The La Niña weather phenomenon, with its lower temperatures, could develop in the next three months, but it will be “short and of low intensity” and insufficient to offset the effects of global warming, the UN said on Wednesday. There is a 55% probability that a La Niña episode will develop “during the period from December 2024 to February 2025”, according to the latest bulletin published by the World Meteorological Organization (WMO).
In the previous bulletin, published in September, the probability of La Niña appearing during the period from December to February was estimated at 60%.
“The year 2024 began with El Niño and is on track to become the hottest year on record,” notes WMO Secretary General Celeste Saulo in a press release. “Even if the La Niña phenomenon, known to temporarily cool the climate, occurs, it will not be enough to counterbalance the warming induced by record levels of greenhouse gases, the specificity of which is to trap heat in the atmosphere », she comments.
Subsequently, for the period from February to April 2025, the return to neutral conditions is “the preferred scenario”, with a probability of also 55%.
In general, La Niña produces large-scale climate variations opposite those associated with El Niño. The phenomenon corresponds to large-scale cooling of surface waters in the central and eastern equatorial Pacific, associated with variations in tropical atmospheric circulation, for example winds, pressure and precipitation, explains WMO.
The WMO recalls that climatic phenomena of natural origin, such as La Niña and El Niño, are part of “a broader context of climate change” linked to human activities, “which causes global temperatures to rise, accentuates extreme weather and climate conditions and changes seasonal patterns of precipitation and temperatures.
Thus, underlines Ms. Saulo, “despite the absence of El Niño or La Niña conditions since May, we have witnessed an extraordinary series of extreme weather phenomena, including record rainfall and flooding which have unfortunately become the new normal in the context of climate change.
