The response of African monsoons to the symmetric and asymmetric Volcanic eruptions in past and future climate

The release of stratospheric aerosols from major volcanic eruptions induces large-scale global and regional climate impacts through radiative perturbations. The extent of these impacts depends on the season, aerosol-cloud distribution, the height reached by the ejections, and the latitude of the eruption, causing symmetrical and asymmetrical forcing. Previous studies have linked some severe Sahel drought conditions during the 20th century from two to four seasons of post-eruption feedback. However, a detailed analysis of the causal mechanism through the complex teleconnections driving changes of the African monsoon and its atmospheric dynamics in response to the volcanic eruption is yet to be addressed. Besides, the interest in the deliberate stratospheric injection of sulfate aerosols as a Solar Radiation Management (SRM) technique has increased due to the difficulties of limiting the global mean temperature to 1.5 or 2.0 °C above the Pre-industrial level. This implies the need to investigate the associated hydro-climate changes in response to such climate change solution techniques across Africa. In this study, we explore the response of the African monsoon and its driving teleconnections changes to past volcanic eruptions to better understand the potential climate impacts of future eruptions and even further to the proposed SRM geoengineering. Since larger and wider varieties of eruptions occurred in the last millennium compared to the 20th century, we use the past millennium's natural external volcanic forcings as an analog to explore the dynamics feature and associated teleconnections of the African monsoon. We rely on the varied experimental simulation outputs of the state-of-the-art Earth System Models that participated in the sixth phase of the Coupled Model Intercomparison Project (CMIP6). More specifically, we use the models that simulated the past millennium (PMIP4; Jungclaus et al., 2017), volcanic forcing experiments (VolMIP; Zanchettin et al., 2016), and stratospheric aerosol geoengineering experiments (GEOMIP; Jones et al., 2021). Overall, the analyzed responses from the modelling perspective provide an overview of the impact of volcanic forcings across Africa in the past, present, and future climates.