The effects of each La Niña event vary depending on its intensity, duration, time of year it develops, and the interaction with other climate drivers. Picture: Armand Hough Independent Newspapers
A new update from the World Meteorological Organization (WMO) shows that there was a 60% chance of La Niña conditions emerging towards the end of this year.
Latest forecasts from WMO Global Producing Centres of Long-Range Forecasts indicate a 55% likelihood of a transition from the current neutral conditions (neither El Niño nor La Niña) to La Niña conditions during September to November this year.
The WMO yesterday said this likelihood increased to 60% from October this year to February next year, with the chance of El Niño redeveloping during this time being negligible.
Celeste Saulo, WMO secretary-general, said that since June last year, people had seen an extended streak of exceptional global land and sea surface temperature.
“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,” Saulo said.
The past nine years have been the warmest on record even with the cooling influence of a multi-year La Niña from 2020 to early last year. The 2023-24 El Niño event started emerging in June last year and peaked in November last year to January this year as one of the five strongest on record before dissipating, although some impacts continued.
“For the past three months, neutral conditions have prevailed – neither El Niño nor La Niña. But we have still seen widespread extreme weather conditions, including intense heat and devastating rainfall,” Saulo said.
“This is why the Early Warnings for All initiative remains WMO’s top priority. Seasonal forecasts for El Niño and La Niña and the associated impacts on the climate patterns globally are an important tool to inform early warnings and early action.”
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, such as winds, pressure and rainfall. The effects of each La Niña event vary depending on its intensity, duration, time of year it develops, and the interaction with other climate drivers.
Generally, La Niña produces the opposite climate impacts to El Niño, especially in tropical regions.
However, naturally occurring climate events such as La Niña and El Niño events were said to be taking place in the broader context of human-induced climate change, which was increasing global temperatures, exacerbating extreme weather and climate, and impacting seasonal rainfall and temperature patterns.
Meanwhile, the much-anticipated State of the Climate in 2023 report was released by the National Oceanic and Atmospheric Administration last month.
The chief researcher at the CSIR, Dr Sandy Thomalla, in collaboration with 14 contributing authors, led the Southern Ocean section of the chapter on Antarctica and the Southern Ocean.
Thomalla and her collaborators assessed the 2023 anomalies (relative to climatology) in key physical and biological Southern Ocean metrics. She said the results for last year were intriguing, given the record-low sea ice coverage that has recently elicited wide media coverage and may reflect alterations in the underlying processes that determine the state of sea ice.
This analysis revealed substantial ocean warming, with mostly positive anomalies evident in sea-surface temperatures, ocean heat content and air-sea heat flux. These changes may be exacerbated by the warm conditions of the 2023 El Niño, with evidence of impacts on the ocean’s biochemistry.
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