Emergence of new heat stress hotspots over West Africa
Abstract
Motivated by the recent record-breaking heatwaves over western Africa, we analyzed 50 years of hourly wet-bulb globe temperature (WBGT) data to identify emerging heatwave hotspots, characterize their timing and types, and evaluate whether simpler heatwave metrics, more commonly used by meteorological agencies, can be employed to estimate dangerous WBGT conditions. We find that exposure to WBGT ≥30 °C and <33 °C (conditions dangerous during light physical activity) has been increasing across almost all of western Africa, at rates of 30–100 h per decade. We highlight two major heat stress hotspots: the border region of Senegal, Mauritania, and Mali, and southwestern Niger, where the WBGT threshold of 33 °C (dangerous even at rest) has recently been exceeded for up to 40 h per year, increasing by 1–4 h per decade. These regions experience dangerous heat stress conditions as a consequence of high temperatures in the late spring, and moderately high temperatures and high humidities in early autumn. Current extreme heat monitoring operates from April to June, while our analysis suggests that it should be extended to also include September and October, when high humidity makes dangerous conditions possible at lower air temperatures. Moreover, because episodes of dangerous heat stress can occur over a wide range of temperatures, relying solely on high temperature percentiles would have missed over 60% of dangerous WBGT episodes across most of the region. Employing the extreme heat indicators that also account for humidity is thus essential.
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BibTeX
@article{cvijanovic2026emergence,
title = {{Emergence of new heat stress hotspots over West Africa}},
author = {Ivana Cvijanovic and Benjamin Sultan and Asse Mbengue and Martha Vogel and Ousmane Ndiaye and Christophe Lavaysse},
journal = {npj Natural Hazards},
year = {2026},
month = jul,
doi = {10.1038/s44304-026-00240-5},
url = {https://hal.science/hal-05752182v1},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Emergence of new heat stress hotspots over West Africa
AU - Ivana Cvijanovic
AU - Benjamin Sultan
AU - Asse Mbengue
AU - Martha Vogel
AU - Ousmane Ndiaye
AU - Christophe Lavaysse
PY - 2026
DA - 2026/07/09
JO - npj Natural Hazards
DO - 10.1038/s44304-026-00240-5
UR - https://hal.science/hal-05752182v1
AB - Motivated by the recent record-breaking heatwaves over western Africa, we analyzed 50 years of hourly wet-bulb globe temperature (WBGT) data to identify emerging heatwave hotspots, characterize their timing and types, and evaluate whether simpler heatwave metrics, more commonly used by meteorological agencies, can be employed to estimate dangerous WBGT conditions. We find that exposure to WBGT ≥30 °C and <33 °C (conditions dangerous during light physical activity) has been increasing across almost all of western Africa, at rates of 30–100 h per decade. We highlight two major heat stress hotspots: the border region of Senegal, Mauritania, and Mali, and southwestern Niger, where the WBGT threshold of 33 °C (dangerous even at rest) has recently been exceeded for up to 40 h per year, increasing by 1–4 h per decade. These regions experience dangerous heat stress conditions as a consequence of high temperatures in the late spring, and moderately high temperatures and high humidities in early autumn. Current extreme heat monitoring operates from April to June, while our analysis suggests that it should be extended to also include September and October, when high humidity makes dangerous conditions possible at lower air temperatures. Moreover, because episodes of dangerous heat stress can occur over a wide range of temperatures, relying solely on high temperature percentiles would have missed over 60% of dangerous WBGT episodes across most of the region. Employing the extreme heat indicators that also account for humidity is thus essential.
SN - 2948-2100
ER -