Extreme temperature trend and return period mapping in a changing climate in Upper Tekeze river basin, Northern Ethiopia

There is a consensus that global warming leads to the frequent occurrence of extreme temperature events that significantly impact human life, water resources, agricultural production, and ecosystems. However, the magnitudes of projected temperatures and the probabilities of extreme event occurrences are still deficient for robust planning and early warning efforts at major river basins. This study aimed to analyze extreme temperature trends and mapping return periods in a changing climate for the case of the upper Tekeze river basin, Northern Ethiopia. The future temperature is projected based on global climate models (GCMs) under RCP 4.5 and RCP 8.5 scenarios. The annual extreme temperatures were obtained from the daily temperature data series for the 12 stations by applying the block maxima series method. The non-parametric Mann-Kendall (M-K) statistical test was used for trend detection. The inverse distance weighted (IDW) method has been used to interpolate the point data and reveal the spatial patterns of the extreme temperature of the 50-year return period. The result shows the future extreme temperature will rise by 0.6–2.2 °C. Moreover, the future extreme temperature revealed a significant increasing trend in most of the stations (around 66.3%). The spatial extent of the 50-year return period of the extreme temperature map showed that in the future (2022–2051), the extreme temperature will be increased by 0.2–3.4 °C compared to the baseline period (1980–2009). The extreme temperature trend and return period mapping under climate change will help better local plans and fine-tune mitigation and adaptation measures.