Projecting Population Growth to 2100

About the Programmatic Environmental Impact Statement Project


Immigration has a huge influence on the overall size of the U.S. population, and population size is an important factor in determining a variety of environmental impacts. In 2016, PFIR completed a three-year investigation culminating in a Programmatic Environmental Impact Statement (PEIS) analyzing the long-term, cumulative effects of immigration levels on America’s environmental resources.

We assessed six types of potential long-term environmental impacts associated with three alternative immigration scenarios: 1) No Action Alternative, in which current immigration rates of approximately 1.25 million per year would be maintained to the year 2100; 2) Expansion Alternative, or 2.25 million annual immigration; and 3) Reduction Alternative, or 0.25 million (250,000) annual immigration into the United States.

Potential 70 percent Population Increase by 2100

U.S. population size was projected to the year 2100 under the three alternative immigration scenarios. Fertility and mortality rates were held steady under all three alternatives, at the levels used by the U.S. Census Bureau in its 2008 projections.

The No Action Alternative would lead to a U.S. population of 524 million in 2100, an increase of 215 million (70 percent) over the 2010 population of 309 million. The Expansion Alternative would result in a U.S. population of 669 million in 2100, an increase of 360 million (117 percent) above the 2010 population of 309 million. The Reduction Alternative would lead to a U.S. population of 379 million in 2100, an increase of 70 million (23 percent) above the 2010 population of 309 million.

Potential environmental impacts for each of the three alternatives were assessed in six pertinent topic areas: 1) urban sprawl and loss of farmland; 2) habitat loss and impacts on biodiversity; 3) water demands and withdrawals from natural systems; 4) carbon dioxide emissions and resultant climate change; 5) energy demands and national security implications, and 6) international ecological impacts of U.S. immigration policies.

Taking No Action Means Significant, Long-Term Adverse Environmental Impacts

In general, the No Action Alternative (1.25 million annual immigration) and the Expansion Alternative (2.25 million annual immigration) would result in significant, long-term, widespread adverse environmental impacts on all resource topics analyzed. The Expansion Alternative in particular would result in major, highly adverse environmental impacts on a number of resources, even taking enhanced conservation and efficiency measures into account. The Reduction Alternative would still entail higher environmental impacts than at present, but much less than the other two alternatives.

In an era when radical agendas are pushing for open borders or essentially no borders at all, the findings of the PFIR PEIS are even more pertinent today than when they were released in 2016. If the radical agenda were to prevail, the long-term environmental impacts would be comparable to those described above for the Expansion Alternative: significant, highly adverse and widespread. They could be summarized more succinctly in a single word: devastating. If Americans opt for this course, we will doom posterity to an impoverished environment.

Read the Environmental Impact Statement (EIS) by Chapter:

Abstract and Executive Summary

Part I

Part II

Part III

Part IV


Full Environmental Statement:

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