The end of La Niña: what the end of a three-year-long phenomenon means

After three years of uninterrupted occurrence, the La Niña phenomenon ends and ushers in a “neutral” period.

In an interview with Sputnik, Argentine climatologist Leandro Díaz considered that the end of La Niña could alleviate the Southern Cone drought.

The climate phenomenon of La Niña – characterized by the presence of cold waters in the Pacific Ocean – has begun to dissipate, as warned by the International Research Institute for Climate and Society, after three consecutive years of being present.

The climatologist and researcher at Argentina’s National Council for Scientific and Technical Research (Conicet) commented to Sputnik that in recent months temperatures in the Tropical Pacific became “normal” after remaining colder than usual since mid-2020.

“If one looks at how the sea surface temperature in this region is in the records, we could say that it is no longer in La Niña conditions,” Diaz assured.

The expert explained that the episode is considered present “when temperatures are 0.5°C below normal in a fairly large region.”

The climate scientist clarified that La Niña cannot yet be given as officially over since these phenomena are measured by quarters.

Thus, it will only end at the end of the first quarter, in the last days of March.

He also indicated that, although the temperature in the Pacific has already dropped, “the atmosphere still has a La Niña type behavior”.

According to the expert, it is “a matter of time” before the temperature drops in the Pacific waters, and the drop will be replicated in the atmosphere’s temperature.”

The continuity of La Niña between 2020 and 2023 is considered by the World Meteorological Organization (WMO) as the first triple La Niña episode so far in the 21st century and the third in the last 70 years.

Diaz explained that it is usual for the phenomenon to occur for two consecutive years but not three.

“It has happened on other occasions, but it is not what happens often,” he said.

Among the significant effects of the phenomenon were the intense droughts that occurred in the Southern Cone and persisted over time.

Diaz clarified that the forecast for the coming months “is quite uncertain” due to the difficulty in predicting behavior in times of “neutral conditions” of the oceans.

However, he ventured as a distant scenario that the droughts would last much longer.

The “neutral” conditions, as experts call the periods not crossed by La Niña or El Niño, would extend until the beginning of the austral spring, according to regional forecasts.

At that time, a new El Niño season would begin, characterized by a warm phase of the climatic pattern, where Pacific waters present higher temperatures than usual.

The researcher agreed with this forecast and predicted an end of the year with more rainfall and higher temperatures.

With information from Sputnik