As the world continues to add close to 80 million people each year, high population growth is running up against the limits of our finite planet, threatening global economic and political stability. To stay within the bounds of the earth's natural resources, the world's population will have to stabilize.
The United Nations' recently revised "medium" projection (http://esa.un.org/unpd/wpp/index.htm) shows world population exceeding 9 billion by 2045. In the "high" projection, which assumes high levels of fertility, world population would top 10 billion by the same year. But spreading hunger and poverty, along with the conflict and disease that come with them, could forcibly curtail growth before we reach 9 billion. Alternatively, the "low" projection suggests it is possible for world population to peak at just over 8 billion around 2045 if we voluntarily make rapid reductions in family size.