World Population:
A Joint Statement by 58 of the World's Scientific Academies

In a follow-up to several recent initiatives by assemblies of scientists and scientific academies, most notably one taken by the Royal Society of London and the US National Academy of Sciences that resulted in a joint statement, "Population Growth, Resource Consumption, and a Sustainable World, '' issued in February 1992 (see Documents, PDR, June 1992), representatives of national academies of science from throughout the world met in New Delhi, 24-27 October 1993, at a ''Science Summit'' on World Population. The participants issued a statement, signed by representatives of 58 academies. The statement offers a wide-ranging if ex cathedra-style discussion of population issues related to development, notably on the determinants of fertility and concerning the effect of demographic growth on the environment and the quality of life. It also sets forth policy propositions, with emphasis on contributions that ''scientists, engineers, and health professionals'' can make to the solution of population problems. The statement finds that ''continuing population growth poses a great risk to humanity, '' and proposes a demographic goal, albeit with a rather elusive specification of a time frame: "In our judgement, humanity's ability to deal successfully with its social, economic, and environmental problems will require the achievement of zero population growth within the lifetime of our children. '' The text of the academies ' statement is reproduced below.

The New Delhi meeting was convened by a group of 15 academies "to explore in greater detail the complex and interrelated issues of population growth, resource consumption, socioeconomic development, and environmental protection.'' One of the convening organizations, the Nairobi-based African Academy of Sciences, declined to sign the joint statement, issuing, instead, one of its own. The text of this statement is reproduced below as the second Documents item appearing in this issue. Other academies that did not participate in the New Delhi meeting, or did not choose to sign the joint statement (whether for substantive or procedural reasons), included academies of Ireland, Italy, Japan, Singapore, and Spain, and the Pontifical Academy of Sciences. Notwithstanding the African Academy dissent, representatives of six African national academies, among them four from countries of sub-Saharan Africa (Ghana, Kenya, Nigeria, and Uganda) were among the fifty-eight signatories.

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 population would grow to 19 billion by the year 2100, and to 28 billion by 2150.

Key determinants of population growth

High fertility rates have historically been strongly correlated with poverty, high childhood mortality rates, low status and educational levels of women, deficiencies in reproductive health services, and inadequate availability and acceptance of contraceptives. Falling fertility rates and the demographic transition are generally associated with improved standards of living, such as increased per capita incomes, increased life expectancy, lowered infant mortality, increased adult literacy, and higher rates of female education and employment.

Even with improved economic conditions, nations, regions, and societies will experience different demographic patterns due to varying cultural influences. The value placed upon large families (especially among underprivileged rural populations in less developed countries who benefit least from the process of development), the assurance of security for the elderly, the ability of women to control reproduction, and the status and rights of women within families and within societies are significant cultural factors affecting family size and the demand for family planning services.

Even with a demand for family planning services, the adequate availability of and access to family planning and other reproductive health services are essential in facilitating slowing of the population growth rate. Also, access to education and the ability of women to determine their own economic security influence their reproductive decisions.

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.

As human numbers further increase, the potential for irreversible changes of far reaching magnitude also increases. Indicators of severe environmental stress include the growing loss of biodiversity, increasing greenhouse gas emissions, increasing deforestation worldwide, stratospheric ozone depletion, acid rain, loss of topsoil, and shortages of water, food, and fuel-wood in many parts of the world.

While both developed and developing countries have contributed to global environmental problems, developed countries with 85 percent of the gross world product and 23 percent of its population account for the largest part of mineral and fossil-fuel consumption, resulting in significant environmental impacts. With current technologies, present levels of consumption by the developed world are likely to lead to serious negative consequences for all countries. This is especially apparent with the increases in atmospheric carbon dioxide and trace gases that have accompanied industrialization, which have the potential for changing global climate and raising sea level.

In both rich and poor countries, local environmental problems arise from direct pollution from energy use and other industrial activities, inappropriate agricultural practices, population concentration, inadequate environmental management, and inattention to environmental goals. When current economic production has been the overriding priority and inadequate attention has been given to environmental protection, local environmental damage has led to serious negative impacts on health and major impediments to future economic growth. Restoring the environment, even where still possible, is far more expensive and time consuming than managing it wisely in the first place; even rich countries have difficulty in affording extensive environmental remediation efforts.

The relationships between human population, economic development, and the natural environment are complex. Examination of local and regional case studies reveals the influence and interaction of many variables. For example, environmental and economic impacts vary with population composition and distribution, and with rural-urban and international migrations. Furthermore, poverty and lack of economic opportunities stimulate faster population growth and increase incentives for environmental degradation by encouraging exploitation of marginal resources.

Both developed and developing countries face a great dilemma in reorienting their productive activities in the direction of a more harmonious interaction with nature. This challenge is accentuated by the uneven stages of development. If all people of the world consumed fossil fuels and other natural resources at the rate now characteristic of developed countries (and with current technologies), this would greatly intensify our already unsustainable demands on the biosphere. Yet development is a legitimate expectation of less developed and transitional countries.

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.

Quality of life and the environment

Our common goal is improving the quality of life for all people, those living today and succeeding generations, ensuring their social, economic, and personal well-being with guarantees of fundamental human rights; and allowing them to live harmoniously with a protected environment. We believe that this goal can be achieved, provided we are willing to undertake the requisite social change. Given time, political will, and intelligent use of science and technology, human ingenuity can remove many constraints on improving human welfare worldwide, finding substitutes for wasteful practices, and protecting the natural environment.

But time is short and appropriate policy decisions are urgently needed. The ability of humanity to reap the benefits of its ingenuity depends on its skill in governance and management, and on strategies for dealing with problems such as widespread poverty, increased numbers of aged persons, inadequate health care and limited educational opportunities for large groups of people, limited capital for investment, environmental degradation in every region of the world, and unmet needs for family planning services in both developing and developed countries. In our judgement, humanity's ability to deal successfully with its social, economic, and environmental problems will require the achievement of zero population growth within the lifetime of our children.

Human reproductive health

The timing and spacing of pregnancies are important for the health of the mother, her children, and her family. Most maternal deaths are due to unsafe practices in terminating pregnancies, a lack of readily available services for high-risk pregnancies, and women having too many children or having them too early and too late in life.

Millions of people still do not have adequate access to family planning services and suitable contraceptives. Only about one-half of married women of reproductive age are currently practicing contraception. Yet as the director-general of UNICEF put it, ''Family planning could bring more benefits to more people at less cost than any other single technology now available to the human race." Existing contraceptive methods could go far toward alleviating the unmet need if they were available and used in sufficient numbers, through a variety of channels and distribution, sensitively adapted to local needs.

But most contraceptives are for use by women, who consequently bear the risks to health. The development of contraceptives for male use continues to lag. Better contraceptives are needed for both men and women, but developing new contraceptive approaches is slow and financially unattractive to industry. Further work is needed on an ideal spectrum of contraceptive methods that are safe, efficacious, easy to use and deliver, reasonably priced, user-controlled and responsive, appropriate for special populations and age cohorts, reversible, and at least some of which protect against sexually transmitted diseases, including AIDS.

Reducing fertility rates, however, cannot be achieved merely by providing more contraceptives. The demand for these services has to be addressed. Even when family planning and other reproductive health services are widely available, the social and economic status of women affects individual decisions to use them. The ability of women to make decisions about family size is greatly affected by gender roles within society and in sexual relationships. Ensuring equal opportunity for women in all aspects of society is crucial.

Thus all reproductive health services must be implemented as a part of broader strategies to raise the quality of human life. They must include the following:

• Efforts to reduce and eliminate gender-based inequalities. Women and men should have equal opportunities and responsibilities in sexual, social, and economic life.
• Provision of convenient family planning and other reproductive health services with a wide variety of safe contraceptive options. irrespective of an individual's ability to pay.
• Encouragement of voluntary approaches to family planning and elimination of unsafe and coercive practices.
• Development policies that address basic needs such as clean water, sanitation, broad primary health care measures and education; and that foster empowerment of the poor and women.

Sustainability of the natural world as everyone's responsibility

In addressing environmental problems, all countries face hard choices. This is particularly so when it is perceived that there are short-term tradeoffs between economic growth and environmental protection, and where there are limited financial resources. But the downside risks to the earth—our environmental life support system—over the next generation and beyond are too great to ignore. Current trends in environmental degradation from human activities combined with the unavoidable increase in global population will take us into unknown territory.

Other factors, such as inappropriate governmental policies, also contribute in nearly every case. Many environmental problems in both rich and poor countries appear to be the result of policies that are misguided even when viewed on short-term economic grounds. If a longer-term view is taken, environmental goals assume an even higher priority.

The prosperity and technology of the industrialized countries give them greater opportunities and greater responsibility for addressing environmental problems worldwide. Their resources make it easier to forestall and to ameliorate local environmental problems. Developed countries need to become more efficient in both resource use and environmental protection, and to encourage an ethic that eschews wasteful consumption. If prices, taxes, and regulatory policies include environmental costs, consumption habits will be influenced. The industrialized countries need to assist developing countries and communities with funding and expertise in combating both global and local environmental problems. Mobilizing "technology for environment" should be an integral part of this new ethic of sustainable development.

For all governments it is essential to incorporate environmental goals at the outset in legislation, economic planning, and priority setting; and to provide appropriate incentives for public and private institutions, communities, and individuals to operate in environmentally benign ways. Tradeoffs between environmental and economic goals can be reduced through wise policies. For dealing with global environmental problems, all countries of the world need to work collectively through treaties and conventions, as has occurred with such issues as global climate change and biodiversity, and to develop innovative financing mechanisms that facilitate environmental protection.

What science and technology can contribute toward enhancing the human prospect

As scientists cognizant of the history of scientific progress and aware of the potential of science for contributing to human welfare, it is our collective judgement that continuing population growth poses a great risk to humanity. Furthermore, it is not prudent to rely on science and technology alone to solve problems created by rapid population growth, wasteful resource consumption, and poverty.

The natural and social sciences are nevertheless crucial for developing new understanding so that governments and other institutions can act more effectively, and for developing new options for limiting population growth, protecting the natural environment, and improving the quality of human life.

Scientists, engineers, and health professionals should study and provide advice on:

• Cultural, social, economic, religious, educational, and political factors that affect reproductive behavior, family size, and successful family planning.
• Conditions for human development, including the impediments that result from economic inefficiencies: social inequalities; and ethnic, class, or gender biases.
• Global and local environmental change (affecting climate, biodiversity, soils, water, air), its causes (including the roles of poverty, population growth, economic growth, technology, national and international politics), and policies to mitigate its effects.
• Strategies and tools for improving all aspects of education and human resource development, with special attention to women.
• Improved family planning programs, contraceptive options for both sexes, and other reproductive health services, with special attention to needs of women; and improved general primary health care, especially maternal and child health care.
• Transitions to economies that provide increased human welfare with less consumption of energy and materials.
• Improved mechanisms for building indigenous capacity in the natural sciences, engineering, medicine, social sciences, and management in developing countries, including an increased capability of conducting integrated interdisciplinary assessments of societal issues.
• Technologies and strategies for sustainable development (agriculture, energy, resource use, pollution control, materials recycling, environmental management and protection).
• Networks, treaties, and conventions that protect the global commons.
• Strengthened world-wide exchanges of scientists in education, training, and research.

Humanity is approaching a crisis point with respect to the interlocking issues of population, environment, and development. Scientists today have the opportunity and responsibility to mount a concerted effort to confront our human predicament. But science and technology can only provide tools and blueprints for action and social change. It is the governments and international decision-makers, including those meeting in Cairo next September at the United Nations International Conference on Population and Development, who hold the key to our future. We urge them to take incisive action now and to adopt an integrated policy on population and sustainable development on a global scale. With each year's delay the problems become more acute. Let 1994 be remembered as the year when the people of the world decided to act together for the benefit of future generations.

Reprinted from Population and Development Review, Vol. 20, no. 1 (March 1994):233-238

See also The Population Explosion by Paul and Anne Ehrlich.

Jay Hanson

Whatta Hero!

Mizaru, kikazaru, iwazaru.

If you are intimidated, bored or angered by Plato, Aristotle, Cousteau, Malthus, Mill or Ehrlich, don't bother pointing your browser to Brain Food. It is interesting to consider that, "ehrlich" is an indication of Paul Ehrlich's truthfulness, for his very name means "honest, sincere and fair," in the German language.

See Also THE POPULATION EXPLOSION by Paul and Anne Ehrlich.