El Niño

El Niño-Southern Oscillation (ENSO) is a global climate phenomenon that emerges from variations in winds and sea surface temperatures over the tropical Pacific Ocean, with El Niño being the warming phase and La Niña the cooling phase. The Southern Oscillation is the accompanying atmospheric oscillation, and the two phenomena last a year or so each, typically occurring every two to seven years with varying intensity. ENSO affects the climate of much of the tropics and subtropics, and has links to higher-latitude regions of the world, disrupting normal weather patterns and leading to intense storms and droughts in different places. ENSO is characterized by a positive feedback mechanism known as the Bjerknes feedback, and its exact mechanisms are unclear and being studied. The relative frequency of El Niño compared to La Niña events can affect global temperature trends on timescales of around ten years, and climate change is expected to exacerbate the effects of droughts and floods.learn more on wikipedia