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Overview If current trends continue, the demographic profile of the United States will change dramatically by the middle of this century, according to new population projections developed by the Pew Research Center.
Figure 1 Of the million people An overview of population growth in to the population during this period due to the effect of new immigration, 67 million will be the immigrants themselves, 47 million will be their children and 3 million will be their grandchildren.
Immigration is projected to be the key driver of national population growth in the coming half century, but it is important to note that possible future changes in immigration policy or other events could substantially alter the projected totals.
These projections are based on trends over the past half century, during which immigration, both authorized and unauthorized, has played an escalating role in U.
From tonew immigrants and their U. The contribution of new immigration to population change was derived by comparing our main projection with an alternative projection that assumes no new immigrants arrive after The heightening role of immigration contrasts with a decrease in fertility in recent decades.
The average number of births per woman has declined markedly since the late s, from more than 3. Also, a smaller proportion of women are of childbearing age now, compared with earlier decades.
These two changes have made immigration a more prominent factor in population growth. All population projections have built in uncertainties, especially for years further in the future, because they are based on assumptions about future behavior.
In addition, these uncertainties can multiply because key aspects of population change are often interrelated—for example, a decline in immigration could also lead to a decline in the birthrate because immigrants tend to have larger families than do native born residents.
The Center has developed three different population projections forbut the body of this report presents findings from the main projection figures from projections based on lower or higher immigration levels are set forth in a section that starts on page These projections consolidate and build upon past trends, present conditions, and factors affecting future behavior.
None of the projections should be treated as predictions. Even given these caveats, however, population projections are an important analytical tool for planners. Demographic change has major implications for government spending in key areas such as schools, health programs, community services, infrastructure and Social Security.
Projections also provide business with a basis upon which to make judgments about future markets. And they are of increasing interest because of the role that population may play in climate change and other environmental concerns. The models and assumptions are disaggregated by race and by Hispanic origin, as are many projection models e.
When incorporating birth estimates into the projections, the Center has assumed that the overall fertility rate will remain near the level it has been for the past three decades, with differing rates by race and ethnicity Appendix, Figure A2.
Birthrates are assumed to be well above average for immigrants, slightly above average overall for the second generation U. Census Bureau, ; Social Security Administration, As for death rates, life expectancy is assumed to improve somewhat for all groups throughout the period covered by these projections.
Immigration to the United States has risen rapidly and steadily for decades as a result of increasing globalization and population movements, changes in U.
Not only have the numbers of new U. In the face of these strong and persistent trends, most U. As a result, official projections over the last several decades have consistently underestimated actual population growth. The Pew Research Center projections have assumed that the annual immigration level, now about 1.
Figure 3 This rate of growth is in line with, but somewhat slower than, the growth trends of the last several decades. These immigration levels are slightly higher than those projected by either the Census Bureau or the Social Security Trustees in the short run and substantially higher toward the end of the projection horizon.
The rate is slightly below the rate for the first half of this decade and equal to the average for the last 35 years.
Figure 4 The decades-long pattern of steady increases has been interrupted recently by year-to-year variation, including a spike ina sharp decline in Passel and Suro,followed by a return to the long-term average in the last several years.
The relatively steady growth of the last 70 years contrasts with substantial fluctuations that occurred in the 19th and early 20th centuries. The projections also assume that several hundred thousand foreign-born residents will leave each year, which is in keeping with trends of the past several decades.
The issue of illegal immigration has become highly contentious in recent years. Last summer, Congress tried but failed to pass a comprehensive reform bill, and the debate over how to change immigration policies has become a major topic of the current presidential campaign. It is possible that a future Congress will enact laws that would sharply cut immigration flows.
This has happened before. The Immigration Act of along with an economic depression and a world war drastically reduced immigrants as a share of the U.China's one-child policy was established by Chinese leader Deng Xiaoping in to restrict communist China's population growth and limited couples to having only one child.
Although designated a "temporary measure," it remained in effect for more than 35 years. Fines, pressures to abort a. An overview of the UK population, how it’s changed, what has caused it to change and how it is projected to change in the future. The UK population is also compared with other European countries.
Following the relatively high population growth in the UK population during the “baby boom” of the s, growth slowed during the s.
In. Visit the Population Reference Bureau for much more information about human population growth. Visit Zero Population Growth for information about the problems of overpopulation.
Editor's note, 12/ ZPG has changed its name to Population Connection.
This brief statement of population problems indicates the pervasive and depressive effect that uncontrolled growth of population can have on many aspects of human welfare. Nearly all our economic, social, and political problems become more difficult to solve in the face of uncontrolled population.
This is a result of the growth in the population aged 65 and over. Between and there was a percentage point increase in the proportion of people aged 65 and over. It is projected to continue to grow to nearly a quarter of the population by For most species, their population growth is controlled by their carrying capacity, which is the maximum population size of a species that an ecosystem can support indefinitely.
For example, if a.