What Happened
- Australia's Bureau of Meteorology (BOM) has officially declared that the 2025–26 La Niña episode has ended, with the tropical Pacific returning to ENSO-neutral conditions.
- The latest Niño3.4 index reading (week ending March 15, 2026) stood at −0.53°C, well above the La Niña threshold of −0.80°C, confirming the transition.
- International climate models now assign a 62% probability of El Niño developing during June–August 2026 and persisting through the end of the year.
- The neutral phase is expected to dominate through southern autumn (April–May), after which steady oceanic warming is projected to cross El Niño thresholds.
- The forecast carries significant implications for India's Southwest Monsoon (June–September), agricultural output, and food inflation.
Static Topic Bridges
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.
- 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).
Connection to this news: The shift from La Niña to ENSO-neutral and the projected emergence of El Niño by August 2026 signals potential disruption to India's Kharif season monsoon if the El Niño strengthens rapidly, as approximately 60% of El Niño years have resulted in below-normal monsoon rainfall over India.
Indian Ocean Dipole (IOD) and Its Interaction with ENSO
The Indian Ocean Dipole is defined by the difference in sea surface temperatures between the western Indian Ocean (Arabian Sea) and the eastern Indian Ocean (south of Indonesia). A positive IOD — warmer western Indian Ocean — can partially counteract El Niño's suppressive effect on India's monsoon. A negative IOD amplifies El Niño-induced drought conditions. The IOD is a critical secondary variable that IMD weighs alongside ENSO in its long-range monsoon forecasts.
- Positive IOD years: 1983, 1994, 1997 saw above-normal monsoons despite concurrent El Niño.
- The IOD is monitored using the Dipole Mode Index (DMI).
- IOD and ENSO are partially independent but show some co-evolution, especially in September–November.
- India's IMD incorporates 8 predictors — including SSTs over the Niño3.4 region and the IOD — in its Statistical Ensemble Forecast System.
Connection to this news: The eventual impact of the emerging El Niño on the 2026 Southwest Monsoon will be modulated by the concurrent IOD state. A positive IOD developing alongside El Niño could buffer India's agriculture from severe drought.
ENSO and India's Agricultural Economy
India's agriculture, which supports approximately 54% of the workforce and contributes ~17% to GDP, is highly sensitive to ENSO-driven monsoon variability. The Kharif season (June–September), which produces rice, cotton, sugarcane, pulses, and oilseeds, depends almost entirely on the Southwest Monsoon. Drought years triggered by El Niño reduce kharif output, raise food prices, and can tip rural economies into distress. El Niño years have historically coincided with spikes in food inflation and calls for MSP revisions.
- Approximately 60% of El Niño years historically correspond to below-normal monsoon in India.
- Major El Niño-linked drought years for India: 1972, 1982, 1987, 2002, 2009, 2015.
- Food inflation in El Niño years has sometimes exceeded 10–12% year-on-year for cereals.
- The government responds with MSP hikes, buffer stock releases, and import duty adjustments on pulses and oilseeds.
Connection to this news: If El Niño emerges firmly by August 2026 as BOM projects, the risk to the late Kharif season (September harvest) rises. IMD's April long-range monsoon forecast will be closely watched by policymakers, futures markets, and food procurement agencies.
Extreme Weather Events and Climate Change Amplification
Climate change is altering ENSO dynamics by warming baseline ocean temperatures, which potentially intensifies both El Niño and La Niña events when they occur. The IPCC Sixth Assessment Report (AR6, 2021) indicates that ENSO-related precipitation extremes are projected to intensify under global warming, increasing the risk of both floods (during La Niña) and droughts (during El Niño) in South Asia.
- Global mean surface temperature is now ~1.2°C above pre-industrial levels, influencing baseline Pacific SSTs.
- IPCC AR6 projects a 2-fold increase in frequency of extreme El Niño events under 1.5°C warming scenarios.
- Heat waves in El Niño years are more intense due to compounding of background warming with ENSO forcing.
- India's NDC (Nationally Determined Contribution) under Paris Agreement targets net-zero emissions by 2070.
Connection to this news: The 2026 El Niño forecast occurs against the backdrop of near-record global temperatures, meaning its impacts — on India's monsoon, heatwaves, and agricultural output — could be more severe than historical analogues suggest.
Key Facts & Data
- La Niña 2025–26 officially ended as per BOM's March 2026 ENSO Outlook.
- Latest Niño3.4 index: −0.53°C (week ending March 15, 2026); La Niña threshold is −0.80°C.
- El Niño probability for June–August 2026: 62% (international model consensus).
- ENSO-neutral phase expected through April–May 2026 before warming accelerates.
- ~60% of historical El Niño years produce below-normal monsoon rainfall in India.
- India's Southwest Monsoon (June–September) accounts for ~75% of the country's annual rainfall.
- The 2022–23 La Niña was the third consecutive La Niña year — a triple-dip event, the strongest in decades.
- BOM's ENSO Outlook is updated every fortnight; NOAA's ENSO Diagnostic Discussion is monthly.