What is El Niño?

What is El Niño?

You might’ve seen headlines about a super El Niño developing over the past few months. Scientists say it’s going to be a record-breaker in terms of high ocean temperatures in the Pacific, and it’s set to impact the climate, food supply and the global economy. So in this Squiz Shortcut, we’ll take a look at:

• What El Niño is

• What it could bring

• And what we can expect here in Australia

🙋🏻‍♀️ This newsletter was written by Larissa Huntington

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Squiz the Shortcut

Let’s start with the basics… What is El Niño?
It’s a natural climate phenomenon where we see the ocean surface in the central and eastern Pacific Ocean warm up. It comes around every 2 to 7 years and typically lasts for about a year.

What happens?
The winds that would normally push those warmer waters westwards aren’t as strong, or they change direction, meaning the water in the eastern parts of the ocean gets warmer than usual (kind of like a big swimming pool). Heat is then released into the atmosphere through evaporation and that can increase global temperatures and change weather patterns.

Why is this one making headlines?
Because forecasters are warning that it’s likely to be bigger and stronger in 2026-27 than any El Niño event recorded in at least 150 years. It’s being called a Super Godzilla Monster El Niño - which sounds quite alarming. What it means in real terms is that we could see a summer where extreme weather events in some parts of the world are supercharged. El Niño is one of 3 climate states that scientists watch pretty closely...

What are the others?
You might’ve heard of La Niña, which happens when ocean surface temperatures in the Pacific are below average. And then there’s a neutral state, where the temps are about average. When these events happen, they generally develop between April and June, and then they reach full strength later in the year between October and February. 

What’s expected this time?
The warming sea temperature of El Niño can range between 1C and 3C which has a huge effect on different regions. Reports for this event say temps have already broken the 3.02C record set in 2015 to reach 3.11C above average. Now, every El Niño is different, so the impacts on weather patterns aren’t guaranteed. But usually it increases the chance of storms and floods in some regions and drought and bushfires in others…

What are some of the impacts?
It can have knock-on effects for crop yields (and in turn food supplies), the health of people and animals, and economies around the world. In the early stages of this event we’ve seen record bushfires in Indonesia affecting air quality for millions of people, less rainfall in India than usual which impacts food supplies, and drought in Central America which does the same. There’s been flooding in South America, and a giant hurricane (Nolo) in the middle of the Pacific Ocean… And scientists say this is well before it’s peaked. 

What’s predicted?
It’s expected to peak at 4C in November or December according to 14 climate models. That’s so far above the previous events that leading climate scientists have called it “mind-blowing” - which is where the labels of Godzilla and super El Niño have come from. And they’re also saying that climate change is adding to the issue. 

How is climate change playing a part?
Climate researchers say human use of fossil fuels is contributing to global warming and amplifying the effect of El Niño. And UN secretary general António Guterres has weighed in, saying: “El Niño is being supersized before our eyes. The science leaves no room for doubt: the planet is in uncharted waters, and those waters are heating up.” The additional heat that El Niño is predicted to transfer into the atmosphere has forecasters saying 2027 will be the hottest year on record. 

What does it mean for people?
Studies are showing that more than 450,000 people could die of heat-related causes before it’s over. The countries with the highest projected tolls are Nigeria, Sudan, Indonesia, India and Brazil. But Australia isn’t exempt. 

What do the numbers say about Oz?
We’re also predicted to experience 260 more heat deaths than the 30-year average, according to a study run by the University of Chicago's Climate Impact Lab, and most of those are expected to be in Western Oz and NSW. 

And what are we in for in terms of weather?
El Niño usually brings lower than average rainfall, particularly in the east of the country, along with higher daytime temps in southern areas. The Bureau of Meteorology says that this El Niño is likely to be very strong, but it’s pointed out that it doesn't always mean we’ll see a big impact here in Oz. Basically, it’s too soon to tell how summer will play out.

How hot have things been getting in Oz?
This century, we’ve experienced 14 of our 15 warmest years on record, and the additional heat in the tropical Pacific that emerges during El Niño events typically boosts global temperatures, meaning we are in for another hot one. But it doesn’t necessarily mean a drought for us this time. There are other factors to take into account. 

What other factors do we look at?
Another climate pattern we pay attention to in Oz is the Indian Ocean Dipole… It’s caused by a regular shift in ocean temperatures between the western and eastern sides of the Indian Ocean. It acts like a giant see-saw of warm water and it heavily influences weather, rainfall, and temperatures across Africa, Asia, and Australia. It can sometimes offset El Niño’s effects. But this year, a positive IOD would mean a double whammy for Australia as far as high temperatures go. 

Just explain that a bit more…
At the moment, it’s neutral, but the Bureau says a positive IOD could develop in spring. That would effectively mean warm water shifting away from Indonesia and northern Australia toward East Africa, which would prevent evaporation and cloud formation, cutting off the moisture that usually travels into southern and southeastern parts of the country.

Doesn’t that mean we could be in for a drought?
That’s what we'd expect to happen normally… But this year, the temperature in the ocean around us in the west, south and south-east is unseasonably warm - up to 3C warmer than usual. The warm waters fuel storms and north-west cloud bands - massive corridors of cloud - which draw tropical air directly from the warm Indian Ocean and dump it straight across inland and western Australia. 

So we’re not in for a scorching summer like Europe’s just had?
The Bureau says there’s no direct link between northern hemisphere summers and ours. It says the outlook for summer will become clearer as we move through spring. But we know that dry Aussie summers typically lead to an increased risk of bushfires - and that’s something the Climate Council has warned about. 

What does the Climate Council say?
While a strong El Niño doesn’t automatically spell a drought, it tilts the scales toward below-average rainfall, hotter days, and increased bushfire risk across the eastern and southern states. And those conditions mean fire seasons are expanding at both ends - they’re beginning earlier, finishing later, and fires will burn more intensely when they do start. 

What else should I know?
The Climate Council also points out that the years following an El Niño have historically been when major fires have happened. When the Black Summer fires started in 2019, it wasn’t an El Niño year, but they followed the 2015-2016 El Niño that helped dry out south-eastern Oz. So there are already concerns about what the 2027-28 bushfire season might be like if there is no return to La Niña.

What’s the main take away?
The Bureau is keeping an eye on things, so watch the long-range forecast rather than assuming a strong El Niño automatically means a severe bushfire season in Oz. As the BOM has outlined, there are other factors to take into account like warmer oceans around the coast which could bring more rain than usual to inland areas and the west.

But temps through the day are still likely to be high?
They are… And with rainfall predicted to be below average in the south-east, authorities are calling for people in fire-prone areas to err on the safe side and start preparing sooner rather than later. 

Onto our Recommendations

Reading: This article from The Conversation about what we’re already seeing around the world from this El Niño - things like changing fish migration patterns and less port activity in the Panama Canal due to its low level caused by less rainfall…

Reading: This piece from The Guardian on how climate change is playing into things and what it could mean for Australia.

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