Future evolution of surface temperature extremes and the potential impacts on the human health in Senegal

摘要

Climate change impacts negatively vulnerable regions such as West African countries like Senegal, through an increase of climate extremes. The objectives of this study is to analyze the future evolution of the extreme temperature events and their impacts on human health in Senegal during the cold (DJF), hot (MAM) and wet seasons (JAS) under the greenhouse gas scenarios RCP4.5 and RCP8.5 using Climate projections of five (5) regional climate models (RCMs) of the Coordinated Regional Climate Downscaling Experiment (CORDEX) program. The results show that the biases of the RCMs are globally low especially their ensemble mean of the RCMs. This ensemble mean was afterwards considered in the analysis of the climate extremes in the near (2021-2050) and far future (2071-2100). When considering the near future, the frequency of the hot nights (Tn90p) increases under the scenario RCP8.5 (up to 90%) during the rainy season in the south of the country. As for the percentage of the hot days (Tx90p), it may reach approximately 70% under the scenario RCP8.5 in DJF over the majority of the country. Moreover, a strong increase of Tn90p and Tx90p is also diagnosed during the far future with values exceeding 80% over most parts of the country. Concerning the evolution of the heat wave magnitude index-daily, the ensemble mean of all models shows that the heat waves are more severe in MAM and JAS under both scenarios during the near and the far future over most parts of the country. To estimate the potential impacts of this heat stress on the human health, the heat index and the humidex are used. The analysis of the heat index shows that the sanitary risks are more perceptible over the whole country during the rainy season with values reaching the symptom band II for both scenarios during the far future. As for the humidex, it is characterized by a gradual increase from the historical period to the far future. This analysis highlights the fact that appropriate adaptation measures should be considered to tackle efficiently the increase of temperature extremes which may impact negatively the human health.