A U.S. of 300 million inhabitants is a number that cannot be sustained by the renewable services that nature can provide, like supplying clean water and maintaining clean air indefinitely. In fact, it is estimated¹ that the U.S. population would have to be half that in order sustain current living standards, that is, leaving the U.S. and the Earth such that those who follow us can live in the U.S. with the same or better quality of life that we enjoy.

In their monograph on projecting U.S population growth to 2050, the authors, Jack Martin and Stanley Fogel² recognize that, even under the best immigration reform scenario, U.S. population will continue to grow some 22 percent (65 million) by 2050 because, even after instituting policies which slow rapid growth, it is expected to take some time before growth stops and begins a gradual decline to the desired sustainable level.

But the authors estimate that, if Congress and the Administration carry out “current proposals to increase immigration, give legal status to those currently here illegally and create a new guest worker program,” an additional 135 million will be added by 2050, bringing U.S. population to the half billion mark by mid-century. Such U.S. growth in the twenty-first century would be comparable to the rapid growth experienced by China and India in the twentieth century which brought their populations at century’s end to around the 1 billion mark.

From an environmental perspective, the addition of 200 million people to today’s U.S. population of some 300 million over the next 45 years would be extremely destructive because population size is the major determinant of environmental impact.

It would be of more than just domestic concern because U.S. population size and consumption have a larger global effect than that of people anywhere else, an impact currently greater than that of China and India combined! Our cars and industrial processes cause some 30 percent of all greenhouse gases responsible for global warming, climate change, and increasingly destructive weather events. And the U.S. is the major contributor of the gases which cause thinning of the protective stratospheric ozone layer.

Up close, considering “environment” as our immediate surroundings, it’s obvious that the increase would bring more congestion, delays, crowding, public expenditure for additional needed infrastructure, and faster depletion of finite resources (coal, oil, gas, and mineral commodities) which would be reflected in higher prices, as is already happening.

While humans can adapt to change relatively quickly, plants, and animals generally cannot. So, the impact on ecosystems and even on inanimate systems such as glaciers would be far greater than the impact on people, at least initially.

But a 67 percent increase in U.S. population, within a timeframe of about three-fifths of an average U.S. lifetime, is so large and so fast that, even for humans, adjustment would not be easy.
While our concerns are global, an environmental focus on the U.S. makes sense.

First, the U.S. is our habitat. We want to maintain its natural endow-ments for future generations. Second, the U.S. population is growing, albeit needlessly, at a far faster rate than that of any other large industrialized nation. Third, the U.S. is looked upon as an example by many Third World nations whose people equate our pop-ulation growth with economic success. Fourth, as noted above, because of our huge ecological footprint, the Earth can’t afford any more Americans.

Our population growth impacts other species mainly through competition for habitat and food. It impacts inanimate nature through increasing use of topsoil, pasture, forest, and waters, often in irreversible ways like wind- and water-erosion, salinization, coastal salt-water intrusion, desertification and pre-empting of lands and waters through paving, mining, drilling, damming, over-pumping of ground- and surface-water sources, draining of wetlands, siltation, and air and water pollution, particularly toxic pollution.

The environmental impact of a huge, rapid increase in U.S. population, today due mainly to a continuing immigration boom, the highest numbers in American history (Fig.1), would be greater than the considerable impact of the post-WWII Baby Boom (1945-70), a 46 percent jump over a 25-year span, occurring when our population was some 170 million, less than 60 percent of today’s.
That earlier pop- ulation surge had an enormous impact on urbanization, growth in energy demand, and in expansion of highways and other infrastructure, encouraging sprawl. It ushered in new concerns about pollution, smog, acid rain and nuclear accidents.
Today the Boom would be starting from not only a much larger U.S. population number but also a much-depleted natural base. U.S. population is already so large that many water supplies are no longer being renewed naturally at a sustainable rate. Air pollution is endemic in urban and industrial areas and downwind from them. Even Grand Canyon, Great Smoky and other National Parks are impacted! Less than half of America’s waters are safe enough for fishing and swimming. Even the Great Lakes are seriously polluted,³ particularly from heavily populated areas like many others where expenditure for sewage treatment and overflow-prevention facilities have not kept up with population growth.

In efforts to meet the demand for fossil fuel, minerals and timber, natural areas are increasingly encroached upon and exploited. Our overpopulation has put some 1,300 U.S. plant and animal species on the threatened and endangered list.⁴ Some have already been rendered extinct.
Today’s unsustainable U.S. population growth is mainly the result of adoption by Congress and the Administration of outdated nineteenth century-era open immigration, pre-environmental-preservation policies. And our government encourages the births of more than replacement numbers of children by offering tax credits and other incentives and by instituting impediments to family planning.

An environmental perspective recognizes that long-term sustainable population numbers are limited by the essential, ecosystem services that nature can provide renewably. And it recognizes that U.S. numbers have exceeded that limit since the 1950s. Government policies which directly or indirectly encourage increase in U.S. population are therefore irresponsible, rob the future and must be rejected.   

End Notes

1. Paul & Anne Ehrlich, “The Most Overpopulated Nation,” Chap. 10, Elephants in the Volkswagen, Ed. Lindsey Grant, W.H. Freeman 1992.

2. Jack Martin & Stanley Fogel, “Projecting the U.S. Population to 2050: Four Immigration Scenarios”, FAIR, March 2006.

3. www.gcbl.org/water/lake-erie/great-
lakes-ecological-tipping-points

4. U.S. Fish & Wildlife Service, http://ecos.fws.gov/tess_public/Boxscore.do

Demographic and Regional Breakdowns of U.S. Foreign-Born Population: The pie chart shows the ethnic composition of California public schools (2002-2003); two graphs (above) visually show the regional origins and educational levels of the foreign-born population in the U.S.