These are only projections, of course. Lifespans will no doubt continue to stretch and immigration rules may change. What is striking, though, is the gulf between the fertility rate in the United States and other rich countries. American women today can expect to have an average of 2.1 children. That is the number needed to keep a population stable, so observers sometimes take it as a given and say that America's population growth is entirely due to immigration. This obscures the point: for every big advanced country besides America and Israel, the alternative to "replacement rate" fertility is a baby bust.
The fertility rate in the EU is 1.47—well below replacement. By 2010, deaths there are expected to start outnumbering births, so from that point immigration will account for more than all its growth. And that average hides countries that have seen an astonishing collapse in the willingness of their citizens to breed. The fertility rate in Italy and Spain is 1.28, which, without immigration, would cause the number of Spaniards and Italians to halve in 42 years.
The Economist explains how the rate of population growth in poor populations is due to infant mortality and the need to care for the elderly imposed on the children of the family. There are other reasons:
...many Westerners fret that they cannot afford to have them. University is expensive, and if Mum (or Mom) decides to stay home, the household must forgo the salary she used to earn. Add to this the sudden halt to a life of carefree first-world hedonism, and it is no wonder that birth rates have plummeted in all rich countries.
But much less so in America. Why should this be? Religion plays a role, argues Mr Klineberg. Americans are more devout than Europeans, if church attendance is any guide, and their faith colours their worldview. Don Iloff, a spokesman for Lakewood Church (and Victoria Osteen's brother), agrees. Faith begets hope, he says, and if you have hope for the future, you are more likely to want to bring children into the world.
Polls certainly suggest that Americans are more optimistic than people in most other countries. Philip Morgan, a sociologist at Duke University, and Miles Taylor, a population expert at the University of North Carolina, cite several other possible factors. Birth rates are lower in more patriarchal rich countries, such as Japan and Italy, than in places where the sexes are more equal, such as America and Scandinavia. Perhaps the knowledge that Dad will help with the housework makes women more willing to have children.
And there's more good news for Americans besides their relative lack of hedonism and religious beliefs bestowing hope on their inhabitants. Degenerate Europeans are matched in their low birth rates by hard-working Orientals.
America's wide open spaces also make child-rearing more attractive. Bringing up a large family in a tiny Japanese apartment is a struggle, even if you can fold away your bed during the day. The world's lowest fertility rates are in super-crowded Hong Kong (0.95), Macau (1.02) and Singapore (1.06). In America the average family-home has doubled in size in the past half-century, from 1,000 square feet (93 square metres) in 1950 to 2,100 square feet in 2001.
America's coastal areas are fairly densely settled, but families who cannot afford a spacious home with a garden in Connecticut or California can move somewhere cheaper. They often do, one reason why the mean centre of America's population—ie, the point at which an imaginary, flat United States would balance if only the people on it weighed anything—keeps moving south and west. In 1800 it was still near the eastern seaboard, in Maryland. By 2000 it was in Phelps County, Missouri, and heading for Oklahoma.
Given present trends, the EU will have fewer than two working adults for every retired person, while America will have three. Who then will pay for the lavish cradle-to-grave nanny-states the Eurotrash have voted themselves?
Much as the failing EU project disdains American success and looks elsewhere for models, the answer is probably not going to come from any other major rising economic leader of the world economy.
Can the world cope with a relentlessly expanding America? Many non-Americans will shudder at the prospect, but which alternative superpower would they prefer? China? If demography is destiny, they will not have to find out what a Chinese hyperpower looks like: the fertility rate in China is only 1.7, and there are almost no immigrants.
So the snobbish EU layabout faineants can look down their long noses at America for a long time to come, but they will be receding economically in America's rear-view mirror.