Current and Potential Future Seasonal Trends of Indoor Dwelling Temperature and Likely Health Risks in Rural Southern Africa

Abstract

Climate change has resulted in rising temperature trends which have been associated with changes in temperature extremes globally. Attendees of Conference of the Parties (COP) 21 agreed to strive to limit the rise in global average temperatures to below 2 °C compared to industrial conditions, the target being 1.5 °C. However, current research suggests that the African region will be subjected to more intense heat extremes over a shorter time period, with projections predicting increases of 4–6 °C for the period 2071–2100, in annual average maximum temperatures for southern Africa. Increased temperatures may exacerbate existing chronic ill health conditions such as cardiovascular disease, respiratory disease, cerebrovascular disease, and diabetes-related conditions. Exposure to extreme temperatures has also been associated with mortality. This study aimed to consider the relationship between temperatures in indoor and outdoor environments in a rural residential setting in a current climate and warmer predicted future climate. Temperature and humidity measurements were collected hourly in 406 homes in summer and spring and at two-hour intervals in 98 homes in winter. Ambient temperature, humidity and windspeed were obtained from the nearest weather station. Regression models were used to identify predictors of indoor apparent temperature (AT) and to estimate future indoor AT using projected ambient temperatures. Ambient temperatures will increase by a mean of 4.6 °C for the period 2088–2099. Warming in winter was projected to be greater than warming in summer and spring. The number of days during which indoor AT will be categorized as potentially harmful will increase in the future. Understanding current and future heat-related health effects is key in developing an effective surveillance system. The observations of this study can be used to inform the development and implementation of policies and practices around heat and health especially in rural areas of South Africa.

Impacts of Climate Change on Health and Wellbeing in South Africa

“…Observed rates and modelled projections indicate that warming over southern Africa is happening at twice the global rate [ 48 ]. Unless concerted international action is taken to reduce greenhouse gas emissions, temperatures may rise more than 4 °C over the southern African interior by 2100, with increases of more than 6 °C over large the western, central and northern parts of the country, which have faced several years of droughts [ 30 , 49 ]. Relative to a 1981–2000 base period, the probability of summer heat waves over South Africa has increased by over 3.5 fold [ 50 ].…”

“…Relative to a 1981–2000 base period, the probability of summer heat waves over South Africa has increased by over 3.5 fold [ 50 ]. Impacts of heat waves differ from the more insidious, but no less harmful, rises in heat that increasingly cause heat-related symptoms during Summer, but also in Spring and Autumn in some parts of the country [ 30 ].…”

The Incidence of Skin Cancer in Relation to Climate Change in South Africa

“…Currently warming trends (increasing maximum and minimum temperatures) are found in Africa with the ambient temperatures projected to rise faster than the global average increases [43]. Indeed, an increase of 4-6 • C is estimated for Southern Africa by 2071-2100.…”

Gathering the evidence and identifying opportunities for future research in climate, heat and health in South Africa: The role of the South African Medical Research Council

“…for optimal thermal comfort (21 0 C and 24 0 C, respectively). [26,27] Mean indoor summer temperatures also often exceeded 27 0 C; the minimum temperature above which optimal body functioning is detrimentally affected. In schools in the City of Johannesburg, indoor classroom temperatures varied between 21°C at night to 34°C midday during late summer months.…”