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.

Definition The growth rate of a human population in a given year equals the number of births minus the number of deaths plus immigration minus emigration expressed as a percentage of the population at the beginning of the given year. For example, suppose a country begins a year with one million people and during the year experiences one hundred thousand births, eighty thousand deaths, one thousand immigrants and two hundred emigrants. Change in population = 100,000 – 80,000 +1,000 – 200 = 20,800 Population growth rate = (20,800 ÷ 1,000,000) x 100% = 2.1% Zero population growth for a country occurs when the sum of these four numbers – births minus deaths plus immigration minus emigration - is zero. To illustrate, suppose a country begins the year with one million people and during the year experiences 85,000 births, 86,000 deaths, 1,500 immigrants and 500 emigrants. Change in population = 85,000 – 86,000 + 1,500 – 500 = 0 Population growth rate = (0 ÷ 1,000,000) x 100% = 0% For the planet Earth as a whole, zero population growth occurs when the number of births equals the number of deaths.

History

Coining the term The American sociologist and demographer Kingsley Davis is credited for coining the term "zero population growth" (ZPG) in 1967 by discussing the negative consequences of an uncontrollably growing population and suggesting a population growth below zero as the solution across nations. Although the term "zero population growth" was first introduced by Davis, the concept of a "stationary population", which means a population that is stable and unchanging in size, was referred to earlier by George J. Stolnitz in his "A Century of International Mortality Trends: I". A stable population requires a constant fertility and mortality rates with no immigration. When the constant rate of population increase equals zero, the stable population becomes stationary. Stolnitz stated that this concept dated back at least to 1693, when it showed up in Edmond Halley's recording of Breslau's population, the first life table on demographic data. A mathematical description was given by James Mirrlees.

Fear of overpopulation World population grew slowly for most of human history. The net population in the past 200 years is seven times the growth in the rest of human history. Population growth first started to accelerate after the Agricultural Revolution in 1650, and it caused people to first concern about overpopulation because they feared the growth of population would eventually outrun the growth in food production. Similar concerns reemerged after WWII because some people believed that the war was triggered by the competition over scarce resources among the Axis nations. By the late 1960s, environmental exploitation and famine in Africa enhanced the concern of overpopulation. The idea of zero population growth emerged as a solution to mitigate the ongoing problems.

Zero Population Growth organization (ZPGO) In the post-war period, the Western world experienced a baby boom (1945–1968 period) that statistically links to the increased female employment during wartime. Responding to the postwar population growth, ZPG became a prominent political movement in the U.S. and parts of Europe, with strong links to environmentalism and feminism in the late 1960s. Biologists Paul R. Ehrlich accused overpopulation as the single cause to environmental issues occurred during the 1960s in his famous work The Population Bomb published in 1968. The same year, Ehrlich, along with entomologist Charles Remington and lawyer Richard Bowers, founded the Zero Population Growth Organization in Connecticut, with a goal to reduce family sizes among Americans. The organization quickly expanded, attracting membership of 36,000 by May, 1971. In 1970, ZPGO set its lobbying office in Washington, D.C. Among the ZPGO activists, Yale University was a stronghold. Yale University and many other ZPGO members believed that the non-stopping growing population causes many environmental and societal problems, as well as threatens the individual values and privacy.

Controversy Upon the establishment of the ZPGO, it faced a great amount of support as well as criticisms. The debate over its purpose and mission involved the possibility of zero population growth, its impact on economy as well as on cultural and personal values.

Possibility and necessity There were several criticisms against the Zero Population Growth movement. ZPGO activists were accused for turning against the science of demographic growth and asking for an immediate drop in fertility. Critics also said that the activists are recommending something inevitable in the future, questioning the necessity of their efforts. American demographer and sociologist Judith Blake, a member of the ZPG movement, responded by accepting that ZPG is the only possibility in the future. Nevertheless, if people passively waited for it to happen, ZPG would eventually be reached through high mortality rather than low fertility.

… excerpt ends here. Continue reading the full article.