China: it has lots of people and they are getting richer. For more than five years that simple reasoning sustained the bulls' case for global growth, and, by extension, commodity prices. Now that support seems to be eroding, at least in the eyes of investors. China's equity market is down 60 per cent year-to-date, in part because of fears that the world's second largest economy is finally beginning to cool.

On the most recent data, the trend is unambiguous. Industrial output growth for August rose at the slowest pace in six years. The long surge in exports, while still growing in excess of 20 per cent a year, is moderating. New homebuyers are hurling rocks in frustration - some metaphorically, others literally - at falling property values.