Human overpopulation

Looking at human overpopulation and its effects on the environment, how this happens, and what can be done to help.

Interesting population facts -

Human overpopulation showing a crowded sidewalk

Over 7 billion people inhabit the planet now compared to 3 billion back in 1967!

Our global population is growing by 83 million people annually.

The population is expected to reach 8.6 billion in 2030, 9.8 billion in 2050, and 11.2 billion in 2100.

50.4% of the world's population is male and 49.6% is female.

The median age of the global population is 30 years.

Globally, life expectancy at birth is projected to rise from 71 years in 2010-2015 to 77 years in 2045-2050

What does overpopulation mean?

Human Overpopulation occurs when the number of people in a particular region exceeds the carrying capacity of that area. This results in the depletion of natural resources and environmental deterioration among other problems.

Carrying capacity is the maximum amount of people that can live sustainably within a region for an indefinite about of time, without exhausting natural resources. 

The term human overpopulation often refers to the entire population on Earth and how we're effecting the planet as a whole.

How many people can the Earth support? Scientists estimate the Earth has a maximum carrying capacity of 9-10 billion people. A lack of fresh water and food limitation comes into this equation.

Factors affecting the carrying capacity include -

  • Space vs number of people
  • Birth and death rates
  • Climate
  • Habitat, terrain
  • Food and water supply
  • Availability of other natural resources
  • Amounts of consumption
  • How much waste is produced
  • Waste management
  • Sanitation
  • Environmental policies and laws
  • Conservation efforts
  • Overall impact on the environment 

As of 2018 there were 34 mega cities, defined as having a population in excess of 10 million people.

The top twelve of these cities have 20 million + inhabitants. Tokyo-Yokohama, Jakarta, Delhi, Manila, Seoul-Incheon, Shanghai, Mumbai, New York, Beijing, Sau Paulo, Mexico City, and Guangzhou-Foshan.

A small population living in a big area could still exceed the carrying capacity depending on circumstances. For example people living in a sparse dry area may run short of water and food.

How does human overpopulation occur?

Cityscape representing overpopulation

You'd think with our history of plagues, wars, and natural disasters that there would be way less of us, but the human race is growing fast! Overpopulation happens when there are more births than deaths.   

Increasing number of births 

Developing nations often have poor educational facilities and high illiteracy rates. Marriage is encouraged (especially for girls) at a very young age. In fact some are still practically children when they are paired off. Getting married young increases the chances of having more kids. Most of these people don't have a proper understanding about family planning or the ongoing effects of human overpopulation. They haven't had the opportunities to learn about these topics. Birth control isn't always available, or religious beliefs may oppose their use.

Advancement of fertility treatments in developed countries is enabling couples to have children that they otherwise wouldn't have been able to have naturally. Statistically speaking the issue of high birth rates is still primarily a problem for developing, non western nations.

Reduced mortality rates 

Technological advances in medical treatments, pharmaceutical drugs and better medical facilities are saving lives and enabling people to live longer. In the past certain diseases swept through populations killing thousands or even millions of people. Vaccines are now available which have pretty much eradicated a lot of these infectious diseases.

Agriculture and food distribution

Agricultural productivity is believed to be a contributing factor towards the population explosion in the last 50 years. Technology in the way of farming equipment (tractors, harvesters etc.) fertilizers, pesticides, and genetic engineering all have played a role. 


People tend to immigrate to developed countries where they have better opportunities and security. Reasons include political freedom, higher standard of living, superior health care, financial security, or education. Although this doesn't add directly to world population, it can create overcrowding problems for the country involved.

Human overpopulation effects on
the environment include  -

  • Water, air, and soil contamination e.g. agriculture, factories, vehicle exhausts
  • Lack of fresh water and food shortages
  • Litter thrown around and trash illegally dumped
  • Plastic and other trash floating around in the oceans
  • Overflowing landfills and excess waste
  • Hazardous waste which puts the public and wildlife in danger
  • Carbon dioxide emissions and other man made greenhouse gases which contributes towards global warming
  • Land degradation e.g. loss of soil nutrients, overgrazing, erosion, quarrying
  • Over exploitation and resource depletion e.g. deforestation, fossil fuels, mining, over fishing
  • Natural habitat destruction, habitat fragmentation, and loss of eco systems

  • Wildlife species becoming critically endangered or extinct because of human activities

  • Industrial disasters such as oil spills or nuclear accidents

  • Civil and political conflict can disrupt and damage the environment

The top ten countries with the highest ecological footprint  (global hectares)

Everyone has an ecological footprint. Countries are measured in global hectares per person. This accounts for the land and resources that we use in our lives. Examples include croplands, grazing land for dairy and meat, fishing in the oceans, forests for lumber, land development, and roading.

The numbers below represent the countries (per capita) ecological footprint.

  1. United Arab Emirates - 10.68
  2. Qatar - 10.51
  3. Bahrain - 10.04
  4. Denmark - 8.26
  5. Belgium - 8.00
  6. United States - 8.00
  7. Estonia - 7.88
  8. Canada - 7.01
  9. Australia - 6.84
  10. Iceland - 6.50

Solutions to overcome human
overpopulation problems

Blackboard wriitng indicating problems and solutions to overpopulation

This is an extremely controversial subject and everyone has their different opinions. Based on our research these are the most recommended ways to help reduce human overpopulation and it's effects on the environment. Solutions begin at the most basic levels.

Awareness of population issues through education

Obviously this is the first step. Teaching about the costs and required resources of bringing up a child should be mandatory for all. It doesn't matter what part of the world you are from. Interestingly, even though developing countries make up the majority of the worlds population, it's the developed countries that use up more natural resources. Overpopulation is linked with poverty and all it's associated problems because of the higher cost of living. Among them are unemployment, inadequate medical care, housing shortages, and social unrest.

Poorer countries have higher incidences of malnutrition (not enough food to go around), disease, and infant mortality rates. One reason why couples from these countries traditionally always had more children is to ensure that some would survive into adulthood.

The children of today grow into adults and then have to face the ongoing difficulties that overpopulation brings. 

Family planning 

Family planning comes hand in hand with education. Of course everyone has the right to have children, although more emphasis should be put on birth control options so that couples can make informed choices for the future. Unplanned pregnancies are common worldwide so this is one area that needs to be addressed.

A report by the U.S. Department of Health and Human Services said that about 37% of births in the United States were unintended at the time of conception (from 2006-2010). The overall proportion of unintended births has not declined significantly since 1982. Studies showed that unintended births put both the mother and child at elevated risk of adverse social economic and health outcomes.

If fewer children are born then population numbers can balance out. Conserving and replenishing resources will become an achievable goal, along with better living standards.

Government initiatives

Governments need to work together with the correct experts and authorities on this subject, to help fund and supply information about human overpopulation to the public. After all, this would be saving the country money and resources in the long run.

Sex education classes help to curb teenage pregnancies. Although these are already part of school curriculum's in many parts of the world, there are still places that miss out on this type of education. 

Cheaper and easier access to contraception (for women and men) is another way that governments can be productive. Millions of people around the world would like the chance to use birth control, but find it difficult or impossible to get, can't afford it, or don't know how to use it properly.

Tax incentives for families with less children has been suggested, but rarely implemented, the effects of this scheme would have to go hand in hand with disincentives for larger families to receive government benefits. A tactic that legislators/politicians find hard to envision, for many reasons, namely, it not being in their economic or political interests. 

Government initiatives must avoid any human rights violations e.g. putting a number on how many children a couple are allowed to have, or forced abortions.


There are endless babies and children who need adoption for whatever reasons. Perhaps adopting a child could become an option for more couples. Foster care is also available in many countries. These are very specialized areas so parents and child must be suitable matches.

 Video about human population throughout the ages

Full list of references for this page

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