Borders, Oliver, turn out to be extraordinarily permeable.

“Who would take the migrants?”

Any country with a demographic deficit who knows what it is about. I guess the UK would be glad to accept a lot of people from Eastern Europe with the same characteristics as those who are currently moving from East to West Germany. Spain would just love to have them (inward migration now 1.5% of population per annum) - it seems to be migrants from Sub-Saharan Africa that Spain doesn’t want - Italy too (latest data reveal Italy is legalising immigrant workers at a rate of 1.1% of population per annum).

“But how could a migration in so large a scale be feasible?”

I don’t know whether it’s feasible or not, just that the data shows that in some areas it is happening.

“economics causing a demographic meltdown”

Actually I should modify what I said, the two in fact inter-act in a dynamic process. In some cases this process has positive feedback properties, and in others negative feedback ones. Under certain conditions - as we can see in the old DDR case - the economics feeds-back on the demographics to produce meltdown. What I am surprised about is that there is so little interest in this topic, as it seems to me there are a lot of lessons to be learned from what is happening here.

For the recieving country it doesn’t not matter why the immigrants are coming. If the numbers become too high, the borders are closed.

Yes this is the point here. In fact the whole thing seems to me to be ‘path dependent’: ie a small (or at least only moderately large) difference in initial conditions can lead to a huge tilt.

Now the question is could this process repeat itself *across* national frontiers? In one of the baltic states, for example, or of course Bulgaria. I think this is one of the great unknowns of asymmetric demography.

In a situation of natural decline however, you would most likely see an increase in qualification as nations react with automatisation.