All the meteorological agencies in the world are looking at the same building on the east coast of the United States. On Thursday, May 14, before markets open, in College Park, Maryland, a room full of oceanographers and meteorologists will discuss a four-page pdf.
In that pdf it will be written the future of the planet. It sounds epic, but it’s more prosaic than it seems. It will not be written clearly, sharply, or with absolute certainty: but it will be.
What’s in that PDF? NOAA’s Climate Prediction Center (CPC) publishes the second Thursday of each month your ENSO Diagnostic Discussion. It is the most important report from the global El Niño monitoring systems and, from what the models are saying, the probability of a “very strong” El Niño is going to exceed 25% (and growing).
But if it’s monthly… why is this specific report important? Because the index the agency uses to monitor and predict ENSO has changed. Until this year, NOAA I used ONI: an index to measure the sea surface temperature anomaly, but which does not discount the average anomaly produced by climate change.
What is expected is that the predictions under the new index (I’ll call it RONI) is significantly less than under normal conditions. If the magnitudes shoot up despite the correction, things will look worse. This report is important because it is the first that will capture the “acceleration” of El Niño at full capacity.
What would this entail? Each new NOAA report translates into a cascade of decisions in agricultural, energy, fishing and fire policies. He last major El Niño (2023-24) coincided with 2023 would be the second warmest year on record and 2024 the warmest ever: a strong 2026-27 El Niño could push 2027 to another global record and the impacts are not well measured.
It is true that between March and May the reliability of ENSO forecasts drops sharply (because the equatorial Pacific anomalies go through their transition phase); but, in the absence of the June report, this is the best clue we have.
What can we expect? We already know that there is a 61% chance that El Niño will be with us between May and July 2026. A 25% chance that it is “very strong.” The important thing to keep in mind is what that means.
61% measures the probability that the equatorial Pacific crosses the threshold of what we understand as El Niño. But, unfortunately, it does not measure how much it will rain in Cádiz, nor what will happen to the crops in Misiones, nor how many hurricanes the Yucatán will see.
It is worth remembering that, during the warm phase (that is, during El Niño), the absence of strong trade winds that cool the surface of the equatorial Pacific causes the temperature of that area of the ocean to skyrocket. It is this, through different atmospheric teleconnectionswhich disrupts all the weather systems in the world. What we are not clear about is exactly how.
The effects are varied and change depending on the region (“drier conditions than normal in certain parts of the world; while in others it causes more precipitation. Some countries have to deal with major droughts and others with torrential rains”, says AEMET); but when we talk about temperatures there is no doubt: El Niño is synonymous with heat.
Everything else remains to be written.
Image | Xataka
In Xataka | “It is so extreme that it is difficult to believe”: El Niño forecasts depict an event of unprecedented intensity.
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