Atlantic Niño is the Atlantic equivalent of El Niño-Southern Oscillation (ENSO), somtimes called ENSO’s little brother. University of Colorado scientists Lei Zhang and Weiqing Han, with support from CPO’s Climate Variability & Predictability (CVP) program, show that the Atlantic Niño can be induced by the Indian Ocean Dipole (IOD). The IOD is the dominant interannual climate variability mode in the tropical Indian Ocean that can operate independently from ENSO. Zhang and Han’s work, published in Nature Communications, uses observational datasets and numerical model experiments to demonstrate how enhanced rainfall in the western tropical Indian Ocean during positive IOD weakens the easterly trade winds over the tropical Atlantic, causing warm anomalies in the central and eastern equatorial Atlantic basin and therefore triggering the Atlantic Niño. Their findings suggest that, despite its relatively small basin size, the Indian Ocean plays a more important role in affecting year-to-year climate variability than previously thought.