overpopulation effect the environment

How Does Overpopulation Effect the Environment?

Read Time: 4 minutes

Right now, there are upwards of 7.5 billion people living on the planet Earth. They’re of all different creeds and colors, races and religions, but they all have one thing in common — the planet they call home. Unfortunately, we’re getting close to the planet’s maximum sustainable population, which experts estimate at 9 to 10 billion individuals. What are the effects of overpopulation on the environment?


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What Causes Overpopulation?

Overpopulation doesn’t just happen in humans, but we tend to take steps to prevent the natural events that cause large population deaths. The most common causes for overpopulation usually include:

  • An increased birth rate and lower birth mortality rates.
  • Decreased overall mortality rates and increased life spans.
  • Introduction of foreign species — does not generally apply to humans

For humans, in the last 100 years, we’ve improved medical science dramatically, which has helped to increase birth rate, lower overall mortality rate and improve life expectancy. However, how has this affected the planet thus far, and how will it continue to affect it into the future?

5 Effects of Overpopulation

1. No Clean Water

We may live on a water planet, but 97.5% of that water is ocean and other undrinkable salt-filled sources. Only 2.5% of the water on this planet is fresh, and of that, 1% is either too polluted to be consumed or entirely unreachable. Much of it remains frozen in the form of polar ice caps. All told, less than 1% of the planet’s freshwater resources are available for consumption.

Research has shown that, as a species, we’re consuming fresh water faster than the planet can replenish it.

2. Lower Life Expectancy

Thanks to medical intervention, human beings can live to be up to 100 years old — as long as they live in developed countries where they have access to that medical care. One study, done by researchers at Harvard, found that the majority of population increases over the next 40 years or so will be in less developed countries.

Dramatic population increases in these less developed areas will lead to a higher mortality rate and a lower life expectancy because of problems with infrastructure, food, water and housing.

3. Plant and Animal Extinction

Greater numbers of human beings populating the planet means that there are fewer resources available — food, water and habitat, specifically — for other species to thrive. Global warming is already threatening to cause mass flora and fauna extinctions between now and 2050. Scientists are predicting that in that time, more than half of the plant and animal species on the planet could be driven to extinction.

Much of this is due to habitat loss, climate change and the pollution generated by billions of human beings. Many species are also at risk because of overfishing, poaching and our tendency to exploit our natural resources.

The extinction of some species doesn’t just impact us — it impacts the ecosystems where these plants and animals live. Without a careful balance of life forms in an ecosystem, from the smallest single-celled life form to the largest apex predator, ecosystems can collapse, causing the extinction of even surviving species.

4. Soil Depletion From Excessive Farming

Soil nutrition is a delicate balance — planting large numbers of crops can deplete the soil’s natural resources, making it difficult or even impossible to continue to farm in that area. As human populations continue to grow, we will require increasing amounts of food, which requires more and more farmlands that could potentially be depleted.

This also leads to deforestation — much of the drastic deforestation of the rainforest has been completed to create new farmlands for growing populations in the area.

Additionally, this form of intensive farming creates pollution in the form of runoff that carries pesticides and other waste into natural water sources.

5.Climate Change

We’ve been seeing the results of climate change firsthand in the dramatic weather patterns of 2017 — multiple category five hurricanes, dramatic wildfires and floods, and other atypical weather patterns that are threatening both lives and property.

The majority of this is due to human-generated greenhouse gasses that are causing the planet to warm much faster than it would otherwise. The larger the human population is, the more greenhouse gasses we will be creating, making it even more difficult or even impossible to reverse.


Right now, if we destroy our planet, we will have nowhere else to go. If the human population continues to grow unchecked, the effects of overpopulation on the environment will leave us with a planet no longer be able to sustain us.

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Category: Environment


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Article by: Megan Ray Nichols

Megan Ray Nichols is a freelance science writer and science enthusiast. Her favorite subjects include astronomy and the environment. Megan is also a regular contributor to The Naked Scientists, Thomas Insights, and Real Clear Science. When she isn't writing, Megan loves watching movies, hiking, and stargazing.