The recent print edition of The Economist included an interesting summary of the world’s demographic issues. It points out that much of the effect of population growth depends on where that growth occurs and on various other factors such as the number of working age people in a particular country. On the whole the countries which still have fertility rates above replacement level are the countries that are causing only a tiny fraction of world pollution, and about half of the 2.3 billion increase in the world’s population over the next 40 years will in fact be in Africa:
...it does not automatically follow that the more people there are, the worse the damage. In 2007 Americans and Australians emitted almost 20 tonnes of carbon dioxide each. In contrast, more than 60 countries—including the vast majority of African ones—emitted less than 1 tonne per person...Most of the world’s population growth in the next 20 years will occur in countries that make the smallest contribution to greenhouse gases.
Often the population growth debate and hype seems to have little regard for such details and the man on the street is left with the general impression that a huge crisis looms ahead for us all and the environment is slowly melting away. However, it is now common knowledge that Earth’s population is aging, with 40% of countries having fertility rates below replacement level, including Brazil, Thailand, Tunisia and much of Europe and East Asia. Incredibly, by 2050 Japan will be the oldest society the world has ever known. This blog regularly recounts the effect of low fertility on various countries, and this article gives a good summary.
By 2050 [Europe] will have three dependents for every four adults, so will shoulder a large burden of ageing, which even sustained increases in fertility would fail to reverse for decades. This will cause disturbing policy implications in the provision of pensions and health care, which rely on continuing healthy tax revenues from the working population.
At least these countries are rich enough to make such provision. Not so China. With its fertility artificially suppressed by the one-child policy, it is ageing at an unprecedented rate...This will bring an abrupt end to its cheap-labour manufacturing. Its dependency ratio will rise from 38 to 64 by 2050, the sharpest rise in the world. Add in the country’s sexual imbalances—after a decade of sex-selective abortions, China will have 96.5m men in their 20s in 2025 but only 80.3m young women—and demography may become the gravest problem the Communist Party has to face.
The world has reaped the demographic dividends of the baby boomer generation which brought with it a high ratio of working age people to dependents. Now it has to figure out how to support an increasingly unbalanced society. Not to mention how countries which have artificially imbalanced their populations through sex selection will cope. It seems so sad that in China so many men will have no chance of having a wife and family - and that this situation is largely of the country's own making.