Learn more about Population and Carrying Capacity

What are population and carrying capacity, anyway?

Population is a group of people living within an area; for example, the people living in a town, a state, a country, or the world. Urbanization, climate change, birth rate, and migration are all factors in population growth and density.

Learn more about population and replacement rates by watching Population Pyramid, below.

Carrying capacity is the number of individuals that the Earth can support given its available resources without damaging the environment for future generations.

One way to think about the Earth’s carrying capacity is to look at humanity’s ecological footprint. On average, our global population has an ecological footprint of 1.4 planets. We’re already using more than we should in order to allow future generations to live on the planet. However, our ecological footprint varies based on our resource use and consumption habits. If everyone lived like Americans currently do, the world’s estimated ecological footprint would be 5 planets!¹

A crowded steet in Bombay.

Who is most affected? Where are consequences felt?

View the World Population Clock, which gives an up-to-date population estimate.

One estimate is that by 2050, there will be 9.1 billion people on the planet.²

People in the world live in different areas, some of them more densely populated than others. There are 39 mega-cities³, meaning they have over 5 million people. Cities of this size face many challenges: unsafe housing, lack of sufficient drinking water, and the rapid spread of disease. The growing transportation needs, energy use and consumption habits of these densely populated urban areas increase their ecological footprint and cause further environmental problems. In the least developed countries, coastal cities struggle with flooding and coastal erosion, while inland cities are subject to desertification and sandstorms.⁴ 

View this interactive map of population density and major cities all over the globe to get a sense of where density is the highest.

Those who live in rural areas face many challenges as well. Over time, the majority of the rural poor have increasingly become clustered on low-potential land, because of the privatization of land and the increasing commercialization of farming.⁵ Some have continued to farm, while others have migrated to cities to seek a better livelihood. This further increases the density of cities.

A poster describing the experience of a woman who migrated from the Dominican Republic to Italy.

Why are population and carrying capacity important?

Over time, increasing population pressures cause our global ecological footprint to grow. At the same time, the negative effects of using resources beyond our global carrying capacity, such as environmental degradation, natural disasters and conflict, make it more difficult for the planet to support its human population.

It is important to make changes to move toward a sustainable ecological footprint for the health of our planet and that of future generations.

Check out this series of maps that show how population change and climate change impact each other, in terms of temperature, ecological hotspots, precipitation, and agriculture.

How can we address population and carrying capacity challenges?

• By changing our eating, shopping, energy usage, and transportation habits, we can positively impact our ecological footprint.
  
  
• Educating men and women about population growth, so that they think carefully about how many children they want to have.
  
  
• Join a group of youth interested in global issues and creating change.
  
  
• Play the Darfur is Dying game to become more informed about how conflict influences migration. By working for peace around the world, fewer people will be forced to migrate, which will improve living conditions for their families.

Citations

¹ http://www.footprintnetwork.org/en/index.php/GFN/blog/

² http://www.unfpa.org/pds/trends.htm

³ http://www.megacities.uni-koeln.de/documentation/

⁴ http://www.iied.org/pubs/pdfs/G02597.pdf

⁵ http://www.unfpa.org/pds/sustainability.htm