The Pacific is warming faster than at any point in history, and central bankers have started writing it into their forecasts. A super El Niño now under way began in June and is expected to run into 2027. Carbon Brief analysis of forecasts from 14 modelling groups finds that 96% of runs predict the strongest event in the observational record, with peak sea-surface temperatures in the central Pacific exceeding the 2.75°C anomaly set in 2015-16.

The finding comes from an explainer on the super El Niño published by Carbon Brief on August 18, written by Robert McSweeney and Daisy Dunne.

On the same day, the European Central Bank's chief economist Philip Lane told Irish radio that “food inflation is going to be one of the drivers of inflation over next year”, naming El Niño among the pressures he expects to build through 2027.

For emerging markets, a warming pattern in a stretch of ocean most of them do not border is about to reorganise their harvests, their hydropower, their shipping lanes and their central bank meetings.

How the machine works

In a normal year, trade winds blow east to west across the tropical Pacific, pushing warm surface water towards Asia and drawing cold, nutrient-rich water up off the South American coast. That upwelling is why Peru has the largest anchovy fishery in the world by volume.

The temperature contrast sets the rainfall. Warm water in the western Pacific fuels heavy rain over Indonesia and southeast Asia; cold water in the east suppresses it along South America's west coast.

During an El Niño the trade winds weaken or locally reverse. Warm water spreads back east, upwelling stops, the temperature contrast collapses, the pressure gradient weakens - which weakens the winds further. It is a feedback loop, which is why these events amplify once started.

Scientists track it through the Niño3.4 region, a rectangle of the central Pacific covering more than 6mn sq km. Sustained readings of at least 0.5C above average on the Oceanic Niño Index mean El Niño conditions; -0.5C means La Niña is possible. The US National Oceanic and Atmospheric Administration requires those conditions to persist across five consecutive overlapping three-month periods, and also looks at wind and rainfall. In 2026 it switched to a relative index that strips out the background warming of the tropical Pacific itself.

Peruvian fishermen were the first to name it, some time before the 1600s, for the warm current that arrived around Christmas: El Niño de Navidad, the Christ Child. Gilbert Walker coined “Southern Oscillation” for the pressure seesaw in 1926; Jacob Bjerknes joined the two halves together in the 1960s.

Where the rain moves

The redistribution of rainfall is roughly predictable and very brutal. In northern and tropical South America - Colombia, Venezuela, northern Brazil - El Niño brings heat and drought, and with them wildfire. In the south, southern Brazil, central Chile and northern Argentina, it brings severe flooding.

Southeast Asia and much of Australia dry out, raising drought and fire risk across the palm oil, rice and coal-producing belt.

India gets extreme heat early in the year and a weakened summer monsoon later, which is the single most consequential rainfall system on earth for food prices. China and Japan tend to run warm at the start of the year.

In Africa, southern countries face drought risk from December to February while eastern ones face floods - the same event, opposite problems, on either side of the continent. In North America, the northwest gets a mild winter and the southern US and California get storms and flooding.

Storms change address

El Niño does not create more tropical storms so much as move them. In the Atlantic and Caribbean it increases vertical wind shear, which tears developing systems apart - so hurricane seasons tend to be quieter.

In the Pacific the storm-formation zone shifts east with the warm water. Typhoons become less likely to track towards the Philippines and more likely to hit Taiwan, China, Japan and South Korea. Because they form further out, they have longer over open water to gather heat and moisture, which makes the ones that do make landfall bigger.

For central and eastern Pacific islands - Hawaii, Kiribati, Tuvalu - warmer water means more storms and stronger ones.

The price of weather

The economic transmission is already visible before the event has peaked. UBS has warned that a strong El Niño threatens Latin American inflation and the region's rate-cutting cycle, which is the difference between a soft landing and a stalled one for several central banks.

Shipping is exposed through fresh water rather than sea water: the Panama Canal runs on rainfall, and El Niño threatens to derail its transit recovery just as volumes had come back.

It lands on a food system already under strain from two directions. The Iran war's fertiliser shock has been raising planting costs through the year, and the Black Sea grain trade has been crippled by drone strikes on ports at both ends. Adding a monsoon failure and a southern African drought to that is not an additive problem, it is a multiplicative one.

The countries with the least room are the ones that always have the least room. Nigeria was already facing its worst food security crisis in nearly a decade before this event formed, and Malawi's economic troubles have deepened poverty through a run of bad harvests.

There are offsets. India's rice surplus is heading for record exports and would cushion a lot of Asian and African import bills if it survives the monsoon. The Reserve Bank of India has been explicit that its own persistent food inflation is climate-driven, which is at least a central bank that has stopped treating weather as noise.

What it does to the temperature record

El Niño lends the planet heat it has been storing. Roughly, a 1C shift in Niño3.4 translates to about 0.1C on the global average, with a lag of three to six months.

That is why the big events show up as record years: 1998, 2016 and 2024 were all El Niño-boosted. It is also why those records keep falling. In the ERA5 dataset, 1998 was a record at the time, then 2005 beat it, then 2010, 2015, 2016, 2023 and 2024.

Strip ENSO out of the series and the peaks and troughs flatten, but the line still climbs. El Niño and La Niña are the largest source of year-to-year variability in global temperature; human-caused warming is what sets the direction. A record El Niño on top of the warmest baseline yet recorded is the reason 2027 is being watched.

The consequences of that baseline are already being priced. IntelliNews has reported that 3bn people will live in uninhabitable zones by 2070, and each disaster season arrives with heatwaves, floods and fires in more places at once.

Is warming making El Niño worse

This is genuinely unsettled, and worth stating plainly rather than resolving for effect.

The IPCC's 2021 assessment found that El Niño intensity, and the frequency of high-magnitude events, has increased since 1950 compared with periods stretching back to 1400. But proxy records from tree rings and sediment cores show El Niño frequency and intensity varying widely across the past 11,000 years, which makes attributing the recent shift to human warming difficult.

One 2017 study projected El Niño events could double in frequency at 1.5C of warming. In June 2026 the New York Times put the question to 16 climate scientists; eight said they see compelling evidence that warming is intensifying these events.

Half of a small sample is not a consensus. It is, however, enough for the people who set interest rates to start budgeting for it - which is the practical answer to the scientific question, arrived at from the other end.