The Atlantic Slave Trade

Europeans turned to West and Central Africa for labor because American indigenous populations had collapsed from disease and warfare after 1492, and European workers could not be forced across an ocean in the numbers planters wanted. African kingdoms and merchants already ran established slave-trading networks along the coast, so European traders plugged into an existing system rather than inventing one, trading guns, cloth and metal goods for captives taken in wars and raids further inland.

The trade grew century by century. In the 1500s it was a trickle, mostly Spanish and Portuguese, feeding early sugar colonies. By the 1600s and especially the 1700s, volume exploded as English, French and Dutch traders joined, and sugar plantations in Brazil and the Caribbean demanded constant replacement labor because conditions there killed enslaved workers faster than they could reproduce. Of roughly 12.5 million people forced onto ships, about 10.7 million survived the Middle Passage; the missing 1.8 million died from disease, starvation, violence and suicide in the holds. Brazil received about 40 percent of all arrivals, the Caribbean most of the rest, and what became the United States only around 5 percent.

Inside Africa, coastal kingdoms like Dahomey and the Asante shifted from occasional slave trading to economies built around supplying captives, using European firearms to raid neighbors and capture more people, which fed a cycle of violence. Because traders preferred young men for plantation labor, two centuries of this trade skewed sex ratios and age structures in affected regions, draining labor and reshaping political power well before European colonization of Africa's interior began in the 1800s.