Scientists Warn of Historically Strong El Niño as Record Global Temperatures Loom

In the first week of April 2026, the subsurface temperature anomaly in the top 300 meters of the equatorial Pacific hit +1.6°C — running warmer at this stage than the equivalent point in either the 1997–98 or 2015–16 super El Niño events [1]. By mid-May, the ECMWF probability tracker for El Niño had moved from 22 percent in March to 100 percent, a rate of acceleration faster than anything recorded in the modern satellite era [2]. The question facing climate scientists, governments, and humanitarian agencies is no longer whether El Niño is coming, but how strong it will be — and whether the world is remotely prepared for the answer.

The Numbers: How 2026 Compares to the Record Books

El Niño strength is measured primarily through the Oceanic Niño Index (ONI), the three-month running average of sea-surface temperature (SST) anomalies in the Niño 3.4 region of the equatorial Pacific, spanning 5°N–5°S and 170°W–120°W. An event is classified as El Niño when the ONI exceeds +0.5°C for five consecutive overlapping three-month periods. Events exceeding +1.5°C are considered "strong"; those above +2.0°C are informally termed "super" El Niños [3].

Since 1950, only three events have crossed the super threshold: the 1982–83 event (peak ONI of approximately +2.2°C), the 1997–98 event (+2.4°C), and the 2015–16 event (+2.6°C) [4]. The 2023–24 El Niño peaked at roughly +2.0°C [5].

As of mid-April 2026, the weekly Niño 3.4 index stood at +0.5°C, with the Niño 1+2 region (the far eastern Pacific, closer to South America) already at +1.8°C [1]. Multiple global forecasting systems — ECMWF, NOAA's Climate Forecast System, and Australia's Bureau of Meteorology — have converged on a projected peak anomaly in the Niño 3.4 region of 3°C or above by November 2026 [2][6]. If realized, that would surpass every recorded event and approach or exceed the estimated intensity of the 1877–78 event, which predates modern instrumentation [6].

Source: NOAA CPC / ECMWF

Data as of May 14, 2026CSV

The subsurface data is what alarms researchers most. The Kelvin wave — a pulse of warm water propagating eastward across the Pacific — is running warmer in 2026 than at the equivalent stage of either the 1997–98 or 2015–16 events, and the western tropical Pacific remains above average, indicating additional thermal energy available to fuel the system [2].

Who Gets Hit First: Food Security on the Front Line

El Niño's impacts are not evenly distributed. In southern Africa, the phenomenon typically suppresses rainfall during the October-to-March growing season, when maize — the staple crop for hundreds of millions — is planted and matures. The 2015–16 event triggered the worst drought in the region in 35 years, with maize yields dropping by as much as 50 percent in some countries [7]. For 2026, the FAO and FEWS NET estimate approximately 33 million people in southern Africa are already classified as acutely food-insecure heading into the event [8].

In the Horn of Africa, El Niño typically brings above-average rainfall from October to December, which sounds beneficial but in practice causes flooding, landslides, and displacement that disrupts agriculture and spreads waterborne disease [9]. Roughly 26 million people in the region face acute food insecurity [8].

Southeast Asia faces suppressed monsoon rainfall during El Niño years, reducing rice yields across Indonesia, the Philippines, and Vietnam. An estimated 18 million people in the region are already food-insecure [8][10]. In Central America, the "dry corridor" running through Guatemala, Honduras, and El Salvador sees diminished rainfall that strikes subsistence farming communities hardest, with about 9 million people at risk [8].

Source: FAO / FEWS NET

Data as of May 14, 2026CSV

The compounding factor is that these populations enter this El Niño weakened by the 2023–24 event, which itself followed three consecutive years of La Niña that produced severe drought in the Horn of Africa. The recovery window between events has been shorter than usual, leaving soil moisture depleted and household food reserves thin [10].

The 1.5°C Question: Transient Spike or Permanent Breach?

Carbon Brief's state-of-the-climate analysis estimates that 2026 global mean surface temperature will fall between 1.37°C and 1.58°C above pre-industrial levels, with a best estimate of 1.47°C — likely making it the second-warmest year on record [11]. A roughly 30 percent chance exists that 2026 will exceed 1.5°C above pre-industrial levels for the full calendar year [11].

James Hansen, the former NASA climate scientist now at Columbia University, projects further: he argues that even a moderately strong El Niño will yield a record global temperature in 2026, with 2027 reaching approximately +1.7°C [12]. Hansen attributes this not primarily to El Niño itself but to what he describes as high climate sensitivity and an accelerating net climate forcing [12].

The distinction between a single-year exceedance and a Paris Agreement breach matters. The Paris Agreement's 1.5°C target refers to long-term human-induced warming assessed over 20- to 30-year periods, not individual calendar years [13]. The Copernicus Climate Change Service reported that global warming topped the 1.5°C limit over the last three years in its annual assessment, but climate scientists emphasize this does not constitute a formal breach of the Paris target [13]. A sustained transgression would require at least a decade of consecutive years above the threshold [13].

That said, Inside Climate News has reported that a strong El Niño could "lock Earth into a hotter climate" by redistributing ocean heat in ways that make subsequent cooling less likely [14]. Whether this constitutes a ratchet effect or a transient exceedance remains a subject of active scientific debate.

The Amplification Debate: Climate Change and ENSO

A central question is whether anthropogenic warming is making El Niño events stronger, more frequent, or both. The evidence is mixed, and the scientific community is not of one mind.

A 2025 study published in Nature Communications found that global climate mode resonance is intensifying due to rapidly strengthening ENSO variability, with high-resolution models simulating a transition from moderate-amplitude irregular oscillation to highly regular, intensifying cycles as air-sea feedbacks grow stronger [15]. Another 2025 paper in Nature Communications concluded that the "boost effect" of super El Niño events on climate regime shifts will be "greatly amplified under future greenhouse warming" [16].

A study in the Annals of the New York Academy of Sciences found that current warming has produced "considerable amplification" of ENSO's effects on temperature and precipitation extremes, while also modifying their spatial patterns [17].

However, NOAA's own climate blog has noted that the question "Has climate change already affected ENSO?" lacks a clear affirmative answer [18]. ENSO has operated across a wide range of amplitudes throughout the Holocene, and distinguishing anthropogenic signal from natural multi-decadal variability in a system with only about 70 years of reliable instrumental data remains a genuine challenge. Some researchers argue that claims of climate-change amplification are premature given the limited observational record and the large spread among climate model projections of future ENSO behavior [18].

The honest assessment is that warming appears to be amplifying the impacts of El Niño events — because heat waves are hotter and droughts more severe against a warmer baseline — while the evidence that warming is amplifying the ENSO cycle itself is suggestive but not yet conclusive.

Forecast Failures and the Spring Predictability Barrier

The speed of the 2026 El Niño's development has exposed weaknesses in seasonal forecast models. As recently as February 2026, the consensus forecast from the IRI/CPC plume gave a 70 percent chance of El Niño developing in April–June but offered wide uncertainty about intensity [19]. By May, models had rapidly converged on a much stronger event than initially projected [2].

This is partly a structural problem. ENSO forecasts issued between February and May face the so-called "spring predictability barrier" — a period when the tropical Pacific climate system is naturally noisy and signals are weak, making forecasts less reliable than those issued later in the year [20]. Spring is a transitional time for ENSO, and small perturbations can shift trajectories significantly [20].

A 2025 study in npj Climate and Atmospheric Science found that the dynamical seasonal forecast models in the North American Multi-Model Ensemble are "over-confident for high-confidence El Niño forecasts," meaning that when models express strong agreement on El Niño, the actual outcome is less certain than advertised [21]. The ECMWF's C3S ensemble for September 2026 shows individual member forecasts ranging from +0.2°C to +3.3°C in the Niño 3.4 region — a spread of over 3°C [2].

This matters because governments and humanitarian agencies use these 3–6 month outlooks to pre-position food, activate early-warning systems, and allocate budgets. If the forecasts dramatically underestimate the speed or intensity of onset — as appears to have happened in early 2026 — the lead time for preparedness shrinks. The WMO's Global Seasonal Climate Outlook Briefings feed directly into UN and humanitarian planning cycles, and a compressed warning window means aid arrives later [22].

The Trillion-Dollar Price Tag

The economic consequences of strong El Niño events are staggering and still poorly quantified. A 2023 study in Nature Communications by researchers at Dartmouth College found that the 1997–98 El Niño caused an estimated $5.7 trillion in global economic losses over the following five years, the 1982–83 event cost $4.1 trillion, and the 2015–16 event cost $3.9 trillion [23]. These figures include indirect effects — reduced GDP growth, diminished trade, disrupted supply chains — and far exceed the tens of billions typically cited in contemporaneous damage reports.

Source: Nature Communications / Cambridge University

Data as of May 14, 2026CSV

The same study projected that under future warming scenarios, El Niño–driven economic losses could reach $84 trillion cumulatively by the end of the century [23]. The losses fall disproportionately on tropical countries that contribute least to greenhouse gas emissions.

Against this backdrop, current multilateral preparedness budgets appear thin. UNICEF's 2026 humanitarian appeal covers a broad set of crises but does not specifically allocate for a super El Niño scenario at the scale now projected [24]. The UN's Central Emergency Response Fund (CERF) can release anticipatory funds when scientific thresholds are met, but CERF's total annual budget — roughly $500 million — represents a fraction of the damage that even a moderate El Niño inflicts [25]. The Red Cross network has been updating Early Action Protocols to enable faster funding release, but the gap between preparedness budgets and projected costs remains measured in orders of magnitude [22].

Who Profits From the Warning

El Niño is not merely a humanitarian event — it is a financial one. Commodity traders adjust positions based on ENSO forecasts: El Niño typically drives corn, soybean, and wheat price swings of 5–8 percent as markets price in drought risk in key producing regions [26]. The European Central Bank has noted that financial markets factor in both future price increases and heightened price uncertainty during El Niño, and that incorporating ENSO developments "improves the precision of forecasts on future food commodity price volatility" [27].

Reinsurers and crop insurance companies also recalibrate exposure models. In the United States, drought and high temperatures have been the leading cause of crop insurance indemnity payments in 14 of the past 25 years, averaging 41 percent of total indemnity payouts [28]. A super El Niño would likely trigger higher premiums, benefiting insurers who priced in the risk early.

This creates a structural tension: some of the loudest amplifiers of El Niño severity warnings — commodity research desks, reinsurance analysts, weather-risk hedge funds — have direct financial interests in market volatility. That does not make their analyses wrong, but it does mean that the loudest voices in the information ecosystem are not neutral. Journalists and policymakers should weigh the source when assessing how severity is communicated.

What If the Models Are Wrong?

A significant minority of ensemble model runs still project a weaker event. The ECMWF C3S ensemble includes two systems that consider Niño 3.4 values as low as +0.5°C by late summer — barely El Niño at all [2]. NOAA's CPC assigned an 80 percent probability to ENSO-neutral conditions persisting through April–June 2026, with El Niño emergence only becoming "likely" in the May–July window at 61 percent [29].

If the event stalls or comes in weaker than projected — which has happened before, notably in the false El Niño alarm of 2014 — the outcome would raise uncomfortable questions. The North American Multi-Model Ensemble has a documented tendency toward over-confidence in spring El Niño forecasts, and "confident El Niño forecasts often fail when negative SST anomalies are present in the subtropical northeastern Pacific" [21].

A weaker outcome would not invalidate the forecasts — probabilistic predictions are, by definition, not guarantees. But it would highlight the gap between how scientific bodies communicate uncertainty and how that uncertainty is received by the public and media. Press releases from forecasting centers emphasize central estimates and headline probabilities; the tails of the distribution — where a weaker or stronger event lurks — receive less attention. For policymakers who must decide whether to spend scarce resources on pre-positioning aid, the difference between a 61 percent probability and a 90 percent probability is not academic.

The broader lesson is that ENSO forecasts are not binary predictions. They describe a probability distribution. The responsible use of those forecasts — by journalists, governments, and financial markets — requires engaging with the full range of outcomes, not just the headline.

What Happens Next

The next three months will determine whether 2026 enters the record books alongside 1997–98 and 2015–16 or surpasses them. The subsurface heat loading and the convergence of multiple independent forecasting systems toward a Niño 3.4 anomaly of +3°C provide strong physical evidence for an exceptional event [2][6]. But the spring predictability barrier means that the confidence in these projections is lower than it will be by July.

What is already clear is that the baseline has shifted. Even a moderate El Niño in 2026 would sit atop a warmer ocean, a warmer atmosphere, and a more stressed global food system than any of its predecessors. The amplification may come not from the El Niño itself being stronger, but from the world it arrives in being less resilient.