Approximately 7.7 billion men, women and children now populate the world. This number has increased by 4 billion people in the last 50 years – more than doubling since 1970. Population growth rates have since been declining, though absolute population figures have continued to increase. In the next half century, however, a scenario exists where world population may decline.

If population growth trends continue as in the past, there would be more than 15 billion earthlings by 2070, fifty years from now. In reality, there will not be that many people in the future because the population growth rate has been slowing considerably since the early 1960’s. For example, between 1960 and 1970, world population increased by 22 percent, while the growth rate between 2010 and 2020 is projected to be below 9 percent. According to the United Nations and other forecasters, the decennial growth rate is projected to continue to decline in subsequent decades.

Discerning and projecting population trends is a large and vital exercise that occurs at every level of government and business on a constant basis. Every entity from the United Nations to national governments, state and provincial governments, municipalities and school districts, all track population trends.

Population growth has been ever upward in world history, and certainly in recent decades. This has led to an environmental cottage industry to warn of the catastrophic consequences of this upward trend.

One of the most famous examples of population doomsday scenarios was the 1968 book The Population Bomb by Paul Ehrlich and Anne Ehrlich. Published during the rapid population growth rate in the 1960’s, the Ehrlichs predicted the result would be “hundreds of millions of people will starve to death” in the 1970’s since food production would not keep pace.

Turns out, this famine did not occur.

The Ehrlichs famously colossal miscalculation has not prevented them and many others from similarly absurd and ongoing predictions on future population and its effects on the environment from the planet supposedly having too many people. Extremist environmental groups have long viewed “population growth as causing environmental problems.” People are seen as a zero-sum detriment to the health of the earth itself. More people exhaling carbon dioxide, eating food, drinking water or cutting down trees is a bad thing, and so forth.

Overlooked in such ongoing doomsday predictions is that technology doesn’t stand still. Advances in agriculture and food production alone have kept a much larger world population from starvation. In fact, as the global population has increased, the world’s poverty rate has sharply fallen in the last quarter century, from more than 2 billion estimated to be in “extreme poverty” in 1990 to about 650 million today.

If UN predictions on global population growth play out, there will be approximately 8.6 billion people by 2030; 9.8 billion by 2050; and more than 11 billion by the turn of the century in 2100.

Then again, maybe not. Population growth trends have been slowing to the point such that an increasing concern is no longer overpopulation, but world population decline.

A recently published book, entitled Empty Planet: The Shock of Population Decline by social scientist Darrell Bricker and journalist John Ibbitson, makes a serious case study that in approximately 30 years, world population will peak, then decline continually afterwards. The authors point out, for example, that fertility rates are declining more sharply than conventional forecasts by the United Nations. A key reason for this is the level of improvement in female education worldwide, which leads to childbearing later in life, and having fewer children.

Interestingly, Messrs. Bricker and Ibbitson view the U.N.’s population forecasts as way out of step with existing data from many countries – not unlike the U.N.’s climate change predictions, in my view. In contrast to the U.N.’s projections, the book cites Austrian demographer Wolfgang Lutz who predicts world population by 2100 will be somewhere between 8 and 9 billion. This is only modestly higher than the present day, but would represent a decline from mid-century and as much as 3 billion below U.N. estimates.

Present-day evidence of population decline is real. As population trends have now shown an increasing slowdown in growth rates, several countries already are experiencing declines, including some nations in Europe and southern Asia, as well as Japan and Russia.

If population declines become widespread, large economic and social disruptions are likely, including the growing cost of caring for aging populations, and worker shortages to sustain economic growth and finance the needs of the elderly.

The long-standing cottage industry of over-population and its threats to the environment will not go away quickly or easily, but may soon be dwarfed by a growing reality of population decline. That will bring new challenges and a new set of ideas to encourage population stability and growth more for economic, rather than environmental concerns.