A super El Ni帽o led to flooding in China in 1998 ROBYN BECK/AFP via Getty Images
In the past month, weather models have begun to show that a very strong El Ni帽o climate phase could develop later this year, potentially the strongest we have ever seen.
Many are calling this a 鈥渟uper El Ni帽o鈥 or even a 鈥淕odzilla El Ni帽o鈥. It could bring droughts to some areas of the world, floods to others and set the planet up for the hottest year on record.
鈥淭he forecast from now is warming faster in the tropical Pacific than at any other time so far this century,鈥 says at the Met Office, the UK’s national weather service. 鈥淪o something unusual is going on.鈥
What is a Super El Ni帽o?
El Ni帽o is a natural climate pattern that raises temperatures and disrupts weather around the world. It typically happens when the trade winds blowing east to west over the tropical Pacific weaken, reducing the upwelling of deep cold water and allowing warm surface water to slosh back across the central and eastern Pacific. Atmospheric circulation shifts eastward in turn.
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The El Ni帽o begins when sea surface temperatures in the central Pacific reach 0.5掳C above the long-term average. If they reach 2掳C or more above the long-term average, it鈥檚 a very strong or 鈥渟uper鈥 El Ni帽o.
Peruvian fishers noticed the warming tends to peak in December, which is why they called it El Ni帽o after the Christ child.
While El Ni帽o happens every few years, super events have only occurred in 1982-83, 1997-98 and 2015-16.
How likely is it to happen?
A burst of westerly winds in March and early April has been blowing massive amounts of warm water towards the central and eastern Pacific, setting the stage for a strong or very strong El Ni帽o. Met Office models the temperature anomaly there will near 2掳C by September, and a group of models run by the European Centre for Medium-Range Weather Forecasts (ECMWF) gives a roughly 50 per cent chance of reaching a 2.5掳C anomaly by October.
The US National Weather Service has projected a 25 per cent chance of a super El Ni帽o by the end of the year. If two of the models in the European group that are central Pacific temperature anomalies above 3掳C by September turn out to be correct, then this will be the El Ni帽o ever observed.
But the signs of a developing El Ni帽o are still faint at this point, and models struggle to make accurate predictions, a phenomenon known as the “spring predictability barrier”. Meteorologists will have a better idea of the strength of the coming El Ni帽o in May or June.
What are the impacts on weather?
The changes in atmospheric circulation over the central and eastern Pacific spread through long-distance 鈥溾, altering weather patterns around the world. That can lead to impacts like crop failures, coral bleaching and disease spread and cause billions of pounds in damages.
鈥淭hings are perturbed, they’re shifted away from normal,鈥 says at the ECMWF. 鈥淚t’s not necessarily that the storms, let’s say rainfall, is more鈥 It’s just happening in places that don’t normally get it.鈥
El Ni帽o typically brings more stormy, wet weather to the southern coasts of North and South America, the Horn of Africa and China, raising the risk of flooding.
At the same time, hot, dry weather tends to hit places like Australia and South-East 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 north-western Europe. There, El Ni帽o can raise the chances of hotter summers and colder winters, but it can also bring wet, mild winters, depending on what other climate patterns do.
Disastrous effects can continue after El Ni帽o has peaked. In the summer following the 1997-98 super El Ni帽o, severe rainfall and in China鈥檚 densely populated Yangtze river valley 3000 people, destroyed the homes of 15 million and caused $20 billion in economic losses.
The one piece of good news is that fewer hurricanes form off the Caribbean and east coast of the US during El Ni帽o. Amplified atmospheric circulation results in greater wind shear, so these storms tend to blow themselves out quickly, rather than gradually developing into huge hurricanes.
How will it affect the climate?
If climate change is like an incoming tide, gradually raising temperatures, then El Ni帽o is like a giant wave that temporarily boosts them even more. A strong event could increase global temperatures by 0.2掳C.
The last time El Ni帽o occurred, in 2024, it brought the hottest year on record, with global temperatures briefly exceeding the Paris Agreement limit of 1.5掳C for the first time. If a super El Ni帽o develops, many think 2027 will set a new record.
鈥淕iven that we鈥檙e already… close to 1.4, it鈥檚 quite likely or plausible that 2027 is going to go above the 1.5 threshold,鈥 says Scaife. 鈥淚t鈥檚 a sign that [global warming is] getting very close to the Paris threshold.鈥
Are we going to see more super El Ni帽o events?
El Ni帽o temperatures in the central Pacific are getting hotter due to climate change, but so is the long-term average of temperatures that they are compared to, so we shouldn’t see an increase in the number or strength of El Ni帽o temperature anomalies under this definition. For this reason, the US National Weather Service has begun classifying El Ni帽o by how much warmer the central Pacific is than other parts of the tropics at present, although this new definition has yet to be picked up elsewhere.
Instances of El Ni帽o and its cooler counterpart La Ni帽a have been more frequent and more extreme over the past 50 to 60 years. One suggested climate change has amplified these swings between warm and cooler temperatures in the central Pacific by 10 per cent. But given that we only have about 150 years of data, and our early measurements were , most scientists are still reluctant to say climate change is supercharging El Ni帽o.
鈥淚t鈥檚 a very tricky question, will El Ni帽o change under climate change,鈥 says Stockdale. 鈥淭he answer is it probably will.鈥
What is clear is that global warming is worsening the impacts of El Ni帽o. Elevated global temperatures lead to more evaporation from the soil and more moisture held in the atmosphere, which amplifies extreme weather like droughts and flooding.
鈥淲e call it an intensification of the hydrological cycle,鈥 says Stockdale. 鈥淏ecause El Ni帽o can cause significant changes in normal precipitation it can be exacerbated by climate change.鈥
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