Population growth is the increase in the number of humans on Earth. For most of human history our population size was relatively stable. But with innovation and industrialization, energy, food, water, and medical care became more available and reliable. Consequently, global human population rapidly increased, and continues to do so, with dramatic impacts on global climate and ecosystems. We will need technological and social innovation to help us support the world’s population as we adapt to and mitigate climate and environmental changes.
Human population growth impacts the Earth system in a variety of ways, including:
- Increasing the extraction of resources from the environment. These resources include fossil fuels (oil, gas, and coal), minerals, trees, water, and wildlife, especially in the oceans. The process of removing resources, in turn, often releases pollutants and waste that reduce air and water quality, and harm the health of humans and other species.
- Increasing the burning of fossil fuels for energy to generate electricity, and to power transportation (for example, cars and planes) and industrial processes.
- Increase in freshwater use for drinking, agriculture, recreation, and industrial processes. Freshwater is extracted from lakes, rivers, the ground, and man-made reservoirs.
- Increasing ecological impacts on environments. Forests and other habitats are disturbed or destroyed to construct urban areas including the construction of homes, businesses, and roads to accommodate growing populations. Additionally, as populations increase, more land is used for agricultural activities to grow crops and support livestock. This, in turn, can decrease species populations, geographic ranges, biodiversity, and alter interactions among organisms.
- Increasing fishing and hunting, which reduces species populations of the exploited species. Fishing and hunting can also indirectly increase numbers of species that are not fished or hunted if more resources become available for the species that remain in the ecosystem.
- Increasing the transport of invasive species, either intentionally or by accident, as people travel and import and export supplies. Urbanization also creates disturbed environments where invasive species often thrive and outcompete native species. For example, many invasive plant species thrive along strips of land next to roads and highways.
- The transmission of diseases. Humans living in densely populated areas can rapidly spread diseases within and among populations. Additionally, because transportation has become easier and more frequent, diseases can spread quickly to new regions.
Can you think of additional cause and effect relationships between human population growth and other parts of the Earth system?
Visit the burning of fossil fuels, agricultural activities, and urbanization pages to learn more about how processes and phenomena related to the size and distribution of human populations affect global climate and ecosystems.
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Learn more in these real-world examples, and challenge yourself toconstruct a modelthat explains the Earth system relationships.
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FAQs
There's a popular misconception that the global population is growing exponentially. But it's not. While the global population is still increasing in absolute numbers, population growth peaked decades ago. In the chart, we see the global population growth rate per year.
What is your understanding about population growth? ›
Population growth is the increase in the number of people in an area. Census is the official count of people in a country. The three factors affecting population growth are: the fertility rate, life expectancy, and net immigration rate.
What is the population change short answer? ›
Population change, defined generally, is the difference in the size of a population between the end and the beginning of a given time period (usually one year). Specifically, it is the difference in population size on 1 January of two consecutive years.
How is population growth a global issue? ›
We have to address overpopulation
More people require more food, water, sanitation, homes, public services, and amenities – but our Earth is struggling to cope. Populations of wild species have plummeted, global temperatures are rising, our seas are full of plastic and forests are disappearing.
Is our population growth slowing? ›
Population growth has declined mainly due to the abrupt decline in the global total fertility rate, from 5.3 in 1963 to 2.3 in 2021. The decline in the total fertility rate has occurred in every region of the world and is a result of a process known as demographic transition.
How fast is the global population currently growing? ›
Population growth is the increase in the number of people in a population or dispersed group. Actual global human population growth amounts to around 83 million annually, or 1.1% per year. The global population has grown from 1 billion in 1800 to 8 billion in 2024.
What is population growth and change? ›
Population growth refers to the change in the number of inhabitants of a country and territory during a specific period of time like the last ten years, last 15 years and so on. Population change refers to the change in the number of people during a specific period of time.
What causes population change and growth? ›
There are three components of change: births, deaths, and migration. The change in the population from births and deaths is often combined and referred to as natural increase or natural change.
How many humans will there be in 3000? ›
The U.N. estimates that the world population as a whole will peak around 2100 at 11 billion as the last developing countries develop. Then it will start going down. So if current trends continue around the world there would likely be 0 people left by the year 3000.
What is the main cause of overpopulation? ›
Due to immigration, the decline in mortality rates, medical breakthroughs, and increased birth rates, populations will always increase and eventually gives rise to overpopulation.
The projected world population on Jan. 1, 2024, is 8,019,876,189, an increase of 75,162,541 (0.95%) from New Year's Day 2023. During January 2024, 4.3 births and 2.0 deaths are expected worldwide every second.
Do populations grow exponentially? ›
In exponential growth, a population's per capita (per individual) growth rate stays the same regardless of population size, making the population grow faster and faster as it gets larger. In nature, populations may grow exponentially for some period, but they will ultimately be limited by resource availability.
Is the human population growing exponentially True or false? ›
The statement False is correct. The human population is not currently experiencing exponential growth. Exponential growth occurs when the population size increases at an accelerating rate over time.
Is the world's population growing and aging? ›
Every country in the world is experiencing growth in both the size and the proportion of older persons in the population. By 2030, 1 in 6 people in the world will be aged 60 years or over. At this time the share of the population aged 60 years and over will increase from 1 billion in 2020 to 1.4 billion.
