El Nino could return this year and make the Earth very hot. What you need to know.
A climate known as El Nino could form later this year, potentially pushing global temperatures to record highs.
There is a 50 to 60 percent chance of El Nino developing during the July-September period and beyond, according to the US National Oceanic and Atmospheric Administration (NOAA).
The World Meteorological Organization will issue an update on El Nino on Tuesday.
Here’s what you need to know about El Nino and its cooler sister, La Nina:
How was El Nino named?
El Nino and La Nina are two phases of a natural weather pattern across the tropical Pacific known as the El Nino-Southern Oscillation (ENSO).
Peruvian and Ecuadorian fishermen coined the name El Nino (“the boy” or “Christ Child”) in the 19th century for an unusually warm coastal current that reduced their catch before Christmas.
Scientists prefer the name La Nina as the opposite of El Nino. Between the two events, there is a “neutral” phase.
How does El Nino produce its warming effect?
El Nino can weaken the steady trade winds that blow east to west across the tropical Pacific, affecting the climate by affecting the movement of warm ocean waters.
This weakening warms the cooler parts of the central and eastern ocean, changing precipitation over the equatorial Pacific and global wind patterns.
More heat on the surface of the Pacific releases energy into the atmosphere that can temporarily raise global temperatures, which is why El Nino years tend to be among the warmest on record.
El Nino occurs every two to seven years.
It generally leads to dry conditions throughout Southeast Asia, Australia, southern Africa, and northern Brazil, and wet conditions in the Horn of Africa, southern United States, Peru, and Ecuador.
New records coming?
The last El Nino occurred in 2023-2024 and contributed to making 2023 the second-highest year on record and 2024 the highest.
Carlo Buontempo, director of the European Union’s Copernicus Climate Change Service, told AFP in January that 2026 could be “another record year” if El Nino appears this year.
However, the impact of El Nino could be higher in 2027 than in 2026 if it develops in the second half of this year, said Tido Semmler, a climate scientist at Ireland’s National Meteorological Service.
“It takes time for the Earth’s atmosphere to respond to El Nino,” he said.
“Having said this, there is a risk that 2026 will be the warmest year on record even if there is no El Nino, due to the hot weather. global warming it’s a habit,” Semmler told AFP.
“2027 will face an increased risk of experiencing a warm year if El Nino develops in the second half of 2026,” he added.
What about La Nina?
The latest episode of La Nina was weak and short-lived, starting in December 2024 and due to entering the neutral phase during the Februady-April period.
La Nina cools the eastern Pacific Ocean for about one to three years, producing the opposite effects of El Nino on global climate.
It leads to wet conditions in parts of Australia, southeast Asia, India, southeast Africa and northern Brazil, while it causes dry conditions in parts of South America.
La Nina didn’t stop 2025 from being the third hottest on record.
NOAA’s new determination formula
NOAA has adopted a new method for determining El Nino and La Nina events.
The old Oceanic Nino Index (ONI) compared the three-month sea temperature in one area of the Pacific to the 30-year average for the same area.
But with oceans warming rapidly, that 30-year-old estimate may be out of date.
The new method, the Relative Oceanic Nino Index (RONI), compares how warm or cool the east-central Pacific is compared to the rest of the tropics.
NOAA says RONI is a “clear, reliable way” to track El Nino and La Nina in real time.
