Latin America | El Niño: Seeing it coming is not enough

El Niño is a bit like that friend who, no matter how well we think we know them, never stops surprising us. We know it will return: it is a cyclical phenomenon, though not one with a fixed periodicity, occurring every two to seven years and disrupting temperatures and rainfall patterns across the globe. But knowing it is coming does not mean knowing what its impact will be. The same warming of the Pacific can bring more rain to some areas, drought and heat to others, with very different effects depending on the time of year.

South America is a good example of this heterogeneity. In Argentina, El Niño typically increases rainfall in agricultural regions, boosting soybean and corn yields, although it also raises localized flood risks. In Colombia, the effects are almost the opposite: less rainfall and higher temperatures hurt the agricultural sector and reduce water availability, with consequences for the country’s power generation mix as well. Peru adds another dimension: it matters whether the warming is concentrated in the central Pacific or off its coast and, crucially, whether it coincides with the dry or rainy season.

This diversity is also likely to increase as climate change progresses. Although there is no firm scientific consensus that global warming is increasing the frequency or magnitude of El Niño’s temperature fluctuations, there is stronger evidence that a warmer atmosphere and warmer oceans can amplify the associated rainfall anomalies: even more extreme rainfall in some places and more severe droughts in others.

The point is that, to understand climate risk, seeing it coming is not enough; we increasingly need to take a closer look. National averages can conceal important differences across regions; annual averages can mask differences across seasons; and sector-level averages can obscure differences among crops or activities. It is not enough to know how much rainfall Colombia will lose. We need to know where and when that decline will occur, and which crops, reservoirs, or infrastructure will be most exposed.

This granular analysis also matters because the damage is not predetermined by the severity of the climate event. Risk depends on the climate hazard itself, but also on how much is exposed to it—population, physical capital, potential income—and on the degree of vulnerability, including a lack of capacity to adapt. This is where societies and public authorities have room to act: more resilient infrastructure, efficient water management, early-warning systems, adaptation measures, and improved crop varieties. Ultimately, technological development and investment can help mitigate the physical hazards unleashed by an exceptionally strong El Niño.

If El Niño is inevitable and its effects may intensify in a warmer world, the response cannot be limited to trying to predict the next episode. We need to reduce vulnerability by looking more closely so we can act more effectively.

Press article. Published in El País on October 4, 2026.