The warnings about El Niño continue to roll in. The United Nations' weather agency weighed in on Oct. 21, calling the potent climate pattern a "behemoth" and a "wrecking ball."
"It will tear through Latin America, Eastern and Southern Africa, Asia and the Pacific with extreme heat, droughts and flood," the U.N.'s Tom Fletcher said, warning of profound humanitarian consequences.
El Niño, a natural warming of Pacific Ocean waters that affects weather and climate patterns worldwide, tends to cause higher global temperatures and disrupt rainfall patterns across large regions, meaning drought in some areas and heavy rains in others.
It triggers disruptive weather patterns that often impact agriculture, infrastructure and supply chains, potentially causing
trillions of dollars in damages around the globe.
This El Niño is already at record strength and is expected to continue to intensify over the next few months, NOAA's Climate Prediction Center has said.
"This will certainly be an historic El Nino," Michael Mann, a climate scientist and professor at the University of Pennsylvania, told USA TODAY. It will be the "biggest event on record," but because reliable records only go back less than a century, it's difficult to assess how unusual it is in a longer-term context, Mann said.
'Unprecedented in strength'
As ocean temperatures continue to warm in the eastern Pacific, the World Meteorological Organization (WMO) warned on Oct. 21 that the developing El Niño could be "unprecedented in strength."
“This is literally off the monitoring charts that we have used for the past four decades," said Celeste Saulo, secretary of the WMO. The event is forecast to peak later in 2026, "but its impacts will be felt long after that," Saulo said.
The WMO expects the El Niño event to become extremely strong, with temperatures in the central Pacific rising more than 6 degrees (3.8 Celsius) above normal between November and January, peaking around December.
Extreme weather events already being reported are expected to "multiply – and cascade – as El Niño intensifies," the WMO warned.
Forecasts for the event are "very high confidence now and the very strong El Niño will certainly last through the next several months," said Emily Becker, deputy director of the Cooperative Institute for Marine & Atmospheric Studies at the University of Miami's Rosenstiel School for Marine, Atmospheric & Earth Science.
El Niño is likely to strengthen further, but at this point, forecasters already have as much information as they'll ever have about the expected impacts, and the seasonal outlooks reflect that, Becker said. She added that it's "important to remember that the weather is always full of surprises, and even in a strong El Niño it’s critical to monitor short-term weather and sub seasonal forecasts."
El Niño adding to climate change effects
One of the important things to note about this El Niño event is that it's converging with the impacts of human-caused climate change, such as sea level rise, said Fraser Shilling, director of the UC Davis Road Ecology Center, at the Institute of Transportation Studies, in a recently published study for California.
El Niño warming "adds to human-caused warming in such a way that we see new records set every time we get a major El Nino event," said Mann. He was a lead author on a study released earlier this year that found El Niño "contributed substantially to the record 2024 global temperatures."
"The science is very unclear about whether we are seeing or expect to see an increase in the amplitude of El Nino events from human-caused warming," Mann said, with many models predicting the opposite will occur.
The extreme levels of warmth associated with major El Niño events are temporary, he said, but the events such as those discussed in the United Nations announcement give us a glimpse of "what our future will look like if we continue to warm the planet."
US impacts from El Niño
In the United States, a very strong El Niño tilts the odds toward stormier weather across the South, said Ken Graham, director of NOAA’s National Weather Service. Graham warned the nation earlier in October to prepare for its impacts. “While higher chances of rain and snow may bring relief to drought-afflicted areas, too much precipitation on dry soil can fuel destructive flash floods and mudslides," he said.
In California, Gov. Gavin Newsom recently declared a state of emergency to prepare for the impacts from the event.
Shoreline flooding already seen along the Southern California coast with this El Niño raises concerns for the coming months, according to the report Shilling released. California's Highway 37 and other coastal roadways are "extremely vulnerable to floods and failure during this winter’s coming El Niño," Shilling said. “It’s important to be informed of risk so you can make decisions.”
WMO report details global impacts
The WMO's outlook warned of the following potential impacts this winter:
- The Americas: Increased rainfall in the southern parts of western South America and in portions of North America and the northern portion of the Caribbean, while drought risk increases in parts of Central America, the southern Caribbean and the Amazon.
- East Africa: Wetter-than-normal conditions likely during the October–December rainy season, increasing concerns about heavy rainfall and flooding.
- Southern Africa: Increased risks of drier conditions could affect crop production, water availability and livelihoods from the typical start of the rainy season in November.
- Southeast Asia: Warmer conditions and rainfall deficits increase the risk of heat exposure and place additional pressure on agriculture and water supplies, like the increase in wildfire and smoke-haze risks we are already seeing.
Contributing: Reuters
Doyle Rice and Dinah Voyles Pulver are national correspondents for USA TODAY, focusing on climate and weather. Reach them at drice@usatoday.com and dpulver@usatoday.com.
This article originally appeared on USA TODAY: 'Behemoth' El Niño to upend global weather, UN warns
