ABSTRACT
No topic is more important for ecological sustainability than the expansion of human numbers. World population has been growing at a billion people every dozen years. This growth rate has been amazingly constant for the last half century (see Figure 32.1) and another billion are expected in the next dozen years (United Nations, 2011, 2013, 2015). Each new person needs somewhere to live, somewhere to grow food, somewhere to deposit their waste and pollutants, somewhere to have a job, and somewhere to get the energy and materials they need. All these somewheres are the environment. The enormous ecological footprint of a billion extra people every dozen years swamps the achievements of environmentalists (Wyman, 2013). In terms of global ecology, demography is destiny.
