The long-term role of migration on European country population size

Michael Murphy, London School of Economics and Political Science (LSE)

We estimate the impact of migration on population size in 11 European countries that include over half the population of Western, Northern and Southern Europe from the middle of the 19th century to the present. We provide estimates of the population sizes that would have been observed under the assumption of zero net migration from various start dates over this extended period and decompose population growth into the contribution of (1) migrants together with their descendants and (2) natural increase in the absence of migration. We justify our assumption that the long-term demographic impact of migrant populations has been similar to that of cohorts of the same age and sex who did not move over this period. We use information from the Human Mortality Database (HMD) . We attribute the contribution of current population size to net migration in specific historical time segments. If it had experienced no migration throughout the late 19th and whole of 20th centuries, Italy would have about 16 million people more, and Scotland would be double its current size. In contrast, France would have 14 million fewer people and Switzerland would be about one third smaller if net migration had been zero. Migration has a substantial effect of population growth across these countries and tends to reduce disparities in growth rates over the long term, a finding we relate to demographic transition. For most of the countries considered, population sizes would be smaller than the actual values in 2000 if there had been no migration over the past 150 years, but more recent trends suggest a qualitatively different future. Reference: Murphy, Michael (2016) The Impact of Migration on Long-Term European Population Trends, 1850 to Present. Population and Development Review Vol 42, Issue 2, pages 225-244