The major year-to-year climate signal on Earth is the El Nio–Southern Oscillation (ENSO) cycle, which alternates warm El Nio and cold La Nia occurrences. ENSO is caused by interactions between the ocean and the atmosphere in the tropical Pacific, but its environmental and social effects are seen all over the world. With the intense El Nio of 1997–1998 as a catalyst, research into the origins and repercussions of ENSO has exploded in recent years. These initiatives demonstrate the range of ENS-O’s effect on the Earth system, as well as the potential for social benefit from its forecasting. Many interconnected problems about ENSO dynamics, effects, predictions, and applications, on the other hand, remain unsolved Research into these challenges will not only advance a wide range of scientific fields, but it will also give a chance to educate the general public and policymakers on the relevance of climate variability and change in the modern world.
