Climate Change Alters Soil Moisture Control on Meteorological Drought Across Africa

Drought in Africa is typically understood as atmospheric-driven phenomenon, yet the role of soil moisture deficits in triggering subsequent meteorological drought remains poorly understood. Here, we show that soil moisture exerts a temporally structured and regionally heterogeneous control over meteorological drought across Africa. Using observation-and CMIP6 model-derived Standardized Soil Moisture Index (SSMI) and Standardized Precipitation Evapotranspiration Index (SPEI), we reveal that soil moisture exerts the strongest influence on meteorological drought at lags of 10 to 11 months. We demonstrate that meteorological drought under soil moisture deficit is most likely in transitional climate zones, with probabilities of 0.59 in West Africa and 0.59 in southern Africa, and least likely in ocean-dominated East Africa, with a probability of 0.36. Under future climate scenarios, the predictive influence of soil moisture weakens substantially, with the continental-scale 11-month influence decreasing by 28%. These changes are consistent across different climate projections, indicating thermodynamic inevitability. Our findings challenge the unidirectional drought-cascade paradigm and demonstrate that climate change is fundamentally reorganizing soil moisture-based predictability of meteorological drought, which has critical implications for African drought forecasting and adaptation.