Rates of migration rose in the 20th century in response to both pull and push factors. The pull factors came in the form of easy air travel and improved land and sea routes, the push factors from armed conflict and political, ethnic or religious persecution, from poverty, and also from natural disasters such as droughts and floods.
Patterns of migration over the last century or so have been varied and complex. Migrant flows between countries often drew the most attention, especially where national identities were involved. But much migration was within countries, in particular from countryside to city, as the rate of industrialization increased. For many young men, service in the army, whether in war or in peacetime conscription, broke the village connection. Extensive migration within the USA reflected both economic opportunity and patterns of retirement. There were major population shifts from the Rust Belt zones of the North-East and Midwest (where heavy industry was in decline) to the Sun Belt of the West and South-West, as well as to Florida and North Carolina.
Economies varied widely as to how migrants were treated. The huge refugee camps seen in parts of the Middle East and East Africa contrast with the USA, for example, which has attracted large numbers of economic migrants from Latin America. There were similar flows of Turkish workers to West Germany, and Portuguese to France, from the 1950s. By 1973, 12 per cent of the West German labour force was foreign-born. Foreign nationals outnumber the local workforce in the rich but not populous states of the Persian Gulf.
The UN’s Refugee Convention of 1951 defines a refugee as someone forced to flee their country because of persecution, war or violence, or who suffers a well-founded fear of persecution for reasons of race, religion, nationality, political opinion or membership of a particular social group. Wars throughout the 20th and 21st centuries have led to great flows of refugees. The Second World War alone created an estimated 60 million. In 2004, it was estimated that there were 37.5 million refugees worldwide. By the end of 2014, the figure had risen to 60 million, nearly two-thirds of them internally displaced. Most countries have signed up to the Refugee Convention, and so theoretically recognize their obligations to grant asylum to, and look after, refugees who end up within their borders. At the same time many countries make considerable efforts to prevent refugees from arriving on their shores in the first place.
These migrant workers often do not settle permanently – indeed, the Germans referred to them as Gastarbeiter (‘guest workers’). This contrasts with those migrants fleeing persecution, who cannot return home. Examples include the Huguenots – the French Protestants expelled from France by the Catholic Louis XIV – who settled in England in the late 17th century, and the Jews who fled Nazi Germany in the 1930s.
As environmental factors and military conflicts continue to stimulate flows of migration, nation-states around the world will face increasing political and economic challenges in absorbing different population groups and cultures. In facing these challenges, we are also reminded that we all share a common humanity, and that we all live on the same small planet, which we happen to have divided up with often arbitrary lines called borders.