Impacts of Heatwaves on Human Health over Burkina Faso

Abstract

Heatwaves have become a serious public health concern around the world in the last few decades. In the Sahel, specifically in Burkina Faso, very little research has been done on heatwaves and their impact on human health. This study comprehensively analyses the impacts of heatwaves on mortality in Burkina Faso, focusing on heatwave characteristics, the Temperature-Humidity Index (THI), and their seasonal and temporal variability. The study used Taylor’s diagram to compare climate model simulations (NASA NEX_GDDP) with observational data from Burkina Faso’s national meteorological agency (ANAM) and ERA5 reanalysis for the past (1991-2021), near future (2020-2050), and the far future (2051-2100). Heatwave characteristics, including amplitude (HWA), frequency (HWF), duration (HWD), magnitude (HWM), and number (HWN), were computed alongside indices such as TN90, TX90, and the Excess Heat Factor (EHF). The trends of heatwave characteristics were analysed with the non-parametric Mann-Kendall test and Sen’s Slope method. The ARIMA Model was used for heatwave and mortality prediction, and the Ensemble Mean (MME) of the NASA NEX-GDDP data was used to project future heatwave characteristics under two Shared Socioeconomic Pathways: SSP2-45 and SSP5-85. The results reveal a north-south gradient in heatwave intensity, with higher values in northern regions. Generally, some models are close to observed in terms of output, while others overestimate the output in all the analysed characteristics. THI showed a weak positive correlation with deaths (R = 0.272, R² = 0.074). The seasonal analysis highlighted strong positive correlations between THI and death (R= 0.5 to 0.6) during the dry months (April, May, and December) and negative correlations (R=-0.2 to -0.7) during the rainy season (August and September), reflecting reduced heat-related risks. While heatwave exhibited a negligible correlation (R2 = 0.018) with mortality, THI was a more significant predictor of mortality (R2 = 0.074). Projections suggest moderate increases in heatwave characteristics by 2050 under both SSPs, with dramatic increases expected by 2100, particularly under SSP585. The frequency, intensity, and duration of heatwaves are anticipated to rise, posing severe health risks for vulnerable populations. Despite weak correlations, adaptive behaviours such as resting during peak heat, improved hydration, and urban initiatives like tree planting may mitigate immediate risks. However, Ouagadougou's rapid urbanisation and infrastructural challenges exacerbate vulnerability, particularly for the elderly, children, and those with pre-existing health conditions. The findings in this study underscore the urgent need for targeted public health interventions during high-risk months (April, May, December), urban planning to mitigate the urban heat island effect, and investments in healthcare infrastructure and early warning systems. The study concluded that addressing climate impacts on health in Burkina Faso and similar regions requires long-term strategies, such as archiving health-related data, expanding vegetation cover, enhancing access to cooling systems, and improving regional adaptation mechanisms. Without significant action, escalating heat stress under climate change will intensify mortality risks, particularly towards the end of this century.