Migration-Fertility Trade-Off and Aging in Stable Populations

Juha Alho, University of Joensuu

Fertility is below the replacement level in all European countries, and population growth is expected to decline. Increasing life expectancy will accentuate concomitant aging. Migration has been seen as a possible means to decelerate aging. We introduce a stable open population model in which net-migration is proportional to births. In this case the migration-fertility trade-off can be studied easily. We show that while migration can increase the growth rate, and tend to make the age-distribution younger, it also has an opposite effect due to its typical age pattern. We capture the effect of the age-pattern of net-migration in a migration survivor function. The effect of net-migration on growth is quantified with data from 17 European countries. We show that some countries already have a level of migration that will lead to stationarity. For countries with asymptotically declining populations, migration still provides opportunities for slowing down aging.