*2.6.3 Evaluation of climate trends in the basins*

**Figure 4** presents the seasonal dynamics of precipitation and **Figure 5** of temperature for the reference and far future periods as illustrated by the median under RCP4.5 and RCP8.5 scenarios. Increasing temperature is projected in all study basins all year round under both scenarios, plus higher increases under the RCP8.5 compared to the RCP4.5. The highest increase in temperature is observed for the

#### **Figure 4.**

*Long-term monthly precipitation for the reference and far-future time slices as indicated by the climate models median of the climate projections under RCP 4.5 and RCP 8.5.*

#### **Figure 5.**

*Long-term monthly temperature for the reference and far-future time slices as indicated by the climate models median of the climate projections under RCP 4.5 and RCP 8.5.*

*Future Climate Change Impacts on River Discharge Seasonality for Selected West African River… DOI: http://dx.doi.org/10.5772/intechopen.99426*

Yobe River, reaching about 38°C in the month of may (RCP 8.5). Considering the precipitation dynamics in the Lokoja gauge of the Niger River located in central Nigeria, a moderate decrease at the beginning of the rainy season (from March to July), under both RCPs, is observed. Additionally, increasing precipitation is projected in Niger from July to November. A similar trend of a moderate reduction in rainfall at the start of the rainy season (June–July) is also observed for the Jama'are and Hadejia rivers. At the same time, an eventual increase is seen from July to November in the latter part of the year. The increase is from July to October in the Yobe, Jamaare, and Hadejia under both scenarios. Increasing precipitation is projected from June to November at Gashua (Yobe river). Biasutti [48] discovered decreasing rainfall in the start months (June–July) and increased rainfall in the end months (September–October), signifying a delay of the rainy season in West Africa. Refs. [49–51] also found a late beginning of the rainy season across Sahelian Africa because of a decrease in precipitation in July and August.
