Manila’s traders, having no alternative, begged Zheng in 1657 to buy their silver. When his ships appeared in the harbor, the galleon trade resumed. Perhaps distracted by his running battle with the Qing, Zheng took longer than one would expect to realize that a) the Spaniards in the Philippines had no source but him for silk and porcelain; and b) he, Zheng, was a pirate with a large army. Not until 1662 did he dispatch the Dominican missionary—dressed in the rich robes of an imperial emissary—to Manila with a proposal to change the terms of trade. The Spaniards would give him all their silver, as before. In return, Zheng would not kill them. Panicked, the Spanish governor decided to expel the Chinese in the Philippines. Refusing to be ejected, they barricaded themselves in the Parián. As was by that point customary, Spanish troops forcibly rounded up the Chinese, slaughtering many and forcing the rest to leave Manila on jam-packed ships. The precaution turned out to be needless; just two months later, Zheng died unexpectedly, probably of malaria. His sons fought over their inheritance, and the Manila trade was left alone.
The Qing had ordered the coastal evacuation, but it had disastrous consequences for them, too. As the treasury official Mu Tianyan complained, closing down the silver trade effectively froze the money supply. Because silver was always being wasted, lost, and buried, the pool of Chinese money was actually shrinking. “Every day there is less and less to meet the demand, with no way to restore it,” Mu wrote to the emperor. When the money supply falls, each unit becomes more valuable; prices fall in a classic deflationary spiral. To stop the importation of silver “yet desire the wealth of fortune and convenience of use,” Mu asked, “how is this different from blocking a source of water while expecting to benefit from its flow?” Reluctantly agreeing, the Qing lifted the ban in 1681.
Meanwhile, though, coastal people had flooded into the mountains of Fujian, Guangdong, and Zhejiang. Inconveniently, these areas were already inhabited. Most of the inhabitants belonged to a different ethnic group, the Hakka, famed for their tulou—fortress-like complexes, usually but not always circular, whose earthen outer walls contain scores of apartments, all facing onto a central courtyard. (Today these amazing structures are a tourist attraction.) Decades before the expulsion, the Fujianese scholar Xie Zhaozhe had observed that the Hakka in the hills were packed into every scrap of available real estate:
There is not an inch of open ground.… Truly as someone once said, “Not a drop of water goes unused, and as much as possible even the most rugged parts of mountains are cultivated.” One could say that there isn’t a bit of land left.
Unable to support themselves, poor Hakka and other mountain peoples had been emigrating north and west for a century, renting uninhabited highland areas—terrain too steep and dry for rice—in neighboring provinces. They cut and burned the tree cover and planted cash crops, mainly indigo, in the exposed earth. After a few years of this slash-and-burn the thin mountain soil was exhausted and the Hakka moved on. (“When they finish with one mountain, they simply move on to the next,” the geographer Gu Yanwu complained.) As coastal refugees poured into the mountains, the highland exodus accelerated.
Landless and poor, the Hakka refugees were mocked as pengmin—shack people. Strictly speaking, shack people were not vagabonds; they rented land in the heights that was owned but not used by farmers in the more fertile valleys. Shifting from one temporary home to the next, pengmin eventually occupied a crooked, 1,500-mile stretch of montane China from the sawtooth hills of Fujian in the southeast to the silt cliffs around the Huang He in the northwest.
Neither rice nor wheat, China’s two most important staples, would grow in the shack people’s marginal land. The soil was too thin for wheat; on steep slopes, the irrigation for rice paddies requires building terraces, the sort of costly, hugely laborious capital improvement project unlikely to be undertaken by renters.
Thousands of toulou, clan dwellings of the Hakka, still dot the mountains of Fujian. Made from rammed earth mixed with rice stalks, they had no windows on lower floors as a defensive measure. (Photo credit 5.3)
Almost inevitably, they turned to American crops: maize, sweet potato, and tobacco. Maize (Zea mays) can thrive in amazingly bad land and grows quickly, maturing in less time than barley, wheat, and millet. Brought in from the Portuguese at Macao, it was known as “tribute wheat,” “wrapped grain,” and “jade rice.” Sweet potatoes will grow where even maize cannot, tolerating strongly acid soils with little organic matter and few nutrients. I. batatas doesn’t even need much light, as one agricultural reformer noted in 1628. “Even in low, narrow, damp alleys, where there is only a few feet of ground, if you can look up and see the sky, you can plant them there.”
In the south, many farmers’ diets revolved around the sweet potato: sweet potatoes baked and boiled, sweet potatoes ground into flour for noodles, sweet potatoes mashed with pickles or deep-fried with honey or chopped into stew with turnips and soybean milk, even sweet potatoes fermented into a kind of wine. In the west, China was a land of maize and another American import: potatoes, originally bred in the Andes Mountains. When the wandering French missionary Armand David lived in a hut in remote, scraggy Shaanxi, his meal plan would not have been out of place, except for a few garnishes, in the Inka empire. “The only plant cultivated near our cabin is the potato,” he noted in 1872. “Maize flour, along with potatoes, is the mountain peoples’ daily diet; it’s usually eaten boiled and mixed with the tubers.”
Nobody knew how many shack people were in the hills. Hoping, perhaps, that hiding the problem would avoid the need to solve it, Qing bureaucrats left them out of census reports. But all evidence suggests that the number was not small. In Jiangxi, Fujian’s western neighbor, the rigid, nit-picking provincial treasurer insisted in 1773 that the shack people, many of whom had lived in Jiangxi for decades, counted as actual inhabitants of the province and therefore should be included in the reports sent to Beijing. He dispatched field workers to enumerate every Hakka head and every Hakka shack. In rugged Ganxian County, they tallied 58,340 settled inhabitants, most in the main town of Ganzhou—and 274,280 shack people in the surrounding slopes. In county after county the story was repeated, sometimes with a few thousand wanderers, other times a hundred thousand or more. Hidden from the government, more than a million shack people had been slashing and burning their way across Jiangxi. And that, as the Qing court must have realized, was only one medium-sized province.
Coupled with the outflow of shack people was a second, parallel, even bigger wave of migration into the parched, mountainous, thinly settled west. In their quest for social stability, the Ming had prohibited people from leaving their home regions. Reversing course, the Qing actively promoted a westward movement. Much as the United States encouraged its citizens to move west in the nineteenth century and Brazil provided incentives to occupy the Amazon in the twentieth, China’s new Qing masters believed that filling up empty spaces was essential to the national destiny. (“Empty,” that is, from the Qing point of view; dozens of non-Chinese peoples—Tibetans, Yao, Uighurs, Miao—lived in them. By sending in people from the center, the Qing were forcibly incorporating these previously autonomous cultures into the nation.)3 Lured by tax subsidies and cheap land, migrants from the east swarmed into the western hills. Most of the newcomers were, like the shack people, poor, politically luckless, and scorned by urban elites. They looked at the weathered, craggy landscape, so unwelcoming to rice—and they, too, planted American crops.
China’s fifth-largest province is Sichuan, adjacent to Tibet and nearly as alpine. Back in 1795, according to Lan Yong, a historian at Sichuan’s Southwest University, it was a big, roomy place: more land than California, a population as low as 9 million. Just 2,300 square miles of its surface, an area half the size of Los Angeles County, were considered arable. During the next twenty years, Lan has written, American crops moved into the ridges and highlands, increasing the pool of farmland to almost 3,700 square miles. As Sichuan’s agricultural capacity increased, its populati
on increased in tandem, to 25 million. Something similar occurred in Shaanxi Province, Sichuan’s even emptier neighbor to the northeast. Migrants poured into the steep, arid hills along the border between them, knocking down the trees that clung to the slopes to make room for sweet potatoes, maize, and, later, potatoes. The amount of cropland soared, followed by the amount of food grown on that cropland, and then the population. In some places the number of inhabitants increased a hundredfold in little more than a century.
For almost two thousand 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.
China was not the only Asian nation transformed by the Columbian Exchange. Sweet potatoes became a staple in a broad swath extending from Tahiti to Papua New Guinea, and from New Zealand to Hawai’i. Surprisingly, I. batatas was known in much of this area before Columbus—archaeologists have found burned remains of the plant dating back as early as 1000 A.D. in Hawai’i, Easter Island, the Cook Islands, and New Zealand. (Some researchers view the species’s movement across the Pacific as evidence of contact between ancient Polynesians and American Indians; others argue that the seeds, which are contained in small, buoyant, spherical capsules, must have floated across the sea.) Initially it had little impact. But about the time that the Spaniards arrived in Manila I. batatas was 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.
Maize at the edge of the Gobi Desert, in Inner Mongolia (Photo credit 5.4)
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. Some of these policies had been first emplaced by the Ming; the Qing merely executed them efficiently. But all helped raise the number of children, and the proportion of that number who survived to adulthood.
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.
MALTHUSIAN INTERLUDE
Hong Liangji was born in 1746 near the mouth of the Yangzi, into a family that slowly went on the skids after the unexpected death of his father. Brilliant but volatile, tall and red-faced, Hong “was in his element when he was singing and drinking,” one friend recalled. He was often upbraided at school for drunken antics even as he won prizes for his intellect and prose style. An intense, impatient, and easily infuriated man, he would grab his interlocutor’s wrist, lean in close, and hammer his point home with febrile intensity. “His eyes would narrow and you could see his neck redden with anger,” another friend said, remembering political discussions. “Then he was extremely unsociable.” His friends put up with him because he was a fine poet, a lively essayist, and a noted scholar who studied waterways, reconstructed administrative boundaries, and assembled a comprehensive geography of the Qing empire. His greatest intellectual feat, though, passed almost unnoticed. Sometime in 1793 Hong Liangji thought of an idea that may never have occurred to anyone else before.
After finally winning a place in the Qing bureaucracy at the age of forty-four—Hong had failed the civil service exam four times—he was sent as an education inspector to Guizhou Province, in the southwestern hinterland. Essentially a sloping, heavily eroded limestone shelf, the province is a humid jumble of steep gorges, protuberant hills, and long caverns. It was another target for Qing occupation, thronged with migrants from central China who were pushing out its original inhabitants, the Miao. The newcomers were climbing up the hills, planting maize, and beginning families. Hong wondered how long the boom could last.
“Today’s population is five times as large as that of thirty years ago,” he wrote, with perhaps pardonable exaggeration, “ten times as large as that of sixty years ago, and not less than twenty times as large as that of a hundred years ago.” He imagined a man with “a ten-room house and 100 mu [about seventeen acres] of farmland.” If the man married and had three adult sons, then eight people—the four men and their wives—would live on the parents’ farm.
Eight people would require the help of hired servants; there would be, say, ten people in the household. With the ten-room house and the 100 mu of farmland, I believe they would have just enough space to live in and food to eat, although barely enough. In time, however, there will be grandsons, who, in turn, will marry. The aged members of the household will pass away, but there could still be more than twenty people in the family. With more than twenty people sharing a house and working 100 mu of farmland, I am sure that even if they eat very frugally and live in crowded quarters, their needs will not be met.
Hong conceded that the Qing had opened up new land to support China’s population. But the amount of farmland had
only doubled or, at the most, increased three to five times, while the population has grown ten to twenty times. Thus farmland and houses are always in short supply, while there is always a surplus of households and population.…
Question: Do Heaven-and-earth have a way of dealing with this situation? Answer: Heaven-and-earth’s way of making adjustments lies in flood, drought, and plagues.
Five years later, in England, a similar notion came to another man: Rev. Thomas Robert Malthus. A shy, kindly fellow with a slight harelip, Malthus was the first person to hold a university position in economics—that is, the first professional economist—in Britain, and probably the world. He was impelled to think about population growth after a disagreement with his father, a well-heeled eccentric in the English style. The argument was over whether the human race could transform the world into paradise. Malthus thought not, and said so at length—55,000 words, published as an unsigned broadside in 1798. Several longer versions followed. These were signed; Malthus had become more confident.
“The power of population,” Malthus proclaimed, “is indefinitely greater than the power in the earth to produce subsistence for man.” In textbooks today this notion is often depicted by recourse to a graph. One line on the graph represents the total food supply; it slowly rises in a line from
left to right as people clear more land and farm more efficiently. Another line starts out low, quickly curves to meet the first, then soars above it; that line represents human population, growing exponentially. Eventually the gap between the two lines cannot be bridged, and the Four Horsemen of the Apocalypse pay a call. Every effort to increase the food supply, Malthus argued, will only lead to an increase in population that will more than cancel out the increase in the food supply—a state of affairs today known as a Malthusian trap. Forget Utopia, Malthus said. Humanity is doomed to exist, now and forever, at the edge of starvation. Forget charity, too: helping the poor only leads to more babies, which in turn produces increased hardship down the road. No matter how big the banquet grows, there will always be too many hungry people wanting a seat at the table. The Malthusian trap cannot be escaped.
The reaction was explosive. “Right from the publication of the Essay on Population to this day,” the great economic historian Joseph Schumpeter declared, “Malthus had the good fortune—for this is good fortune—to be the subject of equally unreasonable, contradictory appraisals.” John Maynard Keynes regarded Malthus as the “ beginning of systematic economic thinking.” Percy Bysshe Shelley, on the other hand, derided him as “a eunuch and a tyrant.” John Stuart Mill viewed Malthus as a great thinker. To Karl Marx he was a “plagiarist” and a “shameless sycophant of the ruling classes.” “He was a benefactor of humanity,” Schumpeter wrote. “He was a fiend. He was a profound thinker. He was a dunce.”