There is no more iconic year in the history of the Western hemisphere, no clearer then-and-now dividing line, than 1492, when Columbus sailed the ocean blue and the Old World arrived on the shores of the New. On the far side of that chronological line lay what American science writer Charles Mann described in 1491, his sweeping look at the reality of indigenous American societies. Next Mann turned his attention to the near side in 1493—to the beginning of the planet’s most significant biological moment since the death of the dinosaurs.
The bare bones of the so-called Columbian Exchange have long been familiar to schoolchildren, even if teachers have understandably emphasized some parts over others: tomatoes, tobacco and syphilis to the Old World; people, horses and smallpox to the New. But as 1493 demonstrates, the exchange wasn’t even close to being a limited meeting of flora and fauna. Faster than light in terms of the history of Earth, the Columbian Exchange is still ongoing: 17-cm New Zealand flatworms only began devouring European earthworms (and thereby degrading soil quality) in the 1960s. Life on the planet seems to be returning to the days of the single supercontinent Pangaea 250 million years ago: globalization, as it turns out, is as much a biological as an economic phenomenon.
The impact, though, was at its most brutal in the beginning. The first European outbreak of syphilis—a virulent and mortal disease in its earliest incarnations—was in 1494, just two years after Columbus’s landing. Smallpox, the most terrible of the Old World killers, crossed the Atlantic in 1518. Having wrought destruction in Eurasia over millennia, it did similar damage in America in the span of mere decades, during which perhaps three-quarters of the indigenous inhabitants died.
When large-scale human movement began, most individuals involved over the next two centuries were African slaves. In the course of slaving in Africa, Europeans had picked up—and transported to the New World—diseases like malaria and yellow fever (to which Africans had partial resistance) that made the warmer parts of the Americas as deadly to Europeans as Old World diseases had made the entire hemisphere for its indigenous people. Of the first European settlements, in fact, almost all faced massive die-offs: the English sent 7,000 people to Jamestown in the two decades after its 1609 founding, 80 per cent of whom died of disease, starvation or incompetence. The colonists were barely hanging on when they stumbled over the first global commodity craze: tobacco.
Where the newcomers could secure something wanted back home—such as Aztec and Incan gold and silver—they rapidly founded way stations along a network that crossed the Pacific as well as the Atlantic. The violence-wracked boom town of Manila became the centre of a trade that saw the Spanish exchange American silver (and potatoes and corn) for Chinese silk and porcelain. That trade seriously destabilized Ming-dynasty China, putting its entire currency supply in the hands of foreigners, encouraging poor rice farmers to take to lightly populated hillsides to grow hardier American crops, provoking deforestation, overpopulation and ecological damage: the dynasty was gone within a century.
All the disruption was soon amplified by the Little Ice Age (c. 1550 to 1750 in the Northern hemisphere), the arrival of which may not have been as coincidental as once thought. Indigenous Americans controlled forest growth by burning on a scale only recently appreciated. After the mortality brought by the Columbian Exchange, far fewer people set far fewer fires and more trees grew. Both changes reduced the carbon dioxide in the atmosphere. For some experts, that reversal of current fossil-fuel burning and deforestation activities inevitably triggered the opposite of today’s global warming—global cooling.
Columbus, by not so much finding a new world as literally creating one, kick-started an astonishing and chaotic collision of life forms—from viruses to crops to people—that rapidly brought about previously unknown riches and misery. And with them, the modern world.