This year’s El Niño is on track to be the strongest on record. It could also be a glimpse of our climate future.
This year’s El Niño is shaping up to be the strongest ever recorded, increasing the odds of never-before-seen weather extremes around the world.
A natural warming cycle of the tropical Pacific, the phenomenon was noted by Peruvian fishermen and sailors as far back as the 1600s. They named it “El Niño” — Spanish for “the Christ child” — because it peaked around the Christmas holiday. This year’s El Niño started in June, should peak around December and will fade in mid-2027.
This record El Niño is expected to steer winter storms farther south, raising the odds of a wetter season across much of the southern U.S. — from California to Florida and up the East Coast — bringing higher chances of heavy rain, flooding and record snow. The Pacific Northwest, by contrast, leans warmer and drier, making devastating wildfires more likely. El Niño also raises sea levels on both U.S. coasts, so high tides bring a greater risk of coastal flooding.
Every El Niño is different, but because this one is on a trajectory to break ocean heat records, it is almost certain to bring changing weather patterns.
This year’s El Niño is also unfolding amidst the hottest global temperatures on record, offering a glimpse of how extreme weather may be amplified as the planet warms, says climate scientist Fiona Lo, who studies how climate change affects weather systems at the global nonprofit Environmental Defense Fund.
As climate change pushes global temperatures higher over the coming decades, some of the extreme weather associated with El Niño’s cyclical warming — normally every two to seven years — could become more common or more intense.
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Why does El Niño so dramatically affect the world’s weather?
Right now, the surface of the tropical Pacific is more than two degrees Celsius above normal. Although El Niño is defined by warmer than normal temperatures in one small part of the globe, it produces ripple effects in weather patterns worldwide.
El Niño’s widespread impact on weather systems in the U.S. is largely driven by changes in the jet stream, Lo explains.
"When the tropical Pacific Ocean warms, it shifts where the ocean releases heat into the atmosphere — and that can change the jet stream, which is the main highway that helps steer weather systems,” says Lo. “When that highway shifts, weather systems can also shift.”
For instance, El Niño can affect how much it rains, and where. The effects on the weather can raise the chances of drier conditions in normally wet places, like Seattle, and wetter conditions in normally arid regions, like southern California. Shifts in the jet stream can also bring milder weather to locations that are normally pummeled by storms and increase odds of supercharged storms in other locales.
Because this El Niño is expected to be so strong, the odds of seeing these impacts are greater. But there are many variables at play. “The weather is governed by more than just El Niño, and every El Niño is different,” Lo points out.
One prediction scientists agree on? This is shaping up to be the strongest El Niño they’ve ever seen.
Climate scientists will be watching closely to see how this year’s El Niño evolves and shapes global weather patterns.
Is climate change making El Niño stronger?
It’s unclear if climate change is strengthening El Niño itself.
Since the mid-20th century, Lo says, El Niños have become more extreme. "There may be a trend, but we can’t say for sure that there’s a direct correlation with human-caused climate change.
“There’s just not enough data for us to say, ‘yes, this correlation is certain,’” Lo continues. “Us climate scientists are a very conservative bunch of folks — we have to be pretty certain to say that!”
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This climate scientist remains hopeful
Lo has researched climate change and sounded the alarm about its impacts for decades. While these kinds of predictions might sound frightening or depressing, Lo remains hopeful.
“What gives me hope is that we’re extremely innovative as human beings,” Lo says. “A lot of work here at EDF is looking at new and innovative energy technologies that can help us reduce greenhouse gas emissions, including cutting methane emissions — the fastest way to reduce warming in the near term.”
Lo has noticed that public attitudes are changing, too.
“We are seeing so much more awareness and urgency,” Lo continues. “Years ago, when people found out what I studied, it wasn’t uncommon for someone to say, ‘climate change isn’t real!’ But now when I tell people what I do, they usually say ‘thank you for your work.’ It’s very encouraging.”
Lo adds that as extreme weather intensifies, more people are looking for ways to avoid fossil fuels and adopt clean, renewable energy. “A lot of these things are starting to add up,” she says. “I think we are starting to see a groundswell.”
The evolution of climate science during Lo’s own career also inspires hope.
"Over my three decades in climate science, the field has made enormous progress," Lo says. "We understand much more about how the climate is changing and where greenhouse gas emissions come from — so we can act more strategically to cut pollution and lower climate change risks.
“For me, that's the most important role of climate science,” she adds. “It doesn't just help us understand the problem — it shows us what we can do about it."
