Is there Hope?: Examining Overpopulation and the Environment Using the Kuznets Curve

Reshma Pattni

   There are many theories about the number of people the earth can sustain in the long run. The estimates range from 1or 2 billion to a very high, but unspecified maximum of the human population. Each of these is based on some interpretation of the facts of the effect that humans have on the environment, but we can not be sure which theory will be the right one in the end. In the past, population grew at a much slower rate than in recent history. Current population growth has been more rapid. In the last two centuries, population has increased from 1 billion in 1800 to 1.7 billion in 1900, and the population grew even faster in recent history. There was 2.8 billion in 1955, 5 billion in the 1980’s, and 6 billion in late 1999.(1) Human population growth has departed from the standard S-shaped curve where populations grow rapidly until they hit a maximum where they level off and sometimes decrease slightly. Humans were able to alter the curve because they have gained the ability to modify their environment. In other words, the population can grow faster because of technology and the ‘tech fix.’ The doubling time of human populations has been decreasing steadily. Additionally, agricultural and industrial technological advances have enhanced the earth’s carrying capacity and kept the population growth curve from leveling off.(2)


   Population growth rates have decreased slightly, but are still high in developing nations. On the contrary, growth rates have declined even more significantly in developed countries with most countries exhibiting below replacement levels.(3) This has significance in several ways. One notable way is best expressed by discussing the environmental Kuznets curve. Dasgupta, Laplante, Wang, and Wheeler provide a full explanation and critique of the Kuznet curve of pollution and economic development. The basic explanation states:



“In the first stage of industrialization, pollution in the environmental Kuznets curve world grows rapidly because people are more interested in jobs and income than clean air and water, communities are too poor to pay for abatement, and environmental regulation is correspondingly weak. The balance shifts as income rises."(4)




The report claims that the $5000 to $8000 per capita income range is the critical place where air and water pollution flatten and begin to decrease as the income continues to increase. Below this income level, pollution increases along with development. This is interpreted as suggesting a method of, “Grow first, then clean up.”(5)An even more optimistic view of the relationship between pollution and development displays a lower curve, signaling lower levels of pollution and has the curve leveling off at a smaller income. Regardless of which version is used, there are conditions that must be met for the Kuznet curve to be relevant. One of the most significant conditions is that this analysis assumes that the pollution externality largely affects local areas and populations, and does not cross borders. If this is not true, the incentive to clean up is significantly decreased.(6) Policymakers need to examine the information regarding the nature of pollution externalities. I suspect that more often than not, the pollution externalities cross borders which would suggest greater difficulty in getting one region to take responsibility for it. Because of the wide-reaching effects that damage to individual parts of the environment has, it is important to figure out a system for dealing with pollution and penalizing the people or industries that are producing it. Although it is not widely agreed upon and does not apply to all environmental measures, the environmental Kuznets curve is a useful way to observe the relationship between pollution and development,


   Because of the massive population growth in developing countries, both rural and urban settings are being adversely affected. The migration to urban centers has besieged the water treatment systems leading to considerable water pollution. This is not only affecting the environment, but also bringing about serious health issues for people in these cities. Even though many people are leaving the rural areas for cities, the increasing populations mean that rural populations are growing as well. This is resulting in destruction of forests, loss of habitat (and thus biodiversity), and overuse of land leading to erosion of hillsides and silting of rivers.(7) Some direct consequences of this are a decrease in the stability of the ecosystems due to the loss of biodiversity, and an increase of carbon dioxide that is remaining in the atmosphere because of deforestation.(8) The existing poverty in developing countries is worsened by the population growth which makes it necessary to spend the majority of income on basic needs and leaves less to be spent on other investments and services. For the 80% of the world population that is suffering from mild to severe deprivation,(9) it would only make sense that worrying about the environment is not at the top of their list of concerns when it is contending with things like worrying where the next meal coming from. The environmental Kuznets curve captures this idea and examines it from an economic perspective that considers the other factors at play. It provides a good starting point to examine where different regions of the world are in addressing, or having the ability to address, environmental issues.


   To end on a more hopeful note, Wattenberg in his article It Will Be a Smaller World After All claims, “the environmental future looks better.” He states that previous predictions regarding global warming were established according to expectations of a much higher population in the near future. With projections estimating a population peak of slightly less than 9 billion followed by a decrease in world population, pollution should not reach the previously expected concentrations and “clean water and clean air should be more plentiful.”(10) Hopefully more information and concern coupled with less severe population increases can decrease the amount of damage done to the environment.



 Works Cited

Raleigh, V. S. “Trends in world population: how will the millennium compare with the past?” Human Reproduction Update, 5(5). (1999). p. 500-505.

Dolan, Edwin G., Ch. 5 from "TANSTAAFL: The Economic Strategy for Environmental Crisis" 1974, pp. 55-72.

Wattenberg, Ben J. "It Will Be a Smaller World After All." The New York Times 8 Mar. 2003.

Dasgupta, Susmita, Benoit Laplante, Hua Wang, and David Wheeler. "Confronting the Environmental Kuznets Curve." Journal of Economic Perspectives 16.1 (2002): 147-168.

"The Magnitude of Population Growth and Its Consequences." Population Media Center . 12 Apr. 2006 <>.

Wattenberg, Ben J. "It Will Be a Smaller World After All." The New York Times 8 Mar. 2003.


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last updated 1/25/06