Record Pacific Warming and El Niño: Risks for India’s Monsoon and Water Security

What the record establishes—and what it does not

The supplied report states that September sea surface temperatures in Niño 3.4 exceeded the peak absolute temperatures recorded during the strong El Niño episodes of 1982/1983, 1997/1998 and 2015/2016. Copernicus nevertheless cautioned that it could not yet call the current episode the strongest ever recorded.

The distinction is between absolute temperature and the strength of a climate anomaly. A warmer background ocean can lift the absolute temperature reached during El Niño without producing an equivalent increase in the event’s strength relative to that background. Copernicus said its new index, which accounts for tropical ocean warming, did not yet rank the current event above earlier ones.

Japan’s weather agency separately reported its strongest recorded intensity, with temperatures in its monitoring area 4°C above normal. Such assessments should not be treated as interchangeable without checking the monitoring region, reference baseline, averaging period and index used.

• A regional sea surface temperature record is not the same as a record global air temperature.
• Absolute temperature, temperature anomaly and ENSO intensity are related but distinct measures.
• Forecasts of a record-strength peak remain forecasts, not completed observations.

ENSO dynamics: how Pacific warming alters distant rainfall

During El Niño, weakening easterly trade winds allow warm surface water to shift eastward. The thermocline deepens in the eastern equatorial Pacific, reducing the supply of cold water to the surface. Warmer waters shift the main zone of tropical convection, reorganising the Walker circulation.

Ocean warming and atmospheric changes can reinforce one another through the Bjerknes feedback. Changes in tropical heating then influence winds, pressure systems and rainfall beyond the Pacific. ENSO is therefore a coupled circulation phenomenon, not merely a patch of unusually warm seawater.

• El Niño is the warm phase of ENSO; La Niña is its cool phase.
• The Southern Oscillation refers to the associated fluctuation in tropical Pacific atmospheric pressure.
• Teleconnections explain why Pacific conditions can affect rainfall over the Indian subcontinent.
• The recurrence interval is irregular, so ENSO should not be treated as a fixed calendar cycle.

India’s monsoon, agriculture and water security

El Niño is generally associated with a higher risk of deficient Indian summer monsoon rainfall because its circulation changes can favour reduced convection over the Indian region. This is a probabilistic relationship, not a rule: the Indian Ocean Dipole, Indian Ocean conditions and intraseasonal monsoon variability can modify the outcome.

For agriculture, the distribution and timing of rain matter as much as the seasonal total. Delayed sowing, prolonged dry spells and moisture stress during critical crop stages can reduce yields, particularly in rainfed areas. Irrigated farming may face rising pumping costs and competition for water, while heat can add stress to crops and livestock.

By the October edition date, the core southwest monsoon season has largely passed. The report alone cannot establish that this event caused India’s 2026 rainfall outcome, nor can it determine the 2027 monsoon. Future risk assessment must track whether El Niño persists into the relevant season alongside actual rainfall, reservoir storage, soil moisture and groundwater conditions.

• Kharif crops are directly exposed to monsoon rainfall variability.
• Rabi cultivation can be affected through reduced residual soil moisture and irrigation availability.
• Poor recharge can constrain drinking water supplies, irrigation and hydropower generation.
• Food-price pressure is a possible consequence of production losses, not an automatic outcome of El Niño.
• Below-normal seasonal rainfall does not rule out destructive local downpours or floods.

El Niño and climate change: separate drivers, interacting risks

El Niño is a natural source of climate variability; anthropogenic greenhouse gas emissions drive the long-term warming trend. El Niño can temporarily raise global surface temperatures on top of this warmer baseline, increasing the potential for heat stress and other climate impacts.

The report identifies September 2026 as the second-hottest September on record, with global surface air temperature 1.63°C above the 1850–1900 average. A single month above 1.5°C does not, by itself, establish that the Paris Agreement’s long-term temperature goal has been crossed.

The reported possibility of record global temperatures in 2027 is a forecast rather than an observed outcome. The appropriate policy response combines adaptation to near-term climate variability with emissions reduction to limit long-term warming.

• Do not attribute an individual drought, flood or crop loss to El Niño without supporting analysis.
• Do not use short-term ENSO fluctuations to explain away the long-term warming trend.
• Distinguish monthly temperature exceedances from sustained long-term warming.

Preparedness: turn climate outlooks into local decisions

India’s response should be anticipatory and location-specific. India Meteorological Department outlooks need to be combined with agricultural advisories, Central Water Commission reservoir information and state-level assessments of water demand and vulnerability.

Preparedness should cover drought, heat and intense rainfall together. ENSO information can guide seasonal planning, but reservoir operations, crop decisions and emergency measures require regularly updated local observations and forecasts.

• Prepare district contingency crop plans using rainfall, soil moisture and irrigation availability.
• Protect drinking water security through water budgeting, leakage reduction and recharge measures.
• Link heat action plans with health surveillance, worker protection and reliable essential services.
• Use transparent crop and market assessments before changing food-stock or trade policies.
• Communicate forecasts as changing probabilities rather than certain predictions.