Think America's debates about Social Security are troublesome for the future? Consider yourself lucky.

Over the next generation, it seems entirely likely — indeed, all but inevitable — that a large fraction of humanity, peopling countries within the grouping often termed emerging market economies, will find themselves coping with the phenomenon of population aging on income levels far lower than those yet witnessed in any society with comparable degrees of graying. For such countries, the social and economic consequences of aging could be harsh — and the options for mitigating the adverse effects of population aging may be fairly limited. In some of these countries, population aging could potentially emerge as a factor appreciably constraining long-term growth and development.

As we will detail in the next few pages, rapid and pronounced population aging represents a highly uneven, largely unappreciated, and as yet almost entirely undiscounted long-term risk for the world’s emerging markets.

Think about the fact that US prosperity is now substantially linked to Chinese investment. Project forward 30 years. Now put yourself in China's shoes: do you care for the elderly, and let America crash? Or do you let the state fail in order to prop up the US? Can you imagine the US pressuring China to block local expenditures for universal health care?

Did you read the Niall Ferguson piece?