Early large-scale human migration is the story of dispersal, spreading out as resources were used up and populations expanded past sustainability. The Agricultural Revolution brought greater inter-community trade and migration, including significant migration from rural areas to cities. Empires created the most widespread intercultural migration yet, but it wasn’t until the Age of Exploration that migration and trade increased dramatically. Falling travel costs brought millions of (mostly free) migrants to the New World and other European colonies for employment. Economic liberalism reinforced this trend toward globalization, but world war, nationalism, and more effective bureaucratic states ended this free system.
Humanity’s great migration began in Africa around 80,000 years ago when the human population seems to have dwindled to a few thousand. Richard Klein—author of The Human Career—has argued that genetic mutations in this small population gave rise to abstract thought and perhaps other capacities that led to rapid growth thereafter. In any case, the human population quickly expanded beyond the savannahs of eastern and southern Africa to the northern savannah between Ethiopia and Senegal.
Around 60,000 years ago, humans crossed the strait of Bab el Mandeb into Arabia, and they “quickly” dispersed along the coasts, and by 40,000 years ago, humans lived along the coasts from West Africa to Australia (the first movement out of the tropics). After Australia, people moved into colder climates in Eurasia and China. By 20,000 years ago, people had entered North America, and by 10,000 years ago, migrants lived on every continent in the world, except Antarctica. Although long-distance, cross-culture trade began as far back as 40,000 years ago—based on seashell jewelry found far inland and stone tools constructed from nonlocal materials—most inter-community migration was local, the most important being migrant brides who transferred customs between tribes.
The Agricultural Revolution saw these divergent communities begin to reconnect. The Revolution was brought on by the end of an ice age and a warmer, but more volatile climate. Sedentary communities began to appear and gradually adopt agriculture. Urbanization created epidemics that wiped out huge portions of the Sumerian working population, only to be replaced by Akkadians from rural areas. So great was this rural to city migration that Akkadian became the official language of the empire. As trade between communities increased, immigration also increased. Clay tablets, for example, record that Assyrian traders had established commercial communities in modern Turkey by 2000 BCE. At the same time, large-scale trade networks emerged from Mesopotamia to Asia Minor.
Migrants carried cultural innovations like the Phoenician alphabet, which spread throughout the region and influenced the Greek, Amarmaic and Brahmi alphabets. Ideas, however, were still transmitted very slowly throughout the early period of human migration, as they required being passed through several intermediaries to reach from one civilization to another. The rise of empires sped the rate of information transfer. When China’s Tang Dynasty and the Abbasid Caliphate, for example, met in battle, the contact brought papermaking all the way to the Mediterranean. The Abbassid Caliphate also helped to foster large trade diasporas, most importantly the Jewish Radanites who connected traders from Europe to China. The Tang Empire was so powerful it received ambassadors from as far as Arabia and Antioch, which hastened cultural exchange.
By 1000 CE, Mediterranean trade began to increase. While Italian traders dominated the Mediterranean, English King Edward I issued the Carta Mercatoria in 1303, which guaranteed freedom to trade and exemptions from tolls, and in 1334, Edward III extended a special commercial charter to the Hanseatic League. Trade also brought new innovations together. Large ships like Venetian galleys, Indian dhows, and Chinese junks began to replace overland trade, and the Chinese magnetic compass allowed ever-longer trips. Similar commercial practices like the use of banking checks began to spread during this period, which set the stage for true globalization in the coming centuries.
The Chinese Admiral Zheng He—a Mongol immigrant himself—was the first to launch the age of exploration under the Ming Dynasty with ships carrying 20,000 men. As many as 30 emissaries from foreign states returned with him to China, but after the Emperor died, China attempted to cut itself off from the outside world. From this point, European explorers led by Columbus and Vasco da Gama—whose 1497 voyage to India created the first permanent direct link between Europe and India—helped to build the first global economy.
In the early 16th Century, Francesco de Vitoria—a Roman Catholic philosopher—helped pioneer international law. He argued that migration was a natural right, writing that “it was permissible from the beginning of the world when everything was in common for anyone to set forth and travel wheresoever he would.” Hugo Grotius, Samuel von Pufendorf, Christian Wolff and others argued that states had as much a duty to protect the rights of migrants as they did their own citizens.
Monopolistic trading companies during this period became essentially “armed politico-commercial organizations,” as Jonathan Israel put it, and employed huge mercenary armies. At least half of the Dutch East Indian company’s soldiers were actually from poor areas in Germany. These violent interventions into Asia, Africa, and the New World eventually led to colonies, which escalated labor migration to unprecedented levels. Slavery dragged 15.7 million people from Africa including 10.3 million to the Americas (most before 1808). 2.6 million Europeans moved to the New World before 1820, a quarter under indentured labor contracts.
Slavery’s abolition and the assent of economic liberalism led to a period of relatively liberal migration. Meanwhile, fast and inexpensive ocean travel increased worldwide trade tenfold and also made it profitable to recruit labor at great distances. Indentured labor became increasingly popular, and as many as 37 million migrants worked such contracts between 1834 and 1941, incentivized by higher colonial wages. In 1870, for example, wages were 5 times higher in the West Indies and 9 times higher in Hawaii than an India. Most migrant laborers declined to become permanent residents. Almost 80 percent of indentured Indians returned to India, but large populations remain in Uganda, Kenya, Malasia, Guyana and elsewhere.
Worldwide economic growth brought huge waves of migrants to the Americas. Between 1850 and the mid-1870s, North America saw the number of European migrants double from 300,000 per year to 600,000. By 1900, it went to over a million. Migration from all countries peaked at over 3 million per year to the New World. While Chinese migrants built the transcontinental railroad in the Western United States, Indians were building East African lines (as the Irish did in South Africa). The 1868 Meiji Restoration opened Japan, and thousands of Japanese emigrated to Brazil and ultimately to the U.S. and Canada to replace the excluded Chinese.
Industrialization in Europe created dislocations that sent migrants to cities in search of employment, which connected them to international trade and migratory networks for the first time. Meanwhile, fares from the Europe dropped 70 percent, which made migration less risky. In the century prior to 1920, 60 million Europeans came to the Americas, but nearly half of these returned (more like a third from the U.S.). It wasn’t just the United States that saw huge numbers of migrants. Between 1890 and 1910, Argentina actually saw higher rates of migration than the U.S. and Canada at around 20 percent of its population (compared to 5-10 percent). Brazil also aggressively recruited migrant workers who ended up becoming entrepreneurs. By 1934, immigrants owned 44 percent of Sao Paulo’s factories and shops.
Southeast Asia saw 50 million Indians and Chinese move throughout the region. North Asia’s population grew from 22 million in 1850 to over 104 million in 1950 as Koreans, Japanese and Russians all rushed to find employment at mines there. Seasonal migration also became much more common as travel costs fell. The late nineteenth century saw the first “guest worker program” in Germany, which previewed the era of managed migration that came about as a result of World War I, the rise of nationalism, more competent state bureaucracies, public welfare, and the decline of economic liberalism.