14.1.4 14.15: As less-developed countries become more developed, a demographic transition often occurs.

Populations can sometimes seem as strange and stubborn as individuals. Around the world, governments encourage (or sometimes even coerce) their citizens to reduce their reproductive rates in efforts to check population growth, but they are rarely successful. Yet it seems that when governments stop trying, their countries’ population growth rates slow down all on their own.

Many countries have undergone industrialization, with increases in health, wealth, and education. And in the process, their patterns of population growth follow common paths, marked first by periods of faster growth and later by slower growth. The sequence of changes is remarkably consistent.

Start with a country prior to industrialization. Such countries usually have high birth rates and high death rates, resulting from poor and inefficient systems of food production and distribution, along with a lack of reliable medical care. Food production and health care typically improve as industrialization begins. These improvements inevitably lead to a reduction in the death rate. The birth rate, however, remains relatively high, so the country’s population grows rapidly.

As industrialization continues, further changes occur. Most importantly, the standard of living increases. This results from higher levels of education and employment, and, in conjunction with improved health care, this finally causes a reduction in the birth rate. The new, lower birth rate then slows the population’s growth. The progression from

• 1. high birth rates and high death rates (slow population growth) to
• 2. high birth rates and low death rates (fast population growth) to
• 3. low birth rates and low death rates (slow population growth)

is called the demographic transition (FIGURE 14-24).

The demographic transition can take decades to complete, so it is not always easy to identify it as it occurs. A survey of countries around the world reveals that many are at different points along the transition. Sweden, for example, has a low fertility rate (1.7 children born per woman) and a low death rate (10.4 deaths per 1,000 people). At the other extreme, Nigeria has a very high fertility rate (5.5 children born per woman) and death rate (17.2 deaths per 1,000). Mexico, in the midst of a clear demographic transition, has a moderately high fertility rate (2.45 children born per woman) yet a very low death rate (4.7 deaths per 1,000).

In the past few decades, the demographic transition has been completed in Japan, Australia, the United States, Canada, and most of Europe, leading to a slowing of population growth. In Mexico, Brazil, Southeast Asia, and most of Africa, on the other hand, the transition is not complete and population growth is still dangerously fast.

The demographic transition illustrates how health, wealth, and education can lead to a reduction in the birth rate without direct government interventions. But because more than three-quarters of the world’s population lives in developing countries and less than a quarter in developed countries, the slowed population growth that generally accompanies the demographic transition is unlikely to be sufficient to keep the world population at a manageable level. Instead, world population growth will continue to rise quickly. What are the potential consequences of such explosive growth? We explore this next.