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Excerpts from

A Joint Statement by Fifty-eight of the World's Scientific Academies

[Reprinted with permission from the National Academy Press.]

Representatives of national academies of science from throughout the world met in New Delhi, India, from October 24-27, 1993, in a "Science Summit" on World Population. The conference grew out of two earlier meetings, one of the Royal Society of London and the United States National Academy of Sciences, and the other an international conference organized by the Royal Swedish Academy of Sciences. Statements published by both groups* expressed a sense of urgent concern about the expansion of the world's population and concluded that if current predictions of population growth prove accurate and patterns of human activity on the planet remain unchanged, science and technology may not be able to prevent irreversible degradation of the natural environment and continued poverty for much of the world.

The New Delhi conference, organized by a group of fifteen academies, was convened to explore in greater detail the complex and interrelated issues of population growth, resource consumption, socioeconomic development, and environmental protection. We believe it to be the first large-scale collaborative activity undertaken by the world's scientific academies.

This statement, signed by representatives of fifty-eight academies, reflects continued concern about the intertwined problems of rapid population growth, wasteful resource consumption, environmental degradation, and poverty. In keeping with the critical focus of the conference, the statement deals primarily with population. The academies believe that the ultimate success in dealing with global social, economic, and environmental problems cannot be achieved without a stable world population. The goal should be to reach zero population growth within the lifetime of our children.

* Population Growth, Resource Consumption, and a Sustainable World, a joint statement by the officers of the Royal Society of London and the U.S. National Academy of Sciences, 1992; Statement Issued by the International Conference on Population, Natural Resources, and Development, organized by the Royal Swedish Academy of Sciences and the Swedish Council for Planning and Coordination of Research, Stockholm, Sweden, 30 September - 3 October, 1991. See also: An Agenda of Science for Environment and Development into the 21st Century, based on a conference convened by the International Council of Scientific Unions in Vienna, Austria, in November 1991, Cambridge University Press, 1992; World Scientists' Warning to Humanity, statement signed by 1600 scientists, Union of Concerned Scientists, 1992.

THE GROWING WORLD POPULATION

The world is in the midst of an unprecedented expansion of human numbers. It took hundreds of thousands of years for our species to reach a population level of 10 million, only 10,000 years ago. This number grew to 100 million people about 2,000 years ago and to 2.5 billion by 1950. Within less than the span of a single lifetime, it has more than doubled to 5.5 billion in 1993.

This accelerated population growth resulted from rapidly lowered death rates (particularly infant and child mortality rates), combined with sustained high birth rates. Success in reducing death rates is attributable to several factors: increases in food production and distribution, improvements in public health (water and sanitation) and in medical technology (vaccines and antibiotics), along with gains in education and standards of living within many developing nations.

Over the last 30 years, many regions of the world have also dramatically reduced birth rates. Some have already achieved family sizes small enough, if maintained, to result eventually in a halt to population growth. These successes have led to a slowing of the world's rate of population increase. The shift from high to low death and birth rates has been called the "demographic transition."

The rate at which the demographic transition progresses worldwide will determine the ultimate level of the human population. The lag between downward shifts of death and birth rates may be many decades or even several generations, and during these periods population growth will continue inexorably. We face the prospect of a further doubling of the population within the next half century. Most of this growth will take place in developing countries.

Consider three hypothetical scenarios * for the levels of human population in the century ahead:

Fertility declines within sixty years from the current rate of 3.3 to a global replacement average of 2.1 children per woman. The current population momentum would lead to at least 11 billion people before leveling off at the end of the 21st century.

Fertility reduces to an average of 1.7 children per woman early in the next century. Human population growth would peak at 7.8 billion persons in the middle of the 21st century and decline slowly thereafter.

Fertility declines to no lower than 2.5 children per woman. Global populatlon would grow to 19 billion by the year 2100, and to 28 billion by 2150.

The actual outcome will have enormous implications for the human condition and for the natural environment on which all life depends.

* Population Reference Bureau, The UN. Long-Range Population Projections: What They Tell Us, Washington, D. C., 1992.

POPULATION GROWTH, RESOURCE CONSUMPTION, AND THE ENVIRONMENT

Throughout history, and especially during the twentieth century, environmental degradation has primarily been a product of our efforts to secure improved standards of food, clothing, shelter, comfort, and recreation for growing numbers of people. The magnitude of the threat to the ecosystem is linked to human population size and resource use per person. Resource use, waste production and environmental degradation are accelerated by population growth. They are further exacerbated by consumption habits, certain technological developments, and particular patterns of social organization and resource management.

THE EARTH IS FINITE

The growth of population over the last half century was for a time matched by similar world-wide increases in utilizable resources, However, in the last decade food production from both land and sea has declined relative to population growth. The area of agricultural land has shrunk, both through soil erosion and reduced possibilities of irrigation. The availability of water is already a constraint in some countries. These are warnings that the earth is finite, and that natural systems are being pushed ever closer to their limits.