(February 2009) "The World in 2050: A Scientific Investigation of the Impact of Global Population Changes on a Divided Planet" was held in Berkeley, Calif., on Jan. 23 and 24, 2009. The forum focused on the impact of population growth and population decline on economic and social development, on resources, and on broad national and international issues such as energy use, environmental degradation, and conflict. The goal of the forum is to develop the best possible population-related policies and programs that will foster the welfare of the human and natural world.

The forum was sponsored by the Fred H. Bixby Foundation, and coordinated by the Bixby Center for Population, Health and Sustainability, University of California, Berkeley; Bixby Program in Population and Reproductive Health, University of California, Los Angeles; and the Bixby Center for Global Reproductive Health, University of California, San Francisco.

Each day's presentations have been webcast; presenters' PowerPoints are synchronized with their presentations.

Jan. 23, 2009: Day 1 Presentations and Discussions

View webcast of this session (Time: 1 hr 52 min):

Human Population Growth and Demographic Transition (session description below)
Presentation by: John Bongaarts, Population Council, "Human Population Growth"
Discussant: Eliya Zulu, African Population and Health Research Center

Patterns of Stall in Fertility Decline and Their Determinants in Eastern Africa (session description)
Presentation by: Alex Ezeh, African Population and Health Research Center, "Stalled Fertility Decline in Eastern Africa: Evidence and Implications"
Discussant: Eliya Zulu, African Population and Health Research Center

View webcast of this session (Time: 41 min): Declining Populations (session description below)

Presentation by: Nicholas Eberstadt, American Enterprise Institute, "Population Decline"
Discussant: Hania Zlotnik, United Nations Population Division, "Declining Populations"

View webcast of this session (Time: 1 hr 28 min): Population, Poverty, and Economic Development (session description below)

Presentation by: Steven Sinding, Guttmacher Institute, "Population, Poverty, and Economic Development"
Presentation by: Wolfgang Lutz, IIASA, "Sola Schola et Sanitate: Human Capital as the Root Cause and Priority for International Development?"
Discussant: David Canning, Harvard University

View webcast of this session (Time: 59 min): Population and Climate Change (session description below)

Presentation by: John Harte, University of California, Berkeley, "Global Warming and the World in 2050"
Discussant: Hilary Godwin, University of California, Los Angeles

View webcast of this session (Time: 1 hr 20 min): General Discussion
Presentation by: Linna Hao, National Population and Family Planning Commission of China, "Comprehensively Addressing Population Issues for the Sustainable Development of the Society and Economy"

Human Population Growth and Demographic Transition
The world and most regions and countries are experiencing unprecedentedly rapid demographic change. The most obvious example of this change is the huge expansion of human numbers: 4 billion have been added since 1950. Projections for the next half century expect a highly divergent world, with stagnation or potential decline in parts of the developed world and continued rapid growth in the least developed regions. Other demo­graphic processes are also undergoing extraordinary change: women's fertility has dropped rapidly and life expectancy has risen to new highs. Past trends in fertility and mortality have led to very young populations in high fertility countries in the developing world and to increasingly older populations in the developed world. Contemporary societies are now at very different stages of their demographic transitions. This paper summarizes key trends in population size, fertility and mortality and age structures during these transitions. The focus is on the century from 1950 to 2050, which covers the period of most rapid global demographic transformation.

Patterns of Stall in Fertility Decline and their Determinants in Eastern Africa
We use data from the Demographic and Health Surveys to examine the patterns of stall in fertility decline in four Eastern African countries. Contrary to patterns of fertility transition in Africa that cut across various socioeconomic and geographic groups within countries, we find strong selectivity of fertility stall across different groups and regions in all four countries. In both Kenya and Tanzania where fertility decline has stalled at the national level, it continued to decline among most educated women and those in some regions. While fertility has remained at pretransition level in Uganda over the past 20 years, there are signs of decline with specific groups of women (especially the most educated, urban, and those in the eastern region) taking the lead. For Zimbabwe, although fertility has continued to decline at the national level, stall is observed among women with less than secondary education and those in some regions. We link these intra-country variations to differential changes in socioeconomic variables, family planning, program environment, and reproductive behavior models. The results suggest that declines in contraceptive use, increases in unmet need for family planning, increasing preferences for larger families, and increases in adolescent fertility were consistently associated with stalls in sub-group fertility across all four countries. These results are consistent with models that emphasize the role of decline in national and international commitment to family planning programs in the premature stall in African fertility transition.

Declining Populations: Population, Poverty, and Economic Development
The upper and lower bounds of population projections and changing age structure for the low fertility regions of Europe, former Soviet Union, and East Asia can be made to 2050 with some assurance. Legal and illegal migration from other regions will continue, although the rate is more difficult to guess. It is possible to forecast many but not all of the impacts of an aging population. The population of Europe will decline by between 3 percent (23 million) and 22 percent (163 million) by 2050. Japan's population will also decline by 20 percent (25 million) by 2050. An aging population has an impact on the tax base and the structure of the work force.

Population, Poverty, and Economic Development
Economists, demographers, and other social scientists have long debated the relationship between demographic change and economic outcomes. In recent years, general agreement has emerged to the effect that improving economic conditions for individuals generally leads to lower birth rates. But there is much less agreement about the proposition that lower birth rates contribute to economic development and help individuals and families to escape from poverty. The paper examines recent evidence on this aspect of the debate, concludes that the burden of evidence now increasingly supports a positive conclusion, examines recent trends in demographic change and economic development, and argues that the countries representing the last development frontier, those of sub-Saharan Africa, would be well advised to incorporate policies and programs to reduce high fertility in their economic development strategies.

Sola Schola et Sanitate: Human Capital as the Root Cause and Priority for International Development?
This paper summarizes new scientific evidence supporting the hypothesis that among the many factors contributing to international development, the combination of education and health stands out as a root cause on which other dimensions of development depend. Much of this recent analysis is based on new reconstructions and projections of populations by age, sex, and four levels of educational attainment for more than 120 countries using the demographic method of multistate population dynamics. It also refers to a series of systems analytical population-development-environment (PDE) case studies that comprehensively assess the role of population and education factors relative to other factors in the struggle for sustainable development. The paper also claims that most concerns about the consequences of population trends are in fact concerns about human capital, and that only by adding the "quality" dimension of education to the traditionally narrow focus on size and age structure can some of the long-standing population controversies be resolved.

Population and Climate Change
Of the many threats to our planet, climate change ranks among the most severe, for it has the capacity to undermine the life support system upon which human well-being is dependent. A growing human population has been a major contributor to the problem, both because it has resulted in growing greenhouse gas emissions from energy consumption and food production, and because it creates barriers to solutions. These barriers arise because in an increasingly crowded world, issues of war, hunger, disease, poverty, and injustice become paramount, taking precedence over efforts to mitigate climate change despite the fact that climate change will hugely exacerbate these more tangible threats.