El Niño 80% likely, will trigger extreme temperature and rainfall: UN agency

📌 Summary:

• World Meteorological Organization (WMO) — a UN agency — issued an update "Prepare for El Niño" on June 2, 2026 warning of impending El Niño and rising extreme-weather risk
• Probability of El Niño development during June-August 2026 = 80%; UN Secretary-General Antonio Guterres put the overall certainty at 90% in coming months
• El Niño defined: ocean-atmosphere phenomenon where surface water along equatorial and central Pacific Ocean stays WARMER than usual; influences global temperature and rainfall
• Duration: an El Niño event can last from a few months to up to 2 years; typically peaks in winter months
• Driver: unusually warm subsurface conditions across tropical Pacific — temperatures exceeding 6°C above average provide a substantial reservoir of heat fuelling observed surface warming
• ENSO measurement framework: Relative Oceanic Niño Index (RONI) — sea surface temperature departure from normal over the Niño 3.4 region (5°N-5°S, 120°-170°W); thresholds: 0°C = neutral; > +0.5°C = El Niño; < -0.5°C = La Niña
• Current reading: latest index for Feb-April was -0.5°C; sea surface temperatures during late April to mid-May trending up, confirming El Niño threshold being approached
• Guterres warning: "El Niño conditions will pour fuel on the fire of a warming world" — flagging compounded risk on top of long-term climate change

🎯 UPSC Relevance: GS1 Geography (Climatology, ENSO, ocean-atmosphere interactions, monsoon-El Niño link), GS3 Environment (climate change interactions), GS3 Disaster Management (extreme weather preparedness).

📝 Prelims Facts:

• WMO = World Meteorological Organization (UN specialised agency, HQ Geneva, established 1950)
• El Niño probability for June-August 2026: 80% (WMO)
• ENSO = El Niño-Southern Oscillation
• Niño 3.4 region coordinates: 5°N-5°S, 120°-170°W
• ONI thresholds: > +0.5°C = El Niño; < -0.5°C = La Niña; between = neutral
• Feb-April 2026 index reading: -0.5°C
• Generally El Niño weakens the Indian summer monsoon (correlation, not causation)

🔑 Key Term: ENSO (El Niño-Southern Oscillation) — coupled ocean-atmosphere phenomenon in the tropical Pacific that has three phases (El Niño, La Niña, neutral); its swings drive global climate variability including India's monsoon performance.