Unbridled immigration could trigger social conflicts in the host country, for example if the immigrants put additional pressure on the labour market, or ethnic, language and cultural differences between them and the resident population lead to tension. People have always left their homelands in search of a better life. Expanding national economies, for example, have always had a great vortex effect. But never before have migration movements had such a dimension as now. This figure embraces politically persecuted refugees, war refugees, legal work migrants and, in particular, people who seek better opportunities in foreign lands.
Migration still takes place mainly between developing countries.
But ever more people are pressing out of the developing countries into the rich centres of the North. Population pressure and the overtaxing of natural resources that goes with it are one reason for the migratory movements. Armed conflicts, political persecution and the widening prosperity gap between developing and industrialised countries are further causes. But whereas in the 1950s and 1960s most of the host countries still had a demand for foreign workers, their readiness and capability to receive them has diminished noticeably in recent decades. Finally, the rapid population growth in developing countries of the South is causing more and more environmental damage.