If you want a short, sharp introduction to the topic of global ageing, the latest issue of The Economist is just the ticket. It covers the demography and economics of ageing (in the developed world) and concludes that "the consequences will be scary". Finally the message is beginning to sink in. You can download a PDF if you sign up for a free account.It's worth it.

Some highlights:

The end of retirement -- in its leader for the special issue, The Economist points out that Otto von Bismarck created the modern pension system in Prussia in 1889. Workers over 70 would receive a government payment -- but their life expectancy was only 45, so it was a good deal for the government. Nowadays the average American retires at 64 and can expect to live for another 16 years. The financial pressure of paying pensions to 20% of the population is going to force us back to "the pre-Bismarckian world where work had no formal stopping point".

A slow-burning fuse: why the world is getting older explained in simple language. The financial effects will be severe: a declining workforce, a possible asset meltdown, stingier governments.

"People in rich countries will have to be weaned off the expectation that pensions will become ever more generous and health care ever more all-encompassing. Since they now live so much longer, and mostly in good health, they will have to accept that they must also work for longer and that their pensions will be smaller."

Suffer the little children: most of the rich world is short of babies. But it is remarkably difficult to persuade women to have more. Flexible labour markets help, but they are not a panacea.

"... having children is a personal choice, and if people really do not want them there is nothing governments can do. The UN expects fertility in developed countries to recover somewhat by 2050, to 1.8 children per woman, but many experts think that forecast is too optimistic."

A world of Methuselahs: the benefits, and the costs, of living longer. This section reviews the age-old dream of eternal youth, or at least, a very long and healthy life. The problem faced by modern economies is that people are living much longer and are healthier for longer. But older people inevitably require more health care. Who will manage it? How will it be paid for?

Scrimp and save: pensions will have to become far less generous. Life for the elderly was good in the 1980s, when there were only 20 people of retirement age for every 100 people of working age. But governments cannot afford to support the elderly of 2050 in the same cushy lifestyle because there will be 45 old codgers for every 100 workers.

"So if state pensions are having to be reined back, private pensions are getting meaner, riskier and less predictable, and money saved for retirement is threatened by financial crises, what is the man in the street to do to make ends meet? The only thing for it, say all the experts in unison, is to carry on working."

China's predicament: getting old before you get rich. Because of the one-child policy, China is ageing extraordinary fast. In fact, in some areas there are already labour shortages because there are not enough young workers.

The conclusion of the survey is sobering. The world is moving into unknown territory. Ageing will affect the world in profound and unpredictable ways, ranging from the economy to geopolitics. Every country with ZPG will pay the consequences for not having children. With one significant exception:

"Because America’s population will still be growing when that of most other developed countries is shrinking, America will be the only developed country that still matters geopolitically."