The naturally-occurring El Niño event, which helped fuel a spike in global temperatures and extreme weather events around the world from 2023 to 2024, is showing signs of ending, according to an update from the World Meteorological Organisation (WMO).
There is likely to be a swing back to cooler La Niña conditions later this year in the Pacific Ocean, the WMO predicted on Monday, but impacts of climate change, including exceptionally high temperatures, are likely to continue in parts of the world driven by human-induced climate change.
La Niña refers to the large-scale cooling of the ocean surface temperatures in the central and eastern equatorial Pacific Ocean, coupled with changes in the tropical atmospheric circulation, namely winds, pressure and rainfall, which have a global impact. The effects of each La Niña event vary depending on the intensity, duration, time of year it develops, and the interaction with other modes of climate variability. In many locations, especially in the tropics, La Niña produces the opposite climate impacts to El Niño.
However, naturally occurring climate events now take place in the context of climate change, which is increasing global temperatures, exacerbating extreme weather and climate, and impacting seasonal rainfall and temperature patterns, the WMO added.
“Every month since June 2023 has set a new temperature record – and 2023 was 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 high sea surface temperatures will continue to play an important role during the next months,” said WMO deputy secretary general Ko Barrett.
The past nine years have been the warmest on record even with the cooling influence of a multiyear La Niña from 2020 to early 2023. El Niño peaked in December 2023 as one of the five strongest on record.
“Our weather will continue to be more extreme because of the extra heat and moisture in our atmosphere. This is why the Early Warnings for All initiative remains WMO’s top priority. Seasonal forecasts for El Niño and La Niña and the anticipated impacts on the climate patterns globally are an important tool to inform early warnings and early action,” said Ms Barrett, who is leading a WMO delegation at the UN climate change talks in Bonn this week.
“La Niña conditions generally follow strong El Niño events, and this is in line with recent model predictions, although high uncertainty remains regarding its strength or duration,” the WMO said.
Latest forecasts from WMO global producing centres of long-range forecasts give equal chances (50 per cent) of either neutral conditions or a transition to La Niña during June-August 2024. The chance of La Niña conditions increases to 60 per cent during July-September and 70 per cent during August-November. The chance of El Niño redeveloping is negligible during this time, it confirmed.
The latest global seasonal climate update, however, says widespread above-normal sea-surface temperatures in all areas are expected to persist outside the near-equatorial eastern Pacific Ocean. “There is therefore widespread prediction of above-normal temperatures over almost all land areas.”
Predictions for rainfall are, in part, consistent with the typical impacts of the early stage of La Niña conditions, including above-normal rainfall in far northern South America, Central America, the Caribbean, northern Greater Horn of Africa and the Sahel, parts of southwest Asia and central Maritime Continent.
The upcoming Atlantic hurricane season is expected to have above-normal activity due to a confluence of factors, including near-record warm ocean temperatures in the Atlantic Ocean, development of La Nina conditions in the Pacific, reduced Atlantic trade winds and less wind shear,” the National Oceanic and Atmospheric Administration said last month.
WMO Updates and are available to support governments, the UN, decision-makers and stakeholders in climate-sensitive sectors to mobilise preparations and protect lives and livelihoods.
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