ABSTRACT
Phenomenally, the term demographic transition has over time been perceived as an intellectual tool for policy and decision-making, although fluid and elusive the concept and theories of demographic transition has been a resource for policy makers over the years. From the late 18th century, the death rate dropped. With the development of new technologies in agriculture and production, as well as health and hygiene, more people have become healthy, increasing their average life expectancy and creating new trajectories for population growth. This sudden change has long created a shift in what people “understand” to be, the correlation between birth rate and mortality. Over the past 300 years, the population in most countries have continued to develop due to the relationship between birth and mortality in these countries.
This global phenomenon of observation and recording produces a pattern of demographic transition models that helps to explain and understand demographic changes. Using the demographic transition model, demographers can better understand the current population growth of a country based on its position between the four major stages and then transmit the data to address a country and its transnational economic and social policy. In the course of human history, there have been many people interested in the future of demographic characteristics and population growth. After analyzing the changes in the Western population over time, a pattern was found that shows that population growth is linked to the economic development of a country. It has been pointed out that in countries with high standard of living, 98population growth is slow and the population of countries with low living standards grows faster.
This finding leads to the concept of demographic transition, a series of stages in which a country has moved from nonindustrial to industrialized. The concept of “population change” involves four stages of population size and social behavioral change. As in the case of the United States, its history has undergone major demographic changes. Like many other developed countries in the world, traditional demographic changes related to declining mortality and declining fertility have also contributed to subsequent demographic changes. These changes include urban transformation, marital transition, family transformation, aging transformation, and ethnic transition. In these transformations, the most prominent at the beginning of the 21 century is the latter two: the aging transition and the racial and ethnic transition.
Pragmatically, if the number of baby boomers begins to reach 65 years between 2017 and 2031, the country will rapidly be aging. In addition, as the White population began to decline due to the low fertility and aging, the Hispanic population would dominate the national population because of its youthfulness. In fact, population projections show that the Latino population will double from 50.5 million in 2017 to 111.7 million by 2050, while the White population would decline from 196.8 billion to 186.3 million during this period. These major demographic transitions will have a significant impact on the demographic, social, and economic trends of the next few decades, which in many ways may lead to differences in experience between the United States and other developed countries. The discussions on the impact of these trends on the future of the United States have become a popular debate and lecture.
The world and most regions and countries at large are experiencing some unprecedented rapid population changes. The most obvious example of this change is the huge expansion of the number of manpower: since 1950, there has, been more than 40 billion growth. The forecast for the second half of the world is expected to develop rapidly in the developed countries, where parts of the region are stagnant or potentially declining and continuing to grow rapidly in the least developed regions. Other population movements have also changed dramatically: women’s fertility has fallen sharply and life expectancy has risen to new heights. Past fertility and mortality trends have led to high fertility in developing countries. The growing population in most developing countries and developed countries is very young. Contemporary societies are now in a different stage from the demographic transition. This chapter summarizes the major trends in population size, fertility, and 99mortality, and aging structure during transitional periods. The focus will be from 1950 to 2050 in a century, the world in its fastest population changing period.
