China Couldn’t Keep Growing Like Mad Forever

China, not the U.S., is the world’s largest economy. Though the U.S. is still tops when measured at market-exchange rates, China is about 20 percent larger after adjusting for the lower cost of goods and services there. The latter metric is what really counts, both in terms of standards of living and, probably, in terms of military purchasing power.

With four times as many people as the U.S., it makes sense that China would eventually have a larger economy; it’s unlikely that any industrialized country — including the U.S. — can maintain a fourfold productivity advantage over another forever. For China, just being bigger than the U.S. is a pretty low bar. But that leaves the question of just how dominant China will eventually be in the world economy.