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Environment & Ecology GS 3 In the news 16 times

El Niño–Southern Oscillation (ENSO)

ENSO is a recurring climate pattern involving fluctuations in sea surface temperatures (SSTs) in the central and eastern tropical Pacific Ocean, coupled with changes in atmospheric pressure (the Southern Oscillation). It cycles between three phases: El Niño (warm), La Niña (cool), and neutral. Each phase typically lasts 9–12 months but can persist for up to 2 years. ENSO is the dominant driver of interannual climate variability on Earth, influencing weather patterns across Asia, the Americas, Africa, and Australia.

Key details
  • El Niño: warming of central/eastern Pacific SSTs by ≥0.5°C relative to average; associated with suppressed monsoon in India.
  • La Niña: cooling of central/eastern Pacific SSTs; generally associated with above-normal monsoon rainfall in India.
  • The Niño3.4 index (SSTs averaged over 5°N–5°S, 120°W–170°W) is the primary monitoring variable.
  • Monitoring agencies: BOM (Australia), NOAA's Climate Prediction Center (USA), IMD (India).
In the news

Tracked since March 03, 2026 · last seen July 06, 2026 · updates as the daily brief publishes

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