Does Europe need mass immigration?

Europe has received a high net inflow of immigrants since the beginning of this century, but with the economic crisis restrictive policies are being put in place in many countries, and several countries are considering a zero-migration option. Between 2015 and 2050-with zero migration-population would decline in most countries and so would the active population even in the case of increase of activity rates and extension of the retirement age. Moreover the considerable aging of the working population will depress productivity and the rate of innovation. The paper's conclusion is that Europe will have to attract considerable inflows of immigrants in order to sustain a reasonable pattern of growth.