Probabilistic Analysis of Future Drought Propagation, Persistence, and Spatial Concurrence in Monsoon-Dominant Asian Region under Climate Change

Abstract. This study examines future drought propagation (the temporal transition from meteorological to agricultural droughts), persistence (inter-seasonal droughts), and spatial concurrence (simultaneous occurrence of monsoonal droughts across regions) under climate change using a multivariate copula approach in Monsoon-dominant Asia. Under the worst-case emission scenario (SSP5-8.5), South Asia (excluding Western and Peninsula India) and Eastern China are projected to experience intensified drought propagation compared to the historical period (1975–2014). In addition to increased propagation in these regions, the propagated agricultural droughts are expected to persist across seasons in the future. In terms of the return period, all-season droughts that historically occurred once in more than 50 years could happen as frequently as every five years by the far-future (2061–2100) at the hydrologically significant Tibetan Plateau. Random Forest models indicate that the temperature is a key driver of future agricultural droughts in nearly half of the study area. The spatial concurrence of monsoonal agricultural droughts between region pairs such as South Asia (SAS), East Asia (EAS), Southeast Asia (SEA), and Tibetan region (TIB) was also assessed. Based on bivariate return periods of spatial concurrence, frequent future spatial drought concurrence is anticipated between populous SAS and EAS compared to the historical timeframe, posing risks to water and food security. Conversely, SEA is projected to experience reduced spatial drought concurrence with other regions, which could encourage greater regional cooperation. Overall, this comprehensive approach which integrates three aspects of drought dynamics, offers valuable insights for climate change mitigation, planning, and adaptation.