Book review of “1493 Uncovering the new world Columbus Created”

[ This book will be included in the “must read” category of my giant booklist when I get around to updating it.

This book isn’t just about the past, the implications reverberate into the postcarbon future. Will slavery return without fossil slaves? What will a lack of pesticides and natural gas fertilizer (there’s not enough poop to replace it) do to agricultural production? Will the world’s population shift a lot more to those who have a natural immunity to malaria and yellow fever once these diseases come rip roaring back? Mann argues that natural rubber is essential to civilization, artificial rubber can’t substitute for many needs. It’s likely pests will make rubber trees scarce again, how will that affect future societies?

Alice Friedemann www.energyskeptic.com author of “When Trucks Stop Running: Energy and the Future of Transportation”, 2015, Springer and “Crunch! Whole Grain Artisan Chips and Crackers”. Podcasts: Derrick Jensen, Practical Prepping, KunstlerCast 253, KunstlerCast278, Peak Prosperity , XX2 report ]

Charles Mann. 2011. 1493 Uncovering the New World Columbus Created. Random House.

The main theme is that natives and newcomers in the Americas, Europe, and Asia interacted in unexpected ways, creating biological bedlam. This is one of the best books I’ve ever read plus interesting and well written. There are new perspectives on slavery, and reasons for why the West ended up dominating the rest of the world (beyond what was written in Jared Diamond’s book “Guns, Germs, and Steel”.)

There are 3 main parts

The Atlantic, where the most important effects were caused by microscopic imports to the Americas (initially the diseases that depopulated Indian societies, then malaria and yellow fever, which encouraged plantation slavery
The Pacific, where the major introductions were American food crops, which both helped sustain a population boom and led indirectly to massive environmental problems.
How environmental historians have increasingly come to believe that the Columbian Exchange played a role in the agricultural revolution of the 18^th century and the industrial revolution of the 19^th. Both occurred first in Europe, and so this ecological phenomenon had large-scale political and economic implications—it fostered the rise of the West.

These are my kindle notes, a small fraction of the book, and it’s a bit disjointed since the paragraphs that segue from one topic to the next are left out. Since I copy only new information that interests me, I’ve left out quite a bit you might be interested in. I hope what’s below entices you to read the entire book.

The 300-year-long Little Ice Age was caused by tens of millions of natives killed by European diseases who were no longer torching of the landscape to farm it

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, 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. Rather than paving roads, Indians used fire to make what the ecological historian Stephen J. Pyne has called “corridors of travel. Well-used paths could be six feet wide, hundreds of miles long, and cleared completely of brush and stones.

Scientists have conducted fewer studies of burning in the tropics, but two California paleoecologists (scientists who study past ecosystems) surveyed the fire history of 31 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 2000 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.

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.

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, 14 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.

Colonists destroyed native food supplies and ecology

Except for defensive palisades, Powhatan farmers had no fences around their fields. Why screen off land if no cattle or sheep had to be kept inside? The English, by contrast, regarded well-tended fences as hallmarks of civilization, according to Virginia D. Anderson, a historian at the University of Colorado at Boulder. Fenced fields kept animals in; fenced woodlots kept poachers out. The lack of physical property demarcation signified to the English that Indians didn’t truly occupy the land—it was, so to speak, unimproved. Equally unfamiliar was the Powhatan practice of scattering their farm plots within larger cleared areas. To the Indians, fallow lands were a kind of communal larder, a place for naturally occurring useful plants, including grains (little barley, sumpweed, goosefoot), edible greens (wild lettuce, wild plantains), and medicinals (sassafras, dogbane, smartweed). Because none of these species existed in Europe, the English didn’t know the groundcover was useful. Instead they saw “unused” land, something that bewildered them. How could Indians go to the trouble of clearing the land but then not use it?

English waterways ran swiftly in the spring, scouring away the soil from steep banks, then turned to dribbling trickles in July and August. Beyond the riverbanks the land was drier; one could hike for miles in summer without stepping into mud. Chesapeake Bay was, by contrast, a seemingly endless patchwork of bogs, marshes, grassy ponds, seasonally flooded meadows, and slow-moving streams. It seemed to be wet everywhere, no matter what the season. Credit for the watery environment belongs to the American beaver (Castor canadensis), which had no real English equivalent. Weighing as much as sixty pounds, these big rodents live in dome-shaped lodges made by blocking streams with mud, stones, leaves, and cut saplings—as many as 20 dams per mile of stream. The dams smear the water across the landscape, so to speak, transforming a rushing rivulet into a series of broad pools and mucky wetlands linked by shallow, multiply branched channels. Indians regarded this as a fine thing—easier to take a canoe through a set of ponds than a narrow, quick-flowing stream. English accounts, by contrast, are filled with descriptions of colonists unhappily stumbling through the sopped countryside.

The freshwater marshes favored the growth of tuckahoe (Peltandra virginica, arrow arum), a semi-aquatic plant found in stands throughout the eastern United States and Canada. Tuckahoe has a bulb-like, underground rhizome (enlarged stem area used for storage) that every spring sends out a thin stalk with a long leaf shaped like a child’s sketch of an arrowhead. It was a standing larder for the people of Tsenacomoco, always ready in the springtime if they exhausted the maize from the previous fall.

At first imported pigs, goats, cattle and horses didn’t fare well, not least because they were eaten by starving colonists. But during the peace after Pocahontas’s marriage, they multiplied. Colonists quickly lost control of them. Indians woke up to find free-range cows and horses romping through their fields, trampling the harvest. If they killed the beasts, gun-waving colonists demanded payment. Animal numbers boomed for decades. The worst may have been the pigs. By 1619, one colonist reported, there were “an infinite number of Swine, broken out into the woods.” Smart, strong, and constantly hungry, they ate nuts, fruits, and maize, turning up the marshy soil with their shovel-like noses in search of edible roots. One of these was tuckahoe, the tuber Indians relied upon when their maize harvests failed. Pigs turned out to like tuckahoe—a lot. Traveling through the area in the eighteenth century, the Swedish botanist Peter Kalm found that pigs were “very greedy” for the tubers, “and grow very fat by feeding on them.” In places “frequented by hogs,” he argued, tuckahoe “must have been extirpated.” The people of Tsenacomoco found themselves competing for their food supply with packs of feral pigs.

The English imported bees for honey, not to help their crops—pollination wasn’t discovered until the mid-eighteenth century—but feral honeybees pollinated farms and orchards anyway. Without them, many of the plants Europeans brought with them wouldn’t have proliferated.

So critical to European success was the honeybee that Indians came to view it as a harbinger of invasion; the first sight of a bee in a new territory, the French-American writer Jean de Crèvecoeur noted in 1782, “spreads sadness and consternation in all minds.

Removing forest cover, blocking regrowth on fallow land, exhausting the soil, shutting down annual burning, unleashing big grazing and rooting animals, introducing earthworms, honeybees, and other alien invertebrates—the colonists so profoundly changed Tsenacomoco that it became harder and harder for its inhabitants to prosper there. Meanwhile, it was easier and easier for Europeans to thrive in an environment that their own actions were making increasingly familiar.

Causes of slavery in America

One of the mosquitoes that can grow in the cold 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 it does today, malaria played a huge role in the past—a role unlike that of other diseases, and arguably larger. When Europeans brought smallpox and influenza to the Americas, they set off epidemics: sudden outbursts that shot through Indian towns and villages, then faded. Malaria, by contrast, became endemic, an ever-present, debilitating presence in the landscape. Socially speaking, malaria—along with another mosquito-borne disease, yellow fever—turned the Americas upside down. Before these maladies arrived, the most thickly inhabited terrain north of Mexico was what is now the southeastern United States, and the wet forests of Mesoamerica and Amazonia held millions of people. After malaria and yellow fever, these previously salubrious areas became inhospitable. Their former inhabitants fled to safer lands; Europeans who moved into the emptied real estate often did not survive a year.

The malaria parasite, a superbly canny creature, can hide in the liver for as long as five years, periodically emerging to produce full-blown malarial relapses. Falciparum is one of the most deadly forms of malaria, because falciparum alters red blood cells so much they stick to the walls of the tiny capillaries inside the kidneys, lungs, brain, and other organs. This hides the infected cells from the immune system but slowly cuts off circulation as the cells build up on the capillary walls like layers of paint on an old building. Untreated, the circulation stoppage leads to organ failure, which kills as many as one out of ten falciparum sufferers. Vivax doesn’t destroy organs, and thus is less deadly. But during its attacks sufferers are weak, stuporous, and anemic: ready prey for other diseases.

Falciparum, the most deadly variety of malaria, is also the most temperature sensitive. Around 72°F it hits a threshold; the parasite needs three weeks at this temperature to reproduce, which approaches the life expectancy of its mosquito host; below about 66°F it effectively cannot survive. Vivax, less fussy, has a threshold of about 59°F.

Malaria’s precise date of arrival will always lie in the realm of speculation. What is clear is that malaria rapidly made itself at home in Virginia. It became as inescapable there as it was in the English marshes—a constant, sapping part of life. When London investors shipped people to Virginia, Governor George Yeardley warned in 1620, they “must be content to have little service done by new men the first year till they be seasoned”—seasoning being the term for the period in which newcomers were expected to battle disease.

Indentured servants are by far more satisfactory than slaves. They speak the same language, conform to the same social norms, and know European farming methods. Since their contracts are limited in time, there’s little reason to run away.

Slaves make unsatisfactory workers. Because they were usually from distant cultures, they often didn’t speak their owners’ language and could be so unfamiliar with their owners’ societies that they would have to be trained from scratch (Africans, for example, knew only tropical forms of agriculture). Worse, they had every incentive to escape, wreak sabotage, or kill their owners, the people who were depriving them of liberty.

Because willing hands are more likely to do their jobs well, Smith reasoned in The Wealth of Nations, “the work done by freemen comes cheaper in the end than that performed by slaves.

Of all the nations in western Europe, moreover, England would be the last that one would expect to take up this especially brutal form of bondage, because opposition to slavery was more common there than the rest of Europe. If the continent had an antislavery culture, in fact, it was England. This was less a tribute to the nation’s moral advancement than an enraged response to the constant targeting of her ships by Barbary pirates, who from the 16^th to 18^th century enslaved tens of thousands of English sailors, soldiers, and merchants.

Based in northwest Africa, these Muslim corsairs prowled as far north as the English Channel, ransacking seaside villages and seizing ships at anchor; in just ten days, the mayor of Plymouth complained in 1625, buccaneers lurking outside the harbor took 27 vessels. Most English captives were sent to the galleys; many were forcibly converted to Islam; others disappeared into slave caravans bound across the deserts to Ottoman Egypt or sub-Saharan Africa.

Slavery had been widespread in England in medieval times, as it was in the rest of Europe. In England, though, it became exceptional—not actually illegal, but rare—for political reasons, for the economic reasons described by Smith, and because slavery as an institution had little appeal in a nation with mobs of unemployed workers.

As a consequence, the English colonies initially turned to indentured servants and largely avoided slaves. Indentured servants comprised between a third and a half of the Europeans who arrived in English North America in the first century of colonization. Slaves were rare—only 300 lived in of Virginia in 1650.

Then, between 1680 and 1700, the number of slaves suddenly exploded. Virginia’s slave population rose in those years from three thousand to sixteen thousand—and kept soaring thereafter. In the same period the tally of indentured servants shrank dramatically.

What accounts for this about-face? Economists and historians have mulled it over for decades. Adam Smith predicted in The Wealth of Nations that laborers would see the available land around them and leave their jobs, “in order to become landlords themselves.” They would hire other workers in turn, who would “soon leave them for the same reason they left their first master.

If employers constantly lost workers to the lure of cheap land, then they would want to restrict their freedom of movement. Bondage was the inevitable end result. Paradoxically enough, America’s wide-open frontier was, from this perspective, an incitement to slavery.

At the very time the supply of desperate Scots was increasing the colonists turned to captive Africans—people who couldn’t speak the language, had no wish to cooperate, and cost more to transport. Why?

Indian slaves. The female slaves of Indians provided sexual services to honored male visitors (a gesture frequently misunderstood by Europeans, who thought that the Indians were offering their wives).

Economically speaking, indigenous slavery was a good deal for both natives and newcomers. In the Charleston market Indians sometimes could sell a single slave for the same price as 160 deerskins. “One slave brings a Gun, ammunition, horse, hatchet, and a suit of Clothes, which would not be procured without much tedious toil a hunting,” a Carolina slave buyer noted, perhaps with some exaggeration, in 1708. “The good prices The English traders give them for slaves Encourages them to this trade Extremely. “Good prices” from the Indian point of view, but cheap to the English. Indian captives cost £5–10, as little as half the price of indentured servants,

The annual cost of ownership of slaves was much lower than indentured servants, because slaves did not have to be released after a few years—the purchase price could be amortized over decades.

Colonists chose Indian slaves over European servants. A 1708 census, Carolina’s first, found 4,000 English colonists, almost 1,500 Indian slaves, and just 160 servants, the majority presumably indentured. But the Indian slave trade was immensely profitable—and very short-lived. By 1715 it had almost vanished.

Working in groups, Indian slaves proved to be unreliable, even dangerous employees who used their knowledge of the terrain against their owners. Rhode Island denounced the “conspiracies, insurrections, rapes, thefts and other execrable crimes” committed by captive Indian laborers, and banned their import. So did Pennsylvania, Connecticut, Massachusetts, and New Hampshire.

Indians were just as prone to malaria as English indentured servants—and more vulnerable to other diseases. Native people died in ghastly numbers across the entire Southeast.

Naturally, the colonists looked for a different solution to their labor needs—one less vulnerable to disease than European servants or Indian slaves. Carolina grew famous as a slave importer, a place where the slave ships arrived from Africa and the captives, dazed and sick, were hustled to auction. But for its first four decades the colony was mainly a slave exporter—the place from where captive Indians were sent to the Caribbean, Virginia, New York, and Massachusetts

Here notice a striking geographical coincidence. By 1700, English colonies were studded along the Atlantic shore from what would become Maine to what would become South Carolina. Northern colonies coexisted with Algonkian-speaking Indian societies that had few slaves and little interest in buying and selling captives; southern colonies coexisted with former Mississippian societies with many slaves and considerable experience in trading them. Roughly speaking, the boundary between these two types of society was Chesapeake Bay, not far from what would become the boundary between slave and non-slave states in the United States. Did the proximity of Indian societies with slaves to sell help grease the skids for what would become African slavery in the South? Was the terrible conflict of the U.S. Civil War a partial reflection of a centuries-old native cultural divide? The implication is speculative, but not, it seems to me, unreasonable.

The death rate of European indentured servants was simply too high. Europeans are very susceptible as can be seen by what happened to British soldiers. 19th-century parliamentary reports on British soldiers in West Africa concluded that disease killed between 48 and 67% of them every year. The rate for African troops in the same place, by contrast, was about 3%, an order-of-magnitude difference. African diseases slew so many Europeans, Curtin discovered, that slave ships often lost proportionately more white crewmen than black slaves—this despite the horrendous conditions below decks, where slaves were chained in their own excrement. To forestall losses, European slavers hired African crews.

Bigger planters had higher costs but were better insulated. Over time, they gained an edge; smaller outfits, meanwhile, struggled. Accentuating the gap, wealthy Carolinian plantation owners could afford to move to resorts in the fever-free mountains or shore during the sickness season. Poor farmers and slaves had to stay in the Plasmodium zone. In this way disease nudged apart rich and poor. Malarial places, the Rutmans said, drift easily toward “exaggerated economic polarization.” Plasmodium not only prodded farmers toward slavery, it rewarded big plantations, which further lifted the demand for slaves.

The classic southern plantation. High on a nearly treeless hill, with tall windows to admit the breeze, it was ideally suited to avoid mosquitoes and the diseases that accompanied them.

Malaria did not cause slavery. Rather, it strengthened the economic case for it. Regardless of whether they knew it, though, planters with slaves tended to have an economic edge over planters with indentured servants. If two Carolina rice growers brought in ten workers apiece and one ended up after a year with nine workers and the other ended up with five, the first would be more likely to flourish.

Slavery would have existed in the Americas without the parasite. In 1641 Massachusetts, which had little malaria, became the first English colony to legalize slavery explicitly. During the mid-18th century, the healthiest spot in English North America may have been western Massachusetts’s Connecticut River Valley, according to an analysis by Dobson and Fischer. Malaria there was almost nonexistent; infectious disease, by the standards of the day, extremely rare. Yet slavery was part of the furniture of daily life—at that time almost every minister, usually the most important man in town, had one or two. About 8% of the inhabitants of the main street of Deerfield were African slaves.

Sugar production is awful work that requires many hands. The cane is a tall, tough Asian grass, vaguely reminiscent of its distant cousin bamboo. Plantations burn the crop before harvest to prevent the knifelike leaves from slashing workers. Swinging machetes into the hard, soot-smeared cane under the tropical sun, field hands quickly splattered themselves head to foot with a sticky mixture of dust, ash, and cane juice.

Yellow fever virus kills about half of its victims—43 to 59% in six well-documented episodes McNeill compiled in Mosquito Empires. Survivors acquire lifelong immunity. In Africa yellow fever was a childhood disease that inflicted relatively little suffering. In the Caribbean it was a dire plague that passed over Africans while ravaging Europeans, Indians, and slaves born in the islands.

Slave states sought to prevent their education because would encourage them to aspire far above their station in life. Wrong ideas in the wrong people’s hands could put the elites’ political power at risk.

In malaria zones, the primary victims are children. Adults as a rule have already had the disease and become immune upon survival. The adults who have most to fear are recent arrivals—a lesson that was learned in the Americas again and again, perhaps most dramatically during the U.S. Civil War. Much of the war was fought in the South by troops from the North. Crossing the Mason-Dixon Line, Yankees broke an epidemiological barrier. The effects were enormous. In July 1861, three months after the conflict began, the Union’s Army of the Potomac marched from Washington to the Confederate capital of Richmond, Virginia. It was repulsed at what became known to Yankees as the Battle of Bull Run and to Confederates as the Battle of Manassas. After fleeing to Washington, the generals dragged their feet about further action. President Lincoln railed against their pusillanimity, but they may have had a point. In the year after Bull Run, at least a third of the Army of the Potomac suffered from what army statistics describe as remittent fever, malaria. Union troops in North Carolina fared still worse. An expeditionary force of fifteen thousand landed at Roanoke Island in early 1862, and spent much of the war enforcing a naval blockade from a fort on the coastline. The air at dusk shimmered with Anopheles quadrimaculatus. Between the summer of 1863 and the summer of 1864, the official annual infection rate for intermittent fevers was 233 percent—the average soldier was felled two times or more.

Incompetent generalship, valiant opponents, and long supply lines were partly to blame. But so was malaria—the price of entering the Plasmodium zone. During the war the annual case rate never dropped below 40 percent. In one year Plasmodium infected 361,968 troops. The parasite killed few directly, but it so badly weakened them that they succumbed readily to dysentery or measles or what military doctors then called “chronic rheumatism” (probably a strep infection). At least 600,000 soldiers died in the Civil War, the most deadly conflict in U.S. history. Most of those lives were not lost in battle.

Disease killed twice as many Union troops as Confederate bullets or shells.

Malaria also helped to stop the British army. Cornwallis estimated that only 3,800 of his 7,700 men were fit to fight, although historians like to credit victory to American leaders because of their bravery and skill. But “revolutionary mosquitoes” played an equally critical role. With Cornwallis’s troops falling to the Columbian Exchange in ever-greater numbers, the British army surrendered, effectively creating the United States, on October 17, 1781.

Today some fear that global warming will foster the spread of malaria. But if people continue destroying mosquito habitat by draining wetlands the hotter weather may have no impact on malaria rates.

How Potatoes changed history

Today the potato is the fifth most important crop worldwide, surpassed in harvest volume only by sugarcane, wheat, maize, and rice.

Compared to grains, tubers are inherently more productive. If the head of a wheat or rice plant grows too big, the plant will fall over, with fatal results. Modern plant breeders have developed wheat and rice varieties with shorter, stronger stalks that can bear heavier loads of grain. But even they could not support something as heavy as an Idaho potato.

Many scholars believe that the introduction of S. tuberosum to Europe was a key moment in history. This is because their widespread consumption largely coincided with the end of famine in northern Europe. (Maize, another American crop, played a similar but smaller role in southern Europe.) More than that, the celebrated historian William H. McNeill has argued, S. tuberosum led to empire: “[P]otatoes, by feeding rapidly growing populations, permitted a handful of European nations to assert dominion over most of the world between 1750 and 1950.” Hunger’s end helped create the political stability that allowed European nations to take advantage of American silver. The potato fueled the rise of the West.

Potatoes would not seem obvious candidates for domestication. Wild tubers are laced with solanine and tomatine, toxic compounds thought to defend the plants against attacks from dangerous organisms like fungi, bacteria, and human beings. Cooking often breaks down a plant’s chemical defenses—many beans, for example, are safe to eat only after being soaked and heated—but solanine and tomatine are unaffected by the pot and oven. Andean peoples apparently neutralized them by eating dirt: clay, to be precise. In the altiplano, guanacos and vicuñas (wild relatives of the llama) lick clay before eating poisonous plants. The toxins in the foliage stick—more technically, “adsorb”—to the fine clay particles. Bound to dirt, the harmful substances pass through the animals’ digestive system without affecting it. Mimicking this process, Indians apparently dunked wild potatoes in a “gravy” made of clay and water. Eventually they bred less lethal varieties, though some of the old, poisonous tubers still remain, favored for their resistance to frost. Bags of clay dust are still sold in mountain markets to accompany them on the table.

The effects of this transformation were so striking that any general history of Europe without an entry in its index for S. tuberosum should be ignored. Hunger was a familiar presence in the Europe of the Little Ice Age, where cold weather killed crops even as Spanish silver drove up prices. Cities were provisioned reasonably well in most years, their granaries monitored by armed guards, but country people teetered on a precipice. When harvests failed, food riots ensued; thousands occurred across Europe between 1400 and 1700, according to the great French historian Fernand Braudel. Over and over, rioters, often led by women, broke into bakeries, granaries, and flour mills and either stole food outright or forced merchants to accept a “just” price. Ravenous bandits swarmed the highways, seizing grain convoys to cities. Order was restored by violent action.

Braudel cited an eighteenth-century tally of famine in France: forty nationwide calamities between 1500 and 1778, more than one every decade. This appalling figure actually understates the level of scarcity, he wrote, “because it omits the hundreds and hundreds of local famines.” France was not exceptional; England had seventeen national and big regional famines between 1523 and 1623. Florence, hardly a poor city, “experienced 111 years when people were hungry, and only sixteen ‘very good’ harvests between 1371 and 1791”—seven bad years for every bumper year. The continent could not feed itself reliably. It was caught in the Malthusian trap.

As the sweet potato and maize did in China, the potato (and maize, to a lesser extent) helped Europe escape Malthus. When the agricultural economist Arthur Young toured eastern England in the 1760s he saw a farming world that was on the verge of a new era. A careful investigator, Young interviewed farmers, recording their methods and the size of their harvests. According to his figures, the average yearly harvest in eastern England from an acre of wheat, barley, and oats was between 1,300 and 1,500 pounds. By contrast, an acre of potatoes yielded more than 25,000 pounds

Potatoes didn’t replace grain but complemented it. Every year, farmers left fallow as much as half of their grain land, to replenish the land and fight weeds (they were plowed under in summer). Now smallholders could grow potatoes on the fallow land, controlling weeds by hoeing. Because potatoes were so productive, the effective result was, in terms of calories, to double Europe’s food supply. “For the first time in the history of western Europe, a definitive solution had been found to the food problem”.

Routine famine almost disappeared in potato country, a two-thousand-mile band that stretched from Ireland in the west to Russia’s Ural Mountains in the east. At long last, the continent could, with the arrival of the potato, produce its own dinner.

Although the potato raised farm production overall, its greater benefit was to make that production more reliable. Before S. tuberosum, summer was usually a hungry time, with stored grain supplies running low before the fall harvest. Potatoes, which mature in as little as three months, could be planted in April and dug up during the thin months of July and August. And because they were gathered early, they were unlikely to be affected by an unseasonable fall—the kind of weather that ruined wheat harvests.

In war-torn areas, potatoes could be left in the ground for months, making them harder to steal by foraging soldiers. (Armies in those days did not march with rations but took their food, usually by force, from local farmers.)

The economist Adam Smith, writing a few years after Young, was equally taken with the potato. He was impressed to see that the Irish remained exceptionally healthy despite eating little else: “The chairmen, porters, and coal-heavers in London, and those unfortunate women who live by prostitution—the strongest men and the most beautiful women perhaps in the British dominions—are said to be, the greater part of them, from the lowest rank of people in Ireland, who are generally fed with this root.” Today we know why: the potato can better sustain life than any other food when eaten as the sole item of diet. It has all essential nutrients except vitamins A and D, which can be supplied by milk;

At the same time that the sweet potato and maize were midwifing a population boom in China, the potato was helping to lift populations in Europe—the more potatoes, the more people.

The Irish, who ate more potatoes than anyone else, had the biggest boom; the nation grew from perhaps 1.5 million in the early 1600s to about 8.5 million two centuries later. (Some believed it reached 9 or even 10 million.) The increase occurred not because potato eaters had more children but because more of their children survived. Part of the impact was direct: potatoes prevented deaths from famine. The greater impact, though, was indirect: better-nourished people were less likely to die of infectious disease, the era’s main killer. Norway was an example. Cold climate had long made it vulnerable to famine, which struck nationwide in 1742, 1762, 1773, 1785, and 1809. Then came the potato. The average death rate changed relatively little, but the big spikes vanished. When they were smoothed out, Norwegian numbers soared.

Such stories were recorded all over the continent. Hard hit by the shorter growing seasons of the Little Ice Age, mountain hamlets in Switzerland were saved by the potato—indeed, they thrived.

Just as American crops were not the only cause of China’s population boom, they were not the only reason for Europe’s population boom. The potato arrived in the midst of changes in food production so sweeping that some historians have described them as an “agricultural revolution.” Improved transportation networks made it easier to ship food from prosperous areas to places with poor harvests.

Marshlands and upland pastures were reclaimed. Shared village land was awarded to individual families, dispossessing many smallholders but encouraging the growth of mechanized agriculture

Advances were not confined to agriculture. American silver let Europeans build ships to increase trade, raising living standards. Some improvements occurred in the continent’s governance and even in its abysmal hygiene standards

In 2010 two economists at Harvard and Yale attempted to account for such factors by comparing events in parts of Europe that were similar except for their suitability for potatoes; any systematic differences, they argued, would be due to the new crop. According to the two researchers’ “most conservative” estimate, S. tuberosum was responsible for about an eighth of Europe’s population increase.

Bird poop, potatoes, pesticides

The bacteria in the soil constantly digest nitrates and nitrites, turning the nitrogen back into unusable nitrogen gas.

Unlike mammalian urine, bird urine is a semisolid substance. Because of this difference, birds can build up reefs of urine in a way that mammals cannot (except, occasionally, for big colonies of bats in caves). Even among birds, though, Chincha-style guano deposits—heaps as big as a twelve-story building—are uncommon. To make them, the birds must be relatively large, form big flocks, and defecate where they live (gulls, for instance, release their droppings away from their breeding grounds). In addition, the area must be dry enough not to wash away the guano. The waters off the Peruvian coast receive less than an inch of rain a year. The Chinchas, the most important of Peru’s 147 guano islands, house hundreds of thousands of Peruvian cormorants, the most prolific guano producers. According to The Biogeochemistry of Vertebrate Excretion, a classic treatise by G. Evelyn Hutchinson, a cormorant’s annual output is about thirty-five pounds. Arithmetic suggests that the Chincha cormorants alone produce thousands of tons per year.

At the time, the best-known soil additive was bone meal, made by pulverizing bones from slaughterhouses. Bushels of bones went to grinding factories in Britain, France, and Germany. Demand ratcheted up, driven by fears of soil depletion. Bone dealers supplied the factories from increasingly untoward sources, including the recent battlefields of Waterloo and Austerlitz. “It is now ascertained beyond a doubt, by actual experiment upon an extensive scale, that a dead soldier is a most valuable article of commerce,” remarked the London Observer in 1822. The newspaper noted that there was no reason to believe that grave robbers were limiting themselves to battlefields. “For aught known to the contrary, the good farmers of Yorkshire are, in a great measure, indebted to the bones of their children for their daily bread. From this perspective, avian feces began to seem like a reasonable item of commerce.

Peru had awarded a monopoly on shipping guano internationally to a company in Liverpool. With demand outstripping supply, Peru and its British consignees were able to charge high prices. Their customers reacted with fury to what they viewed as extortion. Decrying the “powerful monopoly” on guano, the British Farmer’s Magazine laid out its readers’ demands in 1854. “We do not get anything like the quantity we require; we want a great deal more; but at the same time, we want it at a lower price.” If Peru insisted on getting a lot of money for a valuable product, the only fair solution was invasion. Seize the guano islands! From today’s perspective, the outrage—threats of legal action, whispers of war, editorials about the Guano Question—is hard to understand. But agriculture was then “the central economic activity of every nation,” as the environmental historian Shawn William Miller has pointed out. “A nation’s fertility, which was set by the soil’s natural bounds, inevitably shaped national economic success.” In just a few years, agriculture in Europe and the United States had become dependent on high-intensity fertilizer—a dependency that has not been shaken since. Britain, first to adopt guano and by far the largest user, was both the most dependent and the most resentful. Much as oil buyers today begrudge the member nations of OPEC, Peru’s British customers ranted about the guano cartel. They were apoplectic as Peru’s guano barons sauntered around Lima in the latest Parisian fashions, bejeweled trollops on their arms.

Congress passed the Guano Islands Act in 1856, authorizing its citizens to seize any guano islands they saw. The biggest loads came from Navassa, an island fifty miles west of Haiti, which the United States took in 1857.

Under the aegis of the Guano Islands Act, merchants claimed title to ninety-four islands, cays, coral heads, and atolls between 1856 and 1903. The Department of State officially recognized sixty-six as U.S. possessions. Most proved to have little guano and were quickly abandoned. Nine remain under U.S. control today.

Recall that almost four out of ten Irish ate no solid food except potatoes, and that the rest were heavily dependent on them. Recall, too, that Ireland was one of the poorest nations in Europe. At a stroke, the blight removed the food supply from half the country—and there was no money to buy grain from outside. The consequences were horrific; Ireland was transformed into a post-apocalyptic landscape. Destitute men lined the roads in their rags, sleeping in crude shelters dug into roadside ditches. People ate dogs, rats, and tree bark. Reports of cannibalism were frequent and perhaps accurate. Entire families died in their homes and were eaten by feral pets. Disease picked at the survivors: dysentery, smallpox, typhus, measles, a host of ailments listed in death records as “fever.” Mobs of beggars—“homeless, half-naked, famishing creatures,” one observer called them—besieged the homes of the wealthy, calling for alms. So many died that in many western towns the bodies were interred in mass graves.

As resources vanished, life became a struggle of all against all. Starving men stole into fields to steal turnips from the ground. Farmers dug mantraps in their fields to stop them. Landlords evicted tenants in huge numbers, tore down their homes, then went bankrupt themselves. Neighbor fought neighbor for food and shelter. Crime levels exploded, the murder rate almost doubling in two years. Some hungry people stole to put food on the table, others to be fed while incarcerated. In one case two men released from prison were sent back the next day for trying “to break into jail.” The only violent crime to decline was rape, because potential perpetrators lacked the energy.

Britain mounted the biggest aid program in its history, but it was catastrophically insufficient—largely, Irish nationalists charge, because London treated the crisis as a chance to expand its efforts to transform Ireland’s “primitive” subsistence farming to export-oriented agriculture. Instead of simply providing food, the British pulled people off the farm, massed them in workhouses, and fed them from soup kitchens; meanwhile, the farms were consolidated into bigger, more export-friendly units. Other critics point to the export of food from Ireland during the famine: 430,000 tons of grain in 1846 and 1847, the two worst years. “The Almighty indeed sent the potato blight,” nationalist leader John Mitchel thundered, “but the English created the famine.

At a million or more fatalities, it was one of the deadliest famines in history, in terms of the percentage of population lost. A similar famine in the United States today would kill almost forty million people. Only the famine of 1918–22 in the Soviet Union may have been worse.

Something about Ireland was uniquely vulnerable—but what? One part of the answer was the sheer number of potatoes, a fat target for the blight. Another part was the uniformity of the crop. According to Ó Gráda, the blight historian, about half of Ireland was dominated by a single, outstandingly productive variety: the Lumper.

Murphy had never seen the beetle before its hordes suddenly attacked his potatoes. Nor had his neighbors who also were visited by it, or the farmers in Iowa and Nebraska whom it invaded that summer. The insect marched steadily north and east, expanding its range by fifty to a hundred miles a year, shocking potato growers at every step. It reached Illinois and Wisconsin in 1864; Michigan, by 1870. Seven years later it was attacking potatoes from Maine to North Carolina. The little insects swarmed potato fields in such profusion, according to one widely repeated story, that they stopped nearby trains. Their bodies covered the tracks in a layer deep enough to make the wheels slip “as if oiled, so that the locomotive was powerless to draw the train of cars.” Strong winds blew the beetles into the sea, from which they washed ashore in a glittering, yellow-orange carpet that fouled beaches from New Jersey to New Hampshire. Farmers had no idea where the creature had come from or how to stop it from eating their potato fields to the ground.

Today it occupies a swath of Europe that reaches from Athens to Stockholm. In the Americas its realm extends from south-central Mexico to north-central Canada. Many biologists fear that it will spread into East and South Asia, completing a round-the-world journey.

A single genetic accident in a single individual was enough to generate a worldwide problem. The beetle is the potato’s most devastating pest to this day. “One of the worst features of the present visitation,” the newspaper continued, “is that the Colorado beetle is noted for its permanency, and rarely abandons localities until it has ravaged them for several seasons in succession.…

Farmers tried everything they could think of: picking off and crushing beetles with special pincers; trying to find less-attractive potato varieties; encouraging the insect’s natural predators (ladybirds, soldier beetles, certain species of tiger beetle); moving potato fields every season, thus avoiding beetles overwintering (an insect version of hibernation) in the soil; surrounding their plots with buffalo bur, “so as to concentrate the insects, and thus more readily destroy them”—

An Iowa man touted his horse-drawn beetle remover, which raked the insects into a box dragged behind. Potato growers doused plants with lime, sprinkled sulfur, spread ashes, sprayed with tobacco juice. They mixed coal tar with water and splashed that on the beetles. Some farmers reportedly tried wine. Others tried kerosene. Nothing worked.

Because growers planted just a few varieties of a single species, pests had a narrower range of natural defenses to overcome. If a species was able to adapt to the potatoes in one place, it would not have to adapt to those in others. It could simply jump from one identical food pool to the next—a task that was easier than ever, thanks to modern inventions like railroads, steamships, and refrigeration. Not only did industrial agriculture present insects with a series of rich, identical targets; these faster, denser transportation networks made it ever easier for faraway species to exploit them.

The late nineteenth century was, in consequence, a time of insect plagues. The boll weevil, slipping over the border from Mexico, wiped out so much cotton in the South that the governor of South Carolina proclaimed a day of public prayer and fasting to fight the bug. The cottony cushion scale, an Australian insect, swept through California’s citrus industry. A European import, the elm leaf beetle, ravaged elm trees in U.S. cities; Dutch elm disease, introduced from Asia despite the name, would arrive later and more or less wipe out all elms east of the Mississippi. Returning the favor, the United States exported phylloxera, an aphid that wrecked vineyards in most of France and Italy.

Paris Green’s insecticidal properties were supposedly discovered by a farmer who finished painting his shutters and in a fit of annoyance threw the remaining paint on his beetle-infested potato plants. The emerald pigment in the paint was Paris Green, made largely from arsenic and copper. Developed in the late eighteenth century, it was common in paints, fabrics, and wallpaper. Farmers diluted it heavily with flour and dusted it on their potatoes or mixed it with lots of water and sprayed. Paris Green was a simple, reliable solution: buy the pigment, mix in flour or water according to the manufacturer’s instructions, apply it with a sprinkler or dust box, and watch potato beetles die. To potato farmers, Paris Green was a godsend. To the nascent chemical industry, it was something that could be tinkered with and extended and improved. If arsenic killed potato beetles, why not try it on other pests? Why not spray Paris Green to combat cotton worm, apple cankerworm, apple codling moth, elm leaf beetle, juniper webworm, and that plague of blueberries, the northern walking stick? Arsenic killed them all. It was a godsend to cotton farmers reeling from the boll weevil.

Eager scientists and engineers invented foggers and pumpers, sprayers and dusters, pressure valves and adjustable brass nozzles. The dust changed to liquid; the copper-arsenic mix changed to a lead-arsenic mix and then a calcium-arsenic mix.

From the beginning, farmers knew that Paris Green and copper sulfate were toxic. Even before the discovery of its insecticidal properties, many people had got sick from living in homes with wallpaper printed with Paris Green. The thought of spraying food with this poison made farmers anxious. They dreaded the prospect of letting pesticides and fungicides build up in the soil. They worried about exposing themselves and their workers to dangerous chemicals. They were alarmed by the cost of all the technology. All of these fears came true, but all could be adjusted for, at least in part. For a long time, farmers didn’t know about the most worrisome issue of all: inevitably, the chemicals would stop working.

As early as 1912 a few beetles showed signs of immunity to Paris Green. Farmers didn’t notice, though, because the pesticide industry kept coming up with new arsenic compounds that kept killing potato beetles. By the 1940s growers on Long Island found themselves having to use ever-greater quantities of the newest arsenic variant, calcium arsenate, to maintain their fields.

Farmers bought DDT and exulted as insects vanished from their fields. The celebration lasted about seven years. The beetle adapted.

Potato growers demanded new chemicals. The industry provided dieldrin. It lasted about 3 years. By the mid-1980s, each new pesticide in the eastern United States was good for about a season. In what critics call the “toxic treadmill,” potato farmers now treat their crops a dozen or more times a season with an ever-changing cavalcade of deadly substances. Many writers have decried this, perhaps none more elegantly than Michael Pollan in The Botany of Desire. As Pollan observed, large-scale potato farmers now douse their land with so many fumigants, fungicides, herbicides, and insecticides that they create what are known, euphemistically, as “clean fields”—swept free of life, except for potato plants. (In addition, the crops are sprayed with artificial fertilizer, usually once a week during growing season.) If rain doesn’t fall for a few days, the powders and solutions can build up on the surface of the soil, creating a residue that resembles the aftermath of a chemical-warfare test.

Researchers believe that the chemical assault is counterproductive. Strong pesticides kill not only target species but their insect enemies as well. When the target species develop resistance, they often find their prospects better than before—everything that had previously kept them in check is gone. In this way, paradoxically, insecticides can end up increasing the number of harmful insects—unless farmers control them with yet more chemical weapons.

Blight, too, has returned. Swiss researchers were dismayed in 1981 to discover that the second type of P. infestans oomycete, previously known only in Mexico, had found its way to Europe. Because the blight was now capable of “sexual” reproduction, it had greater genetic diversity—more resources, that is, to adapt to chemical control. Similar introductions occurred in the United States. In both cases the new strains were more virulent, and more resistant to metalaxyl, the chief current anti-blight treatment. No good substitute has yet appeared. In 2009, as I was writing this book, potato blight wiped out most of the tomatoes and potatoes on the East Coast of the United States. Driven by an unusually wet summer, it turned gardens all around me into slime.

Compared to grains, potatoes have more water, which is nutritionally useless. In the past potatoes were about 22 percent dry matter; wheat, by contrast, was about 88 percent. Thus the 25,620 pounds/acre yield of potatoes found by Young was equivalent to 5,636 pounds/acre of dry matter. Similarly, wheat’s 1,440 pounds/acre yield would be 1,267 pounds/acre of dry matter. For this reason, it is fairer to say that potatoes were about four times more productive than wheat.

The historian Kenneth Pomeranz has argued that “some of the most intensely farmed soils of Europe (including in England) faced serious depletion by the early nineteenth century.” If guano had not arrived, Pomeranz believes, the consequences may not have been simply remaining at the same level but a full-scale disaster across much of the continent.

Why silver, tobacco, and sweet potatoes ultimately led to China’s downfall

There is little evidence, though, that Beijing anticipated the worst consequences. As in Europe, so much silver flooded into China that the price eventually dropped. By about 1640 silver was worth no more in China than it was in the rest of the world. At this point the Ming government was tripped up by an error it had committed decades in the past. When the court had ordered citizens to pay their taxes in silver, it had set up the tax rolls in terms of the weight of silver people had to pay, not its value. As with Spain, the taxes were not indexed for inflation. As with Spain, the same amount of tax was worth less money when the price of silver dropped. The Ming dynasty had a revenue shortfall. Not having paper currency, the government couldn’t print more money—deficit spending was impossible. Suddenly it couldn’t pay for national defense. It was a bad time to run out of money for the military: China was then under assault by the belligerent northern groups now called Manchus. According to William Atwell, a historian at Hobart and William Smith Colleges, the Chinese government’s dependence on the silver trade helped push it over the edge. The takeover by the Manchus—they became the Qing dynasty—took decades and was bloody even by the tough standards of Chinese history. Nobody knows how many millions died.

Atwell’s contentions have been vigorously debated, yet there is little doubt that China’s entry into the galleon trade had consequences of a sort rarely discussed in freshman economics textbooks. Flynn and Giráldez point out that China devoted a big fraction of its productive base to acquiring the silver needed for commerce and government. For hundreds of years, China produced silk, porcelain, and tea to acquire a commodity, silver, which was needed to replace the paper notes that the government had made valueless. It was as if to buy a newspaper for a dollar one first had to make and sell something else to get the dollar banknote. Actually, it was worse: the silver stocks had to be constantly replenished, incurring further costs, because the metal was constantly worn away as it passed from hand to hand. (Paper money wears out, too, but costs next to nothing to replace.)

China’s tobacco addiction occurred in an entirely different context, and thus had an entirely different impact. N. tabacum was part of an unplanned ecological invasion that shaped, for better and worse, modern China. At the time, China had roughly a quarter of the world’s population, which had to provide for itself on roughly a twelfth of the world’s arable land. Both figures are imprecise at best, but there is little dispute that the nation has long had a lot of people and that it always has had relatively little land to grow crops to feed them. In practical terms, China had to harvest huge amounts of food—half or more of the national diet—from areas with enough water to grow rice and wheat. Unluckily, those areas are relatively small. The nation has many deserts, few big lakes, irregular rainfall, and just two major rivers, the Yangzi and the Huang He (Yellow). Both rivers run long, looping courses from the western mountains to the Pacific coast, emptying into the sea scarcely 150 miles from each other. The Yangzi carries mountain runoff into the rice-growing flats near the end of its course. The Huang He takes it into the North China Plain, then as now the center of Chinese wheat production. Both areas are vital to feeding the nation; there are no other places in China like them. And both are prone to catastrophic floods.

Song and Yuan, Ming and Qing—every dynasty understood both this vulnerability and the concomitant necessity of maintaining China’s agricultural base by controlling the Yangzi and Huang He. So important was water management that European savants like Karl Marx and Max Weber identified it as China’s most important institution. Creating and operating huge, complex irrigation systems, Weber claimed, required organizing masses of laborers, which inevitably created a powerful state bureaucracy and subjugated the individual.

“No large group of the human race in the Old World was quicker to adopt American food plants than the Chinese,” Alfred W. Crosby wrote in The Columbian Exchange. Sweet potatoes, maize, peanuts, tobacco, chili peppers, pineapple, cashew, manioc (cassava)—all poured into Fujian (via the galleon trade), Guangdong (the province southwest of Fujian, via Portuguese ships in Macao), and Korea (via Japan, which took them from the Dutch). All became part of the furniture of Chinese life—who can imagine Sichuan (Szechuan) food today without heaps of hot peppers? “While men who stormed Tenochtitlan with Cortés still lived,” Crosby said, “peanuts were swelling in the sandy loams near Shanghai; maize was turning fields green in south China; and the sweet potato was on its way to becoming the poor man’s staple in Fujian.

Sweet potatoes in China are often eaten raw, the skin whittled off in a fashion that makes them somewhat resemble ice cream cones.

The 1580s and 1590s, an intense point in the Little Ice Age, were two decades of hard cold rains that flooded Fujianese valleys, washing away rice paddies and drowning the crop. Famine shadowed the rains. Poor families were reduced to eating bark, grass, insects, and even the seeds found in wild-goose excrement.

To deny supplies to the Ming/wokou, the Qing army forced the coastal population from Guangdong to Shandong—the entire eastern “bulge” of China, a 2,500-mile stretch of coastline—to move en masse into the interior. Beginning in 1652, soldiers marched into seaside villages and burned houses, knocked down walls, and smashed ancestral shrines; families, often given only a few days’ warning, evacuated with nothing but their clothes. All privately owned ships were set afire or sunk. Anyone who stayed behind was slain. “We became vagrants, fleeing and scattering,” one Fujianese family history recalled. People “simply went in one direction until they halted,” another said. “Those who did not die scattered over distant and nearby localities.” For three decades the shoreline was emptied to a distance inland of as much as fifty miles. It was a scorched-earth policy, except that the Qing scorched the enemy’s earth, not their own.

For almost 2,000 years, China’s numbers had grown very slowly. That changed in the decades after the violent Qing takeover. From the arrival of American crops at the beginning of the new dynasty to the end of the eighteenth century, population soared. Historians debate the exact size of the increase; many believe the population roughly doubled, to as much as 300 million people. Whatever the precise figure, the jump in numbers had big consequences. It was the demographic surge that transformed the nation into a watchword for crowding.

About the time that the Spaniards arrived in Manila sweet potatoes were displacing native crops like yam, sago, and banana. As had the Chinese, islanders were using sweet potato’s high yields and tolerance of bad soil to move into highland areas that had been lightly settled before. New Guinea was so transformed that some archaeologists speak of an “Ipomoean revolution.” Still, the impact in China was bigger, if only because China is so big, and because the country had a centralized government that could enforce policies that spread sweet potato.

Were maize, potatoes, and sweet potatoes entirely responsible for China’s population boom? No. American plants arrived as the Qing were transforming China. Ambitious on many fronts, the dynasty fought disease and hunger, the nation’s two major killers, by enacting a program, the world’s first, of smallpox inoculation; expanding a nationwide network of granaries that bought surplus grain and sold it at low, state-controlled prices during shortages; and implementing what were, for the era, sophisticated disaster-relief programs (some were as simple as a halt in the collection of grain levies in famine-struck areas). At the same time, the Qing campaigned against the nation’s traditional population-control method: female infanticide. Many Chinese men had spent their days as bachelors, because infanticide removed women from the population. Now more could marry and have babies; now their babies were less likely to die from smallpox and starvation. Now, too, farm families were less likely to be driven into penury by the state: the Kangxi emperor promised in 1713 that the dynasty would never raise the basic tax on cropland, even though it was making massive investments in transportation networks so that farmers could sell their harvests, raising their incomes. Happily, those harvests were likely to grow; the Little Ice Age was waning.

Still, as noted by Lan, the Sichuan historian, most of the increase took place in the areas with American crops. The families that Qing policies encouraged to move west needed to eat, and what they ate, day in and day out, was maize, potatoes, and sweet potatoes. Part of the reason China is the world’s most populous nation is the Columbian Exchange.

New roads built by the Chinese to help merchants ship rice and wheat from places with abundant harvests to places that needed supplies. Instead smallholders discovered they could make more money by switching from rice and wheat to sugarcane, peanuts, mulberry trees, and, most of all, tobacco. Initially the Qing court cracked down on this shift, insisting that peasant farmers practice “correct agriculture”—that is, grow rice and wheat. “Tobacco is not healthy for the people,” the Yongzheng emperor proclaimed in 1727. “Because cultivating tobacco requires using rich land, its cultivation is harmful for growing grain.” But as the court grew more insular and debased—seemingly the fate of all Chinese dynasties—it lost interest in enforcing agricultural correctness. Farmers seized their opportunity. Tobacco required four to six times more fertilizer and twice as much labor as rice, but was more profitable; China’s growing battalions of nicotine addicts were willing to pay more for their pipes than their food.

Tobacco appeared in almost every corner in China, according to Tao Weining, an agricultural historian in Guangdong. And it was a big presence in those places: in two typical hilly areas examined by Tao, “nearly half” of the total farmland was devoted to N. tabacum. In consequence, the local price of rice doubled, as did the price of most common vegetables and fruits. Farmers ended up spending their tobacco profits on food expensively imported from other parts of China. As in Virginia, tobacco drained the land. When farmers exhausted the soil from one former rice paddy, they went to the next. And when they ran out of rice paddies, they went into the hills. The same phenomenon is still occurring today.

At the edge of the village a sign proclaimed that China Tobacco, a state monopoly, had contracted with Yongding’s farmers to convert their paddies to tobacco. The company had built a new road to facilitate harvest. From atop the terraces we looked down on horizontal arcs of splayed, fleshy green arrows: N. tabacum.

In Yongding, the villagers had replaced some of the lost rice with maize, shoving plants into the ground everywhere they could find a scrap of plausible land: roadside ditches, backyard plots, the walls of the gullies below the houses. Somebody had stuck maize seedlings into a pickup-sized heap of dirt and gravel left by a recent landslide. During the eighteenth century, the same kind of thing took place all over China. Jamming maize and sweet potatoes into every nook and crevice, shack people and migrants almost tripled the nation’s cultivated area between 1700 and 1850. To create the necessary farmland, they knocked down centuries-old forests. Bereft of tree cover, the slopes no longer retained rainwater. Soil nutrients washed down the hills. Eventually the depleted land would not support even maize and sweet potatoes. Farmers would clear more forest, and the cycle would begin anew.* Some of the worst devastation was in the steep, crabbed hills of eastern central China, home of the shack people. Heavy, hammering rains, common in this area, constantly flush out minerals and organic matter. The weathered soil can’t hold water—“if it doesn’t rain for ten days,” one local writer said in 1607, “the soil becomes dry and scorched and cracks like the lines on a tortoise’s back.” The land was arable, in the sense that maize and sweet potatoes would grow in it.

But harvesting them for more than a season or two was next to impossible without shoveling in generous amounts of lime or ashes to reduce acidity, manure to boost organic matter, and fertilizer to increase nitrogen and phosphorus. This had to be done every year, because rain kept leaching nutrients.

Maize is planted in widely spaced rows, unlike wheat and millet, which is grown across solid blocks. Many farmers did not realize for a long time that maize therefore left more of the soil uncovered and hence exposed to rain. And some didn’t understand that planting the maize in rows straight up and down the hills, rather than across the slope, would channel that rain down the slope, increasing erosion.

Farmers used upstream dikes to hold back water until needed, controlling irrigation levels by adjusting gates. In a flood, the sudden gush of water could wipe out both the dikes and the paddies they fed, bringing down the whole system. Paradoxically, the deluges drowned the rice crop—and then, later, dried out the paddies because the dikes no longer held water for them. By cutting down the forests, the shack people were not only laying waste to the land around them, they were helping to devastate the agricultural infrastructure miles downstream. Because this was occurring in the lower Yangzi, the shack people were wrecking a chunk of the nation’s agricultural heartland.

Erosion from the heights drowned the rice paddies in the lower Yangzi valleys, further driving up the price of rice, which encouraged more maize production in the heights, which drowned more rice in the valleys.

The Qing (1644–1911) actively promoted moving peoples into mountain forests. As night follows day, the surge in migration led to a surge in deforestation; the flood rate more than tripled, to a little more than six major floods a year. Worse, the floods mostly targeted China’s agricultural centers.

Between 1841 and 1911, the Qing faced more than thirteen major floods a year—a Katrina every month, as one historian put it to me. “The government had constant disasters in the most populous parts of the realm,” he said. “The areas that were most important to feeding everyone.

Zhejiang censor Wang Yuanfang couldn’t understand it. In the past, he knew, landlords hadn’t understood that renting their unused upland property would have disastrous consequences. “Now [in 1850] the waterways are filled with mud, the fields are buried under sand, the mountains reveal their stones and the officials and people know of the great disaster, but they do nothing to stop it. Why?” (Emphasis in original.) In part, the failure was due to an inherent problem with mass illegal immigration. It is not easy to deport huge numbers of people—tearing them from homes and families built up over years—without mass suffering. Governments that seek popular support shrink from inflicting this kind of agony (unless the loss of support from one group is made up for by increased support from another). Logistically, there is also the problem of finding a destination for people who have left their original homes decades before. In the case of the shack people, Osborne argued, neither governmental queasiness nor confusion was the chief obstacle. The main problem was that the erosion represented a classic collective-action problem. A legal loophole ensured that rental income, unlike farm income, was tax free. Landowners with rentable property in the highlands thus had an easy source of untaxable income. The ensuing deforestation might ravage their own fields in the valleys, but the risks would be spread across an entire region, whereas the landowners’ profits were theirs alone. Absorbing all of the gain and only a fraction of the pain, local business interests beat back every effort to rein in shack people.

In an environmentalists’ nightmare, the shortsighted pursuit of small-scale profit steered a course for long-range, large-scale disaster. Constant floods led to constant famine and constant unrest; repairing the damage sapped the resources of the state. American silver may have pushed the Ming over the edge; American crops certainly helped kick out the underpinnings of the tottering Qing dynasty.

A series of weak emperors allowed the bureaucracy to wallow in inanition and corruption. The empire lost two wars with Great Britain, forcing it to cede control of its borders. British forces freely disseminated the opium that the government had gone to war to exclude. And so on—catastrophe, like success, has many progenitors.

Unknown to the rampaging European armies, though, their path had been smoothed by the Columbian Exchange.

The Huang He river rises one to three inches a year. Over time, it has lifted itself as much as 40 feet over the surrounding land. When farmers harvesting wheat fields want to see the river, they look up. Moving high in the air, the river wants (so to speak) to overflow its banks, spilling into the North China Plain and creating a ruinous flood. Such disasters have been a threat for millennia—“two breaks every three years and a channel change every century,” the Chinese used to say of the Huang He. But in the 18^th and 19^th centuries, erosion drove the breaks and channel changes to be more lethal. In an attempt to subdue the floods, the Qing established a corps of engineers who maintained a five-hundred-mile line of dikes, a network of spillways, locks, and dams, and an array of as many as sixteen secondary channels into which the river could be divided—a hydraulic infrastructure easily as impressive as the Great Wall, and one that was more important to the life of the nation. Not only did the system control a staggeringly complex irrigation network, it connected the river to the Grand Canal, a 1,103-mile passage between Beijing and Hangzhou (a port south of modern Shanghai) that is the longest artificial waterway in the world. Qing emperors may have spent 10 percent or more of the imperial budget on the Huang He.

Nonetheless the system was constantly overwhelmed. As the Chinese weather bureau maps show, excess silt made the Huang He spill over its banks a dozen times between 1780 and 1850—about once every six years. All of the floods were huge. One deluge in 1887 was among the deadliest ever recorded; estimates of the dead range up to a million.

The cause of the flooding—deforestation in the Loess Plateau—was well understood. But Beijing did little about it, even though much of the land clearance had its roots in Qing policies, and the floods were blows to imperial legitimacy. The court’s failure to act was not foreordained. Neither was the myopia of the landlords who rented to the shack people. Nobody will ever know whether decisive action could have resolved the nation’s ecological problems, because it wasn’t tried. Instead the floods continued until the dynasty fell, an event the floods had helped to bring about.

Which made it all the more incredible when Mao Zedong ordered more land clearing in the Loess Plateau. Most of the region was already deforested, but the steepest slopes—land too steep to farm—were still covered by low, scrubby growth that held back erosion. Exactly this land was targeted in the 1960s and 1970s for conversion, Dazhai style, into terraces. The terrace walls, made of nothing but packed earth, constantly fell apart; in one Loess Plateau village that I visited after a rainfall, half the population seemed to be shoring up crumbling terraces by pounding the walls flat with shovels. Even when the terraces didn’t crumble, rains sluiced away the nutrients and organic matter in the soil.

Because erosion removed nutrients, harvests in the newly planted land dropped quickly. To maintain yields, farmers cleared and terraced new land, which washed away in turn—a

Things look different on the ground. Provincial, county, and village officials are rewarded if they plant the number of trees envisioned in the plan, not whether they have chosen tree species suited to local conditions (or listened to scientists who say that trees are not appropriate for grasslands to begin with). Farmers who reap no direct benefit from their work—they are installing trees that do not produce fruit, cannot be cut for firewood, and supposedly stop erosion miles from their homes—have little incentive to take care of the trees they are forced to plant. The entirely predictable result is visible on the back roads of Shaanxi: fields of dead trees, each in its fish-scale pit, lining the roads for miles.

Agriculture was not the only cause of deforestation. China consumed huge quantities of timber as fuel and building material. To get the wood, platoons of workers went to distant places, where they wiped out entire forests. Alas, so much lumber was lost, damaged, and stolen during shipping, reported Yang Chang, a historian in Hubei Province’s Huazhong Normal University, that less than 2 percent of it was actually used by its intended recipients.

Natural rubber is essential to society

A few weeks after Goodyear announced his intent to produce temperature-stable rubber he was thrown into debtor’s prison. In his cell he began work, mashing bits of rubber with a rolling pin. He was untroubled by any knowledge of chemistry but boundlessly determined. For years Goodyear wandered about the northeastern United States in a cloud of penury, trailed by his hungry wife and children, dodging bailiffs and pawning heirlooms. All the while he was mixing toxic chemicals, more or less randomly, in the hope that they would make rubber more stable. The Goodyears lived in an abandoned rubber factory in Staten Island. They lived in an abandoned rubber factory in Massachusetts. They lived in a shack in a Connecticut neighborhood called Sodom Hill (the name indicated its wholesomeness). They lived in a second abandoned rubber factory in Massachusetts. Sometimes the houses had no heat or food. Two of Goodyear’s children died.

He borrowed $50,000 more to display an even more lavish rubber room at the second world’s fair, the Exposition Universelle in Paris. Parisians lost their urban hauteur and gawped like rubes at Goodyear’s rubber vanity table, complete with rubber-framed mirror; arranged on the top was a battalion of rubber combs and rubber-handled brushes. In the center of the rubber floor was a hard rubber desk with a rubber inkwell and rubber pens. Rubber umbrellas stood at attention in a rubber umbrella-stand in the corner of two rubber walls, each decorated with paintings on rubber canvases. For weapons fans, there was a stand of knives in rubber sheaths, swords in rubber scabbards, and rifles with rubber stocks. Except for the unpleasant rubber smell, Goodyear’s exhibit was a triumph.

Try to imagine a modern building without insulation on its wiring. Or imagine dishwashers, washing machines, and clothes dryers without the belts that transmit the motion of their engines to the appliance itself. Equally important but less visible, every internal combustion engine contains many pipes and valves that channel, usually under pressure, water, oil, gasoline, and exhaust vapor. Unless the parts are manufactured perfectly, engine vibrations will cause liquids or gases to vent dangerously from the joints. Flexible rubber gaskets, washers, and O-rings almost invisibly fill the gaps. Without them, every home furnace would be at constant risk of leaking natural gas, heating oil, or coal exhaust—a

The advent of synthetic rubber during the First World War failed to drive the Asians out of business. Despite the brilliance of industrial chemists, there is still no synthetic able to match natural rubber’s resistance to fatigue and vibration. Natural rubber still claims more than 40% of the market, a figure that has been slowly rising. Only natural rubber can be steam-cleaned in a medical sterilizer, then thrust into a freezer—and still adhere flexibly to glass and steel. Big airplane and truck tires are almost entirely natural rubber.

Xishuangbanna Prefecture is China’s most tropical place. Although it comprises just 0.2 percent of the nation’s land, it contains 25 percent of its higher plant species, 36 percent of its birds, and 22 percent of its mammals, as well as significant numbers of amphibians and freshwater fish.

After China decided to grow rubber here, workers were awakened every day at 3:00 a.m. and sent to clear the forest. Sneering at botanists’ admonitions as counterrevolutionary, the government repeatedly planted rubber trees at altitudes where they were killed by storms and frost. Then it planted them again in the exact same place—socialism would master nature, it insisted. The frenzy laid waste to hillsides, exacerbated erosion, and destroyed streams. But it didn’t actually yield much rubber.

In the late 1970s the nation began its economic reforms. The educated young people fled back to their home cities, precipitating a labor shortage. Local Dai and Akha villagers were finally permitted to establish rubber farms. They were effective and efficient. Between 1976 and 2003 the area devoted to rubber expanded by a factor of ten, shrinking tropical montane forest in that time from 50.8 percent of the prefecture to 10.3 percent.

Almost every bit of Xishuangbanna that can support rubber trees has been cleared and planted (top), a change that is profoundly altering the environment—the region’s morning mists are vanishing, along with its water supply.

Surface runoff rises by a factor of three—which in turn jacks up soil erosion by a remarkable factor of forty-five. Worse, the new leaves’ most intense growth occurs in April, at the dry season’s hottest, driest point. To propel growth, the roots suck up water from three to six feet below the surface.

“A lot of smaller streams are drying up,” he said. “Villages have had to move because there’s no drinking water.” Now spread this impact across Laos and Thailand…

Even if Xishuangbanna farmers were to stop planting H. brasiliensis tomorrow, its area would keep rising—on their own, rubber trees are invading the remaining forest

As the area of rubber increases, it becomes an increasingly inviting target for pests. “That’s the lesson of biology,” Tang said. “Diseases always come in. Sooner or later, they find a way.

In April 2008 the governments of Cambodia, China, Laos, Myanmar, and Thailand opened a brand-new highway that for the first time links all of these nations and connects them to Malaysia and Singapore. Trucks will be able to zoom in three days from Singapore to Kunming, the capital of Yunnan Province. If and when M. ulei arrives from Brazil, this will provide transportation. “In ten or twenty years, Xishuangbanna’s trees could be wiped out,” Tang said. “So would everyone else’s trees, probably.

The industrial revolution, one recalls, depends on three raw materials: steel, fossil fuels, and rubber. Imagine transportation networks without tires, electric power plants without gaskets and seals, hospitals without sterile rubber hoses and gloves. Industrial civilization could face such disruption worldwide that organizations from the United Nations to the U.S. Department of Defense list Microcyclus ulei as a potential biological weapon. Synthetic rubber will be deployed to replace it, but only as an imperfect replacement. “I sure as hell wouldn’t want to be in a 747 about to land on synthetic tires,” the director of the U.S. National Defense Stockpile Center has said.

Many slaves escaped and formed independent communities

Resistance was a constant presence. It didn’t matter to slaves whether they were owned by Portuguese, Afro-Portuguese, or Africans; they escaped when they could. Runaways joined together to form armed bands in the forest. To guard against their attacks, landowners built wooden forts staffed by gun-toting slaves. Judging by the frequency of successful assaults, the guards were rarely diligent. In a revolt in 1595 as many as five thousand slaves destroyed thirty sugar mills. The destruction was as understandable as it was pointless; the mills were going silent anyway. In a violent stasis, guerrilla warfare between plantations and runaways continued for almost two hundred years. São Tomé’s plantations eventually did switch to other crops: cocoa (from Brazil) and coffee (from the other side of Africa). These became profitable enough to lure back several hundred Portuguese,

Slavery had long been abolished legally, but Portugal kept it going as a practical matter by instituting special taxes in its African colonies. People unable to pay the levies were shipped to São Tomé to work off their debts, de facto slaves locked at night into dilapidated barracks on the plantation. As other nations joined the chocolate industry and improved manufacturing methods, the island’s antique cocoa plantations became less and less viable. An independence movement sprang up in the 1950s, its primary goal to end the plantation system. When Portugal left in 1975, the country was one of the poorest on earth. The new government nationalized the plantations. It combined them into fifteen super-plantations, then ran them almost exactly as before.

The colonies were supposed to contribute to the glory of Spain, a task that could not be accomplished without acquiring a labor force. Spain, unlike England, did not have a well-developed system of indentured servitude. And unlike England it did not have mobs of unemployed to lure over the ocean. To profit from its colonies, the monarchs believed, Spain would have to rely on Indian labor. In 1503 the monarchs provided their answer to the dilemma: the encomienda system. Individual Spaniards became trustees of indigenous groups, promising to ensure their safety, freedom, and religious instruction. In fine protection-racket style, Indians paid for Spanish “security” with their labor. The encomienda can be thought of as an attempt to answer the objections to slavery raised by Adam Smith. By restricting the demands on Indians, the monarchs sought to reduce the incentive for revolt—a benefit to the Spaniards who employed them. It didn’t work.

When native workers didn’t feel like showing up—why would they, if they could avoid it?—they vanished into the countryside, where their whereabouts were concealed by relatives, friends, and sympathetic Indian leaders. For their part, the Taino came to view the system as little but a legal justification for slavery. Under the law, Indian Christians were entitled after baptism to be treated exactly like Spanish Christians, who could not be enslaved. But colonists argued the contrary; Indians were, in effect, less human than Europeans, and thus could be forced to work even after they converted.

Africans had been trickling into the Americas almost as long as Europeans. By 1501, seven years after La Isabela’s founding, so many Africans had come to Hispaniola that the alarmed Spanish king and queen instructed the island’s governor not to allow any more to land. The governor was fine with that. He wrote “They flee to the Indians, and they learn bad customs from them, and they cannot be captured.” But the colonists saw that Africans appeared immune to disease, didn’t have local social networks that would help them escape, and possessed useful skills—many African societies were well known for their ironworking and horsemanship. Slave ships bellied up to the docks of Santo Domingo in ever-greater numbers.

The slaves were not as easily controlled as the colonists had hoped. Exactly as Adam Smith would have predicted, they were dreadful employees. Faking sickness, working with deliberate lassitude, losing supplies, sabotaging equipment, pilfering valuables, maiming the animals that hauled the cane, purposefully ruining the finished sugar—all were part of the furniture of plantation slavery. “Weapons of the weak,” political scientist James Scott called them in a classic study of the same name. The slaves were not so weak when they escaped to the heights. Hidden by the forest from European eyes, they made it their business to wreck the industry that had enchained them. For more than a century, African irregulars ranged unhindered over most of Hispaniola, funding their activities by covertly exchanging gold panned from mountain rivers with Spanish merchants for clothing, liquor, and iron (ex-slave blacksmiths made arrow points and swords).

American history is often described in terms of Europeans entering a nearly empty wilderness. For centuries, though, most of the newcomers were African and the land was not empty, but filled with millions of indigenous people. Much of the great encounter between the two separate halves of the world thus was less a meeting of Europe and America than a meeting of Africans and Indians—a relationship forged both in the cage of slavery and in the uprisings against it. Largely conducted out of sight of Europeans, the complex interplay between red and black is a hidden history that researchers are only now beginning to unravel.

Even when schoolbooks do acknowledge the hemisphere’s majority populations, they are all too often portrayed solely as helpless victims of European expansion: Indians melting away before the colonists’ onslaught, Africans chained in plantations, working under the lash. In both roles, they have little volition of their own—no agency, as social scientists say.

More often than is commonly realized they won it. Slaves vanished from the ken of their masters by the tens or even hundreds of thousands in Brazil, Peru, and the Caribbean. Spain recognized autonomous maroon communities in Ecuador, Colombia, Panama, and Mexico and used them as buffers against its adversaries.

What is known is that thirty thousand or more Africans fled to the Serra da Barriga and the nearby hills in the 1620s and 1630s, taking advantage of the disorder caused when the Dutch attacked and occupied the Portuguese coastal sugar towns during that time. Free of European control, the escapees built up as many as twenty tightly knit settlements centered on the Serra da Barriga, a haven for African, native, and European runaways. At its height in the 1650s, according to the Boston University historian John K. Thornton, the maroon state of Palmares “ruled over a vast area in the coastal mountains of Brazil, constituting a rival power unlike any other group outside Europe.

It had close to as many inhabitants at the time as all of English North America. It was as if an African army had been scooped up and deposited in the Americas to control an area of more than ten thousand square miles.

One of the most persistent myths about the slave trade is also one of the most pernicious: that Africans’ role was wholly that of hapless pawns. Except for the trade’s last few decades—and arguably not even then—Africans themselves controlled the supply of African slaves, selling them to Europeans in the numbers they chose at prices they negotiated as equals.

Africans were not forced by Europeans to sell other Africans, so why did they do it? Few Europeans or Africans at this time viewed slavery as an institution that needed to be explained, still less as an evil to be decried. Slavery was part of the furniture of everyday life; in both Europe and Africa, depriving others of their liberty wasn’t morally problematic, though it was bad to enslave the wrong person.

In western and central Europe, the most important form of property was land, and the aristocracy consisted mainly of large landowners who could buy or sell property with little legal restriction. In western and central Africa, by contrast, land was effectively owned by the government—sometimes personally by the king, sometimes by a kinship or religious group, most often by the state itself, with the sovereign exercising authority in the manner of a chief executive officer. No matter which arrangement held true in a given polity, though, the land could not be readily sold or taxed. What could be sold and taxed was labor. Kings and emperors who wanted to enrich themselves thus didn’t think in terms of occupying land but of controlling people. Napoleon sent his army to seize Egypt. An African Napoleon would have sent his army to seize Egyptians. As was the case in much of Europe, Africans could be sentenced to slavery if they forfeited their membership in society by committing a crime. People could be enslaved, too, to repay a debt, whether incurred by themselves, their families, or their lineages. In times of drought or flood they pawned family members to other members of their extended families or clans. Sometimes they pawned themselves.

But the most common way to acquire slaves was by sending troops across the border—that is, by war. Seventeenth-century West Africa was even more politically fragmented than Europe. A map prepared by Thornton shows more than sixty different states of wildly varying size. When leaders in one state wanted to aggrandize their status, a border was always nearby; it was easy to send out raiders. Captives would be taken by the king or given for sale to middlemen, who would take them to customers in North Africa or Europe.

In the beginning of the transatlantic slave trade, when European ships first became a constant presence on African shores, the difference between the two systems, European and African, was more a matter of culture than economics. Europeans could buy and sell labor—that was the purpose, to cite one example, of indentured-service contracts. And Africans could effectively own land by controlling the labor from the people who used that land. In both cases the owners ended up profiting from the fruits of the land and labor, even if the route to those profits was different. In economic terms, Europeans could own one of the factors of production (land), whereas Africans could own another (labor). Both systems gave owners the right to claim part or all of the products of that labor. Still, they were far from identical. One big distinction is that labor can be taken from one place to another in a way that land cannot. Labor is portable—a key factor for the later development of the slave trade.

Because labor was the main form of property in West Africa, rich West Africans almost by definition owned a lot of slaves. Plantations were rare in that part of the world—coastal West Africa’s soil and climate typically won’t support them—so big groups of slaves rarely were found working in fields as was common in American sugar or tobacco plantations. Instead slaves were soldiers, servants, or construction workers, building roads and fences and barns. Often enough they did almost nothing; wealthy, powerful slave owners kept more slaves than they needed, in the way that wealthy, powerful landowners in Europe would pile up unused land. In addition, much slave labor consisted of occasional work performed as a tax or tribute.

When Europeans arrived, they easily tapped into the existing slave trade. African governments and merchants who were already shipping human beings could increase production to satisfy the foreigners’ demands. Sometimes political leaders would hike criminal penalties to obtain slaves. Scofflaws, tax cheats, political exiles, unwanted immigrants—all went in the hopper. Usually, though, armies were sent to raid other nations. Or soldiers could abduct an important person in a neighboring polity and demand a ransom of slaves. If demand increased still further, private traders might seize captives without approval, angering the state. If no other source was available, Africans bought slaves from Europeans. In the seventeenth century, the Yale historian Robert Harms has estimated, Europeans sold forty to eighty thousand slaves to Africans in what is now Ghana.

When the flintlock replaced the undependable matchlock at the end of the seventeenth century, Africans were as keen to acquire the new guns as the Indians in Georgia and Carolina. In April 1732, traders from the rapidly growing Asante empire appeared at the Dutch fort of Elmina, in Ghana. They had a convoy of captives which they demanded to exchange for guns.

Hovering in their vessels along the coast, Dutch, Portuguese, and English slavers thus had little knowledge about the origins of the unhappy men and women on their ships. The colonists who rushed to buy their cargo on the quays of Jamestown, Cartagena, and Salvador had even less. According to Thornton, “only a handful of American slave owners seem to have actually known … that many thousands of them were prisoners of war.

When captive soldiers organized escapes and rebellions, some owners learned the import of their military backgrounds. From the beginning, American slave owners were dogged by the problem that their army of slaves could be an enslaved army.

Africans outnumbered Europeans seven to one by 1565. Unsurprisingly, Europeans found it hard to control their human property. Runaways grouped hundreds strong into multiethnic villages that were joined by escaped Indian slaves from the Andes and Venezuela and the remnants of free Indian groups from the isthmus. United by their loathing of Spaniards, they liberated slaves, slew colonists, and stole mules and cattle. Sometimes they abducted women. Losses mounted. Spain had a dreadful maroon problem.

From the colonists’ point of view, it was bad enough when nude, grease-smeared ex-slaves and Indians swept into Panamá town with their “very big and strong bows” and iron-tipped arrows, as one colonial official wrote in 1575, stealing cattle, carrying off slaves, and “usually killing the [Europeans] they meet.” Worse, the maroons, out of spite, threw whole shipments of silver and gold into the river. But then the maroons joined forces with the man who would become Spain’s most hated enemy: Francis Drake, the English pirate/privateer.

Decades later, Philip Nichols, who had served as Drake’s chaplain and become a friend, compiled surviving sailors’ reminiscences of the expedition, passed the manuscript by Drake for editorial approval, and published the result—the authorized biography I have been quoting—under the curious title of Sir Francis Drake Revived. The book portrays Drake’s sojourn in the isthmus—a time when he failed three times to seize large quantities of silver and lost half his men to disease and battle, including two of his brothers—as a rousing success.

The pirates and maroons split into two groups, one led by Drake, the other by Mandinga, about fifty yards apart from each other on the road. Drake’s group would let the mule train pass until it could be ambushed by Mandinga’s group. Then Drake and his men would close in from the rear, trapping the convoy fore and aft. Late in the evening the attackers heard the bells on the harnesses of the approaching mules. As soon as they came into view, an English sailor in Drake’s group charged drunkenly out of hiding, waving his weapon. One of the maroons yanked him back into the grass, but the damage was done—a Spanish advance scout had spotted the sailor’s white shirt in the moonlight. The scout wheeled about his horse, galloped back to the mule train, and told the treasurer to turn back to Panamá.

Testu had been jailed for four years in France because of his Protestant faith. Freed after protests to the king, he had accepted a privateering commission, probably from Italian merchants. Now he hoped to join with Drake in swiping Spanish treasure.

Again maroons led Europeans in a silent march through the forest, arriving at the ambush site on April 1. Again they split into two groups fifty yards apart along the road. In midmorning the waiting pirates and maroons heard bells—120 mules, the biography said, “every [one] of which caryed 300. Pound weight of silver, which in all amounted to neere thirty Tun.” This time the scheme succeeded. The guards fled, leaving the convoy in the hands of the pirates. Giddy but too weary to lug all the silver through the hills, the Anglo-Franco-Afro-Indian force stripped the mules of their glittering burden and in true pirate fashion buried the booty at the bottom of a nearby stream. They carried away a few silver bars as trophies. Not until they were miles from the ambush did they realize that a Frenchman was missing. Later they learned that he had gotten drunk while burying silver and missed their departure. He was caught by Spanish troops and revealed, under torture, the location of the silver.

All the while, English, French, and Dutch pirates were coming to the isthmus, asking the maroons to help them as they had helped Drake. Most didn’t get any assistance—the maroons seem to have acquired a low opinion of European competence

Maroons were fewer in the United States than farther south, because slaves could escape bondage altogether if they traveled north of the Mason-Dixon line. In addition, they found it harder to survive on their own in unfamiliar temperate ecosystems.

Nonetheless, maroon encampments were common in places like the valley of the Savannah River, the Mississippi River delta, and, especially, the Great Dismal Swamp, a peat bog that then sprawled across more than two thousand square miles of Virginia and North Carolina. (It is now smaller, because much of the swamp was drained in the nineteenth century.)

To escape European incursions, Indians moved there in numbers after about 1630, living in scattered, small settlements of ten to fifty houses. Africans soon followed.

Farther south, the best hope for slaves who wished to rid themselves of their bonds was the Spanish colony of Florida.

Under Seminole law, most Africans in those towns had the legal status of slaves, but native bondage resembled European feudalism more than European slavery. Seminole slaves owed little work; instead they were supposed to provide native villages with tribute, usually in the form of crops. The burden, though of course unwelcome and resented, usually was not onerous. Many of the slaves were African soldiers, disciplined and organized as one would expect from prisoners of war in wartime. Determined to establish themselves, maroons opened up trade with the Spanish and as a group became more prosperous than their Indian owners. For the most part they lived adjacent to but carefully separate from the Seminole, unincorporated into the big kinship-linked clans that were a principal aspect of Indian social networks. Yet they willingly joined their owners in common fights, of which there were, alas, all too many.

The Seminole strategy was twofold: First, they destroyed the plantations that supplied U.S. troops, capturing their slaves to bolster the native army. Second, they waited for yellow fever and malaria to kill northern soldiers. If they got in a jam, they pretended to negotiate until the onset of the “sickly season” forced U.S. forces to withdraw.

Haiti A French possession with about eight thousand plantations rich with sugar, coffee, and yellow fever, eighteenth-century Haiti was a true extractive state: forty thousand fabulously rich European colonists atop half a million seething African slaves.

Wanting to deny sugar revenues to France, England seized Haiti’s main cities in 1793. Its troops proved welcome hosts to that malign participant in the Columbian Exchange, the yellow fever virus. According to J. R. McNeill, the Georgetown historian of mosquito-borne disease, the British army lost roughly 10 percent of its troops every month between June and November of 1794. Survivors of yellow fever were prostrated by malaria. The army hung on, helped by reinforcements, until the next summer, when the monthly death rate rose to as high as 22 percent. “The newly arrived died with astonishing quickness,” McNeill wrote, “seemingly disembarking from ships straight to their graves.” Again they were reinforced: 13,000 more troops arrived in February 1796. In weeks 6,000 were dead. The British abandoned Haiti in 1798.

Napoleon Bonaparte had staged a coup in France and determined to retain the immensely profitable sugar and coffee plantations of Haiti. A French force of perhaps 65,000 landed in February 1802. Toussaint had barely half as many men and so little equipment and weaponry that his army was, he said, “naked as earthworms.” He ordered his rebels to retreat to the hills and await the fever season. Toussaint was captured and imprisoned but his strategy prevailed. By September some 28,000 French were dead; another 4,400 were hospitalized. Two months later the French commander died. His army struggled on, but it was trying to conquer its own cemetery. The effort collapsed in November 1803, having lost 50,000 of its 65,000 troops. As McNeill noted, the same malaria and yellow fever that had done so much to promote African slavery here helped Africans to destroy it. Napoleon, his hopes for a Caribbean empire in ruins, sold the United States all of France’s North American territories: the Louisiana Purchase.

Much of the United States’ present territory is thus owed indirectly to maroons.

All of Europe and the United States put a punishing economic embargo on Haiti for decades. Deprived of the trade in sugar and coffee that had been its economic lifeblood, the nation’s economy collapsed, impoverishing what had been the wealthiest society in the Caribbean.

Suriname’s planters begged for help. More than a thousand soldiers came across the Atlantic in 1772, among them John Gabriel Stedman, born in the Netherlands to a father who had fled Scotland’s famines. Stedman kept a diary that is an encyclopedia of medico-military calamity. Soon after landing he “became so ill by a fever—that I was not expected more to recover.” None of the other soldiers helped him: “Sickness being so common in this Country, and every one having so much ado to mind themselves, that neglect takes place betwixt the nearest acquaintances.” Stedman was lucky enough to survive his seasoning and go upstream. The once carefully managed Indian landscape was now a nightmare of pests. Stedman’s diary fairly pulses with complaint about the “inconceivable numerous” mosquitoes—insects in such thick, buzzing clouds that they smothered candles and made it impossible to see or hear people a hundred feet away.

“Out of a number of near 1200 Able bodied men, now not one hundred did return to their Friends at home,” Stedman wrote sadly, “Amongst whom Perhaps not 20 were to be found in perfect health.” All the others, he said, were “sick; discharged, past all Remedy; Lost; killed; & murdered by the Climate, while no less than 10 or 12 were drowned & Snapped away by the Alligators.

Eventually the Dutch and the maroons reached a kind of accommodation. The Europeans kept shipping in Africans and growing cane, accepting that a certain number of slaves would escape each year.

Meanwhile, most of the Dutch colonists stayed as little as they could; in 1850, after two centuries of colonization, Suriname had perhaps eight thousand European residents, most of them agents for sugar planters who lived safely in the Netherlands. Not residing in the colony, the growers had little interest in creating the institutions that underlie a productive society.

Every scrap of profit went back to the home country; education, innovation, and investment in Suriname were almost entirely ignored. When Suriname became independent in 1975, it was one of the poorest countries in the world.

Naturally, the new nation sought development. Suriname has large deposits of bauxite, gold, diamond, and oil and more tropical forest per capita than any other nation. The cash-strapped government—both the military dictatorship that seized power in 1980 and its civilian successor, which began in 1992—awarded mining and timber rights to foreign companies. In the 1960s, the colonial government had let Alcoa, the big aluminum company, build a six-hundred-square-mile lake to feed a hydroelectric dam for aluminum refining. Now the independent government awarded China International Marine Containers, the world’s biggest container-manufacturing firm, the rights to log almost eight hundred square miles to make wooden shipping pallets. Other firms followed suit. By 2007 some 40 percent of the country’s surface area had been leased for logging.

Within a decade of arrival the colonists—malarial, famished, living in wretched huts they were too poor to repair—were begging the crown to relocate them. Ultimately, almost all of the surviving Europeans slipped away. The remainder soon died. Through no act of their own, the slaves found themselves at liberty. Vila Nova Mazagão had become a quilombo. They were free as long as they pretended they weren’t. The Portuguese administration wanted to be able to report to the king that his subjects were guarding Brazil’s northern flank. The slaves were willing to say they were doing it, if that meant they would be left alone. Everyone was happy: the maroons pretended they were Portuguese subjects in a Portuguese colony and the Portuguese pretended the maroons were guarding the frontier. As the decades went by, the descendants of the colony’s Africans spread out along the riverbanks, living much like their Indian neighbors. The river supplied fish and shrimp, the small-scale garden cultivation yielded manioc, the trees provided everything else. Two centuries of constant tending and harvesting structured the forest. Mixing together native and African techniques, maroons created landscapes lush enough to be mistaken for pristine wilderness.

Slaves continued to escape and to live in the forest. But they didn’t repeat the mistake of forming big, centralized communities like Palmares. Instead they created ten thousand or more small villages in a flexible, shifting network that spread across much of eastern Brazil and the lower Amazon. They mixed with extant native settlements, collected Indian slave escapees, threw open their doors to Portuguese misfits and criminals. Many Africans had lived in tropical environments before being shipped across the ocean. They were comfortable in hot, wet places where people farmed palms and kept trapfuls of shrimp in the stream. They were happy to learn when Indians showed them how to fish by scattering poison in a tributary or make protective “boots” by melting latex over their feet or squeeze the bitter compounds out of manioc with long, tubular baskets.

To inexpert eyes, the riverbank across from Maria do Rosario’s home looks like a typical tropical hodgepodge. But almost every plant in this image was sown and tended by Rosario and her family, creating an environment as ecologically rich as it is artificial. (chart credit cha1.3) Five hundred miles southwest, the quilombo struggle for freedom is revisited even more overtly at the rite of lambe-sujo (an insulting reference to the red African cloth used for turbans—the equivalent, perhaps, of “towelhead”).

But the end of slavery did not mean an end to discrimination, poverty, and anti-maroon violence. The nation’s maroon communities continued to conceal themselves, staying so far out of official sight that by the middle of last century most Brazilians believed that quilombos no longer existed. In the 1960s, the generals who then ruled Brazil looked on their maps and observed to their displeasure that about 60 percent of the country was blank (actually, it was filled with Indians, peasant farmers, and quilombos, but the government dismissed them).

To the generals’ way of thinking, filling the emptiness was a matter of national security. In a breathtakingly ambitious program, they linked the brand-new, ultramodernist capital, Brasília, the western frontier, and the ports of the Amazon by slashing a network of highways across the interior.

In the 1970s and 1980s hundreds of thousands of migrants from central and southern Brazil thronged up the highways, believing the generals’ promises that they could begin new lives in new agricultural settlements. Instead, they encountered bad roads, poor land, and lawless violence: Deadwood with malaria. Many smallholders abandoned their farms soon after clearing them—few conventional annual crops would grow in Amazonia’s aluminum-saturated soil. In the long run, the big ranches didn’t do much better, even though many received subsidies from the military government.

In the short run, they deemed all people found on their property to be squatters and removed them, often at gunpoint. In this way countless quilombos were expunged, their inhabitants scattered—

Hundreds of exotic creatures have made the Philippines their home since Legazpi arrived in the 1560s. Introduced fish like tilapia and Thai catfish have wiped out almost all the local species of fish in Filipino lakes. South American shrubs have driven out local palms and bushes in Filipino parks. Water hyacinth from Brazil chokes the rivers in Manila; weeds from Africa grow over rice paddies. Seven of the immigrants are on a hit list of the one hundred worst invasive species compiled by the International Union for the Conservation of Nature. A small minority of the newcomers were environmentally or economically damaging and only a very few harmed the ecosystem itself, impairing its ability to filter water or grow plant matter or process nutrients into the soil. But to the scientists in the room almost all the exotics were problematic, because they were helping, in ways large and small, to turn the Philippines from what it had been before Spain into something else—a homogenized, internationalized, airport-shopping-mall version of itself, a vest-pocket version of the Homogenocene. The island landscape, they said with some heat, was less and less what it had been before.

The effect of worms from Europe on America’s ecology

London tobacco houses were thrilled by the sudden appearance of an English alternative: Virginia leaf. They clamored for more. Ships from London tied up to the Jamestown dock and took in barrels of rolled-up tobacco leaves. Typically four feet tall and two and a half feet across at the end, each barrel held half a ton or more. To balance the weight, sailors dumped out ballast, mostly stones, gravel, and soil—that is, for Virginia tobacco they swapped English dirt.

That dirt very possibly contained the common nightcrawler and the red marsh worm. So, almost certainly, did the rootballs of plants the colonists imported. Until the nineteenth century, worms like these were viewed as agricultural pests. Charles Darwin was among the first to realize they were something more; his last book was a three-hundred-page celebration of earthworm power. Huge numbers of these beasts, he noted, live beneath our feet; indeed, the total mass of the earthworms in a cow pasture may be many times the mass of the animals grazing above them. Literally eating their way through the soil, earthworms create networks of tunnels that let in water and air. In temperate places like Virginia, earthworms can turn over the upper foot of soil every ten or twenty years; tiny

In worm-free woodlands, leaves pile up in drifts on the forest floor. When earthworms are introduced, they can do away with the leaf litter in a few months, packing the nutrients into the soil in the form of castings (worm excrement). As a result, according to Cindy Hale, a worm researcher at the University of Minnesota, “everything changes.” Trees and shrubs in wormless places depend on litter for food. If worms tuck nutrients into the soil, the plants can’t find them. Many species die off. The forest becomes more open and dry, losing its understory, including tree seedlings. Meanwhile, earthworms compete for food with small insects, driving down their numbers. Birds, lizards, and mammals that feed in the litter decline as well. Nobody knows what happens next. “Four centuries ago, we launched this gigantic, unplanned ecological experiment,” Hale told me. “We have no idea what the long-term consequences will be.

European farming and way of life sucked the life out of the soil

The colonists covered big areas with stands of N. tabacum. Neither natives nor newcomers understood the environmental impact of planting it on a massive scale. Tobacco is a sponge for nitrogen and potassium. Because the entire plant is removed from the soil, harvesting and exporting tobacco was like taking those nutrients from the earth and putting them on ships. “Tobacco has an almost unique ability to suck the life out of soil,” said Leanne DuBois, the agricultural extension agent in James City County, Jamestown’s county. “In this area, where the soils can be pretty fragile, it can ruin the land in a couple of years.” Constantly wearing out fields, the colonists had to keep moving to new land.

Subject to annual burning, native woodlands had been both open, in that people could freely move around, and closed, in that the canopy of big trees sheltered the land from the impact of rainfall. Taking down the forest exposed the soil. Colonists’ ploughs increased its vulnerability. Nutrients dissolved in spring rains and washed into the sea. The exposed soil dried out more quickly and hardened faster, losing its ability to absorb spring rains; the volume and speed of runoff increased, raising river volume. By the late seventeenth century disastrous floods were common. So much soil had washed into the rivers that they became difficult to navigate.

Scale insects arrive in the new world from Africa and decimate fruit orchards

When Spanish colonists imported African plantains in 1516, the Harvard entomologist Edward O. Wilson has proposed, they also imported scale insects, small creatures with tough, waxy coats that suck the juices from plant roots and stems. About a dozen banana-infesting scale insects are known in Africa. In Hispaniola, Wilson argued, these insects had no natural enemies. In consequence, their numbers must have exploded—a phenomenon known to science as “ecological release.” The spread of scale insects would have dismayed the island’s European banana farmers but delighted one of its native species: the tropical fire ant Solenopsis geminata. S. geminata is fond of dining on scale insects’ sugary excrement; to ensure the flow, the ants will attack anything that disturbs them. A big increase in scale insects would have led to a big increase in fire ants. In 1518 and 1519, according to Bartolomé de Las Casas, a missionary priest who lived through the incident, Spanish orange, pomegranate, and cassia plantations were destroyed “from the root up.” Thousands of acres of orchards were “all scorched and dried out, as though flames had fallen from the sky and burned them.” The actual culprit, Wilson argued, was the sap-sucking scale insects. But what the Spaniards saw was S. geminata—“an infinite number of ants,” their stings causing “greater pains than wasps that bite and hurt men.” The hordes of ants swarmed through houses, blackening roofs “as if they had been sprayed with charcoal dust,” covering floors in such numbers that colonists could sleep only by placing the legs of their beds in bowls of water. They “could not be stopped in any way nor by any human means.

Chinese population explosion, destruction of forests, erosion, and floods

With silver Spain finally had something China badly wanted when it became China’s money supply. But there was an unease about having the nation’s currency in the hands of foreigners. The court feared that the galleon trade—the first large-scale, uncontrolled international exchange in Chinese history—would usher in large-scale, uncontrolled change to Chinese life. The fears were entirely borne out. Although emperor after emperor refused entry to almost all human beings from Europe and the Americas, they could not keep out other species. Key players were American crops, especially sweet potatoes and maize; their unexpected arrival, the agricultural historian Song Junling wrote in 2007, was “one of the most revolutionary events” in imperial China’s history. The nation’s agriculture, based on rice, had long been concentrated in river valleys, especially those of the Yangzi and Huang He (Yellow) rivers. Sweet potatoes and maize could be grown in the dry uplands. Farmers moved in numbers to these areas, which had previously been lightly settled. The result was a wave of deforestation, followed by waves of erosion and floods, which caused many deaths. The regime, already straining under many problems, was further destabilized—to Europe’s benefit.

Too much debt led to starvation and uprisings in Europe

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.

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.)

Miscellaneous

Scholars had known for more than 1500 years that the world was large and round. Colón disputed both facts. The admiral’s disagreement with the second fact was minor. The earth, he argued, was not perfectly round but “in the shape of a pear, which would all be very round, except for where the stem is, where it is higher, or as if someone had a very round ball, and in one part of it a woman’s nipple would be put there.” At the very tip of the nipple, so to speak, was “the Earthly Paradise, where nobody can go, except by divine will.” (During a later voyage he thought he had found the nipple, in what is now Venezuela.)
The Virginia Company came into existence because English sovereigns—Queen Elizabeth I and her successor, James I—wanted the benefits of trade and conquest but couldn’t pay for them. The state had been pushed so deeply into debt by war (in Elizabeth’s case) and profligacy (in James’s case) that it could not afford to send ships to the Americas. Nor could it borrow the necessary cash. From moneylenders’ point of view, the monarchy was a bad credit risk—it could, and all too often did, assert its prerogative to repudiate its debts. In consequence, they charged it ruinously high interest rates. True, kings and queens had the power to force loans from their subjects, a practice that for obvious reasons was deeply unpopular. But was the certainty of incurring discontent worth the gamble of an American colony? Elizabeth and James came to the same conclusion: no.
Settlers sent a ransom note to Powhatan: to get back his daughter, he would have to return all the swords, guns, and metal tools “he treacherously had stolen,” along with all the English prisoners of war. For three months Powhatan refused to negotiate with people he regarded as criminals. Finally he sent back a handful of English captives with an offer: 500 bushels of maize for the girl. The guns and swords could not be returned, he said, because they had been lost or stolen. Dale scoffed at this claim. Communications ceased for another eight months, during which time some of the freed English captives ran back to the Indians—they preferred Tsenacomoco with its foreign culture and language
Nicotine addiction became so rampant so quickly in Manchuria, according to the Oxford historian Timothy Brook, that in 1635 the khan Hongtaiji discovered that his soldiers “were selling their weapons to buy tobacco.” The khan angrily prohibited smoking.