A weather cycle known as El Nino has officially formed in the Pacific Ocean – which will likely add more heat to a warming planet.
The pattern could contribute to extreme events including droughts and cyclones across the world.
It formed a month or two earlier than most El Ninos do, which “gives it room to grow”, said the US National Oceanic and Atmospheric Administration (NOAA).
A strong El Nino has led to record global warmth in the past, like in 2016. And coupled with warming from climate change, 2023 or 2024 could be even hotter.
An El Nino is declared when ocean temperatures in the tropical eastern Pacific Ocean, near the coast of South America, rise 0.5C above the long-term average.
That part of the Pacific shifts weather patterns across the globe, often by moving the airborne paths for storms.
The effects of El Nino often peak during December.
There is a 56% chance that when this El Nino peaks in strength it will be considered a strong event, meaning eastern Pacific sea surface temperatures are at least 1.5C higher than normal.
And there is a 25% chance it reaches supersized levels, said climate scientist Michelle L’Heureux, head of the NOAA’s El Nino/La Nina forecast office.
Its name in Spanish means “the boy” and it is thought to have originated as “El Nino de Navidad” centuries ago when Peruvian fishermen named the weather phenomenon after the newborn Christ, according to the Met Office.
After three years of the cooler La Nina (the girl) pattern, which often lowers global temperatures slightly, the hotter El Nino is back.
For the next few months, during the northern hemisphere summer, El Nino will mostly be felt in the southern hemisphere with “minimal impacts” in North America, Ms L’Heureux said.
More intense weather events may include tropical cyclones moving towards vulnerable Pacific islands, heavy rainfall in South America and droughts in Australia.
Winter crop production in Australia could fall by 34% from record highs.
El Nino could also hit palm oil and rice production in Indonesia and Malaysia – which supply 80% of the world’s palm oil – and Thailand.
“The onset of El Nino has implications for placing 2023 in the running for warmest year on record when combined with climate-warming background,” University of Georgia meteorology professor Marshall Shepherd told NBC News.