Perhaps what the world needs today is not ZPG, but ZPIG, zero population-impact growth. For it is not just the number of people that is important, but how much they produce, consume, and waste. Affluent nations have an impact on the environment very disproportionate to their populations. It has been estimated that an average American has 50 times the environmental impact of an average person in poor countries, in terms of resources used and pollution caused. It should be noted that wastefulness, injustice, heavy military spending, and inequitable distribution of resources are also responsible for current world problems.
Most people connect the widespread hunger in the world today to overpopulation.
Yet, several studies have indicated that there is currently enough food in the world to feed all the world's people adequately, and the problem lies in waste and inequitable distribution. For example, in the U. S. over 70 percent of the grain produced goes to feed the 9 billion animals destined for slaughter each year, and two-thirds of our exports are used for animal feed, while at least a billion of the world's people lack enough food. Poverty, injustice, and inequality also contribute to continued population growth. The poorer countries do not provide unemployment benefits, sick leave, or retirement pensions. Hence, children are depended upon as the only form of security in periods of unemployment, illness, and old age.