El Niño refers to the warming phase of the El Niño–Southern Oscillation (ENSO), an irregular climate cycle involving variations in winds and sea surface temperatures over the tropical Pacific Ocean. Coupled with an atmospheric oscillation called the Southern Oscillation, El Niño events typically recur every two to seven years and last about one year, interspersed with neutral phases or its cooling counterpart, La Niña.

During an El Niño event, sea level air pressure rises higher than normal over Indonesia, Australia, and regions extending across the Indian Ocean. In Southeast Asia, these hotter and drier conditions suppress rainfall, increasing drought severity and creating conditions highly conducive to peatland and forest wildfires.

Stronger iterations, known as Super El Niño events, occur when average tropical Pacific sea surface temperatures rise by 2°C or more. These severe events significantly elevate global climate risks, contributing to intense droughts, extreme temperatures, widespread wildfires, crop failures, and severe ecological and economic disruptions.