What are El Niño and La Niña and how do they affect Mexico?

The Doctor in Atmospheric Sciences Graciela Binimelis de Raga belongs to the Department of Atmospheric Sciences of the Institute of Atmospheric Sciences and Climate Change of the UNAM, in a recent interview for El Siglo de Torreón she addressed the impacts that these phenomena have on rainfall and drought affecting Mexico.

He described that the El Niño and La Niña phenomena occur on an interannual scale because in some years the former affects Mexico much more than in others and its effect is very significant, especially on rainfall in the north of the country.

El Niño is a natural phenomenon that consists of the warming of the Pacific Ocean, which has implications for the world’s climate and hydrology; La Niña, on the other hand, is the cold phase.

Once El Niño occurs, temperatures in the Pacific are higher than the 30-year average; while in La Niña they are lower than average.

Both phenomena affect precipitation and temperature in many regions of the planet through teleconnections, “it is not a close connection in a place where the anomaly or high temperature with respect to the average is occurring, but very distant impacts are seen. “Because in the north you (Coahuila) don’t even have a coast on the Pacific and in this way we have to understand that the climate is very complex.”

He points out that the maximum El Niño occurred in December 2023 and has now retired.

Its effects were less precipitation throughout Mexico, except in the northwest due to cold fronts that are more abundant and affect El Niño.

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It specifies that the climate system is transitioning to the La Niña phase, whose maximum phase will also be in December, “it represents for Mexico greater rainfall on the one hand, on the other hand it represents a greater number of tropical cyclones in the basin, in the North Atlantic and in the Caribbean. and the Gulf of Mexico”.

Although the conditions of both phenomena can last a couple of years, it is La Niña that brings rain to northern Mexico, “obviously when the rains are as intense as we have seen they can also cause havoc.”