Seven population trends that hold the key to good public policies

While governments and institutions grapple with economic uncertainty and volatility, an important factor is often overlooked: demography. Demographic trends can provide relative certainty in the near term to deal with debt, taxes, unemployment and entitlements, to name a few. Dismissal of these major demographic trends can result in ill-conceived policies, unsustainable programmes and squandered resources.

First, at an estimated seven billion, the world's population is growing at 1.1 per cent annually, or 78 million people, half the peak level of 2.1 per cent in the late 1960s. Although the world's growth rate is continuing to slow due to declining birth rates, the eight billion mark will probably be reached by 2025. This growth will increase the number of working-age people by 610 million (13 per cent), and those aged 65 and older by 290 million (52 per cent).

Second, nearly all the world's annual demographic growth is occurring in less developed regions. Because of its much higher growth, India's juggernaut population - larger than all the developed regions combined - is expected to overtake China's in a decade. Among more developed regions, the US is contributing the most to population growth, 3 per cent.

Yet 54 per cent of the world's gross domestic product comes from the 10 largest economies of the more developed countries. Collectively, these countries - led by the US, Japan and Germany - represent 14 per cent of world population, although it is expected to fall to 11 per cent by mid-century.

Third, populations are becoming more urbanised, and many cities are close to coastlines, making them more vulnerable to climate change.

Fourth, global fertility continues to decline. Today, the average number of children per woman globally is 2.5, about half the level 50 years ago. But behind such averages lie considerable regional variations. Fertility rates for most developed countries and increasing numbers of developing countries are at or below replacement levels. By mid-century, the populations of three dozen countries - including China, Germany, Japan and Russia - are expected to be lower than they are today. By contrast, African birth rates stand at more than four children per woman. Such fertility rates translate into rapid population growth for most sub-Saharan countries in the coming decades.