What an interesting couple of weeks. In short order we have had the collapse of the sub-prime mortgage market in the US, an equities setback sparked by worries that Chinese authorities would clamp down on stock market speculation and a particularly severe tornado that ripped apart an Alabama town, leaving debris and deaths in its wake. What do these disparate events tell us?

That a move in Shanghai can wipe out two months of stock market returns around the world in a couple of days tells us something about China and about markets. Anything that happens in China is news today. Yet market regulatory moves will barely impact what really matters, which is China's economic growth.