In my last post, I cited a recent CIS study showing that mass immigration only marginally effects America’s age structure and has little or no impact on Social Security revenue.

What holds for the US holds for Europe -- and then some.

Every nation in Europe has a shrinking and aging population. Some nations, like Germany and Italy, are in demographic freefall. This is not good news for Europe’s long term economic prospects, and has led many to worry that the post-war providential state is about to implode.

With that in mind, a little remarked year 2000 UN study set itself the question: “Is replacement migration [i.e., mass immigration] a solution to declining and aging populations?”

The answer: yes, if you don’t mind 1.4 billion new immigrants [PDF] .

That’s the number of immigrants the nations of Europe would need to admit between 1995 and 2050 if they were to maintain the population age structure of the 1990s – i.e., the same ratio of working age adults to elderly and retired people.

A dramatic proposition, to say the least. The study notes:

By 2050, these larger migration flows would result in populations where the proportion of post-1995 migrants and their descendants would range between 59 per cent and 99 per cent. Such high levels of migration have not been observed in the past for any of these countries or regions.

“It seems extremely unlikely,” the study tersely concludes, “that such flows could happen in these countries in the foreseeable future.”

You don’t say.

Europe’s headed for crisis and immigration can do nothing to avert it. All that remains is to cushion the blow. To do so, the UN study recommends a number of measures: pension cuts, a later retirement age, increases in worker and employer contributions (i.e., higher taxes), and moderate immigration with assimilation.

What it does not mention – but what is at least as important for Europe’s long term prospects as any other measure – are policies promoting higher birth rates. If Europe is to survive, it must first reproduce.

The post-war welfare state was founded on a fallacy of permanence. Over the next generation, European elites will be faced with some very tough choices. It would be better for them and everyone else if they made these choices early.

So far, there's no sign of that happening.