Iñigo Gómara

On a meadow in Laqueuille, perched at 1040 meters in the Massif Central, grass doesn't grow at the whim of weather but follows a schedule set by the ocean thousands of kilometers away. From 1959 to 2015, the PaSim pasture model, fed with hourly weather data from the SAFRAN archive, simulated grass growth while excluding pests and farmer interventions. What remained was a pure climatic signal.

Every year, the same drama unfolds over West Africa: from June to September, the sky fills with moisture and releases rains that determine the harvests of millet, sorghum, and maize. This rainy season is driven by the West African monsoon, a giant atmospheric pump that pulls moist air from the ocean deep into the continent.

Every year, over the semi-arid belt south of the Sahara, the sky stages the same play: gentle rains that nourish millet, and violent downpours that wash away villages. Until recently, both acts were attributed to a single conductor: ocean surface temperature. But if you listen closely, each rain has its own control panel.