Impact of Stratospheric Aerosol Geoengineering on Meteorological Droughts in West Africa
Adéchina Eric Alamou,
Ezéchiel Obada,
Eliézer Iboukoun Biao,
Esdras Babadjidé Josué Zandagba,
Casimir Y. Da-Allada,
Frederic K. Bonou,
Ezinvi Baloïtcha,
Simone Tilmes,
Peter J. Irvine
Affiliations
Adéchina Eric Alamou
Laboratory of Geosciences, Environment and Applications, National University of Sciences Technology, Engineering and Mathematics, Abomey-Calavi BP 2282, Benin
Ezéchiel Obada
Laboratory of Geosciences, Environment and Applications, National University of Sciences Technology, Engineering and Mathematics, Abomey-Calavi BP 2282, Benin
Eliézer Iboukoun Biao
Laboratory of Geosciences, Environment and Applications, National University of Sciences Technology, Engineering and Mathematics, Abomey-Calavi BP 2282, Benin
Esdras Babadjidé Josué Zandagba
Laboratory of Geosciences, Environment and Applications, National University of Sciences Technology, Engineering and Mathematics, Abomey-Calavi BP 2282, Benin
Casimir Y. Da-Allada
Laboratory of Geosciences, Environment and Applications, National University of Sciences Technology, Engineering and Mathematics, Abomey-Calavi BP 2282, Benin
Frederic K. Bonou
International Chair in Mathematical Physics and Applications (ICMPA—UNESCO CHAIR), University of Abomey-Calavi, Abomey-Calavi BP 2549, Benin
Ezinvi Baloïtcha
International Chair in Mathematical Physics and Applications (ICMPA—UNESCO CHAIR), University of Abomey-Calavi, Abomey-Calavi BP 2549, Benin
Simone Tilmes
National Center for Atmospheric Research, Boulder, CO 80305, USA
Peter J. Irvine
Earth Sciences, University College London, London WC1E 6BT, UK
This study assesses changes in meteorological droughts in West Africa under a high greenhouse gas scenario, i.e., a representative concentration pathway 8.5 (RCP8.5), and under a scenario of stratospheric aerosol geoengineering (SAG) deployment. Using simulations from the Geoengineering Large Ensemble (GLENS) project that employed stratospheric sulfate aerosols injection to keep global mean surface temperature, as well as the interhemispheric and equator-to-pole temperature gradients at the 2020 level (present-day climate), we investigated the impact of SAG on meteorological droughts in West Africa. Analysis of the meteorological drought characteristics (number of drought events, drought duration, maximum length of drought events, severity of the greatest drought events and intensity of the greatest drought event) revealed that over the period from 2030–2049 and under GLENS simulations, these drought characteristics decrease in most regions in comparison to the RCP8.5 scenarios. On the contrary, over the period from 2070–2089 and under GLENS simulations, these drought characteristics increase in most regions compared to the results from the RCP8.5 scenarios. Under GLENS, the increase in drought characteristics is due to a decrease in precipitation. The decrease in precipitation is largely driven by weakened monsoon circulation due to the reduce of land–sea thermal contrast in the lower troposphere.
