Is a super El Niño imminent, and what could the impacts be?

Over the past month, weather models have started to show that a very strong El Niño weather phase could develop later this year, potentially the strongest we have ever seen.

Many are calling this a “super El Niño” or even a “Godzilla El Niño.” This could cause droughts in some parts of the world, floods in others and prepare the planet for the hottest year on record.

“We are now forecasting faster warming in the tropical Pacific than at any other time this century,” says Adam Scaife of the Met Office, the UK’s national weather service. “So there’s something unusual going on.”

What is a Super El Niño?

El Niño is a natural climate phenomenon that raises temperatures and disrupts weather patterns around the world. This typically occurs when the trade winds blowing from east to west over the tropical Pacific weaken, reducing the upwelling of deep cold water and allowing warm surface waters to flow back across the central and eastern Pacific. The atmospheric circulation in turn moves eastward.

El Niño begins when sea surface temperatures in the central Pacific reach 0.5°C above the long-term average. If they reach 2°C or more above the long-term average, it is a very strong or “super” El Niño.

Peruvian fishermen noticed that warming tended to peak in December, so they called it El Niño, after the Baby Jesus.

Although El Niño occurs regularly, super events only occurred in 1982-83, 1997-98 and 2015-16.

How likely is this to happen?

A burst of westerly winds in March and early April blew huge amounts of warm water toward the central and eastern Pacific, setting the stage for a strong or very strong El Niño. Met Office models predict the temperature anomaly will be around 2°C by September, and a group of models run by the European Center for Medium-Range Weather Forecasts (ECMWF) give around a 50% chance of reaching a 2.5°C anomaly by October.

The U.S. National Weather Service predicts a 25 percent chance of a super El Niño occurring by the end of the year. If two of the European group’s models that project temperature anomalies in the central Pacific greater than 3°C by September prove correct, then it will be the strongest El Niño ever observed.

But signs of a developing El Niño are still weak at this point, and models are struggling to make accurate forecasts, a phenomenon known as the “spring predictability barrier.” Meteorologists will have a better idea of ​​the strength of the next El Niño in May or June.

What are the impacts on the weather?

Changes in atmospheric circulation in the central and eastern Pacific have spread through long-distance “teleconnections,” altering weather patterns around the world. This can lead to consequences such as crop failure, coral bleaching and the spread of disease, and cause billions of pounds of damage.

“Things are disrupted, they are moving away from normal,” says Tim Stockdale of ECMWF. “It’s not necessarily that the storms, let’s say precipitation, are more… It’s just happening in places that don’t normally get hit.”

El Niño typically brings more stormy and rainy weather to the southern coasts of North and South America, the Horn of Africa and China, increasing the risk of flooding.

At the same time, hot and dry weather tends to affect regions like Australia and Southeast Asia, central and southern Africa, India and the Amazon rainforest, increasing the risk of drought, heatwaves and wildfires.

The effects are more complex in the UK and northwest Europe. There, El Niño can increase the chances of warmer summers and colder winters, but it can also cause wet and mild winters, depending on how other weather patterns play out.

The disastrous effects can persist after the peak of El Niño. In the summer following the 1997-98 super El Niño, heavy rains and flooding in China’s densely populated Yangtze River valley killed 3,000 people, destroyed the homes of 15 million, and caused $20 billion in economic losses.

The only good news is that fewer hurricanes form off the Caribbean and U.S. East Coast during El Niño. The amplified atmospheric circulation leads to greater wind shear, so these storms tend to die out quickly, rather than gradually transforming into huge hurricanes.

What impact will this have on the climate?

If climate change is like a rising tide, gradually raising temperatures, then El Niño is like a giant wave that temporarily causes them to rise even higher. A violent event could increase global temperatures by 0.2°C.

The last time El Niño occurred, in 2024, it was the hottest year on record, with global temperatures briefly exceeding the 1.5°C limit set by the Paris Agreement for the first time. If a super El Niño develops, many believe 2027 will set a new record.

“Given that we are already… close to 1.4, it is entirely likely or plausible that 2027 will exceed the threshold of 1.5,” says Scaife. “It’s a sign that [global warming is] we are getting very close to the threshold of Paris.

Are we going to see more super El Niño events?

El Niño-related temperatures in the central Pacific are becoming warmer due to climate change, as are the long-term average temperatures they are compared to. We should therefore not see an increase in the number or intensity of El Niño-related temperature anomalies under this definition. For this reason, the United States National Weather Service has begun classifying El Niño by the current temperature of the central Pacific relative to other tropical regions, although this new definition has not yet been adopted elsewhere.

El Niño events and its colder counterpart, La Niña, have been more frequent and more extreme over the past 50 to 60 years. One study suggests that climate change has amplified these variations between warm and cooler temperatures by 10% in the central Pacific. But because we only have about 150 years of data and our early measurements were less reliable, most scientists are still hesitant to say that climate change is amplifying El Niño.

“It’s a very tricky question: Will El Niño change as a result of climate change,” Stockdale says. “The answer is that it probably will.”

What is clear is that global warming is making the effects of El Niño worse. High global temperatures lead to more evaporation from the ground and more moisture into the atmosphere, which amplifies extreme weather events like droughts and floods.

“We call this an intensification of the hydrological cycle,” says Stockdale. “Because El Niño can cause significant changes in normal precipitation, it can be exacerbated by climate change. »