The census bureau middle series population projections indicate that our population will double again by the end of this century. How will double the number of Americans treat the environment of their country and the world? Remarkably, as a result of sustained national commitment and hundreds of billions of dollars, many environmental indices are actually better today than at the time of the first Earth Day in 1970, in spite of some 70 million more Americans. But we would be fooling ourselves if we thought this progress constituted "sustainable development," or that it "meets the needs of the present without compromising the ability of future generations to meet their own needs." Much of our economic growth and concurrent environmental progress rest precariously on what environmental visionary David Brower once called "Strength Through Exhaustion."
Our growing energy consumption, carbon dioxide emissions, farmland and topsoil loss, and endangered species are all symptomatic of a nation headed the wrong way on the path to sustainability. Yet conventional wisdom holds that both population and per capita resource consumption will grow tremendously in the new century.
U.S. energy consumption increased 22 percent from 1973 to 1995, with growing dependence on finite reserves of gas, coal, and imported oil.29 Population growth accounted for about 90 percent of this. The 1991 National Energy Strategy forecasted moderate growth in U.S. energy use in the coming decades, more or less matching population growth. If per capita energy consumption remains constant by dint of ever-increasing energy efficiency, then total U.S. energy consumption will still double along with population over the coming century. But national and world petroleum and natural gas reserves are likely to dwindle to insignificance well before this. Competition for the world's remaining oil, much of it concentrated in the volatile Middle East, will be a source of escalating global insecurity. However, the United States is richly endowed with two other fossil fuels: coal and oil shale. Unfortunately, both are plagued with egregious environmental problems: landscape disfigurement, heavy water demands, acid mine drainage, and high sulfur dioxide and carbon dioxide emissions. Technological optimists argue that growing energy needs could be met with some combination of nuclear fission, fusion, breeder reactors, solar thermal, photovoltaic cells, wind, biomass, and efficiency improvements, but none of these is problem-free. Even the "green" renewables are not panaceas: they are land-intensive, unsightly, and in the case of wind turbines, have even been implicated in bird kills. These optimists never address the question of why we would want to put ourselves in this position by allowing unfettered population growth.
Climatologists generally agree that global warming is underway and that human emissions of the so-called greenhouse gases, principally carbon dioxide (CO2 ) and methane (CH4), are responsible. The UN's conservative estimate of America's per capital annual emissions is 40 metric tons. If this rate remains unchanged, adding 300 million more people will produce 4 billion additional metric tons of pollutants per year. Without controls, the Intergovernmental Panel on Climate Change predicts that average global surface temperatures will rise by 2°C (4°F) and sea levels by 0.5 meters (1.7 feet) by 2100. Concern over possible economic and ecological ramifications led to the 1997 signing of the Kyoto Treaty in Japan. As the country with by far the largest industrial CO 2 emissions, the United States must play a major role in any international effort. In Kyoto, the Clinton-Gore administration committed the United States to reducing its CO 2 emissions to 7 percent below 1990 emissions by 2010, an ambitious but attainable goal. Yet a booming population-driven economy — and no firm resolve — have only served to boost our carbon emissions. We are moving away from the target rather than toward it; population growth in the United States almost doubles the required per capita reduction of carbon emissions needed. Why isn't population the principal focus of emission control and reduction discussions?
A continually growing population will also worsen urban sprawl. According to the U.S. Department of Agriculture, in the 1990s an average of three million acres per year of rural land was developed. If this rate continues to 2100, the United States will convert an additional 300 million acres of rural countryside. That's 470,000 square miles paved or otherwise built-up, equivalent to 57 percent of the land area of the 24 states east of the Mississippi River. To avoid this outcome through so-called "Smart Growth" initiatives and regional planning would mean drastically raising the density of existing built-up areas, as well as embracing mass transit whole-heartedly to avoid stifling traffic congestion. Overall, one effect of the projected population growth will be to increase government regulation's role in American society.
The combination of relentless development and land degradation will reduce America's productive agricultural land base even as the demands on that same land base from a growing population increase. If current rates continue to 2100, the nation will lose more than 300 million of its remaining 375 million acres of cropland, or 82 percent of it, even as the U.S. population grows from 275 million to 571 million. These trends have led some scientists to conclude that some day America may no longer enjoy a food surplus for export to the world. Cornell University agricultural and food scientists David and Marcia Pimentel and Mario Giampietro of the Istituto Nazionale della Nutrizione in Rome have argued that the United States could cease to export food by 2025.
Finally, while disappearing tropical rain forests, panda bears, polar bears and gorillas rightly worry Americans, we will have our hands full here with our own biodiversity crisis. Even at present, 371 globally rare terrestrial ecological communities are threatened in the United States. In 1996, the Nature Conservancy reported that almost one-third (32 percent) of 28,000 species and an additional 11,000 subspecies and varieties of plants and animals in the United States were in some danger. As U.S. population doubles and resource exploitation intensifies, pressures on precarious living resources can only increase.
Certainly it is well beyond the "head-counting" mission of the Census Bureau to address such profound questions. Yet one would have hoped for more from the country as a whole. But this is typical. In describing America's lackadaisical approach to energy, historian Otis Graham weighs the evidence that "the inevitable end of the petroleum era will begin to be felt in the first half of the twenty-first century, and the time to prepare for it has been poorly used."
The same might be said about other environmental bills that will be coming due. The nation with the greatest technical and financial means of any in the history of the world is postponing the difficult choices on the path to a sustainable future. Several years ago the President's Council on Sustainable Development advised that the United States move toward population stabilization. The Council's Population and Consumption Task Force added: "This is a sensitive issue, but reducing immigration levels is a necessary part of population stabilization and the drive toward sustainability." These recommendations went largely ignored. That, too, seems to be the fate of the latest projections on the demographic consequences of current immigration levels.
Many futurists have gotten egg on their faces by totally dismissing the prospects for major technological changes. It is less likely that this will be true of population projections and other future developments related to trends easily discernible today.
(major portions of this are taken from Leon Kolankiewicz's paper:
Population Time Bomb