El Niño is starting to die down - but it won’t spell the end of extreme weather, WMO warns
El Niño is starting to dial down - but it’s not over yet, the World Meteorological Organization (WMO) says.
The weather phenomenon that has worsened heatwaves, droughts and heavy rain since last June peaked as one of the five strongest on record in December.
There is a 60 per cent chance it will continue to fuel high temperatures and extreme weather events until May, according to WMO.
“Every month since June 2023 has set a new monthly temperature record - and 2023 was by far the warmest year on record,” says WMO Secretary-General Celeste Saulo.
“El Niño has contributed to these record temperatures, but heat-trapping greenhouse gases are unequivocally the main culprit.”
Sea temperature rise cannot be explained by El Niño alone
Global ocean temperatures are at a record high. This can partly be explained by El Niño, a naturally occurring seasonal climate phenomenon associated with the surface warming of the central and eastern tropical Pacific Ocean.
There, average surface temperatures peaked at 2°C above the 1991-2020 average between November and January. This made it one of the top five strongest El Niño events on record.
Though it was weaker than in 1997/98 and 2015/2016, when it last occurred, the current El Niño emerged quickly leading to weather extremes not seen in recent decades. It also followed an unusually long La Niña - El Niño’s cooling counterpart - which lasted three years.
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But it’s not the only cause of rising temperatures.
“Ocean surface temperatures in the equatorial Pacific clearly reflect El Niño. But sea surface temperatures in other parts of the globe have been persistently and unusually high for the past 10 months,” says Saulo.
“The January 2024 sea-surface temperature was by far the highest on record for January. This is worrying and can not be explained by El Niño alone.”
The weather pattern fuels warming from human-caused greenhouse gas emissions that trap heat in the atmosphere. The passing of El Niño will therefore not spell an end to weather extremes, which must be addressed by cutting emissions.
How does El Niño impact the weather?
El Niño occurs on average every two to seven years, and typically lasts nine to 12 months. It influences weather and storm patterns in different parts of the world, including making extreme weather events more likely in some regions.
In the Horn of Africa and the southern US, El Niño is associated with increased rainfall and flooding. In Southeast Asia, Australia and southern Africa, it brings unusually dry and warm conditions. While in northern South America it has worsened drought.
El Niño is expected to lead to above-normal temperatures across the globe and influence regional rainfall patterns over the next three months.
There is a chance of La Niña developing later in the year, but the odds are uncertain, WMO says. The two patterns typically oscillate every three to five years, with neutral conditions in between.