Population Effects on the Environment

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Editors: K. Lee Lerner , Brenda Wilmoth Lerner , and Sonia Benson
Date: 2013
Publisher: Gale, a Cengage Company
Document Type: Topic overview
Length: 2,481 words
Content Level: (Level 4)
Lexile Measure: 1290L

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Page 88

Population Effects on the Environment


From 1960 to 1999, the population of Earth doubled from three billion to six billion people. On October 31, 2011, the United Nations (U.N.) estimated that the world had reached a population of seven million people. During this period of rapid growth on Earth, the life expectancy and the overall health of most people of the world improved as science, technology, and medicine helped to provide many more benefits for humankind. However, at this same time, this more-than-doubling of the global population took a large toll on the environment as pollution of the air and water increased, depletion of land resources escalated, and degradation to the overall global environment occurred at a rapid pace. This population growth throughout the world has most likely contributed to a large degree to this environmental degradation. In fact, most environmentalists agree that many of Earth's environmental problems such as climate change, species loss, and resource degradation are exacerbated by population growth. American author Robert Engelman, who is the president of the Worldwatch Institute, supports this stance. In 1999, when he was with Population Action International, Engelman stated, “Trends such as the loss of half of the planet's forests, the depletion of most of its major fisheries, and the alteration of its atmosphere and climate are closely related to the fact that human population expanded from mere millions in prehistoric times to over six billion today.”

In the early part of the twenty-first century, the United Nations estimated that Earth's population is growing by about 80 million people per year. By 2050, the U.N. is expecting Earth's population to exceed nine billion people. Although fertility rates have declined in most developed regions of the world, these rates are still high in developing areas such as Africa, Asia, and South America. For instance, in many countries of Africa, a woman of child-bearing age is having, on average, six or

China Water Shortages. Chinese workers pour water into a polluted canal after rinsing their bowls used for lunch in Beijing, China. With about 20 percent of the worlds population but only 7 percent of the worlds China Water Shortages. Chinese workers pour water into a polluted canal after rinsing their bowls used for lunch in Beijing, China. With about 20 percent of the world's population but only 7 percent of the world's water resources, China faces challenges providing adequate quantities of clean water to both rural and urban residents. © AP Images/Ng Han Guan

seven children, as opposed to such developed areas as the United States where around two children are the norm. To make matters worse, these rapidly growing undeveloped countries are much less likely to be able to support such growth due to often limited natural resources and technical abilities.

Historical Development

There is no concrete way, with present technology, to directly relate a rapidly growing population to degraded environmental change. However, it is clear from historic data that as the global population has continued to increase there is growing concern that any expanding population of people causes increasing environmental problems because only limited natural resources, such as arable land, potable water, forests, and fisheries, are available on Earth. For example, a growing population places an increased strain on the availability of non-renewable resources such as fossil fuels, including coal and petroleum products.

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The Effects of Population on the Environment. The human footprint shows the ecological impact of people on Earths ecosystems. The growth of the global population has taken a large toll on the planet. The Effects of Population on the Environment. The “human footprint” shows the ecological impact of people on Earth's ecosystems. The growth of the global population has taken a large toll on the planet. Historic data indicate that as the global population has continued to increase, environmental problems have escalated as well, because only limited natural resources, such as arable land, potable water, forests, and fisheries, are available. Most environmentalists agree that many of Earth's environmental problems such as climate change, species loss, and resource degradation are exacerbated by population growth. Wildlife Conservation Society XNR Productions

As of the beginning of the twenty-first century, about 80 percent of the world's population lived in developing countries of the world such as India and China. As these countries grow, the increased number of people places extreme pressures on these countries to construct the infrastructure (such as buildings, roads, and sanitary systems) needed to support these populations. When population growth outpaces such construction, degradations to the environment, usually in the form of pollution, invariably result.

Over the past 300 years, the amount of cultivated land on Earth has increased by over 450 percent, increasing from 2.7 million square kilometers (1.0 million square miles) to 15.0 million square kilometers (5.8 million square miles). This, in turn, causes deforestation as trees are destroyed to make way for agriculture. In fact, from 1980 to 1995, 72 hectares (180 million acres) of forests were eliminated, mostly in developing regions of the world. Nearly half of Earth's original forests have been lost, and each year another 16 million hectares (40 million acres) are destroyed through burning, bulldozing, or being cut down. As forests are eliminated, there is increased risk for soil erosion; and as agriculture is increased, further degradations to the soil are likely with the use of fertilizers and pesticides. In addition, even though trees are renewable resources for the world, as more forests are turned into agricultural areas, there are fewer areas for the growing of trees.

Due to the rapidly increasing population of the world, the public health of much of the world is being threatened. Unclean water and poor sanitation kills over 12 million people each year, most in developing countries. In addition, air pollution kills nearly 3 million more annually. Heavy metals and other chemical contaminants also cause widespread health problems. The food supply of many countries is also threatened. According to the United Nations' Food and Agriculture Organization, 64 of 105 developing countries have populations that are growing faster than their food supplies, primarily due to the degradation of arable lands through increased food production. Further, it is projected by the U.N. that by 2025, when the population of the world is estimated to be about eight billion, around 48 countries, with a combined population of about three billion people, will have water shortages.

Coastal ecosystems are also being placed under ecological pressures from high population densities and Page 90  |  Top of Articleincreasing urban development. In addition, the world's seas are being increasingly polluted from human activities, while ocean fisheries are being overexploited in an attempt to feed the world's growing population. In all, about two-thirds of the world's species are in decline. Such decline causes increased problems for humans because a rich biological diversity (what is called biodiversity) is crucial to agriculture, medicine, and many other important areas to human health. Without a doubt, the dramatic population growth of humans is rapidly increasing the extinction rate of many plants and animals on Earth.

The reason for targeting the poorest countries is explained by the United Nations with the following statement: “The largest population increases and the most fragile environmental conditions are usually found in poor countries, which typically have limited financial means and least adequate political and managerial resources to address the challenges.”

Global climate change has been apparent due to the warming of waters and atmosphere of Earth. Research seems to indicate that some of this global warming is due to human activities (while other is due to natural cycles). The real question is just how much of global climate change is due to human activities. Scientists are still trying to decide this question. Scientists do know that increased industrial production and energy consumption since the Industrial Revolution, which began in England in the late eighteenth century, has introduced carbon dioxide emissions from the burning of fossil fuels into the atmosphere. In addition, the reduction in forested areas, along with the increase in agricultural areas, has led to increases in human-induced greenhouse gases such as carbon dioxide and methane. As the temperature of Earth's atmosphere increases from global warming, the sea levels rise due to melting of glaciers in the North and South Poles. Such rising sea levels cause flooding along coastal regions, which leads to further erosion and destruction of the ecosystem.

Current Application

The population of the world is growing at a dramatic rate. Increases in population size, rate of growth, and its distribution throughout the world have major impacts on the environment. However, data show that most of this population growth is occurring in the poor countries of the world. The United Nations' report Linking Population, Poverty and Development: Environmental Sustainability: Population, Poverty and the Environment states, “Environmental sustainability is essential to achieving the Millennium Development Goals, especially poverty reduction.” These MDGs are being implemented primarily toward the poorest countries of the world. The reason for targeting the poorest countries is explained by the United Nations with the following statement: “The largest population increases and the most fragile environmental conditions are usually found in poor countries, which typically have limited financial means and least adequate political and managerial resources to address the challenges.” This threatens sustainable development and produces further deterioration in living standards and quality of life. Environmental crises, including those brought on by changing weather patterns, have the greatest impact on the poor in developing countries.”

Further, Earth has a limited carrying capacity, which means that Earth can substantially support only so many people. Exceeding this capacity of Earth would result in global environmental hazards, along with many other problems. To prevent this from happening, the United Nations has instituted its Millennium Development Goals to encourage development in the world's poorest countries by improving their social and economic conditions. As these conditions are improved, the rate at which the world's population is growing will decrease, which, in turn, will help to alleviate some of the world's environmental problems.

These Millennium Development Goals include eight international development goals that, it is hoped, will be achieved by the year 2015. The eight goals, along with each of their targets, are:

  1. Goal: Eradicate extreme poverty and hunger.
    • Target: Halve, between 1990 and 2015, the proportion of people whose income is less than $1 a day.
    • Target: Achieve full and productive employment and decent work for all, including women and young people.
    • Target: Halve the proportion of people who suffer from hunger.
  2. Goal: Achieve universal primary education.
    • Target: Ensure that, by 2015, children everywhere, boys and girls alike, will be able to complete a full course of primary schooling
  3. Goal: Promote gender equality and empowering women.
    • Target: Eliminate gender disparity in primary and secondary education, preferably by 2005, and in all levels of education no later than 2015. Page 91  |  Top of Article
  4. Goal: Reduce child mortality rates.
    • Target: Reduce by two thirds, between 1990 and 2015, the under-five mortality rate.
  5. Goal: Improve maternal health.
    • Target: Reduce by three quarters the maternal mortality ratio
    • Target: Achieve universal access to reproductive health.
  6. Goal: Combat HIV/AIDS, malaria, and other diseases.
    • Target: Have halted by 2015 and begun to reverse the spread of HIV/AIDS.
    • Target: Achieve, by 2010, universal access to treatment for HIV/AIDS for all those who need it.
    • Target: Have halted by 2015 and begun to reverse the incidence of malaria and other major diseases.
  7. Goal: Ensure environmental sustainability.
    • Target: Integrate the principles of sustainable development into country policies and programs and reverse loss of environmental resources.
    • Target: Reduce biodiversity loss, achieving, by 2010, a significant reduction in the rate of loss.
    • Target: Halve, by 2015, the proportion of the population without sustainable access to safe drinking water and basic sanitation.
    • Target: By 2020, to have achieved a significant improvement in the lives of at least 100 million slum-dwellers.
  8. Goal: Develop a global partnership for development.
    • Target: Develop further an open, rule-based, predictable, non-discriminatory trading and financial system.
    • Target: Address the Special Needs of the Least Developed Countries (LDC).
    • Target: Address the special needs of landlocked developing countries and small island developing States.
    • Target: Deal comprehensively with the debt problems of developing countries through national and international measures in order to make debt sustainable in the long term.
    • Target: In cooperation with pharmaceutical companies, provide access to affordable essential drugs in developing countries.
    • Target: In cooperation with the private sector, make available the benefits of new technologies, especially information and communications.

Ensuring environment sustainability is one of the eight MDGs. Within environment sustainability, four areas are extremely important for improving the population-environment issues for the world: access to safe drinking water, access to basic sanitation services, biodiversity conservation, and slums. The United Nations has declared that about 1.7 billion people have gained access to safe drinking water since 1990; however, 884 million people worldwide still do not have such access.

In addition, about 2.6 billion people still lack access to basic sanitation services, such as latrines or toilets. Concerning sanitation, the U.N. states, “With half the population of developing regions lacking basic sanitation, the 2015 target appears to be out of reach. At the current rate of progress, the world will miss the target of halving the proportion of people without access to basic sanitation, such as toilets or latrines. In 2008, an estimated 2.6 billion people around the world lacked access to improved sanitation. If the trend continues, that number will grow to 2.7 billion by 2015.”

The U.N. also states that the 2010 target for biodiversity conservation was missed. Based on current data, the loss of species will continue throughout the twenty-first century. The U.N. states, “Nearly 17,000 species of plants and animals are currently at risk of extinction, and the number of species threatened by extinction is growing by the day. Despite increased investment, the main causes of biodiversity loss—high rates of consumption, habitat loss, invasive species, pollution and climate change—are not being sufficiently addressed. Biodiversity is vitally important; billions of people rely directly on diverse species for their livelihoods and often survival.”

Although the percentage of the urban population that still lives in slums is declining, the absolute number of slum dwellers is still increasing. As of the beginning of the 2010s, about 828 million people live in slums around the world. Concerning slum dwellers, the U.N. states, “The target of improving the lives of at least 100 million slum dwellers has already been achieved twice-over. In the last ten years, more than 200 million slum dwellers have gained access to improved water, sanitation or durable and less crowded housing, greatly enhancing their prospects of escaping poverty, disease and illiteracy.”

Population dynamics, which includes growth rates, age structure, fertility and mortality, migration and other factors, influence every aspect of human, social, and economic development. When these Millennium Development Goals are accomplished, a major decrease in the rate of the world's population growth is expected to occur. Consequently, a parallel improvement in the world's environment is predicted to result, too. The International Conference on Population and Development, a part of the United Nations, concluded, based on these eight MDGs: “Explicitly integrating population into economic and development strategies will both Page 92  |  Top of Articlespeed up the pace of sustainable development and poverty alleviation and contribute to the achievement of population objectives and an improved quality of life of the population.”

The October 25, 2007 New York Times article “UN Issues ‘Final Wake-up Call’ on Population and Environment” provides an excellent summary on the state of the world looking out into the future with respect to population growth and environment degradation. It states, “The human population is living far beyond its means and inflicting damage on the environment that could pass points of no return, according to a major report issued Thursday by the United Nations. Climate change, the rate of extinction of species and the challenge of feeding a growing population are among the threats putting humanity at risk, the UN Environment Program said in its fourth Global Environmental Outlook since 1997.” Achim Steiner, the executive director of the U.N. program, stated, “The human population is now so large that the amount of resources needed to sustain it exceeds what is available at current consumption patterns.” Steiner states that the efficient use of resources and reducing waste now are “among the greatest challenges at the beginning of 21st century.”



Beaton, Charles, R., and Chris Maser. Economics and Ecology: United for a Sustainable World. Boca Raton, FL: CRC Press, 2012.

Hunter, Lori, M. Environmental Implications of Population Dynamics. Santa Monica, CA: RAND Corporation, 2001.

Langwith, Jacqueline. Population, Resources, and Conflict. Detroit: Greenhaven Press, 2011.

Sinha, B.R.K., ed. Population, Environment and Development: A Global Challenge for the 21st Century. New Delhi, India: New Century Publications, 2009.

Web Sites

“Goal 7: Ensure Environmental Sustainability.” United Nations. http://www.un.org/millenniumgoals/environ.shtml (accessed July 28, 2012).

“Linking Population, Poverty and Development.” Population Fund, United Nations. (December 15, 2005). http://www.unfpa.org/pds/sustainability.htm (accessed July 28, 2012).

“Population.” United Nations. http://www.un.org/en/development/progareas/population.shtml (accessed July 28, 2012).

“Sustainable Development, Human Settlements, and Energy.” United Nations. http://www.un.org/en/development/progareas/dsd.shtml (accessed July 28, 2012).

“UN Issues ‘Final Wake-Up Call’ on Population and Environment.” The New York Times. October 25, 2007. http://www.nytimes.com/2007/10/25/world/europe/25iht-environ.4.8056185.html?pagewanted=all (accessed July 28, 2012).

“We Can End Poverty 2015: Millennium Development Goals.” United Nations. http://www.un.org/millenniumgoals/poverty.shtml (accessed July 28, 2012).

William Arthur Atkins

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Gale Document Number: GALE|CX2062300039