A new El Niño yardstick arrives just as food markets tighten

On February 1, 2026, the US National Oceanic and Atmospheric Administration replaced the Oceanic Niño Index with the Relative Oceanic Niño Index as the official metric for El Niño. The new index measures the Pacific against the surrounding tropical ocean instead of a 30-year historical average. A developing Super El Niño and a concurrent positive Indian Ocean Dipole are now raising the risk of extreme weather across the Asia-Pacific.

The methodological shift is a scientific upgrade. It also creates a new uncertainty for governments and food markets that rely on fixed thresholds to trigger drought plans, crop insurance payouts, and food-aid commitments.

The 2026 El Niño is being read as a climate event. The more accurate reading is that the official definition of the climate event was just rewritten. On August 17, Earth Sciences New Zealand reported a 30-day traditional Niño 3.4 value of +4.5°F. The new relative value came in at +3.2°C. The difference between these two measurements is not a measurement error. It is the difference between comparing the ocean to the past and comparing it to the surrounding tropics in a world that is warming everywhere.

This shift sits at the centre of the World Meteorological Organization’s latest seasonal update. The WMO forecasts a strengthening Pacific El Niño alongside a positive Indian Ocean Dipole. The combination is a known amplifier of drought and flood. What is less known is how the new index will interact with the old triggers that countries use to declare emergencies and protect food supplies.

The index swap that changes the threshold

NOAA’s Climate Prediction Center made the switch to the Relative Oceanic Niño Index, or RONI, on February 1, 2026. The agency defines El Niño as RONI readings at or above +0.5°C for five consecutive overlapping three-month seasons. The key difference from the old Oceanic Niño Index is the baseline. ONI uses a fixed 30-year average. RONI uses the mean tropical ocean at the time of the event, measured in degrees Celsius.

Michelle L’Heureux, lead ENSO scientist at NOAA, explained the rationale simply. “RONI compares ENSO to the surrounding tropics, not a lagged climatology,” she said. In practice, this means a 2026 El Niño of a given magnitude registers differently than a 1997 event of the same magnitude. The change is designed to prevent the index from overstating the strength of El Niño in a steadily warming ocean.

For an Indonesian rice importer, the difference between the two indices is not a statistical curiosity. It is the threshold that determines whether a cheaper Thai rice contract gets blocked by a Bangkok export ban. By July 2026, subsurface water in the eastern equatorial Pacific was measured at up to 18°F above average. For a Western reader, this is comparable to raising the entire upper layer of the tropical Pacific by the temperature difference between a mild spring day and a strong summer heatwave, over an area spanning thousands of kilometres—energy sufficient to drive major shifts in global storm tracks and rainfall patterns.

The WMO’s multi-model ensemble shows a rapid strengthening into strong El Niño conditions by the July-to-September window. The International Research Institute for Climate and Society put the probability of an El Niño event at 98% as early as May. The methodological shift is not just a technical footnote. It affects how the US government triggers early-warning protocols for drought and flood risk. A moderate event under the new index could have been a strong event under the old one, and the policy levers tied to those labels are still being recalibrated.

The gap between the two measurement systems is easier seen than read.

Warmer planet, newer rules, same old protectionism

The 2026 El Niño is developing in a climate system that is fundamentally different from the one that produced the major events of 1982 or 1997. Global average temperatures are higher. The atmosphere holds more moisture. The same meteorological strength can produce more extreme rainfall. The WMO’s warning of a concurrent positive Indian Ocean Dipole compounds the risk, as the combination is associated with severe drought across Southeast Asia and Australia.

What makes the coming months particularly dangerous is the overlap between the climate signal and the fragility of global food systems. The 2007-2008 crisis demonstrated that the primary driver of food price spikes is not always the harvest failure itself. It is often the policy response. When countries hoard grain, prices leap. According to the World Meteorological Organization’s Climate Services division, the combination of a strengthening Pacific El Niño and a developing positive Indian Ocean Dipole substantially raises the likelihood of concurrent drought and flood patterns across the Asia-Pacific, stressing the need for early action on food security and disaster preparedness.

The scale of the developing event mirrors the warning signs described in Indoneo’s earlier coverage of the Super El Niño, where the worst impacts were expected to arrive around year-end. The scientific community is now in the uncomfortable position of monitoring a developing crisis with a new yardstick. According to a major 2018 reconstruction, the 1877-78 event, which involved a strong El Niño and Indian Ocean Dipole, is associated with a famine that claimed over 50 million lives. The question is not whether the 2026 event will be severe. It is whether the new measurement system will give governments enough of a clear signal to act before the food trade tightens.

Beyond the headline

The Science Gap

The methodological shift from ONI to RONI reveals how fast the climate baseline is moving: scientists are no longer comfortable judging El Niño against a static past that no longer exists. That raises a deeper question for policy makers—if the yardstick keeps changing, how do they decide when an event is severe enough to trigger drought plans, crop insurance payouts or international food-aid thresholds without relying on outdated historical analogues.

The Timing

This developing El Niño is emerging just as many countries reset post-pandemic fiscal priorities and confront tight budgets for social protection. The overlap between a strong ENSO phase, a possible positive IOD and fragile food-security safety nets means this particular year’s timing could turn what might have been a manageable climate anomaly into a stress test for how quickly governments can adapt their emergency triggers and trade policies to new scientific metrics.

The Reach

One key actor largely outside the headline is the global agricultural finance sector, whose risk models often depend on historical ENSO classifications. As RONI redefines how El Niño strength is recorded, those models may underestimate volatility in regions newly exposed by altered teleconnections, translating into mispriced crop insurance and uneven credit access for farmers—an indirect mechanism by which a Pacific climate oscillation can reshape capital flows into rural economies far from the tropics.

Four groups facing the new El Niño calculus

With the IRI forecasting a 98% probability of El Niño and the WMO warning of a paired IOD, the second half of 2026 arrives with a specific set of risks for four distinct groups.

• Western investor with APAC agricultural commodity exposure

  You need to assess the potential for increased volatility and supply chain disruptions in your portfolio. The 2007-2008 crisis showed that export bans can amplify price spikes by 20-30% in a matter of weeks. Hedging strategies or rebalancing towards less climate-sensitive assets should be reviewed now, before the next WMO update hardens the outlook.

• European or North American food importer/retailer

  Your supply chain resilience is the immediate concern. Evaluate alternative sourcing options for staple goods like rice, vegetable oils, and seafood. The IOD is known to reduce rainfall in Southeast Asia, threatening the main rice harvest. Prepare for potential price increases and supply shortages by locking in contracts with suppliers in less exposed regions, such as South America or West Africa.

• US federal agency climate risk planner

  You must update your internal protocols and models to align with the new RONI index. The switch means that historical El Niño classifications used in drought and flood risk planning need re-evaluation. Early-warning and response strategies tied to the old ONI thresholds will miscalculate the risk of a moderate event under the new system. The NOAA Climate Prediction Center’s technical guidance is the primary source for this recalibration.

• Western NGO worker focused on food security in Southeast Asia

  The combined El Niño and IOD event significantly increases the risk of severe droughts and floods, leading to food shortages in the regions you operate. Prepare for increased demand for aid by pre-positioning resources in vulnerable areas like Indonesia and the Philippines. Adapt program strategies to mitigate the impacts of extreme weather on vulnerable populations and food systems, using the WMO’s seasonal outlook as a planning baseline.

Explainer

ENSO

The El Niño-Southern Oscillation is a climate pattern in the Pacific Ocean. It has three phases: El Niño, La Niña, and neutral. The cycle influences global weather, from rainfall in Southeast Asia to storm tracks in North America.

Indian Ocean Dipole

A climate pattern in the Indian Ocean similar to ENSO. A positive IOD is defined by warmer water in the west and cooler in the east. It tends to cause drought in Southeast Asia and Australia, and floods in East Africa.

RONI

The Relative Oceanic Niño Index compares the Pacific Niño 3.4 region’s sea-surface temperature to the mean tropical ocean. Adopted by NOAA in February 2026, it replaces the old ONI. It is designed to prevent a warming background climate from skewing El Niño strength ratings.

ONI

The Oceanic Niño Index was the standard metric for ENSO from 1982 to 2026. It measured sea-surface temperature anomalies against a fixed 30-year base period. NOAA retired the index because the warming climate made the base period less representative of the current tropical ocean.