The La Niña weather phenomenon will arrive later this year, following the record-breaking heat caused by the El Niño phenomenon a year ago, bringing cooler temperatures with it.
“The 2023/24 El Nino phenomenon, which has contributed to rising global temperatures and extreme weather around the world, appears to be coming to an end. A return to La Nina conditions is likely later this year, according to the World Meteorological Organization.
According to the Organization, which believes that “the risk of El Niño recurrence is negligible in this period”, the probability of La Niña occurring in the July-September period increases to 60%, and to 70% for the August-November period.
For June through August, the Agency estimates a high chance (50%) of conditions being neutral—neither El Niño nor La Nina—or transitioning to La Nina.
What is the natural phenomenon of La Nina?
The La Nina phenomenon consists of a large-scale retreat of ocean surface temperatures in the central and eastern Pacific to the equatorial zone. Associated with changes in atmospheric circulation in the tropical zone: Wind, atmospheric pressure and rain.
During the occurrence of the event, the sea surface temperature in the eastern equatorial part of the central Pacific Ocean is 3-5°C below normal. At least 5 months remain after La Nina occurs. It has widespread weather effects throughout the world, especially in North America. It can even affect the Atlantic and Pacific hurricane seasons, with more tropical cyclones occurring in the Atlantic basin due to lower wind shear and sea surface warming, while tropical cyclogenesis is reduced in the Pacific.
However, the exact impact of the phenomenon varies depending on its intensity, duration, time of year and interactions with other climate events, the UN agency notes.
The impact also varies by region. In the tropics, La Niña produces more climatic effects than El Niño.
However, natural climate events “occur in the context of human-induced climate change, which is increasing current global temperatures, exacerbating extreme weather and climate events, and affecting seasonal patterns of rainfall and temperature,” World Meteorology notes.
El Niño heat records and La Niña cyclones
A new record high temperature has been recorded every month since June 2023 – and 2023 was the hottest year on record.
“The end of El Nino does not mean a long-term pause in climate change, as our planet will continue to warm due to emissions of heat-trapping greenhouse gases. “Extremely high sea surface temperatures will continue to play an important role in the coming months,” said Mr Barrett, deputy secretary-general of the World Meteorological Organization.
Thus, the La Nina phenomenon is included in the forecasts of the US National Oceanic and Atmospheric Administration (NOAA) for the 2024 North Atlantic hurricane season, which is expected to begin in early June and be exceptional and span four years. Seven Category 3 or greater hurricanes, according to NOAA.
The World Meteorological Organization recalls that from 2020 to the beginning of 2023, despite the cooling effect of the La Niña phenomenon, the last nine years were the warmest on record. As for El Niño, it peaked in December 2023 and was one of the five strongest episodes. have happened. “Our weather is still more extreme because of the extra heat and moisture in our atmosphere,” notes Joe Barrett.
“This is why the Alert for All initiative remains a priority for the World Health Organization.” The UN Organization has made it a priority task to cover the world’s population with an early warning system for meteorological hazards by the end of 2027, paying special attention to the most degraded areas such as Africa.