s, 2050s, and 2080s under RCP 4.5 and RCP 8.5. Highest increases in irrigation requirement were noticed at Bole and Zuarungu for tomato, whereas the least change was observed at Wenchi for onions.