A new study reveals that the El Niño Southern Oscillation (ENSO), a phenomenon known for its impact on global climate, has been around for at least 250 million years and was more intense in the past than today. Researchers from Duke University used climate models to simulate deep past climate conditions, finding that oscillations were influenced by different land-sea configurations, atmospheric winds, and higher levels of CO2. These findings highlight the importance of understanding past climate patterns for more accurate future projections.