Identification of Rainfall and Temperature Trends in the Context of Climate Change for the Towns of Bol, Fianga, Moundou and N'Djamena in Chad

Climate change, characterised by extreme weather events, is one of the most serious threats to sustainable development, with expected adverse effects on human health and food security. Chad, which is half arid, is more than threatened by these increasingly frequent extreme hydrometeorological events, which will weaken its economy and have a negative impact on public health. The aim of this study is to identify rainfall and temperature trends in the context of climate change in the study area, which is made up of four (4) towns (N'Djaména, Bol, Fianga and Moundou) that are representative of Chad. They are divided according to bioclimatic zones, i.e. two in urban areas and two in rural areas. The selection criteria were based on previous malaria and cholera epidemiological situations. Of the 4 towns selected, two are considered to be endemic and at risk, and the other two are those that rarely experience epidemics. In situ observation data from observation stations in the study area will be used to identify obvious signals of climate change. To this end, an analysis of changes in annual precipitation and temperature over the last four (4) decades (1980-2023) was carried out before and after the detected break using statistical tests, as well as a trend and variability analysis of precipitation and extreme temperature indices.The results show that over the last few decades, there has been a change in the precipitation regime in terms of frequency and intensity at all sites.This general downward trend over the 1981-2020 series is linked to the extremely severe droughts of the 1980-1990 and 1990-2000 decades, marked by the El Niño phenomenon of 1983/1984 and a statistically significant increase in temperatures.The study thus contributes to modelling efforts to better predict the resurgence of climate-sensitive diseases.