A growing population adds another billion people but it is also rapidly ageing: a child born next year will live 6 months longer than one born today. While migration helps to rebalance, increasing dependency ratios challenge many.
While there are a number of different views on total population growth over the next 50 years, no one disagrees that this growth is going to be imbalanced. Be it ageing, fertility or geography, we are increasingly going to have more people in the places and demographic zones where we are least comfortable. Dependency ratios in some countries are fast moving into unsustainable areas; thanks to climate change we are going to see significantly increased migration as the system across many societies seeks to rebalance itself. This in turn will lead to economic, political and social stresses around the world, bringing a greater pressure on the overall system in the next decade.
The latest medium UN projections see the current global population of 7.4bn rising to 8.5bn by 2030, 9.7bn by 2050 and over 11bn by 2100. Overall, with better use of food and land, this is thought possible. However, regionally the numbers and speed of increase vary considerably. In Europe, the natural population is actually set to decline. Other countries with a naturally declining population include Japan, South Korea, Taiwan and Singapore. In all, the populations of 48 countries or areas in the world are expected to decrease between 2015 and 2050.
By contrast, Africa is growing steadily. Africa’s share of global population is projected to rise 25 per cent by 2050 and 39 per cent by 2100, a staggering 4.9bn. Elsewhere, the trend is somewhere in between: In North America the population is expected to reach 500m by the end of the century; In South America 721m. Across Asia as whole, we will see 4.9bn by the end of the century. Overall we will be adding an average of 60m people a year to the planet between now and 2050. While most of the growth is evidently coming from Africa, other expanding nations such as India are experiencing what they see as more manageable growth. Those countries that are seeing population decline however face significant structural issues for the future. If they are to maintain sustained economic growth, one of the biggest challenges is how to achieve this with an increasingly imbalanced domestic population.
There are three core drivers of population growth: ageing, fertility and migration. It is the first of these that is most visible in most societies today. One of the great successes of the last 50 years has come from improved healthcare; we are all living longer. 900m people, around 12% of the world’s population, are aged over 60 (projected to rise to 1.4 billion by 2030). While most of the overall increase will come from health improvements achieved in bringing the average in Africa up from 50, it will be in Asia, America and Europe where the elderly will be most visible.
In pretty much every country the number of babies being born per family is on the decrease. This is widely seen to be a good thing as it both reflects better healthcare and puts a brake on runaway long-term population growth. Infant mortality is decreasing and so families no longer see the need to have so many children to stand a chance of them making it through to adulthood. The single biggest factor in reducing fertility is widely seen to be female education, a major focus for many governments worldwide for the past 50 years and a priority Millennium Development Goal; women who are empowered through education tend to have fewer children and have them later
China’s One Child Policy was introduced in 1978 to manage population growth. Although it has many detractors, many see that it has worked but maybe too well. During this time the population growth has been brought under control but there have been consequences. As a result, the policy is now for two children. China has too many men, too many old people, and too few young people, “a huge crushing demographic crisis. If people don’t start having more children, they’re going to have a vastly diminished workforce to support a huge aging population."
Bringing all this together, within and across countries, demographers look at the balance of society by calculating dependency ratios. These are a measure showing the number of dependents (aged 0-14 and over the age of 65) to the total population (aged 15-64), the number of people being supported by the system in proportion to the population available to work and so pay taxes into the system.
Concern is raised when the total ratio increases beyond 60% and the elderly ratio is more than half of that, showing not only a high level of social burden, but one skewed by an ageing population. As the elderly dependency ratio globally is set to double by 2050, a good number of countries will be worried. Similarly, the potential support ratio (PSR) calculates the number of working age people per single elderly person. By 2050, many countries are expected to have PSRs below 2, underscoring the fiscal and political pressures that the health care systems, as well as the old-age and social protection systems, of many countries are likely to face in the not-too-distant future.
Shorter-term options for rebalancing and imbalanced population are few and perhaps the most visible is migration. Around one in seven people today are migrants: net migration is projected to account for 82 per cent of population growth in the high-income countries. Migration is an increasingly political concern globally; although the current conflict-driven movement of people out of Syria is ever present on our TV screens, globally the great majority of displaced people have been uprooted by weather-related disasters.
As the rate of growth globally drops, thanks to longer life spans, and we continue to move towards a steady state of around 2bn babies on the planet, what remains uncertain is how societies will seek to cope with high dependency ratios and low potential support ratios, and the role we will want to give increased migration as the 21st Century’s primary population balancing mechanism.