La Niña increases the risk of drought in some regions, as happened in California in 2022
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A weak La Niña climate pattern has emerged in the Pacific Ocean, a month later than originally predicted. This will increase the risk of droughts and heavy rains in some parts of the world, even as it lowers global average temperatures.
The eastern tropical Pacific Ocean swings from warm to cold and back again in a temperature cycle known as the El Niño Southern Oscillation (ENSO), and is the cool phase of the La Niña cycle. It’s normal It happens every three to five years when the trade winds strengthen, which pushes colder water westward off the coast of South America.
Sea surface temperatures have been cooler than average for months, but have not fallen below the threshold required to declare a La Niña event. until nowAccording to the US National Oceanic and Atmospheric Administration (NOAA). Wind patterns also reflect La Niña conditions.
The agency predicts La Niña will continue into April 2025 before temperatures return to neutral conditions.
Although this is a weak event, cooler than average sea surface temperatures are expected to have an impact on global weather patterns, increasing risks. drought in some parts of North and South America and heavy rainfall in Australia and Southeast Asia.
La Niña also tends to lower global average temperatures, although this cooling effect is proportional to the strength of the event, he says. Pedro DiNezio at the University of Colorado Boulder. Temperatures have cooled as the mild El Niño gave way to neutral conditions and now La Niña, but DiNezio says they remain above average in much of the world.
It’s the same with the oceans. The shift to La Niña means that temperatures in the eastern tropical Pacific are cooler than average. But global sea surface temperatures stay more than 0.5°C above average
“The oceans in particular slowed down because of the record warmth that developed in mid-to-late 2023,” he said. Karin Gleason At a press conference held in December before La Niña was officially announced at NOAA.
It is not unusual for La Niña to appear this late, even after a strong El Niño event. But the change comes a month later than predicted by the forecasters. It is not clear exactly why predictions were so far off, and human-caused climate change played a role in the delay.
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