Weakened Variability of Afro‐Asian Monsoonal Precipitation in Response to a Past Warm‐Cold Transition

The Afro‐Asian monsoon domain faces a “wetter and more variable” paradigm under future warming, but whether a “drier and less variable” hydroclimate emerges under cooling remains unconstrained. Using a ∼1° transient global climate simulation during the Last Interglacial (130–115 ka) covering the precession‐induced warm‐cold transition, we demonstrate a general weakening trend of precipitation variability over the Afro‐Asian monsoon domain except for southern India at multiple timescales, but with divergent dynamical mechanisms. Precipitation variability changes are dynamically dominated by the vertical motion variability over the Asian monsoon domain associated with diabatic heating, while thermodynamically controlled by cooling‐induced reduced atmospheric moisture over West Africa. Furthermore, we found no fixed relationship between changes in mean precipitation and its variability across the Afro‐Asian monsoon zone during the warm‐cold transition due to their distinct driving mechanisms, contrasting to the uniformly thermodynamic‐driven variability in greenhouse gas‐induced warmer world. Despite the discrepant external forcings between the seasonally/latitudinal‐dependent Earth's orbit across the Last Interglacial and the uniform year‐round greenhouse‐gas, our findings reveal how precipitation variability responses under contrasting climate states. These results offer insights into how gradual long‐term orbital forcing regulate short‐term precipitation variability.