Central Asia (CA) experiences large interannual hydroclimate variability that profoundly affects ecosystems, agriculture, and socioeconomic stability. While the El Niño–Southern Oscillation (ENSO) has long been recognized as the leading driver, a significant proportion of observed CA precipitation variability remains unexplained. Here, we reveal that Antarctic ozone variability in October–November serves as a robust and independent precursor to winter CA precipitation (WCAP). Antarctic ozone modulates WCAP through two primary pathways. First, enhanced Antarctic ozone drives a persistent negative phase of the Southern Annular Mode (SAM) that persists into the following winter. The ensuing ozone–SAM coupling shifts two Ferrel cells equatorward and enhances low-level convergence and ascent over CA, thereby increasing WCAP. Second, the negative SAM induces central–eastern South Pacific warming, triggering Rossby wave trains that establish a meridional circulation dipole around CA and strengthen subtropical westerlies, moisture transport, and WCAP. Exposure analyses further indicate that combined ozone–ENSO effects substantially exacerbate precipitation-related socioeconomic risks across CA, adding ~34 billion person-days of population exposure and >34 billion dollar-days of economic exposure by mid-century relative to ENSO alone. Our findings identify Antarctic ozone variability as a critical yet previously underappreciated predictor of CA hydroclimate, revealing subtle interhemispheric connections beyond the traditional ENSO-centric paradigm.
Yao et al. (Mon,) studied this question.