World migration patterns

DEFINITION: Trends and patterns in international human migration in modern world history

SIGNIFICANCE: Although the United States has had a unique immigration history, many elements of immigration into the country fit into broad patterns affecting other parts of the world, particularly Western Europe. US immigration history cannot, therefore, be fully understood without reference to its place in a global context.

In his 1995 study of global migration, Myron Weiner identified five distinct eras of immigration that had occurred since the Renaissance. The United States featured centrally in each, although perhaps less so than Europe. The first two eras stretched from the seventeenth century through World War I (1914–18). Those eras encompassed Europe’s acquisition of colonies in the Americas, Australia, and New Zealand during the seventeenth, eighteenth, and very early nineteenth centuries, and the settlement of those colonies through the nineteenth century. North America in general and the United States in particular benefited from the arrival of immigrants from Great Britain, France, Ireland, Germany, Italy, and their neighboring donor states in southern and eastern Europe.

The same eras also saw European governments shape the travel of non-Europeans to distant regions, most aggressively through the slave trade. During Weiner’s three subsequent eras of twentieth-century global migration, the United States continued to become an ever more ethnically diverse country of immigrants, and Europe itself was profoundly reshaped by immigrant flows. These eras continue to be studied to reveal how human migration has evolved over time and in response to factors such as war, political unrest, and agricultural and industrial development; such an analytical framework also provides insight into contemporary and future trends in world migration.

The Age of Colonialism

History, and the spread of humanity across the globe, is to no small extent the story of ancient migrations. However, Weiner and most modern historians and sociologists date the modern waves of migration from those of the sixteenth to eighteenth centuries, when European governments in their search for wealth and power sent their peoples to remote lands, first to find goods of value and then to secure their holdings with settlements or colonies, a process that became known as colonialism. Most of these early settlements were merely coastal affairs, under the protective cannon of their homeland’s warships. European firearms were primitive by the standards that would develop during the nineteenth century, but even the single-shot, muzzle-loading weapons that earlier empire builders brought with them from Europe were superior to most weapons of the native peoples whom they encountered in the Americas, Australasia, Asia, and Africa, and the numbers in which they eventually arrived were overwhelming to Indigenous populations. However, neither their numbers nor their weaponry were great enough to enable them to move far from their initial settlements and the protective cover they enjoyed there.

The numbers of settlers involved during the long initial era of modern migration were not insignificant by the European standards of the time. Before 1820, an estimated 240,000 Europeans migrated to North America alone. Some came as indentured servants, and many sought to escape the religious and political persecution they experienced in Europe. To these must be added the large number of forced immigrants who were imported into North America from Africa during the slave trade that emerged during this period. Above all, perhaps, this early wave of migration established the three patterns that were to characterize international migration into the twentieth century.

First, the flow of migrants was largely unrestricted until the consolidations of European borders during the eighteenth and nineteenth centuries would cut down on movements of groups within Europe. During the nineteenth century, several countries in the Americas would pass laws prohibiting the entry of the diseased and other people seen as undesirable, such as the Roma, at the same time that European states were trying to expel them. Nevertheless, for the most part, transoceanic movements of peoples were unaffected by laws restricting immigration.

Secondly, despite some European settlements that were established in the Southern Hemisphere (and eventually the heavy flow of enslaved Africans to Brazil and other parts of South America), the most influential human migrations for Western society were essentially north-to-north movements, occurring within the Northern Hemisphere across an east-west axis—most frequently, from Old World Europe to the receiving areas of the so-called New World of North America.

Finally, the arrival of immigrant European communities frequently displaced Indigenous populations. The latter, in turn, often found it expedient to move deeper into the interior of their lands or were forced to do so.

First Modern Era of Mass Migration

These patterns permeated global migrations through the nineteenth century. The era of forced migration of enslaved Africans came to its conclusion in midcentury, but between 1820 and 1914 more than 44 million Europeans voluntarily migrated to the United States alone—a number 6 million people higher than the total population of France at the time when it was the most populous country in Western Europe. An increasing number of people emigrated from Asia to the Americas, but this movement was still largely within the globe’s Northern Hemispheric corridors. With the arrival of so many newcomers in the Americas, Indigenous populations shrank, not only as percentages of the total populations but also in absolute numbers, as they perished from foreign diseases and were often pushed into less hospitable parts of continents they once controlled. In the United States, many Indigenous people were shoved westward into what was called Indian Territory during the 1830s, ahead of incoming settlers from Europe; others were confined to reservations during the 1880s.

The factors accounting for this mass wave of migration were both sociopolitical and scientific-technological. The middle of the nineteenth century was a particularly turbulent time in Europe, as whole societies were shaken by the revolutions of 1832 and 1848. Large numbers of people began to consider journeying to the Americas to seek better lives and greater freedom. Meanwhile, reforms introduced in Ireland by the British government combined in midcentury with a fungal infection in the potato crop to produce the Great Famine in Ireland between 1845 and 1852, and the beginnings of a mass flight of hundreds of thousands from that island to the United States.

Technological changes also helped further this movement. The emergence of steam-powered ships made the transportation of large numbers of people from Europe and Asia to American ports cheaper, safer, and above all swifter. They cut travel time for transatlantic voyages from as many as five weeks in 1700 to fewer than eight days by the advent of World War I (1914–18). Likewise, the development of transcontinental railroads in the United States after the Civil War provided a means of moving large numbers into the American Midwest and eventually the Far West, where land was plentiful. Industrializing cities needed laborers, and federal troops could provide safety from hostile threats on the frontier by availing themselves of rapidly evolving weapon technologies. In 1840, breech-loading rifles revolutionized combat by replacing muzzle-loading muskets, which for two centuries had limited soldiers to firing only one round per minute, while requiring them to stand and expose themselves to enemy fire while reloading. With breech loaders, soldiers or settlers could fire seven rounds per minute from behind cover, and the rifles were more powerful and more accurate than muskets. By the time of the Civil War, Gatling guns raised firing rates to more than one hundred rounds per minute. It was not a coincidence that shortly afterward, the so-called Indian wars came to their end in North America.

The product of all these developments was a growing tide of migration to the Americas that transformed the US population from its overwhelming British-based stock at the time of independence into the diverse mixture out of which the multicultural American nation would emerge in the twentieth century. Indeed, the influx reached its peak during the early years of the twentieth century, when approximately 3 million immigrants entered the United States every year. The number would have been even higher, had not the unification of Germany between 1860 and 1870, and the resultant growth there of pride and identification with Imperial Germany, slowed significantly what had previously been a major point of origin of migration to the United States.

Finally, scientific discoveries and technological changes had another noteworthy effect during the second half of the nineteenth century that would profoundly affect the nature of global migration a century later. Simply stated, these developments helped lead to the age of world empires. The revolutionary changes in weaponry allowed European forces to relatively easily subdue Indigenous peoples armed only with spears, arrows, bladed weapons, and occasionally obsolete firearms (though in many cases such peoples put up stiff resistance that surprised the better-equipped Europeans). Moreover, the emergence of steam-powered riverboats allowed Europeans to carry their weapons deep into the interiors of regions where previously only coastal areas could be protected. The discovery of quinine as a preventative against malaria allowed Europeans to penetrate tropical regions with protection from a disease that previously was often a greater threat to European armies than Indigenous forces.

Meanwhile, the invention and development of the telegraph and telephone, coupled with the laying of transoceanic cables, allowed heads of state, their generals, and field commanders to be in constant communication. Packaged for empire building, these discoveries, technologies, and inventions changed the nature of politics around the world, and the portion of the earth’s land surfaces peopled by Europeans or under European control jumped from approximately 30 percent in 1820 to more than 80 percent by the time of World War I. By the start of the next world war in 1939, increasing numbers of the non-European subjects of these empires would begin their own south-to-north migrations to the capitals of their imperial rulers.

World War I Through the Cold War

The shift from a predominantly north-to-north to a largely south-to-north pattern of immigration was not the only change involving patterns of global migration during the early years of the twentieth century. The door to largely unrestricted entry into the United States that was beginning to close slowly near the end of the nineteenth century was nearly completely shut. The process began with the passage of US laws forbidding the admission of Chinese immigrants (the Chinese Exclusion Act) and people with mental disabilities. After President William McKinley was assassinated in 1901, anarchists were excluded from the country. A 1917 immigration law required literacy tests. In 1921, a quota system was imposed on immigrants from individual countries, based on the percentages of people from each country who had been residents in the United States in 1910. Three years later, a new law made the quota system even more restrictive by pushing the baseline year back to 1890—a time when very few eastern and southern European immigrants had been in the country. The quota laws naturally favored future immigrants from northern and Western Europe, but they also sharply curtailed the total numbers of immigrants permitted to enter the country legally. Meanwhile, by the first decades of the twentieth century, Indigenous peoples of North America and Australia no longer had to be relocated to make room for new immigrants from abroad. The Indigenous peoples still trying to live in traditional ways had long since been moved to Australia’s Outback and to tribal reservations in the United States and reserves in Canada.

Even without the enactment of US quota restrictions, immigration from Europe to the United States would likely have slackened considerably during the years between the end of World War I and the commencement of World War II. Wartime dislocations, a plague that traveled through Europe after World War I, and the deprivations wrought by the Great Depression contributed to widespread poverty that left few Europeans with sufficient resources to afford transatlantic passage at the same moment the Great Depression was raising unemployment levels to unprecedented heights in the United States. During some Depression years, the United States actually experienced negative net immigration.

Meanwhile, within Europe and neighboring regions, the revolutions of 1917 and subsequent civil war in Russia and the collapse of the Ottoman Empire following World War I produced significant population movements within Europe. An estimated 3 million people from Russia, Poland, and Germany left the collapsing Russian Empire amid its political unrest. Significant numbers of Russian nationals relocated to France. Meanwhile, Muslim immigrants from the Balkan region moved in sizable numbers to Turkey. Likewise, the postwar decision of the newly created League of Nations to make Palestine a homeland destination for Jewish people led to the movement of approximately 400,000 European Jews to that British mandate territory in the Middle East.

The end of World War II produced even more significant movements of peoples, especially on the European continent. Many of the several hundred thousand Eastern European Jews who survived the Holocaust left Europe to migrate to Palestine, even before the independent state of Israel was carved out of it in 1948. Still others emigrated there after 1948, largely stripping Eastern Europe of its once large and prosperous Jewish community. Meanwhile, under the terms of the Potsdam Agreement signed by the principal victors in World War II in 1945, massive, largely forced migrations had already occurred within Europe, when approximately 16 million ethnic German people were sent west from Czechoslovakia and other Eastern European countries. Millions of Polish individuals were also driven west from what had been the eastern Kresy region of Poland, which the Soviet Union acquired as part of its 1939 non-aggression pact with Germany.

The flow of migrants within Europe was not only from east to west. During the same period, hundreds of thousands of individuals of Ukrainian, Lithuanian, Estonian, and Polish origin were expelled from neighboring states to the Soviet Union and parts of its rapidly forming empire in Soviet-occupied Eastern Europe. As the Cold War developed between the Soviet Union and its former wartime allies in the West, other population movements occurred. When the Western Allies decided to unify their zones in occupied Germany and create the independent Federal Republic of Germany, approximately 7 million German civilians fled from Soviet-controlled East Germany into what would become known as West Germany.

Global Migration After 1950

Significant as these wartime and postwar migrations were in reshuffling the peoples of Europe, the migration that would most dramatically affect Europe and North America, and which has most profoundly broken from the pattern of previous migrations, developed elsewhere. It is the one involving the peoples who have migrated from culturally and often religiously different areas in the developing world into the economically more advanced and democratic states of Europe and North America during the second half of the twentieth century. Since the early twenty-first century, forced displacement has become an increasingly significant component of global migration, driven by civil war, political repression, and state collapse. The Syrian civil war, which began in 2011, and Russia’s invasion of Ukraine in 2022 generated millions of refugees, many of whom sought asylum in neighboring countries and across Europe.

The origins of this development in Europe lay largely in that region’s need to rebuild after World War II, which forced much of Western Europe to import large numbers of workers from abroad to fill needed positions. Germany recruited its own "guest workers" in the then-less economically advanced states of southern Europe—most notably, secular Muslim immigrants from Turkey. France turned initially to its possessions in Africa and imported large numbers of foreign workers from Tunisia, Morocco, and Algeria. Britain looked to nations from its former empire in Asia, chiefly in India, from which former British subjects were entitled to immigrate to the United Kingdom as members of the British Commonwealth, until controversy surrounding Britain’s growing "foreign population" eventually caused Britain to pass more restrictive immigration laws.

By the 1950s, the worldwide process of decolonization of European empires was coinciding with Europe’s sustained postwar economic recovery, and its need for still more imported labor. Consequently, ever more immigrants from Europe’s former colonial world were journeying legally to European countries in pursuit of far better earnings than they could receive in their newly independent nations. This trend continued until a worldwide recession that began in 1973 resulted in most European countries restricting further entry. However, by then, workers who had been recruited as temporary employees were becoming permanent members of many European countries’ workforces.

For the most part, the more restrictive European immigration laws did not so much stop immigrant flows as increase the numbers of immigrants entering European countries without authorization. Most continued to come from developing countries in Africa and Asia, and a very high percentage of these people were Muslim in their religious faiths. By the turn of the twenty-first century, it was conservatively estimated that Europe’s Muslim population numbered more than 20 million and was growing at a much faster rate than the rest of the population because of family unification programs that allowed immigrants’ spouses and children to join them. Moreover, the average sizes of Muslim families were sometimes much larger than those of families of European descent.

The population of the United States was also becoming noticeably more multicultural in the period following World War II. Many American soldiers serving in occupied Japan between 1945 and 1955 returned home with Japanese spouses. The advent of the Korean War in 1950 had a similar social outcome, with many American service personnel returning home with Korean spouses. Still later, the Vietnam War that stretched from the mid-1960s to 1975 further enlarged the Asian community in the United States. After the war ended, the US Congress made room in the United States for large numbers of Vietnamese refugees whose service to the United States during the war placed their lives in danger after the fall of Saigon and the withdrawal of American forces.

However, it was the south-to-north pattern in later twentieth-century immigration that had the greatest impact on American society. As a result of the steady emigration of people from Mexico and other countries in Central and South America and the Caribbean, Hispanic immigrants eclipsed African Americans as the largest minority group in the United States by the turn of the twenty-first century. Moreover, by the early years of the new millennium, the unauthorized Hispanic immigrant population in the United States was conservatively estimated to be in the range of between 10 and 12 million people, making the country’s growing Hispanic population a central political issue.

This new wave of immigrants from the developing world to Europe and the United States was becoming politically controversial even before the terrorist attacks on the United States of September 11, 2001, the attack by homegrown Muslim suicide bombers on London’s public transit system in 2005, and the attack by Muslim terrorists on the railroad system of Madrid, Spain, the previous year. Migration became an even more contentious political issue after the large-scale arrival of asylum seekers in Europe beginning in 2015, prompting many governments to tighten asylum laws and strengthen border enforcement. Similar debates emerged in North America, where migration policy increasingly intersected with concerns about national security, economic competition, and humanitarian obligations. However, the presence of these foreign-born populations in the modern Western world became more controversial over time as their numbers continued to grow and as the security concerns of homegrown terrorists and insecure borders were added to the list of concerns that their presence entails.

New theories arose to attempt to explain patterns of world migration. Many economists and sociologists viewed the late-twentieth- and early twenty-first-century immigration trends through the perspective of globalization and its economic repercussions. The phenomenon of immigrants coming to an economically advanced nation in order to work, often sending remittances back to their home country, can be identified throughout history, but its large-scale global implications only began to be explored in the face of the modern waves of world migration. Scholars have also attempted to examine the issue from a less Eurocentric viewpoint, discussing the perceptions of migrants from developing nations and the important differences existing at the national or even subnational level. Theories ranging from neoclassical economics to world systems theory brought new ideas to the study of world migration patterns, with most agreeing that the issue remains of critical importance to humankind politically, economically, and socially. Beginning in the early twenty-first century, scholars and policymakers increasingly examined climate change as a driver of migration. Rising sea levels, prolonged droughts, and extreme weather events contributed to growing displacement in regions such as sub-Saharan Africa, South Asia, and low-lying Pacific island states.

According to the 2024 World Migration Report of the International Organization for Migration (IOM), the US remained a main destination for migrants, with close to 51 million foreign-born individuals residing in the country in 2020. Germany was the second most popular destination, with 16 million migrants in 2020. Globally, there were an estimated 281 million migrants, or 3.6 percent of the population, living in countries that were not their own, which was more than three times the number in 1970. These individuals resided primarily in Europe and Asia, which together accounted for the largest shares of the world’s international migrant population; however, the US still hosted more international migrants than any other individual country, while India was the largest country of origin. Though COVID-19 impacted migration in terms of entry, quarantine, and other requirements, the rate of international remittances increased in the early 2020s, according to World Bank estimates, totaling $831 billion in 2022. Primarily, individuals from India, Mexico, China, the Philippines, and Egypt received the most remittances that year.

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