All naturally occurring climate events, such as El Niño, currently occur in the context of human-caused climate change, which is causing global temperatures to rise. Pictured: Bangladesh WMO: El Niño will change to La Niña before the end of this year. What does this mean? Climate and Environment
The El Niño phenomenon observed throughout 2023 and 2024 contributed to a surge in global temperatures and extreme weather events around the world. A return to La Niña conditions is likely to occur later this year, according to a new World Meteorological Organization (WMO) El Niño/La Niña bulletin. Does this mean it will get cooler?
Forecasting models
The latest estimates from the WMO Global Long-Range Forecast Centers give an equal chance (50 percent) of either neutral conditions or a transition to La Niña in June–August 2024. The probability of La Niña occurring increases to 60 percent in July–September and to 70 percent in August–November. The probability of El Niño re-developing at this time is “negligibly small,” according to WMO experts.
The influence of other factors
La Niña is associated with widespread cooling of the ocean surface in the central and eastern equatorial Pacific, coupled with changes in tropical atmospheric circulation, namely wind, pressure and precipitation. The effects of each La Niña event vary depending on the intensity, duration, time of year in which it occurs, and interactions with other parameters.
Anthropogenic Climate Change
In many places, especially in the tropics, La Niña has the opposite effect on climate than El Niño. However, all naturally occurring climate events such as the El Niño/Southern Oscillation (ENSO) currently occur in the context of human-induced climate change, which is increasing global temperatures, increasing extreme weather and climate events, and affecting seasonal rainfall patterns and temperatures.
The warmest year
“Each month since June 2023 has set a new temperature record, and 2023 is by far the warmest year on record. The end of El Niño does not mean a pause in long-term climate change, as our planet will continue to warm due to heat-trapping greenhouse gases. “Exceptionally warm sea surface temperatures will continue to play an important role over the coming months,” said WMO Deputy Secretary-General Co Barrett.
The past nine years have been the warmest on record. , even despite the cooling influence of a multi-year La Niña between 2020 and early 2023. El Niño peaked in December 2023, one of the five strongest on record.
Extreme weather events will continue
“The weather will continue to be more extreme than previously due to additional heat and moisture in the atmosphere. This is why the Early Warnings for All initiative remains a top WMO priority. Seasonal forecasts of El Niño and La Niña and expected impacts on global climate models are an important tool to help assess the situation in advance and take action,” said Ko Barrett, who is leading the WMO delegation to the United Nations Climate Change Conference in Bonn.
“Barriers to Predictability”
La Niña events usually follow strong El Niño events, and this is consistent latest model forecasts, although there remains high uncertainty about their magnitude or duration. Seasonal forecasting models are known to have a relatively low success rate at this time of year, commonly referred to as the “Northern Hemisphere spring predictability barrier.”