Recent projections suggest the human population will peak at 9 billion by 2050 and then slowly decrease. Some countries already have a decreasing population, which brings different challenges to that of a rising population. Rates of change will vary by region and country. This result raises critical questions about Earth's sustainable human-carrying capacity. Estimating this capacity requires an interdisciplinary perspective to evaluate trade-offs between food production, energy use, natural resource conservation, environmental quality and consumption. Recent advances in geospatial analysis, remote sensing, and simulation modeling allow a new look at key questions: When will the human population peak and at what level? How fast will it decline? What is the impact of family planning programs in the past 50 years and what role will they play in the future? Can the projected increase in food demand be met without large-scale expansion of agriculture at the expense of natural ecosystems? How much land is required to maintain natural ecosystems as a carbon-rich and bio-diverse habitat for future generations? Discussion will take into account the need for humanity to flourish rather than merely survive. These issues will be addressed by distinguished scientists from the disciplines of demography, ecology, crop science, economics, and public policy.