Columbian exchange

The Columbian exchange, also known as the Columbian interchange, was the widespread transfer of plants, animals, and diseases between the New World (the Americas) in the Western Hemisphere, and the Old World (Afro-Eurasia) in the Eastern Hemisphere, from the late 15th century on. It is named after the explorer Christopher Columbus and is related to the European colonization and global trade following his 1492 voyage. Some of the exchanges were deliberate while others were unintended. Communicable diseases of Old World origin resulted in an 80 to 95 percent reduction in the Indigenous population of the Americas from the 15th century onwards, and their near extinction in the Caribbean.

The cultures of both hemispheres were significantly impacted by the migration of people, both free and enslaved, from the Old World to the New. European colonists and African slaves replaced Indigenous populations across the Americas, to varying degrees. The number of Africans taken to the New World was far greater than the number of Europeans moving there in the first three centuries after Columbus.

The new contacts among the global population resulted in the interchange of many species of crops and livestock, which supported increases in food production and population in the Old World. American crops such as maize, potatoes, tomatoes, tobacco, cassava, sweet potatoes, and chili peppers became important crops around the world. Old World rice, wheat, sugar cane, and livestock, among other crops, became important in the New World.

The term was first used in 1972 by the American historian and professor Alfred W. Crosby in his environmental history book The Columbian Exchange. It was rapidly adopted by other historians and by journalists.

In 1972, Alfred W. Crosby, an American historian at the University of Texas at Austin, published the book The Columbian Exchange, thus coining the term. His primary focus was mapping the biological and cultural transfers that occurred between the Old and New Worlds. He studied the effects of Columbus's voyages between the two – specifically, the global diffusion of crops, seeds, and plants from the New World to the Old, which radically transformed agriculture in both regions.

His research made a lasting contribution to the way scholars understand the variety of contemporary ecosystems that arose due to these transfers. His 1986 book Ecological Imperialism presented further research in the field.

The scientific consensus is that humans first came to the New World from Siberia thousands of years ago. There is little additional evidence of contacts between the peoples of the Old World and those of the New World, although the literature speculating on pre-Columbian trans-oceanic journeys is extensive. The first inhabitants of the New World brought with them small domestic dogs and, possibly, a container, the calabash, both of which persisted in their new home. The medieval explorations, visits, and brief residence of the Norsemen in Greenland, Newfoundland, and Vinland in the late 10th century and 11th century had no known impact on the Americas, though the small perennial Rumex acetosella (sheep's sorrel) appeared in Greenland at that time.

Many scientists accept that possible contact between Polynesians and coastal peoples in South America around the year 1200 resulted in genetic similarities and the adoption by Polynesians of an American crop, the sweet potato. However, it was only with the first voyage of the Italian explorer Christopher Columbus and his crew to the Americas in 1492 that the Columbian exchange began, resulting in major transformations in the cultures and livelihoods of the peoples in both hemispheres.