The maximum "carrying capacity“ of the globe is estimated to be roughly 9 billion people, considering natural resources like fertile land and water. Thus, the worst-case-scenario would be a world population of 11 billion combined with increasing resource consumption. The best-case-scenario is a stabilized world population of less than 8 billion, combined with efficient technologies which are able to reduce the per capita consumption of land, water, energy and other resources. Only this provides a realistic chance for long term sustainable development.