The World Meteorological Organization issued one of its starkest seasonal advisories in years this week, placing an 80% probability on El Niño forming before September and a 90% chance of it persisting through November. Those are not talking-points numbers — they come directly from the WMO's ensemble of climate models, and they represent a meaningful jump in confidence from earlier in the year. The agency's explicit message to governments: prepare now, not after the first heatwave kills people.

El Niño is a periodic warming of surface waters across the central and eastern tropical Pacific that reshuffles weather patterns across the entire planet. It is not a local event. When sea-surface temperatures in the Niño 3.4 region rise above 0.5°C above the long-term average for long enough, the atmospheric circulation responds — jet streams shift, monsoons weaken or intensify in unexpected places, and the global mean temperature gets an extra push upward. In a strong event, that push can be 0.2 to 0.3°C above the already elevated baseline.

The reason the WMO is using the word "imminent" rather than its usual measured hedging is context. The last three years were dominated by La Niña — El Niño's cool-phase counterpart — which actually suppressed global temperatures somewhat. Despite that suppression, 2023 and 2024 still ranked among the hottest years in the instrumental record. The planet's thermal floor has risen. El Niño does not reset to a 1990s world; it departs from the hottest starting point in recorded history.

For agriculture and food security, the implications are not abstract. El Niño typically disrupts the South Asian monsoon, compresses the growing season across parts of sub-Saharan Africa, and drives drought across Central America and northern South America. The WMO advisory specifically flags elevated risk for regions that are already running food and water deficits. When those regions tip into acute shortage, prices move globally — commodity markets do not stay regional. The WMO has, notably, flagged market risk alongside human risk in its briefing materials, signaling that the economic exposure is being taken seriously at the agency level.

Energy systems face a different but equally concrete threat. El Niño-linked heatwaves crush electricity demand at exactly the moment grid operators in temperate zones are least prepared. The European heat emergencies of recent years unfolded during a relatively neutral or La Niña-influenced period. A full El Niño on top of the warming trend means grid planners in southern Europe, South Asia, and North America's Sun Belt are stress-testing scenarios they have never actually had to survive at scale. The WMO advisory is, implicitly, a procurement and infrastructure signal as much as a meteorological one.

The question of whether this event will become a "super" El Niño — comparable to the record-breaking 1997–98 or 2015–16 events — is not settled by the current data. The WMO is careful on this point: it says a moderate-to-strong event is the central forecast, not a confirmed extreme. But it also notes that even a moderate El Niño layered on top of the current thermal anomaly in the Pacific and the accelerating background warming trend could produce surface temperature records that would have required a strong historic event to reach just a decade ago. The threshold that matters is not the El Niño index in isolation — it is what happens to actual temperatures, droughts, and flood events at the regional level.

Where official messaging tends to go soft is exactly here: governments are told to "prepare," but the mechanisms for what that preparation looks like — pre-positioned food reserves, standby drought emergency protocols, heat mortality reduction plans — are left vague in the public advisory. The WMO does have a formal Early Warnings for All initiative, launched in 2022 with a stated goal of universal coverage by 2027, but implementation is uneven, and the nations most exposed to El Niño impacts are frequently the ones with the least early-warning infrastructure. The advisory is technically sound. The political will to act on it is the variable the agency cannot model.

For the Northern Hemisphere, the critical window is the next 90 days. If the oceanic and atmospheric coupling that locks in El Niño conditions occurs on the WMO's predicted schedule, the second half of 2025 will be unusually active for extreme weather. That is not speculation or worst-case scenario-building — it is the direct implication of the probability figures the WMO has put on record. The time to build resilience is before the pattern establishes, not after the first catastrophic season makes the 80% feel like prophecy.