Babatunde ABIODUN, University of Cape Town, South Africa
Romaric C ODOULAMI, University of Cape Town, South Africa
Windmanagda SAWADOGO, University of Cape Town, South Africa
Olumuyiwa A. OLONIYO, University of Cape Town, South Africa
Abayomi A. ABATAN, University of Cape Town, South Africa
Christopher LENNARD, University of Cape Town, South Africa
Pinto IZIDINE, University of Cape Town, South Africa
Temitope S. EGBEBIYI1, University of Cape Town, South Africa
Douglas G. MACMARTIN, University of Cape Town, South Africa
Socio-economic activities in Africa depend on the continent’s river basins, but effectively
managing drought risks over the basins in response to climate change is a big challenge. While studies have shown that the stratospheric aerosol injection (SAI) intervention could mitigate temperature-related climate change impacts over Africa, there is a dearth of information on how the SAI intervention could influence drought characteristics and drought risk managements over the river basins. The present study thus examines the potential impacts of climate change and the SAI intervention on drought management over the major river basins in Africa. Multi-ensemble climate simulation datasets were analysed for the study. The Standardized Precipitation Evapotranspiration Index (SPEI) and the Standardized Precipitation Index (SPI) were used to characterize the upper and lower limits of future drought severity, respectively, over the basins. The SPEI is a function of rainfall and potential evapotranspiration, whereas the SPI is only a function of rainfall, so the difference between the two indices is influenced by atmospheric evaporative demand. The results of the study show that, while the SAI intervention may offset the impacts of climate change on temperature and atmospheric evaporative demand, the level of SAI that compensates for temperature change would overcompensate for the impacts on precipitation and therefore impose a climate water balance deficit in the tropics. SAI would narrow the gaps between SPEI and SPI projections over the basins by reducing SPEI drought frequency through reduced temperature and atmospheric evaporative demand while increasing SPI drought frequency through reduced rainfall. This lowers the level of uncertainty regarding future changes in drought frequency, but has implications for future drought management in the basins, because while SAI lowers the upper limit of the future drought stress, it also raises the lower limit of the drought stress.
Mots clés : Climate change|Geoengineering|Droughts|African river basin|drought managment
A104305BA