La arrival of La Niña is finally here, but it’s not going to stick around for long

A weak La Niña weather pattern has emerged in the Pacific Ocean several months later than originally expected. Although this will reduce average global temperatures, it will increase the risk of droughts and heavy rains in parts of the world.

The eastern tropical Pacific Ocean transitions from hot to cold and back again in a temperature cycle known as El Niño Southern Oscillation (ENSO). La Niña is the cold phase of the cycle. It typically occurs about every three to five years when trade winds strengthen, pushing cold water westward from off the coast of South America.

Sea surface temperatures in that part of the Pacific Ocean have been below average in recent months, but never below the threshold needed to declare a La Niña event. Until nowaccording to the National Oceanic and Atmospheric Administration (NOAA). Wind patterns also now reflect La Niña conditions.

The agency expects La Niña to last until April 2025, before temperatures return to normal.

Even as a weak event, below-average sea surface temperatures are expected to have a unique impact on global weather patterns, increasing the risk of drought in parts of North and South America and torrential rain in Australia and the Southeast. has been. Asia.

He also notes that La Niña events tend to lower global average temperatures, and that this cooling effect is proportional to the strength of the event. Pedro Dinegio At the University of Colorado Boulder. Dinezio said the transition from warm El Niño conditions to neutral La Niña conditions has brought temperatures down, but they are still above average in many parts of the world.

That also applies to the ocean. A transition to La Niña means temperatures in the eastern tropical Pacific Ocean are colder than average. However, global sea surface temperatures are still rising 0.5℃ or more Above average.

“The oceans, in particular, were record warm and slow to cool in mid-to-late 2023,” he said. Karin Gleeson He spoke at a press conference at NOAA in December, before La Niña officially occurred.

It is not unusual for a La Niña event to occur this late, even after a strong El Niño event. But that change will occur several months later than forecasters expected. It remains unclear why predictions were so far off and whether anthropogenic climate change played a role in the delay.