All the wealth in the world adds up to just under $200 trillion dollars (the world economy is worth $60 trillion a year, as we mentioned in a recent story), most of which was created in the last two centuries and two-thirds of which is owned by Westerners, who represent just a fifth of the population. That’s a thumb-sketch of the world economy given by economic historian Niall Ferguson in a recent TED talk called ‘The 6 killer apps of prosperity’. What explains this ‘great divergence’? Not geography or national character, says Ferguson, but a half-dozen ideas and institutions that set the west apart from the rest: competition, the scientific revolution, property rights, modern medicine, the consumer society and the work ethic. “Any society can adopt these institutions,” says Ferguson - and in fact it’s already happening. The average American, who used to be 20 times wealthier than the average Chinese, is now five times wealthier than the average Chinese, and soon the multiple will be just 2.5. Indeed, says Ferguson, China is tipped to become the world’s biggest economy in 2016.