Chinese local governments are swimming in debt. By official accounts, that debt totals $4.5 trillion. By unofficial estimates, it could be as large as $10 trillion…China has long borrowed heavily to build and then counted on breakneck economic growth to pay it back. The script: Sell vast amounts of land to developers, borrow to subsidise construction, and jobs and new cities will result. It was a model that helped China build its skyscrapers and high-speed rail lines and ushered in an era of prosperity.