Projected impact of increased global warming on heat stress and exposed
population over Africa
Abstract
This study investigates the impact of increased global warming on heat
stress changes and the potential number of people exposed to heat risks
over Africa. For this purpose a heat index has been computed based on an
ensemble-mean of high-resolution regional climate model simulations from
the Coordinated Output for Regional Evaluations (CORE) embedded in the
COordinated Regional Climate Downscaling EXperiment (CORDEX), under two
Representative Concentration Pathways (RCPs) scenarios (RCP2.6 and
RCP8.5), combined with projections of population growth developed based
on the Shared Socioeconomic Pathways (SSPs) scenarios (SSP1 and SSP3).
Results show that by the late 21st century, the increased global warming
is expected to induce a 12-fold increase in the area extent affected by
heat stress of high-risk level. This would result in an increase of
about 10-30% in the number of days with high-risk heat conditions, as
well as about 6-20% in their magnitude throughout the seasonal cycle
over West, Central and North-East Africa. Therefore, and because of the
lack of adaptation and mitigation policies, the exacerbation of ambient
heat conditions could contribute to the exposure of about 2-10 million
person-events to heat stress of high-risk level over Burkina Faso,
Ghana, Niger, and Nigeria. Furthermore, it was found that the
interaction effect between the climate change and population growth
seems to be the most dominant in explaining the total changes in
exposure due to moderate and high heat-related risks over all subregions
of the African continent.