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12.1: History of Human Population Growth

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    The human population is growing rapidly. For most of human history, there were fewer than 1 billion people on the planet. During the time of the Agricultural Revolution, 10,000 B.C., there were only 5-10 million people on Earth - which is basically the population of New York City today. In 1800, when the Industrial Revolution began, there were approximately 1 billion people on Earth. Continued agricultural expansion and extraction of fossil fuels and minerals led to rapid global economic growth and, in turn, population growth in the 19th century. We’ve added over 6 billion people to the human population in just a little over 200 years (figure \(\PageIndex{a}\)). As of August 2020, the global human population is around 7.8 billion people. 

    Although global population size continues to increase, the rate of human population growth has decreased. This means that the population size is not increasing as quickly as it did in the past (figure \(\PageIndex{a}\)).

    Graph of world population size and population growth rate over time

    Figure \(\PageIndex{a}\): Human population growth. Since 1700, human population size (shaded in teal) has increased. It reached 1 billion in 1803, 2 billion in 1928, 2.5 billion in 1950, 5 billion in 1987, and 7.7 billion in 2019. It is projected to reach 10.9 billion in 2100. The population growth rate (pink line) was only 0.04% on average between 10,000 BCE and 1700. The population growth rate peaked in 1968  at 2.1%, and since then, it has slowed to 1.08% in 2019 and is projected to be at 0.1% in 2100. Image by Max Roser (2013) "Future Population Growth". Published online at (CC-BY)

    The fundamental cause of the acceleration of growth rate for humans in the past 200 years has been the reduced death rate due to changes in public health and sanitation. Clean drinking water and proper disposal sewage has drastically improved health in developed nations. Also, medical innovations such as the use of antibiotics and vaccines have decreased the ability of infectious disease to limit human population growth. In the past, diseases such as the bubonic plaque of the fourteenth century killed between 30 and 60 percent of Europe’s population and reduced the overall world population by as many as one hundred million people. Naturally, infectious disease continues to have an impact on human population growth, especially in poorer nations. For example, life expectancy in sub-Saharan Africa, which was increasing from 1950 to 1990, began to decline after 1985 largely as a result of HIV/AIDS mortality. According to a 2016 study by Marcus et al., The reduction in life expectancy caused by HIV/AIDS was estimated to be 8 years for 2016.

    Human technology and particularly our harnessing of the energy contained in fossil fuels have caused unprecedented changes to Earth’s environment, altering ecosystems to the point where some may be in danger of collapse. Changes on a global scale including depletion of the ozone layer, desertification and topsoil loss, and global climate change are caused by human activities.


    Marcus, J. L., Chao, C. R., Leyden, W. A., Xu, L., Quesenberry, C. P., Jr, Klein, D. B., Towner, W. J., Horberg, M. A., & Silverberg, M. J. (2016). Narrowing the Gap in Life Expectancy Between HIV-Infected and HIV-Uninfected Individuals With Access to CareJournal of acquired immune deficiency syndromes (1999)73(1), 39–46.


    Modified by Melissa Ha from the following sources: