per year. During that period, population growth was governed by conditions now labeled the “Malthusian Trap”. After 1700, driven by increases in human productivity due to the Industrial Revolution, particularly the increase in agricultural productivity, population growth accelerated to around 0.6% per year, a rate that was over ten times the rate of population growth of the previous 12,000 years. This rapid increase in global population caused Malthus and others to raise the first concerns about overpopulation. After World War I birth rates in the United States and many European countries fell below replacement level. This prompted concern about population decline. The recovery of the birth rate in most western countries around 1940 that produced the "baby boom", with annual growth rates in the 1.0 – 1.5% range, and which peaked during the period 1962 -1968 at 2.1% per year, temporarily dispelled prior concerns about population decline, and the world was once again fearful of overpopulation. But after 1968 the global population growth rate started a long decline, and in the period 2022–2027 the UN estimates it to be about 0.9%, less than half of its peak during the period 1962 - 1968. Although still growing, the UN predicts that global population will level out around 2086, and some sources predict the start of a decline before then. The principal cause of this phenomenon is the abrupt decline in the global total fertility rate, from 5.3 in 1963 to 2.4 in 2019. The decline in the total fertility rate has occurred in every region of the world and has brought renewed concern from some for population decline. The era of rapid global population increase, and concomitant concern about a population explosion, has been short compared with the span of human history. It began roughly at the beginning of the industrial revolution and appears to be now drawing to a close. Possible consequences Predictions of the net economic (and other) effects from a slow and continuous population decline (e.g. due to low fertility rates) are mainly theoretical since such a phenomenon is a relatively new and unprecedented one. The results of many of these studies show that the estimated impact of population growth on economic growth is generally small and can be positive, negative, or nonexistent. A recent meta-study found no relationship between population growth and economic growth. Possible positive effects The effects of a declining population can be positive. The