Webinar on PRB's 2012 World Population Data Sheet


(August 2012) Nearly all future population growth will be in the world's less developed countries, and the poorest of these countries will see the greatest percentage increase, according to Carl Haub, PRB senior demographer and co-author of PRB's 2012 World Population Data Sheet.

Even though declines in birth rates have been virtually universal across countries, some of the poorest countries have shown little if any decline. "What we are left with is rapid population growth in countries that can least afford it," said Haub during a July 19, 2012, webinar to mark the data sheet's release.

In contrast, developed countries as a whole will experience little or no population growth in this century, and much of that growth will be from immigration from less developed countries. Europe's population is expected to decline slightly by 2050, reflecting low fertility. But this slight size change hides a dramatic shift toward countries with unprecedented shares of elderly people, Haub noted.

He compared Tanzania and Spain to show the clear contrasts between less developed and more developed countries, known as "the demographic divide." The two countries have almost the same population size today: Tanzania's population is 48 million and Spain's is 46 million. But Tanzania has a youthful population, with 45 percent of Tanzanians under age 15. In contrast, Spain has only 15 percent of its population under age 15.

Projections to 2050 for the population ages 65 and older show an even larger divide, according to Haub. Tanzania's older population will change only slightly, from 3 percent now to 4 percent in 2050. But Spain's population ages 65+ will nearly double, from 17 percent in 2012 to 33 percent in 2050. The elderly share of Tanzania's population "will barely grow while in Spain one-third of the population will be elderly by 2050," he pointed out.

Differences in each country's age structure and fertility level have enormous implications for each country's future size. Tanzania has 1.5 million more births each year than Spain. By 2050, Tanzania's population is projected to nearly triple to reach 138 million, while "any growth in Spain is likely to come mainly from immigration," he said. In Europe births and deaths are "just about in balance," while in less developed countries births far outnumber deaths, reflecting a large share of young people in their childbearing years and much higher birth rates.

The U.S. population also is beginning to age rapidly and is growing more slowly. "The U.S. non-Hispanic white population looks like a European country, with dwindling numbers of youth," said Haub. With a higher birth rate and more youth, Hispanics and other minorities "keep the U.S. population young." Women in the United States now average 1.9 children, down from 2.1 several years ago. In Haub's opinion this decline reflects the recent economic recession and "will probably turn around when the economy improves."

Chronic Diseases Like Cancer and Diabetes Taking Growing Toll Worldwide

PRB's 2012 World Population Data Sheet has a special focus on chronic or noncommunicable diseases (NCDs), such as cardiovascular disease, cancers, diabetes, and respiratory diseases. While developing countries are typically still battling infectious diseases like tuberculosis, HIV/AIDS, and malaria, NCDs are now the leading cause of death in all world regions except sub-Saharan Africa, reported Wendy Baldwin, PRB's president and CEO.

While the number of people suffering and dying from NCDs will continue to increase around the world over the next several decades, the greatest increases are expected in low-income countries. Even in sub-Saharan Africa, NCDs will account for almost half of all deaths by 2030.

Because NCDs in developing countries "strike earlier in life than in wealthier countries," they may affect breadwinners, putting "a greater burden on families," said Baldwin. In South Asia the mean age of first heart attack is six years earlier than the rest of the world. The prolonged nature of NCD-related illnesses also "creates massive burdens on health care systems," she said.

Four behavioral risk factors account for most NCDs: tobacco use, unhealthy diet, insufficient physical activity, and harmful use of alcohol. These behaviors "are often exacerbated by urban living and the developing world is the urbanizing world," noted Baldwin.

But these are behaviors that can be changed. "There are many examples of effective programs but programs need to be tailored to specific settings," she said. Targeting youth and adolescence when behaviors such as alcohol and tobacco use begin is one of the most cost-effective approaches and "reaps benefits for decades." In Baldwin's view, it is "preferable to support positive behaviors early in life rather than wait a few decades and try to change entrenched habits."

From 7 Billion to 8 Billion in 12 Years?

World population reached 7 billion in 2011, and now totals almost 7.1 billion. The new data sheet clearly illustrates a continuing rapid expansion in world population. Sub-Saharan Africa will grow at the fastest rate and is projected to add a "truly astounding" 1.2 billion people by 2050, according to Haub. With a current population of 4.3 billion, Asia will likely experience a much smaller proportional increase than Africa, but will still add about 1 billion people by 2050—determined in large part by what happens in China and India. Latin America and the Caribbean is the developing region with the smallest proportional growth expected by 2050, from 599 million today to 740 million, largely due to fertility declines in several of its largest countries such as Brazil and Mexico.

When will world population reach 8 billion? "Quite likely within 12 years" of reaching 7 billion, said Haub. The timing depends on what happens to birth rates in developing countries and the availability of family planning, he explained. While there is a strong desire for more than two children in many countries, there are many women—particularly women in the poorest share of their country's population—who want to limit or space their children but do not have access to family planning.