Perspectives on International Trends and Dynamics in Population and Consumption

There are increasing concerns that global environmental limits may soon be met as a result of increasing numbers of people coupled with increasing consumption of resources. However, the current level and rates of growth in both consumption and population vary systematically among countries grouped according to income levels. Many high income countries have population growth rates at close to replacement levels, but their per capita consumption is consistently several times higher than low income countries. Low income countries need to grow out of poverty and have high population growth rates. Using current population structures for India and the USA in an age-structured demographic model, and simple projections of annual reductions in fertility or consumption per capita over the next 50 years, we show that while reductions in both consumption and fertility are necessary to stabilize impacts, there are short term gains from consumption reductions in high income countries such as the USA, and long term gains from early fertility reductions in growing economies such as India.