Population growth, age structure, and environmental impact

We develop and use a simulation model that considers sustainability on several levels by calculating production, consumption, investment, population growth/change, and environmental pollution less environmental quality upgrading investment. Our model allows us to consider population's impact on per capita consumption as well as the social interdependencies among populations, per capita consumption, and technology. Under certain population growth scenarios we find some countries ultimately consume less pollution, and less pollution is consumed on a system-wide basis. We arrive at this apparently counterintutive result because: (1) we explicitly model the decision to invest in environmental quality upgrading; and (2) we consider the impact of population age structure on investment, not only the impact of total population and population growth on total consumption.