Carrying capacity is defined as the number of individuals of a certain species that can be sustained indefinitely in a particular area. The Earths capacity to support people is determined both by natural constraints and by human choices concerning economics, environment, culture (including values and politics), and demography. Human carrying capacity is more difficult to estimate than some of the standard demographic indicators, like expectation of life or the total fertility rate, because human carrying capacity depends on populations and activities around the world.
Human carrying capacity is therefore dynamic and uncertain. Ecologists have often made use of the concept of carrying capacity in addressing the pressures that populations put on their environments. Many regions are already exceeding their carrying capacity; they cannot produce enough food to support their populations. One region where this is very clear is an enormous swath of equatorial Africa called the Sahel, that is undergoing very rapid desertification. The burgeoning populations of this area are contributing to its desertification by clearing forest for agriculture as well as for firewood.
In 1900, 40% of Ethiopia was covered by forest; now only 4% is forested (Cohen, 1995). The world’s population will soon reach a level where there will not be enough resources to sustain life, as we know it. During the last half-century, world population has more than doubled, climbing from 2. 5 billion in 1950 to 5. 9 billion in 1998. There has been more growth in population since 1950 than during the 4 million preceding years since our early ancestors first stood upright (Brown, Gardner, & Halweil, 1999).
This unprecedented surge in population, combined with rising individual consumption, is pushing our claims on the planet beyond its natural limits. Many environmental, social, and economic problems either stem from or are increased in magnitude by the overpopulation problem. With an exponentially increasing population, the problems created by overpopulation grow correspondingly. Population growth is out-spacing growth in agricultural production and it is putting increasing pressure on erodible soils, grazing lands, water, and fuel-wood supplies (Chapman, Peterson, & Smith-Moran, 2000).
To ensure population stability not only in the increasingly wealthy third-world areas, but also in the industrialized areas, countries and individuals must work together to achieve controlled population growth. The earth does not contain enough resources to indefinitely sustain the current enormous population growth. For instance, there only is a limited area of arable land and living space available to us. China, home to 1. 2 billion people or 1/5 the world’s population, is an excellent example of the kinds of problems that arise in an increasingly crowded society.
Trying to increase the standard of living of its people, China has industrialized and the economy has grown (Hanson, 1995). This increase in wealth has increased the demand for food in China. The demand is so great that China went from exporting 8 million tons of grain in 1992 to becoming a net importer of 16 million tons of grain in 1994 (China News Digest, 1995). This causes a worldwide grain shortage that raises prices, which in turn puts food out of reach of even more people. In many areas, there is simply not enough food to feed the growing populations.
Each day 40,000 children die from malnutrition and its related diseases. 150 million children in the world suffer from poor health due to food shortages (Turbak, 1992). Another resource, which cannot keep up with an increasing population, is water. The supply of fresh water is limited, especially since water tables are falling on every continent as demand exceeds the sustainable yield of aquifers. Also, the growing appetite for seafood has taken oceanic fisheries to their limits and beyond.
In addition to depleting resources, overpopulation is the root cause of most environmental problems. The demands of increasing population magnify demands for natural resources, clean air and water, as well as access to wilderness areas. Unless we start stacking people in high-rises, this means an increased demand for living space, with the inevitable result of more sprawl. The quality of life for future generations hinges on stabilizing both domestic and world population. Pollution is an environmental problem whose magnitude is increased by overpopulation.
Although rapid population growth leads to high rates of habitat loss, some of the greatest pollution problems (both local and global), and high levels of energy use, occur in areas with high densities (Asia and Europe) rather than in countries with high growth rates (Africa and South America). As more people drive more cars, use more electricity, throw away more trash, and cut down more trees, the environmental problems we experience are greatly increased. The traffic problems we face daily are another result of overpopulation.
In California, 300,000 hours are wasted in traffic congestion each year at an estimated annual cost of over 892 million dollars. In addition, these idling motors add to the pollution problem (Oberlink, 1995). The earth could easily sustain a small population of highly polluting people. But as more people such as us pollute, massive problems occur. Pollution is magnified in developing nations, as those nations with larger growing populations become richer; their pollution increases with their wealth. Developing nations often promote industries that pollute to compete economically.
These industries are less tightly regulated in order to stimulate growth. Besides causing the environmental strains on the earth, overpopulation causes a large number of the social problems in today’s society. A recent study by Ohio State University shows that children whose family sizes are larger did much worse in school. The research, published in October’s American Sociological Review, found that as family size increases, parents talk less to each child about school, have lower education expectations, save less for college and have fewer educational materials available (CAPS, 1995).
Successful steps have been made in fighting the problem of overpopulation. The first step, recognizing the problem, was reached by a British clergyman and intellectual, Thomas Malthus, warned in his Essay on the Principle of Population (1978) of the check on population growth provided by what he believed were coming constraints on food supplies. Malthus pointed out that population tends to grow exponentially while the food production grows only arithmetically; therefore the population must inevitably outgrow the supply of food.
The necessary effects of these two different rates of increase, when brought together are very striking. For example take the population of the Earth to be 11 millions; and suppose the present food production can easily support such a number. In the first twenty-five years the population would be 22 millions, and the food being also doubled, the means of subsistence would be equal to this increase. In the next twenty-five years, the population would be 44 millions, and the means of subsistence just equal to the support of 33 millions.
In the next period the population would be 88 millions, and the means of subsistence just equal to half that number. At the conclusion of the first century, the population would be 176 millions, and the means of subsistence only equal to the support of 55 millions; leaving a population of 121 millions totally unprovided for (Malthus, 1992). He postulated that population growth was already outpacing the production of food supplies in 18th-century England.
Malthus foresaw massive food shortages and famine as an inevitable consequence of population growth. He mentioned “positive checks” such as war, famine, and disease, and “preventative checks” such as celibacy and contraception (Microsoft Encarta 1998). The world’s population will soon reach a level where there will not be enough resources to sustain life, as we know it.
During the last half-century, world population has more than doubled, climbing from 2. 5 billion in 1950 to 5. illion in 1998. There has been more growth in population since 1950 than during the 4 million preceding years since our early ancestors first stood upright (Brown, Gardner, & Halweil, 1999). This unprecedented surge in population, combined with rising individual consumption, is pushing our claims on the planet beyond its natural limits. Many environmental, social, and economic problems either stem from or are increased in magnitude by the overpopulation problem.
With an exponentially increasing population, the problems created by overpopulation grow correspondingly. Population growth is out-spacing growth in agricultural production and it is putting increasing pressure on erodible soils, grazing lands, water, and fuel-wood supplies (Chapman, Peterson, & Smith-Moran, 2000). To ensure population stability not only in the increasingly wealthy third-world areas, but also in the industrialized areas, countries and individuals must work together to achieve controlled population growth.
