It is time to switch fairy tales. For years, market talk has revolved around Goldilocks - shorthand for the belief that economic growth will be "not too hot, not too cold", and allow world markets to move ahead healthily without a big jolt.

After two weeks of heavy volatility, we have switched from Goldilocks to Chicken Little: is the sky about to fall on our heads? Are the many troubling aspects of the world markets going to be enough to generate a systemic collapse, taking the economy with it?