Rather than bridges, the construction of insurmountable walls and fences – such as built or to be built on sections of the borders of Hungary and the US – seems to characterize the immigration policy of most developed welfare states today, with the aim of keeping out migrants. Usually, economic migrants without the prospect of a job are not welcome at all, while refugees have to fit a very narrowly defined set of criteria before they are admitted into a developed country. As a consequence of these restrictions, North America, Japan, and many EU countries have become the home of large numbers of illegal immigrants. A solution to this problem is not in sight. Not deporting these poorly educated and unskilled immigrants is one thing, but giving them the same rights and benefits as the resident population is quite another matter. Such a policy might well bankrupt existing welfare systems. The problem is that the earning capacity of most present-day immigrants from the developing world, be it first or second generation, is usually well below average. As a consequence, and as soon as they have obtained a legal status, such immigrants automatically receive more in welfare payments and other subsidies than they contribute to the public purse in taxes and premiums.

The hostile attitude of modern welfare states towards unselected immigrants makes it much more difficult for Africa and Asia to follow the European economic growth model of the past. Per capita, Europa was able to spend more on education, better housing and public hygiene, because it had the opportunity to export part of its population to other continents. Such a migration escape hatch no longer exists.

Until 1850, intercontinental migration was still relatively modest in volume due to the limited technical and financial possibilities for transporting massive numbers of migrants across the oceans. After 1850, however, these limitations were considerably reduced and it became possible to transport more European migrants to other continents in a decade than in any one of the three previous centuries. At the same time, emigration out of Asia and Africa was almost cut off due to the abolition of the intercontinental slave trade and to the strict limitations placed on the migration of indentured labourers from Asia.

Before 1850, intercontinental migration out of Europe and the slave trade out of Africa might have alleviated some of the hardships caused by bad harvests and low agricultural productivity in the sending regions, but the numbers were too small to have a wider economic impact. Possible exceptions are some regions in England, Scotland and Ireland, which contributed about half of the intercontinental migrants during the first three centuries of intercontinental migration. Some of these regions were also the first to industrialize and that seems to suggest that emigration was a major contributing factor. Does this mean that the suppression of the slave trade out of Africa and the limitations placed on emigration out of Asia may have reduced human suffering, but retarded the process of industrialization of these continents? Such a conclusion is not supported by historical evidence. The history of Portugal is a case in point. During the early modern period this country had an emigration rate similar to that of Britain, but it industrialized relatively late. Yet, it stands to reason to assume that Portugal would have industrialized even more slowly had it not been able to send part of its population abroad.

There seems little doubt that migration must have been an important factor in explaining the dramatic rise in economic growth. During the nineteenth century, Europeans started to dominate intercontinental migration in numbers that had been hitherto unknown, in exactly the same period during which Europe started to industrialize. Between 1800 and 1960 at least 61 million Europeans participated in intercontinental migration. North America was the main recipient of these migrants: 41 million, or about 70% of the European migrants, went to the United States and Canada. Other European migrants went to South America (12%), to South Africa, Australia and New Zealand (9%) and to the Asian part of Russia (9%).

Asia and Africa have had far fewer opportunities to send some of their excess population to other continents. After 1800, about five to six million Asians and Africans took part in these migrations. About half of this number – approximately three million – were African slaves, a migratory movement that constituted a continuation of the slave trade, the most voluminous intercontinental migration stream before 1800. In spite of the many attempts to suppress the slave trade, most of the Africans who moved or were moved to another continent during the nineteenth century were still slaves: only some 100,000–200,000 went as free labour migrants. In addition to the African slave trade, a new stream of migrants started to participate in intercontinental migration: Asian indentured labourers, totalling about 1.3 million. Half of these indentured labourers went to the plantations in the Americas, in part to replace the slaves. The other half went to South Africa, La Réunion, Mauritius, Australia, Fiji and Uganda.

In summing these figures we arrive at a grand total of about 65 million European intercontinental migrants and 15 million Africans and Asians. These figures show that the relatively small population of Europe has used the ‘emigration escape hatch’ in a far more substantial way than the inhabitants of other continents. Even if we limit ourselves to the period after the Second World War, the dominance of Europeans remains impressive. During the period 1945 to 1960, the total number of intercontinental migrants from Europe came to about seven million whilst the number of non-European migrants amounted to less than half of that. Of course, we should keep in mind that all these numbers are imprecise; they are only used in order to roughly quantify the relative volume of the participation in intercontinental migrations by Europeans, Africans and Asians.

Demography usually provides us with the most realistic answer to the question as to whether these migrations were successful. The demographic data reveal the existence of two migration circuits. By entering the first circuit, the migrants were able to increase their numbers by demographic growth, to emancipate themselves from hunger and disease, and to improve their living conditions. Most early modern migrants seem to have been able to fulfil their dreams, i.e. sufficient food for all members of the family, the ownership of a piece of land, the opportunity to marry early, and to have many surviving children, who in turn also would be able to own a piece of land. The first migration circuit allowed its migrants to double in numbers within a period of 20 to 30 years. As an extreme case, colonial French Canada should be mentioned, where half of the population consisted of people below the age of 15, while the average number of surviving children per mother was about eight. The slaves and indentured migrants from Africa and Asia entered a second intercontinental migration circuit, where the conditions were less favourable than in the first one. Sufficient food might not have been a problem, but unlike most migrants of the first circuit the slaves had no say in their destination nor in the choice of employer. By being moved from Africa to the tropical parts of the New World, the slaves did not improve, but probably shortened, their life expectancy and they did not have more, but fewer children. It took centuries for the Africans overseas to overcome this demographic disadvantage, with the exception of the slaves who had been brought to North America. During the nineteenth century, however, the conditions of the second circuit improved, allowing the migrating Asians to benefit from demographic growth almost right from the start. In addition, the indentured labourers could choose from a limited number of destinations and their transportation was paid for both ways: to their destination as well as going back.

Considering the pressing demand for labour in the expanding cash crop production in the tropical regions during the first half of the nineteenth century, there is little doubt that the second migration circuit would have grown more rapidly than the first had the slave trade from Africa not been outlawed. The ending of the slave trade from Africa stimulated slave owners in the New World to take better care of their slaves by improving their working and living conditions. That explains why, during the course of the nineteenth century, the second migration circuit lost many of the disadvantages that had made it so different from the first. The transportation of contract labourers from India to the plantation colonies became subject to more detailed government regulations than that of emigrants leaving Europe for North America. In addition, the living and working conditions of contract labourers in the Caribbean, Uganda, South Africa, Mauritius and Fiji were carefully monitored by special immigration departments.

After 1800, the two migration systems did remain separate and offered different opportunities to migrants, but both systems allowed an escape from poverty, disease and starvation. However, one important difference between the two circuits remained: the Asian and African migrants were too poor to pay their transportation and remained dependent on a system by which, in return for a paid passage, the migrants had no choice in selecting their employer, the type of work and the amount of labour they had to offer.

Today, both intercontinental migration circuits are still in existence. In the first migration circuit, intercontinental migrants move between Europe, North and South America, South Africa, Japan, Australia and New Zealand. They pay for their own transportation and select their own living quarters as well as the number of working hours. The migrants of the second migration circuit move mainly between Asia, the Middle East, and Africa and usually a prepaid passage is still part of the migration arrangement.

However, more and more migrants from Asia and Africa are able to pay their own way. Rather than limiting themselves to the traditional destinations of the second circuit, some of these migrants now opt for those of the first circuit, which offer better conditions, more choices and far higher rewards. However, having overcome the financial barrier, migrants from the developing world now detect a second one: the lack of education, skills and knowledge of the local language. Without these, many migrants from Africa and Asia almost certainly will become a burden on the public purse in the welfare states of the developed world, and that explains why walls, fences and strict border controls are now put in their way.