‘Very’ strong El Nino emerging, to last till Feb 2027: WMO

Physical Geography & Climatology · 4 September 2026 · Based on Indian Express (original report)

Worth reading — 1 past UPSC question on this theme (Prelims GS-1 2017).

2-minute summary

The World Meteorological Organization (WMO) has issued a warning regarding the emergence of a "very strong" El Niño event, which is projected to persist until February 2027. This natural ocean-atmosphere phenomenon, characterized by the significant warming of the equatorial Pacific Ocean, is already disrupting global weather patterns, causing extreme heatwaves, droughts, and floods. The intensity of this event is marked by sea surface temperature anomalies in the Nino 3.4 region, which surpassed the 2 degrees Celsius threshold above normal in July 2026. For India, while the southwest monsoon largely escaped the developing El Niño due to its late-stage intensification, the phenomenon is expected to keep winter temperatures warmer than usual. However, the potential development of a positive Indian Ocean Dipole (IOD) during autumn could act as a countervailing force, mitigating some of El Niño's adverse impacts on the region's weather systems.

Why it's in the news

The World Meteorological Organization (WMO) has officially warned of an intensifying, 'very strong' El Niño event that is expected to last until February 2027, threatening to trigger severe global weather anomalies and economic disruptions.

Background and context

The El Niño-Southern Oscillation (ENSO) is a major climate driver involving fluctuating ocean temperatures in the equatorial Pacific. El Niño represents the warm phase, where weakened trade winds allow warm water to pile up in the central and eastern Pacific, shifting atmospheric convection eastward. This typically suppresses the Indian Southwest Monsoon and causes warmer winters in northern India. Conversely, the Indian Ocean Dipole (IOD) is a similar ocean-atmosphere interaction in the Indian Ocean. A 'positive IOD' occurs when the western Indian Ocean (near Africa) is warmer than the eastern part (near Indonesia). This positive phase enhances rainfall over India and can successfully counter the drying effects of a concurrent El Niño, as observed historically in 1997 and 2019. The Nino 3.4 region (5°N-5°S, 120°W-170°W) is the standard zone used by meteorologists to measure these sea surface temperature anomalies.

Committees and reports

• WMO El Niño/La Niña Update — Provides global scientific consensus and forecasts on ENSO phases, helping nations prepare for extreme weather events and manage agricultural risks.

Government schemes

• National Monsoon Mission — Aims to build a state-of-the-art dynamical prediction system for better forecasting of monsoons, seasonal rainfall, and extreme weather events like El Niño.
• Pradhan Mantri Fasal Bima Yojana (PMFBY) — Provides comprehensive crop insurance cover against non-preventable natural risks, crucial for farmers facing El Niño-induced droughts or erratic rainfall.

International organisations

• World Meteorological Organization (WMO) — A specialized agency of the United Nations established in 1950, headquartered in Geneva, Switzerland. It is the UN system's authoritative voice on the state and behavior of the Earth's atmosphere, its interaction with the land and oceans, the weather, and climate.

Previous UPSC questions on this theme

• Prelims GS-1 2017 — With reference to 'Indian Ocean Dipole (IOD)' sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct? 1. IOD phenomenon is characterised by a difference in sea surface temperature between tropical Western Indian Ocean and tropical Eastern Pacific Ocean. 2. An IOD phenomenon can influence an El Nino's impact on the monsoon. (a) 1 only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2

Mains practice: What is the Indian Ocean Dipole (IOD)? Discuss how a positive IOD phase can act as a countervailing force against the adverse effects of a strong El Niño on the Indian monsoon.

The Indian Ocean Dipole (IOD), often referred to as the 'Indian Niño', is an ocean-atmosphere coupled phenomenon in the tropical Indian Ocean. It is defined by the difference in sea surface temperature (SST) anomalies between the western tropical Indian Ocean (near Africa) and the eastern tropical Indian Ocean (near Indonesia).

During a positive IOD phase, the western Indian Ocean becomes unusually warm, while the eastern Indian Ocean cools. This temperature gradient alters atmospheric circulation, acting as a crucial countervailing force against El Niño in the following ways:

• Enhanced Convective Activity: The warming of the western Indian Ocean enhances convection and cloud formation over the Arabian Sea. This directs moisture-laden winds toward the Indian subcontinent, boosting monsoon rainfall.

• Overcoming Pacific Subsidence: El Niño typically creates a descending limb of the Walker Circulation over South Asia, which suppresses rainfall. A positive IOD creates a strong localized ascending limb over the western Indian Ocean, countering this subsidence and sustaining monsoon activity.

• Historical Precedents: In historical years like 1997 and 2019, India experienced normal to above-normal rainfall despite facing strong El Niño conditions, primarily due to the development of highly intense positive IOD episodes.

In conclusion, while El Niño poses a severe threat to India's rain-fed agriculture and water reservoirs, a positive IOD serves as a vital atmospheric buffer. Strengthening dynamical forecasting models under India's National Monsoon Mission is essential to accurately predict these interacting ocean-atmosphere phenomena and ensure robust agricultural planning.

Prelims practice questions

Q1. With reference to the El Niño Southern Oscillation (ENSO), consider the following statements: 1. The Nino 3.4 region, located in the equatorial Indian Ocean, is the primary zone used to measure sea surface temperature anomalies. 2. During an El Niño event, trade winds along the equator weaken, allowing warm water to move eastward toward South America. 3. El Niño events typically lead to colder-than-normal winter temperatures across northern India. Which of the statements given above is/are correct?

1. 2 only
2. 1 and 2 only
3. 2 and 3 only
4. 1, 2 and 3

Answer: A. Statement 1 is incorrect because the Nino 3.4 region is located in the equatorial Pacific Ocean, not the Indian Ocean. Statement 2 is correct; weakened trade winds allow warm surface water to accumulate in the central and eastern Pacific. Statement 3 is incorrect because El Niño is associated with warmer-than-normal (milder) winter temperatures in northern India, keeping the cold at bay.

Q2. Which of the following best describes the conditions during a 'Positive Phase' of the Indian Ocean Dipole (IOD)?

1. Warmer than normal sea surface temperatures in the western tropical Indian Ocean and cooler than normal temperatures in the eastern tropical Indian Ocean.
2. Significant cooling of the entire Indian Ocean basin coupled with intense trade winds.
3. Warmer than normal sea surface temperatures in the eastern tropical Indian Ocean and cooler than normal temperatures in the western tropical Indian Ocean.
4. Uniform warming across both the western and eastern basins of the tropical Indian Ocean.

Answer: A. A positive IOD is characterized by warmer-than-normal sea surface temperatures in the western tropical Indian Ocean (western Indian Ocean/Arabian Sea) and cooler-than-normal temperatures in the eastern tropical Indian Ocean (near Indonesia).

Q3. Consider the following statements regarding the World Meteorological Organization (WMO): 1. It is a specialized agency of the United Nations. 2. It is headquartered in Geneva, Switzerland. 3. India is not a member of the WMO. Which of the statements given above are correct?

1. 1 and 3 only
2. 2 and 3 only
3. 1 and 2 only
4. 1, 2 and 3

Answer: C. Statements 1 and 2 are correct. The WMO is a specialized agency of the UN headquartered in Geneva, Switzerland. Statement 3 is incorrect because India is a founding/active member of the WMO.

Revision flashcards

• What is El Niño? A climate pattern characterized by the unusual warming of surface waters in the eastern and central equatorial Pacific Ocean, disrupting global weather.
• Where is the Nino 3.4 region located and why is it important? It is located along the equatorial Pacific Ocean (5°N-5°S, 120°W-170°W). It is the standard region used to determine the intensity of ENSO phases based on sea surface temperature anomalies.
• How does a positive Indian Ocean Dipole (IOD) affect the Indian Monsoon? It enhances the monsoon by warming the western Indian Ocean, increasing convection and moisture transport toward India, often countering El Niño's drying effects.
• What is the typical impact of El Niño on Indian winters? It generally leads to warmer-than-average winter temperatures, keeping extreme cold conditions at bay.
• What is the status and headquarters of the WMO? It is a specialized agency of the United Nations for meteorology, operational hydrology, and geophysics, headquartered in Geneva, Switzerland.