Human Population Dynamics | Environmental Article

Written By Samantha Gibbons, Age 16 Arizona, USA


“It always seems impossible until it’s done” (Nelson Mandela). Over the last relatively minuscule geological time frame, the human population has exponentially increased at an uncanny rate. In 2050, the human population is expected to be over nine billion people. Since this number is quite perplexing, how did humans even manage to achieve this skyrocketing rate? Approximately 12,000 years ago, agricultural societies began to develop in such a way as to mass-produce food efficiently. Food production and the human population go hand-in-hand. By allowing more food to be produced, the quality of living began to increase. Currently, the growth rate is around 1.08% per year, but it is gradually beginning to decrease. The majority of this growth is occurring in developing countries, like Africa and Asia.


Some of the greatest influences on the overall human population growth are improved medical care and sterilization. These factors have allowed the growth rates to decrease as more people were able to reach their reproductive years (about 15 years of age to 44 years of age) and live a longer, healthier time during those years. Because developing countries do not have as much access to these resources, the majority of the growth (approximately 97%) will be occurring in the years to come.

The human population, to a great extent, correlates to environmental dilemmas; humans are altering nature to meet our personal needs. To further elaborate, humans are reducing biodiversity by logging forests to create products such as paper and furniture. Humans are also instigating invasive species into various communities, and with this comes extra consumption of limited resources. Specifically concerning water, humans are utilizing resources at a much more rapid pace than they can be replenished. With that being said, another abiotic source that is caused by human reliance is carbon dioxide fossil fuel emissions. As both industrialization and urbanization have become increasingly widespread over the past couple of decades, the amount of air pollution has risen about 6% overall. All of these modifications impede the planet’s natural cycling.


With technological advances being discovered at a rapid pace, the life expectancy in both developed and developing countries is predicted to increase as it pertains to a direct relationship. So, how many people can the Earth sustain? Earth’s carry capacity is a highly debated subject because there are so many variables that contribute to the answer. Before diving into the infinite depths to supposedly propose a solution to this significant inquiry, there are two primary types of carrying capacities to be defined. Foremost, there is ecological carrying capacity — the maximum population of a species of a particular habitat that an ecosystem can sustain without being degraded. However, there is also cultural carrying capacity — the maximum number of people who could live in reasonable freedom and comfort indefinitely without decreasing the ability of the earth to sustain future generations. More frequently than not, it is difficult for humans to think long-term rather than short-term. It is important to consider what can be sustainable for the well-being of the planet, but also what is still comfortable for humans living on a daily basis.


With having these terms defined, there is no exact answer as to how many humans the Earth can hold. As the future is unknown regarding innovation and technology, the rules of population to other species do not apply to humans. For instance, a man named Thomas Malthus proposed a theory back in 1798 about food production and population growth. Now called the Malthusian Theory, it states how the human population would continue to grow and outpace food production. He also believed that the human population would experience dieback because he assumed that food production grew exponentially. Because resources were being quickly taken advantage of, he sought out that the carrying capacity would decrease. This meant that the human population would overshoot Earth’s carrying capacity and thus experience dieback. Despite the precise logic he hypothesized and proposed, the Malthusian theory was not supported. He did not take into consideration the development of technology. The Industrial Revolution started in the mid-1700s, and he failed to account for the opening of new lands, especially in the new world. Furthermore, he failed to anticipate the succeeding falling fertility rates due to increased externalities.


In general, there are a multitude of factors that go into birth and fertility rates corresponding to human population dynamics. Typically associated with the lower socioeconomic realm, the importance of children as part of the workforce is a determining factor as they aid families in occupational facilities. Along with this comes the cost of raising and educating children. Depending on where a family is located can determine how urbanized the surrounding area is, which also needs to be considered. Steering towards more of an equality principality, the increase in educational and employment opportunities for women has caused fertility rates to decrease. As women are granted equal access to these situations, the average age of marriage changes, which affects how many children a woman may have as well. Of course, the availability of legal abortions and birth control are direct restrictions to having children. Some countries do not allow these contraceptives due to religious affiliations, traditions, and cultural norms.


Demographers (scientists who study human populations) have collectively found that the most effective way to measure a nation’s quality of life is through infant mortality and life expectancy. Infant mortality rate (IMR) is the number of babies per 1,000 people that die before their first birthday. Between 1965 and 2008, the world’s IMR dropped from 20 to 6.3 in developed countries and 118 to 59 in developing. In the United States, the IMR was 165 in 1900 and had a sharp decrease to 5.8 in 2019. This data can reflect the country’s general nutrition and health care level. Currently, there are forty countries lower than the United States due to inadequate health care for poor women, drug addiction, and teen pregnancy. Life expectancy refers to the average number of years a newborn can expect to live. Just between 1965 and 2008, the global life expectancy increased from 48 to 68. In developed countries, the average is 67, whereas in developed countries it is about 77. In the United States, the life expectancy was 48 in 1900 and is 78 in 2021. As previously touched on, this is because of better nutrition, medical advances, antibiotics, improved sanitation, and especially clean water and vaccines.

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