A La Nina would have significant consequences for global agriculture because it typically brings wetter weather to eastern Australia and southeast Asia and drier conditions to the Americas.
| Photo Credit: Ritu Raj Konwar/The Hindu

There are early signs that a La Nina weather event may form in the Pacific Ocean later this year, Australia’s weather bureau said on Tuesday.

A La Nina would have significant consequences for global agriculture because it typically brings wetter weather to eastern Australia and southeast Asia and drier conditions to the Americas.

The bureau said it had declared a “La Nina Watch”.

“When La Nina Watch criteria have been met in the past, a La Nina event has subsequently developed around 50% of the time,” it said.

Also Read | El Niño, La Niña and changing weather patterns 

La Nina events result from cooler sea surface temperatures in the Pacific. Warmer sea surface temperatures can cause an opposite weather phenomenon called El Nino, which occurred last year and lasted into early 2024.

“Sea surface temperatures in the central Pacific have been steadily cooling since December 2023,” the bureau said.

“The Bureau’s modelling suggests that ENSO will likely remain neutral until at least July 2024,” it said, using the formal name, the El Niño Southern Oscillation, that describes the switch between the two phases.

Japan’s weather bureau has said there is a 90% chance that the El Nino phenomenon will dissipate by the end of May.

Other forecasters have also heralded a La Nina later this year. Last week, Japan’s weather bureau said there was a 60% chance it would occur by November, and a U.S. government forecaster said there was a 69% chance that it would develop during July-September.

Pea plants are damaged by drought, due to the El Nino weather phenomenon in Madrid municipality near Bogota, Colombia, January 17, 2016.
| Photo Credit: Reuters

Latin American nations must be on high alert as the weather phenomenon known as El Nino rapidly switches over to La Nina, experts said on Thursday, leaving populations and crops little time to recover.

El Nino and its abundant rains could soon turn into droughts caused by La Nina as well as an intense hurricane season across South America, experts said at a panel organized by the United Nations’ Food and Agriculture Organization (FAO).

The full weather pattern involving El Nino, La Nina and a neutral phase typically lasts between two to seven years. But experts said that the transition period from El Nino to La Nina is getting shorter.

“We just saw it happen,” said Yolanda Gonzalez, director of the International Research Center for the El Nino Phenomenon. “A year ago we came out of a Nina, and in March there were already signs of a Nino.”

“Now in March, April there are signs of a Nina,” she added. “We haven’t been able to recover from the impact.”

In South America, the weather patterns can hit key crops such as wheat and corn, denting commodity-dependent economies.

The phenomenon is not caused by climate change, FAO’s technical team told Reuters, but experts have seen that the effects of the weather pattern, such as rainfall, heat waves and drought, have become more extreme.

The rapid transitions between El Nino and La Nina could also be correlated with climate change, FAO said, though scientists have yet to establish definitive causation.

“These abrupt changes, and the fact that these cycles are now almost overlapping, ultimately decreases the ability to adapt to the changes,” said Marion Khamis, FAO’s regional risk management specialist. “This implies a huge challenge.”