Cover Image
close this bookBasic Concepts in Environment, Agriculture and Natural Resources Management: An Information Kit (IIRR, 1993, 151 p.)
close this folderEcological basics
View the documentEcosystem degradation
View the documentHabitat and niche
View the documentThe food chain
View the documentBiological magnification
View the documentNitrogen cycle
View the documentSociety and the carbon-oxygen cycle
View the documentHealth consequences of environmental degradation
View the documentPopulation and the environment

Population and the environment

Population and the environment

Population and the environment

Humankind has been blessed with vast resources upon which it depends. However, unchecked population growth places tremendous demands on mother nature. An increase in population means an increase in the following needs: food, water, energy, clothing, housing, consumer goods, infrastructure all of which can lead to environmental degradation.

Population data

Table 1. Philippine population and annual growth rates. (1970-1990)


Population rate (in millions)

Growth rates (in percent)


36.7 -






















Source: National Census and Statistics Office Survey

Population Impacts

Sheer Numbers

All of toe more than one million Filipinos being added to the country' s population each year have basic needs for food, energy, housing and other necessities. Fulfilling these needs, even at a minimal level, has an impact on the environment. For example, each person needs an average of 2,350 food calories (car) daily to be healthy and productive. These food calories must be produced from existing land and water resources. Where people rely on wood for fuel, each rural resident needs about 7.5 trees annually for fuelwood, or 75 trees per person in a 10-year planting and harvesting cycle.

Multiplying factors

Each individual's impact on the environment is multiplied by his/her level of consumption of natural resources and the level of technology used to support that level of consumption.


Population growth increases the density of urban and rural human settlements beyond the ability of local ecosystems to renew themselves or to absorb wastes. Concentrations of people can overwhelm municipal services such as water supply, sanitation, housing, energy and transportation. This also contributes to many health problems such as tuberculosis, viral infections and other contagious diseases.

Pace of Change

Many developing countries, like the Philippines, can barely keep up with the increasing demand for food, jobs and housing. The pace has forced people to adopt environmentally damaging production methods. Increasing demand for consumer goods and the rising need to strengthen the economy have brought an era of increasing industrialization and urbanization.

Threshold Effects

Threshold effects can either be biological or economic. Biological thresholds stem from the increasing stress that additional humans place on natural ecosystems. For example, a lake may be able to absorb the sewage of 500 people but will suddenly cease to support plants and fish if the polluting population grows to 505 people. Economic threshold effects can cause dramatic increase in costs. As more people require more food, energy, wafer end minerals, these resources become scarce or less accessible; therefore, raising their prices and requiring continuous search for substitutes.

Global-carrying capacity

Global-carrying capacity is defined as the maximum human population that the earth can support indefinitely on a specific resource base, using a specific level of technology. There are physical limits to the carrying capacity of the earth:

· The finite capacity of natural systems to provide food and energy and to absorb wastes

· The amount of greenhouse gases that accumulate in the atmosphere without triggering irreversible climatic changes

· The amount of fresh water available to support humans, other animals and plants

· Grasslands take a year to grow back after overgrazing.

· Fish stocks may take five years to return to previous levels after moderate overfishing.

· Forest ecosystems may take 20 to 100 years to grow back.

· Topsoil takes hundreds of years to form.

· Aquifers can take between one and thousands of years to refill.

· Ultimately, the issue of how humans and the earth can reconcile their compatible needs remains a big challenge.