Heat waves on land, in lakes and in the ocean will increase considerably in magnitude and duration with increasing global warming . Under a 1.5ºC-compatible scenario, children born in Africa in 2020 are likely to be exposed to 4-8 times more heat waves compared to people born in 1960, increasing to 5-10 times for 2.4℃ global warming. The annual number of days above potentially lethal heat thresholds reaches 50- 150 in west Africa at 1.6°C global warming, 100-150 in central Africa at 2.5°C, and 200-300 over tropical Africa for >4°C. 
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report