the concept can quickly become contentious on closer inspection. For most people, it means there are too many people in a given place. Sometimes the concept is used in terms of a city or country, while other times it is seen in global terms, focusing on the question of how many people planet Earth can support. The concept can become contentious because defining “too many” people is very subjective. When stuck in traffic on the freeway, people may say their city is overpopulated. If housing is too expensive or jobs are scarce, people may say the same thing. But in these cases, it can also be argued that the problem is not too many people but too little public transit, too little housing, or not enough economic growth (figure 2.39).
Figure 2.37.Weeks of maternity leave. Many countries offer paid maternity leave to help women balance having children with remaining in the paid workforce. Explore this map at http://arcg.is/2laPTHp. Laura Addati, Naomi Cassirer and Katherine Gilchrist. 2014.
Figure 2.38.Percentage of women with maternity leave coverage. Especially in poorer countries, paid maternity leave covers only a small fraction of women, since few have formal employment contracts with benefits. Explore this map at http://arcg.is/2laTAwH. Laura Addati, Naomi Cassirer, and Katherine Gilchrist, 2014.
The definition of overpopulation can be limited to the concept of carrying capacity: the number of people that can be supported by the land they live on. This can be seen in terms of land for food, clean air for breathing, and clean water for drinking. But this definition also leads to problems. First, as discussed earlier in this chapter, human populations can be very dense without being overpopulated and, via trade, can exceed their local carrying capacity. Food and water can be brought in from far away to support millions of people. For instance, Los Angeles, California, gets the majority of its water via canals from the northern parts of the state and the Colorado River, and most food is imported from other parts of California, the United States, and the world. Thus, the concepts of overpopulation and carrying capacity depend a great deal on infrastructure, technology, and economic development. Places with sufficient infrastructure, technology, and economic development can use resources from around the world and support massive, dense populations. Places without these advantages can more easily be considered overpopulated because their populations face shortages of food, water, and other resources. There is no fixed population density that can be considered an overpopulation threshold.
Figure 2.39.Is the world overpopulated? Defining the concept can be difficult to agree on. Crowds in Times Square, Manhattan. A lone farmhouse in Tuscany, Italy. Times Square photo by Andrew F. Kazmierski. Stock photo ID: 36538936 Shutterstock. Tuscany photo by Shaiith. Stock photo ID: 141591835. Shutterstock.
Although overpopulation is difficult to define at a local scale, many argue that at a global-scale population will eventually outstrip the earth’s carrying capacity. A 2012 report by the United Nations Environmental Program states that most estimates of the earth’s carrying capacity fall within a fairly wide range of eight to sixteen billion people. As of 2015, the United Nations median estimate for total world population by the year 2100 was 11.2 billion people, a point where population growth may level out.
Earth’s carrying capacity will depend on several factors. One is how much technology can help humans use resources more efficiently. If goods and services can be produced with less energy and material inputs, then the world will be able to support a larger number of people. One reason Malthus has not yet been proven correct is that technological innovations allow more food to be produced with less land, labor, and capital resources. Another factor is the global standard of living. If all 11.2 billion people in the year 2100 live at the same standard of living that Americans do today, then there will be a much greater strain on resources. Consumption of energy and other resources per capita is much higher in the United States and other rich countries than in less developed countries. Technological innovation will have to improve efficiency dramatically to support increased levels of consumption as people get richer.
References
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Organisation
