The greatest challenge today is to meet the needs of current and future generations, of a large and growing world population, without imposing catastrophic pressures on the natural environment. Meeting this challenge depends on decisive policy changes in three areas: more inclusive economic growth, greener economic growth, and population policies. This article focuses on efforts to address and harness demographic changes for sustainable development, which are largely outside the purview of the current debate. Efforts to this end must be based on the recognition that demographic changes are the cumulative result of individual choices and opportunities, and that demographic changes are best addressed through policies that enlarge these choices and opportunities, with a focus on ensuring unrestricted and universal access to sexual and reproductive health information and services, empowering women to fully participate in social, economic and political life, and investing in the education of the younger generation beyond the primary level. The article provides a strong argument for why the Programme of Action that was agreed at the International Conference on Population and Development (ICPD) 20 years ago continues to hold important implications and lessons for the formulation of the post-2015 development agenda, which is expected to supersede the Millennium Development Goals (MDGs).

In preparing for the RIO+20 Earth Summit, the world community must acknowledge that population trends interact strongly with economic development and environmental change at local and global levels. The International Institute for Applied Systems Analysis (IIASA) recently convened leading experts to consider how demographic factors promote or impede sustainable development. The panel concluded that human beings—their numbers, distribution, and characteristics—are at the center of concern for sustainable development ([ 1 ][1]). The evidence is clear that demographic differences fundamentally affect people's contribution to environmental burdens, their ability to participate in sustainable development, and their adaptability to a changing environment. The developmental challenges are by far the most significant where population growth and poverty are the highest, education is the lowest, and vulnerabilities to environmental change are the greatest. Within families, women and children are most vulnerable. As members of this panel, we put forward five action implications: (i) Recognize that the numbers, characteristics, and behaviors of people are at the heart of sustainable development challenges and of their solutions. (ii) Identify subpopulations that contribute most to environmental degradation and those that are most vulnerable to its consequences. In poor countries especially, these subpopulations are readily identifiable according to age, gender, level of education, place of residence, and standard of living. (iii) Devise sustainable development policies to treat these subpopulations differently and appropriately, according to their demographic and behavioral characteristics. (iv) Facilitate the inevitable trend of increasing urbanization in ways that ensure that environmental hazards and vulnerabilities are under control. (v) Invest in human capital—people's education and health, including reproductive health—to slow population growth, accelerate the transition to green technologies, and improve people's adaptive capacity to environmental change. 1. [↵][2] IIASA, World Population Program, Demographic Challenges for Sustainable Development ([www.iiasa.ac.at/Research/POP/Laxenburg%20Declaration%20on%20Population%20and%20Development.html][3]). [1]: #ref-1 [2]: #xref-ref-1-1 View reference 1 in text [3]: http://www.iiasa.ac.at/Research/POP/Laxenburg%20Declaration%20on%20Population%20and%20Development.html

Population aging worries many. Will population aging negatively affect economic output and lead to deflation? Can countries afford to cater for older populations? Can they prevent old-age poverty? Can they pay adequate pensions? Can they address the challenge of population aging by postponing the retirement age? Should they seek to counteract population aging through accelerated immigration and/or should they focus on maintaining fertility rates above replacement levels? Although some answers to these questions are context-specific, this paper argues that the threat of population aging is overstated. It is hyped by media and too often based on partial analysis. A macroeconomic analysis provides a more adequate and less threatening picture of population aging than the household-focused analysis that underlies most studies on this subject matter. The developed economies that already have a large share of older persons are well positioned to shoulder the economic implications of further population aging, and rapidly developing economies, which see an accelerated rate of population aging, are too. Many countries have the economic conditions to address population aging, but many lack the necessary resolve to implement the required policies. Popular policy responses to population aging are building up to a major wave of income redistribution, following the globalization of finance and the current responses to the global economic crisis.