What previous Super El Niños can tell us about the next one

A resident observes the condition of a receding fishpond due to the El Nino phenomenon in Tangerang Regency, Indonesia, on October 17, 2023. (Kevin Herbian/NurPhoto/Getty Images via CNN Newsource)

The coming “Super” El Niño is poised to affect the lives of hundreds of millions of people worldwide as it strengthens through the year into the winter season. It may also alter ecosystems for decades to come, judging from the repercussions of past intense El Niños.

The last Super El Niño reshaped weather and economies around the world, leaving disruptions that lingered long after the Pacific cooled. Now, as another powerful El Niño builds, we’re looking for clues about what hundreds of millions of people — and the planet’s most fragile ecosystems — may face next.

El Niño is a naturally occurring weather cycle in the Pacific Ocean characterized by unusually hot waters near the equator, which changes the circulation of air in the atmosphere. But the effects of El Niño do not stay limited to that part of the Pacific; they ricochet outward to affect weather and climate patterns around the globe.

Past Super El Niños are an imperfect guide to this upcoming one, since no two El Niños are alike in their impact. But in many ways, we will be simultaneously more and less resilient to effects of this super El Niño compared to events in 1982-83, 1997-98 and 2015-16.

Most notably, some computer models show the upcoming El Niño exceeding the intensity of all those events to become the most intense since at least 1950. It’s not the most likely scenario, but that’s the biggest point of uncertainty in its impacts: We aren’t going to know its peak strength until it happens.

Our modern resilience comes from being able to see El Niño coming well before its worst effects hit. But there are some concerns that countries and aid groups may have a harder time mounting a response to El Niño-linked extreme weather events because of cuts to aid budgets and other political developments. These have especially affected some of the most vulnerable countries in the world.

The effects of a strong El Niño can include flooding in some areas while drought, heat waves and wildfires plague other regions. Crop losses are common in some countries during an El Niño, as is coral bleaching and mortality due to unusually hot ocean temperatures.

Because El Niño features a large area of unusually hot ocean waters, with much of that heat transferred to the atmosphere, the global climate is almost certain to see a record warm year during an intense El Niño, climate scientists say.

It will be costly

Studies of historical El Niño events, particularly the “El Niño of the Century” in 1997-98, have shown that their economic damage can run into the trillions globally, though some countries can benefit economically from the milder winters it brings or other weather pattern shifts.

A study published in the journal Science in 2023 found that El Niño can cut country-level economic growth for several years after the warm waters have subsided.

Researchers attributed $4.1 trillion in global income losses to the 1982-83 El Niño and $5.7 trillion in global income losses to the 1997-98 event, which, based on its intensity, may be a useful analog for the upcoming El Niño. These losses played out in countries across a five-year period during and following the El Niño.

El Niño isn’t the only game in town

During El Niño, and especially a Super El Niño, it can be tempting to blame each extreme weather event on the phenomenon. However, El Niño does not instigate individual weather systems so much as dial up or down the odds for particular conditions to prevail at a certain time of the year.

To put it plainly, there is no foreboding El Niño cloud that will appear above your house, and many random weather events will still occur that have few, if any, tangible links to the weather phenomenon.

In the U.S., for example, El Niño’s influence tends to peak during the winter months, with weaker correlations with weather patterns at other times of the year. And during the winter, El Niño’s role is to put its thumb on the scale and raise the odds of repeated atmospheric river events affecting California and wetter-than-average conditions across the southern tier of the U.S.

Milder than average winters tend to prevail across the northern half of the country.

Better forecasts have made it easier to prepare

The advent of accurate El Niño forecasts since the early 1980s is helping society become more prepared for the impacts of each El Niño. Knowing that one is coming can enable forecasters to make accurate projections for seasonal temperature and precipitation, as well as hurricane and typhoon seasons worldwide.

For example, it is known that El Niño tends to lead to fewer hurricanes in the Atlantic Ocean and above-average hurricane activity in the eastern and Central Pacific Ocean. In addition, it can boost the intensity of West Pacific typhoons.

As El Niño forecasts have grown more accurate over time, humanitarian groups, governments, companies and farmers have become more adept at preparing for its effects, though the most vulnerable and underserved communities may not have access to all of the information they need, said Andrew Kruczkiewicz, a researcher at Columbia University’s Climate School.

Already, he said, groups like the Red Cross and the Red Crescent Society are anticipating the need to stage food aid in regions that are more vulnerable to El Niño-related droughts, with supplies also going to locations like southeastern Africa, which can be susceptible to significant flooding in an El Niño year.

Prepare for surprises

In some respects, climate change makes this El Niño a wild card, since it will occur in a far warmer world than that of 2015-16 and 1997-98 — and especially 1982-83. A study published in January found that the typical impacts of El Niño in 2023-24 were “offset” by the abundance of warm water elsewhere in the global oceans.

Currently, nearly the entire tropical and Northern Pacific Ocean is warmer than normal. That could alter some of El Niño’s effects by influencing weather patterns.

“Climate change has made El Niño events of the past less informative for events today,” said Nathan Lenssen, a scientist at the NSF National Center for Atmospheric Research and Colorado School of Mines.

Kruczkiewicz has worked to get actionable intelligence on El Niño into the hands of people who can benefit most, including government officials and farmers in the developing world. Many times, he said, people have the memory of the previous El Niño in their minds and think the upcoming event is going to be the same, when that is far from a sure bet.

“The impacts can evolve in different ways and will evolve in different ways,” Kruczkewitz said.

The drastic cutbacks in U.S. foreign aid and dismantling of USAID under the Trump administration may make it more difficult to access and distribute food supplies and medicine in the wake of flooding, droughts or other El Niño-related weather disasters, Lenssen warned.

“El Niño events have historically caused drought and famine throughout the global south, and USAID has historically been key in supporting these populations before, during and after climate-driven famines,” Lenssen said.