1,000 in 2045-50. Overall, the rate of natural increase would decrease almost in half, from 5.8 to 3.1 per 1,000.²⁴

Under any of our positive net immigration scenarios, the size of the U.S. population will be higher in the future than it would be if net immigration were zero at this moment. The increase in the total size of the population in most of these positive immigration worlds would not be trivial. As we have just seen, simply holding immigration to current levels would mean a net addition of 80 million Americans by the year 2050. Should we care about whether the 2050 population is the 387 million implied by current immigration levels as opposed to the 307 million implied by the absence of net immigration?

Although we do not answer that question categorically in this volume, we spell out some important elements of the answer. Our reticence rests in part on our conviction that knowledge about many of the crucial parameters on which an informed answer should rest is still lacking.

The future size of the population is important for labor market, fiscal, social, and environmental reasons. Chapter 5 spells out our analysis of the labor market effects. As we explain there, the critical issue is the extent to which a larger population size for the United States may be associated with some economies or diseconomies of scale. For example, if the U.S. economy is characterized by economies of scale, then a 10 percent increase in population will mean more than a 10 percent increase in national output. For some specialized products, businesses with access to the large U.S. market may have a substantial advantage, compared with doing business in a country with a smaller market. Similarly, in large part, the net fiscal impact we estimate in Chapters 6 and 7 will simply be scaled up or down by the size of the immigration flow, as long as the composition of immigration remains constant.

It is less clear what the comparative advantages and limitations are for social and environmental matters. Some have argued that there may be some important congestion effects from a larger population. These congestion effects may reveal themselves in more crowded highways, schools, and parks. From an environmental perspective, a large and growing population places greater demands on the environment, other conditions being equal. Probably more important, however, from a demographic perspective, is the extent to which the population resides in environmentally sensitive areas and the per capita environmental effects of the population.

Front Matter (R1-R14)

Summary (1-13)

1 The Immigration Debate (14-19)

2 Background to Contemporary U.S. Immigration (20-75)

3 The Face of the U.S. Population in 2050 (76-134)

4 Immigration's Effects on Jobs and Wages: First Principles (135-172)

5 Immigration's Effects on Jobs and Wages: Empirical Evidence (173-253)

6 Do Immigrants Impose a Net Fiscal Burden? Annual Estimates (254-296)

7 The Future Fiscal Impacts of Current Immigrants (297-362)

8 The Social Dimensions of Immigration (363-406)

Biographical Sketches (407-412)

Index (413-434)