Influence of Tibetan Plateau Snow Cover on ENSO Variability via the Dust‐Iron Fertilization

Abstract The El Niño–Southern Oscillation (ENSO) and Tibetan Plateau, as key drivers of Earth's climate system, exert bidirectional controls that complicate causal attribution. Here, we integrate satellite‐derived Tibetan Plateau snow cover (TPSC) with causal inference to establish TPSC‐ENSO conversion factor. Using this factor, we estimate that TPSC anomalies contribute 24.8% (6.4%–44.1%) of September ENSO variability. Notably, TPSC‐modulated biogeochemical processes are as influential as equatorial zonal wind mechanisms, constituting an additional ENSO driver. Reduced TPSC intensifies the Tibetan Plateau heat source, driving ascendant easterly anomalies. This accelerates the tropical easterly jet, transporting more Saharan dust to the tropical Pacific. Dust‐iron fertilization stimulates phytoplankton accumulation across iron‐limited central‐eastern Equatorial Pacific, reducing solar irradiance penetration depth, lowering upper ocean heat content by 21% (7%–29%), and promoting La Niña development. Conversely, high TPSC favors El Niño development. These findings quantify TPSC's impact on ENSO variability, unveiling a biogeochemical pathway linking dust‐iron fertilization to ocean energetics.