El Niño Returns: Why Scientists Fear a Big, Costly Event and What It Means for India’s Monsoon

Why in News?

The US National Oceanic and Atmospheric Administration (NOAA) confirmed on June 11, 2026 that El Niño conditions have developed in the equatorial Pacific and issued a formal El Niño Advisory.

The development matters because it stacks a likely “big, bad and costly” El Niño on top of an already below-normal Indian monsoon forecast. The concrete specifics:

• NOAA’s Climate Prediction Center put a 63% chance that the event becomes intense enough by late fall–early winter to rank among the largest El Niños since 1950.
• Forecasters flagged an unusual feature: this El Niño could peak one to two months earlier than the typical late-autumn-to-winter maximum.
• WMO update (June 2, 2026): 80% likelihood of El Niño during June–August, rising to about 90% through November.
• Weekly sea-surface temperatures in the Niño 3.4 region crossed the +0.5°C anomaly threshold that defines the phenomenon.
• IMD has already cut its southwest monsoon forecast to 90% of the long-period average (LPA) — firmly “below normal”.
• Monsoon arrived over Kerala on June 4, 2026, three days behind the normal onset date of June 1.

UPSC Relevance

Prelims Relevance

• El Niño = warm phase of the El Niño–Southern Oscillation (ENSO); anomalous warming of central-eastern equatorial Pacific.
• Niño 3.4 region: 5°N–5°S, 170°W–120°W; tracked by the Oceanic Niño Index (ONI).
• Declaration threshold: SST anomaly of +0.5°C or more; “very strong” event = ONI of +2.0°C or above (1982–83, 1997–98, 2015–16).
• Southern Oscillation Index (SOI): surface-pressure see-saw between Tahiti and Darwin; strongly negative SOI signals El Niño.
• Bjerknes feedback: warmer eastern Pacific weakens trade winds, warming the east further.
• Walker circulation: rising air over warm west Pacific, sinking air over cool east; weakens/shifts during El Niño.
• Indian Ocean Dipole (IOD): a positive IOD can offset El Niño’s monsoon impact; IMD expects neutral IOD in 2026.
• IMD LPA for southwest monsoon = 87 cm (1971–2020 average); “normal” = 96–104% of LPA, “deficient” = below 90%.
• El Niño recurs every 2–7 years, lasts about 9–12 months, peaks November–February.

Mains Relevance

GS Paper 1 (Geography — physical and climatology):

• ENSO is the most frequently tested ocean-atmosphere interaction — Walker circulation, thermocline behaviour, teleconnections, monsoon variability.
• El Niño–monsoon link and the modulating role of the IOD.

GS Paper 3 (Economy, agriculture and disaster management):

• A 90%-of-LPA monsoon under El Niño threatens kharif output, food inflation and rural demand.
• El Niño years compress drought, heat-wave and wildfire risk into one season — testing the Drought Manual 2016, district contingency crop plans and heat action plans.

Essay

• Natural climate variability riding on an anthropogenic warming trend; “preparation, not panic” as the governable variable.

Background and Context

ENSO Mechanics and the Warm Phase

El Niño is the warm phase of the coupled ocean–atmosphere ENSO cycle of the tropical Pacific.

• In the neutral state, trade winds blow east to west, piling warm water near Indonesia and pulling cold, nutrient-rich water up the South American coast.
• During El Niño, trade winds weaken, the warm pool sloshes eastward, the thermocline flattens, and the Walker cell weakens or shifts.
• The Bjerknes feedback amplifies the change in a self-reinforcing loop.
• Strength scale on ONI: weak (+0.5 to +0.9°C), moderate (+1.0 to +1.4°C), strong (+1.5 to +1.9°C), very strong (+2.0°C or more).
• See the full El Niño explainer for mechanics, indices and teleconnections.

The India–Monsoon Connection

El Niño tilts the southwest monsoon toward deficit — but the link is probabilistic, not mechanical.

• A displaced Walker circulation parks subsiding, rain-suppressing air over the Indian region during June–September.
• Droughts of 2002, 2009 and 2015 were all El Niño years (2015 ended at 86% of LPA).
• Yet 1997–98, the strongest El Niño of the twentieth century, coexisted with a slightly above-normal 102% monsoon.
• 2023 El Niño produced about 94% of LPA with the driest August since 1901 — but a positive IOD cushioned the blow.
• A positive Indian Ocean Dipole can offset part of the Pacific signal — the cushion India may lack in 2026.
• Revise the monsoon’s full mechanism and the LPA framework alongside this note.

IMD 2026 Forecasts

IMD’s two-stage 2026 forecasts already carry the El Niño imprint.

• First-stage forecast (April 13): seasonal rainfall at 92% of LPA (±5%); deficient-season probability raised to 35% against a 16% norm.
• Second-stage update (late May): headline cut to 90% of LPA (±4%); monsoon core zone below 94% of LPA; June rainfall pegged at 92% of average.
• IMD expects a neutral IOD this season, removing the counterweight that softened 2023.
• See IMD lowers monsoon forecast, raises spectre of drought.

The Four Transmission Channels to India’s Economy

A Pacific anomaly becomes an Indian budget problem through four channels.

• Agriculture: just over half of India’s net sown area lacks assured irrigation; kharif crops (paddy, pulses, oilseeds, coarse cereals, cotton) drink directly from monsoon rain.
• Prices: food and beverages carry close to half the weight in the CPI, so a poor harvest moves headline inflation within months.
• Water and energy: a weak monsoon leaves reservoirs low for rabi and cuts hydropower just as heat-driven electricity demand rises.
• Rural incomes: failed sowing shrinks farm wages and rural consumption, moving tractor and consumer-goods demand.

Global Signature and Costs

• Western South America: torrential rain and floods; Australia: drought, heat and wildfire; northeastern Africa: weather whiplash.
• Atlantic hurricane season typically suppressed; Pacific cyclone season more active.
• A 2023 study in Science (Callahan and Mankin) attributed $4.1 trillion and $5.7 trillion in lost global income to the 1982–83 and 1997–98 El Niños respectively, with growth depressed for years.
• Same study projected El Niño-linked losses could reach $84 trillion over the twenty-first century.
• India’s exposure is first-order: agriculture employs about 45% of the workforce.
• El Niño’s global temperature effect is strongest the year after development — scientists expect 2027 to challenge the record for hottest year measured.

The Policy Toolkit Already Exists

• Price-defence playbook from 2023–24: rice export restrictions, wheat stock limits, duty-free pulses imports, onion export duties, open-market grain sales.
• Anticipatory supply-side tools: district agriculture contingency plans for 650+ districts, seed minikits for short-duration and drought-tolerant varieties, fodder banks, staggered MGNREGA works.
• Trade-off: export curbs protect consumers but cut farmer realisations and dent India’s reliability as a food exporter.
• The monetary side is harder: the RBI must weigh a food-price shock against a growth cycle it does not want to choke.

Challenges and Concerns

• Forecast uncertainty: ENSO models cross the “spring predictability barrier” with wide error bars; seasonal forecasts have missed badly (2002, 2004).
• The El Niño–monsoon link is probabilistic — 1997 paired the century’s strongest El Niño with a 102% monsoon while moderate 2002 delivered a devastating drought.
• Price-stabilisation tools carry trade-offs that transfer cost to farmers and erode India’s standing as a grain exporter.
• Drought response remains largely reactive; states criticise the Drought Manual 2016’s tightened criteria for making central assistance harder to access.
• Compound-event readiness is thin: simultaneous heat waves, low hydropower, urban water stress and crop failure strain administrative bandwidth.

Way Forward

Spend the Five-Month Runway

• Activate district agriculture contingency plans now.
• Pre-position short-duration and drought-tolerant seed varieties.
• Build fodder and water budgets before reservoirs run down.
• Expand crop-insurance enrolment ahead of sowing, not after failure.
• Keep MGNREGA ready to absorb a rural employment shock.
• Announce trade interventions early and calibrated, not in panic.

Institutional Upgrades

• Extend IMD’s block-level forecasting to drought-prone districts.
• Harden heat action plans before a likely scorching 2027.
• Write compound-event protocols assuming drought, heat and power stress arrive together.

Conclusion

El Niño loads the dice toward a weak monsoon, food inflation and rural distress, but it does not roll them. The Pacific anomaly becomes an Indian macroeconomic event only if a deficit monsoon meets weak preparation.

Early declaration is an asset: NOAA and the WMO have handed governments roughly a five-month runway before the likely peak. The deciding variable between a hazard and a disaster is governance.

For India that means treating the IMD forecast as an action trigger, not a talking point — because El Niño is predictable enough that most of its damage is a choice.

UPSC Practice Questions

Prelims MCQ 1

Consider the following statements regarding El Niño and the El Niño–Southern Oscillation (ENSO):

1. El Niño is declared when the sea-surface temperature anomaly in the Niño 3.4 region holds at or above +0.5°C on the Oceanic Niño Index.
2. A strongly positive Southern Oscillation Index (SOI) signals an El Niño event.
3. A positive Indian Ocean Dipole can offset part of El Niño’s weakening effect on the southwest monsoon.

How many of the above statements are correct?

(a) Only one (b) Only two (c) All three (d) None

Answer: (b)

Explanation:

• Statements 1 and 3 are correct.
• Statement 2 is wrong: a strongly negative (not positive) SOI signals El Niño, since pressure falls at Tahiti relative to Darwin.

Prelims MCQ 2

With reference to the India Meteorological Department’s monsoon classification, the long-period average (LPA) for the southwest monsoon is taken as 87 cm. A season is classified as “deficient” when rainfall is:

(a) below 90% of the LPA (b) between 90% and 96% of the LPA (c) between 96% and 104% of the LPA (d) above 110% of the LPA

Answer: (a)

A season is “deficient” below 90% of LPA and “normal” between 96% and 104% of LPA. IMD’s 2026 second-stage forecast of 90% of LPA sits in the below-normal band.

UPSC Mains Questions

“El Niño is a necessary caution but not a sufficient cause for Indian monsoon failure.” Explain the ocean-atmosphere mechanics of ENSO and examine the factors that modulate its impact on the southwest monsoon. (GS1, 15 marks)

With the IMD forecasting a below-normal monsoon amid a strengthening El Niño, trace the transmission channels from a rainfall deficit to food inflation and rural distress, and critically evaluate the policy instruments available to break this chain. (GS3, 15 marks)