Five experts weigh in on today's population challenges

The Earth's human population is continuing to rise. The U.N. projects we will reach 7 billion people on October 31, 2011 and surpass 9 billion by 2050. Much of this growth will be uneven, however, with some nations having either a stable or shrinking population while other nations are expected to triple in size. Most of this rapid growth is in the poorer regions of the globe, which will likely increase the existing disparities (education, health care, and access to food, for example) between developed and undeveloped nations.

Somalia is facing a famine that affects 3.7 million people, according to the U.N. World Food Program. Some estimate that 2,500 people could die, per day, in August. Widespread famine has become rare in recent decades, this is the first official famine the U.N. has declared since 1984. But drought, war, political strife and local crop failure still can disrupt the global movement of food enough that thousands can go hungry, while others throw away food that rots uneaten.

AAAS MemberCentral asked five population experts about the effects of population growth and what they think we should do to provide a promising future for everyone on the planet.

AAASMC: Many link female education and family planning. What other effects can better education in the developing world have on the global population?
David Bloom, Ph.D. Clarence James Gamble Professor of Economics and Demography, Harvard School of Public Health: More and better education has myriad and potentially transformational effects on global population, generally slowing its growth and increasing its concentration in urban areas.

A first set of effects operates through fertility preferences and their expression. Increased schooling is powerfully associated with empowerment and with a willingness to depart from traditional practices. This is especially true among educated women, whose sense of self, autonomy, and voice are magnified. This tends to result in lower fertility and increased labor market opportunities, which spurs greater financial independence, and further empowers women — leading to even lower fertility.

A second set of effects operates through infant and child mortality rates, which tend to be diminished as education increases (especially for women). This leads to a boost in population growth in the short run, but a decline in the long run as couples respond to higher child survival by adjusting their fertility downward.

A final set of effects operates through the positive effect of education on the propensity to migrate from rural to urban areas. This occurs because the potential economic benefits of education are greater in cities than in rural areas. Once people move to cities, the higher cost of raising children tends to lower fertility rates.

AAASMC: Some countries, like Niger and Burkina Faso, could triple their populations in the next 50 years. What effects will these massive numbers of youth have on the regional and global community?
Wendy Baldwin, Ph.D. President and CEO of the Population Reference Bureau: Niger and Burkina Faso share some unenviable features — very high fertility (7 children on average in Niger, 5.8 in Burkina), low educational attainment, and lagging economic development. Ideally, their growing populations of young people would contribute to economic growth and be able to form stable, healthy families.

There is no simple path forward, but let's start with education and a requirement that children be in school, including young girls. Schooling increases their skills and reduces their role as "cheap labor" on farms or in towns. Increased schooling is an important path to supporting girls and young women to develop multiple ways that they could contribute to their society.

Schooling is a great alternative to early marriage and allows a girl time to mature physically, develop social and economic skills, and help her become more fully engaged in her community. Health services can help alter this path by ensuring that there is real access to modern contraceptives and appropriate care so that when women are pregnant they are not putting their lives in jeopardy.

AAASMC: What new health problems might doctors in 2050 be dealing with?
Eileen Crimmins, Ph.D. AARP Professor of Gerontology, Davis School of Gerontology, University of Southern California: The aging of the world population is the most predictable demographic trend of the next few decades. Population aging is inevitably accompanied by increasing disability — both mental and physical — and multiple chronic conditions. While delay to later ages of the onset of these problems is possible in the future, it seems likely that many years of life will require accommodation to, management of, and treatment of these complex conditions. Current health care systems are not well organized to deal with these problems that will become increasingly more important parts of our individual lives and place increasing demands on the social fabric of our societies.

AAASMC: The populations of some regions appear stable, while others are tripling. How can we mitigate this disparity and how might it affect the world in 2050 if this disparity in growth continues as predicted?
John Bongaarts, Ph.D. Vice President and Distinguished Scholar, Population Council: The most direct and humane way to address very rapid growth in poor countries is to help women reduce unplanned pregnancies. Each year about 184 million pregnancies occur in the developing world and about forty percent of these are unintended. Countries that have implemented voluntary family planning programs to provide information about and access to contraceptives, have greatly benefitted.

The United Nations estimates that "for every dollar spent in family planning, between two and six dollars can be saved in interventions aimed at achieving other development goals." Moreover, eliminating unplanned pregnancies could prevent a third of maternal deaths. Family planning should be restored to the high priority it enjoyed three decades ago. It should be seen not only in terms of its health and rights benefits but also as a critical and cost-effective investment in quality of life, alleviation of poverty, equity, and economic development.

AAASMC: Some claim the Malthusian crisis will never come. What do you think? And, if you think it will still happen, what do you think is the number one thing we can do to stop or forestall it?
William Butz, Senior Research Scholar, International Institute for Applied Systems Analysis and Director of Coordination and Outreach, Wittgenstein Centre for Demography and Global Human Capital: I don't know about "never," but not within my children's lifetimes. It's 213 years now since Reverend Malthus foresaw that population would grow "geometrically\ while food would grow "arithmetically," leading to "misery and vice" in order to forestall starvation. There are many more of us now, but all, save the poorest, are better fed, healthier, and longer lived than the mass of humanity in Malthus' day. In the last half-century, schooling, life expectancy, and contraceptive use have increased just about everywhere, even in sub-Saharan Africa, the only region where agricultural productivity hasn't also risen.

Meanwhile, although world population continues to increase, it does so ever more slowly because fertility rates have fallen in almost every country. Malthus underestimated the human proclivity for ingenuity, and overestimated our appetite for reproduction. The distant future might be different and there are concerns, particularly on the environmental front.

But to predict that 50 years of experience will do a 180 in this century requires mighty strong evidence. We can insure against this unlikely possibility: Keep investing in schooling, broadly shared economic development, and contraceptive availability, and raise the incentives to invent and use agricultural, medical, and green technologies.

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