El Niño is an anomalous warming of the eastern tropical Pacific Ocean that occurs at 2–10 year intervals and is frequently associated with far-reaching climatic and economic impacts around the world. Intensive research following the disastrous 1982–83 event has led to a much greater understanding of the phenomenon and some recent successes in prediction using new, coupled ocean-atmosphere numerical models. The most widely supported hypothesis at present is that El Niño occurs as an internal oscillation of the tropical Pacific Ocean-atmosphere system. While this is not universally adhered to, all agree on one fundamental aspect: that the E1 Niño condition only evolves after an unstable cycle of positive feedbacks between ocean and atmosphere is established along the equator in the central Pacific.

Enfield, D.B. 1988. Is El Niño becoming more common? Oceanography 1(2):23, https://doi.org/10.5670/oceanog.1988.04.

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