A report on Population decline

Because all nations before the Industrial Revolution were caught in what is now labeled the "Malthusian Trap", improvements in standards of living could only be achieved by reductions in population growth through either increases in mortality rates (via wars, plagues, famines, etc) or reductions in birth rates.

Malthusianism is the idea that population growth is potentially exponential while the growth of the food supply or other resources is linear, which eventually reduces living standards to the point of triggering a population die off.

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 concept is often discussed in relation to other population concerns such as demographic push and depopulation, as well as in relation to resource depletion and the human impact on the environment.

It may feature deindustrialization, depopulation or deurbanization, economic restructuring, abandoned buildings or infrastructure, high local unemployment, increased poverty, fragmented families, low overall living standards or quality of life, political disenfranchisement, crime, elevated levels of pollution, and a desolate cityscape known as greyfield land or urban prairie.

During stage four there are both low birth rates and low death rates. Birth rates may drop to well below replacement level as has happened in countries like Germany, Italy, and Japan, leading to a shrinking population, a threat to many industries that rely on population growth. As the large group born during stage two ages, it creates an economic burden on the shrinking working population. Death rates may remain consistently low or increase slightly due to increases in lifestyle diseases due to low exercise levels and high obesity rates and an aging population in developed countries. By the late 20th century, birth rates and death rates in developed countries leveled off at lower rates.

Only a few countries have had, for the time being, sufficiently sustained sub-replacement fertility (sometimes combined with other population factors like higher emigration than immigration) to have population decline, such as Japan, Germany, Lithuania, and Ukraine.

Its characteristics are depopulation, economic restructuring, abandoned buildings, high local unemployment (and thus poverty), fragmented families, political disenfranchisement, crime, and a desolate, inhospitable city landscape.

The term "Rust" refers to the impact of deindustrialization, economic decline, population loss, and urban decay on these regions attributable to the shrinking of the once-powerful industrial sector especially including steelmaking, automobile manufacturing, and coal mining.

Since the late 1960s through the end of the 20th century, Flint has suffered from disinvestment, deindustrialization, depopulation, urban decay, as well as high rates of crime, unemployment and poverty.