The Pacific Ocean is like a vast orchestra, where each point on the map is a musician. Usually they play out of tune: somewhere it warms, somewhere it cools, and the overall picture resembles noise. But every few years, the instruments suddenly begin to sound in unison, and then droughts, floods, and heatwaves strike across the globe. This phenomenon is called El Niño, and it always catches people off guard.
For a long time, scientists could not predict El Niño in advance because their models went blind every spring. Then, at the Potsdam Institute for Climate Impact Research, they came up with the idea of monitoring not the ocean itself, but the air above it. They placed 207 points across the Pacific and began measuring how synchronously the temperature changes at these points. When the points start behaving alike, it means the orchestra is tuning up, and a storm is about to break.
Such an early forecast gives people time to prepare. Farmers can plant different crops, builders can reinforce dams, and rescue teams can pre-position equipment in vulnerable areas. For now, the method cannot predict how strong El Niño will be, but scientists are already working on that. If they succeed, we will be able to hear the storm coming a year ahead and stop fearing its sudden blow.
An average El Niño raises the global temperature anomaly by about 0.1°C. If a strong event develops in late 2020, 2021 could become a new record year for temperature, since the atmospheric response lags by three months.
The idea of predicting global catastrophes from barely perceptible signs echoes Kim Stanley Robinson's novel "Forty Signs of Rain," where scientists try to convince politicians of an impending climate shift based on early indicators.