Heat stress: adaptation measures in South African informal settlements

Abstract

Globally extreme weather events are experienced most acutely in cities. While formal settlements can respond to such events, informal settlements are often vulnerable and illprepared. Sub-Saharan Africa is rapidly urbanising with informal settlements that require effective climate change adaptation measures. Two climate adaptation strategies for informal dwellings are considered for their success under 2100 Intergovernmental Panel on Climate Change (IPCC) climate scenarios. Using existing data collected from informal dwellings in South Africa, the findings from a digital simulation study reveal that cool roof paints can currently lower excessive heat stress conditions by 42-63% when applied to high thermal mass dwellings with poorly insulated lightweight corrugated sheeting roofing. However, for the future 2100 climate scenarios this strategy only lowers excessive heat stress conditions by 12-17%. This calls for the development of integrated multifaceted heat stress adaptation strategies for informal settlements in Sub-Saharan Africa. PRACTICE RELEVANCEThis study assessed heat stress conditions and the application of two financially and practically feasible heat stress adaptation strategies in informal dwellings in South Africa. This involved assessing the efficacy of using cool roof paints and improved thermal insulation under current and future climate change-affected conditions. The findings reveal that Southern African informal dwellings experience extreme heat stress 32% of the time. Predicted climate change-affected conditions will increase heat stress exposure up to 40% over a full year. The study reveals that cool roof paints can improve the performance of uninsulated, low thermal mass homes in temperate climates by lowering heat stress conditions by 42-63%, yet this climate change adaptation strategy is only an interim solution with limited success (12-17% improvement) under future 2100 climate change-affected conditions. As a result multilayered integrated heat amelioration strategies are needed in informal communities. 56 Hugo Buildings and Cities