New Scientist: The population explosion began in Europe in the 18th century and sent people all around the world. Now Europe faces a population implosion with the lowest fertility rate and highest elderly population in the world. European countries will not be able to sustain their welfare state systems that depend of younger workers supporting older people. Some countries are called hyper-ageing. That's how bad it is.

You would think that a smaller, declining population would be better, let's say, for the environment. But the per-person cost for a country's intrastructure actually increases as the population declines. Immigration may not be the answer.

All this is not new. The trend has been observed for some time, but it has been ignored. Back when I read sociology, the chapter of population always warned of a population explosing, and a future world population of 10 billion.