11/3/2023 0 Comments Demographic trends examplesThe entire transition typically takes more than a century to complete and ends with a much larger population size. In the second phase, the growth rate declines (but remains positive) due to a decline in the birth rate. During the first phase, the population growth rate rises as the death rate declines while the birth rate remains high. During the intervening transition period, rapid demographic change occurs, characterized by two distinct phases. Population growth is again near zero after the completion of the transition as birth and death rates both reach low levels in the most developed societies. Before the transition's onset, population growth (which equals the difference between the birth and death rate in the absence of migration) is near zero as high death rates more or less offset the high birth rates typical of agrarian societies before the industrial revolution. This transition usually accompanies the development process that transforms an agricultural society into an industrial one. Over the course of this transition, declines in birth rates followed by declines in death rates bring about an era of rapid population growth. The recent period of very rapid demographic change in most countries around the world is characteristic of the central phases of a secular process called the demographic transition. Around 2070, the world's population will be 10 times larger than in 1800. This population expansion is expected to continue for several more decades before peaking near 10 billion later in the twenty-first century. As a result, world population more than doubled to 6.5 billion in 2005 (United Nations 1962, 1973, 2007). During the second half of the twentieth century, however, growth rates accelerated to historically unprecedented levels. The modern expansion of human numbers started then, rising at a slow but more steady pace over the next 150 years to 2.5 billion in 1950. The focus is on the century from 1950 to 2050, which covers the period of most rapid global demographic transformation.Īfter centuries of very slow and uneven growth, the world population reached one billion in 1800. This paper summarizes key trends in population size, fertility and mortality, and age structures during these transitions. Contemporary societies are now at very different stages of their demographic transitions. Past trends in fertility and mortality have led to very young populations in high fertility countries in the developing world and to increasingly older populations in the developed world. Other demographic processes are also undergoing extraordinary change: women's fertility has dropped rapidly and life expectancy has risen to new highs. Projections for the next half century expect a highly divergent world, with stagnation or potential decline in parts of the developed world and continued rapid growth in the least developed regions. The most obvious example of this change is the huge expansion of human numbers: four billion have been added since 1950. The world and most regions and countries are experiencing unprecedentedly rapid demographic change.
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