Where cacao grows and why only there

Cacao needs consistent warmth — roughly 21–32°C year-round, with no frost ever — high humidity, well-distributed rainfall of around 1,500mm or more, and shelter from wind. It grows as an understorey tree, so it also wants shade, at least when young.

Those conditions occur in a belt about twenty degrees north and south of the equator. Outside it, cacao either dies in a cold snap or fails to set pods. There is no temperate cacao and there will not be.

Cacao is native to the Amazon basin, yet West Africa now grows most of the world's crop. That is a colonial transplantation: Amelonado material moved to São Tomé and then to Ghana and the Gold Coast in the nineteenth century, where it found ideal conditions and a smallholder farming structure that scaled.

So the modern map reflects trade history at least as much as agronomy. Ivory Coast and Ghana together grow well over half the global crop from beans that originated four thousand miles away.

Hawaii is the only US state that grows cacao commercially, sitting at around 19–20°N — near the northern edge, which limits yields and makes the crop expensive. Similar edge cases exist in Taiwan, southern India and parts of Australia.

These margins matter for a reason beyond curiosity: climate projections suggest the suitable belt will shift, and some of today's major producing areas in West Africa are expected to become less suitable within decades. That is the structural pressure sitting behind current cacao prices.