One answer would be: a world bound together by hoops of Spanish silver. Silver from the Americas is well on its way to doubling or tripling the world’s stock of precious metals. Potosí, in what is now southern Bolivia, is the main source—the biggest, richest strike in history. Begin the cruise here, at this central node in the network. Located more than thirteen thousand feet up the Andes, Potosí sits at the foot of an extinct volcano that is as close to a mountain of pure silver as geology allows. Around it is an almost treeless plateau, strewn with glacial boulders, scoured by gelid winds. Agriculture struggles here, and there is no wood for fire. Nonetheless, by 1642 this mining city had become the biggest, densest community in the Americas.
Potosí is a brawling, bawling boomtown marked by extravagant display and hoodlum crime. It is also a murderously efficient mechanism for the extraction and refining of silver ore in appallingly harsh conditions. Indian workers haul the ore on their backs up crude ladders from hundreds of feet below the surface, then extract the silver by mixing the ore with highly toxic mercury. Smelters on the slopes transform the metal into bars of almost pure silver, typically weighing sixty-five pounds and stamped with sigils guaranteeing their quality and authenticity. Other silver is stamped into coins—the Spanish peso is on its way to becoming a de facto world currency, as the U.S. dollar is today. Battalions of llamas—more sure-footed and altitude tolerant than mules and horses—carry the coins and bars down from the mountains, every dangerous step guarded by men with weapons. They hoist the silver onto ships in Arica, on the Chilean coast, which shuttle it to the great port of Lima, seat of the Spanish colonial government. From Lima the silver is loaded onto the first of a series of military convoys that will transport it across the world.
From the plane, follow the silver fleet as it travels north. To the east of the convoy rise the Andean slopes, gripped in ecological turmoil. Humankind has lived here for many thousands of years, erecting some of the world’s first urban complexes in the valleys north of Lima. A hundred and fifteen years before this overflight, smallpox swept in. After it came other European diseases, and then Europeans themselves. Millions died, fearful and suffering, in shattered mountain villages. Now, decades later, slopes terraced and irrigated for centuries remain empty. Shrubs and low trees have overwhelmed abandoned farms. A huge volcanic eruption in 1600 covered central Peru with up to three feet of ash and rubble. Four decades later, little has been cleared away. Andean ecosystems have gone feral. Sailing north, the silver fleet is passing something akin to wilderness, at least in patches.
Some of the vessels anchor in Panama, while others go to Mexico. Watching from the plane, observe that the Panamanian silver crosses the isthmus, bound for Europe, whereas most of the Mexican silver is bound ultimately for Asia. How much goes where is the subject of brisk dispute, both by customs officials in 1642 and by historians today. The Spanish monarchy, perpetually hungry for cash, wants the silver in the home country. Spanish colonists want to send as much as possible to China—coins and bars can be traded there more profitably than anywhere else. The tension leads, inevitably, to smuggling. Official statistics suggest that no more than a quarter of the silver went across the Pacific. In the past historians have largely assumed that government scrutiny kept the smuggling to perhaps 10 percent of the total, meaning that the official statistics were roughly correct. A new wave of researchers, however, argues that smuggling was rampant; China sucked up as much as half of the silver. The debate is more than pedantic. One side regards European expansion as the primary motivating force in world affairs; the other views the earth as a single economic unit largely driven by Chinese demand.
Follow the Europe-bound silver as it is carried by mule train over the mountains to Portobelo, then Panama’s main Caribbean port. Guarded by an armada of galleons, bristling with guns and crewed by as many as two thousand seamen and soldiers, the silver traverses the Atlantic every summer, its departure timed to avoid hurricane season. The convoy bellies up to the mouth of the Guadalquivir, Spain’s only major navigable river, and then sixty miles upstream to Seville.
Unloaded onto the quays, the chests of treasure are the emblem of a paradox: silver from the Americas has made the Europe of 1642 affluent and powerful beyond its giddiest fantasy. But Europe itself is plagued from one end to the other by war, inflation, rioting, and weather calamities. Turmoil is nothing new in Europe, which is divided by language, culture, religion, and geography. But this is the first time that the turmoil is intimately linked to human actions on opposite ends of the earth. Trouble volleys from Asia, Africa, and the Americas to Europe, shuttling about the world on highways of Spanish silver.
Cortés’s conquest of Mexico—and the plunder that came from it—threw Spain’s elite into delirium. Enraptured by sudden wealth and power, the monarchy launched a series of costly foreign wars, one overlapping with another, against France, the Ottoman Empire, and the Protestants in the Holy Roman Empire. Even as Spain defeated the Ottomans in 1571, discontent in the Netherlands, then a Spanish possession, was flaring into outright revolt and secession. The struggle over Dutch independence lasted eight decades and spilled into realms as far away as Brazil, Sri Lanka, and the Philippines. Along the way, England was drawn in; raising the ante, Spain initiated a vast seaborne invasion of that nation: the Spanish Armada. The invasion was a debacle, as was the fight to stop rebellion in the Netherlands.
War spawned war. In 1642, Spain is combating secession in Andalusia, Catalonia, and Portugal, which it has ruled for six decades; France is fighting Spain on its northern, eastern, and southern borders; and Swedish armies are battling the Holy Roman Empire. (Emperor Ferdinand III, the son-in-law of one Spanish king and the father-in-law of another, is so closely allied with Spain that he has often been called a Spanish puppet.) Almost the only European nation not directly or indirectly at war with Spain is England, which is convulsed by its own civil strife—the ascetic Puritan rebellion that will soon lead to civil war and the execution of the king.
The costs are staggering. At the height of the Vietnam War, the United States fielded about 500,000 soldiers. If the U.S. had wanted to send out the same proportion of its men that Spain did in its war with the Dutch, according to Dennis Flynn, an economic historian at the University of the Pacific, it would have had to send 2.5 million. “Even though all this silver was coming in from Bolivia, Spain didn’t have enough money to pay its army in the Netherlands,” he told me. “So the men mutinied constantly. I did a count once—there were forty-five mutinies between 1572 and 1607. And that was just one of Spain’s wars.”
To pay for its foreign adventures, the court borrowed from foreign bankers; the king felt free to incur debts because he believed they would be covered by future shipments of American treasure, and bankers felt free to lend for the same reason. Alas, everything cost more than the monarch hoped. Debt piled up hugely—ten or even fifteen times annual revenues. Nonetheless the court continued to view its economic policy in the optative mood; few wanted to believe that the good times would end. The inevitable, repeated result: bankruptcy. Spain defaulted on its debts in 1557, 1576, 1596, 1607, and 1627. After each bankruptcy, the king borrowed more money. Lenders would provide it—after all, they could charge high interest rates (Spain paid up to 40 percent, compounded annually). For obvious reasons the high interest rates made the next bankruptcy more likely. Still the process continued—everyone believed the silver would keep pouring into Seville. Now, in 1642, so much silver has been produced that its value is falling even as the mines slacken. The richest nation in the world is hurtling toward financial Armageddon. Europe is complexly interconnected; Spain’s economic collapse is dragging down its neighbors.
The silver trade was not the only cause of this tumult—religious conflict, royal hubris, and struggles among classes all were important—but it was an essential part. The flood of precious metal unleashed by Cortés so vastly increased Spain’s money supply that its small financial sector could not contain it. It was as i
f a billionaire suddenly deposited a fortune into a tiny country bank—the bank would immediately redeposit the cash into other, bigger institutions that could do something with it. American silver overflowed from Spain like water from a bathtub and washed into bank vaults in Italy, the Netherlands, and the Holy Roman Empire. Payments for Spanish military adventures filled coffers across the continent.
Economics 101 predicts what will happen in these circumstances. New money chases after the same old goods and services. Prices rise in a classic inflationary spiral. In what historians call a “price revolution,” the cost of living more than doubled across Europe in the last half of the sixteenth century, tripling in some places, and then rose some more. Because wages did not keep pace, the poor were immiserated; they could not afford their daily bread. Uprisings of the starving exploded across the continent, seemingly in every corner and all at once. (Researchers have called it the “general crisis” of the seventeenth century.)
Hope for the peasantry was provided by American crops, which by 1642 have ridden the silver route across the Atlantic. As the plane sweeps over Europe, it descends low enough for passengers to view the marks of the Columbian Exchange: plots of American maize in Italy, carpets of American beans in Spain, fields crowded with the shining, upturned visages of American sunflowers in France. Big tobacco leaves soak up sunlight on Dutch farms; tobacco is so common in Catholic Europe that Pope Urban VIII has this year denounced its use (in Protestant England, it is endorsed even by the nation’s most notorious killjoy, Oliver Cromwell). Most important will be the potato, which is beginning to fill bellies in Germany, the Netherlands and, increasingly, Ireland. In ordinary times, the quickly increasing agricultural productivity would soothe some of the discontent caused by inflation and war. But these are not ordinary times: the plane’s instruments reveal that the climate itself has been changing.
For almost a century Europe has experienced frighteningly snowy winters, late springs, and cold summers. Frigid Mays and Junes delay French wine harvests until November; people walk a hundred miles across the frozen sea from Denmark to Sweden; Greenland hunters moor their kayaks on the Scottish shore. After three failed harvests, Catholic mobs in Ireland rise up, robbing and killing the hated English Protestants—attacks those Protestants use as an opportunity to seize Catholic land. Fearing that growing Alpine glaciers will overrun their homes, Swiss villagers induce their bishop to exorcise a threatening ice front—an echo of the Spaniards in Santo Domingo, seeking God’s help against the plague of ants. Annual visits from the bishop drive back the glacier by eighty paces. The order of the world seems overturned.
Historians call the freeze the Little Ice Age. Enduring from about 1550 to about 1750 in the Northern Hemisphere, this global thermal anomaly is difficult to pin down; its onset and duration differed from one region to the next. Because few people then kept written records of weather conditions, paleoclimatologists (researchers of ancient climate) must study it with imperfect measures like the thickness of tree rings and the chemical composition of tiny bubbles of gas in polar ice. Based on such indirect evidence, some researchers proposed that the Little Ice Age was attributable to a decline in the number of sunspots known as the Maunder Minimum. Because sunspots are correlated with the sun’s energy output, fewer sunspots implies less-intense solar irradiation—enough, these researchers argued, to cool the earth. Other scientists theorized that the temperature drop was due to big volcanic eruptions, which blast sulfur dioxide into the upper atmosphere. High above the clouds, the sulfur dioxide mixes with water vapor to form minute droplets of sulfuric acid—shiny motes in the sky—that reflect some of the sun’s light into space. This phenomenon existed in 1642; a massive eruption in the southern Philippines the year before is now thought to have cooled the earth for as long as three years. Both hypotheses have drawn sharp criticism, though. Many scientists believe that the impact of the Maunder Minimum was too small to account for the Little Ice Age. Others argue that a series of individual volcanic eruptions could not have caused a steady temperature drop.
In 2003, William F. Ruddiman, a paleoclimatologist at the University of Virginia, suggested a different cause for the Little Ice Age—an idea that initially seemed outlandish, but that is increasingly treated seriously.
As human communities grow, Ruddiman pointed out, they open more land for farms and cut down more trees for fuel and shelter. In Europe and Asia, forests were cut with the ax. In the Americas before Colón, the primary tool was fire—vast stretches of it. For weeks on end, smoke from Indian bonfires shrouded Florida, California, and the Great Plains. Today, many researchers believe that without regular burning, much of the midwestern prairie would have been engulfed by an invading tide of trees. The same was true for the grasslands of the Argentine pampas, the hills of Mexico, the Florida dunes, and the high plains of the Andes.
American forests, too, were shaped by flame. Indians’ “frequent fiering of the woods,” remarked English colonist Edward Johnson in 1654, made the forests east of the Mississippi so open and “thin of Timber” that they were “like our Parkes in England.” Annual fire seasons removed scratchy undergrowth, burned out noxious insects, and cleared land for farms. Scientists have conducted fewer studies of burning in the tropics, but two California paleoecologists (scientists who study past ecosystems) surveyed the fire history of thirty-one sites in Central and South America in 2008 and found that in every one the amount of charcoal in the soil—an indicator of fire—had increased substantially for more than two thousand years.
Enter now the Columbian Exchange. Eurasian bacteria, viruses, and parasites sweep through the Americas, killing huge numbers of people—and unraveling the millennia-old network of human intervention. Flames subside to embers across the Western Hemisphere as Indian torches are stilled. In the forests, fire-hating trees like oak and hickory muscle aside fire-loving species like loblolly, longleaf, and slash pine, which are so dependent on regular burning that their cones will only open and release seed when exposed to flame. Animals that Indians had hunted, keeping their numbers down, suddenly flourish in great numbers. And so on.
Indigenous pyromania had long pumped carbon dioxide into the air. At the beginning of the Homogenocene the pump suddenly grows feeble. Formerly open grasslands fill with forest—a frenzy of photosynthesis. In 1634, fourteen years after the Pilgrims land in Plymouth, colonist William Wood complains that the once-open forests are now so choked with underbrush as to be “unuseful and troublesome to travel through.” Forests regenerate across swathes of North America, Mesoamerica, the Andes, and Amazonia.
Ruddiman’s idea was simple: the destruction of Indian societies by European epidemics both decreased native burning and increased tree growth. Each subtracted carbon dioxide from the air. In 2010 a research team led by Robert A. Dull of the University of Texas estimated that reforesting former farmland in American tropical regions alone could have been responsible for as much as a quarter of the temperature drop—an analysis, the researchers noted, that did not include the cutback in accidental fires, the return to forest of unfarmed but cleared areas, and the entire temperate zone. In the form of lethal bacteria and viruses, in other words, the Columbian Exchange (to quote Dull’s team) “significantly influenced Earth’s carbon budget.” It was today’s climate change in reverse, with human action removing greenhouse gases from the atmosphere rather than adding them—a stunning meteorological overture to the Homogenocene.
Flying the plane back across the Atlantic, the effects of the Little Ice Age are obvious in the Americas, too. Clearly visible from the air is the filling in of Indian lands by forest—and by snow. Ice is solid enough that people ride carriages on Boston harbor; it freezes over most of Chesapeake Bay, and nearly wipes out the two score French colonists who this year have founded Montreal. Introduced cattle and horses die in snowdrifts in Maine, Connecticut, and Virginia. Other impacts are harder to see. The forests are filling in former Indian lands with cold-loving species like hemlock, spruce, and beech
. Vernal pools take longer to evaporate in the canopy they provide in these cool summers. Mosquitoes that breed in those pools thus have an increased chance for survival.
Using fire, indigenous people in the Americas cleared big areas for agriculture and hunting, as shown in this map of North America’s eastern seaboard.
Click here to view a larger image.
European diseases caused a population crash across the hemisphere—and an extraordinary ecological rebound as forests filled in abandoned fields and settlements. The end of native burning and the massive reforestation drew so much carbon dioxide from the air that an increasing number of researchers believes it was a main driver of the three-century cold snap known as the Little Ice Age.
Click here to view a larger image.
Among these paradoxically cold-loving mosquitoes is Anopheles quadrimaculatus, the overall name for a complex of five near-indistinguishable sibling species. Like other Anopheles mosquitoes, A. quadrimaculatus hosts the parasite that causes malaria—the insect’s common name is the North American malaria mosquito. Southeast England at this time is rampant with malaria. Precise documentation will never become available, but there is good reason to suspect that by 1642 malaria has already traveled in immigrant bodies from England to the Americas. A single bite into an infected person is enough to introduce the parasite to its mosquito host, which spreads the parasite far and wide. Virginia and points south have already proven so unhealthy for Europeans that plantation overseers are finding it difficult to persuade laborers to come from overseas to work in the tobacco fields.
Some landowners already have resolved this problem by purchasing workers from Africa. Partly driven by the introduction of malaria, a slave market is beginning to quicken into existence, a profitable exchange that will entwine itself over time with the silver market. As ever, the ships from Africa will form a kind of ecological corridor, through which travel passengers not on any official manifest. Crops like yams, millet, sorghum, watermelon, black-eyed peas, and African rice will follow the slave ships to the Americas. So will yellow fever.