You can detect a complacency about prospects for the world’s economy in our financial press. But everywhere you look, from Latin America to Asia, and from the US to Europe, you see that bad debt, the very instigator of the worst financial crisis since the Depression, is rumbling again — only this time it’s happening much faster. Yes, some things are different. We’re better prepared (sort of), and have learned from recent experience. But we’re also even more exposed. And it is China whose exposure is the biggest threat.