Imagine having two thermometers placed in different locations. One measures how much ocean temperature is "fidgeting," while the other tracks how tightly different points on the planet are linked. In the spring of 2022, both thermometers showed the same thing: El Niño was on its way. That is the name for the warm current in the Pacific that alters weather worldwide.

The first method looks at "disorder" in temperature: if it starts fluctuating more than usual, El Niño is approaching. The second method notices that points in the ocean begin to "coordinate" with each other, as if exchanging signals. When both methods agree, you can say with near certainty that the warm current will arrive.

Thanks to such early warning, people gain a whole year to prepare: stockpile water, reinforce homes, and replant crops. Previously, El Niño was detected only a few months ahead, leaving almost no time for preparation.