Immigration can, and already has, offset many of the consequences of population ageing and labour shortages in Europe, a United Nations global study has concluded.
By itself, however, it does not solve the problems of struggling pension programmes.
From 1995 to 2000, the European population would have shrunk by 4.4 million if 5 million migrants had not arrived during that period, says this year's UN World Economic and Social Survey.
Even if 600,000 immigrants a year arrive in Europe between 2000 and 2050, the European population is still likely to decline by 96 million in that period.
"In any event, incoming migration would have to expand at virtually impossible rates to offset declining support ratios, that is workers per retirees", warns the report.
In the future, Spain is projected to have one of the world's highest support ratios.
Historically, most member states have not regarded themselves as receiving countries and people are not generally encouraged to seek citizenship.
"But Germany, Ireland and Latvia have recently streamlined citizenship laws to facilitate naturalization, strengthening migrants' sense of belonging and political participation", says the report.
By: N. Peter Kramer
