What Is An Ecological Footprint?

Intimately tied into discussions of sustainability is the phrase "ecological footprint," a measure of humankind's impact on the environment. Footprints can be assessed on individual and community levels or at much broader scales--all the way up to a snapshot of the entire world population.

Definition

An ecological footprint measures the impact on environmental resources by human beings on an individual or collective scale. It can be thought of as the amount of land and water a human requires for consumption and the absorption of wastes. For example, researchers can estimate the ecological footprint of an individual living in Perth, Australia; the footprint of the city itself; the footprint of Australia as a whole; or the entire global ecological footprint. The concept sprang from the work of two University of British Columbia researchers, Mathis Wackernagel and William Rees, in the early 1990s.

Components

The footprint consists of such resource needs as food, water and building materials, as well as energy use, including the release of carbon dioxide from fossil-fuel consumption. For the individual, the impact of such needs and activities goes well beyond the specific home geography: Fish eaten may be captured thousands of miles away, produce may be grown and wood products harvested in another hemisphere, and pollution may impact a broad area.

Overshoot

In the late decades of the 20th century, the World Wildlife Fund reports, the global human population began overtaxing the planet's ecological budget: Resources are now exploited at a greater rate than they are replenished, and waste production exceeds waste absorption. The Global Footprint Network, which measures and tracks changes in worldwide resource use and waste generation, reports that, as of 2009, "it now takes the Earth one year and five months to regenerate what we use in a year."

Comparisons

Because of differing patterns of resource use and waste production, countries have varying ecological footprints. The 2008 Living Planet Report, released by the Global Footprint Network, the World Wildlife Fund and the Zoological Society of London, showed that, in 2005, the United States and China both used 21 percent of Earth's biocapacity; China, with its much larger population, had a smaller per capita effect. Using 7 percent of the planetary biocapacity, with the third largest footprint was India.

Calculating and Reducing

Many websites now offer ecological footprint calculators for individuals to estimate their own impact--as well as tips on how to reduce it. At a basic level, cataloging your daily use of resources--from eating habits to transportation routines--can quickly generate a rough idea of your footprint.
Reducing energy and water consumption, for example, can help decrease your footprint, as can paying close attention to the origin and costs of your daily food. These same efforts, applied on a broader scale, can tackle humankind's global ecological footprint.