Friday, April 11, 2008


The following two pages are highlights of the study, "Food, Land, Population, and the U.S. Economy" by Drs. David Pimentel of Cornell University and Mario Giampietro of the Istituto Nazionale della Nutrizione, Rome.

This comprehensive assessment of U.S. population growth and its impact on America's agricultural productivity was commissioned by Carrying Capacity Network (CCN), a non-profit organization in Washington, DC which focuses on the interrelated nature of the economy, population growth, and environmental degradation.

At the present growth rate of 1.1% per year, the U.S. population will double to more than half a billion people within the next 60 years. It is estimated that approximately one acre of land is lost due to urbanization and highway construction alone for every person added to the U.S. population.

This means that only 0.6 acres of farmland would be available to grow food for each American in 2050, as opposed to the 1.8 acres per capita available today. At least 1.2 acres per person is required in order to maintain current American dietary standards. Food prices are projected to increase 3 to 5-fold within this period.

If present population growth, domestic food consumption and topsoil loss trends continue, the U.S. will most likely cease to be a food exporter by approximately 2025 because food grown in the U.S. will be needed for domestic purposes.

Since food exports earn $40 billion for the U.S. annually, the loss of this income source would result in an even greater increase in America's trade deficit.

Considering that America is the world's largest food exporter, the future survival of millions of people around the world may also come into question if food exports from the U.S. were to cease.
Drs. Pimentel and Giampietro have concluded that U.S. population growth is a primary cause of these harsh potential outcomes. The study explains that the United States is the fastest-growing industrialized country in the world, now increasing by approximately three million people per year. This population growth rata is equivalent to adding 58,000 people per week or a city the size of Washington, D.C. to our country every year. The overall growth rate of the U.S. population has escalated in large part because of the unprecedented number of immigrants that have been allowed to come into the United States and their disproportionately higher birth rates compared to the native-born. About half of U.S. population growth is currently the result of immigration.


Land: On-going soil erosion and expanding urbanization contribute to the continuous loss of cropland in the U.S. Annually, more than two million acres of prime cropland are lost to erosion, salinization, and waterlogging. In addition, more than one million acres are removed from cultivation as America's limited arable land is Overwhelmed by the demands of urbanization, transportation networks, and industry. As a result of arable land shortages, U.S. meat consumption may be reduced.

Water: The groundwater that provides 31% of the water used in agriculture is being depleted up to 160% faster than its recharge rate. The vast U.S. Ogallala aquifer (under Nebraska, Oklahoma, and Texas) will likely become non-productive within the next 40 years. Even if water management is substantially improved, the projected 520 million Americans in 2050 would have about 700 gallons/day/capita, considered the minimum for all human needs, including agriculture.

Energy: The availability of non-renewable fossil energy explains in part the historically high productivity of U.S. agriculture. Currently the 400 gallons of oil equivalents expended to feed each American amount to about 17% of all energy used in this country each year. Yet given current use levels, only 15 to 20 years of oil resources remain in the U.S. Although imports now account for 58% of oil used in the U.S., these international reserves are expected to be exhausted within the next 30 to 50 years.

Given current depletion rates of land, water, and energy resources, U.S. agricultural productivity is already unsustainable. Should the U.S. population double within the next 60 years, the subsequent decrease in arable land will substantially change American eating habits and dramatically reduce future food exports. If Americans want continued access to abundant and affordable food with the ability to continue exporting food, we must work together to stop U.S. population growth and conserve our country's limited land, water, and energy resources in order to achieve a sustainable American future.

*carrying capacity refers to the number of individuals who can be supported without degrading the natural, cultural, and social environment, i.e. without reducing the ability of the environment to sustain the desired quality of life over the long term.

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