The UN announced this week that the world will welcome its seven billionth inhabitant on Halloween this year. A world of seven billion was unthinkable a century ago, when total world population was about as big as India is today. I was sitting in a Chinese history class in college the day world population hit 6 billion. This occasion is seared into my memory because my professor delivered the news while wearing a black armband to mark what she saw as the travesty of world population growth. After her lecture, I left class thinking there wasn’t room for one more person, yet here we are just over a decade later with another billion.
What I’ve come to realize in the interim is that although this number is astounding, how many people are on the planet is far less important for issues of development and conflict than where and who these people are. Meaning, where population growth and decline is concentrated—either at the country level or within states—and the level of education, religion, age, or other identity characteristics of individuals are the real links between demography and political, social, or economic outcomes.
One place where population growth is central to development and security is Afghanistan. The median age in Afghanistan is only 16 years and each woman on average has about 6 children in her lifetime. These numbers mean that over 46 percent of Afghanistan’s population is under the age of 15. As the US plots its exit strategy for Afghanistan, they must also consider the strains that population growth there will continue to place on infrastructure, education, health care, and even governance. Countries with a young age structure like Afghanistan are on average about two and half times more likely to experience the onset of civil conflict than older countries. And even if fertility in Afghanistan falls in the future, those large groups ages 0-5 will require a lot of jobs one day. Experiences in Tunisia, Egypt, and elsewhere so far in 2011 show us what happens when these expectations go unmet.
When groups within countries grow at different rates through natural increase or migration, conflicts over access to economic resources, political power, or cultural influence can arise. One area of the world that has seen tensions over differential growth is Europe. European states have some of the lowest fertility in the world. In stark contrast to Afghanistan, Italy’s median age is over 43 years and over the period 2005-2010 each woman on average had only 1.38 children. Already, over a quarter of the population is above age 60. In light of population aging, Italians, like many other Europeans, perceive that their way of life is under threat by the growth of foreign born or ethnic minorities. One illustration of tension over identity there is the recent outrage over refugees from North Africa, which the anti-immigrant Northern League political party is using to its advantage.
Bringing the where and who together, the UN data show that the divide between the developed and developing world continues to grow. Sub-Saharan Africa is one of the fastest growing regions in the world, and the UN projects that the population will double by 2045, even if the sub-continent is able to reduce fertility from a current average of almost 5 children per woman to just over 3. If fertility stays at its current level, the continent’s population will double a decade earlier, reaching over 1.7 billion by 2035. On the other side of the divide, 42 percent of the world’s population, mostly the developed world, lives in low-fertility countries. Given the ties between fertility and age structure, and age structure and conflict and development, we can project that the economies of very low- and high-fertility countries, which mostly have very mature or very young age structures, will face challenges meeting the needs of their dependents, while those of the middle ages—like many rising powers—will experience high economic growth and a peace dividend. How these shifts translate to global power, peace, and prosperity will be something to watch.