Zero population growth

Zero population growth, sometimes abbreviated ZPG, is a condition of demographic balance where the number of people in a specified population neither grows nor declines; that is, the number of births plus in-migrants equals the number of deaths plus out-migrants. The Zero Population Growth organization, founded by biologist Paul R. Ehrlich, induced a prominent political movement since the 1960s, aiming to reach zero population growth.

The movement considers zero population growth to be an objective towards which countries and the whole world should strive in the interests of accomplishing long-term optimal standards and conditions of living. It faces substantial support as well as criticism, involving different groups of people in society.