Could Europe surprise us by growing substantially more than I have predicted? It seems farfetched, but it could happen, either by Europeans curtailing vacations and siesta time to adopt a more workaholic ethos, or by more young women and their partners aligning their views of sex more closely with those of the pope than those of movie stars. Anything's possible, but don't bet on it -- Europeans seem to like their lifestyles just fine, and they've long since given up their dreams of world domination. An unexpected technological breakthrough could also shake things up, though this isn't the sort of thing economists can base predictions on.

To the West, the notion of a world in which the center of global economic gravity lies in Asia may seem unimaginable. But it wouldn't be the first time. As China scholars, who take a long view of history, often point out, China was the world's largest economy for much of the last two millennia. (Chris Patten, the last British governor of Hong Kong, reckons China has been the globe's top economy for 18 of the past 20 centuries.) While Europe was fumbling in the Dark Ages and fighting disastrous religious wars, China cultivated the highest standards of living in the world. Today, the notion of a rising China is, in Chinese eyes, merely a return to the status quo.