Climatologists warn that the superposition of global warming effects on a rare El Niño, not observed since the late 1990s, could generate weather patterns for which science lacks sufficient data to model. The current El Niño is the first in nearly 30 years to be caused by abnormal warming of the eastern, rather than central, Pacific Ocean, meaning the entire experience of the past three decades of observations is inapplicable to what is unfolding now.

The first alarm bells rang back in the 2023–2024 season, when, contrary to expectations, the southern US states failed to experience a wet season, while the northern states failed to experience a dry one. A team from the US National Center for Atmospheric Research (NCAR) discovered the cause: the slow warming of tropical waters in the Indian and Atlantic Oceans offset the El Niño effect on North America, disrupting a once-reliable pair of linked climate patterns—the teleconnection. “We know much less about teleconnections in the new atmosphere,” Eran Vos, a climate scientist at Bar-Ilan University (Israel), told Nature, adding that the distorted synergy between global warming and El Niño behavior will not only complicate forecasting but also make it more difficult to prepare for the consequences.

Vos and his colleagues analyzed historical meteorological data and discovered a systematic breakdown in previous patterns. The warming that El Niño generated in South Asia and northeast Africa between 1960 and 1990 has since reversed—these regions now experience lower temperatures during El Niño events. In Western Europe, the cold snaps previously associated with El Niño have given way to consistently warm seasons.

For 2026, the climate scientist predicts a further worsening of the situation, including more intense winter storms in Northern Europe, droughts in Asia, and extreme precipitation in East Africa.

Ecosystem researcher Sergio de Miguel from the University of Lleida (Spain) compared the 2023 event to the complex “butterfly effect” of teleconnections, where events at one point on the planet generate multiple secondary effects thousands of kilometers away. NCAR Senior Research Scientist Clara Dezer put the problem bluntly: “Historical precedent can no longer serve as a reliable guide for ENSO teleconnections as anthropogenic warming patterns intensify.” Other impacts of the 2023–2024 El Niño corroborate her words—the Amazon drought was the worst in Brazil in 120 years.

The practical implications for weather services and governments are stark: disaster preparedness plans built on 20th-century statistics may be focusing on the wrong regions and the wrong threats.

Google machine translated