Fall 1994

The Earth's Overpopulation Crisis
Susan Chien

    In an age burdened by environmental concerns and worries of the future quality of life for humans, David Pimentel, Professor of Ecology and Systematics, and a group at Cornell, determined the earth and its resources could sustain an "optimum population" of two billion people indefinitely. The current world population stands at about 5.6 billion.

    On February 21, Pimentel addressed the annual meeting of the American Association for the Advancement of Science (AAAS) in a session on societal change with the results of his findings. He explained that although such a drastic population decrease would cause social, economic, and political problems, a continuing population growth would bring on even more catastrophic effects in these areas and would also lead to public health and environmental problems.

    "I am aiming to start a discussion and ask people if this is what we want for our future. Do we as humans want to control our numbers intellectually, or do we want nature to control it?" Pimentel said. In reference to the results of his findings, he said, "It will affect our freedom to reproduce, but if changes are not made, we will lose our freedom to hunger, starvation and poverty."

    The Cornell ecologists tried to cover all the factors important for sustaining human life in their study - land fertility, energy, water, biodiversity and many others. By compiling published data pertaining to per capita water consumption and agricultural land utilization, the group made their conclusions. The cummulative results yielded some startling statistics.

    98 percent of the world's food comes from the terrestrial environment, but land degradation will cause food production to drop by 20 percent over the next 25 years. Each year, 25 million acres of arable land are destroyed due to water and wind erosion, salinization, and water logging of soils. Additionally, the growing use of synthetic pesticides has increased crop losses. These statistics forecast an inability to sustain a growing population, for 13 million acres of land for food production must be allocated each year to keep up with the 92 million people added annually to the world's numbers. Fresh water supplies are also in great jeopardy and stand to severely limit the world's population. Even now, groundwater cannot be replenished as quickly as it is consumed. Additionally, the projection for the year 2100 requires 1.2 acres of cropland per capita, which is the current level in the United States, to ensure a healthy selection of food for the human diet. However, the world average is currently 0.7 acres per capita and falling.

    Published studies also predict that most of the world's fossil fuel and uranium reserves will be depleted by 2100, forcing people to shift their dependency to renewable energy sources. With new and more efficient sources of energy, Americans may be able to cut their energy consumption in half and allow other inhabitants of the world to improve their standard of living. Currently, the average American citizen consumes 23 times more goods than the average third-world citizen, and 53 times more than a Chinese citizen.

    With the degradation and destruction of the environment, the world's natural biota is also suffering. The plants, animals, and microbes perform vital functions that humans cannot provide for themselves, including pollinating crops and plants, recycling organic wastes, degrading chemical pollutants, and purifying water and soil. The role of the natural biota in maintaining the environment is crucial. Although concern for environmental issues has increased, Pimentel still feels the population dilemma has been left in the dark - "I am disappointed with many environmentalists. They do not want to deal with the population issue."

    An in-depth look at the study, supported by the Laurel Foundation, was published in the May 1994 issue of Population and Environment. Cornell students Rebecca Harman, Matthew Pacenza, Jason Pecarsky, and human ecologist Marcia Pimentel worked with Professor Pimentel in researching the topic and making the projections.