GENEVA

The World Meteorological Organization (WMO) on Wednesday issued a new update forecasting a 60% likelihood of La Nina's cooling impact emerging towards the end of 2024.

La Nina, characterized by the cooling of ocean surface temperatures in the central and eastern equatorial Pacific Ocean, is expected to develop following the current neutral El Nino-Southern Oscillation (ENSO) conditions, the WMO said in a statement.

It added that the probability of La Nina forming is forecast at 55% from September to November 2024 and is anticipated to rise to 60% from October 2024 through February 2025. Meanwhile, the chance of El Nino redeveloping during this period is considered negligible.

The phenomenon of La Nina often brings about cooling impacts on global climate, contrasting with the warming effects typically associated with El Nino, the update explained. While La Nina events can influence weather patterns such as rainfall and temperatures, their impacts vary based on factors such as intensity, duration, and interactions with other climate drivers.

"Since June 2023 we have seen an extended streak of exceptional global land and sea surface temperature," said WMO Secretary-General Celeste Saulo. "Even if a short-term cooling La Niña event does emerge, it will not change the long-term trajectory of rising global temperatures due to heat-trapping greenhouse gases in the atmosphere."

According to the WMO, the past nine years have marked the warmest on record, even amid a multi-year La Nina period that lasted from 2020 to early 2023. The most recent El Nino event, which emerged in June 2023 and peaked between November 2023 and January 2024, was "one of the five strongest on record" before dissipating -- although some impacts continued.

"For the past three months, neutral conditions have prevailed – neither El Nino nor La Nina. But we have still seen widespread extreme weather conditions, including intense heat and devastating rainfall," Saulo said.

She said seasonal forecasts for El Nino and La Nina and the associated impacts on the climate patterns globally are an "important tool" to inform early warnings and early action.