World population growth and the role of annual energy use per capita.

In the context of ongoing world population growth, no permanent growth in materials consumption can be sustained into the future. A sustainable future requires that the world's population stabilize. The author considers the possible coupling of the annual energy use per capita and the population growth rate for each region, and the consequences of such a connection if the world's population is to stabilize. Energy is used as a factor because it is a proactive agent in facilitating increases in the standard of living and changes in the social conditions thought to influence the fertility rate. Historical trends and near-term projections for energy use and population growth rate are used to indicate a possible future path for developing regions. Improvements in the efficiency of energy use and modest cultural changes are used in an example projection of coupled energy use and population growth. For each decade, the incremental increase in annual commercial energy use per capita and a corresponding decrease in population growth rate are chosen to continue the historical trends for developing regions of the world. This approach results in population changes which closely follow the projections of the World Bank for the period up to 2150. World energy use is projected to increase from about 9000 million tons of oil equivalent (Mtoe) today to 15,000-21,000 Mtoe/a by the time the world's population has risen from 6 billion to about 12 billion in the 22nd century. The energy demands of each developing region are compared with potential, indigenous energy sources to determine whether each developing region may be able to cope with its increased energy demand without massive energy imports. The availability of readily moveable, cheap fuels will help the developing world make the transition to a more stable population with a decent standard of living.