Potential impact of 1.5, 2 and 3 °C global warming levels on heat and discomfort indices changes over Central Africa

Investigating the effects of the increased global warming through the lens of the Paris agreements would be of particular importance for Central African countries, which are already experiencing multiple socio-political and socio-economic constraints, but are also subject to severe natural hazards that interact to limit their adaptive capacity and thus increase their vulnerability to the adverse effects of climate change. This study explores changes in heat stress and the proportion of population at risk of discomfort over Central Africa, based on an ensemble-mean of high-resolution regional climate model simulations that cover a 30-year period, under 1.5, 2 and 3 °C Global Warming Levels (GWLs). The heat index was computed according to Rothfusz's equation, while the discomfort index was obtained from Thom's formula. The results show that throughout the year but with a predominance from March to August, the spatial extent of both heat and discomfort categories is projected to gradually increase according to the considered GWLs (nearly threefold for an increasing warming thresholds from 1.5 to 3 °C). As these heat conditions become more frequent, they lead to the emergence of days with potentially dangerous heat-related risks, where almost everyone feels discomfort due to heat stress. It thus appears that the majority of populations living in countries located along the Atlantic coast and in the northern and central part of the study area are likely to be more vulnerable to certain health problems, which could have repercussions on the socio-economic development of the sub-region through decreased workers’ productivity and increased cooling degree days. Overall, these heat-related risks are more extended and more frequent when the GWL reaches 2 °C and above.