How many people can the Earth adequately sustain? What is the impact of more and more people on the environment, on the global economy, on national security, on the quality of life for everyone?
Although there are no easy answers, the United Nations and the international community have made population and development issues a major priority.
Human population is growing exponentially. The Earth reached its first billion people in 1850. One hundred years later, in 1950, there were 2.52 billion. In less than 50 years, by 1994, the population had more than doubled again to 5.63 billion. The population of the world in 1995 was estimated at 5.7 billion people and is projected to pass the 6 billion mark in 1998. The annual rate of world population growth peaked at about 2 percent per year in the late 1960s. In the early 1990s, demographers and others observing population trends estimated that world population was growing by about 93 million people a year, the highest annual increment in human history. That figure had dropped by 1995 to approximately 86 million due to declining fertility rates in some of the world's most rapidly growing nations in sub-Saharan Africa such as Kenya, Tanzania, Mauritania and Zimbabwe.
The United Nations predicts that, if current trends continue, by the year 2050, the population will have increased from a low of 7.8 billion to a high of 12.5 billion, a figure that most experts agree is almost certainly not sustainable for the vast majority of people (World Population Prospects 1994, UN Publications).
One of the most serious problems facing humanity is the grossly uneven distribution of population growth, a result of the phenomenon known as demographic momentum. This is described as the proportion of people in various age grades and how that proportion, combined with changes in mortality, influences future birth rates.
There are significant differences among regions and even among countries within the same region. The clearest division is that between "more developed" and "less developed" countries. The developed industrialized regions comprise Northern America, Japan, Europe and Australia-New Zealand and are home to 1.2 billion people. As fertility and the proportion of people in their childbearing years continue to decline, population in these regions is growing at a rate of less than one-half of one percent per year, a rate that is projected to dip below zero soon after 2025.
Countries with large proportions of their current populations under age 15 will continue to experience substantial population growth as these young people enter their childbearing years. Among developing countries as a whole, more than one-third of the population is under age 15, compared with one-fifth of the population in industrialized countries. The population of less developed regions is estimated at 4.5 billion, with a growth rate of almost 1.9 percent. This demographic momentum ensures that over the next 30 years, more than 95 percent of population growth will take place in the developing countries that can least afford it.
Throughout the world, but particularly in developed countries, the growing proportion of the population over age 65 poses another dilemma for social security systems, whether governmental or private.
The strain placed by population on the Earth's resources and infrastructures is enormous. The most obvious is the demand for food. In 1995, there were 25 food emergencies addressed by the United Nations World Food Program. This number is almost certain to rise. Increased populations place more demands on the land for crop production, grazing land, water resources, firewood and living space. This leads to serious environmental degradation and decreased per capita production.
Furthermore, overcrowding in cities and lack of adequate clean water leads to the spread of diseases such as the outbreak of cholera, dysentery, and other communicable or water-born problems.
At the United Nations Conference on Population and Development held in Cairo in 1995, the member nations agreed on a Plan of Action to begin setting goals and implementing plans to regulate population growth. In 1996, the UN Habitat II Conference will address the problems of urbanization that are being created by increasing population pressures.
In almost every aspect of global management and governance, population must be considered as a critical factor. Gains in development, security, health and the quality life can only continue if global population growth is controlled to sustainable levels.
